China
Africa
Explore chapters and articles related to this topic
Special Features of SimPowerSystems Models
Published in Viktor M. Perelmuter, Electrotechnical Systems, 2020
As it was said already, the circuits are provided in the model for the voltage limiting in the DC link. They consist of the series connected switch and resistor. For the switch model, the block Ideal Switch is used with the series diode (Braking chopper subsystem of the model). The control of the switch is carried out with a width-modulated signal: While DC link voltage Ubus is less than the rated value Ubusn, the switch is open; when Ubus>Ubusn the enabling pulses are given to the switch whose relative duration increases proportionate to the difference Ubus-Ubusn. One can consider the drive subsystem diagrams in more detail by carrying out commands Look Under Mask.
Power Electronics and Controls for Large Wind Turbines and Wind Farms
Published in Frede Blaabjerg, Dan M. Ionel, Renewable Energy Devices and Systems with Simulations in MATLAB® and ANSYS®, 2017
Ke Ma, Udai Shipurkar, Dan M. Ionel, Frede Blaabjerg
Generally, the power flow in and out of the system has to be managed carefully. The input mechanical power from the turbines should be limited by controlling the mechanical components such as pitch angle of rotors (θ) or direction of the yawing system. Meanwhile, the electrical power injected to the power grid should also be regulated according to the standards or commands given by the distribution system operator/transmission system operator (DSO/TSO). After the power flow in the system can be fully managed, more advanced features may be achieved by introducing extra control functions, such as the maximization of the generated power from turbines, ride-through operation of the grid faults, and supporting functions in both normal and abnormal operations of the power grid. In variable speed WTs, the current in the generator will typically be changed by controlling the generator-side converter, and thereby the rotational speed of the turbines can be adjusted to achieve maximum power production based on the available wind power. In respect to operation under grid fault, a coordinated control of several subsystems in the WT like the generator-/grid-side converters, braking chopper/crowbar, and pitch angle controller is necessary. Finally, the basic control functions of the electrical system like the current regulation, DC bus stabilization, and grid synchronization have to be quickly performed, where proportional–integral (PI) controllers or proportional-resonant controllers are typically used to track the reference.
Fault Ride-Through Capability of Variable-Speed Wind Generator Systems
Published in Mohd Hasan Ali, Wind Energy Systems, 2017
Variable-speed wind turbines using a PMSG equipped with full-scale back-to-back converters are very promising and suitable for application in large wind farms. Due to their full-scale power converter, they can deliver a larger amount of reactive power to the grid than a DFIG wind turbine under abnormal grid conditions. To achieve LVRT capability for wind turbine systems, a braking chopper method was reported, which is a relatively cheap solution with a simple control. However, it is hard to smooth the fluctuated power from the turbine, and the generated power is dissipated in the braking resistor.
Investigation of Transient Stability in Power System with Improved FRT Capable Solar PV Inverters
Published in Electric Power Components and Systems, 2023
C. Nithya, J. Preetha Roselyn, D. Devaraj
A coordinated-control strategy for PV converters and the static synchronous compensator is implemented in Ref. [5] to raise the LVRT capability of the PV system. This controller focuses on reactive power injection into the grid and fails to look into the overshoot at the ac side of the inverter during fault conditions. A Dynamic Voltage Restorer is proposed in Ref. [6] to improve the Fault Ride Through (FRT) capability of the PV system and its performance is compared with the other conventional FRT controllers. In Ref. [7], a DC braking chopper with Quasi Z source inverter is examined under fault conditions. This method keeps the voltage in the DC-link within 12% of the threshold value during grid disturbances. The voltage at PCC decreases, which activates the brake chopper to reduce the power dissipated in the resistor, which prevents the capacitor from overvoltage but this does not support in regulating the PCC voltage.
MPPT Based PMSG Wind Turbine System Using Sliding Model Control (SMC) and Artificial Neural Network (ANN) Based Regression Analysis
Published in IETE Journal of Research, 2022
Nirmal Kumar Agarwal, Pradip Kumar Sadhu, Suprava Chakraborty
The intermittent nature of wind energy gives rise to variable PMSG voltages due to which fluctuation occurs in the converters connected with the wind generation systems. In this paper, fault ride through topology has been implemented for PMSG using MATLAB simulink. In this study for variable speed, WECS drive for PWM converter is connected back to back for full power using PMSG for the improvement of system efficiency and also the 3-level NPC back-to-back converter PMSG wind turbine [2]. A suitable control strategy is developed to analyse the low-voltage ride through (LVRT) for fixed and variable speed wind turbine generator systems (WTGSs) so that it can be integrated with the flexible alternating current transmission system (FACTS) devices to increase the overall cost and minimize the voltage fluctuation of both fixed and variable speed WTGSs. Variable speed wind turbine (VSWT)-PMSG has the advantage that fixed and variable speed wind generators are connected in either series or parallel mode so that they can receive the reactive power during the disturbances (both symmetrical and unsymmetrical faults) in the power system network under harmonic instability [1]. This paper deals with variable speed wind generator driven-PMSG. The generator is connected with the PWM based frequency converter. This paper describes the operation and control of the maximum power and efficiency under different load conditions. In this paper, an efficient generator control has been proposed in a real-time application (dSPACE) to achieve the optimum generator d-axis current component that is imposed by the power converter for only studies of PMSG for rotor flux [3]. In this paper, the proposed wind turbine model of variable speed doubly fed induction generator and variable speed permanent magnet synchronous generator have been simulated to optimize wind energy to become increasingly competitive with conventional energy sources [4]. LVRT of multi-pole permanent magnet synchronous generator (PMSG) for wind turbine systems is proposed to reduce the energy storage system (ESS) and system performance. In this regard, a control strategy for ESS and braking chopper (BS) is used. The result of the control strategy of ESS has been verified and made the system cost effective for high-speed online set control of PMSG [5]. A prototype variable-speed sensorless PD controller WECS control strategy of 20 KW PMSG is used for maximum power estimate in order to capture the amount of energy injected in the grid-connected systems with the variable wind speed by controlling the modulation index of PWM inverter. MATLAB simulink is proposed for different system characteristics with the dynamic behaviour of different control concepts [6].