三相电压源型逆变器的多目标满意优化脉宽调制策略

Pulse Width Modulation Strategy for Three-phase Voltage Source Inverters Based on Multi-objective Satisfactory Optimization

提出了一种基于伏秒平衡方程组特解在线规划的新型多目标满意脉宽调制策略(multi-objective satisfactory optimization PWM,MSO-PWM)。首先,针对单个载波周期内线性调制范围扩展、输出电流纹波损耗与开关损耗3个优化目标分别建立了时域数学规划模型,并求解各自的全局最优解,实现了单个目标的全局最优化。通过对3个目标的全局最优解的分析,揭示了不同优化目标之间矛盾的本质原因,通过引入满意优化的思想,以多目标满意取代单目标最优,并通过目标满意度松弛避免了因目标矛盾而出现的无解问题,最终实现了3个目标的整体满意优化。相对于现有的单目标局部优化PWM,所提出的MSO-PWM能够根据决策者偏好信息通过调整开关损耗系数界限来灵活地调整各控制目标的重要性,在偏重优化某个目标的同时兼顾其他目标,实现多个目标的满意优化,以满足现代逆变器系统越来越多的设计要求,具有很强的通用性和灵活性。实验结果验证了MSO-PWM的正确性与灵活性。

This paper proposed a programmed pulse width modulation strategy for two-level voltage source inverters based on the on-line programming of the special solutions of the volt-second balance equations with multi-objective satisfactory optimization（MSO-PWM）. The global optimum special solutions for the targets that linear modulation range extension, current ripple losses minimization and switching losses minimization were respectively obtained by solving the established mathematic programming model. Meanwhile, the contradiction between different targets was analyzed in nature. The satisfactory optimization with the process of relaxing the satisfying degree of single object was introduced to avoid the insoluble phenomenon caused by the contradiction, thus realizing the three-objective satisfactory optimization. Compared to the existing local optimization pulse width modulation strategies, the MSO-PWM can adjust the importance of single objective flexibly by selecting an appropriate switching loss coefficient limitation according to the preference of the decision maker to satisfy the demand of different fields, which make it universal and flexible. In addition, MSO-PWM can give consideration to other targets when focus on the most important target, thus, it can achieve multi-objective satisfactory optimization. Experimental results show that the proposed strategy is effective and flexible.