The Loss of Self-Excitation Capability in Stand-Alone Synchronous Reluctance Generators
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
Authors: Ibrahim, Maged; Pillay, Pragasen
Abstract
This paper analyzes the capability of synchronous reluctance generators (SynRGs) to achieve successful self-excitation when operating in stand-alone systems. To initiate the self-excitation process, the machine steel core has to retain sufficient residual flux during the generator startup. This residual flux depends on the magnetic properties of the machine core as well as the previous machine operating condition. A hysteresis model is developed to simulate the flux linkage-current characteristics of the SynRG for different operating conditions. The model then calculates the machine residual flux linkage after each operation, which indicates the machine capability for self-excitation during the next startup. The simulation results show that the rotor steel core of the synchronous reluctance machine (SynRM) can be demagnetized when the generator is subjected to a short-circuit condition or when the generator shaft is subjected to abrupt deceleration. These simulation results are also validated by experimental measurements on a 5 hp SynRM.
Standalone and Grid Connected Operations of a SynRG based WECS with BESS
2018 IEEMA ENGINEER INFINITE CONFERENCE (ETECHNXT)
Authors: Vijay, Deepu M.; Singh, Bhim; Bhuvaneswari, G.
Abstract
This work advocates an effective way of energy management in a microgrid consisting of a synchronous reluctance generator (SynRG) based wind energy conversion system (WECS) connected to a DC bus, which voltage is maintained by a battery energy storage system (BESS). The system is capable of feeding a fairly constant value of power to the grid apart from supplying the local loads. Apart from maintaining the DC link voltage, the BESS compensates for the fluctuations in the wind power by channelizing the power in and out of the BESS as per the power generation and power demand. The SynRG is operated in direct torque control (DTC) mode corresponding to maximum power point (MPP) of the WECS by adjusting the control inputs to the machine side converter. The battery in BESS, is integrated to the DC bus using a bidirectional converter (BDC), which helps in charging and discharging of the battery. A voltage source converter (VSC) connected on the grid side evacuates the power from the common DC link and feeds it to the three-phase grid. This VSC is controlled in such a way as to maintain the required power factor on the grid side as per the reference values of the direct and quadrature axes components of currents specified. The proposed system is designed, modeled and simulated in Simulink/ MATLAB environment.