本文对双变换UPS中双闭环电流跟踪控制的单相半桥PWM整流器进行了分析研究.为了减小输入电流的畸变,提出了稳态二次谐波补偿的算法.该方法可以不减小电压环带宽,同时计算工作量小,易于数字实现.为消除单相半桥整流器电容电压的不平衡,提出了电容电压分时控制的算法.基于TMS320LF2407A型DSP搭建了实验样机,验证了控制方法的正确性,由于采用有源功率因数校正技术,实现了输入电流为与输入电压同相的正弦波,且输出电压稳定.
In this paper, the dual closed-loop control principle of a single-phase half-bridge current -controlled PWM rectifier for the double conversion UPS is analyzed. A steady-state second-harmonic compensation method for the singlephase half-bridge PWM rectifier is proposed. It can eliminate the influence of the second harmonics in output voltage without reducing the bandwidth of the voltage feedback loop. This method needs only little program resources and computation, and is easy to be realized in a DSP controller. To ensure the capacitor voltage balancing, a time-sharing control scheme is proposed. A prototype is built based on TMS320LF2407A, and experiment results verify the effectiveness of the steady-state second-harmonic compensation method and the capacitor-voltage time-sharing control scheme. The input current waveform is shaped as a sinusoidal in phase with the input vohage by adopting the active power factor correction technique, and the output DC voltage is stable. Both the dynamic response and steady state performance are desirable.