• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a multi-level modular converter (2) equipped with a control module (4) and a calculator (10) of an internal energy set of the converter stored in the capabilities of the sub-modules of the half-arm. The control module is configured to derive from this internal energy setpoint of the converter a voltage setpoint at the terminals of each modeled capacitor used to regulate the voltage at the connection points of the converter to the DC power supply network and the voltage at the terminals. of each modeled capacitor.
    公开号:FR3039940A1
    申请号:FR1557501
    申请日:2015-08-03
    公开日:2017-02-10
    发明作者:Kosei Shinoda；Abdelkrim Benchaib；Xavier Guillaud；Jing Dai
    申请人:Institut National des Sciences Appliquees de Lyon ；SuperGrid Institute SAS；CentraleSupelec；
    IPC主号:
    专利说明:

    Background of the invention
    The present invention relates to the technical field of modular multi-level converters (MMC) ensuring the conversion of an alternating current into a direct current and vice versa.
    More specifically, it relates to high-voltage direct current (HVDC) transmission networks using direct current for the transmission of electrical energy and in which stations integrate multi-level modular converters.
    In Figure 1, there is shown schematically a set of submodules 6 of a multi-level modular converter 2 according to the prior art. This converter 2 comprises, for a three-phase input / output current (comprising three phases cpa, cpb, and cpc), three conversion arms which are referenced by the indices a, b and c on the various components of FIG. Each conversion arm comprises an upper half-arm and a lower half-arm (indicated by the indices "u" upper and "I" for lower), each of which connects a terminal DC + or DC- of the DC power supply network ( DC) to a terminal of the AC power supply. In particular, each of the arms is connected to one of the three phase lines cpa, cpb, or cpc of the AC power supply network. It should be noted that the terms "arms" and "half-arms" are translated into English respectively by "leg" and "arm". Fig. 1 shows a sub-module assembly 6, wherein each half-arm comprises a plurality of sub-modules SMxij which can be controlled in a desired sequence (with x indicating whether the half-arm is upper or lower, i indicating the arm, and j the sub-module number in the submodules in series in the arm). Here, only three sub-modules have been represented by half-arms. In practice, each lower or upper half-arm may have a number N of a few tens to a few hundred submodules. Each sub-module SMxij comprises a system for storing energy such as at least one capacitor and a control element for selectively connecting this capacitor in series between the terminals of the submodule or to bypass it. The submodules are controlled in a sequence chosen to gradually vary the number of energy storage elements which are connected in series in a half-arm of the converter 2 so as to provide several voltage levels. In addition, in FIG. 1, κ / c denotes the voltage at the connection points of the converter to the continuous power supply network, these points being covered by the common English expression "PCC: Point of Common Coupling", which is well known. those skilled in the art, idc designates the current of the continuous power supply network, while currents iga, igt, and igc cross the three phase lines cpa, cpb, and cpc. In addition, each half-arm has an inductance Urm and each phase line has an inductance Z ^ and a resistor Rf.
    FIG. 2 illustrates a sub-module SMxij according to the prior art belonging to the converter of FIG. 1. In this submodule, each control member comprises a first electronic switching element T1 such as a bipolar transistor with insulated gate ( "IGBT: Insulated Gate Bipolar Transistor" connected in series with a storage element of electrical energy, here a capacitor CSM. This first switching element T1 and this capacitor CSM are connected in parallel with a second electronic switching element T2, also an insulated gate bipolar transistor (IGBT). This second switching element T2 is coupled between the input and output terminals of the submodule SMxij. The first and second switching elements T1 and T2 each have an antiparallel diode shown in FIG.
    In operation, the submodule can be controlled in two control states.
    In a first state said state "on" or controlled, the first switching element Tl is open, and the second switching element T2 is closed, for connecting the energy storage element CSMen series with the other submodules. In a second state called "off" or non-controlled state, the first switching element T1 is closed, and the second switching element T2 is open so as to bypass the energy storage element.
    It is known that each half-arm, having a voltage vm at its terminals, can be modeled by a modeled voltage source, having a voltage vm at its terminals, whose duty cycle depends on the number of sub-modules controlled and by a capacitor Ctot modeled connected to the voltage source. This modeling has been schematized in Figure 3, on which we see a half-arm and modeling obtained. The capacitance value of the modeled capacitor Ctot is equal to the sum of the inverse of the capacitances of the controlled submodules, so that:
    where Ci, C2, ..., (Γ / v) are the capacitances of the jth capacitor.
    Thus, the voltage vcE across the capacitor Ctot modeled is equal to the sum of the voltages vcj across the capacitors of the submodules in the half-arm (with j ranging from 1 to N and indicating the number of the capacitor and therefore the sub -module). In the present application, by misnomer, Ctot refers to both the capacitor and its capacitance value. By controlling the control sequence of the sub-modules to gradually vary the number of energy storage elements connected in series, the energy of the modeled capacitor Ctot and therefore the voltage across each modeled voltage source can be decreased. or increased.
    In the prior art, there is therefore an equivalent configuration of the set 6 of the submodules of the MMC converter illustrated in FIG.
    In this figure, the converter is a converter analogous to that described with reference to FIG. 1, and in which each half-arm has been replaced by its modeling. In addition, each phase line is associated with a current igiet a voltage vgi (i indicating the number of the arm).
    Here, each of the modeled voltage sources comprises at its terminals a voltage v ^ and each modeled capacitor Ctot has at its terminals a voltage vcZxi (with x indicating whether the half-arm is greater or less and i indicating the arm number). It can furthermore be noted that it is possible to decompose the MMC converter into an imaginary alternating part and an imaginary continuous part (at the input or at the output, depending on whether the converter is configured to convert an alternative energy into continuous energy or vice versa ), where the evolution of the total energy stored in the capacitors of the submodules is equal to the difference between the power entering the converter and the outgoing power.
    Voltage Source Converter converters are known (well known to those skilled in the art by the acronym "VSC"), having a station capacitor connected in parallel with the DC power supply network. The disadvantage of such a capacitor in parallel is that it does not allow decoupling of the converter with the voltage of the DC power supply network. In addition, this type of converter requires the use of numerous filters to obtain suitable converted signals.
