AC motor drive system with a two phase power supply

Claim 2

An AC motor drive system for driving an AC motor having a first winding and a second winding, the first winding having first and second ends and a first winding impedance, the second winding having first and second ends and a second winding impedance that is greater than the first impedance, the drive system comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; the common terminal for connection to the respective first ends of the first and second windings; and the first phase terminal and the second phase terminal for connection to the second ends of the first and second windings, respectively; the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal, the first and second sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency and having a predetermined phase angle difference therebetween, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the second sinusoidal waveform signal, means, coupled to the waveform signal generating means to receive the first and second sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 3

The AC motor drive system of claim 1, wherein the power switching means includes a plurality of semiconductor switches driven to provide the two-phase output voltage, each semiconductor switch including overcurrent sensing means, connected to the voltage control means, for disabling the voltage control means upon sensing an overcurrent condition in the semiconductor switch.

Claim 4

The AC motor drive system of claim 1, wherein said means for providing sinusoidally weighted pulse width modulated switching signals includes: means for generating a fixed frequency comparison signal, the fixed frequency comparison signal having a frequency of approximately 7.5 KHz; and means for comparing the first and second sinusoidal waveform signals and the fixed frequency comparison signal to provide the sinusoidally weighted pulse width modulated switching signals.

Claim 5

The AC motor drive system of claim 1, wherein the waveform signal generating means further comprises: means, coupled to the oscillator means, for generating successive memory address signals; memory means, coupled to the address signal generating means, for providing a digital data signal in response to each address signal; and converting means for converting the digital data signals from the memory means into the first and second sinusoidal waveform signals.

Claim 6

The AC motor drive system of claim 4, wherein the direction control means comprises a logic inverting circuit for selectively inverting a signal from the address signal generating means and for supplying the selectively inverted signal to the converting means to drive the motor in a desired direction.

Claim 7

The AC motor drive system of claim 1, wherein the direction control means comprises a signal switching circuit for selectively swapping the first and second sinusoidal waveform to drive the motor in a desired direction.

Claim 8

An AC motor drive system for driving an AC motor having a first winding and a second winding, the first winding having first and second ends and a first winding impedance, the second winding having first and second ends and a second winding impedance that is greater than the first impedance, the drive system comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; the common terminal for connection to the respective first ends of the first and second windings; and the first phase terminal and the second phase terminal for connection to the second ends of the first and second windings, respectively; the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first, a second, and a third sinusoidal waveform signal, the first, second, and third sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency, the first and second sinusoidal waveform signals having a predetermined phase angle difference therebetween, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the third sinusoidal waveform signal, and means, coupled to the waveform signal generating means to receive the first, second, and third sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 9

An AC motor drive system for driving an AC motor having a first winding and a second winding, the first winding having first and second ends and a first winding impedance, the second winding having first and second ends and a second winding impedance that is greater than the first impedance, the drive system comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; the common terminal for connection to the respective first ends of the first and second windings; and the first phase terminal and the second phase terminal for connection to the second ends of the first and second windings, respectively; the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first, a second, and a third sinusoidal waveform signal, the first, second, and third sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency, the first and second sinusoidal waveform signals having a predetermined phase angle difference therebetween, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the third sinusoidal waveform signal, and means, coupled to the waveform signal generating means to receive the first, second, and third sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 10

The AC motor drive system of claim 7, wherein the power switching means includes a plurality of semiconductor switches driven to provide the two-phase output voltage, each semiconductor switch including overcurrent sensing means, connected to the voltage control means, for disabling the voltage control means upon sensing an overcurrent condition in the semiconductor switch.

Claim 11

The AC motor drive system of claim 7, wherein said means for providing sinusoidally weighted pulse width modulated switching signals includes: means for generating a fixed frequency comparison signal, the fixed frequency comparison signal having a frequency of approximately 7.5 KHz; and means for comparing the first, second, and third sinusoidal waveform signals and the fixed frequency comparison signal to provide the sinusoidally weighted pulse width modulated switching signals.

Claim 12

The AC motor drive system of claim 7, wherein the waveform signal generating means further comprises: means, coupled to the oscillator means, for generating a successive memory address signals and for generating a DAC select signal; memory means, coupled to the address signal generating means, for providing a digital data signal in response to each address signal; and converting means for converting the digital data signals from the memory means into the first, second, and third sinusoidal waveform signals.

Claim 13

The AC motor drive system of claim 10, wherein the direction control means comprises a logic inversion circuit for selectively inverting the DAC select signal from the address signal generating means and for supplying the selectively inverted DAC select signal to the converting mean to drive the motor in a desired direction.

