基于虚拟阻尼补偿的恒功率负载系统控制方法

摘要

电动机负载广泛存在于各个工业领域，其闭环控制对前级功率系统表现为恒功率负载（ constant power loads， CPL ）特性，即负阻抗特性，给系统带来了稳定性的影响。针对基于前置BUCK变换器的电动机驱动系统稳定性问题进行了研究。首先对基于前置BUCK变换器的电机驱动系统进行了建模，分析了影响系统稳定性的机理，在此基础上提出了一种基于虚拟阻尼补偿的控制策略，这种方法可以在不增加系统损耗的前提下有效抑制负阻抗特性对直流母线电压的影响，并给出了补偿系数的设计流程。仿真和实验证明这种方法提高了系统稳定性，增加了电机驱动系统稳定带载的能力。%The motor loads, existing in many industrial fields, behave as constant power loads ( CPLs) with negative incremental impendence which may destabilize the system when tightly regulated.In this paper, the stability of BUCK converter with constant power load ( CPL) is studied.The model of the mo-tor driving system based pre-BUCK converter was established.The mechanism of the stability impact of the system was analyzed.A new control scheme of neutralizing the negative impedance degenerating the bus voltage based virtual damping compensation was proposed, and the process of compensating coeffi-cient design was given.The simulation and experimental results demonstrate that the proposed method im-proves the stability of the system with constant power loads.