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The need for efficient, smaller, lighter and cheaper power supply units drive the investigation of using high switching frequency soft switching resonant converters. This work presents an 88% efficient 48V nominal input converter switching at 6 MHz and output power of 21 Watts achieving power density of 7 W/cm3 for Power-over-Ethernet LED lighting applications. The switching frequency is used to control...
One of the important role for dc-dc converters is to regulate output voltage against the transient variation of input voltage. Recently, renewable energy becomes popular and renewable power generators are connected to the dc power grid directly, dc bus voltage is affected from them. Therefore, the improvement of the transient response against the variation of the dc bus voltage is required to control...
For reducing the inconsistent state of charges (SOCs) of lithium-ion battery cells and making the full use of battery packs, effective battery balancing technology should be in place for battery management systems. Since aged battery packs usually suffer from not only non-uniform cell SOCs and voltages but also non-uniform cell capacities, it is more challenging to balance an aged battery pack than...
Interior permanent magnet synchronous motors (IPMSMs) are used in various applications. Because of concerns about environmental problems such as global warming, IPMSMs are investigated to improve the efficiency to save energy. Magnetic steel sheets are commonly used in IPMSMs, and the use of low-iron-loss materials in IPMSMs to improve their performance has recently been examined. In this study, the...
The paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback...
This paper describes fuzzy cooperative coevolution adaptive control which uses a common genetic algorithm to obtain the coefficients of the adaptive fuzzy regulator. The plant under consideration is multi-mass drive system with elastic couplings. A comparison between systems with fuzzy control and conventional PID-control is considered. It is shown that fuzzy method allows to suppress torsional vibrations...
The following paper presents new fault tolerant converter topology for switched reluctance machines, that features multilevel output along with its advantages. The principle of operation in normal as well as in the fault conditions are described. Previously proposed modulation strategy including DC bus voltage balancing scheme is applied and tested in measurements. Low cost, discrete implementation...
This paper discusses the challenges of paralleling dual modules with special focus on the currently introduced dual modules like LinPak, nHPD2, XHP, LV/HV100, etc. Compared with IHM/IHV Modules 3 to 4 times as many modules have to be paralleled to achieve the same output power. Therefore the parallel connection will play a major role in designing high power converters, used e.g. in traction applications...
This article is going to describe the design and implementation of a non-inverting buck-boost converter for lithium-ion battery chargers. The described modulation strategy allows to achieve a high efficiency and high power density converter. The prototype is made up of off-the-shelf components and the elaborated current predictive control algorithm avoids the use of a current sensor. Only voltage...
A novel battery energy storage system (BESS) based on an enhanced modular multilevel converter (M2C) with the ability to switch its modules in parallel is being presented. Compared to a full-bridge M2C equipped with batteries as energy storage elements on its submodules, the losses are reduced by 20%. The raise in efficiency is thoroughly explained as well as its reliability. Its high efficiency,...
The paper addresses the problem of fault detection in an unbalanced microgrid with distributed generators, using algorithms based on harmonic estimation: Wavelet Transform (WT), Fast Fourier Transform (FFT) and Reduced Fast Fourier Transform (RFFT). Simulations were carried out in the MATLAB/SimPowerSystems environment. Modified IEEE13 bus system with distributed generation was used. Experimental...
The article deals with power density analysis for machine tool multi-machine system power converter through the definition of recuperated energy returned to the DC link. Recuperated energy absorption in different operation modes was shown. Power density improvement is shown in case of active voltage rectifier implementation.
This work investigates the possibility to reduce the thermal stressing of high power IGBT modules in a DC-current application. Using four load current profiles as examples, two mitigation strategies are presented and their benefit to the power stack in terms of lifetime prolongation is evaluated. In the final part of the work, the investigation focuses on the relation between the shape of the load...
The ultra-low gate charge characteristics and low gate voltage limitation of a GaN enhancement mode HEMT in combination with stray circuit elements poses many challenges of driving them in power electronic applications. This paper investigates the effect of changing gate resistances and including a Zener diode for overvoltage protection in the gate circuit. The goal is to achieve low switching losses...
A control system for a DC-DC boost converter based on a deadbeat controller providing a finite duration transient in a small neighborhood of the equilibrium state is proposed. Deadbeat control is implemented by reducing a system matrix to the Frobenius form without transformation of state variables. A procedure to obtain deadbeat controller parameters for DC-DC boost converter is stated. Mathematical...
In multiple receivers wireless power transfer (WPT) systems, it is preferable to retune the resonant frequency of every receiver to the transmitter operating frequency in front of frequency mismatches. This paper discusses a proposal for electronic tuning for WPT receivers by means of a variable active switch-mode inductance. The proposed method benefits from the gyrator concept to emulate a variable...
This paper provides detailed analytical modeling and finite elements method (FEM) analysis of the thermal behavior of the medium frequency transformer (MFT). A comprehensive analytical model in form of a thermal network consisting of conduction, convection and radiation thermal resistances is generated based on the transformer physical structure, thus allowing for fast optimization of the MFT design...
Customers may have different power quality requirements, thus, the economic operational strategy can try to provide them with distinctive quality levels as customized service. An optimization based method is proposed in this paper to realize this functionality, offering the possibility that the customers can flexibly set and adjust their requirements. Converter interfaced distributed generators are...
This paper explains an optimum load analysis to reduce power loss in a direct AC/AC converter-based contactless electric vehicle charger. The converter has a fewer number of bi-directional switches than a matrix converter and it uses a resonant circuit to utilize zero-current switching. Output power and power loss depend on coupling factor and output load. A proper load value leads to low loss and...
With an increase in the wind turbine ratings, power converter ratings increase as well, thus raising the interest in medium voltage power converters. Switching frequency in said converters has to be kept below 1 kHz; hence the sampling frequency, which normally nowadays equals twice the switching frequency, is low as well. Sampling at low rates introduces additional non-idealities in the control of...
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