串并联双降压半桥逆变器输入电压脉动的分析

串并联双降压式半桥逆变器可输出多种规格的电网电压,应用在并网逆变器场合可提高其通用性。由于该逆变器存在串联和并联两种工作模式,因而会引起双降压式半桥逆变器总的输入电压脉动和两个输入分压电容的电压脉动。阐述了该逆变器的工作原理,分析了其在串、并联两种工作模式下对输入电压脉动的影响。分析结果表明,输入分压电容电压脉动与输出视在功率成正比,与输出电压频率、输入分压电容容值和输出电压有效值成反比。仿真分析和实验结果验证了理论分析的正确性。

Analysis of Input Voltage Ripple of Cascading/Parallel Dual-Buck Half-bridge Inverter

Cascading/parallel dual Buck half-bridge inverter can put out multiple voltages,so is very suitable for grid-connected inverter.The universality of the grid-connected inverter can be improved.But it exists two operation modes which can affect the input voltage ripple and voltage ripple of input capacitors.The operation principle is illustrated,and the input voltage ripple at cascading and parallel modes is analyzed.Analysis results indicate that the voltage ripple of two input capacitors is proportional to the output apparent power,and is inverse proportional to the values of input capacitors, the frequency and root mean square(RMS) of the output voltage.Experimental results verify the theoretical analysis.