易于FPGA实现的最优移相PWM控制策略

在综合考虑波形特性、开关损耗、电压利用率及易实现性的基础上，提出一种新的最优移相脉宽调制(PWM)控制策略。从线电压出发，指出电压利用率的提高实质上是一个非线性规划问题，并就此非线性规划问题分8种情况进行讨论，系统地分析了谐波注入正弦脉宽调制(SPWM)电压利用率可以达到的极限值。采用数字仿真得出易于现场可编程门阵列(FPGA)实现的最优移相PWM调制波数据，并对其进行频谱分析。论证了移相法和堆波法在开关损耗上的一致性，以及移相法具有开关动作均匀、易于FPGA实现的特点。最后给出了最优移相PWM策略MATLAB仿真波形以及在SIGA(system in gate array)多电平高压变频器模型机中应用的实验波形。

OPTIMAL PHASE-SHIFTING MULTILEVEL PWM FOR FPGA IMPLEMENTATION

A novel optimal phase-shifting multilevel PWM algorithm is developed with a balanced consideration of four factors including less harmonic contents, lower switching frequency, fuller DC voltage utilization and easier realization. The algorithm treats the DC voltage utilization as a nonlinear planning problem and the solution is found for 8 cases. Fourier analysis is also made of the optimal modulating waveforms. This paper compares the phase-shifting technique and carrier-based technique to show the advantages of the former. The algorithm is successfully integrated in the FPGA with the prototype machine and output waveform examples also presented.