变频空调中数字式PFC电路设计与应用

针对数字式升压PFC电路在多联机变频空调中的应用,对常规同步电路进行了改进,有效地抑制了来自逆变电路的干扰;通过优化控制方法,减轻微处理器(MCU)的负担,实现了用一个MCU同时实施PFC和逆变控制,并根据系统的运行状态灵活、及时地调整PFC的控制特性.实验结果表明,新的同步电路工作稳定,电源输入功率因数高,波形良好;直流母线电压在各种负载情况下均保持稳定,空调系统的制冷/制热能力得到显著提高.

Design and Application of Digital Boost PFC Circuits for Variable-speed Air-conditioning Systems

For the application of digital Boost Power Factor Correction(PFC) circuits to variable-speed multi air-conditioning systems,an improved synchronizing circuit which can resist the disturbance from the inverter is proposed in this paper.With the optimized control law,it is possible to use a single microprocessor to execute both the PFC control and the inverter control.The characteristics of the PFC control can be adjusted flexibly and rapidly according to the operating status of the system.Experimental results show that the proposed circuit works very well,and the input current has a sinusoidal waveform with unity power factor.The DC bus voltage is kept in a high level under different load conditions,so the cooling/heating capacity of the air-conditioning system is greatly improved.