With the steady penetration of inverters

the switching harmonics caused by power electronic devices will bring about adverse effect to the microgrid. When many inverters are connected in parallel

the high harmonics can either be injected into its own AC filter capacitor or into AC filter capacitors of other inverters. The high harmonics will accumulate randomly for lack of coordinated control among pulse width modulation(PWM)signals. And the high order harmonics can reduce the lifetime of AC filter capacitors. An attenuation method of high harmonic current for filter capacitors based on global synchronous pulse width modulation is proposed. Firstly

the high harmonics injection principle of AC filter capacitors is deeply analyzed and the basic principle of attenuation method of high harmonic current for capacitors based on global synchronous pulse width modulation is proposed. Secondly

the general formulas of calculating high harmonics flowing into capacitors are derived. Thirdly

mathematical expressions are chosen appropriately and the optimal solution of phase shift angles among distributed inverter is obtained. Finally

simulation results are presented to verify the performance of the proposed method.