三电平逆变器SHEPWM技术的所有解问题  

Complete Solutions for SHEPWM of Three-level Inverter

作　　者：叶满园 李宋 蔡鸿 

机构地区：[1]华东交通大学电气与自动化工程学院,南昌330013

出　　处：《电力系统及其自动化学报》2017年第10期18-21,29,共5页Proceedings of the CSU-EPSA

基　　金：国家自然科学基金资助项目(51167006);江西省工业科技支撑计划资助项目(20161BBE50057);江西省自然科学基金资助项目(20161BAB206157);江西省教育厅自然科学基金资助项目(GJJ160495)

摘　　要：针对多电平逆变器特定谐波消除SHEPWM(selective harmonic elimination pulse-width modulation)求解非线性方程组对开关角度初值依赖性高的问题,采用三角函数倍角关系将三电平中点钳位NPC(neutral pointclamped)逆变器SHEPWM非线性方程组转换为代数多项式的模式,并利用MATLAB中的Solve函数对多项式模型进行求解,在无需开关角初值的情况下得到了全调制比下的所有解。给出了开关角及线电压谐波失真THD(total harmonics distortion)随调制比变化的轨迹,分析和比较了开关角解的分布特点,为实际工程中开关角度的选取提供了理论依据。最后仿真和实验验证了利用Solve函数所求开关角度的正确性和可行性。Aiming at the problem that the selective harmonic elimination pulse-width modulation(SHEPWM)of amulti-level inverter has a high dependence on the initial values of switching angle in the solving process of nonlinearequations,double-angle trigonometric functions are used in this paper to convert the nonlinear equations of SHEPWMof three-level neutral point clamped(NPC)inverter into an algebraic polynomial mode,and all the solutions in fullmodulation region can be obtained by using the'Solve'function in MATLAB to process the polynomial model withoutthe need to know the initial values of switching angle. The trajectories of switching angles and the corresponding totalharmonic distortion(THD)of line voltage,which vary with the modulation ratio,are also given. Moreover,the distribu-tion characteristics of the solutions of switching angles are analyzed and compared,which provides a theoretical refer-ence for the selection of switching angles in practical engineering. Finally,the correctness and feasibility of using the'Solve'function to compute the switching angles is verified by simulations and experiments.

关 键 词：三电平逆变器 代数多项式 消谐模型 开关角初值 

分 类 号：TM464[电气工程—电器]