Influence of reactors on input harmonics of variable frequency drives
TL;DR: In this paper, a simulation is conducted to investigate the influence of the loading of the drives and the system source impedance on the performance of variable frequency drives (VFDs) in a power distribution system with VFDs as dominant loads in the oil field.
Abstract: AC line reactors and dc link reactors are widely used in variable frequency drives (VFDs) to improve the drive performance such as reducing input harmonics, improving the input power factor, and protecting the drives from surges, etc. The effectiveness of both types of reactors in reducing input harmonics is affected by many factors, including the loading of the drives and the system source impedance. In this paper, a simulation is conducted to investigate the influence of such factors. Two power distribution systems with VFDs as the dominant loads in the oil field are used as the case studies. The rules to evaluate the needs and effectiveness using ac line or dc link reactors are proposed for practical applications.
Citations
More filters
TL;DR: In this article, a power quality assessment and monitoring methodology is proposed to calculate VFD contribution to voltage distortion at the point of common coupling (PCC), considering the source short-circuit capacity and the existing vessel's power system harmonics.
Abstract: In maritime industry, high fuel costs encourage use of variable-frequency drives (VFDs) for energy-saving applications. However, introduction of such nonlinear loads in the vessel's power distribution network induces harmonics, which can lead to potential risks if are not predicted and controlled. In this paper, a systematic power-quality assessment and monitoring methodology is proposed to calculate VFD contribution to voltage distortion at the point of common coupling (PCC), considering the source short-circuit capacity and the existing vessel's power system harmonics. According to voltage harmonic distortion limits set by marine classification societies, design and sizing of appropriate harmonic attenuation filters is made, including ac and dc chokes and frequency-tuned passive filter options. The effectiveness of the proposed power-quality analyzing procedure is evaluated through a real practical example, which includes harmonic filter design for VFD retrofit application to fan and pump motors that operate constantly during sea-going operation in a typical tanker vessel. Power-quality field measurements obtained through a harmonic monitoring platform implemented on board verify that total voltage harmonic distortion and individual voltage harmonics at PCC are maintained below 5% and 3%, respectively, showing that design complies with relevant marine harmonic standards even in the worst operating case.
52 citations
TL;DR: Two approaches to improve the line detection and extraction method used in the original system are discussed, one intended for high-speed processing with lower accuracy, and the other providing high accuracy while incurring higher computational time expenses.
39 citations
TL;DR: The techniques and the main sensors used in the steelmaking industry to measure and quantify flatness defects in steel plates, sheets and strips are reviewed.
Abstract: Shape is a key characteristic to determine the quality of outgoing flat-rolled products in the steel industry. It is greatly influenced by flatness, a feature to describe how the surface of a rolled product approaches a plane. Flatness is of the utmost importance in steelmaking, since it is used by most downstream processes and customers for the acceptance or rejection of rolled products. Flatness sensors compute flatness measurements based on comparing the length of several longitudinal fibers of the surface of the product under inspection. Two main different approaches are commonly used. On the one hand, most mechanical sensors measure the tensile stress across the width of the rolled product, while manufacturing and estimating the fiber lengths from this stress. On the other hand, optical sensors measure the length of the fibers by means of light patterns projected onto the product surface. In this paper, we review the techniques and the main sensors used in the steelmaking industry to measure and quantify flatness defects in steel plates, sheets and strips. Most of these techniques and sensors can be used in other industries involving rolling mills or continuous production lines, such as aluminum, copper and paper, to name a few. Encompassed in the special issue, State-of-the-Art Sensors Technology in Spain 2013, this paper also reviews the most important flatness sensors designed and developed for the steelmaking industry in Spain.
32 citations
01 Sep 2016
TL;DR: In this paper, a daisy chain-like communication architecture for multilevel converters is presented. But it does not consider the effect of the control structure on the converter design.
Abstract: The benefits of modular multilevel converters come at a price: Their high level of complexity demands for an intricate design methodology and a sophisticated control structure. This is especially true for converters that need to be able to recover from short-circuits, grid faults, communication faults or module faults. In order to build a reliable system, it is thus important to understand the effect that the control structure has on the converter design. When protecting each module against over-voltages and overcurrents individually, the performance of the central controller is no longer immediately safety critical. This allows to communicate the switching times and measurements with a daisy-chain-like communication architecture that does not require point-to-point connections from the central controller to every module. The presented approach is verified by time-domain simulations and validated on a downscaled hardware prototype system.
10 citations
TL;DR: In this article, a brain emotional learning-based intelligent controller (BELBIC) is developed for the speed control of an interior permanent magnet synchronous motor (IPMSM).
Abstract: In this study, a brain emotional learning-based intelligent controller (BELBIC) is developed for the speed control of an interior permanent magnet synchronous motor (IPMSM). A novel and simple model of the IPMSM drive structure is established with the intelligent control system, which controls motor speed accurately without the use of any conventional PI controllers and is independent of motor parameters. This study is conducted in both real time and simulation with a new control plant for a laboratory 3 ph, 3.8 Nm IPMSM digital signal processor (DSP)-based drive system. This DSP-based drive system is then compared with conventional BELBIC and an optimized conventional PI controller. Results show that the proposed method performs better than the other controllers and exhibits excellent control characteristics, such as fast response, simple implementation, and robustness with respect to disturbances and manufacturing imperfections.
