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Power management scheme for a converter system with multiple inputs and outputs is presented in the paper. The hybrid control approach was applied due to the required operation in various regimes. System collects the energy from multiple sources. The operation is supported by the battery.
A transformer based voltage sag generator to test renewable energy systems is presented. Design considerations concerning overvoltages and overcurrents during switching action are addressed. Measurement results of a 30 kW laboratory prototype testing a line side PWM converter and a DFIG are presented. Both measurement results for investigations on the transformer based sag generator at the line side...
The paper deals with power factor correction units suitable for implementation in uninterruptible power supplies. Several topologies of such correctors are described, analyzed and compared through simulation and experimentally. Special attention is paid to the efficiency of the correctors and to the possibility to build them utilizing unified power modules.
The presented research deals with a new configuration of a main traction converter with medium-frequency transformer which is intended for modern multisystem suburban units and locomotives. This paper exactly introduces proposed control of primary voltage source active rectifiers with direct control of trolley-wire current and active damping of low-frequency disturbances at the converter ac side....
This paper presents an enhanced direct power control (DPC) algorithm for doubly fed induction generators (DFIG) capable of reducing the common mode voltage (CMV). Nowadays the DFIG is often used in high power wind energy conversion systems (WECS). A common problem of converter fed induction machines are the bearing damages due to the bearing currents. The source of this problem is the common mode...
The paper analyses the control problem of the fixed speed wind energy conversion system based on the grid connected PMSG drive train and series converter located in its star point. It proposes unique approach to modeling of different types of sinusoidal PMSG in quasi-stationary operation. This provides basis for the development of the control algorithm whose primary function is active damping of the...
This paper describes design of protection and load-priority control devices for distributed generation. Possibilities of recent energy-metering integrated circuits are utilized in system diagnostics and protection. The experimental prototype is based on sensor modules and metering IC. Modules could be integrated with converters and distribution centres for voltage quality monitoring and equipment...
A major issue in grid connected PV-based renewable energy systems is the addition of new generators without energy production interruption, avoiding electrical architecture changes. In this work we propose a solution to this problem based on sliding mode control. We have tested our solution with some fuel-cells and a wind generator.
This paper presents a testing system for power converters control units. A hardware-in-the-loop test bench is designed for assessing control unit performances. A photovoltaic generator, coupled with a boost circuit, is software-simulated within a real-time environment, RT-Lab and coupled in closed loop with the physical control unit to be tested.
This paper deals a new strategy for wind-diesel hybrid system energy improvement using Ultracapacitors (UC) and Battery. Energy management strategies are focused on the frequencies distribution of the wind generator current between UC and Battery. The developed control laws are based on the knowledge of the dynamic behavior of each source, in aim to prevent the diesel generator against the fluctuating...
The paper describes the active power filter structure, control algorithms and methods for filter current regulation. Firstly, there is described the structure of parallel active filter power part, their resonant DC - link and structure of active filter general conception. Then there is described the control algorithms and methods for filter current regulation. The paper is mainly orientated to control...
The paper is devoted to the internal backup battery for an artificial heart. The main objectives are selection of the battery type, design of the DC-DC converter and performing required tests. The numerical model of the battery is used for analysis of the system. Results of measurements will be included.
This paper presents the design of two flat transformers in LLC resonant converter. The trend toward high power density, high efficiency, and low profile in power supplies has exposed a number of limitations in the use of magnetic component structures. In the LLC resonant converter, the switching loss is reduced by soft-switching. Therefore, LLC resonant converter can be operated at high switching...
The paper is concerned with the study of the speed control loop of an ultrahigh speed machine applied in the utilisation of renewables and in recovering waste energy. The rated speed of the machine is 90 000 rpm. The main target is to prevent the overspeed of the machine set by studying with simulation the response of the nonlinear speed control loop by taking into consideration both the mechanical...
The paper studies the performance of variable speed wind turbine (VSWT) configuration with non-inverting buck-boost converter. The wind turbine systems consist of permanent magnet synchronous generator (PMSG) connected to diode rectifier, DC chopper and load. New control strategy, based on the maximum power point tracking (MPPT) and limited power point tracking (LPPT) algorithms is used to improve...
Five, single-phase H-bridge converters are used to interface variable-speed, permanent magnet generator into a common DC bus. To draw high quality current from the generator and provide constant DC voltage, a modified implementation of the average current control technique is proposed. A phase shift circuit was added to the average current control to allow system operation at different load and speed...
This paper introduces a digitally performed voltage and current control mode for dc-dc step up converter based on FPGA technology. The voltage and current measurement was realized by using A/D converters as peripheral units of the FPGA system. Special attention was performed with current measurement and its A/D conversion due to the used predictive current mode algorithm which enables the fully digitalization...
In this paper a novel distributed photovoltaic power architecture using advanced lithium-ion batteries is proposed, which is mainly composed of a switched mode power converter and a power management system. This system exhibits the advantages of better protection and more efficient control on charge/discharge of the battery than the traditional photovoltaic power system. Furthermore, better use of...
Growing numbers of consumers distort AC networks with harmonics. Therefore suppression of the network pollution should be considered. This problem can be solved by using "network-friendly" converters. In this article some consumers are presented that pollute the single-phase AC networks with harmonics. Therefore the network voltage waveform will be distorted. In our study we examine the...
This paper presents a design procedure for a full-bridge converter with IGBT transistors loaded with serial resonant circuit. The main concern was the reduction of the switching losses in order to increase converter efficiency and power density. One of the basic applications of this topology with serial resonant load is with the induction heating converters. Theoretical analysis of the switching power...
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