混合级联H桥逆变器的调制策略优化方法  

Modulation Strategy Optimization Method of Hybrid Cascaded H-bridge Inverter

作　　者：顾军[1] 宋飞 李平[1] 李登魁 许天 史泓 GU Jun;SONG Fei;LI Ping;LI Dengkui;XU Tian;SHI Hong(School of Electrical and Information Engineering,Auhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学电气与信息工程学院,淮南232001

出　　处：《高电压技术》2022年第2期753-761,共9页High Voltage Engineering

基　　金：国家自然科学基金(51607003)。

摘　　要：多低压单元的混合级联H桥逆变器在电平切换时由于具有更多冗余开关状态,通过多载波移幅法对低压单元调制能很好地解决电流倒灌问题,但多载波移幅法由于自身特点存在级联单元输出功率不均衡、逆变器输出电压等效开关频率不高等不足。为此,针对直流侧电压比1:1:2的混合级联九电平逆变器,提出一种脉冲宽度调制与阶梯波调制相结合的混合调制策略,使得高压单元工作在基频状态,低压单元通过类似单极性倍频的混合调制法工作在高频,提高了逆变器输出电压的等效开关频率,同时低压单元采用1/4周期循环调制的方法在半个周期内实现低压单元间输出功率均衡,并通过仿真和实验结果分析验证了理论分析的可行性和正确性。Hybrid cascaded H-bridge inverters with multiple low-voltage cells have more redundant switching states during level switching.The carrier amplitude shift method can well solve the current backflow problem for low-voltage cells modulation.However,due to its own characteristics,the multi-carrier amplitude shift method has the disadvantages of unbalanced output power of cascaded cells and low equivalent switching frequency of inverter output voltage.For this reason,for the hybrid cascaded nine-level inverter with a DC side voltage ratio of 1:1:2,a hybrid modulation strategy combining PWM modulation and ladder wave modulation was proposed to enable the high-voltage cells to work in the fundamental frequency state,and to enable the low-voltage cells to work at high frequency through a hybrid modulation method similar to unipolar frequency multiplication,which improved the equivalent switching frequency of the inverter output voltage.At the same time,the low-voltage cells adopted a 1/4 cycle cyclic modulation method to realize the low-voltage cells within half a cycle.The output power was balanced between the two,and the feasibility and correctness of the theoretical analysis were verified through simulation and experimental results analysis.

关 键 词：混合级联逆变器 载波移幅 等效开关频率 1/4周期循环 功率均衡 

分 类 号：TM464[电气工程—电器]