    In addition, the inertia of the continuous power supply network depends on its capacity, so that a large capacity increases the inertia of the continuous power supply network. Thus, a large capacity of the network and therefore a high inertia allows it to better withstand disturbances. Conversely, a low network capacity, and therefore a low inertia makes it possible to regulate more easily and more precisely the voltage at the connection points of the converter to the DC power supply network.
    However, unlike Voltage Source Converter type converters, the MMC converters do not include a station capacitor connected in parallel and can affect the stability of the DC power supply network. Multilevel modular converters thus have the advantage of offering a decoupling between the total voltage of the capacitors of the submodules and the voltage of the continuous power supply network. Nevertheless, a simple power variation could lead to a large voltage variation of the continuous power supply network.
    There are known MMC converters whose control is not based on energy ("Non Energy Based Control" in English). In these converters, when a potential difference in voltage appears between the voltage of the capacitors of the half-arms and the voltage of the DC power supply network, the power of the incoming DC power supply network automatically varies to correct said voltage difference. . This control is carried out without additional regulator since the exchanges of energies with the capacitors of the half-arms follow the variations of voltage on the continuous power supply network.
    However, not all variables of this type of converter are controlled, which results in a lack of robustness of the converter.
    It is also known converters whose control is based on energy. The document entitled "Control of DC bus voltage with a Modular Multilevel Converter" (Samimi et al., PowerTech conference, 2015), which presents a multi-level modular converter including a system for controlling power transfer at the level of the alternative part, transfers of power at the level of the continuous part and the internal energy of the converter. Such a converter uses a control based on energy ("Energy Based Control" in English): a control of the current variables of the DC and AC power supply networks allows to control the powers of these two respective networks. A difference between the powers of the DC and AC power networks causes a decrease or increase of the energy stored in the capacitors of the submodules. This type of converter, however, damages the decoupling between the voltages at the terminals of the submodule capacitors and the voltage of the continuous power supply network. In addition, it does not allow to adapt effectively and in real time to voltage fluctuations on the continuous power supply network.
    In addition, the known converters are not sufficiently robust, in particular with regard to the contribution to the stability of the DC power supply network.
    In particular, the control of the internal energy is an additional degree of freedom, but no existing technique offers a solution to effectively regulate the internal energy of the converter.
    Existing solutions do not fully exploit the capabilities of MMC converters in terms of control of the internal energy of the converter together with the control of the stability of the DC network.
    Object and summary of the invention
    An object of the present invention is to propose a multi-level modular converter (MMC) equipped with a converter control module which makes it possible to fully exploit the potential of the MMC converter by offering a better interaction between the internal energy of the converter. , stored in the submodule capacities, and the voltage of the continuous power supply network. Another advantage of the converter is to allow the converter to act more effectively on the inertia of the continuous power supply network.
    To do this, the invention relates to a multi-level modular voltage converter, for converting an alternating voltage into a DC voltage and vice versa, comprising a so-called continuous portion intended to be connected to a DC power supply network and a said alternative portion intended to be connected to an alternating electrical supply network, the converter comprising a plurality of arms, each arm comprising an upper half-arm and a lower half-arm, each half-arm comprising a plurality of sub-modules controllable individually by a control member specific to each submodule and each submodule comprises a capacitor connectable in series in the half-arm when the control member of the submodule is in a controlled state, each half-arm can be modeled by a modeled voltage source associated with a duty cycle depending on a number of capacitors connected in series of in the half-arm, each modeled voltage source being associated in parallel with a modeled capacitor (corresponding to a total capacity of the half-arm).
    The converter further comprises a converter control module configured to regulate the voltage across each modeled capacitor of each arm and to regulate the voltage at the connection points of the converter to the DC power supply network by controlling said control means of sub-modules of the converter.
    According to a general characteristic of the converter, the control module of the converter comprises a calculator of an internal energy value of the converter stored in the capacities of the submodules of the half-arms by application of a function having an input parameter. adjustable, the control module being configured to derive from this energy setpoint a voltage setpoint at the terminals of each modeled capacitor used to regulate the voltage at the connection points of the converter to the DC power supply network and the voltage at the terminals of each capacitor modeled.
    The input parameter of the calculator can be set at any time and easily by the user. Since the internal energy setpoint of the converter depends on the input parameter, it is possible for the user to act directly on the degree of contribution of the internal energy to the stability of the continuous power supply network. The user can therefore adjust the input parameter according to the disturbances of the continuous power supply network and increase or decrease the inertia of the network as needed.
    In a nonlimiting manner, the contribution to the power supply network of the multi-level modular converter, whose control module is provided with such a computer, is equivalent to that of a virtual capacitor disposed in parallel with the power supply network. continuous power supply. By adjusting the adjustable input parameter of the computer, the capacity of the virtual capacitor is virtually varied. The interest is to be able to act on the continuous power supply network while maintaining the decoupling between the total voltage of the sub-module capacitors and the voltage of the continuous power supply network.
    Unlike a capacitor actually placed in parallel with the continuous power supply network, the virtual capacitor makes it possible to stabilize the network, has no cost and can not be degraded. In particular, an adjustable virtual capacitor can take very high capacitance values, which is not physically possible for a real capacitor.
    Preferably, the submodules are controlled by means of two insulated gate bipolar transistors (IGBT) enabling the capacitor of said submodule to be placed in series or not in series in the associated half-arm according to which it is desired to control the submodule in the commanded state "on" or in the non-commanded state "off".
    Each half-arm can be modeled by a modeled voltage source associated in parallel with a modeled capacity capacitor Ctot. Note the sum of the voltages of the capacitors of the sub-modules of a half-arm, so that the voltage across the parallel modeled capacitor associated with the modeled voltage source is vcl.
    Preferably, the duty cycle a, associated with the modeled voltage source, is calculated from the expression: n a = -
    Where n is the number of sub-modules connected to the "on" state in the associated half-arm and N is the number of submodules in the half-arm.
    By jointly controlling the voltage at the connection points of the converter to the DC power supply network and the voltage at the terminals of each modeled capacitor, and therefore the internal energy of the converter, it is possible to act on the stability of the continuous power supply network. .
    This makes it possible to contain any power disturbances appearing suddenly on the DC power supply network and which could cause significant voltage variations on said network.
