In a lot of automatic controling systems, the steady occurring three-phase PWM circuit is needed.This paper describes the new type occurning three-phase PWM circuit which the numeral IC HEF4752 is core, and introduces the mounts, the construction and function of the IC HEF4752. The construction of this circuit is very simple. The circuit is controlled easily and used expendiently. At last the software Protel 99SE is used to the draw the SCH and PCB. Although the system achieve only by the hardware , but the results showed that the main control to IC HEF4752 chip SPWM waveform generator is simple, low cost, performance, and debugging convenient, reliable operation.
Key words:HEF475 Frequency converted speed SPWM PCB