Research

18 pages, 6953 KiB

Open AccessFeature PaperArticle

Control Strategy for Electric Vehicle Charging Station Power Converters with Active Functions

by Fermín Barrero-González, María Isabel Milanés-Montero, Eva González-Romera, Enrique Romero-Cadaval and Carlos Roncero-Clemente

Energies 2019, 12(20), 3971; https://doi.org/10.3390/en12203971 - 18 Oct 2019

Cited by 19 | Viewed by 3293

Abstract

Based on the assumption that vehicles served by petrol stations will be replaced by Electric Vehicles (EV) in the future, EV public charging station facilities, with off-board fast chargers, will be progressively built. The power demand of these installations is expected to cause [...] Read more.

Based on the assumption that vehicles served by petrol stations will be replaced by Electric Vehicles (EV) in the future, EV public charging station facilities, with off-board fast chargers, will be progressively built. The power demand of these installations is expected to cause great impact on the grid, not only in terms of peak power demanded but also in terms of power quality, because most battery chargers behave as non-linear loads. This paper presents the proposal of a novel comprehensive global control strategy for the power electronic converters associated with bidirectional three-phase EV off-board fast chargers. The Charging Station facility Energy Management System (CS-EMS) sends to each individual fast charger the active and reactive power setpoints. Besides, in case the charger has available capacity, it is assigned to compensate a fraction of the harmonic current demanded by other loads at the charging facility. The proposed approach works well under distorted and unbalanced grid voltages. Its implementation results in improvement in the power quality of each fast charger, which contributes to improvement in the power quality at the charging station facility level, which can even provide ancillary services to the distribution network. Simulation tests are conducted, using a 100 kW power electronic converter model, under different load and grid conditions, to validate the effectiveness and the applicability of the proposed control strategy. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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14 pages, 7872 KiB

Open AccessArticle

Analysis of Fault-Tolerant Operation Capabilities of an Isolated Bidirectional Current-Source DC–DC Converter

by Andrei Blinov, Roman Kosenko, Andrii Chub and Volodymyr Ivakhno

Energies 2019, 12(16), 3203; https://doi.org/10.3390/en12163203 - 20 Aug 2019

Cited by 10 | Viewed by 2881

Abstract

Reliable and predictable operation of power electronics is of increasing importance due to continuously growing penetration of such systems in industrial applications. This article focuses on the fault-tolerant operation of the bidirectional secondary-modulated current-source DC–DC converter. The study analyzes possible topology reconfigurations in [...] Read more.

Reliable and predictable operation of power electronics is of increasing importance due to continuously growing penetration of such systems in industrial applications. This article focuses on the fault-tolerant operation of the bidirectional secondary-modulated current-source DC–DC converter. The study analyzes possible topology reconfigurations in case an open- or short-circuit condition occurs in one of the semiconductor devices. In addition, multi-mode operation based on topology-morphing is evaluated to extend the operating range of the case study topology. The influence of post-failure modes on the functionality and performance is analyzed with a 300 W converter prototype. It is demonstrated that failure of one transistor in the current-source side can be mitigated without dramatic loss in the efficiency at maximum power, while preserving bidirectional operation capability. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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17 pages, 5551 KiB

Open AccessArticle

A Modified Step-Up DC-DC Flyback Converter with Active Snubber for Improved Efficiency

by Cristian Pesce, Javier Riedemann, Ruben Pena, Werner Jara, Camilo Maury and Rodrigo Villalobos

Energies 2019, 12(11), 2066; https://doi.org/10.3390/en12112066 - 30 May 2019

Cited by 11 | Viewed by 3872

Abstract

The research on DC-DC power converters has been a matter of interest for years since this type of converter can be used in a wide range of applications. The main research is focused on increasing the converter voltage gain while obtaining a good [...] Read more.

