混合钳位式三电平变流器控制方法研究

Study on Control Method of Hybrid-clamped Three-level Inverter

分析了混合钳位式三电平逆变器的4种开关工作状态及其钳位桥臂内侧功率开关器件关断过电压的原理,对其64种电压空间矢量在不同功率因数情况下对中点电位的影响特性进行分析,并给出了独特的中点电位平衡调制策略;在对钳位电容电压充、放电过程分析的基础上,针对不同能量流动方向,分别提出了利用开关状态切换的方式实现钳位电容电平衡的调制策略,并给出了详细的电压空间矢量优化选择方法。设计了基于TMS28335+XinlinxCPLD/FPGA的控制电路和主电路,验证了其钳位机制的正确性及调制方法的有效性。

The four switches working states of hybrid-clamped three-level inverter and emplacement principle of switching-off over-voltage for its power switch device inline clamping bridge arm were analyzed.The effects of 64 kinds of voltage space vectors on the mid-point potential under different power factors were analyzed and a unique mid-point potential equilibrium modulation strategy was given.Based on the analysis of the clampingcapacitor charging and discharging circuit under different energy flow directions,the clamping-capacitor voltage balance modulation strategy using state-level switching means was put forward.And the SVPWM optimization algorithm was established in detail.Also,the control circuit and main circuit based on TMS28335+Xinlinx CPLD/FPGA was designed,which validates the correctness of the embedding mechanism and validity of modulation strategy.