Switched Inductor Z-source Inverter Research Articles

Performance Evaluation of Various Z-Source Inverter Topologies for PV Applications Using AI-Based MPPT Techniques

Recent research has been focussed on renewable energy due to the rising need for electrical energy. Renewable energy has a low environmental impact compared to other energy sources. As a result, renewable energy sources (RESs) are the best option for generating electricity. Solar photovoltaic is one of the largest renewable power generators. Solar photovoltaic (PV) is connected to the load via power electronic converters. Most PV installations need a two-stage conversion process consisting of a boost converter to increase the load voltage and an AC-to-DC voltage source inverter to power the load. The Z-source inverter (ZSI) can confront the shortcomings of VSI and two-stage conversions. ZSI connects the PV system to the load and is used to increase the system’s performance. This paper discusses the performance of various topologies of ZSI, such as traditional Z-source inverters (XZSIs); for integrating a PV source into a load, switched inductor Z-source inverters (SIZSIs) and transient Z-source inverters (TZSIs) are used. Also, artificial neural networks (ANNs), fuzzy logic controller (FLC), and adaptive neuro-fuzzy inference system (ANFIS)-based MPPT techniques are discussed for obtaining maximum power from PV panels. Based on the maximum power, the shoot-through duty ratio has been adjusted.

Switched Inductor Z Source Inverters for High Boost Applications

Abstract—This paper analyses a different configuration for the classical Z-Source Inverters (ZSI) which is named as Switched Inductor Z-Source Inverters (SL-ZSI) through simulation results. This configuration uses a unique impedance network that helps in the voltage adjustability. Comparing with the ordinary Z-source inverter, the new configuration provides more voltage inversion ability and enhances the output power quality of the main circuit considerably. The various applications of this configuration include DC-AC, AC-AC, DC-DC and AC-DC power conversions. Index Terms—Inverter, voltage source inverter (VSI), Z-source inverter (ZSI), switched inductor Z-source inverter (SI-ZSI)

A Quasi-Z-Source Inverter with a Network Capacitor-Inductor

In this research, a new Z-source inverter inspired by the quasi-inductor-switched Z-source inverter is presented. The new inverter has an acceptable boost factor, and gain voltage compared to the similar Z-source inverter. Also, in this new topology, the capacitors’ voltage stress has been decreased compared to similar inverters. In this converter, a capacitor is replaced with the side diodes of the quasi-Z-source inverter. The input current in this inverter is continuous and it is a low figure that at the moment of switching off about 54 A (V in = 120 V). The high inrush current damages the converter components. The operation of this inverter has been checked in different modes and the voltage and current equations of all elements have been calculated. The new converter can be extended to n-cascade, and it makes to achieve a higher boost factor with a low-duty cycle. The ingredients used in the new topology are fewer than those of the switched-inductor Z-source inverter. The analysis and extraction of all voltage stress such as capacitors, diodes, switches, all currents such as inductors, dc-link average, inrush current, voltage gain and boost factor of the new topology have been done and compared with other structures. The DC-link voltage (Vi ) is 148 V with an input voltage of 120, so the boost factor is 1.43.

Switched Inductor Z-Source Inverter with Modified Space Vector Pulse Width Modulation for Uninterruptible Power Supply

This paper implies the modified space vector pulse width modulation for switched inductor z-source inverter-based uninterrupted power supply. In a conventional inverter-based uninterrupted power supply system, efficiency is reduced because of additional devices. The output voltage of the proposed switched inductor z-source inverter with modified space vector pulse width modulation will be increased by using the boost factor concept, which is not possible in conventional inverters. This inverter has a shoot-through operating state along with the active state and zero state; hence, voltage boost capability is raised. The shoot-through pulses are uniformly allocated within the zero state in each phase in order to increase the output voltage. Hence, voltage due to zero state is condensed in order to generate shoot-through state and the active states remain the same. Theoretical results for the proposed uninterrupted power supply based on switched inductor z-source inverter with modified space vector pulse width modulation technique are verified and validated by using MATLAB/Simulink software.

