Variable Speed Constant Frequency Operation Research Articles

The Technical to Realize Variable Speed Constant Frequency Operation of Large Wind Turbine Generator

In this paper, through the introduction of the existing various mainstream wind turbine model, understand all kinds of operation mode and control method of wind turbines, contrast to put forward all kinds of wind turbine operation mode and control methods of the advantages and disadvantages, comprehensive put forward more effective technology of large wind turbines to realize variable speed constant frequency operation method, as well as for large wind turbines to realize variable speed constant frequency technology methods of the future.

Design and Optimization of Electric Continuous Variable Transmission System for Wind Power Generation

A novel brushless electric continuous variable transmission (E-CVT) system is presented and optimized. The proposed system offers an alternative solution for a variable-speed constant-frequency operation of the wind turbine application. The key is to eliminate the gearbox and brushes in the machine and this E-CVT system comprises of two rotors and two stators within one machine. This design inherits and integrates the merits of the direct-drive permanent magnet generator and the doubly fed induction generator with the additional benefit of the improved torque density and the need for a low-cost partial-scale converter. The structure, operation principle, and performance are analyzed. Genetic algorithm is employed to optimize the parameters for maximizing its power density. Time-stepping finite-element method is used to analyze the dynamic performance of the proposed system.

Performance Study of Brushless Doubly-Fed Machines in Variable Speed Constant Frequency Wind Power Generation

The brushless doubly-fed machine (BDFM) is a new type of induction machine with good application in wind power generation. In this paper, the design method for the stator winding and rotor winding of BDFM in detail on the basis of operation principle of the machine is introduced. As an example, The performance simulation for a 480kW cage rotor BDFM with 8-pole stator power winding and 4-pole control winding can be considered under the condition of no-load, rated load and variable speed constant frequency operation based on field-circuit coupled finite element analysis. Simulation results show that the design method has good performance and is feasible in variable speed constant frequency wind generation systems.

Passivity-based control for variable speed constant frequency operation of a DFIG wind turbine

A standard passivity based control for a double fed induction generator of a wind turbine is presented. The control problem is posed as a variable speed constant frequency operation with the aim to maximise the generated electric power. The controller is designed in such a way that the dual control objective, unity power factor in the stator side and speed tracking in the mechanical port, are satisfied guaranteeing internal stability. The proposed scheme is the first attempt to approach the speed tracking operation from the energy dissipation (passivity) perspective. Simulation results show good performance of the control scheme for wind speeds in different operating regimes.

Rotor Side Control of Wells Turbine Driven Variable Speed Constant Frequency Induction Generator

Wave energy can meet a sizeable portion of the world's energy needs. For countries having long coastlines, wave energy conversion is an attractive proposition. Wells turbine driven grid–connected systems with squirrel cage induction generators have been in existence; however, rotor–side control of grid–connected induction machine is an attractive option for variable speed constant frequency operation. The power rating of the converter can be considerably reduced when used in the rotor circuit over a limited slip range (approximately 50%). Since the stator is directly connected to the grid, the stator flux is constant over the entire operating region. Therefore, the torque can be maintained at its rated value even above synchronous speed. This article describes the simulation of a rotor side chopper controller for wave energy.