Permanent Magnet Synchronous Generator Side Research Articles

Active-Control-Based Three-Phase Reclosing Scheme for Single Transmission Line With PMSGs

Electric devices may be damaged due to the strong secondary impact when the circuit breaker recloses on permanent faults, so it is significant to identify the fault nature to reduce the harm of grid faults. To achieve this point, a new control scheme is designed to make permanent magnet synchronous generator (PMSG) based wind turbines behave as a three-phase symmetrical voltage source, so the overcurrent can be detected for permanent faults when the circuit breaker on the PMSG side is reclosed, but only the tiny capacitance current is present for temporary faults. Therefore, the fault nature can be identified by detecting the current amplitude. To accurately extract the power-frequency phasors, a fast matrix pencil extraction method is adopted. This method solves the difficulty in fault nature detection caused by the rapid disappearance of current and voltage after a three-phase trip using the controllability of power electronics. Meanwhile, the severe secondary impact can be reduced since the injected current is small even for permanent faults. Additionally, the proposed method can ensure the fault current at the inverter terminal is within the limiting value and operate properly for remote high-resistance faults. Extensive simulations and experiments are performed to verify this method.

Control of PMSG wind electrical system in network context and during the MPP tracking process

This study presents a control strategy for grid-connected WES based on a permanent magnet synchronous generator (PMSG). The power system comprises five PMSG-based 2 MW which connected to the dc-bus with rectifiers, whereas the grid-side inverter is connected to the power grid throughout a grid-side filter. The objectives of grid-side inverter are to deliver the energy from the PMSGs side to the power grid, to regulate the dc-bus and to achieve unity power factor (UPF). The generator side converters are employed to control the velocities of the PMSGs with maximum power point tracking algorithm. Moreover, a pitch control algorithm is used. The proposed vector control technique (VCT) is able to fully decouple the quadrature (q) and direct (d) components of the currents. Simulations results using MATLAB/Simulink software are presented to validate the proposed control scheme for fault conditions into the grid as well as for normal working conditions.

Switched model based control of dual-PWM converters in the direct-drive permanent magnet synchronous wind turbine system

Nowadays, permanent magnet synchronous generator (PMSG) based direct drive wind power generation systems are developing rapidly and are attracting more and more attention. Dual-PWM (pulse width modulation) converters, as full power converters of the direct-drive wind power system, have excellent performance and have been widely used in recent years. The effective control of the back-to-back Dual-PWM converters plays an important role in generating the wind power efficiently. As the back-to-back Dual-PWM converters of the direct-drive wind power generation system can be considered as switched systems according to their working characteristics, this study presents one switched model based control strategy for the control of the Dual-PWM converters. First, the switched dynamic models of the converters on the PMSG side and the grid side are established, respectively. In contrast to the traditional averaged or linearized models, the proposed models can be more precise because no approximation will be introduced when the wind speed changes. Then, in order to realize the highest convergent rate, the min-projection strategy based switched control laws are derived. Furthermore, the stability analysis is done to assure the global stability of the proposed control strategy. Finally, detailed simulations and experiments are available to verify the proposed control method. The simulation and experimental results demonstrate that the proposed models and the control strategy are correct and effective. Comparing with the conventional proportional-integral control method, this paper integrates the back-to-back Dual-PWM converters as part of the proposed controller and utilizes the states of the converters as control variables, and thus, faster torque dynamics can be achieved.

Sensorless Control of PMSG Wind Turbine Using ANFIS

This paper deals with the control of permanent-magnet synchronous generator (PMSG) where the rotor position and speed estimation is essentially required to operate it on maximum power points. Here, Adaptive Neuro Fuzzy Inference System Technique (ANFIS) is used to estimate the speed and position of PMSG, where an ANFIS-system is continuously tuned with actual value of PMSG. The proposed system consists of a back-to-back converter, where PMSG side converter has MPPT output and another one is used for grid synchronization. The generator side ANFIS estimator is used to estimate the rotor position and speed accurately over a wide speed range. The purpose of grid side ANFIS estimator is to control and manage the inverter according to the load demand and storage of electricity in battery which is coupled with dc link of back to back converter respectively. The stored electricity in battery is fed back to grid when needed. The proposed system is designed in MATLAB/SIMULINK.

Harmonic Mitigation, Maximum Power Point Tracking, and Dynamic Performance of Variable-speed Grid-connected Wind Turbine

This article presents a method for harmonic mitigation and maximum power point tracking for a variable-speed grid-connected 20-kW wind turbine. The wind energy conversion system consists of a permanent magnet synchronous generator driven by variable-speed 20-kW wind turbine. The output of the permanent magnet synchronous generator is connected to a single-switch three-phase boost rectifier to generate DC voltage, which feeds a current-controlled inverter to interface the system with the electric utility. The single-switch three-phase boost rectifier is an active power factor correction technique to maintain the power factor at the permanent magnet synchronous generator side to nearly unity and mitigate the permanent magnet synchronous generator current harmonics. To mitigate inverter output current and voltage harmonics, an LCL filter has been used. A complete analysis of the harmonic content has been done everywhere in the system. The results show that the proposed maximum power point tracking control strategy succeeded to track the maximum wind power irrespective of the wind speed. This strategy in presence of an LCL filter achieved harmonic mitigation at the permanent magnet synchronous generator and inverter output sides. The dynamic response of the wind energy conversion system is tested under a three-phase fault condition. For comparison purposes, an active power filter is designed and checked against the single-switch three-phase boost rectifier for harmonic mitigation at the permanent magnet synchronous generator side.