    In a nonlimiting manner, the joint regulation of the voltage at the connection points of the converter to the DC power supply network and the voltage across the terminals of each modeled capacitor can be done by closed-loop control of these quantities by means of values of setpoints, in particular a voltage setpoint at the connection points of the converter to the continuous power supply network. The control module is said to be "slow" as opposed to other control elements that can be controlled and whose switching times are very short.
    In addition, the voltage setpoint v * cE at the terminals of each modeled capacitor, squared, is proportional to the internal energy setpoint uc delivered by the computer according to the expression:
    Said internal energy setpoint of the converter and therefore said voltage setpoint at the terminals of each capacitor, squared, allow to enslave the voltage of the DC power supply network and the voltage across each capacitor modeled.
    Advantageously, the adjustable input parameter is an adjustable virtual inertia coefficient kvi. Modifying kvi thus amounts to virtually modifying the size of the capacitance of the virtual capacitor and thus contributing to the stability of the continuous power supply network. The advantage is to provide an additional degree of freedom in controlling the internal energy of the MMC converter. The capacity of the virtual capacitor can in particular take very high values without additional hardware constraints.
    Preferably, the computer is configured to calculate the internal energy setpoint of the converter according to the function:
    where Qi is a total capacitance of the modeled capacitor, vdc is a measured voltage of the continuous power supply network, vdco is a nominal value of the voltage of the DC power supply network and W £ 0 is a nominal value of the value of the DC power supply. energy stored in the capacitors of the converter.
    We understand that the capacitance CVi of the virtual capacitor is expressed:
    In addition, the term (v ^ c - v ^ c0) represents a voltage difference on the DC power supply network, reflecting a voltage disturbance. It is therefore noted that by acting on the adjustable virtual inertia coefficient kvi, it is possible to act on the variation of the voltage at the connection points of the converter to the DC power supply network.
    Preferably, the control module comprises a regulator of the internal energy of the converter having as input the result of a comparison between said voltage setpoint at the terminals of each modeled capacitor, squared, and a mean of the square of the voltages at the terminals of the capacitors modeled, and delivering a power setpoint for the capacitors of said converter.
    Thanks to the internal energy regulator, it is therefore possible to control the voltage across the terminals of each modeled capacitor, squared, from a setpoint value of this voltage. Since the voltage at the terminals of each modeled capacitor, squared, is proportional to the internal energy of the converter stored in the capacitors of the sub-modules of the half-arms, the voltage across the terminals of each capacitor modeled from the internal energy setpoint of the converter stored in the capacitors of the sub-modules of the half-arms provided by the computer.
    Advantageously, the control module is configured to perform a variable change in order to control intermediate variables of current idUf and igdet of voltage vdiffet vgdl where idiff and vdlff are associated with the continuous power supply network and igdet i ^ are associated with the network alternative power supply.
    Intermediate variables of current idiff and igd can be controlled independently.
    In a non-limiting way, in the case of a continuous energy converter in alternative energy, these variables make it possible to express the variation of internal energy of the converter in the form:
    This expression translates in particular the decomposition of the MMC converter into a continuous input imaginary part, connected to the continuous network and associated with the term Ef = 12idi //. vdiff which corresponds to the power of the continuous part and an alternative imaginary part in output, connected to the alternative network and associated to the term igdVgd which corresponds to the power of the alternative part.
    Preferably, the control module comprises a current regulator / paying input a set i * d corresponding to the current igd. The regulator slaves the current igd by making it tend towards its setpoint i * d. The regulation of the igd variable amounts to regulating the input or output AC power transfers according to the configuration of the converter.
    Preferably, the control module comprises an idiff current regulator having an input l * diff corresponding to the current idiff. The regulator slaves the current Wen making it tend towards its idiff setpoint. The regulation of the variable idiff amounts to regulating the transfers of continuous power input or output according to the configuration of the converter.
    In a nonlimiting manner, the variables igd and idiff can be controlled independently. It is then understood that regulating igd and idiff makes it possible to regulate the transfers of incoming and outgoing powers, and
    thus controlling the internal energy of the converter stored in the capacitors of the submodules.
    According to a particularly advantageous aspect of the invention, the control module comprises a regulator of the voltage at the connection points of the converter to the DC power supply network having as input the result of a comparison between a voltage setpoint at the points of connection of the converter to the continuous power supply network, squared, and a value taken from the DC power supply also squared, and delivering an operating power setpoint of said converter.
    Thanks to this regulator, it is therefore possible to control the voltage at the connection points of the converter to the DC power supply network Vdc by making its value, squared, stretch towards the voltage set point at the connection points of the converter to the power supply network. DC power supply v * dc, squared.
    Preferably, the control module comprises a member for adjusting the gain of the voltage regulator at the connection points of the converter to the DC power supply network, as a function of the value of the virtual inertia coefficient kVi. Indeed, when the virtual inertia coefficient kvi is set, in order to modify the degree of contribution of the converter's internal energy to the stability of the continuous power supply network, the overall inertia of the MMC converter is modified. . This has the effect of disrupting the operation of the voltage regulator at the connection points of the converter to the DC power supply network.
    In particular, the adjustment of the virtual coefficient of inertia has the consequence of modifying a time constant τ associated with said regulator of the voltage at the connection points of the converter to the DC power supply network. The member for adjusting the gain of the voltage regulator thus makes it possible to correct the deviations on the time constant and on the gain of the voltage regulator, introduced by the modification of the virtual inertia coefficient kvi, so as to calibrate said regulator Of voltage.
    In addition, the member for adjusting the gain of the voltage regulator at the connection points of the converter to the DC power supply network receives as input the virtual coefficient of inertia kvi so as to adjust the gain in real time, depending on the changes made to the kvi-
    Advantageously, the control module comprises a limiter of the internal energy of the converter having as input the internal energy of the converter, a maximum internal energy value of the converter and a minimum internal energy value of the converter, and delivering a limitation power setting. The advantage is to be able to contain the internal energy of the converter between the maximum internal energy setpoint values of the converter W ^ iim and the minimum internal energy setpoint of the converter W £ lim, defined by the operator. By keeping the internal energy of the converter between these maximum and minimum setpoint values, particular protection is provided for the electronic switching elements, such as the transistors. Without this protection, the switching elements can be threatened by too high a voltage across the capacitors of the submodules, while too low voltages across the capacitors of the submodules could affect the operation of the MMC converter.
