Modular multilevel converter, method and control module for controlling the same
AssigneesSupergrid Institute, Institut National Des Sciences Appliquees De Lyon, Centralesupelec
InventorsKosei Shinoda, Abdelkrim Benchaib, Xavier Guillaud, Jing Dai
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Abstract
The invention relates to a modular multilevel converter (2) having a control module (4) and a computer (10) for computing a setpoint for the internal energy of the converter stored in the capacitors of the submodules of the arms. The control module is configured to deduce, from the setpoint for the internal energy of the converter, a setpoint for the voltage across the terminals of each modeled capacitor, which setpoint is used for regulating the voltage across the points of common coupling between the converter and the DC power supply network and the voltage across the terminals of each modeled capacitor.
Claims16
A multilevel modular voltage converter for converting AC voltage into DC voltage and DC voltage into AC voltage, the converter comprising:
- a DC portion configured to be connected to a DC power supply network;
- and
- an AC portion configured to be connected to an AC power supply network;
- a plurality of legs, each of said legs comprising an upper arm and a lower arm, each of said upper arms and lower arms comprising a plurality of submodules that are individually controllable by a control member specific to each of said submodules,
- wherein, in each of said upper arms and lower arms, each of said submodule comprises a capacitor that is connected in series in the respective arm when the control member of the submodule is in an ON state, each of said upper arms and lower arms being configured to model as a modeled voltage source associated with a duty ratio depending on a number of capacitors connected in series in the respective arm, each modeled voltage source being in parallel with a modeled capacitor corresponding to a total capacitance of the respective arm,
- wherein the converter further comprises a converter control module configured to regulate a voltage across terminals of each modeled capacitor of each leg and to regulate a voltage at connecting points between the converter and the DC power supply network by controlling said control members of the submodules of the converter,
- wherein the control module of the converter comprises a computer that computes a setpoint for an internal energy of the converter stored in the capacitors of the submodules of each of said upper arms and lower arms by applying a function having an adjustable input parameter, the control module being configured to deduce, from said setpoint for the internal energy, a setpoint for a voltage across the terminals of each modeled capacitor used for regulating the voltage at the connecting points between the converter and the DC power supply network and the voltage across the terminals of each modeled capacitor.
A method of controlling a multilevel modular voltage converter, the converter serving to convert AC voltage into DC voltage and DC voltage into AC voltage, said converter including a DC portion configured to be connected to a DC power supply network and an AC portion configured to be connected to an AC power supply network, the converter having a plurality of legs, each of said legs comprising an upper arm and a lower arm, each of said upper arms and lower arms having a plurality of submodules that are individually controllable by a control member specific to each of said submodules, and in each of said upper arms and lower arms, each of said submodules comprising a capacitor that is connected in series in the respective arm when the control member of the submodule is in an ON state, each of said upper arms and lower arms being configured to model as a modeled voltage source associated with a duty ratio depending on a number of capacitors connected in series in the respective arm, each modeled voltage source being in parallel with a modeled capacitor corresponding to a total capacitance of the respective arm, the method further comprising:
- controlling of the converter, in which a voltage across terminals of each modeled capacitor of each leg is regulated and a voltage at connecting points between the converter and the DC power supply network is regulated by controlling said control members of the submodules of the converter,
- calculating a setpoint for an internal energy of the converter stored in the capacitors of the submodules of each of said upper arms and lower arms by using a function having an adjustable input parameter, and
- calculating a setpoint for the voltage across the terminals of each modeled capacitor from said setpoint for the internal energy of the converter, the setpoint for the voltage across the terminals of each modeled capacitor being used for regulating the voltage at the connecting points between the converter and the DC power supply network and the voltage across the terminals of each modeled capacitor.
A control module for controlling a multilevel modular voltage converter, the converter being configured for converting AC voltage into DC voltage and DC voltage into AC voltage, the converter comprising a DC portion configured to be connected to a DC power supply network and an AC portion configured to be connected to an AC power supply network, the converter comprising a plurality of legs, each of said legs comprising an upper arm and a lower arm, each of said upper arms and lower arms comprising a plurality of submodules that are individually controllable by a control member specific to each of said submodules, and in each of said upper arms and lower arms, each of said submodules comprising a capacitor that is connected in series in the respective arm when the control member of the submodule is in an ON state, each of said upper arms and lower arms being configured to model as a modeled voltage source associated with a duty ratio depending on a number of capacitors connected in series in the respective arm, each modeled voltage source being in parallel with a modeled capacitor corresponding to a total capacitance of the respective arm, wherein
- said control module is included in said converter, and
- said control module is configured to regulate a voltage across terminals of each modeled capacitor of each leg and to regulate a voltage at connecting points between the converter and the DC power supply network by controlling said control members of the submodules of the converter,
- wherein said control module comprises a computer that computes a setpoint for an internal energy of the converter stored in the capacitors of the submodules of each of said upper arms and lower arms by applying a function having an adjustable input parameter, and wherein said control module is configured to deduce, from said setpoint for the internal energy, a setpoint for a voltage across the terminals of each modeled capacitor used for regulating the voltage at the connecting points between the converter and the DC power supply network and the voltage across the terminals of each modeled capacitor.
Dependencies are inferred from the claim text.