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A circuit topologies family of single-stage parallel uninterruptible AC/DC converter with high power factor is presented. The topology includes four sections, i.e. full bridge rectifier, parallel converter with power factor correction (PFC), uninterruptible power supply and fast output voltage regulation. The converter has lots of advantages such as: single stage power conversion, uninterruptible...
This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices for PWM control scheme and capacitive...
A single stage AC/DC converter with resonant model PFC has been deeply studied in this paper by mathematic analysis. The following results have been revealed: (1).The working conditions for the circuit have been derived and can be expressed by the formulas, which can be used to select the parameters of the circuit; (2). It has been proved that the bus voltage decreases if output power increases and...
Multilevel converters made of cascaded cells (MCCC) offer a high number of voltage levels with a given switch count. Many variants of the MCCC topology have been introduced over years. Mostly, only integer DC voltage ratios between the cascaded converter cells have been applied to its PWM modulation. This is mainly due to the non-uniform distribution of voltage vectors with the non-integer DC ratios...
Familiar special microprocessor with PWM pulse generator cannot provide enough PWM pulses for multi-modular converters or multilevel converters. Field programmable gate array (FPGA) is applied to implement the multichannel PWM pulse generator with no synchronization and communication trouble due to the single chip structure of FPGA compared with the multi-microprocessor scheme. A three-phase voltage...
This paper presents results of application of novel methods of synchronized pulse width modulation (PWM) to the open-end winding induction motor drives on the base of dual two-level voltage source inverters, with both single and separate DC voltage sources. The proposed control algorithms provide synchronous symmetrical control of the motor phase voltage, together with elimination of the common-mode...
A novel sliding mode control based on Hinfin theory has been developed to meet the nonlinear control of regenerative braking of electric vehicle(EV). By combining the sliding phase and the hitting phase, the parameter of the sliding mode controller is designed by Hinfin optimization procedure. In the scheme the sliding mode is ensured from the beginning of the response without the reaching problem...
A zero-voltage switching (ZVS) and zero-current switching (ZCS) two-transformer full-bridge PWM converter using the output-voltage-doubler is proposed in this paper. It is based on the phase-shifted full-bridge with series-connected two transformers (TTFB) which act as an output inductor as well as a main transformer. The TTFB converter achieves ZVS for all the switches inherently even at a light...
3-phase current-source SMES-UPS based on toroidal field superconducting coils (TFSC) is introduced in this paper, which serves for the exciting power supply (EPS) for TFSC when the power grid is in order, as well as for uninterrupted power supply (UPS) for the cryogenic and vacuum system once the deep voltage sag or other grid faults are detected. In the case of former, by controlling active and reactive...
Controlling of a specific harmonic by a switching converter with switching frequency lower than 1 kHz was originally implemented by two-level optimal pulse pattern with unsymmetrical switching angles, namely by OPUS-technique. That means, given a desired fundamental and one or more specific harmonics, the problem is to find the switching times (angles) that produce the fundamental while generating...
Many single and three-phase converters are well developed, and covered up in most of electric markets. It is used in many applications in power systems and machine drives. however, an exact definite output signal from the dc side still not recognized. The waveforms of output voltage and current demonstrate an imperfect dc signal and constitute losses, harmonic distortion, low power factor, and observed...
A novel control method which named waveform library control is presented in this paper. This control method is based on the rated open loop waveforms instead of mathematical model as usual. The proposed control method is easy to be realized because it only needs to collect the typical system response waveform without the mathematical model. As an exploration for power electronic circuit waveform control,...
Electronic cascaded systems are complex and extensively systems integrated with different converters. In general, there are two kinds of loads in these systems, constant power loads and constant voltage loads. The potential instability effected by constant power loads is analyzed with the power system of electric vehicle (EV) by impedance ratio criterion. The stability qualifications are given in...
Fuel cells for low or medium power deliver comparatively low voltages compared to the mains voltage at high currents. A high dc-link voltage is needed to feed in electrical energy from fuel cells to the mains via a voltage source inverter. Several well known DC/DC converters can be used to transform the varying fuel cell voltage to the requested amplitude of the dc-link-voltage. Besides transformerless...
This paper addresses the issues concerning the implementation of a pulse-width-modulation based sliding mode controller for boost converters. The methods of modelling the system and translation of the SM control equations for the PWM implementation are illustrated. It is shown that the control technique is easily realized with simple analog circuitries. The proposed system is verified by experimental...
A small-signal model for the asymmetrical half bridge flyback converter is presented. The effects of storage elements and peak current mode control on the transfer characteristics are investigated. The results show that the power stage of the studied converter is basically a fourth order system with two low-frequency poles and two high frequency poles. While the peak current mode control is applied,...
In this paper, DC-DC converters are viewed as one class of hybrid systems i.e. switched linear systems. A new mathematical model of switched linear systems-matrix coefficient polynomial description model is presented. An obvious description form of the relationship between the continuous variable and discrete variable is built, a new model of switched linear system of DC-DC converters, in which continuous...
In this paper, a new converter architecture that is based upon the buck topology and that allows a multi-interleaving technique is proposed. The converter provides automatic current sharing and improving current ripple cancellation effect. Multiphase buck converters with multi-interleaving technique perform better than with interleaving technique because the multi-interleaving technique can extend...
The paper introduces a DC-DC multiple converter based on push-pull forward topology and analyzes its operation principle in detail. It has some superiority in low voltage and high current situation. Then the design procedure of the power stage and control circuit is introduced. Finally 5 kW experimental equipment is accomplished
In this paper real, reactive power and voltage balance of the UPFC system is analyzed. Two advanced control schemes of UPFC have been proposed. One is the conventional coordination control scheme. In this scheme, the shunt converter of the UPFC controls the UPFC bus voltage and the DC-link voltage. The series converter controls the transmission line real and reactive power flow. By analysis, it is...
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