    In particular, the limiting power setpoint delivered by the limiter is added to the operating power setpoint of the converter to give the power setpoint of the AC power supply network and thus regulate the internal energy level of the converter. However, the limiting power appears as a disturbance on the control of the energy. This is why it is necessary to correct the nominal setpoint of the value of the energy stored in the capacitors of the converter which is supplied to the calculator of the internal energy setpoint, for example by means of an integral corrector. The invention also relates to a method for controlling a multi-level modular voltage converter, the converter making it possible to convert an alternating voltage into a DC voltage and vice versa, and comprising a so-called continuous portion intended to be connected to a DC power supply network. DC power supply and an so-called alternative portion intended to be connected to an AC power supply network, the converter comprising a plurality of arms, each arm comprising an upper half-arm and a lower half-arm, each half-arm comprising a plurality of sub-modules individually controllable by a submodule control member and comprising a capacitor connected in series in the half-arm in a controlled state of the sub-module control member, each half-arm being Modeled by a modeled voltage source associated with a duty cycle depending on a number of capacitors put in series in the half-arm, each modeled voltage source being associated in parallel with a modeled capacitor corresponding to a total capacitance of the half-arm, the method furthermore comprising a slow control of the converter in which the voltage across the terminals of each capacitor is regulated modeled from each arm and the voltage is regulated at the connection points of the converter to the DC power supply network by controlling said control elements of the submodules of the converter.
    In a characteristic way, the method comprises a calculation of an internal energy setpoint of the converter stored in the capacities of the sub-modules of the half-arms by using a function having an adjustable input parameter, and a calculation of a setpoint of voltage at the terminals of each capacitor modeled from said internal energy setpoint of the converter, the voltage setpoint at the terminals of each modeled converter being used to regulate the voltage at the connection points of the converter to the DC power supply network and the voltage across each capacitor modeled.
    According to one variant, the adjustable input parameter is an adjustable virtual inertia coefficient kVi.
    According to one variant, the calculation of the internal energy setpoint of the converter is carried out according to the function:
    where Ctot is the total capacitance of the capacitor modeled in a half arm, Vot is the measured voltage of the DC power supply, Vdco is the nominal value of the voltage at the connection points of the converter to the DC power supply and W ^ 0 is a nominal setpoint of the value of the energy stored in the capacitors of the converter.
    According to one variant, the control method comprises a regulation of the voltage at the connection points of the converter to the DC power supply network by using as input the result of a comparison between a voltage setpoint at the connection points of the converter to the network. continuous power supply, squared, and a value taken from the DC power supply also squared, and delivers an operating power setpoint of said converter.
    According to one variant, the control method comprises an adjustment of the regulation gain of the voltage at the connection points of the converter to the continuous power supply network, as a function of the value of the virtual coefficient of inertia.
    This method can implement the various embodiments of the converter as described above.
    The invention also relates to a control module for a multi-level modular converter as defined above, and comprising a calculator of an internal energy setpoint of the converter stored in the capacities of the sub-modules of the half-arms. by applying a function having an adjustable input parameter. In addition, the control module is configured to deduce from this energy setpoint a voltage setpoint across each modeled capacitor used to regulate the voltage at the connection points of the converter to the DC power supply and the voltage across the terminals. of each modeled capacitor.
    BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood on reading the following description of an embodiment of the invention given by way of non-limiting example, with reference to the appended drawings, in which: FIG. 1 , already described, illustrates a multi-level modular converter with three phases according to the prior art; FIG. 2, already described, illustrates a submodule of a multi-level modular converter according to the prior art; FIG. 3, already described, illustrates a half-arm equivalent circuit of a MMC converter according to the prior art; FIG. 4, already described, shows an equivalent configuration of a multi-level modular converter according to the prior art; FIG. 5 illustrates an equivalent and schematic representation of a multi-level modular converter according to the invention; FIG. 6 illustrates a multi-level modular converter provided with a control module according to the invention; FIG. 7 shows an exemplary implementation of the adjustment of the regulator of the voltage at the connection points of the converter to the continuous power supply network; FIG. 8 shows a simplified loop of adjustment of the regulator of the voltage at the connection points of the converter to the continuous power supply network; FIG. 9A shows a power level imposed on an AC network for simulating the operation of the converter according to the invention; FIG. 9B illustrates the voltage response of a continuous network at a power level over an AC network as a function of time for different values of kVi; FIG. 9C illustrates the variation of the total energy of a converter in response to a power step on an AC network, as a function of time, for different values of k / i; FIG. 9D illustrates the response of the power of a continuous network to a power level over an AC network as a function of time for different values of kVi; FIG. 10A illustrates the voltage response of a continuous network for a first simulation system consisting of an MMC converter comprising a virtual capacitor according to the invention and for a second simulation system consisting of a converter according to the prior art equipped with a real capacitor in parallel of the continuous network; FIG. 10B shows the variations of the total energy of the converter for the two simulation systems; FIG. 10C shows the power response on the alternating network of the two simulation systems; FIG. 10D shows the power response on the continuous network of the two simulation systems; and FIG. 11 shows an MMC converter according to the invention in which the control module is provided with a limiter for the internal energy of the converter.
    DETAILED DESCRIPTION OF THE INVENTION The invention relates to a multi-level modular converter provided with a control module, a circuit of which the equivalent behavior is illustrated in FIG. 5. In this figure, in a nonlimiting manner, there is shown a MMC 2 converter of continuous energy into alternative energy. In this example, it will be noted that this converter 2 comprises an alternative part 2A, connected to the AC power supply 110, in the left part of the diagram. In the right part of the diagram, it can be seen that the converter 2 comprises a continuous portion 2C connected to the continuous power supply network 120.
    It can be seen that a virtual capacitor Cvi of adjustable capacitance Cvi (by misuse of language and for the sake of simplicity, the same notation is used to designate the capacitor and its capacitance) is associated in parallel with the continuous power supply network. 2C. By virtual means that this capacitor is not really present in the converter. On the other hand, the control module according to the invention makes it possible to obtain a converter operation analogous to that of a converter equipped with this virtual capacitor: this virtual capacitor Cvi expresses the behavior of the converter 2 and its control module 4 according to the invention. Indeed, by adjusting a virtual coefficient of inertia kVIl improves the stability of the continuous power supply network 120 and the behavior of the converter is similar to that of a converter in which a virtual capacitor Cvi of adjustable capacity Cvi is placed in parallel of the continuous power supply network 120.
