Motor control apparatus
AssigneeSeikon Epson Corporation
InventorsShigeo Kanna, Akihito Uetake
Life of this patent
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Abstract
A motor control apparatus is provided which is capable of preventing large, accidental switching surges and suppressing switching surges that hamper efforts to improve the efficiency of PWM control inverters. The motor control apparatus has a PWM control inverter and axial position detector 3 that detects the position of the rotary axis of motor 14. Gate drive circuit 1 of the PWM control inverter comprises decoder circuit 4, correction gate circuit 5, and logical AND circuit 6. The correction gate circuit 5 sets a time difference at the change point for PWM signals and at the change point for commutation signals.
Claims35
A motor control apparatus that controls the operation of a motor by means of a pulse wave modulated control inverter having a PWM signal changing from one state to another state at a first change point and a commutation signal changing from one state to another state at a second change point, wherein the commutation signal is based on an axial position of the motor, comprising:
- correction means for setting, during motor operation, a time difference of the PWM signal at the first change point and the commutation signal at the second change point.
A method of controlling the operation of a motor by means of a pulse wave modulated control inverter having a PWM signal changing from one state to another state at a first change point and a commutation signal changing from one state to another state at a second change point, wherein the commutation signal is based on an axial position of the motor, comprising the step of:
- setting, during motor operation, a time difference of the PWM signal at the first change point and the commutation signal at the second change point.
A motor control apparatus for controlling a motor, comprising:
- a commutation circuit for outputting a commutation signal based on an axial position of the motor, wherein the commutation signal comprises first and second states, wherein the commutation signal changes from the first state to the second state at a first change point;
- a PWM circuit for generating a PWM signal, wherein the PWM signal comprises first and second states, wherein the PWM signal changes from the first state to the second state at a second change point;
- a correction gate circuit for correcting a selected one of
- the commutation signal by setting a time difference of the commutation signal at the first change point and for outputting a corrected commutation signal, and
- the PWM signal by setting a time difference of the PWM signal at the second change point and for outputting a corrected PWM signal;
- and
- an inverter for supplying a drive signal to the motor in accordance the corrected commutation signal and the corrected PWM signal.
A method of controlling a motor, comprising the steps of:
- outputting a commutation signal in accordance with an axial position of the motor, wherein the commutation signal comprises first and second states, wherein the commutation signal changes from the first state to the second state at a first change point;
- generating a PWM signal, wherein the PWM signal comprises first and second states, wherein the PWM signal changes from the first state to the second state at a second change point;
- correcting a selected one of
- the commutation signal by setting a time difference of the commutation signal at the first change point and
- the PWM signal by setting a time difference of the PWM signal at the second change point,
- outputting a corrected commutation signal and a corrected PWM signal;
- and
- providing an inverter for supplying a drive signal to the motor in accordance the corrected commutation signal and the corrected PWM signal.
Dependencies are inferred from the claim text.