无差调频过程中微电源功率分配策略设计

Design of a Power Distribution Strategy for Microsources During Zero-error Frequency Regulation Process

微电网孤网运行时不同的微电源具有不同的调频特性,基于下垂控制的逆变器接口型微电源能根据运行要求自动分配扰动功率,但稳态时频率存在静态偏差。在下垂控制中加入积分控制可实现逆变器的无差调频,维持微电网的稳态频率恒定,但扰动功率全部由含积分控制环节的逆变器承担。针对这种无差调频控制策略,设计了逆变器的传递函数,通过数学推导验证了无差调频的有效性,并进一步得到了无差调频型微电源的功率分配策略。基于MATLAB/Simulink仿真平台,验证了理论分析的正确性和有效性。

Different microsources have different frequency regulation functions when the mierogrid is islanded. The droop con trol inverters can distribute the disturbed power among the microsources according to the operation demand; however, the steady state frequency often deviates from the rated value because of the droop characteristics. By adding the integral control to the droop control algorithm, the inverter can regulate the frequency without frequency error; but the disturbed power is under- taken only by the microsources which have the integral control. The transfer function of the inverter is designed based on the zero-error frequency regulation control strategy, and then the frequency restoration function is verified through mathematical derivation. Furthermore the power distribution strategies of the rnicrosources with zero error frequency regulation functions are studied. Finally, a simple microgrid is modeled based on MATLAB Simulink platform, and the simulation results are coinci dent with the theoretical analysis results, which validates the validity and effectiveness of the above conclusions.