Marwan Rosyadi

Transient stability enhancement of variable speed permanent magnet wind generator using adaptive PI-Fuzzy controller

This paper proposes an application of adaptive PI-Fuzzy controller for back to back converter of variable speed permanent magnet wind generator in order to enhance transient stability of wind farms including induction generators. The back to back converter control scheme is developed based on the field orientation control, in which both active and reactive power delivered to a power grid system are controlled effectively. The adaptive PI-Fuzzy controller is proposed to enhance performances of the variable speed permanent magnet wind generator in various operating conditions. To evaluate the controller system capabilities, simulation analyses are performed on a model system composed of a wind farm connected to an infinite bus. The simulations have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is more effective to enhance the transient stability of wind farm during severe network disturbance compared with that with conventional PI controller.

Low voltage ride-through capability improvement of wind farms using variable speed permanent magnet wind generator

In this paper, low voltage ride-through (LVRT) capability improvement of wind turbine generator system is investigated, in which two wind farms model connected with multi-machine power system is considered. The wind farms considered consist of fixed speed wind turbine based induction generator and variable speed wind turbine with permanent magnet synchronous generator. A new control scheme is developed for back-to-back converters of PMSG with DC link protection controller embedded to support fixed speed wind generators during fault condition. Simulation results by PSCAD/EMTDC show that the proposed control scheme is very effective to improve the LVRT of wind farm during severe network disturbance.

Fuzzy-PI controller design for PM wind generator to improve Fault Ride Through of wind farm

In this paper, application of Fuzzy-PI control for the voltage source converter based permanent magnet synchronous wind generator is proposed in order to improve Fault Ride Through (FRT) capability of wind farm including fixed speed induction generators. The membership of fuzzy logic controller is designed based on the bode diagram analysis to achieve a good stability performance of the controller system in normal and fault conditions. To evaluate the controller system capabilities, simulation analyses are performed on a model system composed of two wind farms connected to an infinite bus. Simulation results by PSCAD/EMTDC show that the proposed controller is very effective to improve the FRT of wind farm during fault in the grid system.

Dynamic analysis of offshore wind farm with PM wind generators using simplified model

In this paper dynamic behavior analysis of offshore wind farm with permanent magnet wind generators is performed. A simplified model of the permanent magnet synchronous generator is proposed to implement in PSCAD/ EMTDC in order to reduce the complexity of the analysis of a large offshore wind farm and the long simulation time. The performance of simplified model is validated in the comparative analysis with the detailed model. The simulation analysis has been performed for the condition under randomly fluctuating wind speed and severe network disturbance.

Tie line power control of HVDC transmission to damp frequency fluctuation of power system with large scale wind farm integrated

In this paper, effect of tie line power control of two area power system connected through VSC-HVDC line on damping load frequency deviation is investigated. New control scheme of the VSC-HVDC to provide frequency regulation is proposed. The control strategy is useful for connecting a power system with high penetration of wind farm to other power system. The study has been performed by simulation analysis using PSCAD/EMTDC, and the dynamic performance of the VSC-HVDC with the proposed control is demonstrated. Simulation results shows that proposed controller can damp frequency fluctuation effectively.

Development of phasor type model of PMSG based wind farm for dynamic simulation analysis

This paper presents a phasor type model of variable speed wind turbine with Permanent Magnet Synchronous Generator (PMSG) for dynamic simulation study on Matlab/Simulink. Aim of the phasor model is to diminish the complexity and simulation time of the analysis of grid connected wind farm. The proposed phasor type model can be used as aggregated and individual model representations for the wind generators. Comparative analysis between the proposed phasor type model and instantaneous value based detailed model on PSCAD/EMTDC is performed to demonstrate the accuracy of the proposed model. The simulation results show that the proposed phasor model has sufficient accuracy for analyzing dynamic characteristics.

Sensorless virtual resistance damping method for grid-connected three-phase PWM converter with LCL filter

Three-phase PWM converter is commonly connected to utility grid through L or LCL filter to remove grid current harmonic components. LCL filter has many advantages compared with L filter. However, resonance at high frequency caused by the LCL filter may lead stability problem. Passive damping method (PD) or active damping method (AD) is used to solve this problem. PD brings the additional loss due to damping resistor. On the other hand, virtual resistance damping method of AD, in general, needs additional sensor. Therefore, this paper proposes sensorless virtual resistance damping method for grid-connected three-phase PWM converter with LCL filter.

A new pitch control system of wind turbine to damp power system frequency fluctuations

In this paper a new controller of pitch angle control system for fixed speed wind turbines based wind farm is proposed to smooth output power for damping frequency fluctuation of power system. The control system is designed in such way for the pitch controller to operate based on wind speed and load frequency deviation information. The wind farm is connected to a multi machine power system which is composed of 4 synchronous generators and a static load. Simulation analyses have been carried out to investigate the performance of the controller using real wind speed data. It is shown that the output power from the wind farm can be controlled smoothly damping the load frequency fluctuation effectively.

Simplified model of HVDC transmission system connecting offshore wind farm to onshore grid

This paper presents a simplified model of Voltage Source Converter based High Voltage DC (VSC-HVDC) transmission system for dynamic simulation study. Aim of the simplified model is to diminish the complexity and simulation time of the analysis of grid integrated offshore Wind Farm (WF) connected through VSC-HVDC transmission line. This is because simulation analysis of offshore WF based on the detailed VSC-HVDC model needs very large computing time. To evaluate performance of the derived simplified model of VSC-HVDC, simulation analysis is performed on a multi-machine power system model composed of Variable Speed Wind Turbines (VSWTs)-Permanent Magnet Synchronous Generators (PMSGs), VSC-HVDC, and Synchronous Generators (SGs). Comparative analysis between the proposed simplified model and the detailed model of VSC-HVDC is also performed and presented. The simulation results show that the proposed simplified model of VSC-HVDC has sufficient accuracy for analyzing dynamic characteristics.

Cooperated stabilizing control of PMSG based grid connected wind farm

This paper proposes a control system design for cooperated stabilizing control of PMSG based grid connected wind farm. In this study, a wind farm composed of PMSGs and SCIGs is considered to be connected to multi-machine power system. Though outputs of the SCIG based wind turbines are collected on AC network, PMSG based wind turbines are integrated in DC network with single grid side converter. In order to contribute to frequency and voltage stabilizing control, controller system of the inverter is modified in order for its active and reactive powers to be delivered to the grid easily and effectively. Simulation analysis is performed by using PSCAD/EMTDC, in which comparative analysis between proposed control strategy and conventional strategy is performed.