Virtual synchronous generator (VSG) control strategy is widely used for photovoltaic grid-tied inverter to provide better stability for low inertia green energy generation. However, due to the fluctuation of photovoltaic output, the traditional virtual synchronous machine control strategies with constant power reference cause significant fluctuations in the DC side voltage, which does harm to the stable operation of the system. Energy storage equipment is generally used to stabilize the DC bus voltage, which imposes high cost to the customer, especially for the distributed roof photovoltaic generation. To deal with this problem, the active power reference of the VSG is regulated using the proportional integral (PI) control framework according to the error between the DC bus voltage reference and the measured DC bus voltage. To accelerate the regulation speed, a set of fuzzy rules are proposed to adjust the proportional integral parameters, which also avoid the difficulty in the traditional PI parameter adjustment. Simulation results show the effectiveness of the DC side voltage stabilization method, and the improved performance using the fuzzy interference parameter adjustment for PI controller.