    The diagram of FIG. 5 also illustrates the power transfers between the converter 2 and the DC and AC power supply networks 120 and 110. Thus, Pi is the power coming from other stations of the continuous power supply network and symbolizes a sudden disruption in power on the continuous network, Pdc is the power extracted from the continuous electrical supply network 120, Pac is the power transmitted to the AC power supply network 110, Pc is the power absorbed by the capacitor Cdc of the power supply network. 120 continuous power supply, Pm is the operating power of the converter 2 and Pw can be considered as the power absorbed by the virtual capacitor Cvi adjustable capacity Cvi. In addition vdc is the voltage at the connection points of the converter to the DC power supply.
    In the MMC converter 2 according to the invention, and unlike a prior art MMC converter, a surplus of the power of the continuous power supply network 120, denoted by PWI, is absorbed by the virtual capacitor CVi and enables the converter to store WE internal energy. The example of FIG. 6 illustrates a multilevel modular converter 2 equipped with a control module 4 according to the invention. The converter MMC is configured to regulate, by closed-loop servocontrol, the voltage at the connection points of the converter to the continuous power supply network 120 i and the voltage νοΣ at the terminals of each modeled capacitor.
    The control module 4 comprises a computer 10 which calculates an internal energy setpoint W £ of the converter 2 stored in the sub-module capacities of the half-arms from an adjustable virtual inertia coefficient kVi, a nominal setpoint of the value of the energy stored in the capacitors of the converter νΣ0ι a measured voltage of the DC power supply network i ^ and a nominal value of the voltage at the connection points of the converter to the network d DC power supply VdCo- According to the diagram of Figure 5, we see that:
    where Wdc is the energy of the continuous power supply network.
    Still in FIG. 5, assuming that Pm is equal to Paci, we also find that:
    where Ctofest the capacitance of the capacitor modeled in a half arm.
    By combining the two previous equations we arrive at the following expression:
    This expression notably shows that by controlling the internal energy Wz of the MMC converter, the power Pt-Pm can be distributed between the capacitance Cdc of the continuous power supply network and the capacities of the sub-modules of the half-arms.
    The calculator calculates the appropriate internal energy setpoint according to the function:
    Said internal energy setpoint of the converter makes it possible to supply a voltage setpoint ν * Σ at the terminals of each modeled capacitor. This voltage setpoint ν * Σ at the terminals of each modeled capacitor, squared, is itself compared with a mean of the square of the voltages at the terminals of the modeled capacitors.
    Without departing from the scope of the invention, the average can be calculated in any way. In the non-limiting example illustrated in FIG.
    6, the average is calculated as the sum of the squared capacitor voltages modeled in each half-arm, divided by six (the converter having six half-arms). Said comparison is provided to an internal energy regulator of the converter 20 which delivers a power setpoint p £ for the capacitors of said converter 2.
    Moreover, considering that the regulation of the energy is fast enough, one obtains:
    or :
    We can therefore express the virtual inertia coefficient k / j in the form:
    This expression shows that by adjusting the virtual inertia coefficient kvion manages to modify the value of the virtual capacitance Cvi.
    In FIG. 6, it is also noted that the control module 4 comprises a voltage regulator 30 at the connection points of the converter to the DC power supply network 120, having as input the result of a comparison between a voltage setpoint at the connection points of the converter to the DC power supply network v * dc, squared, and a value taken from the DC power supply network vdc, also squared. The regulator 30 of the voltage at the connection points of the converter to the DC power supply network 120 delivers an operating power setpoint P p of the converter 2.
    In addition, the control module 4 comprises an AC current regulator igd 40 having as input a setpoint i * gd, and a current regulator / ^ 50 having as input a setpoint
    From Figure 3, it is known that it is possible to model the sub-modules of a half-arm by a modeled voltage source associated in parallel with a modeled capacitor so that the modeled voltage sources have at their terminals a voltage vmxi (with x indicating whether the half-arm is upper or lower and i indicating the arm). The current regulators 40 and 50 deliver voltage setpoints vdiff and vJ used following a change of variable, by a modulation element 60 and two balancing elements 70a and 70b by means of a control algorithm ("BCA: Balancing Control Algorithm in English), to deliver voltages across modeled voltage sources. This makes it possible to control or not the submodules of the half-arms. This controls the voltage across the capacitors modeled vcixi and the voltage at the connection points of the converter to the DC power supply network vdc.
    By varying the virtual inertia coefficient kvi at the input of the computer can therefore directly influence the voltage of the DC power supply network vdc and the inertia of this continuous network.
    In this nonlimiting example, the control module 4 also comprises a member 100 for adjusting the gain of the voltage regulator at the connection points of the converter to the continuous power supply network 120, as a function of the value of the coefficient of inertia virtual kVi. This element has, for reasons of simplicity, been represented outside the control module 4, although it is included in this control module 4.
    Figure 7 shows an example of adjusting the voltage regulator at the connection points of the converter to the DC power supply network vdc using a Proportional Integral Corrector (PI) on the servo loops of vdc and from W £. In this non-limiting example, the PI corrector is adjusted by a conventional method of placing the poles.
    This circuit comprises in particular loops 42 and 52 for regulating currents W and their respective instructions idiff and i * d.
    For simplification, it is possible to obtain an equivalent representation of the voltage regulation loop at the connection points of the converter to the continuous power supply network 120 with adjustment of the regulator of said voltage at the connection points of the converter to the continuous network at the using a PI corrector. Such a representation is given in FIG.
    FIGS. 9A to 9D show the results of a simulation of the behavior of a multi-level modular converter 2 provided with a control module 4 according to the invention and in particular a simulation by power control. In this simulation, a test system was created in which the DC portion of the converter is connected to an ideal DC power source, simulating a DC power supply network 120, while the converter AC portion is connected to a source. alternating power, simulating an AC power supply network 110. A power step is then imposed on the simulated AC grid, the virtual inertia coefficient kVi is varied and the results are observed on the other quantities of the system.
    As can be seen in FIG. 9A, the curve represents a power step of 0.03 pu, imposed at the level of the simulated alternating network for 0.1 seconds, before bringing the AC power back to its initial zero value. This behavior simulates a transfer of active power from the MMC converter 2 to the AC power supply 110.
