基于单极倍频SPWM调制的单相Buck-Boost集成式升压逆变器研究

Research on Single Phase Buck-Boost Integrated Step-up Inverter With Monopole Frequency Doubling SPWM Modulation

为满足低输入电压逆变场合的要求,提出了一种单相Buck-Boost集成式升压逆变器。其通过复用电压型全桥逆变器下管的体二极管以及上开关管,将两个Buck-Boost变换器和全桥逆变器集成在一起,与其他单级式升压逆变器相比,具有功率器件少、结构简单、集成度高等优点。另外,其采用传统的单极倍频SPWM调制,仅通过调节调制比(M<1)就能同时实现升压和逆变,因此控制非常方便,且输出电压/电流的总谐波失真均较低。首先介绍了该逆变器的拓扑演化过程;然后分析了直流升压电感电流连续和断续两种模式下的工作原理,并结合伏秒平衡和积分变换理论,推导出电压增益、功率管电应力等稳态特性和升压电感设计准则;最后通过一台250W/10k Hz的样机进行了仿真和实验验证。

To be suitable for the low input voltage applications, a novel single phase Buck-Boost integrated step-up inverter is proposed in this work. The proposed inverter integrates two Buck-Boost converters and the voltage source inverter by sharing the upper switch and the body diode of the down switch. Compared with other single-stage step-up invertcrs, it has the advantages of simpler topology and higher integration. Besides, it adopts the monopole frequency doubling SPWM modulation, and so can boost and inverter the input voltage simultaneously just by regulating the modulation ratio （M〈 l）. Apart from the easier control, the total harmonic distortion （THD） of output voltage/current can also be reduced benefiting from this modulation method. At fn＇st, the topology evolution process of the inverter was illustrated. Then, the operation principles were analyzed in detail. Based on these, the voltage gain, electrical stress of power device and the design guideline of the boost inductor were derived with the theories of volt-second balance and integral trans-formation. At last, the validity and effectiveness of the proposed inverter had been verified by the simulation and experiment results of a 250W/10kHz prototype.