Energies

Research

26 pages, 16874 KiB

Open AccessArticle

Simple Discrete Control of a Single-Phase Voltage Source Inverter in a UPS System for Low Switching Frequency

by Zbigniew Rymarski

Energies 2023, 16(15), 5717; https://doi.org/10.3390/en16155717 - 31 Jul 2023

Cited by 1 | Viewed by 841

Previous research has shown that the inverter output voltage distortions are higher for low switching frequencies, and it is impossible to increase the controller gains because it will cause oscillations of the output voltage. The main reason is the real frequency domain characteristic [...] Read more.

Previous research has shown that the inverter output voltage distortions are higher for low switching frequencies, and it is impossible to increase the controller gains because it will cause oscillations of the output voltage. The main reason is the real frequency domain characteristic of the PWM modulator and measuring traces, which can be modelled as switching periods delays. The thesis of this paper is that by using the control system that takes care of these delays, it is possible to decrease output voltage distortions for the standard loads for relatively low switching frequencies (e.g., 12,800 Hz). The Luenberger observer was implemented in the multi-input-multi-output passivity-based control of the system with the delay, in order to predict the state variables of the inverter. It is shown that state variable prediction is unnecessary for high switching frequencies (e.g., 51,200 Hz). The theory, simulations and breadboard verification, using the inverter model controlled with the real-time interface MicroLabBox, are presented. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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24 pages, 4642 KiB

Open AccessArticle

A Comprehensive Small-Signal Model Formulation and Analysis for the Quasi-Y Impedance-Source Inverter

by Rafael Santos, Marcus V. M. Rodrigues, Luis De Oro Arenas and Flávio A. S. Gonçalves

Energies 2023, 16(13), 4877; https://doi.org/10.3390/en16134877 - 22 Jun 2023

Cited by 1 | Viewed by 1352

Abstract

This paper presents a detailed derivation of the small-signal model and components design considerations for the Quasi-Y-Source inverter. The design methodology is based on the converter steady-state operation, considering the impedance network inductor and capacitor voltage and charge balances, respectively. Moreover, the additional [...] Read more.

This paper presents a detailed derivation of the small-signal model and components design considerations for the Quasi-Y-Source inverter. The design methodology is based on the converter steady-state operation, considering the impedance network inductor and capacitor voltage and charge balances, respectively. Moreover, the additional design criteria for component selection, considering control constraints and performance compromise, are given by parametric variation analysis based on converter dynamic response. The small-signal model and transfer functions are obtained using a state-space averaged model, including converter non-ideal characteristics given by equivalent-series resistances (ESR), which makes possible the proposition of different control strategies, using both single or multi-loop schemes. To demonstrate the usefulness of the proposed small-signal model, a DSP-based single-loop type-II PI control strategy is used in which the peak DC-link voltage is indirectly controlled through the measurement of the impedance network capacitor voltage. The controller and converter performances are verified with simulation and experimental results and successfully confirm the validity of the proposed dynamic model. Finally, the obtained results are validated with a built small-scale three-phase/three-wire inverter prototype. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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15 pages, 6816 KiB

Open AccessArticle

Research on a Modeling and Control Strategy for Interleaved Boost Converters with Coupled Inductors

by Zhuangzhi Dai, Jilong Liu, Kefeng Li, Zhiqin Mai and Guijing Xue

Energies 2023, 16(9), 3810; https://doi.org/10.3390/en16093810 - 28 Apr 2023

Cited by 2 | Viewed by 1705

Abstract

Interleaved DC–DC converters have significant advantages in improving the capability of power converters, and coupling the filtering inductor of the converter could further increase the power density. However, existing modeling and controller designs are complex and require multiple sensors to be involved in [...] Read more.

Interleaved DC–DC converters have significant advantages in improving the capability of power converters, and coupling the filtering inductor of the converter could further increase the power density. However, existing modeling and controller designs are complex and require multiple sensors to be involved in the control, which is not conducive to engineering implementation and reducing production costs. In view of this problem, taking a two-phase interleaved boost converter with a coupled inductor as an example, the small-signal models of the converter are derived for the resistive load and constant voltage source load using the state averaging method. The total inductor current is engaged in the control as a feedback signal, avoiding the coupling effect of the inductor on increasing the complexity of the controller. Based on this, a double closed-loop controller is designed, and a prototype of the two-phase interleaved boost converter with coupled inductor is built. Only one current sensor and one voltage sensor are required to participate in the control. The effectiveness of the analysis and design in this paper are verified by experiments. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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12 pages, 10582 KiB

Open AccessArticle

The Experimentally Measured Influence of the Si-MOSFET Replacement Switches to WBG Transistors in the Voltage Source Inverters as the Source of Radiation Noise

by Krzysztof Bernacki and Zbigniew Rymarski

Energies 2023, 16(2), 870; https://doi.org/10.3390/en16020870 - 12 Jan 2023

Cited by 1 | Viewed by 970

Abstract

The aim of the paper is to present the change in the radiation noise of the single-phase voltage source inverter (VSI) when the Si-MOSFET transistors are replaced by the wide-band-gap (WBG) SiC-MOSFET and GaN transistors. The power spectral density of the near-field interference [...] Read more.

