考虑中点电位平衡的三电平Boost-逆变器协调控制

针对常见的二级式三电平Boost-逆变器,为降低逆变器开关损耗,同时控制中点电位平衡,提出了一种空间矢量不连续调制及其中点电位平衡策略。基于电荷平衡原理,定量计算TL-Boost变换器电荷补偿量,推导变换器占空比调整量表达式,控制流经中点的总电荷量为零。通过两级系统协调控制,不仅可以发挥逆变器不连续调制低开关损耗的优势,同时还可以实现中点电位平衡控制,降低逆变器调制策略复杂度。最后,通过仿真验证了该控制策略的有效性。

Coordination Control of Three-level Boost-inverter Considering Neutral-point Potential Balance

In order to reduce the switching loss of the inverter and control the neutral-point potential balance,a novel discontinuous space vector modulation was proposed for the typical two stage TL-Boost converter and three-level inverter.Based on charge balance principle,the charge compensation of the TL-Boost converter was quantitatively calculated,and the adjustment of duty ratio was deduced,the total amount of charge flowing through the neutral-point was controlled to be zero.Through the coordinated control strategy of two stage,not only the advantage of the low-switching loss of the discontinuous modulation could be play,but also the neutral-point potential fluctuations was suppressed,and modulation complexity of inverter was reduced.Finally,the effectiveness of the control strategy was verified by simulation.