摘要
分布式电源主要通过逆变器接入微电网,逆变器控制技术在微电网中具有重要地位。下垂控制可以自动调节功率且灵活性强,在微网协调控制中得到了广泛的应用。提出了一种新型下垂控制方法,该方法对传统下垂控制的电压电流控制环、功率控制环2个环节进行改进,即：对电压电流控制环,加入了动态虚拟阻抗反馈,实现了有功功率和无功功率的解耦,从而保证了逆变器输出阻抗与线路阻抗相匹配;对功率控制环,除了构造了积分环节以提高系统稳态性外,还将频率差值、电压差值通过PI控制来修正下垂系数,以使系统能随着系统运行情况而做自适应的调整,从而增强了频率和电压的动态稳定性。最后通过软件仿真和硬件实验验证了所提控制策略的有效性和可行性。
Distributed power supply is typically connected to microgrid via inverter, and inverter control technology plays an important role in microgrid. Droop control, widely used in microgrid coordination control, can automatically adjust power with strong flexibility. In this paper, a new droop control method is proposed to improve two links of traditional droop control： voltage-current control loop and power control loop. A dynamic virtual impedance feedback is added to voltage-current control loop to achieve decoupling between active power and reactive power, thus ensuring match between inverter output impedance and line impedance. For power control loop, this paper constructs an integral part to improve system stability. Frequency difference and voltage difference are controlled with PI control to correct droop coefficient, so that the system can perform adaptive adjustment according to system conditions, enhancing dynamic stability of frequency and voltage. Finally, effectiveness and feasibility of the proposed control strategy are verified with simulation and experiment.
出处
《电网技术》
EI
CSCD
北大核心
2018年第1期203-209,共7页
Power System Technology
基金
国家自然科学基金(61573239)
上海市重点科技攻关计划(14110500700)~~
关键词
孤岛运行
并网逆变器
下垂控制
虚拟阻抗
功率控制
电压电流控制
islanding operation
grid-connected inverter
droop control
virtual impedance
power control
voltage-current control
