Impedance Source Network Research Articles

A comprehensive review of impedance source network DC circuit breaker topologies

A comprehensive review of impedance source network DC circuit breaker topologies

Direct single‐phase isolated improved gamma Z‐source AC–AC converter suitable for DVR application

AbstractA direct single‐phase isolated improved gamma Z‐source AC–AC converter is designed and manufactured in proposed paper. This converter contains an impedance source structure and its advantages. In general, these advantages are as follows. Firstly, the proposed structure has a wide range of output voltage as boost and buck as well as in‐phase or out‐of‐phase states. Secondly, the proposed converter is electrically isolated thanks to a high frequency transformer (HFT), which significantly reduces the volume of the structure; therefore, in applications such as dynamic voltage restorer (DVR), there is no need to install a coupling transformer with the grid frequency which is very bulky and full of losses. Furthermore, the HFT of the proposed converter is a three winding transformer which also acts as the inductance needed for impedance source network. In addition, the safe commutation method has been utilized, which reduces the voltage spikes on the power switches. Finally, the analysis and design of this converter has been done, and then confirmed by a small‐scale laboratory prototype.

High-Performance Voltage-Boost Switched-Coupled-Inductor DC–DC Converters Deduced From Impedance Source Networks

High-Performance Voltage-Boost Switched-Coupled-Inductor DC–DC Converters Deduced From Impedance Source Networks

New Multicell Switched-Inductor Quasi-Z-Source Inverter

To address the problems of quasi-Z-source inverters with limited boosting ability and high voltage stress, a novel class of multicell switched-inductor quasi-Z-source inverters is proposed. The new inverter is based on the quasi-Z-source inverter in which the inductors in the impedance source network are replaced by a multicell switched-inductors. In this paper, a detailed description of the topology and operating principle of the new inverter is first made. Then, a deep comparison of the proposed topology with the existing topologies is performed by selecting the appropriate number of switched-inductor units. Finally, to verify the feasibility and superiority of the proposed new topology, a great number of simulations and experiments are conducted. The results demonstrate that, compared to the original quasi-Z-source inverter and existing modified topologies, the boosting capacity of the proposed new inverter increases significantly with the number of cascaded switched-inductor units, and its voltage stress across the capacitors and current ripple through the inductors are effectively reduced.

An DPWM for Active DC-Link Type Quasi-Z-Source Inverter to Reduce Component Voltage Rating

The conventional DC-link type quasi-Z-source inverter has been known as a buck–boost inverter with a low component voltage rating. This paper proposes an active DC-link type quasi-Z-source inverter by adding one active switch and one diode to the impedance-source network to enhance the voltage gain of the inverter. As a result, the component voltage rating of the inverter is significantly reduced, which is demonstrated through some comparisons between the proposed topology and others. A discontinuous pulse width modulation (DPWM) scheme is proposed to control the inverter, which reduces the number of commutations compared to the traditional strategy. Under this approach, the insertion of a shoot-through state does not cause any extra commutations compared to the conventional voltage-source inverter. Details about control implementation, steady-state analysis, and design guidelines are also presented in this paper. Simulation and a laboratory prototype have been built to test the proposed inverter. Both buck and boost operations of the proposed inverter are implemented to validate the performance of the inverter.

A Topological Advancement Review of Magnetically Coupled Impedance Source Network Configurations

Magnetically coupled impedance source networks provide a wide range of applications, such as dc to dc, dc to ac, ac to ac, ac to dc unidirectional or bi-directional power conversion. Various impedance source networks are reported in the literature to overcome the barriers of conventional voltage source inverters. They offer high boost with buck-boost capabilities and reduce power conversion stages. Thus, they provide an economical solution to expanding power systems, and are most suitable for renewable sources having low output. The goal of this study is to provide an in-depth comprehensive review of the major topologies of magnetically coupled impedance source networks. The review is more focused towards the fast-growing niche area, which has seen many advancements in the last few years. Best efforts are made to include relevant major topological advancements, with the aim of providing relevant and accessible information for researchers. This research provides a detailed comparison of essential factors and presents a full assessment of major topological improvements in MCIS networks.

Modelling and performance evaluation of diode‐assisted impedance source networks

This paper deals with a family of two- and three-windings coupled inductor-based impedance source networks. They have been basically derived from the successful quasi-Y-source network (q-YSN) by replacing one of its capacitors with a diode with different combinations of coupled inductors and called diode assisted impedance source networks (DA-ISNs). The general three-windings version, called diode-assisted Y-source network (DA-YSN), as the origin of all other simplified versions, is thoroughly investigated from various points of view. From the voltage gain characteristics aspect, it offers a higher voltage gain with the same number of elements as the conventional q-YSN. Lower magnetizing and input current ripples show the higher power density of DA-YSN in comparison to q-YSN. The effectively reduced voltage stress and the total value of capacitors, and a considerable decreased conversion loss of the magnetic element are the other attractive features of DA-YSN. With the advantages of a low input current ripple and a high voltage gain, DA-ISNs can be suitable choices for renewable energy and distributed power generation systems. Operating principle, circuit analysis, and parameters design guidelines for DA-YSN are thoroughly investigated. Also, the small-signal modelling, analysis and the controller design are presented in this paper. Finally, the theoretical properties of DA-YSN are scrutinized by performing extensive experiments on a 200 W laboratory prototype.

