Real-time digital control of PWM inverter with fuzzy logic compensator for nonlinear loads

An algorithm which applies a fuzzy logic compensator to real-time control of the single-phase PWM (pulse-width-modulated) inverter for UPS (uninterruptible power supply) application is described. Using the state variables measured at each sampling time, the controller calculates the inverter pulse width for the next sampling time. The next interval pulse width is computed to eliminate the pulse width limitation due to the computation time of the microprocessor. A fuzzy logic controller is used to compensate for the voltage drop due to nonlinear loads. The proposed control scheme is verified by simulations for nonlinear load conditions, sudden load changes, and system parameter variations. The performance of the proposed scheme is shown to be excellent.<>