Danvu Nguyen

Implementation of module-based wind power system with pitch angle control

AbstractThis paper presents a module approach for lab-scale wind power systems (WPS). The system is designed into functional modules. These modules can be used independently or in other projects. It is also convenient to handle and set up them on a small table in classrooms and labs. Hence, they are very useful for training and research. In addition, operation on both aerodynamic side and generator side is developed in this research. Many papers on wind system simulators focus only on aerodynamic system with pitch angle control or generator system with optimal control. Thus, the operation of WPS in 2 regions, which requires coordination of aerodynamic and generator sides, is not explained and demonstrated in previous study. Many case studies are conducted to demonstrate the capability of the module-based WPS. The system is capable of speed control, optimal power control and pitch angle control. As illustrated in experimental results, these control strategies can efficiently cooperate under operation in 2 ...

Dynamic response evaluation of sensorless MPPT method for hybrid PV-DFIG wind turbine system

AbstractThis research proposes a sensorless Maximum Power Point Tracking (MPPT) method for a hybrid Photovoltaic-Wind system, which consists of Photovoltaic (PV) system and Doubly-Fed Induction Generator (DFIG) Wind Turbine. In the hybrid system, the DC/DC converter output of the PV system is directly connected to the DC-link of DFIG’s back-to-back converter. Therefore, the PV inverter and its associated circuit can be removed in this structure. Typically, the PV power is monitored by using PV current sensor and PV voltage sensor for MPPT. In this paper, the powers of converters on grid side and rotor side of DFIG are used to estimate the PV power without the PV current sensor. That can efficiently reduce the cost of the hybrid system. The detailed analysis of the sensorless MPPT method, which includes derived equations and operation response, is also presented in this paper. In addition, an overview of PV-DFIG research in literature is stated to supply comprehensive knowledge of related research.

Optimal power control of DFIG wind turbines using a simplified power converter

Traditionally, a back-to-back power converter, which includes a grid side converter (GSC) and a rotor side converter (RSC), is employed to regulate the output power of Doubly Fed Induction Generator (DFIG) wind turbines (WTs). Therefore, two controllers are required for power regulation of DFIG. This paper proposes a strategy to control the DFIG with a simplified power converter. This converter consists of only a RSC and a passive rectifier which is simpler and cheaper than the GSC. In addition, the proposed strategy, which is referred to as self-compensating DFIG strategy in this research, can control the DFIG to generate the optimal power and to compensate distorted currents which injected by the simplified power converter to the grid. Extensive simulation studies are conducted to investigate the performance of the proposed system. Moreover, the capability of maximum power control of the system is examined using practical wind speed data. As demonstrated in the simulation results, the proposed system can be a cost-effective alternative of a conventional system to generate the maximum power.

Analysis of self-compensating DFIG for wind energy conversion systems

In order to decrease the cost of Doubly Fed Induction Generator (DFIG)-based wind energy conversion system (WECS), this research offers a self-compensating method for DFIG. The grid-side converter (GSC) in the conventional DFIG configuration is replaced by the passive rectifier which is simpler and cheaper. The instantaneous power theory is applied to monitor the high-order harmonic currents of the rectifier. Afterwards, the DFIG is controlled to compensate these components and guarantee the power quality of the grid without the GSC. Therefore, this method can reduce the cost of not only the GSC but also many associated circuits, such as protection circuits, sensors and so on. Extensive simulation studies are carried out to examine the feasibility and performance of the self-compensating DFIG for wind energy conversion systems. Several operating scenarios and comparisons are conducted and analyzed for the proposed method. As seen in the simulation results, the proposed system can promisingly become an alternative of the conventional system.

Control of DFIG with new space-vector based hysteresis current regulator title

In this paper, the novel nonlinear current controller in dq reference frame is presented to replace the traditional Proportional-Integral (PI) regulator in the conventional control scheme of Doubly Fed Induction Generators (DFIGs). The proposed method is based on a new hysteresis current controller, which can modulate the voltage space vector directly in the dq rotation frame. Therefore, it is easy to employ the new method in the vector-oriented-control scheme of DFIG. The feasibility and performance of the proposed method are examined by using Matlab/Simulink. The simulation results demonstrate the very fast transient response and the ride through capability of this method under voltage dips.