Performance Validation of PV System Incorporated ZSI-Dynamic Voltage Restorer for Long-Lasting Power Quality Improvement

Abstract A power distribution system’s main challenge is to provide consistent, reliable electricity to fulfill high demand. The incorporation of renewable energy sources into the utility grid system can be accomplished. However, renewable sources are intermittent in nature, and the loads work dynamically and cause imbalances to the system voltage within an immediate time frame. Intermittent renewable sources affect the voltage of the power grid system. Photovoltaic (PV) power generation with Z-source inverter (ZSI)–based dynamic voltage restorer (DVR) is used to avoid negative effects on the voltage. For step-up low direct current (dc) voltage to require alternating current voltage for the compensation of the voltage disturbance, ZSI with an energy storage impedance network is used. dc-dc converters connect the PV cell and the battery storage to the impedance source network. This article also incorporates an improved second-order generalized integrator (I-SOGI) control system for the generation of reference voltage signals. The I-SOGI control reference voltage generation approach greatly improves system performance and decreases the harmonic voltage. The voltage-related problems in the system connected to the utility grid are mitigated with DVR. In different load and source conditions, the PV generation with DVR performance is verified by the experimental prototype.

Quasi-Y Source network: A design and analysis approach for a DC-DC application

This paper presents a detailed design methodology for a DC-DC converter based on the recent Quasi-Y Source impedance network, which has interesting characteristics for applications related to renewable energy sources. Despite the advantages of this particular impedance network, there is a lack in the current literature, of details regarding the design of the diode and coupled inductors, and a description of its leakage inductance impact on the performance of the Quasi-Y-Source based converter. Therefore, this work presents design guidelines for the coupled inductors including core material choice criteria and optimization of windings combinations. Several analyses are conducted, through computational simulation, with respect to voltage stresses on the converter switches. The simulations results are compared with experimental implementation considering different voltage gain B operational scenarios. The obtained results shows that the proposed approach is useful to design: (a) Quasi-Y Source DC-DC converter components; (b) Evaluate the best coupled inductors configuration; (c) Implement closed loop controllers and snubbers circuits. A discussion evaluating the converter characteristics is made, exploring possible solutions to problems related to real operation scenarios.

Solar Photovoltaic Interfaced Quasi Impedance Source Network Based Static Compensator for Voltage and Frequency Control in the Wind Energy System

In this paper, the purpose of improving the power quality of the standalone wind conversion system (WECS) is to utilize a quasi-impedance (qZ) static compensator (STATCOM) integrated solar photovoltaic (SPV) source network. The standalone WECS has utilized the flywheel energy storage system (FESS) and the self-excited induction generator (SEIG). The SPV power generation network integrates with the STATCOM DC-Link to compensate for the voltage and frequency fluctuations over a longer time. The SEIG terminal voltage and STATCOM DC-link voltage are regulated using an enhanced second-order generalized integrator (ESOGI) with a fuzzy logic controller (FLC). The coordination logic is proposed in order to handle the various scenarios and make the device energy efficient. The unit is built for optimal usage of the electrical energy generated from renewable sources by utilizing physical energy storage systems such as flywheel and battery. In both batteries and flywheels, excess power from the SPV and wind turbines is collected. To verify the performance of the SPV supported STATCOM, the simulation and experimental studies are performed under specific load conditions. This paper describes an optimal way to produce and utilize green power with better energy efficiency. With various current conditions, the typical level of harmonic distortion of the source current is about 1.4% lower than that specified by IEEE Std. 519–2014 for the tolerable 5% level.

Fault-tolerant analysis of two boost inverters for open-end winding induction motor drives

An open-end winding induction motor drive system fed by two boost inverters with fault-tolerant capability is presented to improve the reliability and safety of the drive system. The boost inverters consist of an impedance-source network and a two-level inverter. It can realize the boost/buck function. An analysis of its fault-tolerance is presented in detail. Short circuits and open circuits are commonly considered as the two main types of faults. Therefore, the fault types of the dual boost inverters are analyzed and diagnosed. Then, two different fault-tolerant schemes are presented. The presented fault-tolerant inverters are restructured through the power switch itself. In addition, different SVPWM methods are addressed. A simulation model and an experimental platform are constructed. Simulation and experimental results verify the fault tolerance of the drive system.

