Feedforward control of motor drives with output sinewave filter
First Claim
1. A power conversion system, comprising:
- an inverter comprising a DC input, an AC output, and a plurality of switching devices coupled between the DC input and the AC output and operative according to inverter switching control signals to convert DC electrical power received at the DC input to provide AC electrical output power at the AC output to drive a motor load through an intervening output filter, a transformer and a cable; and
a controller, including;
a current regulator component implemented by a processor to compute a command value according to a current reference value and a motor current feedback value,a cross-coupled feedforward component implemented by the processor to compensate the command value by an estimated cross-coupled voltage value to compute a control output value, anda cross-coupled object component implemented by the processor to compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load;
the controller being operative to provide the inverter switching control signals to control the inverter according to the control output value;
wherein the current regulator component computes a d-axis command value according to a d-axis current reference value and a d-axis motor current feedback value, and computes a q-axis command value according to a q-axis current reference value and a q-axis motor current feedback value; and
wherein the cross-coupled feedforward component compensates the d-axis command value by subtracting an estimated q-axis voltage value from the d-axis command value to compute a d-axis control output value, and wherein the cross-coupled feedforward component compensates the q-axis command value by adding an estimated d-axis voltage value to the q-axis command value to compute a q-axis control output value.
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Accused Products
Abstract
Disclosed examples include power conversion systems and methods to operate an inverter to drive a motor load through an intervening output filter, a transformer and a cable, including a current regulator to compute a command value according to a current reference value and a motor current feedback value, a cross-coupled feedforward component to compensate the command value by an estimated cross-coupled voltage value to compute a control output value, a cross-coupled object component to compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load, and a controller to provide the inverter switching control signals to control the inverter according to the control output value.
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Citations
16 Claims
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1. A power conversion system, comprising:
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an inverter comprising a DC input, an AC output, and a plurality of switching devices coupled between the DC input and the AC output and operative according to inverter switching control signals to convert DC electrical power received at the DC input to provide AC electrical output power at the AC output to drive a motor load through an intervening output filter, a transformer and a cable; and a controller, including; a current regulator component implemented by a processor to compute a command value according to a current reference value and a motor current feedback value, a cross-coupled feedforward component implemented by the processor to compensate the command value by an estimated cross-coupled voltage value to compute a control output value, and a cross-coupled object component implemented by the processor to compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load; the controller being operative to provide the inverter switching control signals to control the inverter according to the control output value; wherein the current regulator component computes a d-axis command value according to a d-axis current reference value and a d-axis motor current feedback value, and computes a q-axis command value according to a q-axis current reference value and a q-axis motor current feedback value; and wherein the cross-coupled feedforward component compensates the d-axis command value by subtracting an estimated q-axis voltage value from the d-axis command value to compute a d-axis control output value, and wherein the cross-coupled feedforward component compensates the q-axis command value by adding an estimated d-axis voltage value to the q-axis command value to compute a q-axis control output value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of operating an inverter to drive a motor load through an output filter and a transformer, the method comprising:
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implementing a current regulator component to compute a command value according to a current reference value and a motor current feedback value; implementing a cross-coupled feedforward component to compensate the command value by an estimated cross-coupled voltage value to compute a control output value; implementing a cross-coupled object component to compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load; and providing inverter switching control signals to control the inverter according to the control output value; further comprising implementing the current regulator component to compute a d-axis command value according to a d-axis current reference value and a d-axis motor current feedback value, and to compute a q-axis command value according to a q-axis current reference value and a q-axis motor current feedback value; and further comprising implementing the cross-coupled feedforward component to compensate the d-axis command value by subtracting an estimate q-axis voltage value from the d-axis command value to compute a d-axis control output value, and implementing the cross-coupled feedforward component to compensate the q-axis command value by adding an estimated d-axis voltage value to the q-axis command value to compute a q-axis control output value. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A non-transitory computer readable medium including computer executable instructions which, when executed by a processor, cause the processor to:
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compute a command value according to a current reference value and a motor current feedback value; compensate the command value by an estimated cross-coupled voltage value to compute a control output value; compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load; and control the inverter according to the control output valuei, compute a d-axis command value according to a d-axis current reference value and a d-axis motor current feedback value, and compute a q-axis command value according to a q-axis current reference value and a q-axis motor current feedback value; and compensate the d-axis command value by subtracting an estimated q-axis voltage value from the d-axis command value to compute a d-axis control output value, and compensate the q-axis command value by adding an estimated d-axis voltage value to the q-axis command value to compute a q-axis control output value.
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Specification