The aim of the paper is to present the change in the radiation noise of the single-phase voltage source inverter (VSI) when the Si-MOSFET transistors are replaced by the wide-band-gap (WBG) SiC-MOSFET and GaN transistors. The power spectral density of the near-field interference is used to visualise the change of the radiation noise of the VSI. The conclusions concern the results of the experimental replacement of the switches to the WBG technology in the existing inverters. Three switching frequencies and two gate circuits were used to show the change in the radiation noise. The measurements of the experimental VSI are presented. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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16 pages, 4554 KiB

Open AccessArticle

Three-Phase Grid-Connected Inverter Power Control under Unbalanced Grid Conditions Using a Time-Domain Symmetrical Components Extraction Method

by Mohammad Alathamneh, Haneen Ghanayem, Xingyu Yang and R. M. Nelms

Energies 2022, 15(19), 6936; https://doi.org/10.3390/en15196936 - 22 Sep 2022

Cited by 3 | Viewed by 2230

Abstract

Presented in this paper is a method of bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid situations. Unbalanced three-phase load and unbalanced grid impedance are illustrations of unbalanced grid issues that have been investigated. As a result, [...] Read more.

Presented in this paper is a method of bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid situations. Unbalanced three-phase load and unbalanced grid impedance are illustrations of unbalanced grid issues that have been investigated. As a result, both grid currents and point-of-common-coupling (PCC) voltages will be unbalanced. The real and reactive power that is delivered to the grid oscillates by a significant amount in these unbalanced conditions. A time-domain symmetrical components extraction approach is used to calculate the inverter’s reference currents from the negative- and zero-sequence components of the measured currents. The suggested approach corrects unbalanced grid currents and unbalanced PCC voltages, and provides the desired real and reactive power to the grid when unbalanced situations exist. As a consequence, power oscillations will be eliminated, and power control will be possible. The suggested method’s performance is supported by simulation, and various experimental results are obtained utilizing the dSPACE DS1202 real-time interface platform. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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22 pages, 6870 KiB

Open AccessArticle

The Effect of Replacing Si-MOSFETs with WBG Transistors on the Control Loop of Voltage Source Inverters

by Krzysztof Bernacki and Zbigniew Rymarski

Energies 2022, 15(15), 5316; https://doi.org/10.3390/en15155316 - 22 Jul 2022

Cited by 4 | Viewed by 1178

Abstract

The operation of a voltage source inverter (VSI) depends on its output LC filter and the PWM modulator delay. The VSI model includes serial equivalent resistance based on the resistances of the active inverter bridge transistors, the filter coil winding, and additional PCB [...] Read more.

The operation of a voltage source inverter (VSI) depends on its output LC filter and the PWM modulator delay. The VSI model includes serial equivalent resistance based on the resistances of the active inverter bridge transistors, the filter coil winding, and additional PCB elements, such as traces and connectors, in addition to the large equivalent resistances that result from power losses in the coil core and switches. These dynamic power losses depend on the switching frequency and the inverter load. This paper investigates the change in equivalent serial resistance that occurs if the standard Si-MOSFET switches are replaced with wide bandgap (WBG) transistors with correspondingly lower equivalent serial resistance. The paper further investigates how such a change influences the design of the controller, given that replacement of the switches shifts the roots of the closed-loop characteristic equation. Theoretical analyses of the influence of equivalent serial resistance for a multi-input single-output passivity-based controller and a single-input single-output coefficient diagram method are also presented. These analyses are applied to both types of switches. Two methods are used to measure the serial equivalent resistance for a given VSI using Si and WBG switches. The possibility of replacing switches with WBG technology in existing inverters was assessed, and the corresponding controller adjustment that would be required. The theoretical analysis is verified via the use of an experimental VSI. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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17 pages, 4169 KiB

Open AccessFeature PaperArticle

Power Electronics Programmable Voltage Source with Reduced Ripple Component of Output Signal Based on Continuous-Time Sigma-Delta Modulator

by Michał Gwóźdź

Energies 2021, 14(20), 6784; https://doi.org/10.3390/en14206784 - 18 Oct 2021

Cited by 1 | Viewed by 1667

Abstract

In this work, an idea of a wideband, precision, power electronics programmable voltage source (PVS) is presented. One of the basic elements of the converter, the control section, contains a continuous-time sigma-delta modulator (SDM) with a pair of interconnected complementary comparators, which represents [...] Read more.

