Current control loop for actuator and method
First Claim
1. A current control loop for an actuator, comprising:
- a current command controller setting a command current, the current command controller being configured to be coupled to a drive circuit used to drive the actuator,a sampling module sampling a motor current of the actuator, wherein the sampling module comprises a resistor coupled in series with low-side switches of the drive circuit of the actuator, wherein a voltage drop across the resistor is proportional to the motor current, and wherein the sampling module further includes a switch and a capacitor coupled in parallel with the resistor when the switch is on, a charge on the capacitor being proportional to the voltage drop across the resistor;
a summation module calculating a current error based on the motor current, wherein the current error is calculated by subtracting the motor current from the command current, and wherein the current error is used to compensate for an error in the motor current of the actuator; and
a limiter for limiting the command current so that the command current does not exceed a predetermined maximum command current value.
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Accused Products
Abstract
Systems and methods for providing a current control loop for an actuator. A typical system includes a current command controller setting a command current, the current command controller being coupled to a drive circuit used to drive the actuator and a sampling module sampling a motor current of the actuator. The system also includes a summation module calculating a current error based on the motor current, the current error being calculated by subtracting the motor current from the command current. The current error is used to compensate for an error in the motor current of the actuator. The sampling module can include a switch and a capacitor coupled in parallel with the resistor when the switch is on, a charge on the capacitor being proportional to the voltage drop across the resistor. Methods for setting a maximum control current and for providing the current control loop are also illustrated.
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Citations
5 Claims
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1. A current control loop for an actuator, comprising:
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a current command controller setting a command current, the current command controller being configured to be coupled to a drive circuit used to drive the actuator, a sampling module sampling a motor current of the actuator, wherein the sampling module comprises a resistor coupled in series with low-side switches of the drive circuit of the actuator, wherein a voltage drop across the resistor is proportional to the motor current, and wherein the sampling module further includes a switch and a capacitor coupled in parallel with the resistor when the switch is on, a charge on the capacitor being proportional to the voltage drop across the resistor; a summation module calculating a current error based on the motor current, wherein the current error is calculated by subtracting the motor current from the command current, and wherein the current error is used to compensate for an error in the motor current of the actuator; and a limiter for limiting the command current so that the command current does not exceed a predetermined maximum command current value. - View Dependent Claims (2, 3, 4, 5)
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Specification