Martina Kutija

University of Zagreb, Faculty of Electrical Engineering and Computing (FER) · Department of Electric Machines, Drives and Automation

This paper analyses the harmonic emissions of industrial voltage-source-inverter (VSI)-fed adjustable speed drives with a three-phase diode bridge rectifier. Line current distortions of industrial VSI-fed drives with and without a DC choke are compared under varying load. Experimental tests are conducted on three different laboratory test rigs unde...

This paper presents a new rotor flux estimation method for sensorless vector controlled squirrel-cage induction generators used in wind power applications. The proposed method is based on a phase-locked loop (PLL) and the orthogonality between the rotor flux space vector and its back electromotive force (EMF) space vector. Rotor flux is estimated u...

This paper presents a nonlinear power system stabilizer based on a pointwise min-norm control law and a third order state space mathematical model of the synchronous generator connected through transmission lines to the power system. Commonly, the mathematical model includes transient electromotive force as a state variable that cannot be measured....

Permanent magnet synchronous generators have wide application in wind energy conversion systems. If interior permanent magnet synchronous generator (IPMSG) is connected to the grid by a full scale AC-DC-AC converter, the wind turbine can be operated to extract maximum wind power at different wind speeds by optimally adjusting shaft speed. In this p...

In this paper maximum torque per ampere and loss minimization control methods for an interior permanent magnet synchronous generator are compared. Permanent magnet synchronous generators have wide application in wind energy conversion systems due to high efficiency, high power density, high power factor and wide speed operating range. Maximum torqu...

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 paper proposes a new method for magnetizing speed sensorless squirrel-cage induction generators used in wind power applications. These generators are magnetized at non-zero speeds, and for this reason, their successful magnetization is difficult to achieve. If the generator speed is not known, the required converter output frequency is also unk...

This paper describes a current limiting technique for V/f controlled induction machines. In V/f control method stator current is not directly controlled so the implementation of current limiter is a challenging task. The current limiter proposed in this paper is composed of a programmable ramp and two proportional-integral (PI) controllers which ke...

This paper compares two methods for rotor flux estimation of sensorless vector controlled squirrel-cage induction machine used in wind power applications. The compared methods are based on the integration of stator back electromotive force (back-emf) which is obtained from the machine parameters and measured voltages and currents. Rotor flux estima...