4 citations
References
More filters
TL;DR: In this paper, a new hybrid power filter is presented for three phase industrial power systems which include passive power factor correction equipment (PFC), which damps resonances occurring between line impedances and the PFC.
Abstract: A new hybrid power filter is presented for three phase industrial power systems which include passive power factor correction equipment (PFC). The hybrid filter damps resonances occurring between line impedances and the PFC. In addition, the hybrid filter topology can be used to compensate harmonic currents. The capacitors of the PFC, which generally cause resonant problems in harmonic distorted networks, can be used for passive filtering by connecting a transformer with a low magnetizing inductance in series hence creating a single harmonic trap. The primary side of the transformer is connected to a low VA-rated three-phase current controlled inverter which builds the active part of the hybrid topology. Simulation results and experimental results are presented verifying the damping and harmonic compensation performance of the proposed topology.
136 citations
"Influence of reactors on input harm..." refers background in this paper
...Adding AC line reactors or DC link reactors to VFDs, however, is the easiest way to reduce input harmonics of individual drives without requiring a complicated system analysis [1-8]....
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TL;DR: In this paper, a current source inverter capable of producing sinusoidal input/output (I/O) voltages and currents has been developed for driving an ac motor at variable speeds.
Abstract: With the application of gate turn-off thyristors (GTO's) and PWM control techniques, a current source inverter capable of producing sinusoidal input/output (I/O) voltages and currents has been developed. The sinusoidally modulated current is fed to the GTO's in the rectifier and inverter sections. The overvoltage-absorption capacitors connected to the ac input and output terminals function as a filter and, consequently, the waveforms of the input/output voltages and currents become sinusoidal. Because the PWM control utilizes the high-speed switching characteristics of the GTO's, the dc link current smoothing reactor and the overvoltage absorption capacitors are greatly reduced. The dc link voltage in the rectifier section is controlled to adjust the ac motor current. This is accomplished by using the firing angle shift method in conjunction with the method involving varying the width of the bypass gate pulses, which put the rectifier section into a bypass state. The current source GTO inverter is used to drive an 11-kW induction motor. As a result, excellent acceleration and deceleration characteristics are obtained, which verifies that the new current source inverter is quite suitable for driving an ac motor at variable speeds.
114 citations
04 Mar 2001
TL;DR: In this paper, a new hybrid power filter is presented for three phase industrial power systems which include passive power factor correction equipment (PFC), which damps resonances occurring between line impedances and the PFC.
Abstract: A new hybrid power filter is presented for three phase industrial power systems which include passive power factor correction equipment (PFC). The hybrid filter damps resonances occurring between line impedances and the PFC. In addition, the hybrid filter topology cam be used to compensate harmonic currents. The capacitors of the PFC, which generally cause resonant problems in harmonic distorted networks, can be used for passive filtering by connecting the magnetizing inductance of a transformer in series. The primary side of the transformer is connected to a low VA-rated three-phase inverter which builds the active part of the hybrid topology. Simulation results and experimental results are presented verifying the damping and harmonic compensation performance of the proposed topology.
54 citations
24 Oct 2005
TL;DR: In this paper, the impact of input voltage unbalance and sags on stresses in the dc-bus choke inductor and dcbus electrolytic capacitors of adjustable-speed drives (ASDs) was investigated.
Abstract: This paper investigates the impact of input voltage unbalance and sags on stresses in the dc-bus choke inductor and dc-bus electrolytic capacitors of adjustable-speed drives (ASDs). These stresses are primarily attributable to the rectifier's transition into single-phase operation, giving rise to low-order harmonic voltages (120 Hz, 240 Hz, etc.) that are applied to the dc-link filter components. These harmonics elevate the ac-flux densities in the dc choke core material significantly above values experienced during normal balanced-excitation conditions, causing additional core losses and potential magnetic saturation of the core. It is shown that the effects of voltage unbalances and sags on the dc-link capacitor lifetime will be the same when either line inductors or a dc-link choke inductor are used if the dc choke-inductance value is twice the value of the line inductance. Simulations and experimental tests are used to verify the accuracy of predictions provided by closed-form analysis and simulation for a 5-hp or 3730-W ASD system.
50 citations
Proceedings Article•
01 Jan 2004TL;DR: In this paper, the authors evaluated the performance of IGBT PWM current source induction machine drive in relation to industrial requirements and found that a high dynamic performance was achieved when, beneath a DC link inductance with suitable low inductivity, selected control methods, such as field oriented control and optimal state control, were applied.
Abstract: When rating the IGBT PWM current source induction machine drive in relation to industrial requirements, there are some important performance features to be studied. These are especially the dynamic control performance and the size and influence of the inductance in the DC link. These subjects and their interference are evaluated here, giving a basis for rating. With a high pulse frequency of the converters, with respect to the current ripple, only a low inductivity in the DC link is necessary, leading to low weight and volume and improving the ideal basic dynamic performance, too. A high dynamic performance, comparable to PWM voltage source induction machine drives, is reached when, beneath a DC link inductance with suitable low inductivity, selected control methods as field oriented control and, as chosen here, optimal state control, are applied. The basic performance is analysed and the the results are partially verified by measurements at a 7.5 kW test drive.
27 citations