Editorial

3 pages, 172 KiB

Open AccessEditorial

Special Issue “Advances in Control of Power Electronic Converters”

by Oswaldo Lopez-Santos and Germain Garcia

Appl. Sci. 2021, 11(10), 4585; https://0-doi-org.brum.beds.ac.uk/10.3390/app11104585 - 18 May 2021

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The use of power converters has grown in the last years with the advances in photovoltaic and wind based power generation systems, and the progress in modern concepts such as microgrids and electric mobility. A consequence has been the development of devices allowing [...] Read more.

The use of power converters has grown in the last years with the advances in photovoltaic and wind based power generation systems, and the progress in modern concepts such as microgrids and electric mobility. A consequence has been the development of devices allowing for the exchange of energy among different distribution buses, and feeding AC or DC loads from low DC voltage levels, whose proper operation is achieved by means of specialized control systems. Simultaneously, the power converters used for conventional industrial applications have evolved thanks to the application of new control methods, and the combination of these with well-established techniques. This special issue contributes theoretical and practical advances to the state-of-the-art field at the crossroads of power electronics and control systems. The seven included papers cover particular applications requiring either DC–DC, DC–AC or AC–DC conversion stages. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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19 pages, 2107 KiB

Open AccessArticle

LMI-Fuzzy Control Design for Non-Minimum-Phase DC-DC Converters: An Application for Output Regulation

by Carlos Andrés Torres-Pinzón, Leonel Paredes-Madrid, Freddy Flores-Bahamonde and Harrynson Ramirez-Murillo

Appl. Sci. 2021, 11(5), 2286; https://0-doi-org.brum.beds.ac.uk/10.3390/app11052286 - 04 Mar 2021

Cited by 9 | Viewed by 2191

Abstract

Robust control techniques for power converters are becoming more attractive because they can meet with most demanding control goals like uncertainties. In this sense, the Takagi-Sugeno (T-S) fuzzy controller based on linear matrix inequalities (LMI) is a linear control by intervals that has [...] Read more.

Robust control techniques for power converters are becoming more attractive because they can meet with most demanding control goals like uncertainties. In this sense, the Takagi-Sugeno (T-S) fuzzy controller based on linear matrix inequalities (LMI) is a linear control by intervals that has been relatively unexplored for the output-voltage regulation problem in switching converters. Through this technique it is possible to minimize the disturbance rejection level, satisfying constraints over the decay rate of state variables as well as the control effort. Therefore, it is possible to guarantee, a priori, the stability of the large-signal converters in a broad operation domain. This work presents the design of a fuzzy control synthesis based on a T-S fuzzy model for non-minimum phase dc-dc converters, such as boost and buck-boost. First, starting from the canonical bilinear converters expression, a Takagi-Sugeno (T-S) fuzzy model is obtained, allowing to define the fuzzy controller structure through the parallel distributed compensation technique (PDC). Finally, the fuzzy controller design based on LMIs is solved for the defined specification in close loop through MATLAB toolbox LMI. Simulations and experimental results of a 60 W prototype are presented to verify theoretical predictions. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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21 pages, 5128 KiB

Open AccessArticle

A Sliding Surface for Controlling a Semi-Bridgeless Boost Converter with Power Factor Correction and Adaptive Hysteresis Band

by José Robinson Ortiz-Castrillón, Gabriel Eduardo Mejía-Ruiz, Nicolás Muñoz-Galeano, Jesús María López-Lezama and Juan Bernardo Cano-Quintero

Appl. Sci. 2021, 11(4), 1873; https://0-doi-org.brum.beds.ac.uk/10.3390/app11041873 - 20 Feb 2021

Cited by 10 | Viewed by 2092

Abstract

This paper proposes a new sliding surface for controlling a Semi-Bridgeless Boost Converter (SBBC) which simultaneously performs Power Factor Correction (PFC) and DC bus regulation. The proposed sliding surface is composed of three terms: First, a normalized DC voltage error term controls the [...] Read more.

