DIGITAL PULSE WIDTH INVERTER CONTROL SYSTEMS

摘要

A control system for controlling the conduction period of the switching elements of a pulse width control type inverter is provided having a reference pulse generator that determines the output frequency of the inverter output voltage, a constant voltage control circuit for generating an analogue output voltage, an A-D converter for converting the analogue output voltage into a digital output signal and a up-counter which counts clock pulses. The outputs of the up-counter and the A-D converter are compared with each other by a digital comparator. The up-counter is cleared by the reference pulse when another up-counter counts a predetermined number of output pulses from the comparator. The up-counter repeats a predetermined number of counting up and clearing operations until it produces a carry signal, and the conduction period of the switching element is determined by an internal between the generation of the reference signal and the generation of the carry signal. In a modified embodiment the up-counter is substituted by a down counter. The control system has an excellent transient response for external disturbances simplified and rugged construction, and can operate accurately without being affected by the errors of electronic circuit components comprising the control system.