基于Lyapunov间接法分析的恒功率负载电源变换器宽稳定控制策略

A Novel Wide Stability Control Strategy of Constant Power Load Power Converter Based on the Analysis of Lyapunov Indirect Method

在航空航天供电系统中,随着变换器负载和电动机负载的不断增加,恒功率负载在用电设备中所占的比重越来越大。这种负载因内部闭环控制而呈现恒功率特性,是导致系统不稳定的主要原因之一。而应用于航空航天的独立电源变换系统,由于受到体积和重量的限制,对变换器的设计提出了更高的要求。本文提出一种基于前级电感电流的高频分量直接注入占空比的补偿方法,不仅可以减小供电系统中母线滤波电容尺寸,还能使因恒功率负载造成的不稳定现象得到抑制,提高系统稳定工作范围。以现代飞机直流供电系统中常见的Boost变换器为例,建立系统的状态空间模型,并利用Lyapunov间接法分析系统的稳定性,最后给出仿真及实验结果,验证了所提控制策略的正确性和可行性。结果表明,采用这种占空比补偿技术可在相同功率输出条件下,减少约8倍的母线滤波电容。

In aerospace power supply system,with the increasing of the power converter loadsand motor loads,constant power loads in the proportion of electricity equipment are growing.Becauseof the internal closed-loop control of this kind of loads,constant power loads show the constant powercharacteristic.This characteristic is one of the main causes of the system instability.Moreover,due tothe size and weight limits,this kind of independent power supply system used in aerospace putsforward higher requirements for the design of the converter.A method of direct injecting highfrequency components is presented in this paper based on inductor current to the duty cycle.Thismethod not only reduces the size of filter capacitor,but also suppresses the instability caused byconstant power loads.In this paper,the Boost converter designed for aircraft application is taken as anexample.The state space model of the system is established,and the stability of the system is analyzedby Lyapunov.At last,the simulation and experimental results prove the correctness and feasibility ofthe proposed control strategy.In the same power output condition,this duty cycle compensation technology can reduce the filter capacitance by about8times.