Method and apparatus for driving a brushless direct current motor
First Claim
1. An apparatus for driving a brushless direct current motor, comprising:
- a commutation circuit coupled to a power supply;
a feedback element;
an input interface configured for providing at least a user determined speed input; and
a control circuit coupled to the commutation circuit, the input interface and the feedback element, wherein the control circuit is configured to receive inputs from the input interface and the feedback element, and generate control signals readable by the commutation circuit, the commutation circuit configured to generate a pulse width modulation for driving the motor, the pulse width modulation comprising;
a first voltage pulse configured to generate a motor current of a reference current value sufficient to achieve a desired speed according to the user determined speed input; and
subsequent pulses of the voltage configured to maintain the motor current substantially within a determined range of the reference current value.
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Accused Products
Abstract
A method for driving a DC motor includes generating a first voltage pulse, based on a pre-determined speed input and duty cycle, and configured to generate motor current of reference current value sufficient to achieve a desired speed according to the speed input. Subsequent pulses of the voltage are generated to maintain the current substantially within a range of the reference current. Another method includes sensing and comparing motor current to reference current value and generating an error signal therebetween, which is integrated over time to generate an integrated current error, which is compared with a reference pulse. Thereafter generating applied voltage pulses configured to: switch at each instance of the integrated current error exceeding or becoming less than the reference pulse value; generate a motor current sufficient to achieve a desired speed according to a pre-determined speed input; and having substantially zero average variation from the reference current.
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Citations
24 Claims
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1. An apparatus for driving a brushless direct current motor, comprising:
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a commutation circuit coupled to a power supply; a feedback element; an input interface configured for providing at least a user determined speed input; and a control circuit coupled to the commutation circuit, the input interface and the feedback element, wherein the control circuit is configured to receive inputs from the input interface and the feedback element, and generate control signals readable by the commutation circuit, the commutation circuit configured to generate a pulse width modulation for driving the motor, the pulse width modulation comprising; a first voltage pulse configured to generate a motor current of a reference current value sufficient to achieve a desired speed according to the user determined speed input; and subsequent pulses of the voltage configured to maintain the motor current substantially within a determined range of the reference current value. - View Dependent Claims (2, 3)
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4. A method for driving a brushless direct current motor, comprising:
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generating a first voltage pulse In the motor based on a user determined speed input and a determined duty cycle, wherein the first voltage pulse generates a motor current of a reference current value sufficient to achieve a desired speed according to the user determined speed input; receiving a feedback signal representative of a difference between the reference current value and the motor current; and generating subsequent pulses of the voltage based at least in cart upon the feedback signal, the subsequent pulses configured to maintain the motor current substantially within a determined range of the reference current value. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for driving a brushless direct current motor, comprising:
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a commutation circuit coupled to a power supply; a first feedback element; a second feedback element; an input interface configured for providing at least a user determined speed input; and a control circuit coupled to the commutation circuit, the input interface, the first and the second feedback elements, wherein the control circuit is configured to receive inputs from the input interface and the first and second feedback elements, and wherein the control circuit generates a pulse width modulation for driving the motor, the pulse width modulation comprising; generating applied voltage pulses, the applied voltage pulses configured to switch at each instance of a current error integrated over time becoming less than a reference pulse value and the current error integrated over exceeding the reference pulse value, and the applied voltage pulses further configured to generate a motor current sufficient to achieve a desired speed according to a user determined speed input wherein the generated motor current has a substantially zero average variation from a reference current value. - View Dependent Claims (15, 16, 17)
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18. A method of driving a brushless direct current motor, comprising:
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sensing a current in the motor; comparing the motor current to a reference current value; generating an error signal representing the difference between the reference current value and the motor current; integrating the error signal over time to generate a current error integrated over time; comparing the current error integrated over time with a reference pulse; and generating applied voltage pulses, the applied voltage pulses configured to switch at each instance of the current error integrated over time becoming less than the reference pulse value and the current error integrated over time exceeding the reference pulse value, and the applied voltage pulses further configured to generate a motor current sufficient to achieve a desired speed according to a user determined speed input, wherein the generated motor current has a substantially zero average variation from the reference current value. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification