NPC/H_5L逆变器共模电压抑制策略研究

Study on Common Mode Voltage Suppression Strategy of NPC/H_5L Inverter

针对中点箝位/H桥5电平(NPC/H5L)逆变器在基于有限控制集模型预测控制(FCS-MPC)的共模电压(CMV)抑制中存在运算量大、权重因子整定困难问题,通过g,h坐标系下的逻辑开关矢量优化选择,在满足电压跳变限制条件下实现了相邻矢量的统一逻辑选取,从而避免了复杂的查表运算,并将预测运算量降低到4~7次;引入满意优化思想,通过开关损耗和CMV抑制指标的"满意"代替"最优",实现了无权重因子控制器设计;最终,实现了冗余矢量的最小CMV输出控制。通过模型仿真与DSP+FPGA实验平台,对所提策略的动态性能、总谐波畸变率与开关频率在全电流调制度范围内的分布规律及与电感电阻比、基波频率、采样频率等参数的关系进行了详细分析,仿真实验验证了所提控制策略的特点及可行性。

In order to solve the problems of large computation and difficult adjustment of weight factor in the common mode voltage(CMV)suppression of neutral-point-clamped/H bridge5 level(NPC/H5 L)inverter based on the finite control set model predictive control(FCS-MPC),by optimizing the selection of logic switch vectors in g,h coordinate system,the unified logic selection of adjacent vectors is realized under the condition of meeting the voltage jump limitation,thus avoiding the complex table lookup operation,reducing the prediction operation to 4~7 times.By introducing the idea of satisfactory optimization,the controller design without weight factor is realized by replacing the"optimal"with the"satisfactory"of switch loss and CMV rejection index.Finally,the minimum CMV output control of redundant vector is realized.Through model simulation and DSP+FPGA experimental platform,the dynamic performance,total harmonic distortion and switching frequency in the full current modulation range,and the relationship with ratio between inductance and resistance,fundamental frequency,sampling frequency and other parameters are analyzed in detail.Simulation and experiment verify the characteristics and feasibility of the proposed control strategy.