含自适应虚拟电容控制的直流母线电压综合控制策略

Integrated Control Strategy of DC Bus Voltage with Adaptive Virtual Capacitor Control

由于直流微电网广泛采用传统下垂控制,因而在恒功率负荷扰动时,系统存在母线电压变化速度快、振荡、偏移大等问题,不利于电压敏感负荷的正常运行。为解决上述问题提出一种由改进的自适应虚拟电容控制(improved adaptive virtual capacitor control,IAVCC)、振荡抑制器和电压补偿器组成的直流母线电压综合控制策略。其中,IAVCC在负荷扰动时可根据母线电压变化率自适应地调节虚拟电容大小,从而增强直流微电网惯性,减缓母线电压变化速度,改善系统动态特性。在此基础上,振荡抑制器通过滤除母线电压的高频振荡分量,显著地抑制了电压振荡。此外,电压补偿器可实现母线电压无偏差调节,解决了负荷功率增加时母线电压跌落严重的问题。所提出的综合控制策略实现了直流母线电压动态特性优化、振荡抑制以及无偏差调节,改善系统动态性和稳定性。最后通过基于RTLAB的实验验证所提策略的可行性。

Due to the widespread use of traditional droop control in DC microgrids,the system suffers from rapid DC bus voltage changes,oscillations and large excursions during constant power load disturbances,which is detrimental to the proper operation of voltage-sensitive loads.To solve the above problems,the paper proposes an integrated control strategy for the DC bus voltage,consisting of the improved adaptive virtual capacitor control(IAVCC),oscillation suppressor and voltage compensator.In particular,IAVCC adaptively adjusts the virtual capacitor according to the bus voltage change rate during load disturbance,enhancing system inertia of DC microgrid to slow bus voltage changes and improve system dynamic characteristics.On this basis,the oscillation sup⁃pressor significantly damps out the voltage oscillation by filtering out the high-frequency oscillation component of the bus voltage.In addition,the voltage compensator enables deviation-free regulation of the bus voltage,solving the problem of severe bus voltage dips when the load power increases.The proposed integrated control strategy achieves optimization of the dynamic characteristics of the DC bus voltage,oscillation suppression,and deviation-free regulation.Finally,the feasibility of the proposed strategy is proven by RT-LAB-based experiments.