    The simulated DC network voltage response for different kVI values is shown in FIG. 9B. Each of the curves corresponds to a value of kvi so that the curves a, b, c, te correspond to respective values of ky / equals at 0, 0.5, 1, 2 and 3. Note that more kVI is higher. the variations on the simulated continuous network are small. This is in keeping with the principle of the invention, since increasing the kVi increases the inertia of the converter, which allows the continuous network to further contain the disturbances and stabilize the voltage of the continuous network.
    FIG. 9C illustrates the variation of the total energy of the converter for several kVi values. The curves g, h, i, j and k correspond to respective values of kVI equal to 0, 0.5, 1, 2 and 3. By increasing the virtual inertia coefficient kVi, the value of the virtual capacitance is increased which implies that the contribution of the energy of the converter is greater and that more energy is extracted from the virtual capacitor. This increase in the contribution of the energy of the converter therefore results in a decrease of the total energy of the converter when the virtual coefficient of inertia is increased.
    The consequence is visible in FIG. 9D, representing the evolution of the power on the simulated continuous network as a function of the values of the virtual inertia coefficient kVi. Here, the curves m, n, o, p and q correspond to respective values of regales at 0, 0.5, 1, 2 and 3. It can be seen that when the virtual coefficient of inertia kVi increases, the impact on the power of the simulated continuous network, the power variation of the simulated alternative grid is less. In particular, less energy is extracted from the capacitors of the continuous power supply network. This is because more energy is extracted from the virtual capacitor. Virtual capacity helps to stabilize and improve the inertia of the continuous network.
    FIGS. 10A to 10D illustrate a simulation by controlling the voltage at the connection points of the converter to the continuous network, in which the behavior of two systems is compared. The first system consists of a modular multi-level converter according to the invention, configured as in the previous simulation. The virtual inertia coefficient is set and set so that kVi = 1. The second system consists of a MMC converter according to the prior art, whose continuous part is also connected to an ideal continuous power source, while the part converter alternative is connected to an AC voltage source. In this second system, a real capacitor is arranged in parallel with the simulated continuous network. The value of the capacitance of this real capacitor is chosen equal to the capacitance of the virtual capacitor Cvi of the first system. It is therefore a question of comparing the influence of a virtual capacitor Cvi and of a real capacitor associated with an MMC converter, in parallel with a simulated continuous network.
    A power perturbation step is imposed by the DC power source on both systems as can be seen in the dotted curve z of FIG. 10D.
    In FIG. 10A, the curves r and 5 respectively represent revolution of the simulated DC voltage for the first and second systems. It can be seen that the evolution of the simulated DC voltage is the same for both systems.
    Since both systems are configured so that the values of the real and virtual capacities are equal, the response of the simulated AC grid power is the same for both systems. This response is represented in FIG. 10C by the curve v, while the curve w represents the power perturbation step on the simulated continuous network.
    FIG. 10B illustrates, through the curve t, an increase in the total energy in the case of the first system, provided with a virtual capacitance, translating the energy stored in the virtual capacitor. On the other hand, on the second system represented by the curve u, no variation of the total energy is observed since, for this converter, there is no contribution of the internal energy on the simulated continuous network. .
    In FIG. 10D, according to the curves y and x, respectively representing the power of the simulated continuous network for the first and the second system, it can be seen that the presence of a virtual capacitance improves the power response to a power perturbation. on the simulated continuous network represented by the curve z. The disturbance therefore has less impact on the simulated continuous network and the power of said continuous network is better controlled.
    A variant of the converter according to the invention is illustrated in FIG. 11, in which the control module comprises an energy limiter 80 receiving as input the internal energy WE of the converter, a maximum internal energy setpoint of the converter W ^ lim and a minimum internal energy setpoint of the converter W ^ um. The energy limiter 80 delivers a limitation power setpoint PEL associated with a limiting power Pel- This energy limiter limits the internal energy WE between the maximum and minimum internal energy setpoint values of the converter.
    The limiting power Pel appears as a disturbance on the control of the energy. The nominal setpoint W ^ 0 of the value of the energy stored in the capacitors of the converter is thus corrected in order to supply the calculator 10 with the internal energy setpoint, a corrected nominal setpoint W £ q of the value of the energy stored in the capacitors.
    We now have:
    so that :
    In addition, the corrected nominal setpoint W £ q of the value of the energy stored in the capacitors is expressed:
    Substituting in the preceding equations we obtain:
    Is :
    It can therefore be seen that the energy limiter 80 does not modify the behavior of the converter within the maximum and minimum internal energy limits. The behavior of the converter is similar to that of a converter in which a virtual capacitor CVi of adjustable capacity Cvi is placed in parallel with the continuous power supply network 120.
    权利要求:
    Claims (16)
    [1" id="c-fr-0001]
    A multilevel modular voltage converter (2) for converting an alternating voltage to a DC voltage and vice versa, comprising a so-called DC portion (2C) for connection to a DC power supply (120) and an so-called alternative portion (2A) intended to be connected to an AC power supply (110), the converter comprising a plurality of arms, each arm comprising an upper half-arm and a lower half-arm, each half-arm comprising a plurality of sub-modules individually controllable by a control member specific to each submodule and each submodule comprises a capacitor connectable in series in the half-arm when the sub-module control member is in a state controlled, each half-arm can be modeled by a modeled voltage source associated with a duty cycle dependent on a number of capacitors placed in series in the half -bras, each modeled voltage source being associated in parallel with a modeled capacitor corresponding to a total capacity of the half-arm, the converter further comprising a converter control module configured to regulate the voltage across each modeled capacitor of each arm and for regulating the voltage at the connection points of the converter to the DC power supply network by controlling said control elements of the submodules of the converter, characterized in that the control module of the converter comprises a computer (10) of an internal energy setpoint of the converter stored in the submodule capacities of the half-arms by application of a function having an adjustable input parameter, the control module being configured to deduce from this energy setpoint a setpoint voltage across the terminals of each modeled capacitor used to regulate the voltage at the points of connection of the converter to the DC power supply and the voltage across each capacitor modeled.
    [2" id="c-fr-0002]
    2. Converter according to claim 1, wherein the adjustable input parameter is an adjustable virtual inertia coefficient kVi.
