A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

Abstract

This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability and grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD) is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine is proposed and a 2 MW wind turbine model is built to study the wind turbine fault ride-through capability. An integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to study its fault ride-through capability and the impact on the structural loads during grid three phase and two phase short circuit faults.

Design and Steady-State Performance of a Novel Winding Type Permanent Magnet Coupling with Slip Power Recovery Function

“…The schematic of the proposed WTPMC is illustrated in Figure 1. It is basically composed of three components: (1) an outer rotor that is embedded with three-phase windings and attached to the input shaft; (2) an inner rotor that is populated with permanent magnets and attached to the output shaft; (3) a slip power recovery circuit comprising a diode bridge rectifier, a boost converter based on insulated gate bipolar transistor (IGBT), an ultracapacitor, and an electronic control unit (ECU). Note that the outer and inner rotors are usually called the rotor assembly.…”

“…They can transmit torque through an air gap between two rotors that are, respectively, attached to the prime mover and the load. There are mainly three types of magnetic couplings, namely, electromagnetic coupling [1,2], permanent magnet synchronous coupling [3][4][5][6][7][8][9], and permanent magnet eddy current coupling [10][11][12][13][14][15][16]. These types of magnetic couplings have both axial-flux or radialflux configurations.…”

Technical impacts of high penetration levels of wind power on power system stability

“…Traditional system reinforcement (e.g., transformers, shunt capacitors, and line upgrades) may also be required to maintain adequate stability margins at higher levels of wind penetration. New wind turbine concepts, such as variable speed designs based on an electromagnetic coupler (synchronous generator directly connected to the grid, and able to generate reactive power up to three times rated) could also be considered …”

Improving Transient Stability in a Grid-Connected Squirrel-Cage Induction Generator Wind Turbine System Using a Fuzzy Logic Controller

“…In order to maintain voltage stability, after a short circuit fault, the rotor speed signal ω R controls the blade angle [36] to avoid the voltage instability related to over-speeding of the SCIG, as shown in Section 2 and in Figure 4. Since the rotor speed can vary in the range of a few percent, it may be useful to implement a fuzzy logic controller (FLC) for the blade angle control system to increase the sensitivity of the error signal 2 , as shown again in Figure 7 [26].…”