This paper proposes a new sliding surface for controlling a Semi-Bridgeless Boost Converter (SBBC) which simultaneously performs Power Factor Correction (PFC) and DC bus regulation. The proposed sliding surface is composed of three terms: First, a normalized DC voltage error term controls the DC bus and rejects DC voltage disturbances. In this case, the normalization was performed for increasing system robustness during start-up and large disturbances. Second, an AC current error term implements a PFC scheme and guarantees fast current stabilization during disturbances. Third, an integral of the AC current error term increases stability of the overall system. In addition, an Adaptive Hysteresis Band (AHB) is implemented for keeping the switching frequency constant and reducing the distortion in zero crossings. Previous papers usually include the first and/or the second terms of the proposed sliding surface, and none consider the AHB. To be best of the author’s knowledge, the proposed Sliding Mode Control (SMC) is the first control strategy for SBBCs that does not require a cascade PI or a hybrid PI-Sliding Mode Control (PI-SMC) for simultaneously controlling AC voltage and DC current, which gives the best dynamic behavior removing DC overvoltages and responding fast to DC voltage changes or DC load current perturbations. Several simulations were carried out to compare the performance of the proposed surface with a cascade PI control, a hybrid PI-SMC and the proposed SMC. Furthermore, a stability analysis of the proposed surface in start-up and under large perturbations was performed. Experimental results for PI-SMC and SMC implemented in a SBBC prototype are also presented. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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13 pages, 2600 KiB

Open AccessFeature PaperArticle

Robust LQR Control for PWM Converters with Parameter-Dependent Lyapunov Functions

by Nedia Aouani and Carlos Olalla

Appl. Sci. 2020, 10(21), 7534; https://0-doi-org.brum.beds.ac.uk/10.3390/app10217534 - 26 Oct 2020

Cited by 7 | Viewed by 2706

Abstract

This paper presents a novel framework for robust linear quadratic regulator (LQR)-based control of pulse-width modulated (PWM) converters. The converter is modeled as a linear parameter-varying (LPV) system and the uncertainties, besides their rate of change, are taken into account. The proposed control [...] Read more.

This paper presents a novel framework for robust linear quadratic regulator (LQR)-based control of pulse-width modulated (PWM) converters. The converter is modeled as a linear parameter-varying (LPV) system and the uncertainties, besides their rate of change, are taken into account. The proposed control synthesis method exploits the potential of linear matrix inequalities (LMIs), assuring robust stability whilst obtaining non-conservative results. The method has been validated in a PWM DC–DC boost converter, such that it has been shown, with the aid of simulations, that improved robustness and improved performance properties can be achieved, with respect to previously proposed approaches. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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15 pages, 4031 KiB

Open AccessArticle

ADC Quantization Effects in Two-Loop Digital Current Controlled DC-DC Power Converters: Analysis and Design Guidelines

by Catalina González-Castaño, Carlos Restrepo, Roberto Giral, Enric Vidal-Idiarte and Javier Calvente

Appl. Sci. 2020, 10(20), 7179; https://0-doi-org.brum.beds.ac.uk/10.3390/app10207179 - 15 Oct 2020

Cited by 3 | Viewed by 2677

Abstract

This paper analyzes the presence of undesired quantization-induced perturbations (QIP) in a dc-dc buck-boost converter using a two-loop digital current control. This work introduces design conditions regarding control laws gains and signal quantization to avoid the quantization effects due to the addition of [...] Read more.

This paper analyzes the presence of undesired quantization-induced perturbations (QIP) in a dc-dc buck-boost converter using a two-loop digital current control. This work introduces design conditions regarding control laws gains and signal quantization to avoid the quantization effects due to the addition of the outer voltage loop in a digital current controlled converter. The two-loop controller is composed of a multisampled average current control (MACC) in the inner current-programmed loop and a proportional-integrator compensator at the external loop. QIP conditions have been evaluated through simulations and experiments using a digitally controlled pulse width modulation (DPWM) buck-boost converter. A 400 V 1.6 kW proof-of-concept converter has been used to illustrate the presence of QIP and verify the design conditions. The controller is programmed in a digital signal controller (DSC) TMS320F28377S with a DPWM with 8.96-bit equivalent resolution, a 12-bit ADC for current sampling, and a 12-bit ADC for voltage sampling or a 16-bit ADC for voltage error sampling. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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21 pages, 4050 KiB

Open AccessArticle

Analysis of Subharmonic Oscillation and Slope Compensation for a Differential Boost Inverter

by Abdelali El Aroudi, Mohamed Al-Numay, Reham Haroun and Meng Huang

Appl. Sci. 2020, 10(16), 5626; https://0-doi-org.brum.beds.ac.uk/10.3390/app10165626 - 13 Aug 2020

Cited by 3 | Viewed by 2556

Abstract

This paper focuses on the steady-behavior of a differential boost inverter used for generating a sinewave AC voltage in rural areas. The analysis of its dynamics will be performed using an accurate approach based on discrete time models and Floquet theory and adopting [...] Read more.

