High frequency and precision 3-phase sine/PWM controller with near-zero frequency of MPU intervention

Conventional PWM fully depends on microprocessors for extensive online computation, intervention and house-keeping. At a 20 kHz switching frequency, a modern CPU's overhead increases up to 90%. Conventional methods also have a poor cycle-to-cycle accuracy of /spl plusmn/5-10 /spl mu/sec and a limited frequency range. A novel self-managed high frequency PWM controller is developed to meet these increasing demands. The architecture permits a near-zero interfacing rate with the MPU whilst being capable of both asynchronous and synchronous PWM over a range of 0-1000 Hz, expandable to several kHz. A cycle-to-cycle accuracy of 50 nsec is achievable. Experimental results verify this new approach.