摘要
并联逆变器需要较强的环流抑制能力、较好的功率分配特性和一定的抗扰能力。而传统下垂控制与双环控制方法动态特性较差、功率分配精度不高、环流抑制效果一般。针对低压微网系统稳定运行受逆变器输出阻抗、连线阻抗、负荷特性影响等复杂情况,详细分析了逆变器的应用需求,重点研究了环流抑制和功率均分控制策略,提出了一种含虚拟负感抗分量和自适应虚拟阻抗的多环控制策略,采用负感抗分量抵消逆变器输出阻抗中的感性成分,利用自适应虚拟阻抗动态调节逆变器连线阻抗参数,从而使逆变器输出等效阻抗在较宽频带下呈现阻性特性,简化了繁杂的解耦控制算法。此外,为解决虚拟阻抗与电压跌落的矛盾问题,重新设计了下垂控制外环,提高了功率分配精度和动态响应速度。PSCAD/EMTDC建模仿真与实验测试结果表明,所提控制策略合理可行,预期在微网系统和光伏电站中具有广阔的推广应用前景。
Parallel inverters require stronger circulating current suppression capabilities,excellent power distribution characteristics,and certain anti-interference capabilities.However,the traditional droop control and dual-loop control method have poor dynamic characteristics,low power distribution accuracy,and low circulation suppression effects.The stable operation of low-voltage microgrid system is affected by inverter output impedance,wiring impedance,and load characteristics.In response to these issues,we first analyze the application requirements of the inverter in detail,focusing on circulating current suppression and power sharing control strategy.On this basis,we propose a multi-loop control strategy with virtual negative inductance component and adaptive virtual impedance.This control strategy uses the negative inductance component to cancel the inductive component in the inverter output impedance,and dynamically adjusts the inverter wiring impedance parameters through adaptive virtual impedance.The superiority of this method is that the inverter output equivalent impedance exhibits resistive characteristics in a wider frequency band and simplifies the complicated decoupling control algorithm.In addition,we redesign the sag control outer loop to solve the voltage dip problem caused by virtual impedance and improve the power distribution accuracy and dynamic response speed.The simulation on PSCAD/EMTDC and experimental results demonstrate effectiveness of the proposed scheme.It is expected to have a wide range of applications in microgrid systems and photovoltaic power plants.
作者
张继红
赵锐
刘云飞
杨培宏
吴振奎
张新
ZHANG Jihong;ZHAO Rui;LIU Yunfei;YANG Peihong;WU Zhenkui;ZHANG Xin(Inner Mongolia Key Lab of Solar Thermal and Wind Power,Inner Mongolia University of Science and Technology,Baotou 014010,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第1期136-146,共11页
High Voltage Engineering
基金
国家自然科学基金(62063026)
内蒙古自治区关键技术攻关项目(2019GG319)
内蒙古自治区自然科学基金(2021MS05039)。
关键词
低压微网
并联逆变器
自适应虚拟阻抗
多环控制
环流抑制
功率分配
low-voltage microgrid
parallel inverter
adaptive virtual impedance
multi-loop control
circulation suppression
power distribution
