A single chip INTEL 8748 based Pulse Width Modulation system has been developed. Six PWM signals for three phase application are generated on PORT 1 by outputting DATAWORDs after a delay determined by DELAY-WORDs. Two different sets of DATAWORDs are used for forward and reverse motions. The PWM signals have been used to run two ac synchronous motors to control a tracking photovoltaic system. The motion of the tracker is decided by Input signals on BUS PORT and PORT 2 (UPPER). Bit 6 and 7 of PORT 1 and lower nibble of PORT 2 are used as gate signals for tri-state buffers to control two or more motors from one set of PWM signals.
"A Single Chip PWM Generator For Tracking Photovoltaic System", Proc. SPIE 0854, IECON '87: Motor Control and Power Electronics, (19 October 1987); doi: 10.1117/12.942980; https://doi.org/10.1117/12.942980