Variable-speed Wind Turbine Generator System Research Articles

Stability Enhancement of DFIG Based Wind Turbine Under Three Phase Fault with STATCOM

The main aim of this paper is to improve the transient stability of Doubly Fed Induction Generator (DFIG) based wind turbine using Static Synchronous Compensator (STATCOM). In this paper, a multi-objective problem is formulated to minimize voltage deviations at the point of common coupling (PCC) and mitigate low frequency oscillations after clearing the faults. Genetic algorithm based STATCOM controller is used to enhance the stability of a grid-connected wind farm composed of a variable-speed wind turbine generator system (WTGS). The transient performance of the proposed control scheme is analyzed with a three-phase fault. The Simulations are carried out in MATLAB/Simulink environment.

Fault Ride-Through and Power Smoothing Control of PMSG-Based Wind Generation Using Supercapacitor Energy Storage System

This paper proposes an efficient power smoothing and fault ride-through control strategy for variable-speed grid-connected permanent magnet synchronous generator (PMSG)-based wind turbine generator (WTG) with supercapacitor energy storage system (SCESS). As WTG installations are increasing, these systems need to have a fault ride-through capability to stay alive during grid faults. As the wind speed is varying, power smoothing is needed as well. The controller proposed has twofold advantage for WTG equipped with SCESS. That is the SCESS is exploited to minimize the short-term fluctuation to have a smooth power profile during normal operation. In addition during grid side fault, the proposed controller stores the generated power from the WTG into the SCESS to ride-through the fault. Two back-to-back-connected three-level neutral-point-clamped (NPC) converters are used for the power conversion. The system model and the control strategy have been developed for the NPCs, the buck-boost converter and the variable-speed WTG system. The real time digital simulator (RTDS)-based results conducted on 2 MW/4 kV PMSG verify the effectiveness and superiority of the proposed controller.

Power Smoothing Control of PMSG Based Wind Generation Using Supercapacitor Energy Storage System

AbstractThis paper proposes an efficient power smoothing control strategy for variable speed grid connected permanent magnet synchronous generator (PMSG) based wind turbine generator (WTG) with supercapacitor energy storage system (SCESS). As WTG installations are increasing, these systems generate a fluctuated output power as a result of varying wind speed and need to have a power smoothing capability to have a smooth output power profile. The optimal size of the SCESS is determined and a controller is proposed and implemented to continuously charge and discharge the SCESS to achieve its objectives. The SCESS is exploited to minimize the short term fluctuation to have a smooth power profile during normal operation. A bi-directional buck boost converter is used to integrate the SCESS with the system. Two back to back connected three level Neutral Point Clamped (NPC) converters are used for the power conversion. The control strategy and the system model have been developed for the NPCs, the buck boost converter and the variable speed WTG system. The Real Time Digital Simulator (RTDS) based results conducted on 2 MW/4 kV PMSG verify the effectiveness and superiority of the proposed controller.

A Taguchi Approach for Optimum Design of Proportional-Integral Controllers in Cascaded Control Scheme

This study aims at resolving a specific problem in the area of renewable energy, energy storage systems, variable-speed drives, and flexible AC transmission system (FACTS) devices used in the electric power systems. The use of power conversion system (PCS) is very common in the aforementioned areas. A cascaded control scheme based on four proportional-integral (PI) controllers is widely used in the control of the PCS unit. Setting the parameters of the four cascaded PI controllers simultaneously is cumbersome, especially when the application is in the area of electrical power system which is difficult to express using a mathematical model or transfer function due to its nonlinear properties. This paper presents an optimum design procedure for the cascaded controller of the PCS unit using Taguchi method. To apply the design parameters obtained from Taguchi method, a renewable energy application is chosen where a variable-speed wind turbine generator system is connected to the power grid through two back-to-back PCS units. The effectiveness of the designed parameters using Taguchi method is then compared with that obtained using response surface methodology and genetic algorithm (RSM-GA) method under the grid fault condition.

Novel MPPT Control in Permanent Magnet Synchronous Generator System for Battery Energy Storage

This paper presents a novel sensorless maximum power point tracking (MPPT) control strategy for capturing the maximum energy from the fluctuating wind speed that being used in the stand-alone small scale variable speed wind turbine generator system (VSWTGS). The generated electricity from the wind turbine systems is used to charge battery energy storage. The whole system including the wind turbine, permanent magnet synchronous generator (PMSG), power converter, filter and lead acid battery has been simulated in Matlab/SimPowerSystem simulation software. The MPPT controller is developed to function as a wind speed estimator to generate an appropriate duty cycle for controlling power MOSFET switch in of the boost converter in order to capture maximum power in variable wind speed. From the simulation results, the power converters and filters are showing good performance in charging the lead acid battery. Besides, the novel MPPT controller is capable of extracting the maximum power from the fluctuating wind speed and exhibits good performance in both steady state and transient condition.

The operating characteristics of a mechanical governor for a variable-speed wind turbine generator.

This paper discribes the operating characteristics of a mechanical governor installed for blade pitch control, rotor speed control and generator power control in a variable-speed wind turbine generator system (VWTG). The VWTG is equipped with a 2-bladed teetered rotor of 15-meter in diameter and a 22-kW generator. Since the centrifugal forces of the weight-elements of the governor are utilized as direct control forces, the control are performed firmly and rapidly. The operation data show that the governor works satisfactorily to regulate rotor rotational speed and the generator power within the designed range of operation.