Author
Eduardo P. Wiechmann
Other affiliations: Concordia University Wisconsin
Bio: Eduardo P. Wiechmann is an academic researcher from Concordia University. The author has contributed to research in topics: Voltage source & Pulse-width modulation. The author has an hindex of 4, co-authored 6 publications receiving 158 citations. Previous affiliations of Eduardo P. Wiechmann include Concordia University Wisconsin.
Papers
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TL;DR: In this article, a generalized analysis and design method for static voltage source inverters is presented, which utilizes the switching function concept to derive relevant analytical expressions, and digital simulation to obtain relevant design data.
Abstract: The relative success of the ``cut and try'' method has made the design of static power converters more of an art than a science. As a result, no comprehensive analysis approach is available today that can be used to design static converters with a good degree of confidence. Some important aspects of this problem-concerning mainly static voltage source inverters-are treated in this paper within the framework of a generalized analysis and design method. The subject approach utilizes the switching function concept to derive relevant analytical expressions, and digital simulation to obtain relevant design data.
78 citations
TL;DR: In this article, an upgraded method of power conversion is presented that eliminates both problems and allows bidirectional power flow which improves efficiency and simplifies cooling requirements, but the subject method requires a PWM rectifier and a pWM current source inverter.
Abstract: PWM voltage source inverters (VSI's) supplied from diode rectifiers are employed with most of today's static power supplies for variable frequency ac type loads. This method generates nonsinusoidal input and output voltage/current waveforms and yields poor system reliability. An upgraded method of power conversion is presented that eliminates both problems. In addition, it allows bidirectional power flow which improves efficiency and simplifies cooling requirements. The subject method requires a PWM rectifier and a PWM current source inverter. Advanced PWM techniques employed with both static Converters allow the minimization of all associated passive components.
51 citations
TL;DR: In this article, an uninterruptible power supplies (UPS) fed from current sources have been used to enhance system reliability without compromises in circuit complexity and/or system performance.
Abstract: Uninterruptible power supplies (UPS) fed from-current sources have so far received very little attention. Utilization of current sources with UPS is shown to enhance system reliability without compromises in circuit complexity and/or system performance.
24 citations
TL;DR: In this paper, the behavior of some well-known pulsewidth modulation (PWM) techniques under perturbation conditions of power semiconductor gating signals is investigated, and the effect of PWM timing errors on the output spectra of switch-mode converters is evaluated.
Abstract: The behavior of some well-known pulsewidth modulation (PWM) techniques is investigated under perturbation conditions of power semiconductor gating signals. An evaluation of different PWM techniques is performed considering the effect of PWM timing errors on the output spectra of switch-mode converters.
7 citations
18 Jun 1984
TL;DR: In this article, an upgraded PWM voltage source inverter is proposed for variable frequency ac type loads, which allows bidirectional power flow which improves efficiency and simplifies cooling requirements.
Abstract: PWM Voltage Source Inverters supplied from diode rectifiers are employed with most of today's static power supplies for variable frequency ac type loads. This method generates non sinusoidal input and output voltage/current waveforms and yields poor system reliability. This paper presents an upgraded method of power conversion that eliminates both problems. In addition it allows bidirectional power flow which improves efficiency and simplifies cooling requirements. The subject method requires a PWM rectifier and a PWM current source inverter. Advanced PWM techniques employed with both static converters allow the minimization of all associated passive components.
2 citations
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TL;DR: This paper presents an exhaustive review of three-phase improved power quality AC-DC converters configurations, control strategies, selection of components, comparative factors, recent trends, their suitability, and selection for specific applications.
Abstract: Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.
1,691 citations
TL;DR: In this article, a multiple feedback loop control scheme for single-phase voltage-source uninterruptible power supply (UPS) inverters with an L-C filter is presented.
Abstract: This paper presents the analysis and design of a multiple feedback loop control scheme for single-phase voltage-source uninterruptible power supply (UPS) inverters with an L-C filter. The control scheme is based on sensing the current in the capacitor of the load filter and using it in an inner feedback loop. An outer voltage feedback loop is also incorporated to ensure that the load voltage is sinusoidal and well regulated. A general state-space averaged model of the UPS system is first derived and used to establish the steady-steady quiescent point. A linearized small signal dynamic model is then developed from the system general model using perturbation and small-signal approximation. The linearized system model is employed to examine the incremental dynamics of the power circuit and select appropriate feedback variables for stable operation of the closed-loop UPS system. Experimental verification of a laboratory model of the UPS system under the proposed closed-loop operation is provided for both linear and nonlinear loads. It is shown that the control scheme offers improved performance measures over existing schemes, It is simple to implement and capable of producing nearly perfect sinusoidal load voltage waveform at moderate switching frequency and reasonable size of filter parameters. Furthermore, the scheme has excellent dynamic response and high voltage utilization of the DC source.
381 citations
10 Jul 2006
TL;DR: In this paper, a simple analytical expression for the current stress on the DC-link capacitor caused by the load-side inverter of a voltage D-link-converter system is derived.
Abstract: A simple analytical expression for the current stress on the DC-link capacitor caused by the load-side inverter of a voltage DC-link-converter system is derived. The DC-link capacitor-current RMS value is determined from the modulation depth and by the amplitude and the phase angle of the inverter output current assuming a sinusoidal inverter output current and a constant DC-link voltage. Despite neglecting the output-current ripple, the results of the analytical calculation are within 8% of measurements made from digital simulation and an experimental system, even if the output-current ripple is relatively high as in the case of low-frequency IGBT inverter systems. The simple analytical expression provides significant advantages over simulation methods for designing the DC-link capacitor of PWM converter systems.
350 citations
TL;DR: In this article, a scheme of combination of voltage-controlled and current-controlled PWM inverters for parallel operation of a single-phase uninterruptible power supply (UPS) is proposed.
Abstract: In this paper, a scheme of combination of voltage-controlled and current-controlled PWM inverters for parallel operation of a single-phase uninterruptible power supply (UPS) is proposed. The voltage-controlled PWM inverter (VCPI) unit as a master is developed to keep a constant sinusoidal wave output voltage. The current-controlled PWM inverter (CCPI) units are operated as slave controlled to track the distributive current. The power distribution center (PDC) performs the function of distributing the output current of each active unit. In this proposed scheme of parallel operation, each of the units can be designed as nearly independent, and the CCPI units do not need a PLL circuit for synchronization. As a result, the parallel operation of UPS is easy to implement and to expand system capacity. For the purpose of illustration, the system, including three single-phase units which operate in parallel, is analyzed and experimental results are given. >
342 citations
TL;DR: In this article, a control scheme based on the current deviation vector and satisfies both requirements was proposed, and the experimental results showed good agreement with the anticipated performance, however, in general, these requirements contradict each other.
Abstract: A high-performance current-controlled inverter must have a quick current response in transient state and low harmonic current content in steady state. However, in general, these requirements contradict each other. A novel control scheme is proposed which is based on the current deviation vector and satisfies both requirements. Experimental results showed good agreement with the anticipated performance.
239 citations