级联H桥多电平逆变器的新型SHEPWM开关方案

A Novel Switching Scheme of SHEPWM Controlled for Cascaded H-bridge Multi-level Inverter

级联H桥多电平逆变器因其不存在电容电压均压问题,且各单元结构相同,易于模块化和扩展,具有电压冗余等特点,而得到了广泛应用。此处针对其多波段调制模式及特定谐波消除脉宽调制(SHEPWM)传统开关方案存在功率不平衡问题,提出一种新的开关方案,该开关方案利用相电压冗余性,调整B,C波段模式调制下各单元电平输出。新开关方案使各波段输出功率更均衡,理论分析和实验验证了该开关方案相对传统方案的优越性,对级联型多电平逆变器具有一定的实际意义。

Cascaded multilevel inverter is widely used for it does not existing the problem of capacity voltage balancing and it＇s easy to modularize and expand.Aiming at the power unbalanced problem of multiband modulation mode and selective harmonic elimination pulse width modulation（SHEPWM） tradition switching scheme,a novel switching scheme using the redundance of output phase voltage is advanced,which adjusted the output level in each unit modulating under B and C band mode.The power of each H-bridge is more close to be balanced via the new technology.The theoretical analysis and experiment has certified it excellence compared to the traditional scheme,which means a certain degree to cascaded multilevel inverters in practical application.