Method and apparatus for phase current balance in active converter with unbalanced AC line voltage source
AssigneeRockwell Automation Technologies, Inc.
InventorsSemyon Royak, Robert J. Breitzmann, Mark M. Harbaugh
Life of this patent
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Abstract
Active power converters and methods are presented for converting input electrical power to output electrical power with converter switching control in which the individual phase voltage command values are compensated according to phase line voltage imbalances to compensate the converter control to provide balanced phase currents in the presence of unbalanced phase supply line voltages.
Claims20
A method for controlling an active power converter providing a regulated DC output by switching current from a multiphase voltage source to balance phase currents in the presence of unbalanced phase supply line voltages, the method comprising:
- measuring phase supply line voltage values of the input;
- determining d and q axis voltage command values in a synchronous reference frame based at least partially on the measured phase supply line voltages;
- converting the synchronous reference frame voltage command values to stationary phase voltage reference command values for each phase;
- determining DC voltage trim values for each phase at least partially according to the measured phase supply line voltages;
- determining a phase command signal based at least partially on the phase voltage reference command value and the DC voltage trim value for each phase;
- and
- controlling the active power converter at least partially according to the phase command signals.
An active power conversion system for converting input electrical power to output electrical power, comprising:
- an input for receiving input electrical power from a multiphase AC voltage source;
- an output providing DC electrical power;
- a switch array converter comprising a plurality of switching devices operatively coupled between the input and the output and operative according to a plurality of switching control signals to selectively couple the input to the output;
- and
- a control system operatively coupled with the converter to provide the switching control signals to convert AC input power to output DC power, the control system comprising a current balancing component operative to control the converter to balance phase currents in the presence of unbalanced phase supply line voltages by determining DC voltage trim values for each phase at least partially according to the measured phase supply line voltages and operating the switching devices according to a phase command signal based at least partially on a phase voltage reference command value and the DC voltage trim value for each phase.
A computer readable medium with computer-executable instructions for controlling an active power converter providing a regulated DC output by switching current from a multiphase voltage source to balance phase currents in the presence of unbalanced phase supply line voltages, the computer readable medium comprising computer-executable instructions for:
- measuring phase supply line voltage values of the input;
- determining d and q axis voltage command values in a synchronous reference frame based at least partially on the measured phase supply line voltages;
- converting the synchronous reference frame voltage command values to stationary phase voltage reference command values for each phase;
- determining DC voltage trim values for each phase at least partially according to the measured phase supply line voltages;
- determining a phase command signal based at least partially on the phase voltage reference command value and the DC voltage trim value for each phase;
- and
- controlling the active power converter at least partially according to the phase command signals.
Dependencies are inferred from the claim text.