ISSN 1805-3386

April 6, 2020


2015 No.4

Review of Selected Multi-Element Resonant Topologies

Koscelnik, J., Mazgut, R., Kascak, S., Prazenica, M.

The paper deals with an analysis and comparison of multi-element resonant topologies. The superior performance of the investigated converters provides inherent current protection and very low circulating energy. The converter consists of two resonant tanks and HF transformer in case of the LCTLC topology. The paper shows the design of the resonant elements. The converters can achieve zero current switching (ZCS) and zero voltage switching (ZVS) conditions for the primary and secondary-side of the device respectively. The converters achieve high values of power density and efficiency up to 96 % at the full load. The paper includes the basic equations, analysis and simulation of the chosen topologies (LCTLC, LCLCL, LCL2C2).


Keywords: Multi-element resonant converter, review of the resonant converters, switching conditions, LCTLC, LCLCL, LCL2C2.


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Sensorless Field Oriented Control of BLDC Motors for MAVs

Rau, D., Rodina, J., Palkovič, L., Hubinský, P.

To achieve longer flight duration of the micro aerial vehicles (MAVs) it is needed to optimize their propulsion system. A typical propulsion system of VTOL (vertical take-off and landing) MAV consist of the propeller BLDC (brushless DC) motor, motor controller and battery (typically Lithium based chemistry). All these parts of the propulsion system can be optimized in a specific way. In the case of the propeller, this can be done by the optimization of static and dynamic thrust performance. The motor construction can be optimized by using lighter materials or stronger rotor magnets. As for the battery - alternative power sources like solar panels, hydrogen fuel cells etc. may be used. We are focusing on the optimization of the motor control part. In this paper, we are presenting synthesis of the BLDC controller using the field oriented control strategy which promises better performance in the dynamical response of the propulsion system, lower power consumption and generally higher efficiency in comparison with the traditional six step commutation techniques.


Keywords: MAV, BLDC, FOC, vector control, observer.


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Control System of Battery Storage to Eliminate the Power Variation According to the Electricity Prediction

Liška, M., Beláň, A., Cerman, A., Janík, M.

Rapid variations of the output power from photovoltaic power plants can have some significant side effects on the quality of electricity, such as the voltage variation, switching of tap changers, etc. In the other case, these variations also make the difference between the prediction and real electricity production. Generally, the goal of the accumulation of electricity is to charge the storage element in surplus of electricity and discharge when the energy is insufficient. In this paper, the accumulation of electricity in a photovoltaic power plant is not used for this purpose, but to charge and discharge the storage element with respect to the prediction of electricity.


Keywords: Photovoltaic power plant, power variation, battery controller, electricity prediction.


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Conceptual Design of Electromechanical Systems Using Ferrofluids

Polcar, P., Český, J.

This paper presents an overview of a new conceptual design of electromechanical systems using ferromagnetic liquids. Idea of the new concept is explained, advantages and disadvantages of such systems are discussed and three illustrative examples are presented. Numerical simulations and experiments on real devices are employed to study properties of these systems.


Keywords: Air gap, ferrofluid, ferromagnetic liquids, electromechanical systems, magnetic forces, static characteristics, dynamic characteristics, numerical simulation, experimental verification.


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Sensorless Control of Two-Phase Induction Machine using MRAS Techniques

Kascak, S., Mazgut, R.

The paper presents most commonly used control techniques based on the Model Reference Adaptive System (MRAS) for the Two-Phase Induction Machine (TPIM). The theoretical and experimental results are obtained using the Rotor Flux, Back EMF, and Reactive power estimators. The main characteristic of this research is their performance during start-up and reverse conditions. The experimental results were obtained at the no load operation. The estimated values of the angular speed are compared with the data from the incremental encoder. The Matlab/Simulink simulation software was utilized to perform the simulation results. The control techniques implementation and data acquisition were done by the technical computing device Dspace DS1103.


Keywords: Model Reference Adaptive System, Two-Phase Induction Machine, Speed estimation


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