Sliding-mode control design applied to parallel-connected modular inverters through FPGA-based implementation

A sliding-mode control strategy based on a Lyapunov function approach is reported and applied to the design of a modular system of m parallel-connected single-phase inverters. This strategy is implemented by means of a field programmable gate array (FPGA) device which also includes a module operation supervision (MOS) block supporting power management, fault-tolerant and module operating time-sharing algorithms. Experimental results for three parallel-connected inverters are presented to illustrate the design features in terms of AC output voltage regulation, inverters current distribution, robustness in the presence of load variations and to show the proper operation of the MOS block.