Method and apparatus for controlling a motor
First Claim
Patent Images
1. A method of driving an n-phase DC motor, where n>
- 1, comprising the steps of operating a central processing unit (CPU) to generate a motor speed command signal in accordance with a predetermined programmed set of instructions;
converting said motor speed command signal to a motor drive signal;
selecting a respective phase of said DC motor to be energized;
applying DC power to the selected phase as a function of said motor drive signal;
supplying to said CPU signals representing the position or speed of said DC motor;
operating said CPU to detect both rapidly changing and slowly changing errors in the actual speed of said DC motor;
operating said CPU in accordance with a first set of instructions to modify said motor speed command signal by an amount tending to reduce rapidly changing detected speed errors; and
operating said CPU in accordance with a second set of instructions to modify said motor speed command signal by an amount tending to reduce detected slowly changing speed errors.
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Abstract
An n-phase DC motor is controlled by converting a motor speed command signal generated from a programmed CPU to a motor drive signal and using this motor drive signal to apply DC power to a selected phase of the motor, the amount of applied DC power being a function of the value of the motor speed command signal. Signals representing the position and/or speed of the motor are supplied to the CPU from which the CPU detects speed errors. The speed command signal then is modified to speed up or slow down the motor so as to reduce the detected errors.
64 Citations
33 Claims
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1. A method of driving an n-phase DC motor, where n>
- 1, comprising the steps of operating a central processing unit (CPU) to generate a motor speed command signal in accordance with a predetermined programmed set of instructions;
converting said motor speed command signal to a motor drive signal;
selecting a respective phase of said DC motor to be energized;
applying DC power to the selected phase as a function of said motor drive signal;
supplying to said CPU signals representing the position or speed of said DC motor;
operating said CPU to detect both rapidly changing and slowly changing errors in the actual speed of said DC motor;
operating said CPU in accordance with a first set of instructions to modify said motor speed command signal by an amount tending to reduce rapidly changing detected speed errors; and
operating said CPU in accordance with a second set of instructions to modify said motor speed command signal by an amount tending to reduce detected slowly changing speed errors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- 1, comprising the steps of operating a central processing unit (CPU) to generate a motor speed command signal in accordance with a predetermined programmed set of instructions;
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16. A method of driving an n-phase DC motor, where n>
- 1, comprising the steps of operating a central processing unit (CPU) to generate a motor speed command signal in accordance with a predetermined programmed set of instructions;
converting said motor speed command signal to a motor drive signal;
selecting a respective phase of said DC motor to be energized;
applying DC power to the selected phase as a function of said motor drive signal;
supplying to said CPU signals representing the position or speed of said DC motor;
operating said CPU to detect errors in the actual speed of said DC motor;
operating said CPU to modify said motor speed command signal by an amount tending to reduce detected speed errors; and
braking said DC motor when electrical power is interrupted, including storing a DC voltage level during the time period that power is applied, and using said stored DC voltage level to turn on phase selecting FET devices and shunt all of the n phases of said DC motor to a reference potential through said FET devices when said electrical power is interrupted.
- 1, comprising the steps of operating a central processing unit (CPU) to generate a motor speed command signal in accordance with a predetermined programmed set of instructions;
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17. Apparatus for controlling an n-phase DC motor comprising:
- a programmed central processing unit (CPU) for generating a motor speed command signal;
converting means for converting said motor speed command signal to a motor drive signal;
switch means responsive to said motor drive signal for switching DC power to a respective phase of said DC motor;
index signal generating means for generating index signals as said DC motor operates and for supplying said index signals to said CPU;
said CPU being programmed to respond to said index signals for detecting both rapidly changing and slowly changing errors in the actual speed of said DC motor;
said CPU being programmed in accordance with a first set of instructions to modify said motor speed command signal by an amount that tends to reduce said radpily changing errors; and
said CPU being programmed in accordance with a second set of instructions to modify said motor speed command signal by an amount that tends to reduce said slowly changing errors. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- a programmed central processing unit (CPU) for generating a motor speed command signal;
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32. Apparatus for controlling an n-phase DC motor comprising:
- a programmed central processing unit (CPU) for generating a motor speed command signal;
converting means for converting said motor speed command signal to a motor drive signal;
switch means responsive to said motor drive signal for switching DC power to a respective phase of said DC motor;
index signal generating means for generating index signals as said DC motor operates and for supplying said index signal to said CPU;
said CPU being programmed to respond to said index signals for detecting errors in the actual speed of said DC motor and to modify said motor speed command signal by an amount that tends to reduce said errors;
means for supplying respective commutating pulses to said switch means to select a corresponding phase of said DC motor for energization, whereby DC power is switched through said switch means to the selected phase in accordance with the value of the motor drive signal; and
wherein said switch means comprises n FET devices and a bipolar transistor, said FET devices being connected in common with said bipolar transistor, each FET device being connected to a respective phase of said DC motor and being rendered conductive by a respective commutating pulse, and said bipolar transistor being responsive to said motor drive signal to thereby determine the current that flows through the conductive FET device and a respective phase. - View Dependent Claims (33)
- a programmed central processing unit (CPU) for generating a motor speed command signal;
Specification