SINGLE PHASE HALF-BRIDGE INVERTER BASED ON PWM METHOD FOR PIEZOELECTRIC MICRO-FLOW ACTUATOR

摘要

This paper focuses on an integrated single phase, half-bridge voltage inverter that uses the standard DC power supply to output an adjustable frequencies signal to drive the micro-flow actuator. Pulse width modulation(PWM) plays a predominant role in the DC-AC power converter control and has been widely used. Ideally, the electrical signals what we need are purely sinusoidal. As for PWM, it does not only include the fundamental sin-wave frequency, but also include harmonic disturbances. So a lot of researches focus on the elimination of harmonic. In this paper, two widely used methods for voltage harmonic elimination in pulse width modulation are discussed. One is SPWM, and the other is SHE-PWM. They both have some advantages and disadvantages.But their combination is an effective way of broadening the frequencies range of output sin-wave signal and also make the design of filter simpler. Then a synthetic method is proposed and with this method, the needed single-phase half-bridge inverter is designed based on microcontroller of TMS320F2812 to drive the piezoelectric micro-flow actuator. Finally the experimental implementation demonstrates that by filtering the harmonic, the output PWM signal can be transformed to good sine waveform signal at a wide frequencies range.