No abstract

No abstract

No abstract

This paper investigates the application of the fuzzy logic power system stabilizer. Proposed stabilizer use estimated load angle of synchronous generator as the input. The load angle estimation is based on the real parameters of a synchronous generator, which are given by the corresponding voltage-current vector diagram. A fuzzy logic control scheme for synchronous generator stabilization is tested on the real laboratory model that includes digital system for excitation control (based on four DSPs) and synchronous generator connected to an AC system through transformer and two parallel transmission lines. The experiments were performed for step change of voltage reference. The behavior of the excitation system with fuzzy logic stabilizer is compared with excitation system based on the PI voltage controller and conventional power system stabilizer.

This paper describes the rotor flux estimation method for squirrel-cage induction generators (SCIGs) used in wind power applications. The proposed method estimates the rotor flux angle and magnitude in rotor reference frame by using measured stator currents, rotor angle and rotor time constant. The performance of the proposed method is compared to the performance of the voltage based estimator which is commonly used flux estimation method in sensorless field oriented vector control (FOC). The pure integrator in voltage based estimator is replaced by a low-pass filter with adaptive compensation and a phase locked loop (PLL) based position controller. Both methods are implemented in a digital control system and verified on the laboratory model. Experimental setup consists of a squirrel-cage induction machine (560 kW) connected to the grid via back-toback converter and a permanent magnet machine (375 kW) driven by the industrial frequency converter and used as a wind turbine emulator. The advantages and disadvantages of the proposed method are demonstrated by experiments. Keywords-rotor flux estimation; cage induction generator, wind power applications978-1-4799-7800-7/15/$31.00 ©2015 IEEE