On zero steady-state error of single-phase PWM inverters voltage control and phase-locked loop system

This paper compares different control schemes for single-phase PWM inverter to achieve zero steady-state error under large varying load conditions. PR control and load current feedback control improve the steady-state and transient performance respectively. However, the load current feedback control is subject to control stability issue under some load conditions. The PR and synchronous d-q frame control using one type of ldquoimaginaryrdquo component generation method in both current and voltage loops are equivalent. A novel d-q frame control strategy is then proposed eliminating the need for the imaginary component intrinsically. This approach is also applied to a new single-phase PLL system with zero steady-state error.