In this work, an idea of a wideband, precision, power electronics programmable voltage source (PVS) is presented. One of the basic elements of the converter, the control section, contains a continuous-time sigma-delta modulator (SDM) with a pair of interconnected complementary comparators, which represents a new approach. In this case, the SDM uses comparators with a dynamic hysteresis loop (DHC) that includes an AC circuit rather than an R-R network. Dynamic hysteresis is a very effective way of eliminating parasitic oscillation during the signal transition at the input of the comparator; it also affects the frequency characteristics and, especially, the phase properties of the comparator, and this phenomenon is exploited in the proposed converter. The main disadvantage of all pulse-modulated converters is the presence of a ripple component in the output voltage (current), which reduces the quality of the output signal and may cause high-frequency disturbances. A basic feature of PVS is a lower RMS value for the pulse modulation component in the output voltage of the converter, compared to the typical value. Another important feature of the proposed converter is the ability of precise mapping of the output voltage to the reference (input) signal. The structure of the control circuit is relatively simple—no complex, digital components are used. Due to the high frequency of the SDM output bit-stream, the simulation model of the power stage of PVS is based on the power modules with gallium-nitride field effect transistors (GaN FETs). The work discusses the rules of PVS operations and the results from PVS simulation model studies as well as highlights the possible application fields for systems with a PVS. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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28 pages, 3103 KiB

Open AccessArticle

Effect of the Heat Dissipation System on Hard-Switching GaN-Based Power Converters for Energy Conversion

by David Lumbreras, Manel Vilella, Jordi Zaragoza, Néstor Berbel, Josep Jordà and Alfonso Collado

Energies 2021, 14(19), 6287; https://doi.org/10.3390/en14196287 - 02 Oct 2021

Cited by 6 | Viewed by 2813

Abstract

The design of a cooling system is critical in power converters based on wide-bandgap (WBG) semiconductors. The use of gallium nitride enhancement-mode high-electron-mobility transistors (GaN e-HEMTs) is particularly challenging due to their small size and high power capability. In this paper, we model, [...] Read more.

The design of a cooling system is critical in power converters based on wide-bandgap (WBG) semiconductors. The use of gallium nitride enhancement-mode high-electron-mobility transistors (GaN e-HEMTs) is particularly challenging due to their small size and high power capability. In this paper, we model, study and compare the different heat dissipation systems proposed for high power density GaN-based power converters. Two dissipation systems are analysed in detail: bottom-side dissipation using thermal vias and top-side dissipation using different thermal interface materials. The effectiveness of both dissipation techniques is analysed using MATLAB/Simulink and PLECS. Furthermore, the impact of the dissipation system on the parasitic elements of the converter is studied using advanced design systems (ADS). The experimental results of the GaN-based converters show the effectiveness of the analysed heat dissipation systems and how top-side cooled converters have the lowest parasitic inductance among the studied power converters. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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Graphical abstract

15 pages, 3706 KiB

Open AccessArticle

Robust Sliding Mode Control of a Unipolar Power Inverter

by Muhammad Awais, Abdul Rehman Yasin, Mudassar Riaz, Bilal Saqib, Saba Zia and Amina Yasin

Energies 2021, 14(17), 5405; https://doi.org/10.3390/en14175405 - 31 Aug 2021

Cited by 6 | Viewed by 2150

Abstract

The key issue in the practical implementation of the sliding mode (SM) control–based power inverter is the variable switching frequency. This variable switching frequency not only induces electromagnetic interference (EMI) noise, but also reduces the efficiency of the inverter, as the size of [...] Read more.

The key issue in the practical implementation of the sliding mode (SM) control–based power inverter is the variable switching frequency. This variable switching frequency not only induces electromagnetic interference (EMI) noise, but also reduces the efficiency of the inverter, as the size of the inductor and capacitor does not alter in tandem with this variable frequency. In this context, fixed switching frequency–based SM control techniques are proposed; however, some of them are too complex, while others compromise the inherent properties of SM control. In this research, a fixed frequency SM controller is proposed, which is based on the novel low-pass filter extraction of the discontinuous control signal. This allows the technique to be implemented with fewer hardware components, thus reducing the complications of implementation, while maintaining the robustness and parametric invariance of SM control. A simulation-based comparison with an existing pulse width modulated (PWM) SM controller is presented as the benchmark. In comparison with the sigmoid function SM controller, an improvement of 50% in the settling time along with zero steady-state errors and a further 37% and 42% improvement in the undershoot and overshoot, respectively, is reported in the simulation. A hardware setup is established to validate the proposed technique, which substantiates the simulation results and its disturbance rejection properties. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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12 pages, 3235 KiB

