Improving Transient Response of VSG Controlled Grid-Tied Converter

Distributed generators based on Virtual Synchronous Generator (VSG) control strategy reduce the maximal frequency deviation at the cost of increasing power oscillation. Different with a real synchronous generator, parameters and the swing equation of VSG can be modified flexibly to enhance the transient response of VSG. In this paper, a modified VSG (VSG-MD) control strategy based on low pass filter modified moment of inertia is proposed to cope with above oscillation issue. Besides, the parameter design principle of the proposed modified VSG control strategy is given according to the swing equation frequency characteristic. The experimental results show that the performance of proposed modified VSG method is improved in contrast with traditional ones: the power response overshoot is decreased from 66.7% to 23.1% and the frequency deviation peak is lowered from 0.115 Hz to 0.094 Hz. It is beneficial to improve both the performance of frequency deviation suppression and power regulation by the proposed modified VSG method.