Browse Prior Art Database

Motor Torque Control

IP.com Disclosure Number: IPCOM000078580D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Keidl, SD: AUTHOR [+3]

Abstract

Control over DC motor torque is provided by programming the current in the motor. The programming of current in the motor is accomplished by applying predetermined voltage waveforms as reference voltages, to a chopper motor drive circuit.

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Motor Torque Control

Control over DC motor torque is provided by programming the current in the motor. The programming of current in the motor is accomplished by applying predetermined voltage waveforms as reference voltages, to a chopper motor drive circuit.

Motor winding 15 is connected in the collector circuit of transistor T1, which forms part of chopper motor driver circuit 10. The base of transistor T1 is controlled by the output of Schmitt comparator 20, which has one input connected to the +V supply via sampling resistor RS and its other input connected to voltage waveform generator 25. Generator 25 provides the reference voltage for comparator 20. The particular waveform of the reference voltage depends upon the desired motor current and in turn the desired motor torque. Motor torque in general is directly proportional to motor current.

The current in motor winding 15 follows the voltage level provided by generator 25. In this manner, the acceleration and deceleration of the motor can be precisely controlled. A desired voltage waveform generated by 25 and applied to comparator 20 is shown in Fig. 2. Comparator 20 controls the base of transistor T1 whereby transistor T1 initially conducts when the voltage drop across RS is less than reference voltage VR, i.e., the voltage at the output of generator 25 referenced to the +V supply. As T1 conducts, current flow through RS and winding 15 increases to cause the voltage drop across RS, i.e., VRS to become great...