Circuitry and method for driving a motor
First Claim
1. Circuitry for driving a motor by PWM (Pulse Width Modulation) control, comprising:
- switching means respectively associated with drive coils, which are included in the motor and assigned to a particular phase each;
frequency oscillating means for generating a triangular wave;
first comparing means for generating a pulse sequence by comparing the triangular wave and a voltage for PWM oscillation frequency modulation;
position sensing means for sensing angular positions of the motor;
pulse generating means for counting a preselected number of pulses, which are included in the pulse sequence, by using each of positive-going edges and negative-going edges of position signals output from said position sensing means as a trigger to thereby generate pulse signals;
voltage adjusting means for converting a voltage for duty modulation to a plurality of voltage levels;
voltage selecting means for selecting one of the plurality of voltage levels in accordance with the pulse signals output from said pulse generating means, and outputting a voltage level selected as a duty modulation voltage;
second comparing means for outputting a first duty signal by comparing the voltage for duty modulation and the triangular wave;
third comparing means for outputting a second duty signal by comparing the duty modulation voltage output from said voltage adjusting means and the triangular wave; and
exciting pulse generating means for generating, based on the position signals output from said position sensing means and the first and second duty signals, a gate signal for switching control for a preselected period of time at each time of phase switching, wherein said gate signal includes a signal for reducing noise of the motor.
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Accused Products
Abstract
In circuitry for driving a motor 9 by PWM (Pulse Width Modulation) control. a pulse sequence Spwm is generated on the basis of a triangular wave TR that is control led by a capacitor. The pulses of the pulse sequence Spwm are counted in synchronism with position signals U1, V1 and W1 output from position sensing means, which is responsive to the angular positions of the motor 9, so that a duty modulation signal Sduty-b is generated for reducing noise ascribable to the rotation of the motor 9. An exciting pulse generating circuit 8 switches a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) circuit 11 with gate signals Q1P through Q3P and Q1N through Q3N.
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Citations
116 Claims
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1. Circuitry for driving a motor by PWM (Pulse Width Modulation) control, comprising:
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switching means respectively associated with drive coils, which are included in the motor and assigned to a particular phase each;
frequency oscillating means for generating a triangular wave;
first comparing means for generating a pulse sequence by comparing the triangular wave and a voltage for PWM oscillation frequency modulation;
position sensing means for sensing angular positions of the motor;
pulse generating means for counting a preselected number of pulses, which are included in the pulse sequence, by using each of positive-going edges and negative-going edges of position signals output from said position sensing means as a trigger to thereby generate pulse signals;
voltage adjusting means for converting a voltage for duty modulation to a plurality of voltage levels;
voltage selecting means for selecting one of the plurality of voltage levels in accordance with the pulse signals output from said pulse generating means, and outputting a voltage level selected as a duty modulation voltage;
second comparing means for outputting a first duty signal by comparing the voltage for duty modulation and the triangular wave;
third comparing means for outputting a second duty signal by comparing the duty modulation voltage output from said voltage adjusting means and the triangular wave; and
exciting pulse generating means for generating, based on the position signals output from said position sensing means and the first and second duty signals, a gate signal for switching control for a preselected period of time at each time of phase switching, wherein said gate signal includes a signal for reducing noise of the motor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A method of controlling rotation of a motor by executing PWM control over switching devices associated with drive coils each of which is assigned to a particular phase of said motor, said method comprising the steps of:
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(a) causing a frequency oscillator to generate a triangular wave and comparing said triangular wave and a voltage for PWM oscillation frequency modulation to thereby output a pulse sequence;
(b) counting a preselected number of pulses included in the pulse sequence by using each of negative-going edges and positive-going edges of position signals output from position sensing means, which is responsive to angular positions of the motor, as a trigger to thereby output pulse signals;
(c) converting a voltage for duty modulation to a plurality of voltage levels;
(d) selecting one of the plurality of voltage levels in accordance with the pulse signals, and outputting a voltage level selected as a duty modulation voltage;
(e) outputting a first duty signal by comparing the voltage for duty modulation and the triangular wave;
(f) outputting a second duty signal by comparing the duty modulation voltage and the triangular wave; and
(g) generating a gate signal in accordance with the position signals output from said position sensing means and the first and second duty signals. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116)
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Specification