    [3" id="c-fr-0003]
    3. Converter according to claim 2, wherein the computer (10) is configured to calculate the internal energy setpoint of the converter according to the function:

    where Qot is the total capacitance of the modeled capacitor in a half-arm, v ± is the measured voltage of the DC power supply, Vdco is the nominal value of the voltage at the connection points of the converter to the DC power supply and W ^ 0 is a nominal setpoint of the value of the energy stored in the capacitors of the converter.
    [4" id="c-fr-0004]
    4. Converter according to any one of claims 1 to 3, wherein the control module comprises a regulator (20) of the internal energy of the converter having as input the result of a comparison between said voltage setpoint across the terminals. each capacitor modeled, squared, and an average of the square of the voltages across the capacitors modeled, and delivering a power setpoint for the capacitors of said converter.
    [5" id="c-fr-0005]
    The converter according to any one of claims 1 to 4, wherein the control module is configured to perform a variable change to control intermediate variables of current idiff and / ^ and voltage Vd ^ and vgd, where and Vdiff are associated with the DC power supply and igd and i ^ are associated with the AC power supply.
    [6" id="c-fr-0006]
    6. Converter according to claim 5, wherein the control module comprises a regulator (40) of the current / paying input a set i * gd corresponding to the current igd.


    [7" id="c-fr-0007]
    7. Converter according to any one of claims 5 or 6, wherein the control module comprises a regulator (50) of the idiff current having as input a reference l * aiff corresponding current idiff.
    [8" id="c-fr-0008]
    8. Converter according to any one of claims 1 to 7, wherein the control module comprises a regulator (30) of the voltage at the connection points of the converter to the DC power supply network having as input the result of a comparison between a voltage setpoint at the connection points of the converter to the continuous power supply network, squared, and a value taken from the DC power supply also squared, and delivering an operating power setpoint of said converter.
    [9" id="c-fr-0009]
    The converter according to claims 2 and 8, wherein the control module comprises a member (100) for adjusting the gain of the regulator (30) of the voltage at the connection points of the converter to the continuous power supply network, depending the value of the virtual inertia coefficient kvi.
    [10" id="c-fr-0010]
    10. Converter according to any one of claims 1 to 9, wherein the control module comprises a limiter of the internal energy of the converter having as input the internal energy of the converter, a maximum internal energy value of the converter and a minimum internal energy setpoint of the converter, and delivering a limiting power setpoint.
    [11" id="c-fr-0011]
    11. A method for controlling a multilevel modular voltage converter, the converter for converting an alternating voltage into a DC voltage and vice versa, and comprising a so-called continuous portion intended to be connected to a DC power supply network and a part said alternative intended to be connected to an AC power supply network, the converter comprising a plurality of arms, each arm comprising an upper half-arm and a lower half-arm, each half-arm comprising a plurality of controllable submodules individually by a submodule control member and comprising a capacitor connected in series in the half-arm in a controlled state of the submodule control member, each half-arm being modelable by a modeled voltage source associated with a duty cycle dependent on a number of capacitors placed in series in the half-arm, each source modeled voltage corresponding in parallel to a modeled capacitor corresponding to a total capacitance of the half-arm, the method furthermore comprising a slow control of the converter in which the voltage across the terminals of each modeled capacitor of each arm is regulated and the voltage at the connection points of the converter to the DC power supply network by controlling said control elements of the submodules of the converter, characterized in that it comprises a calculation of an internal energy setpoint of the converter stored in the capacitors sub-modules of the half-arms using a function having an adjustable input parameter, and a calculation of a voltage setpoint across each capacitor modeled from said internal energy setpoint of the converter, the setpoint of terminal voltage of each modeled converter being used to regulate the voltage at the connection points of the inverter to the DC power supply network and the voltage across each capacitor modeled.
    [12" id="c-fr-0012]
    12. The method of controlling a converter according to claim 11, wherein the adjustable input parameter is an adjustable virtual inertia coefficient kVi.
    [13" id="c-fr-0013]
    13. The method of controlling a converter according to claim 12, wherein the calculation of the internal energy setpoint of the converter is carried out according to the function:



    where Ctot is the total capacitance of the capacitor modeled in a half-arm, vdc is the measured voltage of the DC power supply network, vdco is the nominal value of the voltage at the connection points of the converter to the DC power supply and W ^ 0 is a nominal setpoint of the value of the energy stored in the capacitors of the converter.
    [14" id="c-fr-0014]
    14. A method of controlling a converter according to any one of claims 11 to 13, comprising a regulation of the voltage at the connection points of the converter to the DC power supply network using as input the result of a comparison between a voltage setpoint at the connection points of the converter to the continuous power supply network, squared, and a value taken from the DC power supply also squared, and delivering an operating power setpoint of said converter.
    [15" id="c-fr-0015]
    15. A method of controlling a converter according to any one of claims 11 to 14, comprising an adjustment of the voltage regulation gain at the connection points of the converter to the DC power supply network, depending on the value of the virtual inertia coefficient.
    [16" id="c-fr-0016]
    16. Control module for a multi-level modular converter according to any one of claims 1 to 10, characterized in that it comprises said computer (10) an internal energy set of the converter stored in the capabilities of the sub-modules of the half-arms by applying a function having an adjustable input parameter, and in that it is configured to derive from this energy setpoint a voltage setpoint at the terminals of each modeled capacitor used to regulate the voltage at the connection points of the converter to the DC power supply network and the voltage across each capacitor modeled.