Open AccessArticle

Wideband Modeling of DC-DC Buck Converter with GaN Transistors

by Piotr Musznicki, Pawel B. Derkacz and Piotr J. Chrzan

Energies 2021, 14(15), 4430; https://doi.org/10.3390/en14154430 - 22 Jul 2021

Cited by 2 | Viewed by 1745

Abstract

The general wideband modeling method of the power converter is presented on the example of DC-DC buck converter with GaN High Electron Mobility Transistors (HEMT). The models of all basic and parasitic components are briefly described. The two methods of Printed Circuit Board [...] Read more.

The general wideband modeling method of the power converter is presented on the example of DC-DC buck converter with GaN High Electron Mobility Transistors (HEMT). The models of all basic and parasitic components are briefly described. The two methods of Printed Circuit Board (PCB) layout parameter extraction are presented. The results of simulation in Saber@Sketch simulation software and measurements are compared. Next, the model of the converter is reduced to obtain one lumped inductance of the input filter PCB for the analytical prediction of transistor turn-off ringing frequency and overvoltage. The practical use of the model is presented for sizing optimal capacitance of snubber. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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22 pages, 7301 KiB

Open AccessArticle

Novel Single-Phase Grid-Tied NPC Five-Level Converter with an Inherent DC-Link Voltage Balancing Strategy for Power Quality Improvement

by Jorge Lara, Lesedi Masisi, Concepcion Hernandez, Marco A. Arjona and Ambrish Chandra

Energies 2021, 14(9), 2644; https://doi.org/10.3390/en14092644 - 05 May 2021

Cited by 4 | Viewed by 2219

Abstract

This paper presents a novel single-phase grid-tied neutral-point-clamped (NPC) five-level converter (SPFLC). Unlike the literature on five-level NPC topologies, the proposed one is capable of inherently balancing the voltage of the DC-link split capacitors. For this purpose, a simple Multicarrier Phase Disposition (MPD) [...] Read more.

This paper presents a novel single-phase grid-tied neutral-point-clamped (NPC) five-level converter (SPFLC). Unlike the literature on five-level NPC topologies, the proposed one is capable of inherently balancing the voltage of the DC-link split capacitors. For this purpose, a simple Multicarrier Phase Disposition (MPD) Pulse Width Modulation (PWM) technique is used, thus avoiding both complex modifications to the Space Vector Modulation (SVM) and offset voltage injections into the carrier based (CB) PWM, as commonly done in most conventional balancing algorithms. Bearing in mind that the proposed balancing strategy only requires measuring the capacitors’ voltages and the sign of the converter output current, it has a very low complexity. The developed strategy is not only straightforwardly implemented but is also very effective for obtaining symmetrical and undistorted voltage levels from the proposed multilevel converter, as well as for significantly improving the power quality of the SPFLC output voltage and, in turn, of the grid current. The simulation results obtained with MATLAB-SimPowerSystems as well as the experimental results obtained with the prototype built in the laboratory validate the topology of the proposed NPC five-level converter and the voltage balancing strategy, by showing a good performance under step-changes and exhaustive operating test conditions. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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12 pages, 4075 KiB

Open AccessArticle

Modified SPWM Technique with Zero-Sequence Voltage Injection for a Five-Phase, Three-Level NPC Inverter

by Charles Odeh, Dmytro Kondratenko, Arkadiusz Lewicki and Andrzej Jąderko

Energies 2021, 14(4), 1198; https://doi.org/10.3390/en14041198 - 23 Feb 2021

Cited by 5 | Viewed by 2620

Abstract

This article presents a modified sinusoidal pulse-width modulation (SPWM) scheme for a five-phase, three-level neutral-point-clamped inverter. The modulation scheme deploys a modified min–max function to inject the zero-sequence components into the reference modulating signals; hence enabling the effective utilization of the DC-link voltage. [...] Read more.

This article presents a modified sinusoidal pulse-width modulation (SPWM) scheme for a five-phase, three-level neutral-point-clamped inverter. The modulation scheme deploys a modified min–max function to inject the zero-sequence components into the reference modulating signals; hence enabling the effective utilization of the DC-link voltage. Balanced split-input DC-link voltages were achieved through further incorporation of adjustable voltage-dependent variables into the reference signals. The dynamic performance of the control approach is demonstrated through simulations and experiments on a laboratory inverter prototype; the results are well presented. Full article

(This article belongs to the Special Issue Control and Modeling of Power Converters and Inverters)

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