Pulse width modulated servo clutch driver
First Claim
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1. A system for controlling a solenoid, comprising:
- a voltage source connected to the solenoid;
a current sensor for sensing a current through the solenoid;
a switch for controlling the current through the solenoid; and
a processor connected to the voltage source, the current sensor, and the switch, wherein the processor is configured to generate a PWM signal for controlling the current through the solenoid, wherein the PWM signal is based on a first signal associated with the voltage source and a second signal associated with the current sensor.
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Abstract
Disclosed is a system and method for controlling a clutch associated with a solenoid using a pulse width modulated (PWM) signal, which keeps the current through the coil constant over a wide temperature range and fluctuations in line voltage. The system may include a voltage source, a switch (such as a FET), a current sensor, and a processor. The system controls the clutch by sampling the voltage source, sampling the current measured by the current sensor, and computing a duty cycle, which is then used to generate a PWM control signal.
17 Citations
20 Claims
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1. A system for controlling a solenoid, comprising:
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a voltage source connected to the solenoid;
a current sensor for sensing a current through the solenoid;
a switch for controlling the current through the solenoid; and
a processor connected to the voltage source, the current sensor, and the switch, wherein the processor is configured to generate a PWM signal for controlling the current through the solenoid, wherein the PWM signal is based on a first signal associated with the voltage source and a second signal associated with the current sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for controlling a solenoid, comprising:
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acquiring a line signal corresponding to a line voltage;
acquiring a sense signal corresponding to a current flowing through the solenoid;
estimating a resistance based on the line signal, the sense signal, and a previous duty cycle;
computing a duty cycle based on the estimated resistance; and
generating a pulse width modulated signal corresponding to the duty cycle. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A system for controlling a solenoid, comprising:
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means for providing a voltage;
means for sensing a current flowing through the solenoid;
means for switching current through the solenoid;
means for computing a duty cycle based on the voltage, the current, an estimated resistance, a previously estimated resistance, and a previous duty cycle; and
means for supplying a pulse width modulated signal to the means for switching current, wherein the pulse width modulated signal is based on the duty cycle.
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Specification