Energies

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15 pages, 4786 KiB

Open AccessArticle

Application of a Tuned Inductor in a DC Power Supply with an Active Compensation Function

by Łukasz Ciepliński, Michał Gwóźdź and Rafał M. Wojciechowski

Energies 2022, 15(17), 6108; https://doi.org/10.3390/en15176108 - 23 Aug 2022

Cited by 3 | Viewed by 1067

This work focuses on the use of a one-phase direct current (DC) power supply equipped with a shunt active filter feature, which enabled the possibility of compensation (minimisation) of reactive and distortion power, generated by a group of loads, that was connected to [...] Read more.

This work focuses on the use of a one-phase direct current (DC) power supply equipped with a shunt active filter feature, which enabled the possibility of compensation (minimisation) of reactive and distortion power, generated by a group of loads, that was connected to the same power grid node as the power supply. A tuned inductor, which was included at the input of the controlled current source (constituting the main part of the power supply) allowed for an improvement in the quality of the compensation process, compared to a device with a fixed inductive filter This resulted in a visible reduction of the nonlinear distortions of the grid current. The improvement was made possible by extending the frequency response of the current source, which allowed to increase the dynamics of the current changes at the input of the power supply. This solution represents a new approach to such power devices. This work describes the principle of operation of the proposed converter solution and presents selected test results for a laboratory model of an electric system with this device. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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19 pages, 9698 KiB

Open AccessArticle

Load Estimation for Induction Heating Cookers Based on Series RLC Natural Resonant Current

by Zheng-Feng Li, Jhih-Cheng Hu, Ming-Shi Huang, Yi-Liang Lin, Chun-Wei Lin and Yu-Min Meng

Energies 2022, 15(4), 1294; https://doi.org/10.3390/en15041294 - 10 Feb 2022

Cited by 9 | Viewed by 2867

Abstract

In domestic induction heating applications, cookware can be considered an equivalent load in a series resistor–inductor–capacitor resonant converter. Therefore, the electrical parameters of an equivalent circuit change according to the cookware material, size and the cookware position on the heating coil. This study [...] Read more.

In domestic induction heating applications, cookware can be considered an equivalent load in a series resistor–inductor–capacitor resonant converter. Therefore, the electrical parameters of an equivalent circuit change according to the cookware material, size and the cookware position on the heating coil. This study proposes an online estimation method for detecting the cookware status, determining the material and estimating the equivalent heating resistance of cookware on an induction heating cooker (IHC) for power control. The proposed method could turn off the circuit in abnormal situations such as low equivalent heating coverage rate or non-ferromagnetic cookware and adjust the power in normal situations. In the method, a half-bridge series resonant converter (HBSRC) generates two test patterns with three resonant voltage pulses to detect cookware every 10 ms, only the current feedback information is needed to avoid the calculation loads and times necessary for complex signal operations in software. To verify the proposed method, a digital signal processor based HBSRC with 1000 W was constructed. The maximum errors between the estimated and measured resistance and inductance were 7.14% and 2.91%, respectively. Moreover, power control in emulated user operation reveal that the proposed method and control system can effectively estimate load online to detect cookware status and determine whether to turn off or vary the heating power for an IHC. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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19 pages, 8048 KiB

Open AccessArticle

Variable Speed Drive DC-Bus Voltage Dip Proofing

by Freeman Chiranga and Lesedi Masisi

Energies 2021, 14(24), 8257; https://doi.org/10.3390/en14248257 - 08 Dec 2021

Cited by 1 | Viewed by 1849

Abstract

This paper proposes a power electronic module that uses a switched capacitor for retaining the integrity of the dc-link voltage of a variable speed drive (VSD) during a 0.2 s short-term power interruption (STPI). Ride-through was achieved through switched capacitor onto the dc [...] Read more.

