Electrical wave synthesizer for controlling an electric motor

Abstract

A control signal for the drive of a synchronous motor is synthesized in response to direction of rotation and speed digital input signals. The synthesizer includes up-down counters for counting the speed input signal and a toggle circuit tracks the repetitive count of the counters. A digital to analog converter converts the count to an analog current. Distortion of the analog current can be provided to match the motor characteristics and to compensate for temperature variations. The distorted analog current is applied to an operational amplifier which has a non-linear feedback circuit including serially connected resistors and serially connected diodes with each resistor shunted by a diode to limit voltage drop thereacross. A multiplexer receives the output from the operational amplifier and provides the output control signal.

Dependencies are inferred from the claim text.