    类似技术:
    公开号 | 公开日 | 专利标题
    EP3332474B1|2020-08-19|Virtual capacitance
    EP2602897B1|2014-09-17|Reactive power compensator and method for reducing the associated flickering phenomenon
    EP2859651B1|2017-12-27|Absorption circuit for absorbing a power ripple and associated method
    EP2756577A1|2014-07-23|Stabilization of a dc electric network
    EP2917992A1|2015-09-16|Method for controlling a multi-terminal vsc-hvdc network
    WO2010046331A1|2010-04-29|System and method for controlling at least one voltage converter with several cells in series
    WO2019008275A1|2019-01-10|Converter provided with a module for managing partly alternating power
    CA2685165A1|2008-11-06|System and method for control of a tcsc in an electricity transport network, specifically using a lyapunov approach
    EP2579442B1|2017-08-30|System for converting direct current into alternating current comprising a means for correcting the voltage supplied comprising means for measuring a low-frequency component of said voltage, and method for controlling such a system
    FR3053854A1|2018-01-12|MODULE FOR CONTROLLING THE INTERNAL ENERGY OF A CONVERTER
    EP3175528A1|2017-06-07|Method and device for charging a battery of a motor vehicle depending on the impedance of a power supply network and motor vehicle provided with such a charging device
    EP2582002A2|2013-04-17|Method for controlling the voltage in a grid comprising decentralised sources
    EP3520210B1|2020-08-05|Method for controlling a three-phase rectifier for a charging device on board an electrical or hybrid vehicle
    EP2158657B1|2010-09-01|Control system and method for a tcsc in an electric energy transport network in particular using a sliding-modes approach
    EP3047562A1|2016-07-27|Device for charging an automotive vehicle battery making it possible to compensate for the harmonics, automotive vehicle furnished with such a charging device and corresponding method of charging
    WO2018024977A1|2018-02-08|Method for controlling a multi-level modular converter
    FR3077441A1|2019-08-02|METHOD FOR CONTROLLING A THREE PHASE RECTIFIER FOR A THREE - PHASE INPUT CHARGING DEVICE.
    WO2022031157A1|2022-02-10|Method for controlling voltage source inverters to provide flexibility to ac electrical microgrids
    WO2020007884A1|2020-01-09|Device for active electrical compensation
    EP3807984A1|2021-04-21|Method for controlling a vienna rectifier
    FR3072516A1|2019-04-19|DEVICE FOR CHARGING AN ELECTRICAL ACCUMULATION BATTERY
    同族专利:
    公开号 | 公开日
    US20180226898A1|2018-08-09|
    US10312824B2|2019-06-04|
    JP6791964B2|2020-11-25|
    RU2709027C2|2019-12-13|
    FR3039940B1|2017-08-11|
    EP3332474B1|2020-08-19|
    DK3332474T3|2020-11-23|
    WO2017021642A1|2017-02-09|
    KR20180044306A|2018-05-02|
    JP2018522527A|2018-08-09|
    PL3332474T3|2021-04-06|
    CN107925362A|2018-04-17|
    CA2994372A1|2017-02-09|
    RU2018107570A|2019-09-05|
    CN107925362B|2021-01-12|
    EP3332474A1|2018-06-13|
    RU2018107570A3|2019-10-23|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US7292460B2|2003-10-17|2007-11-06|Abb Research Ltd.|Converter circuit for switching a large number of switching voltage levels|
    FR2937477B1|2008-10-21|2011-02-25|Areva T & D Sa|SYSTEM AND METHOD FOR CONTROLLING AT LEAST ONE MULTI-CELL VOLTAGE CONVERTER IN SERIES|
    AU2010291222B2|2009-09-04|2015-07-09|Hitachi Energy Switzerland Ag|A method and apparatus for calculating insertion indeces for a modular multilevel converter|
    EP2502340A1|2009-11-19|2012-09-26|Siemens Aktiengesellschaft|Converter and submodule of a converter for charging or discharging an energy store|
    BR112012014835A2|2009-12-17|2016-08-16|Abb Schweiz Ag|process for operating a direct converter circuit as well as device for performing the process|
    EP2348627A1|2010-01-25|2011-07-27|ABB Research Ltd.|Converter circuit and method for operating a multilevel converter circuit|
    EP2559143B1|2010-04-15|2014-01-01|ABB Research LTD|Modular multi-level power converter with second and third order harmonics reduction filter|
    EP2678932A2|2011-04-15|2014-01-01|Siemens Aktiengesellschaft|Multilevel converter and method of starting up a multilevel converter|
    CN103532418A|2013-04-18|2014-01-22|中国矿业大学|SVG submodule capacitor pre-charging strategy based on MMC|FR3065590B1|2017-04-20|2019-07-05|Supergrid Institute|DEVICE FOR CONTROLLING A TERMINAL FOR REINSTALLING POWER IN AN INSTALLATION|
    WO2019091543A1|2017-11-07|2019-05-16|Siemens Aktiengesellschaft|Method for operating a multi-phase multi-stage power converter and a corresponding multi-phase multi-stage power converter|
    CN108322049B|2018-02-12|2020-09-25|西安理工大学|Virtual capacitance control method for bidirectional direct current converter|
    EP3654517B1|2018-11-19|2021-06-02|Maschinenfabrik Reinhausen GmbH|Operating a modular multilevel converter|
    法律状态:
    2016-08-01| PLFP| Fee payment|Year of fee payment: 2 |
    2017-02-10| PLSC| Publication of the preliminary search report|Effective date: 20170210 |
    2017-08-21| PLFP| Fee payment|Year of fee payment: 3 |
    2018-07-23| PLFP| Fee payment|Year of fee payment: 4 |
    2020-05-19| PLFP| Fee payment|Year of fee payment: 6 |
    2021-05-17| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1557501A|FR3039940B1|2015-08-03|2015-08-03|VIRTUAL CAPACITY|FR1557501A| FR3039940B1|2015-08-03|2015-08-03|VIRTUAL CAPACITY|
    DK16758232.9T| DK3332474T3|2015-08-03|2016-07-29|VIRTUAL CAPACITY|
    US15/749,829| US10312824B2|2015-08-03|2016-07-29|Modular multilevel converter, method and control module for controlling the same|
    KR1020187006350A| KR20180044306A|2015-08-03|2016-07-29|Virtual capacitance|
    JP2018525817A| JP6791964B2|2015-08-03|2016-07-29|Virtual capacitance|
    PL16758232T| PL3332474T3|2015-08-03|2016-07-29|Virtual capacitance|
    CA2994372A| CA2994372A1|2015-08-03|2016-07-29|Capacite virtuelle|
    EP16758232.9A| EP3332474B1|2015-08-03|2016-07-29|Virtual capacitance|
    PCT/FR2016/051993| WO2017021642A1|2015-08-03|2016-07-29|Virtual capacitance|
    CN201680046016.3A| CN107925362B|2015-08-03|2016-07-29|Virtual capacitor|
    RU2018107570A| RU2709027C2|2015-08-03|2016-07-29|Virtual capacitance|
    [返回顶部]