Claim 14

The AC motor drive system of claim 7, wherein the direction control means comprises a switching circuit for selectively swapping the first and third sinusoidal waveform to drive the motor in a desired direction.

Claim 15

An AC motor drive system, for connection to a single-phase power supply having a line conductor and a neutral conductor, for driving an AC motor having a first winding and a second winding, the first winding having first and second ends and a first winding impedance, the second winding having first and second ends and a second winding impedance that is greater than the first impedance, the drive system comprising: two-phase power supply means, including a line terminal for coupling to the line conductor of the single-phase power supply, for converting the single-phase power supply into a two-phase output voltage, the two-phase power supply means having a first phase output terminal and a second phase output terminal; a neutral terminal for connection to the neutral conductor of the single-phase power source and for connection to the respective first ends of the first and second windings; and the first and second phase terminals for connection to the second ends of the first and second windings, respectively, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including waveform signal generating means for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal to have a predetermined phase angle difference therebetween and a common frequency that corresponds to a desired operating speed of the motor, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the second sinusoidal waveform signal, first means, coupled to the waveform signal generating means, for providing a first sinusoidally weighted pulse width modulated (PWM) switching signal, second means, coupled to the waveform signal generating means, for providing a second sinusoidally weighted pulse width modulated (PWM) switching signal, the first and second PWM signals operating as switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts power received from the single-phase power supply to a two-phase voltage to selectively drive the motor in either direction.

Claim 16

An AC motor drive system, for connection to a single-phase power supply having a line conductor and a neutral conductor, for driving an AC motor having a first winding and a second winding, the first winding having first and second ends and a first winding impedance, the second winding having first and second ends and a second winding impedance that is greater than the first impedance, the drive system comprising: two-phase power supply means, including a line terminal for coupling to the line conductor of the single-phase power supply, for converting the single-phase power supply into a two-phase output voltage, the two-phase power supply means having a first phase output terminal and a second phase output terminal; a neutral terminal for connection to the neutral conductor of the single-phase power source and for connection to the respective first ends of the first and second windings; and the first and second phase terminals for connection to the second ends of the first and second windings, respectively, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including waveform signal generating means for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal to have a predetermined phase angle difference therebetween and a common frequency that corresponds to a desired operating speed of the motor, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the second sinusoidal waveform signal, first means, coupled to the waveform signal generating means, for providing a first sinusoidally weighted pulse width modulated (PWM) switching signal, second means, coupled to the waveform signal generating means, for providing a second sinusoidally weighted pulse width modulated (PWM) switching signal, the first and second PWM signals operating as switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts power received from the single-phase power supply to a two-phase voltage to selectively drive the motor in either direction.

Claim 17

The AC motor drive system of claim 13, wherein the power switching means includes a plurality of semiconductor switches driven to provide the two-phase output voltage, each semiconductor switch including overcurrent sensing means, connected to the voltage control means, for disabling the voltage control means upon sensing an overcurrent condition in the semiconductor switch.

Claim 18

The AC motor drive system of claim 13, wherein said means for providing sinusoidally weighted pulse width modulated switching signals includes: means for generating a fixed frequency comparison signal, the fixed frequency comparison signal having a frequency of approximately 7.5 KHz; and means for comparing the first and second sinusoidal waveform signals and the fixed frequency comparison signal to provide the sinusoidally weighted pulse width modulated switching signals.

Claim 19

The AC motor drive system of claim 13, wherein the direction control means comprises a signal switching circuit for selectively swapping the first and second sinusoidal waveform to drive the motor in a desired direction.

Claim 20

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal, the first and second sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency and having a predetermined phase angle therebetween, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the second sinusoidal waveform signal, means, coupled to the waveform signal generating means to receive the first and second sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 21

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal, the first and second sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency and having a predetermined phase angle therebetween, the waveform signal generating means including direction control means, responsive to a direction control signal, for selectively changing the predetermined phase angle difference between the first sinusoidal waveform signal and the second sinusoidal waveform signal, means, coupled to the waveform signal generating means to receive the first and second sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 22

The AC motor drive system of claim 17, wherein the waveform signal generating means further comprises: means, coupled to the oscillator means, for generating successive memory address signals; memory means, coupled to the address signal generating means, for providing a digital data signal in response to each address signal; and converting means for converting the digital data signals from the memory means into the first and second sinusoidal waveform signals.

Claim 23

The AC motor drive system of claim 18, wherein the direction control means comprises a logic inverting circuit for selectively inverting a signal from the address signal generating means and for supplying the selectively inverted signal to the converting means to drive the motor in a desired direction.

Claim 24

The AC motor drive system of claim 17, wherein the direction control means comprises a signal switching circuit for selectively swapping the first and second sinusoidal waveform to drive the motor in a desired direction.

Claim 25

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first, a second, and a third sinusoidal waveform signal, the first, second, and third sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency, the waveform signal generating means including direction control means, responsive to a direction control signal, for reversing the direction of the AC motor by changing the predetermined phase angle difference between the first sinusoidal waveform signal and the third sinusoidal waveform signal, means, coupled to the waveform signal generating means to receive the first, second, and third sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selective drive the motor in either direction.

Claim 26

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply voltage to the two-phase output voltage, and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including oscillator means for generating an oscillating signal having a frequency representative of a desired operating speed of the motor, waveform signal generating means, responsive to the oscillating signal, for generating a first, a second, and a third sinusoidal waveform signal, the first, second, and third sinusoidal waveform signals each having a frequency determined by the oscillating signal frequency, the waveform signal generating means including direction control means, responsive to a direction control signal, for reversing the direction of the AC motor by changing the predetermined phase angle difference between the first sinusoidal waveform signal and the third sinusoidal waveform signal, means, coupled to the waveform signal generating means to receive the first, second, and third sinusoidal waveform signals, for providing sinusoidally weighted pulse width modulated (PWM) switching signals as the switching control signals to control the operation of the power switching means, whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selective drive the motor in either direction.

Claim 27

The AC motor drive system of claim 21, wherein the waveform signal generating means further comprises: means, coupled to the oscillator means, for generating a successive memory address signals and for generating a DAC select signal; memory means, coupled to the address signal generating means, for providing a digital data signal in response to each address signal; and converting means for converting the digital data signals from the memory means into the first, second, and third sinusoidal waveform signals.

Claim 28

The AC motor drive system of claim 22, wherein the direction control means comprises a logic inversion circuit for selectively inverting the DAC select signal from the address signal generating means and for supplying the selectively inverted DAC select signal to the converting means to drive the motor in a desired direction.

Claim 29

The AC motor drive system of claim 21, wherein the direction control means comprises a switching circuit for selectively swapping the first and third sinusoidal waveform to drive the motor in a desired direction.

Claim 30

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply to the two-phase output voltage; and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including waveform signal generating means for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal to have a predetermined phase angle difference therebetween and a common frequency that corresponds to a desired operating speed of the motor, the waveform signal generating means including direction control means, responsive to a direction control signal, for reversing the direction of the AC motor by changing the predetermined phase angle difference between the first sinusoidal waveform signal and a second sinusoidal waveform signal, first means, coupled to the waveform signal generating means, for providing a first sinusoidally weighted pulse width modulated (PWM) switching signal, second means, coupled to receive the second sinusoidal waveform signal and the fixed frequency signal, for providing a second sinusoidally weighted pulse width modulated (PWM) switching signal, the first and second PWM signals operating as switching control signals to control the operation of the power switching means, and whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 31

An AC motor drive system, comprising: two-phase power supply means for converting an inputted power supply voltage into a two-phase AC output voltage, the two-phase power supply means having a common terminal, a first phase output terminal, and a second phase output terminal; an AC motor having a first winding and a second winding; the first winding having first and second ends and a first winding impedance; the second winding having first and second ends and a second winding impedance that is greater than the first impedance; the respective first ends of the first and second windings being connected to the common terminal of the two-phase power supply means; and the second ends of the first and second windings being respectively connected to the first phase terminal and the second phase terminal of the two-phase power supply means, the two-phase power supply means including power switching means for selectively converting the inputted power supply to the two-phase output voltage; and voltage control means for generating switching control signals for controlling the operation of the power switching means; the voltage control means including waveform signal generating means for generating a first sinusoidal waveform signal and a second sinusoidal waveform signal to have a predetermined phase angle difference therebetween and a common frequency that corresponds to a desired operating speed of the motor, the waveform signal generating means including direction control means, responsive to a direction control signal, for reversing the direction of the AC motor by changing the predetermined phase angle difference between the first sinusoidal waveform signal and a second sinusoidal waveform signal, first means, coupled to the waveform signal generating means, for providing a first sinusoidally weighted pulse width modulated (PWM) switching signal, second means, coupled to receive the second sinusoidal waveform signal and the fixed frequency signal, for providing a second sinusoidally weighted pulse width modulated (PWM) switching signal, the first and second PWM signals operating as switching control signals to control the operation of the power switching means, and whereby the two-phase power supply means converts the inputted power supply voltage to a two-phase voltage provided on the first, second, and common terminals to selectively drive the motor in either direction.

Claim 32

The AC motor drive system of claim 25, wherein the direction control means comprises a signal switching circuit for selectively swapping the first and second sinusoidal waveform to drive the motor in a desired direction.