Control of single-phase parallel-connected inverters: fixed-frequency quasisliding mode control approach and FPGA-based implementation

A fixed-frequency quasisliding control algorithm is reported and applied to the design of an inverter system of N parallel-connected single-phase inverters. This algorithm is implemented into a FPGA device, which also includes the implementation of a power management strategy according to the load power demand. Experimental results for three inverters are provided to illustrate the features of the design in terms of AC output voltage regulation, balanced current-sharing, fixed-frequency operation and robustness in front of load variations.