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Abstract

A motor velocity control system employing feedback to maintain actual motor rotational velocity at or near a desired rotational velocity implements a clock rate control motor rotational velocity system by advantageously apportioning the required functions between a relatively small, slow speed microprocessor, and a plurality of discrete circuit elements in the form of analog and digital logic devices. The microprocessor serves the following four general functions: (1) as a 'basic clock' timer of variable rate to set up motor speed; (2) as a relatively slow speed determiner of when various components are to be switched for commutation, and for indicting to an integrator circuit which motor winding is currently unenergized and which therefore may be sampled for determining rotor actual position; (3) as a digital feed to a digital to analog (D/A) converter for setting a motor winding current limit; in accordance with the principles of the Alley; and (4) as a communication link to receive velocity and direction commands, preferably in the form of a plurality of points defining a waveform profile or envelope. Discrete analog and digital logic elements are employed to implement the functions of analog integration and comparison with the integral limit, as well as current comparison and chopper control.

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First Claim