单相中点箝位开关电容多电平逆变器及其控制

Single phase neutral-point-clamped switched-capacitor multilevel inverter and its control

提出一种单相电压源中点箝位开关电容多电平逆变器,该逆变器利用直流母线箝位电容对电源电压进行分割,通过控制电源与电容的串并联实现逆变器多电平输出,并且可以通过扩展进一步提高逆变器的输出电平数量和电压增益。为实现电容的电压平衡,同时降低其电压纹波,逆变器的调制过程考虑了开关的冗余状态,且开关管之间互补工作,调制策略简单。对所提逆变器的工作原理、调制策略、电容电压及相关参数进行了详细分析,并给出了拓扑结构的扩展方法。最后,分别通过仿真和实验,对所提逆变器的稳态性能和动态性能进行了验证。

A single phase voltage source neutral-point-clamped multilevel inverter with switched capacitors is proposed.The DC bus clamped capacitors are configured to segment the power supply voltage,and the multilevel voltage output can be achieved by controlling the connection of power supply and capacitors in series or parallel.In addition,the output level quantity and voltage gain of the inverter can be further increased through an expansion mechanism.In order to achieve the voltage balance of the capacitors and reduce their voltage ripples,the redundant switch states of the inverter are considered during the modulation process.The switches work in a complementary way,and therefore,the modulation strategy is simple to implement.The working principle,modulation strategy,capacitor voltage and related parameters of the proposed inverter are analyzed,and the topology extension mechanism is given.Finally,the steady performance and dynamic performance of the proposed inverter are verified by simulation and experiment.