Research On The Control Strategy Of The Micro-grid Inverter Uses The Theory Of Zero-error Frequency And Adaptive Voltage Regulation

The microgrid is the important way of developing renewable energy, improving the power supply reliability and expanding capacity of power supply system, also, the stability control of the microsource (namely, MS) is one of the key questions. The problem of static frequency deviation and fixed voltage droop coefficient of the droop control is analyzed and studied in this paper based on the conditions of impedence and load changes.The integral part was used to realize the zero-error frequency regulation and maintain the constant steady-state frequency aimed at solving the problem of static frequency deviation at the steady-state with the droop control. Also, the impedence voltage droop compensation term and quadratic function type voltage droop coefficient related to the active and reactive power are used to compensate the voltage droop, regulate the droop amount dynamically and reduce the voltage amplitude deviation and the effect of the control parameters and system parameters on the load sharing performance, aiming at solving the problem of serious voltage amplitude deviation caused by the fixed voltage droop coefficient with different loads and the bad load sharing performance. The control strategy of zero-error frequency regulation with PI regulator and adaptive voltage regulation control with quadratic function is analysed and studied in this paper, and the power distribution strategy is investigated according to the transfer function of the MS controller. Meanwhile, the static frequency deviation and voltage droop amount is within the limit by the validation of the system simulation used the Matlab/Simulink.The microgrid experimental platform with3inverters of3kVA using digital control is built after the analysis and research of the zero-error frequency and adaptive voltage regulation control. The experiments of the zero-error frequency regulation and adaptive voltage regulation control realized by the PI regulator and quadratic function in the conditions of line impedence and load changes are completed to validate the superiority of the control strategy in the frequency and voltage regulation aspects.