双低压单元混合级联逆变器的改进载波层叠调制策略

传统的载波层叠调制方法应用于双低压单元混合级联逆变器时，存在低压单元之间功率不平衡问题。为此，本文提出了一种改进的载波层叠调制策略。该策略首先通过传统的混合载波层叠调制方法产生各个开关管的驱动信号，然后再对开关管的驱动信号进行功率平衡优化后得到开关管的实际驱动信号。仿真结果表明：该策略能够在逆变器高压单元工作在基波频率的情况下，解决逆变器电流倒灌问题和实现两个低压单元的功率平衡，使得逆变器输出相电压的谐波主要为以mf为中心的边带谐波。

An Improved Carrier Stack Modulation Strategy for Dual Low-voltage Unit Hybrid Cascaded Inverter

When the conventional carrier stack modulation method is applied to a dual low-voltage unit hybrid cascade inverter, there is a power imbalance problem between the low voltage units. For this reason, this paper proposes an improved carrier stack modulation strategy. The strategy firstly generates the driving signal of each switch through the traditional mixed carrier stack modulation method, and then obtains the actual driving signal of the switch after power balance optimization of the driving signal of the switch tube. The simulation results show that this strategy can solve the reverse current problem and realize the power balance of the two low-voltage units when the inverter high-voltage unit operates at the fundamental frequency, which makes the output voltage harmonics of the inverter is mainly sideband harmonics centered on mf.