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In order to improve the ability of harmonic reduction at DC link of multi-pulse rectifier (MPR), the harmonic reduction mechanism at DC link of two kinds of 24-pulse rectifiers with double-tapped interphase reactor (IPR) or auxiliary single-phase full-wave rectifier (ASFR) was investigated. According to the configuration and Ampere-Turn balance with double-tapped IPR and single full wave rectifier,...
In this paper we propose a second-order harmonic-enhanced circuit design in an energy harvesting receiver. For accurate location detection, a LC resonator together with harmonic-enhanced coupler is placed after a dual-band Yagi-Uda antenna. This design helps the beamforming power transmitter to do maximum power transfer when an EH-receiver moves into the power transfer coverage region and its stored...
A new 3-phase current controlled PFC rectifier has been proposed in this paper. Phase difference in between input voltage and current is minimized using an a-periodic control signal generated using input current, phase angle of input voltage, and output voltage. A 1V (P-P) 5KHz triangular wave is used here to generate PWM signal. Simple PID controllers have been added with the controller of the rectifier...
Conventional three-phase diode or controlled rectifiers generate current harmonics which affect power quality of distribution networks. This paper presents a novel topology with a front end Modular Multi-Parallel Rectifiers (MMR): Active DC link current controllers are utilized for each rectifier connected to a common DC link capacitor which can reduce line current harmonics emissions significantly...
The aim of this paper is to bring new contribution and new technology for locomotive especially for WAP-7. Recent advance technology was proposed on locomotive by ABB, ALSTOM, HITACHI, etc. but still there is a disturbance in converters by converting AC/DC/AC. This proposed topology called multilevel inverter using PIC reduces the total harmonic distortion and also while triggering the gates in inverter...
Generated harmonic current as a consequence of employing power electronics converter is known as an important power quality issue in distribution networks. From industry point of view complying with international standards is mandatory, however cost and efficiency are two other important features, which need to be considered in order to be competitive in the market. Therefore, having a flexibility...
Diode rectifier front ends with large DC bus capacitors used in Variable Frequency Drives (VFDs) draw discontinuous current from the power system resulting in poor input power factor and high input current distortion. In case of single-phase AC to DC rectifiers, the single-phase boost converter is popular and effective in improving the input power factor and reducing the input current harmonics. However,...
This paper reports on tests performed to determine the response of common low voltage power supplies when their AC power feed is distorted by various types and levels of harmonic distortion. Such distortion could be a possible form of IEMI attack on a facility. It is found that switched mode power supplies are immune to such attacks, but rectifier type supplies are very susceptible, if the distortion...
This paper describes a near unity power factor rectifier with low harmonics. Small size, low cost, high efficiency are the main features of this rectifier configuration. This configuration makes use of three active bidirectional switches to achieve power factor correction. The switches are rated at a small percentage of total power processed and is switched at a very low frequency. The analysis of...
With the development of power electronics, the power quality of AC power supply is increasingly paid attention to. In general, diode uncontrolled rectifier and thyristor phase controlled rectifier are adopted for AC/DC convertion, which inject plentiful harmonic and reactive power into AC mains, and result in serious pollution. So lots of reseaches have been focus on high input power factor and minimum...
In the type test process of a certain type AC-Driven Electrical Multiple Unit (EMU), because of the logical error of pulse rectifier's carrier phase shifting control, line side harmonic content is amplified. Transient value of line voltage increases and the normal work of other EMU under the same power supply arm is impacted. Through harmonic analysis on test data and line side harmonic characteristic...
`Thin' power electronics concentrates on the design of minimal and cost effective power converters. Part of the research effort targets the direct processing of an AC input to an AC output without the use of an intermediate DC stage. Particular examples include the inverterless active filter and the controllable network transformer, both of which in their simplest form employ a buck switcher as the...
Converters using active switches can improve harmonic components of input current and power factor. Moreover, these converters contribute to the footprint downsizing. However, increase of switching losses and EMI due to high frequency switching is one challenge of these types of converters. This paper proposes a new active rectifier circuit topology, which can reduce the switching losses and EMI with...
A single-phase five level pulse width modulation (PWM) rectifier is proposed. The control scheme is using the sinusoidal PWM technique to improve the power factor and to achieve a lower total harmonic distortion (THD) for the proposed rectifier. The control method is also aimed to obtain a nearly sinusoidal line current. Five-level PWM output is generated at the ac terminal. The proposed topology...
Random pulse width modulation (RPWM) technique has been employed to generate the control signals of Vienna-type rectifier. This technique is compared to two conventional techniques (Hysteresis-band and ramp comparison with fix frequency carrier signal). Simulation results are illustrated for three approaches. The results verify significantly reduction of high frequency harmonics magnitude; and consequently...
This paper presents an investigation into the relationship between voltage fluctuation and inter-harmonics in distribution network based on modulation theory. It is verified by Matlab/Simulink simulation and physical tests. The modulation theory, commonly used for analysis of harmonics, is used to analyze the inter-harmonics. A switching function of a rectangle waveform is used to describe a diode...
This paper addresses control techniques aimed at improving light-load efficiency and reducing harmonic distortion in digitally controlled single-phase boost power factor correction (PFC) rectifiers. Based on a discontinuous conduction mode (DCM) detection circuit, it is shown how an extension to the predictive current control law leads to improved current regulation over wide load range in both continuous...
This paper presents a shunt active power filter application mainly for source current harmonic elimination. The proposed control method is based on instantaneous reactive power theory. A three-phase voltage source inverter bridge with a dc bus capacitor is used as an APF. It requires measuring the source currents with reduced number of current sensors than the existing methods. The source currents...
Because of a lot of advantages, there are extensive motivations to utilize four-switch converters in industrial applications. Many modulation techniques have been proposed to design a good four-switch converter that is less sensitive to DC link voltage fluctuations, and have low AC currents THD and at the same time low distortion in the uncontrolled phase. Among various techniques, design procedure...
This paper presents a new soft switched topology for losses reduction in a three-phase four-wire shunt active power filter (SAPF). The soft-switching technique not only offers a reduction in switching loss and thermal requirement, but also allows the possibility of high frequency and snubberless operation. Improved circuit performance and efficiency as well as reduction of EMI emission can be achieved...
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