Alvis Sokolovs

Drive selection for electric kart

In this paper the parameters for choosing an electric drive for an electric kart have been analyzed. The advantages and disadvantages of different electric drive configurations have been shown while focusing on development of academic research prototype for future use in student education.

Closed current loop regulator for electric kart DC motor torque stabilization

PID regulator has been adapted to control DC motor current of an electric cart. Both simulation and experiments were carried out to evaluate controller operation during step-change of control signal. The aim is to stabilize motor torque and monitor motor current to protect power converter from dangerous current overshoots.

Front-end converter choice considerations for PMSG-based micro-wind turbines

In this paper authors investigated how output power capability of two different micro-wind energy systems with permanent magnet synchronous generators depends on choice of front-end converter. Two converter topologies were considered: passive diode bridge rectifier and active rectifier. A comparison of output power and generated energy potential is given and analyzed for desired location.

Solar tracker supervisory system

Most of the solar trackers do not have any feedback of their position, so the only possibility to check real position is visual inspection. This paper describes a device that can be used to supervise solar trackers and in the case of faulty operations it sends alarm. The main task was to develop the device easy in implementation. The device implementation does not assume a rebuilding of solar tracker construction. It has to be stuck to back side of photovoltaic panel. An accelerometer in couple with magnetometer is used to measure real position of panel, and microcontroller checks the correctness of the position.

An Induction Motor Based Wind Turbine Emulator

Abstract The authors present a small-scale wind turbine emulator based on the AC drive system and discuss the methods for power coefficient calculation. In the work, the experimental set-up consisting of an AC induction motor, a frequency converter, a synchronous permanent magnet generator, a DC-DC boost converter and DC load was simulated and tested using real-life equipment. The experimentally obtained wind turbine power and torque diagrams using the emulator are in a good agreement with the theoretical ones. Kopsavilkums Šajā rakstā parādīta mazas jaudas vēja turbīnas emulatora izveide ar maiņstrāvas piedziņas sistēmu, kā arī analizētas vairākas turbīnas jaudas koeficienta analītiskās aprēķina metodes. Vēja turbīnas emulatora eksperimentālais stends, kas sastāv no asinhronā elektromotora, frekvenču pārveidotāja, sinhronā pastāvīgo magnētu ģeneratora, līdzstrāvas paaugstinošā pārveidotāja un slodzes, tika pārbaudīts gan simulēšanas vidē, gan uz reālām iekārtām. Eksperimentāli iegūtās vēja turbīnas emulatora jaudas un momenta diagrammas ir salīdzinātas ar teorētiskajām.

Matrix Converter Bi-directional Switch Power Loss and Cooling Condition Estimation for Integrated Drives

Matrix Converter Bi-directional Switch Power Loss and Cooling Condition Estimation for Integrated Drives In this paper power loss estimation of bi-directional switch of matrix converter is done by means of calculation and experiments. For safe operation of power devices an efficient cooling system of specific device must be designed. This work is part of a greater project of integrated matrix converter AC drives and the cooling problem here is viewed in context of this task. It is necessary to develop a compact power board and cooling system to extract excessive heat from power devices.

Development of a Modular Power Converter

Development of a Modular Power Converter This report describes the most important details of elaboration of a versatile power module that can be utilized as a part of various converters. Two or more modules connected together can form a frequency converter or multilevel converter or 3-phase inverter/rectifier etc. Initially the module was developed for fast prototyping of uninterruptible power supplies and energy systems with alternative energy sources. The module can be used also as a basis for laboratory equipment of the power electronics course.

Cost and space effective IGBT gate drive circuit for bi-directional switch of matrix converter

This paper seeks a simple, cost effective and compact gate drive circuit for bi-directional switch of matrix converter. Principals of IGBT commutation and bi-directional switch commutation in matrix converters are reviewed. Three simple IGBT gate drive circuits are presented and simulated in PSpice and simulation results are approved by experiments in the end of this paper. Paper concludes with comparative numbers of gate drive costs.

Power capability and efficiency comparison of direct drive PMSG at different power control strategies

The authors present the results of experimental work on a small-power direct driven permanent magnet synchronous generator reactive power compensation comparison with two methods. Particular generator is targeted for small size wind power systems, and is tested on a wind turbine emulator that consists of an AC induction motor, a frequency converter and a torque feedback. Generator output power was measured with three different setups: AC-DC converter and a DC-DC boost converter; capacitor compensated AC-DC converter and a DC-DC boost converter; frequency converter with field oriented control of synchronous generators. Simulation and experimental results of generator output power and efficiency are obtained and analyzed at different generator speed values.

Possible design of bus bar construction for matrix converter

This paper explains use of bus bars in matrix converts, different layouts and shapes of possible construction are considered. In this paper the most acceptable and cost effective version of layout of bus bars and topology of matrix converter is quested for more detailed analysis in future.