Device and method for measuring and controlling the speed and torque of a DC motor
First Claim
1. A device for controlling the speed of a DC motor, wherein the speed of the DC motor is calculated in the device using determinations of motor field flux and armature voltage in the motor, the device comprising:
- a control module having one or more control inputs and one or more control outputs;
at least one control input is configured to receive data representing field current measured in the DC motor;
the control module includes flux curve logic that is responsive to measurements of motor field current to calculate a field flux in the motor, the flux curve logic using a flux curve stored in the control module, the flux curve representing a functional relationship between field current and field flux in the motor;
wherein the flux curve is defined by a plurality of flux curve data points corresponding to a plurality of motor field currents within a lower current range and within an upper current range; and
wherein the flux curve is further defined by at least a first flux curve line positioned within the lower current range and a second flux curve line positioned within the upper current range.
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Accused Products
Abstract
A DC motor control device calculates motor speed using determinations of motor field flux and armature voltage in the motor. The device includes a control module having one or more control inputs and one or more control outputs. At least one control input is configured to receive data representing field current measured in the DC motor. The control module includes flux curve logic that is responsive to measurements of motor field current to calculate a field flux in the motor. The flux curve logic uses a flux curve stored in the control module, the flux curve representing a functional relationship between field current and field flux in the motor. The flux curve is defined by a plurality of flux curve data points corresponding to a plurality of motor field currents within a lower current range and within an upper current range. The flux curve is further defined by at least a first flux curve line positioned within the lower current range and a second flux curve line positioned within the upper current range.
22 Citations
15 Claims
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1. A device for controlling the speed of a DC motor, wherein the speed of the DC motor is calculated in the device using determinations of motor field flux and armature voltage in the motor, the device comprising:
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a control module having one or more control inputs and one or more control outputs; at least one control input is configured to receive data representing field current measured in the DC motor; the control module includes flux curve logic that is responsive to measurements of motor field current to calculate a field flux in the motor, the flux curve logic using a flux curve stored in the control module, the flux curve representing a functional relationship between field current and field flux in the motor; wherein the flux curve is defined by a plurality of flux curve data points corresponding to a plurality of motor field currents within a lower current range and within an upper current range; and wherein the flux curve is further defined by at least a first flux curve line positioned within the lower current range and a second flux curve line positioned within the upper current range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of using a motor control device to control the speed of a DC motor comprising:
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defining a flux curve representing a functional relationship between field current and field flux in the motor using a plurality of flux curve data points stored in the motor control device; using the motor control device to operate the motor at a defined minimum field current; monitoring for oscillations in the speed of the motor; adjusting a value of at least one of the stored flux curve data points to reduce oscillations in the speed of the monitor; storing the adjusted value of the flux curve data point to modify the flux curve defined in the motor control device; measuring the field current during operation of the motor by the motor control device; using the measured field current and the defined flux curve to calculate a field flux in the motor; using the calculated field flux to determine the speed of the motor. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification