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US 11,456,680 B2Granted
Over-modulation pulse width modulation with maximum output and minimum harmonics
AssigneeHamilton Sundstrand Corporation
InventorsHuazhen Chai, Mustansir Kheraluwala
Life of this patent
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Abstract
A power system includes an inverter that convert a DC voltage to a three-phase alternating current (AC) voltage. One or more switch drivers generate a pulse width modulation (PWM) drive signal that drives the inverter. The power system further includes a controller that determines a modulation index associated with the PWM drive signal and injects a harmonic into the PWM drive signal in response to the modulation index exceeding a modulation index threshold value.
Claims4
A power system comprising:
- a power source configured to generate a direct current (DC) voltage;
- an inverter in signal communication with the power source, the inverter configured to convert the DC voltage to a three-phase alternating current (AC) voltage;
- at least one switch driver configured to generate a pulse width modulation (PWM) drive signal that drives the inverter, the PWM drive signal including a fundamental signal component in a form of a sine wave;
- and
- a controller in signal communication with the inverter, the controller configured to determine a modulation index associated with the PWM drive signal based on a power demand of a load connected to an output of the inverter and to inject a third harmonic of the sine wave into the PWM drive signal in response to the modulation index exceeding a modulation index threshold value that is set at a saturation voltage associated with the PWM drive signal and has a value of about 1.125,
- wherein the controller decreases an amplitude of the fundamental signal component while increasing an amplitude of the third harmonic so as to generate the PWM drive signal, and a total amplitude of the three-phase AC voltage is increased without saturating the fundamental signal component,
- wherein the controller determines an optimization region of the third harmonic from a first modulation index value to a second modulation index value, exponentially increases the amplitude of the third harmonic within the optimization region, and optimizes a plurality of voltage values residing in the optimization region of the third harmonic.
4 more elements
A method of supplying power to a load, the method comprising:
- generating a direct current (DC) voltage;
- converting, via an inverter, the DC voltage to a three-phase alternating current (AC) voltage;
- generating, via at least one switch driver, a pulse width modulation (PWM) drive signal that drives the inverter, the PWM drive signal including a fundamental signal component in a form of a sine wave;
- determining, via a controller, a modulation index associated with the PWM drive signal based on a power demand of the load which is connected to an output of the inverter;
- injecting a third harmonic of the sine wave into the PWM drive signal in response to the modulation index exceeding a modulation index threshold value that is set at a saturation voltage associated with the PWM drive signal and has a value of about 1.125;
- decreasing, via the controller, an amplitude of the fundamental signal component while increasing an amplitude of the third harmonic so as to generate the PWM drive signal, and increasing a total amplitude of the three-phase AC voltage without saturating the fundamental signal component in response to increasing the amplitude of the third harmonic;
- determining, via the controller, an optimization region of the third harmonic from a first modulation index value to a second modulation index value, and exponentially increasing the amplitude of the third harmonic within the optimization region;
- and
- optimizing, via the controller, a plurality of voltage values residing in the optimization region of the third harmonic.
6 more elements
Dependencies are inferred from the claim text.