NEUTRAL POINT CLAMPED CONVERTER CONTROL SYSTEM AND CONTROL METHOD AND COMPENSATION UNIT
First Claim
1. A control system for providing commands to a multi-level converter for balancing a neutral point voltage of the multi-level converter, the control system comprising:
- a fundamental control unit configured to generate fundamental commands to implement fundamental power conversion operation for the multi-level converter;
a first compensation control unit configured to generate a first compensation signal for injection into the fundamental command to balance the neutral point voltage when the multi-level converter is in operation in a first state;
a second compensation control unit configured to generate a second compensation signal for injection into the fundamental command to balance the neutral point voltage when the multi-level converter is in operation in a second state, wherein the first state is different from the second state;
a switch control unit configured to detect the state of the multi-level converter and provide a first switch signal and a second switch signal respectively corresponding to the first state and the second state; and
a switch implementation unit configured to switch the fundamental control unit to communicate with the first compensation control unit according to the first switch signal and switch the fundamental control unit to communicate with the second compensation control unit according to the second switch signal.
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Accused Products
Abstract
A control system includes a fundamental control unit, first and second compensation control units, a switch control unit, and a switch implementation unit. The fundamental control unit generates fundamental commands to implement fundamental power conversion operation for a converter. The first compensation control unit generates a first compensation signal for injection into the fundamental command to balance neutral point voltage when the converter is in operation in a first state. The second compensation control unit generates a second compensation signal for injection into the fundamental command to balance neutral point voltage when the converter is in operation in a second state. The switch control unit detects first and second states of the converter and provides first and second switch signals respectively. The switch implementation unit switches the fundamental control unit to communicate with the first and second compensation control units according to the first and second switch signals respectively.
20 Citations
20 Claims
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1. A control system for providing commands to a multi-level converter for balancing a neutral point voltage of the multi-level converter, the control system comprising:
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a fundamental control unit configured to generate fundamental commands to implement fundamental power conversion operation for the multi-level converter; a first compensation control unit configured to generate a first compensation signal for injection into the fundamental command to balance the neutral point voltage when the multi-level converter is in operation in a first state; a second compensation control unit configured to generate a second compensation signal for injection into the fundamental command to balance the neutral point voltage when the multi-level converter is in operation in a second state, wherein the first state is different from the second state; a switch control unit configured to detect the state of the multi-level converter and provide a first switch signal and a second switch signal respectively corresponding to the first state and the second state; and a switch implementation unit configured to switch the fundamental control unit to communicate with the first compensation control unit according to the first switch signal and switch the fundamental control unit to communicate with the second compensation control unit according to the second switch signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A control method for balancing neutral point voltage of a multi-level converter, the control method comprising:
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obtaining a reference parameter related to the state of the multi-lever converter; determining the state of the multi-lever converter according to the reference parameter; generating a fundamental command from a fundamental control unit to implement fundamental power conversion of the multi-level converter; when the state of the multi-level converter is in a first state, switching the fundamental control unit to communicate with a first compensation control unit, generating a first compensation signal with the first compensation control unit, and injecting the first compensation signal into the fundamental command to balance the neutral point voltage of the multi-level converter; and when the state of the multi-level converter is in a second state, switching the fundamental control unit to communicate with a second compensation control unit, generating a second compensation signal with the second compensation control unit, and injecting the second compensation signal into the fundamental command to balance the neutral point voltage of the multi-level converter, wherein the first state is different from the second state. - View Dependent Claims (14, 15, 16)
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17. A compensation control unit for providing a compensation command for balancing neutral point voltage of a multi-level converter, the compensation control unit comprising:
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a difference element configured to obtain a voltage error signal representative of neutral point voltage imbalance; a neutral point voltage regulator configured to receive the voltage error signal and produce a fundamental compensation command for driving the voltage error signal towards zero; and an odd harmonics signal generator configured to transform the fundamental compensation command to odd harmonics signals in the dq coordinates. - View Dependent Claims (18, 19, 20)
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Specification