Speed based gain correction for three level inverter midpoint control
AssigneeHamilton Sundstrand Corporation
InventorsJordan K. Vanevenhoven, Curtis J. Plude, Gary L. Miles
Life of this patent
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Abstract
A system and method for controlling a DC midpoint terminal voltage of a three level inverter is provided. The method includes receiving an input power signal at a three level motor control system that includes a three level inverter, the three level inverter powering an electric motor, determining, in the three level motor control system, a speed value of the electric motor, and adjusting a zero-sequence inverter output voltage to adjust a midpoint voltage at the DC midpoint based on the determined speed value.
Claims18
A method of balancing a DC midpoint of a three level inverter, the method comprising:
- receiving an input power signal at a three level motor control system that includes a three level inverter, the three level inverter powering an electric motor;
- determining, in the three level motor control system, a speed value of the electric motor;
- and
- adjusting a zero-sequence inverter output voltage to adjust a midpoint voltage at the DC midpoint based on the determined speed value, wherein adjusting the zero-sequence inverter output voltage from the three level inverter to adjust the midpoint voltage based on the determined speed value further comprises:
- setting a desired midpoint unbalanced value to zero volts;
- calculating a first temporary value by subtracting a DC midpoint unbalanced value from the desired midpoint unbalanced value, wherein the DC midpoint unbalanced value is equal to a first voltage value for a capacitor VUP minus a second voltage value for a capacitor VDN, divided by two;
- scaling the determined speed value;
- generating a second temporary value by multiplying the first temporary value by the scaled determined speed value;
- generating, using a regulator transfer function (C(s)), a commanded zero sequence inverter output voltage (VO*) based on the second temporary value;
- and
- applying the commanded zero sequence inverter output voltage to the three level inverter with open loop gain G(s), resulting in alteration of the DC midpoint voltage.
A three level motor controller system for balancing a DC midpoint of a three level inverter, the three level motor controller system comprising:
- a controller configured to:
- receive an input power signal at the three level motor control system that includes a three level inventor, the three level inverter powering an electric motor;
- determine a speed value of the electric motor;
- adjust a zero-sequence inverter output voltage to adjust a midpoint voltage at the DC midpoint based on the determined speed value, wherein adjusting the zero-sequence inverter output voltage from the three level inverter to adjust the midpoint voltage based on the determined speed value further comprises:
- setting a desired midpoint unbalanced value to zero volts;
- calculating a first temporary value by subtracting a DC midpoint unbalanced value from the desired midpoint unbalanced value, wherein the DC midpoint unbalanced value is equal to a first voltage value for capacitor VUP minus a second voltage value for capacitor VDN, divided by two;
- scaling the determined speed value;
- generating a second temporary value by multiplying the first temporary value by the scaled determined speed value;
- generating, using a regulator transfer function (C(s)), a commanded zero sequence inverter output voltage (VO*) based on the second temporary value;
- and
- applying the commanded zero sequence inverter output voltage to the three level inverter with open loop gain G(s), resulting in alteration of the DC midpoint voltage.
A computer program product for balancing a DC midpoint of a three level inverter in a three level motor controller system, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor and the system to cause the system and processor to:
- instruct, using the processor, a power source to provide an input power signal to the three level motor controller system;
- receive the input power signal at the three-level motor controller system that includes a three level inverter, the three level inverter powering an electric motor;
- determining, in the three level motor control system, a speed value of the electric motor;
- adjust a zero-sequence inverter output voltage from the three level inverter to adjust a midpoint voltage at the DC midpoint based on the determined speed, wherein adjusting the zero-sequence inverter output voltage from the three level inverter to adjust the midpoint voltage based on the determined speed value further comprises:
- setting a desired midpoint unbalanced value to zero volts;
- calculating a first temporary value by subtracting a DC midpoint unbalanced value from the desired midpoint unbalanced value, wherein the DC midpoint unbalanced value is equal to a first voltage value for capacitor VUP minus a second voltage value for capacitor VDN, divided by two;
- scaling the determined speed value;
- generating a second temporary value by multiplying the first temporary value by the scaled determined speed value;
- generating, using a regulator transfer function (C(s)), a commanded zero sequence inverter output voltage (VO*) based on the second temporary value;
- and
- applying the commanded zero sequence inverter output voltage to the three level inverter with open loop gain G(s), resulting in alteration of the DC midpoint voltage.
Dependencies are inferred from the claim text.