The research on DC-DC power converters has been a matter of interest for years since this type of converter can be used in a wide range of applications. The main research is focused on increasing the converter voltage gain while obtaining a good efficiency and reliability. Among the different DC-DC converters, the flyback topology is well-known and widely used. In this paper, a novel high efficiency modified step-up DC-DC flyback converter is presented. The converter is based on a N-stages flyback converter with parallel connected inputs and series-connected outputs. The use of a single main diode and output capacitor reduces the number of passive elements and allows for a more economical implementation compared with interleaved flyback topologies. High efficiency is obtained by including an active snubber circuit, which returns the energy stored in the leakage inductance of the flyback transformers back to the input power supply. A 4.7 kW laboratory prototype is implemented considering four flyback stages with an input voltage of 96 V and an output voltage of 590 V, obtaining an efficiency of 95%. The converter operates in discontinuous current mode then facilitating the output voltage controller design. Experimental results are presented and discussed. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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22 pages, 1713 KiB

Open AccessArticle

Development and 24 Hour Behavior Analysis of a Peak-Shaving Equipment with Battery Storage

by Wilson Cesar Sant’Ana, Robson Bauwelz Gonzatti, Germano Lambert-Torres, Erik Leandro Bonaldi, Bruno Silva Torres, Pedro Andrade de Oliveira, Rondineli Rodrigues Pereira, Luiz Eduardo Borges-da-Silva, Denis Mollica and Joselino Santana Filho

Energies 2019, 12(11), 2056; https://doi.org/10.3390/en12112056 - 29 May 2019

Cited by 7 | Viewed by 2524

Abstract

This paper presents the development of a peak-shaving equipment, composed by a multilevel converter in a cascaded H-bridge topology and battery banks on the DC links. Between specific time periods, when the demand is higher, the equipment injects active power from the batteries [...] Read more.

This paper presents the development of a peak-shaving equipment, composed by a multilevel converter in a cascaded H-bridge topology and battery banks on the DC links. Between specific time periods, when the demand is higher, the equipment injects active power from the batteries into the grid to provide support to the system. During the other times of the day, when the demand is lower, the converter charges its battery banks with the exceeding (and low producing cost) energy from the grid. The charge and discharge control algorithms are implemented in a digital signal processor (DSP). The precise time of the day information is obtained from a real-time-clock from a global positioning system module (GPS), which communicates with the DSP through the serial interface. This paper presents the control algorithms and experimental results obtained in a 24 h continuous operation of the equipment. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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15 pages, 5006 KiB

Open AccessArticle

Voltage Source Operation of the Energy-Router Based on Model Predictive Control

by Indrek Roasto, Oleksandr Husev, Mahdiyyeh Najafzadeh, Tanel Jalakas and Jose Rodriguez

Energies 2019, 12(10), 1892; https://doi.org/10.3390/en12101892 - 17 May 2019

Cited by 19 | Viewed by 2742

Abstract

The energy router (ER) is regarded as a key component of microgrids. It is a converter that interfaces the microgrid(s) with the utility grid. The energy router has a multiport structure and bidirectional energy flow control. The energy router concept can be implemented [...] Read more.

The energy router (ER) is regarded as a key component of microgrids. It is a converter that interfaces the microgrid(s) with the utility grid. The energy router has a multiport structure and bidirectional energy flow control. The energy router concept can be implemented in nearly zero energy buildings (NZEB) to provide flexible energy management. We propose a concept where ER is working as a single grid-forming converter with a predefined voltage reference. The biggest challenge is to maintain regulated voltage and frequency inside the NZEB in the idle operation mode, where traditional regulators, e.g., proportional-resonant (PR), proportional-integral-derivative (PID), will not meet the control design requirements and could have unstable behavior. To gain the stability of the system, we propose model predictive control (MPC). The design of the MPC algorithm is explained. A simulation software for power electronics (PLECS) is used to simulate the proposed algorithm. Finally, the simulation results are verified on an experimental prototype. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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21 pages, 7320 KiB

Open AccessArticle

Modular Self-Balancing Battery Charger Concept for Cost-Effective Power-Assist Wheelchairs

by Ilya Galkin, Andrei Blinov, Ievgen Verbytskyi and Denys Zinchenko

Energies 2019, 12(8), 1526; https://doi.org/10.3390/en12081526 - 23 Apr 2019

Cited by 16 | Viewed by 3591

Abstract

The paper deals with a power charger capable of quick simultaneous charging of several unevenly discharged batteries. The charger is designed for use in conjunction with a recently developed power-assist wheelchair composed of two armrest modules associated with wheels—each with its own motor, [...] Read more.

