Development of a fuzzy-Q control for achieving robust inverter systems

This paper presents analysis and design control scheme including the nonlinear effects of the output-filter inductor and active switches of the inverter systems. Since the filter inductance will drop dramatically when the inverter system is operated at heavy loads, system dynamic performance will vary over a wide range. Q-parameter is selected as an input variable of the control scheme to improve the system performance. The dc link of the inverter system is a constant value, but the variation of the modulation will also affect the linear control of the system. The reference command of an inverter system is a sinusoidal wave. In the paper, a nonlinear controller is used to compensate the nonlinear results of the sine-modulated inverter during each cycle. Inverter systems with the proposed control scheme can compensate the influence due to variations of filter inductance and nonlinear effect of the active switches no matter it operated at the light loads or the heavy loads. Thus, a robust inverter system can be achieved.