The Research Of PFC Technology Based On Half-Bridge PWM Rectifier

The grid harmonic pollution is increasing with high power electronic devices used widely in the power grid, which causes low power factor and makes the energy utilization efficiency reduced. Therefore great attention has been given to increase PF and suppress harmonic in the world. Some key technology about PFC has been researched in this thesis: software phase locked technology, the principle and application of half-bridge PWM rectifier and the design of dual boost PWM rectifier.The key to get high Power Factor (PF) is to control input current in phase with input voltage, so phase locked technology is very important. Three software phase locked methods are studied based on TMS320F2812DSP in this thesis: zero adjustment of pointer, phase adjustment after frequency adjustment, the phase and frequency simultaneous adjustment, and the experimental comparison is also given in such aspects as application field, the DSP resource requirement, the phase locked velocity and so on. Half-bridge PWM rectifiers have the advantages of high PF, low harmonic pollution, bidirectional power flow and so on. The principle of half-bridge PFC circuit, the problem of unbalance in capacitor voltages and the influence on output ripple are analyzed in detail. Furthermore, the solution for this problem is presented, and a 1kW prototype is designed to realize experimental verification. At last, a kind of dual boost PWM rectifier is researched, and a 1kW experiment prototype is also designed and experimental results verify that dual boost PWM rectifier can not only get higher conversion efficiency and higher PF, but also get more enhanced reliability.