Converter pulse width modulation strategies for three phase regenerative drives
First Claim
1. A three-phase regenerative drive employing multiple converter pulse width modulation (PWM) strategies, the drive comprising:
- a three-phase converter having inputs for connection to a three-phase AC source, the three-phase converter having three phase legs;
a DC bus operably connected to the three-phase converter wherein the three phase converter is configured to direct current from the three-phase AC source to the DC bus;
a three-phase inverter operably connected to the DC bus and a motor, the three phase inverter configured to draw current from the DC bus and provide three phase command signals to the motor; and
wherein the three-phase converter employs a first PWM strategy to supply current to the DC bus, and the three-phase converter employs a second PWM strategy to supply current to the DC bus if a total current in the three phase legs exceeds a selected current threshold.
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Abstract
A three-phase regenerative drive employing multiple converter pulse width modulation (PWM) strategies. The drive includes a three-phase converter having inputs for connection to a three-phase AC source, the three-phase converter having three phase legs, a DC bus operably connected to the three-phase converter wherein the three phase converter is configured to direct current from the three-phase AC source to the DC bus, and a three-phase inverter operably connected to the DC bus and a motor, the three phase inverter configured to draw current from the DC bus and provide three phase command signals to the motor. The three-phase converter employs a first PWM strategy to supply current to the DC bus, and the converter employs a second PWM strategy to supply current to the DC bus if a total current in the three phase legs exceeds a selected threshold.
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Citations
22 Claims
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1. A three-phase regenerative drive employing multiple converter pulse width modulation (PWM) strategies, the drive comprising:
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a three-phase converter having inputs for connection to a three-phase AC source, the three-phase converter having three phase legs; a DC bus operably connected to the three-phase converter wherein the three phase converter is configured to direct current from the three-phase AC source to the DC bus; a three-phase inverter operably connected to the DC bus and a motor, the three phase inverter configured to draw current from the DC bus and provide three phase command signals to the motor; and wherein the three-phase converter employs a first PWM strategy to supply current to the DC bus, and the three-phase converter employs a second PWM strategy to supply current to the DC bus if a total current in the three phase legs exceeds a selected current threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of operating a three phase regenerative drive to drive a motor from a three phase AC source, the drive comprising a three-phase converter having three phase legs, a three phase inverter, and a DC bus connected between the converter and the inverter, and a controller, the controller executing the method comprising:
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determining a total current in the three phase legs; controlling the three phase converter with a first pulse width modulation (PWM) technique to cause the three phase converter to supply power to the DC bus; if a total current in the three phase legs exceeds a selected threshold, controlling the three-phase converter to employs a second PWM strategy to supply current to the DC bus. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification