US 7,402,969 B2Granted

Method for producing voltage waveforms in a PWM motor controller of a PM DC brushless motor

AssigneeDelphi Technologies, Inc.

InventorsRobert J. Disser, Monty L. Crabill

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Abstract

A method produces PWM voltage waveforms in a PWM motor controller of a three phase PM DC brushless motor, wherein the motor controller has first, second and third half H-bridge transistor pairs to generate the voltage waveforms to electronically commutate the motor. The first transistor pair is always assigned to the first phase for every commutation state requiring a voltage waveform from the first transistor pair. The second and third transistor pair are similarly assigned. The first method also includes always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period when a commutation state requires a voltage waveform from the first transistor pair but delaying starting a voltage waveform generated by the second transistor pair by substantially ⅓ of the PWM period and delaying starting a voltage waveform generated by the third transistor pair by substantially ⅔ of the PWM period.

Claims22

Dependent claims

A method for producing PWM voltage waveforms in a PWM motor controller of a PM DC brushless motor, wherein the motor has commutation states and first, second and third phases, wherein the voltage waveforms have a PWM period for each commutation state, wherein the motor controller has first, second and third half H-bridge transistor pairs to generate the voltage waveforms to electronically commutate the motor, and wherein the method comprises:

a) always assigning the first transistor pair to the first phase for every commutation state requiring a voltage waveform from the first transistor pair;
b) always assigning the second transistor pair to the second phase for every commutation state requiring a voltage waveform from the second transistor pair;
c) always assigning the third transistor pair to the third phase for every commutation state requiring a voltage waveform from the third transistor pair;
d) always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period for a commutation state when the commutation state requires a voltage waveform from the first transistor pair;
e) always delaying starting a voltage waveform generated by the second transistor pair by substantially ⅓ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the second transistor pair;
and
f) always delaying starting a voltage waveform generated by the third transistor pair by substantially ⅔ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the third transistor pair.

4 more elements

a) always assigning the first transistor pair to the first phase for every commutation state requiring a voltage waveform from the first transistor pair;
b) always assigning the second transistor pair to the second phase for every commutation state requiring a voltage waveform from the second transistor pair;
c) always assigning the third transistor pair to the third phase for every commutation state requiring a voltage waveform from the third transistor pair;
d) always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period for a commutation state when the commutation state requires a voltage waveform from the first transistor pair;
e) always delaying starting a voltage waveform generated by the second transistor pair by substantially ⅓ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the second transistor pair;
f) always delaying starting a voltage waveform generated by the third transistor pair by substantially ⅔ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the third transistor pair;
and
g) operating the motor in all four quadrants of a motor torque versus motor speed diagram.

5 more elements

a) always assigning the first transistor pair to the first phase for every commutation state requiring a voltage waveform from the first transistor pair;
b) always assigning the second transistor pair to the second phase for every commutation state requiring a voltage waveform from the second transistor pair;
c) always assigning the third transistor pair to the third phase for every commutation state requiring a voltage waveform from the third transistor pair;
d) always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period for a commutation state when the commutation state requires a voltage waveform from the first transistor pair;
e) always delaying starting a voltage waveform generated by the second transistor pair by substantially ⅓ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the second transistor pair;
f) always delaying starting a voltage waveform generated by the third transistor pair by substantially ⅔ of the PWM period for the commutation state when the commutation state requires a voltage waveform from the third transistor pair;
and
g) operating the motor in all four quadrants of a motor torque versus motor speed diagram,
wherein each commutation state requires voltage waveforms from exactly two of the first, second and third transistor pairs,
wherein each voltage waveform has a duty cycle which can be adjusted from a first duty cycle equal to a predetermined minimum duty cycle required for the motor controller to sample current in the motor and a second duty cycle equal to the predetermined minimum duty cycle plus a desired duty cycle, and wherein the desired duty cycle is less than the predetermined minimum duty cycle, and
wherein for each commutation state the voltage waveform of one of the two transistor pairs has a duty cycle equal to the second duty cycle and the other of the two transistor pairs has a duty cycle equal to the first duty cycle.

8 more elements

Dependencies are inferred from the claim text.