The paper deals with a power charger capable of quick simultaneous charging of several unevenly discharged batteries. The charger is designed for use in conjunction with a recently developed power-assist wheelchair composed of two armrest modules associated with wheels—each with its own motor, driver and battery. Uneven discharge of the batteries is very possible in this application. Taking into account the charging power and energy comparable with the most powerful household electrical devices, the refreshing of these batteries and integration of the entire power supply chain into the household grid become a topical and challenging task. Solving of this task requires a special charger that has several channels and can unevenly apply charging power to these channels. At the same time, the charger must not generate current harmonics or reactive power, must operate with good efficiency and satisfy size constraints. In the given research, a configuration of several interleaved isolated single-ended primary-inductor converters is studied. The synthesized mathematical model of the proposed charger provides data about its static and dynamic characteristics while its experimental investigation focuses on operation details (power losses, control features etc.). The obtained results prove that the proposed concept complies with the above-mentioned requirements and can be applied in the discussed application. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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16 pages, 5200 KiB

Open AccessArticle

Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support

by Fermín Barrero-González, Victor Fernão Pires, José L. Sousa, João F. Martins, María Isabel Milanés-Montero, Eva González-Romera and Enrique Romero-Cadaval

Energies 2019, 12(6), 972; https://doi.org/10.3390/en12060972 - 13 Mar 2019

Cited by 17 | Viewed by 3317

Abstract

The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually [...] Read more.

The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually designed to obtain the maximum energy from the panels. The most recent approach to these issues involves new inverter-based solutions. This paper proposes a novel comprehensive control strategy for the power electronic converters associated with PV installations to improve the operational performance of a four-wire LV distribution network. The objectives are to try to balance the currents demanded by consumers and to compensate the reactive power demanded by them at the expense of the remaining converters’ capacity. The strategy is implemented in each consumer installation, constituting a decentralized or distributed control and allowing its practical implementation based on local measurements. The algorithms were tested, in a yearly simulation horizon, on a typical Portuguese LV network to verify the impact of the high integration of the renewable energy sources in the network and the effectiveness and applicability of the proposed approach. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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12 pages, 6185 KiB

Open AccessArticle

An Active Common-Mode Voltage Canceler for PWM Converters in Wind-Turbine Doubly-Fed Induction Generators

by Amr. S. Zalhaf, Mazen Abdel-Salam and Mahmoud Ahmed

Energies 2019, 12(4), 691; https://doi.org/10.3390/en12040691 - 21 Feb 2019

Cited by 9 | Viewed by 3094

Abstract

Wind energy integration in power grids is increasing day by day to reduce the use of fossil fuels, and consequently greenhouse gas emissions. Using the pulse-width modulated (PWM) power converters in wind turbine generators, specifically in doubly-fed induction generators, results in generating a [...] Read more.

Wind energy integration in power grids is increasing day by day to reduce the use of fossil fuels, and consequently greenhouse gas emissions. Using the pulse-width modulated (PWM) power converters in wind turbine generators, specifically in doubly-fed induction generators, results in generating a common-mode voltage (CMV). This common-mode voltage causes a flow of common-mode current (CMC) that leaks through the stray capacitances in the generator structure. These currents impose a voltage on the generator bearing which may deteriorate them. In the current work, an active common-mode voltage canceler (ACMVC) is developed to eliminate the CMV produced by a PWM converter. The ACMVC generates a compensating voltage at the converter terminals to eliminate the CMV with a subsequent reduction of the voltage stress on the generator bearing. This compensating voltage has the same amplitude as CMV, but opposite polarity. A simulation of the ACMVC model is performed using the PSCAD/EMTDC (Electromagnetic Transient Design and Control) software package. Results confirm the effectiveness of ACMVC in canceling not only the CMV but the CMC and bearing voltage as well. In addition, the relationship between the rise time of CMV and the peak value of CMC is investigated. Full article

(This article belongs to the Special Issue Power Electronic Systems for Efficient and Sustainable Energy Supply)

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