A Virtual Inductance Based Sliding Mode Control to Suppress Switching Frequency Circulating Current in Parallel Converters

In parallel operation of multiple inverters, switching frequency circulating current (SFCC) is generated between inverters due to the carrier phase difference. It will cause the distortion of output current waveform, and thus, the system loss is increased, and further affect the safety and stability of the system. In this paper, a virtual inductance based sliding mode control (SMC) method is proposed for the parallel converters to solve this problem. Particularly, a virtual inductance, which can simulate the effect of real ones without deteriorating the system volume and loss, is combining with SMC in this proposal to suppress the SFCC. The advantages of the proposed suppression scheme are easy implementation, low cost, and strong practicability. The effectiveness of the proposed solution is verified by the simulation studies in MATLAB/Simulink.