A Simple Space Vector Modulation Method With DC-Link Voltage Balancing and Reduced Common-Mode Voltage Strategy for a Three-Level T-Type Quasi-Z Source Inverter

Single-stage converters based on an impedance source (IS) network merged with a multilevel inverter remain a trending research topic, from both the topological and control perspectives, because of their potential in applications involving renewable energy. This paper presents a new, simplified space vector pulse-width modulation (SVPWM) for a three-phase three-level T-type quasi-impedance source inverter (3L-T-type qZSI). The benefits of the proposed modulation strategy include functionalities, such as boosting the input voltage and controlling the neutral-point (NP) voltage using the redundant small vectors, to mitigate the inner capacitors voltages imbalance. The proposed SVPWM guarantees a minimum common-mode voltage while preserving a very simple implementation, thus reducing the complex computations and cascaded proportional-integral (PI) control loops of the conventional SVPWM methods. The proposed algorithm can be applied to different multilevel inverter configurations combined with an IS network. A comprehensive simulation study and experimental results demonstrated the good performance of the proposed control method for dynamic response and imbalance conditions.

Effects of Parasitic Resistances on Π-Source Impedance Network

Magnetically coupled impedance-source networks are often connected with voltage source inverter to obtain a higher voltage gain and achieve less shoot-through duty ratio occupation. Among them, $\Pi $ -source impedance source network was proposed to achieve higher voltage gain, lower current stress, smaller core size, and also smaller circulating current when compared with the conventional $\Delta $ -source inverter, but it still faces the problem of the voltage gain reduction caused by the parasitic resistances. The parasitic resistance effect becomes more serious by the high operating current nature of magnetically coupled impedance-source networks. Therefore, in this paper, the effect of parasitic resistances on $\Pi $ -source impedance network is investigated by modeling the $\Pi $ -source converter with parasitic resistances consideration. Based on this, the voltage gain is firstly deduced and analyzed. Then, the characteristic of the voltage gain is researched under different shoot-through duty ratios, different winding ratios, and different resistances ratios. Different from the ideal lossless case, the voltage gain increases first and then decreases when the shoot-through duty ratio becomes larger. Finally, the correctness of the deduction and analysis in this paper is verified by corresponding simulation and experimental results.

A new enhanced‐boost switched‐capacitor quasi Z‐source network

This paper proposes a new enhanced-boost non-transformer-based impedance source network. The strong boosting ability of the proposed topology is realized by making use of the switched capacitor concept in the formerly introduced enhanced-boost quasi Z-source network (EB-qZSN) without any additional active switch. Meanwhile, the advantages of the EB-qZSN such as input current continuity and shared ground between the input and the output are maintained. In addition to the lower shoot-through requirement to obtain high voltage gains, the proposed impedance network takes advantage of a smaller size of passive components along with a lower input current ripple to achieve higher power density and higher efficiency. Moreover, the lower total rating of the switching elements, defined by switching device power, directly translates to lower cost for the proposed method. The operation principles and the design guideline of components are explained in detail and a thorough comparison with other ZSN is presented. A 240W DC–DC prototype converter was built to validate the performance principles and properties of the proposed impedance network.

An Impedance Source Multi-Level Three Phase Inverter with Common Mode Voltage Elimination and Dead Time Compensation

Currently, most electro-mechanical drive systems that require speed control use pulse-width modulated (PWM) variable frequency drives known as adjustable speed drives (ASD). The high switching speeds of the electronics switches are essential for proper operation of the ASD. Common mode voltage (CMV) has its origin in the PWM switching. The CMV increases the stress on the coils and windings, reduces the life of the bearing and, therefore, has a significant impact on motor life cycle. In this paper, a variant of a PWM-based space vector modulation (SVPWM) switching algorithm is proposed to control both the shoot-through intervals and the dead time of the power switches that could be compensated. The proposed algorithm is implemented on a platform consisting of an impedance source network in the DC side of the topology with the purpose of mitigating the CMV and capability of voltage boosting. Since similar methods have achieved a CMV reduction of 1/6 of the DC link voltage so far, in this paper, while surpassing the disturbing current harmonics, the high efficiency is fully accessible. The presented experimental results verify the effectiveness of the proposed approach by slightly increasing the total harmonic distortion (THD) and reducing the converter losses.