This paper proposes a power electronic module that uses a switched capacitor for retaining the integrity of the dc-link voltage of a variable speed drive (VSD) during a 0.2 s short-term power interruption (STPI). Ride-through was achieved through switched capacitor onto the dc bus. However, this technique presents a challenge of the high inrush currents during a ride through compensation. In this work both analytical and experimental investigations were conducted in order to reduce the in-rush currents and its impact on the performance of the VSD during the STPI. Inrush peak currents were reduced by approximately 90%. Experimental results showed torque pulsations of 12.8% and 14.3% at the start and end of dc-link voltage compensation, respectively. A method for sizing the switched capacitor and the inrush limiting resistors is proposed. This methodology is based on the use of readily available nameplate information of the VSD and the electric motor. The proposed module can be retrofitted to existing VSDs that are based on v/f control. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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17 pages, 7146 KiB

Open AccessArticle

Enhanced Boost Factor for Three-Level Quasi-Switched Boost T-Type Inverter

by Duc-Tri Do, Vinh-Thanh Tran and Minh-Khai Nguyen

Energies 2021, 14(13), 3920; https://doi.org/10.3390/en14133920 - 30 Jun 2021

Cited by 10 | Viewed by 1879

Abstract

A new modulation strategy has been introduced in this paper in order to enhance the boost factor for the three-level quasi-switched boost T-type inverter (3L-qSBT²I). Under this approach, the component rating of power devices is significantly decreased. Moreover, the use of [...] Read more.

A new modulation strategy has been introduced in this paper in order to enhance the boost factor for the three-level quasi-switched boost T-type inverter (3L-qSBT²I). Under this approach, the component rating of power devices is significantly decreased. Moreover, the use of a larger boost factor produces a smaller shoot-through current. This benefit leads to reducing the conduction loss significantly. Furthermore, the neutral voltage unbalance is also considered. The duty cycle of two active switches of a quasi-switched boost (qSB) network is redetermined based on actual capacitor voltages to recovery balance condition. Noted that the boost factor will not be affected by the proposed capacitor voltage balance strategy. The proposed method is taken into account to be compared with other previous studies. The operation principle and overall control strategy for this configuration are also detailed. The simulation and experiment are implemented with the help of PSIM software and laboratory prototype to demonstrate the accuracy of this strategy. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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20 pages, 7359 KiB

Open AccessArticle

Performance of a Shunt Active Power Filter for Unbalanced Conditions Using Only Current Measurements

by Saad F. Al-Gahtani and R. M. Nelms

Energies 2021, 14(2), 397; https://doi.org/10.3390/en14020397 - 12 Jan 2021

Cited by 7 | Viewed by 1729

Abstract

Shunt active power filters (APFs) are used to address power quality issues such as harmonic distortion and power system imbalance. Many control systems for shunt APFs demand measurements of voltages and currents for the determination of instantaneous real and reactive power signals. From [...] Read more.

Shunt active power filters (APFs) are used to address power quality issues such as harmonic distortion and power system imbalance. Many control systems for shunt APFs demand measurements of voltages and currents for the determination of instantaneous real and reactive power signals. From these signals, the reference currents of the shunt APF are calculated. A method of control for the APF shunt that only measures currents is proposed in this paper. The control method includes a modified technique to extract the positive and negative sequence components in the time domain. The reference currents in the shunt APF are calculated by the negative sequence components of the measured currents. Simulation and experimental results confirm the efficiency of this control scheme under ideal and non-ideal conditions. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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21 pages, 3958 KiB

Open AccessArticle

Analysis on Displacement Angle of Phase-Shifted Carrier PWM for Modular Multilevel Converter

by Qian Cheng, Chenchen Wang and Jian Wang

Energies 2020, 13(24), 6743; https://doi.org/10.3390/en13246743 - 21 Dec 2020

Cited by 8 | Viewed by 2399

Abstract

This paper provides theoretical and experimental discussions on the characteristics of the modular multilevel converter (MMC) when phase-shifted carrier sinusoidal pulse-width modulation (PSC-SPWM) is applied. Harmonic-cancellation characteristics of output voltage and circulating current are analyzed on the basis of a general implementation of [...] Read more.

This paper provides theoretical and experimental discussions on the characteristics of the modular multilevel converter (MMC) when phase-shifted carrier sinusoidal pulse-width modulation (PSC-SPWM) is applied. Harmonic-cancellation characteristics of output voltage and circulating current are analyzed on the basis of a general implementation of PSC-SPWM with two freedom displacement angles. Five available PSC-SPWM schemes with different carrier displacement angles were obtained, and a detailed performance comparison about output voltage and circulating current harmonic characteristics is presented. On the basis of the equivalent circuit with ideal transformer representation of the SMs, capacitor voltages affected by PSC-SPWM schemes are also briefly analyzed. The proposed PSC-SPWM schemes can unify two different cases of odd and even SM situations for output voltage and circulating current harmonic minimization, respectively. Lastly, the optimal schemes for practical MMC application were verified by simulation and experiments on an MMC prototype. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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15 pages, 6162 KiB

