基于PWM逆变电路供电的永磁同步电机电压和电流的谐波通用型新算法

A Universal and New Harmonic Algorithm of Voltage and Current of Permanent Magnet Synchronous Motors Supplied By PWM Inverter

根据PWM逆变电路的工作原理和永磁同步电机特性,提出了一种能够考虑实际开关器件特性的永磁同步电机电压和电流谐波通用计算方法。该算法分析了PWM波形的通断时刻、基波周期与PWM逆变电路的调制方法、调制方式的数学关系,推导出电压谐波计算公式,然后结合负载类型和控制策略,又推导出了电流谐波计算公式。为验证该算法,先后搭建了电机及控制系统的Matlab/SIMULINK仿真模型和实验测试装置平台,进行了相关的仿真和实验研究,考虑到仿真数据和实测数据的离散性,采用离散傅里叶变换(discrete Fourier transform,DFT),将得到的DFT谐波与计算值进行对比,结果相互吻合,证明了理论分析的正确性。

According to the working principle of PWM inverter circuit and the characteristic of permanent magnet synchronous motors（PMSM）, a new and versatile algorithm considering the actual switching device characteristics was proposed, which was applied in the harmonic calculation of PMSM voltage and current. The mathematical relation was analyzed between on-off time and the fundamental period of the PWM waveform and modulation method and mode of the PWM inverter circuit, and the expressions of PMSM voltage harmonics were derived. Secondly, combining with the type of load and control strategy, the calculation formula of PMSM current harmonics were also deduced. In order to validate the algorithm, Matlab/SIMULINK simulation model and experimental device platform of the motor and control system were built, and related simulation and experiments was made. Taking the discreteness of simulated data and measured data into account, the discrete Fourier transform（DFT） was introduced. The DFT were compared with simulation and experiment, they have better agreement, and the validity of the theoretical analysis was proved. The algorithm flow is clear and simple, and it is still practical.