Field-oriented control (FOC) has achieved great success in permanent magnet synchronous motor (PMSM) control. For the PMSM drive, FOC allows the motor torque and flux to be controlled separately, which means the torque and flux are decoupled from each other. Since the torque control is achieved by the speed controller, it can be considered that the speed and the flux of the PMSM are also decoupled from each other and can be controlled separately. In this paper, we propose a PMSM vector control using decoupled speed and flux controllers based on the proportional-resonant (PR) control method. A flux controller is proposed to control the flux of the PMSM and generate the d-axis reference current, whereas the speed regulator is used to generate the torque as well as the q-axis reference current. The PR controller is proposed to control the dq-axis currents and generate the reference voltages; its design is included.Therefore, decoupled speed and flux controllers are controlled separately using the PR controller. The Matlab/Simulink environment is utilized for the simulation, while the dSPACE DS1104 is used for the experimental work. The proposed control method is simple; there are no flux or torque estimators required, so it can avoid the complexity of estimators in the control scheme. The motor is tested under different scenarios, including flux change, speed change, and load torque change. The simulation and hardware results show the effectiveness of the proposed control method in controlling the the speed and the flux of PMSM with fast motor response and good dynamic performance in the different scenarios.

Under balanced three-phase system conditions, various conventional control methods were applied for controlling a grid-connected three-phase inverter, such as proportional-integral (PI) controller and proportional-resonant (PR) controller. The grid can become imbalanced for a variety of causes, including single-phase loading and single-phase renewable energy sources, impacting inverter operations and other grid-connected load. The PI control method functions poor in an unbalanced three-phase system, as illustrated by a current oscillation. This paper describes a method for converting an unbalanced three-phase system into three balanced components: positive, negative, and zero sequence, utilizing a time-domain symmetrical component extraction method. The symmetrical components currents are controlled by the PI controller. This system is simpler to use than other ways reported in the literature because it only requires one phase-locked loop.

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.

Proposed in this article is bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid conditions using a proportional-resonance controller. Different unbalanced grid conditions have been studied, such as unbalanced three-phase load and unbalanced grid impedance. These unbalanced scenarios generate unbalanced grid currents and unbalanced point-of-common-coupling (PCC) voltages, causing large oscillations in both real and reactive power transferred to the grid. The purposes of the suggested technique are to balance the grid currents and point-of-common-coupling voltages as well as control the power injected into the grid. As a result, balanced PCC voltages are guaranteed, the oscillation in real and reactive power is reduced, and power control is achieved. The proposed method’s performance has been verified in MATLAB/SIMULINK simulation software, and different experimental results have been obtained using a real-time interface platform, dSPACE DS1202.

rid-connected voltage-source inverters (VSI) have evolved in the past years for the interconnection of renewable energy sources with the grid to satisfy the increased electrical load demand and to utilize the use of clean, carbon-free energy. However, VSIs suffer from a major drawback of switching harmonics caused by the inverter switches. To reduce the amount of current distortion injected into the utility grid and meet harmonic constraints as defined by power quality standards, an LCL filter is often used. Although there is an extensive amount of literature describing the design procedures of an LCL filter, all these methods cannot guarantee an optimal solution because no direct mathematical function between LCL filter parameters and total harmonic distortion (THD) exists. This paper proposes an improved LCL filter design procedure for a grid-connected voltage-source inverter system. The THD of the current entering the utility grid for various LCL filter parameter combinations is generated through computational iterations. Using this data, the goal is to choose LCL filter parameters with less overall inductance value and lower manufacturing cost, while maintaining the same performance level compared to the conventional design procedure. The performance of the proposed procedure is verified by a case study, with simulation and experimental results, in which a 40 % reduction in overall inductance was achieved.

Presented in this paper is a comparative study of torque control of permanent magnet synchronous motors using two different controllers - the proportional-integral (PI) controller and proportional-resonant (PR) controller. Simulation results have been obtained using MATLAB/SIMULINK, while the hardware results have been obtained using a three-phase PMSM, three-phase inverter board and dSPACE DS1104. The simulation and hardware experimental results show the simplicity, robustness, and the same performance with small differences for each method.