A Review of the Power Converter Interfaces for Switched Reluctance Machines

The use of power electronic converters is essential for the operation of Switched Reluctance Machines (SRMs). Many topologies and structures have been developed over the last years considering several specific applications for this kind of machine, improving the control strategies, performance range, fault-tolerant operation, among other aspects. Thus, due to the great importance of power electronic converters in such applications, this paper is focused on a detailed review of main structures and topologies for SRM drives. The proposed study is not limited to the classic two-level power converters topologies dedicated to the SRMs; it also presents a review about recent approaches, such as multilevel topologies and based on impedance source network. Moreover, this review is also focused on a new class of topologies associated to these machines, namely the ones with fault-tolerant capability. This new category of topologies has been a topic of research in recent years, being currently considered an area of great interest for future research work. An analysis, taking into consideration the main features of each structure and topology, was addressed in this review. A classification and comparison of the several structures and topologies for each kind of converter, considering modularity, boost capability, number of necessary switches and phases, integration in the machine design, control complexity, available voltage levels and fault-tolerant capability to different failure modes, is also presented. In this way, this review also includes a description of the presented solutions taking into consideration the reliability of the SRM drive.

Implementation of solar PV system unified ZSI-based dynamic voltage restorer with U-SOGI control scheme for power quality improvement

The main challenge in today's power system is to supply continuous, reliable power and satisfy the high demand. The incorporation of renewable energy sources into the utility grid system can be accomplished. However, the renewable sources are intermittent in nature and the loads work dynamically and cause imbalances to the system voltage within an immediate time. Intermittent renewable sources affect the voltage of the power grid system. Photovoltaic (PV) power generation with Z-source inverter (ZSI)-based dynamic voltage restorer (DVR) is used to avoid that. For step-up low DC voltage to required AC voltage for the compensation of the voltage disturbance, ZSI with the energy storage impedance network is used. DC-DC converters connect the PV cell and the battery storage to the impedance source network. This article also incorporates an upgraded second-order generalized integrator (U-SOGI) control system for the generation of reference voltage signals. The U-SOGI control reference voltage generation approach greatly improves system performance and decreases the harmonic voltage. The voltage-related problems in the system connected to the utility grid are mitigated with DVR. In different load and source conditions, the PV generation with DVR performance is verified by the digital simulation and experimental prototype.

Design and Analysis of High Gain Quasi Y - Source Impedance Network

In this paper, performance of a high gain quasi Y-source impedance network converter is analysed. This converter has a high voltage gain while using a small duty ratio. Compared to other impedance source converters, Y-source converter operates with lower shoot-through duty cycle for the same boosting gain. To achieve that, a three windings transformer with very low leakage inductance is employed. In turn, the switching losses and heating are low at the same boosting gain. Moreover, in this type of converter, the boosting gain depends on number of variables, and hence more degrees of freedom for meeting design constraints. The voltage and current of the switching elements are analysed during shoot and non-shoot through. The analysis shows that for high boosting gain some components have high voltage stress compared to conventional converters. Moreover, fast switching diodes are required to achieve high boosting gain. The performance of the proposed converter is analysed using numerical simulation and experimental testing.

Impedance Source-based Multilevel Inverter: A State-of-the-Art Review

Impedance source-based multilevel inverters are becoming popular for emerging power generation technologies such as fuel cells, photovoltaic, and wind turbines. It is one of the most promising power electronic interfaces for single stage DC/AC conversion with inherent buck-boost capability. Therefore, in this paper, an extensive review of emerging impedance source-based multilevel inverter (Z-MLI) topologies is presented. These topologies are developed by the combination of impedance source network and multilevel inverter (MLI) with the merits of high voltage gain, enhanced reliability due to shoot-through immunity, improved input voltage regulation, reduced filter size, and better quality of supply. Most of the recent Z-MLI topologies are based on quasi-Z-source network which operates with continuous input current. In order to identify a suitable topology, an exhaustive comparison is made with various configurations of Z-MLIs in terms of component count, boost gain, switching stress, and control complexity.

Effects of Parasitic Resistances on Magnetically Coupled Impedance-Source Networks

Magnetically coupled impedance-source networks can achieve a higher voltage gain with smaller shoot-through duty ratio in comparison with the conventional impedance-source networks without coupled inductors. However, the practical voltage gain is seriously affected by the parasitic resistances in passive components and power devices, which is necessary to be investigated. This article derives and analyzes the effects of parasitic resistances on the voltage gain of magnetically coupled impedance-source networks under three different scenarios: first, different resistance ratio between parasitic resistances and output equivalent resistance, second, different shoot-through duty ratio, and third, different winding ratio. First of all, a generalized equivalent circuit model considering parasitic resistances for the three typical magnetically coupled impedance-source networks—Trans-Z-source, Г-source, and Y-source networks are proposed. Based on it, the effects of parasitic resistances on the voltage gain is mathematically derived and discussed under the aforementioned three different scenarios. And the maximum voltage gain under the consideration of the three resistance ratios simultaneously is also derived. Finally, representative simulation and experimental results are provided to verify the proposed generalized equivalent circuit models, the corresponding mathematical derivations, and the effects of the parasitic resistances on the magnetically coupled impedance-source networks.