三电平逆变器SHEPWM牛顿下山法求解研究

SHEWPM of Three-level Inverter Based on Newton Downhill Method

针对采用牛顿-拉夫逊(N-R)法求解三电平中点箝位型(NPC)逆变器选择谐波消除脉宽调制(SHEPWM)非线性方程组时初始值存在选择困难的问题,提出了一种基于牛顿下山法的SHEPWM方程组计算方法。通过合理选取下山参数,新方法可有效克服N-R法中迭代初始值对最优解的近似要求。以7个开关角的NPC逆变器SHEPWM为例进行计算和实验分析,结果表明新方法放宽了对迭代初始值的选取要求。

For the difficulty of choosing the iterative initial values when solving the selective harmonic elimination pulse width modulation （SHEPWM） nonlinear equations used Newton-Raphson （N-R） method in neutral-point-clamped （NPC） inverter, a novel method based on Newton downhill method is presented.By reasonable selection of the downhill parameters, this method can effectively overcome the strict requirements of the iterative initial values in N-R method.The results of a case study with the SHEPWM for NPC inverter show that the proposed method can be used to achieve excellent convergence properties than that by N-R method.Finally,the calculation results are confirmed by experimental results.