This paper focuses on the steady-behavior of a differential boost inverter used for generating a sinewave AC voltage in rural areas. The analysis of its dynamics will be performed using an accurate approach based on discrete time models and Floquet theory and adopting a quasi-static approximation. In particular, the undesired subharmonic oscillation exhibited by the inverter will be analyzed and its boundary in the parameter space will be predicted and delimited. Combining analytical expressions and computational procedures to determine the quasi-static duty cycle, subharmonic oscillation is accurately predicted. It is found that subharmonic oscillation takes place at critical values of the sinewave voltage reference cycle, which can cause distortion to the input current and degrade the harmonic content of the output voltage. The results provide useful information for the design of the boost inverter to avoid distortion caused by subharmonic oscillation. Namely, the minimum value of the compensation slope and the maximum proportional gain of the AC output voltage controller guaranteeing a pure sinewave voltage and clean inductor current during the entire AC cycle will be determined. Numerical simulations performed on the switched model implemented using PSIM© software confirm the theoretical predictions. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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20 pages, 7992 KiB

Open AccessArticle

Double Sliding-Surface Multiloop Control Reducing Semiconductor Voltage Stress on the Boost Inverter

by Oswaldo López-Santos and Germain García

Appl. Sci. 2020, 10(14), 4912; https://0-doi-org.brum.beds.ac.uk/10.3390/app10144912 - 17 Jul 2020

Cited by 6 | Viewed by 1732

Abstract

Sliding-mode control (SMC) has been successfully applied to boost inverters, which solves the tracking problem of imposing sinusoidal behavior to the output voltage despite the coupled or decoupled operation of both boost cells in the converter. Most of the results reported in the [...] Read more.

Sliding-mode control (SMC) has been successfully applied to boost inverters, which solves the tracking problem of imposing sinusoidal behavior to the output voltage despite the coupled or decoupled operation of both boost cells in the converter. Most of the results reported in the literature were obtained using the conventional cascade-control structure involving outer loops that generate references for one or two sliding surfaces defined using linear combinations of inductor currents and capacitor voltages. As expected, all proposed methods share the inherent robustness and insensitivity to the uncertainties of SMC, which are the reasons why one of the few comparison criteria between them is the simplicity of their implementation that is evaluated according to the required measurements and mathematical operations. Furthermore, the slight differences between the obtained dynamic performances do not allow a clear distinction of the best solution. This study presents a new SMC approach applied to a boost inverter in which two boost cells are independently commutated. Each of these boost cells integrates an outer loop, enforcing the tracking of harmonic-enriched waveforms to the capacitor voltage. Although this approach increases by two the number of measurements and requires multiloop controllers, it allows effective alleviation of the semiconductor voltage stress by reducing the required voltage gain. A complete analytical study using harmonic balance technique allows deducing a simplified model allowing to obtain a PI controller valid into to the whole set of operation conditions. The several simulation results completely verified the potential of the control proposal and the accuracy of the employed methods. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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19 pages, 8015 KiB

Open AccessArticle

Improvement of Power Converters Performance by an Efficient Use of Dead Time Compensation Technique

by Sheeraz Iqbal, Ai Xin, Mishkat Ullah Jan, Mohamed Abdelkarim Abdelbaky, Haseeb Ur Rehman, Salman Salman, Muhammad Aurangzeb, Syed Asad Abbas Rizvi and Noor Ahmad Shah

Appl. Sci. 2020, 10(9), 3121; https://0-doi-org.brum.beds.ac.uk/10.3390/app10093121 - 29 Apr 2020

Cited by 17 | Viewed by 2516

Abstract

The advent of renewable energy resources and distributed energy systems herald a new set of challenges of power quality, efficient distribution, and stability in the power system. Furthermore, the power electronic converters integration has been increased in interfacing alternate energy systems and industries [...] Read more.

The advent of renewable energy resources and distributed energy systems herald a new set of challenges of power quality, efficient distribution, and stability in the power system. Furthermore, the power electronic converters integration has been increased in interfacing alternate energy systems and industries with the transmission and distribution grids. Owing to the intermittency of renewable energy resources and the application of power electronic converters the power distribution faces peculiar challenges. The dead-time effects are among the main challenges, which leads to the distortion of third harmonics, phase angle, torque pulsation, and induction motor current, causing severe quality problems for power delivery. To tackle these problems, this paper proposes a novel dead time compensation technique for improving the power quality parameters and improving the efficiency of power converters. The proposed model is simulated in MATLAB and the parametric equations are plotted against the corresponding parametric values. Furthermore, by implementing the proposed strategy, significant improvements are attained in the torque pulsation, speed, and total harmonic distortion of the induction motor. The comparisons are drawn between with and without dead time compensation technique, the former shows significant improvements in all aspects of the power quality parameters and power converters efficiency. Full article

(This article belongs to the Special Issue Advances in Control of Power Electronic Converters)

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