This paper introduces an advanced approach to achieve real and reactive power control in grid-connected three-phase inverters under unbalanced grid conditions. A novel Proportional-Integral-Resonant (PIR) control strategy is proposed, aiming to address two primary objectives: maintaining balanced grid currents and point of common coupling voltages (PCC), while simultaneously injecting the grid with the desired real and reactive power. Comparative analyses with conventional Proportional-Integral (PI) and Proportional-Resonant (PR) controllers are conducted. The PI controller exhibits a better transient response and lower steady-state error compared to the PR controller. However, under unbalanced grid conditions, the PI controller exhibits oscillations in the real and reactive power output. In contrast, the PR controller effectively manages unbalanced situations and maintains power control. Thus, the proposed PIR method combines the advantages of both PI and PR controllers: superior transient response and lower steady-state error of PI, and effective handling of unbalanced conditions and power control of PR. The simulation and Hardwre’s experimental validation confirm the efficacy of the proposed method.

This study investigates the reduction of torque ripple in Permanent Magnet Synchronous Motors (PMSMs) during open-circuit fault (OCF) conditions using an adaptive Proportional-Integral-Resonant (PIR) control approach. Torque ripples, commonly exacerbated by faults in motor operation, result in undesirable vibrations, noise, and mechanical stress, thereby impacting the motor’s performance and longevity. The proposed PIR control method integrates a resonant controller with a conventional PI-current controller to enhance torque ripple suppression during OCF operation. Experimental validation, conducted using a dSPACE DS1104 platform, focuses on reducing torque ripple during OCF events. The results show that the adaptive PIR control method significantly reduces torque ripples, thus promoting smoother motor operation, increased efficiency, and increased reliability under fault conditions.

The three-phase grid system can become unbalanced for reasons such as single-phase loads and single-phase renewable energy sources connected to the grid. This unbalance not only affects inverter operation, but also impacts other loads connected to the grid. The traditional control methods for three-phase grid-connected inverter operation such as the proportional-integral (PI) control and proportional-resonant (PR) control have been used for balanced system conditions. The technique proposed here utilizes a PR controller to balance the grid currents while simultaneously injecting a commanded power into the grid. Simulation and experimental results confirm the effectiveness of this control method.

Presented in this paper is a method to use a three-phase inverter to inject currents to balance the grid currents while supplying power to the grid. The reference currents for the inverter are determined from the negative/zero sequence components of the measured load currents using a time-domain symmetrical components extraction method. Under the existence of unbalanced conditions, the proposed method corrects the unbalanced grid currents while simultaneously supplying the commanded power to the grid. The simulation and experimental results validate the performance of this proposed method.