H桥逆变器输入电压纹波分析及最小输入电容设计

Input Voltage Ripple Analysis and Minimal Input Capacitance Design of H-bridge Inverter

以H桥逆变器的输入电容为研究对象,采用基波等效分析法推导了通过输入电容的电流,给出了输入电压纹波的解析式及最小输入电容的设计算式。最后,完成了1台34.5 kV·A的H桥逆变器样机的设计,设计电压纹波系数为5%,输入电容采用3个15 000μF/400 V的铝电解电容并联实现。样机满载稳定运行,实测纹波电压系数为4.32%,电容表面的平均温升为10.8℃。实验结果验证了所提出的设计方法的有效性。

The input capacitor of H-bridge inverter was studied, the current of input capacitor was derived by applying fundamental harmonic approximation. The analysis formula of input voltage ripple and design equation of minimal input capacitance were proposed. Finally, a 34.5 kV · A prototype was build, and the input capacitor was obtained by paralleling three 15 000 μF/400 V aluminum electrolytic capacitor under theoretical 5% voltage ripple. The prototype run stably, the voltage ripple is 4.32% and the average temperature rise of the capacitor surface is 10.8 ℃. The experiment verifies the feasibility of the proposed design method.