Open AccessArticle

Control Techniques for a Single-Phase Matrix Converter

by Marco Rivera, Sebastián Rojas, Carlos Restrepo, Javier Muñoz, Carlos Baier and Patrick Wheeler

Energies 2020, 13(23), 6337; https://doi.org/10.3390/en13236337 - 01 Dec 2020

Cited by 3 | Viewed by 2720

Abstract

The single-phase matrix converter is an AC-AC power topology which consists of six bidirectional switches and it is considered the key unit in cascade or multilevel configurations. In this paper, a comparison between two control techniques is presented, one based on a proportional-integral-derivative [...] Read more.

The single-phase matrix converter is an AC-AC power topology which consists of six bidirectional switches and it is considered the key unit in cascade or multilevel configurations. In this paper, a comparison between two control techniques is presented, one based on a proportional-integral-derivative control module with a pulse width modulator, and the other known as finite-state model predictive control. Simulation and experimental results are presented and discussed to demonstrate the feasibility and performance of both techniques. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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21 pages, 4125 KiB

Open AccessArticle

Local Carrier PWM for Modular Multilevel Converters with Distributed PV Cells and Circulating Current Reduction

by Zaid A. Aljawary, Santiago de Pablo, Luis Carlos Herrero-de Lucas and Fernando Martinez-Rodrigo

Energies 2020, 13(21), 5585; https://doi.org/10.3390/en13215585 - 26 Oct 2020

Cited by 2 | Viewed by 1682

Abstract

A new topology has been recently proposed for grid-connected photovoltaic (PV) systems, using modular multilevel converters (MMCs) and distributing PV panels throughout the MMC cells. This topology has two main advantages: it reduces the power losses related to moving the energy into the [...] Read more.

A new topology has been recently proposed for grid-connected photovoltaic (PV) systems, using modular multilevel converters (MMCs) and distributing PV panels throughout the MMC cells. This topology has two main advantages: it reduces the power losses related to moving the energy into the MMC capacitors from an external source, and it removes the losses and costs related to the DC to DC converters used to track the maximum power point on string converters or central converters, because that task is delegated to MMC cells. However, traditional pulse width modulation (PWM) techniques have many problems when dealing with this application: the distortion at the output increases to unacceptable values when MMC cells target different voltages. This paper proposes a new modulation technique for MMCs with different cell voltages, taking into account the measured cell voltages to generate switching sequences with more accurate timing. It also adapts the modulator sampling period to improve the transitions from level to level, an important issue to reduce the internal circulating currents. The proposed modulation has been validated using simulations that show a consistent behavior in the output distortion throughout a wide operation range, and it also reduces the circulating currents and cuts the conduction losses by half. The behavior of this new topology and this new modulation has been compared to the mainstream topology with external PV panels and also to a fixed carrier modulation. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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23 pages, 5266 KiB

Open AccessArticle

One Cycle Control of a PWM Rectifier a New Approach

by Rodrigo De A. Teixeira, Werbet L. A. Silva, Guilherme A. P. De C. A. Pessoa, Joao T. Carvalho Neto, Elmer R. L. Villarreal, Andrés O. Salazar and Alberto S. Lock

Energies 2020, 13(20), 5523; https://doi.org/10.3390/en13205523 - 21 Oct 2020

Cited by 3 | Viewed by 2432

Abstract

This paper analyzes a Digital Signal Processor (DSP) based One Cycle Control (OCC) strategy for a Power Factor Corrector (PFC) rectifier with Common-mode Voltage (CMV) immunity. It is proposed a strategy that utilizes an emulated-resistance-controller in closed-loop configuration to set the dc-link voltage [...] Read more.

This paper analyzes a Digital Signal Processor (DSP) based One Cycle Control (OCC) strategy for a Power Factor Corrector (PFC) rectifier with Common-mode Voltage (CMV) immunity. It is proposed a strategy that utilizes an emulated-resistance-controller in closed-loop configuration to set the dc-link voltage to achieve unity power factor (UPF). It is shown that if the PFC can achieve UPF condition and if the phase voltage is only affected by CMV, then phase current is free from CMV, as well as a lead-lag compensator (LLC) to average phase current. Full article

(This article belongs to the Special Issue Power Electronic Converters: Control and Applications)

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