单周期控制PFC变换器电流相位滞后及其补偿

Current Phase Lag Compensation for One Cycle Controlled PFC Converter

研究了单周期控制功率因数校正变换器的输入等效电路,指出了单周期控制功率因数校正变换器存在相电流滞后于相电压的基波相移问题。结合输入等效电路提出了控制开关管端电压以减小基波相移的电流滞后相位补偿方案,推导了不同基波相移时开关管端电压应满足的幅值及相位条件;在此基础上,结合单周期控制功率因数校正变换器的数字控制方案,给出了补偿方案的实现方法及设计实例,并研究了采用补偿方案时系统的稳定性。论文建立的输入等效电路能更准确地反映单周期控制功率因数校正变换器的输入特性;实验验证了提出的电流相位滞后补偿方案能够减小基波相移量,提高基波位移因数。

A new equivalent input circuit of one-cycle-controlled（OCC） PFC converter is built, based on which,the current phase lag issue especially at low ratio of switching frequency to line frequency is analyzed,and a novel current phase lag compensation scheme by controlling the voltage across the switch is proposed to reduce the phase lag of line current relative to line voltage.Implementation method of the compensation scheme with digital control is introduced,and a design example is given.The stability of the system using the compensation scheme is verified by frequency-domain analysis.The newly built equivalent input circuit can more preciously reflect input characteristics of the OCC PFC converter,and the proposed compensation scheme can reduce the current phase lag,and improve the power factor,which is verified by experimental results.