Wlodzimierz Koczara

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The power generation system with a doubly fed induction generator (DFIG), which can be used as an autonomous power system after the loss of mains in a distributed generation network, is described. After the mains outage, a fixed frequency and an amplitude of the output voltage are obtained, despite the variable rotor speed. For this reason, it can be(More)
A control method for stand alone mode operation of doubly fed induction generator is presented. The method bases on the stator voltage vector control represented in the synchronously rotated polar coordinates. The generated stator voltage is controlled by rotor currents. Amplitude of stator voltage and its frequency are controlled independently. The output(More)
The paper describes a new holistic approach to the modeling of integrated renewable energy systems. The method is using the DK5 modeling/design environment from Celoxica and is based on the new Handel-C programming language. The goal of the work carried out was to achieve a combined model of a photovoltaic energy system and a wind power system, which would(More)
The following paper presents bidirectional switch neutral point clamped three-level inverter topology, which is intended for low voltage applications. The inverter schematic and its principles of operation are presented. Then conduction and switching losses model derivation is proposed. According to obtained model equations, proposed concept is compared(More)
The paper presents variable speed generation system producing standardised 400 V/230 V/50 Hz voltage. An internal combustion engine (diesel engine) is driving a permanent magnet axial flux generator. An AC/AC power electronic system converts variable frequency and amplitude the permanent magnet generator AC voltage to the standardised AC voltage. The axial(More)
The following paper presents the method of poles position identification of the axial flux permanent magnet machine at zero and low speed. The identification is used for starting the motor in the demanded direction. The axial flux motor possesses a large number of poles which results in a small mechanical angle for magnet sector. The derived poles position(More)
We show that frequency bands of interaction as well as dynamics of energy flow to the point of common coupling (PCC) lead to hybrid system design keys. Related to each power source and storage device, segmentation of frequency domain of the hybrid system is achieved by control strategy in time domain.
This paper presents a novel method for parallel operation of adjustable speed power-electronic generation systems. The proposed method is based on the well known droop scheme and therefore does not require any additional interconnections between units operating in parallel. Modifications and extensions to the conventional droop scheme are introduced to(More)
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