This paper proposes a fuzzy control scheme for the closed-loop regulation of a PWM inverter in application of high-performance ac voltage regulators (AVR) and uninterruptible power supplies (UPS). According to the observed and simulated dynamic behaviors of an ac power source under various load conditions, an innovative fuzzy control scheme is proposed. The PWM pattern is determined at every sampling instant by a decision table which is defined by the fuzzy control rules. To verify the proposed fuzzy control scheme, a DSP-based (TMS320C14) fuzzy controller with sampling rate of 4 KHz has been implemented. The constructed DSP-based fully digital-controlled PWM inverter system has fast dynamic response and low total harmonic distortion (THD) for phase-controlled nonlinear load.