Improved Switched-Capacitor Switched-Inductor Z-source Inverter for Increasing Boost Factor and Decreasing Voltage Capacitors Stress

ABSTRACT In this paper, the concept of one switched-inductor Z-source inverter is extended to improved switched-capacitor inductor ZSI. In the proposed inverter, capacitors are used instead of the side diodes of the one switched inductor Z-source inverter. The proposed inverter improved voltage gain and boost factor compared to the switched-inductor Z-source inverter and the switched-inductor quasi Z-source inverter. The improved switched-inductor-capacitor Z-source inverter reduces the stress to capacitor voltage. The proposed inverter in this paper can be extended up to the n cascade, thus achieving a higher boost factor of a low duty cycle. The performance of the proposed structure at different operating modes is investigated, and the voltage equations are calculated. The analysis, derivation of the stress of switches voltage, the stress of capacitors voltage, the stress of diode voltage, the stress of inductor current, the gain of voltage, and the boost factor of the proposed inverters are carried out are compared with the similar inverters. To confirm the performance of the proposed converter, a laboratory sample of converters is made, in which, with output for the improved switched-capacitor-inductor ZSI of converter, the DC-link (Vi) voltage is 200 with boost factor 1.67, which confirms the relationships obtained from the proposed converters.

Extended Boost Switched-Embedded-Capacitor-Inductor ZSI with Low Voltage Stress on Capacitors and Soft-Start Capability

ABSTRACT In the present article, the boost factor of the Z-source inverter is noticeably increased by using the switched-inductor structure. The proposed inverter is based on the switched-inductor Z-source inverter which has two series diodes in its switched-inductor. In the proposed ZSI instead of these two series diodes, two capacitors are used. In comparison with the conventional structure, in the smaller duty cycle ratio the proposed structures generate higher voltage. Besides, in the second proposed structure to reduce the voltages on the capacitors of the Z-source network, a dc source is placed between the inverter bridge and the Z-source network. The dc source and the inverter have common ground in both the proposed structures. The conventional and proposed inverters are thoroughly investigated to find out their governing relations, then, the boost factor and voltage across capacitors in both proposed and conventional inverters are compared with each other by simulating them in PSCAD/EMTDC. Next, the prototypes of the proposed inverters with 25 V dc input voltage are used to evaluate the obtained results.

Switched‐capacitor inductor Z‐source inverter with an impedance network

The Z-source inverter was introduced to overcome shortcomings of voltage source inverter and current source inverter. In this paper, the concept of one switched-inductor Z-source inverter is extended to switched-capacitor inductor ZSI with an impedance network. In the proposed inverter, capacitors are used instead of the side diodes of the one switched inductor Z-source inverter. The proposed inverter has a higher boost factor compared to One SL-ZSI and quasi-ZSI. Also, it has lower voltage stress compared to similar inverters. The proposed inverter can be extended to n cases in cascade form. The components used in the proposed topology are lower than the SL-ZSI. The analysis, derivation of boost factor, capacitor voltages, diode voltages, and switch voltages stress of the proposed inverter topology are carried out and are compared with the similar inverters. The advantages of the proposed structure are verified through simulation and implementation. The simulation is performed in MATLAB/SIMULINK.

Switched‐coupled‐inductor Z‐source inverter with a high boost inversion capability

A novel converter with a three-winding coupled inductor, called switched-coupled-inductor Z-source inverter (SCI-ZSI), is developed based on the switched-and-coupled inductor technology in this study. Compared with the conventional switched-inductor Z-source inverter and trans-Z-source inverter, the novel inverter had a higher voltage-boosting capability. In addition, the improved topology shared a common ground point between the DC source and the inverter bridge. Under the same modulation index and load conditions, the input diode and capacitor voltage stress of the proposed inverter were lower than those of the other topologies. The operating principles, impedance-network design, voltage and current stress are presented. The theoretical findings were verified by simulation and experimental results.

Series-type switched-inductor Z-source inverter

To solve the disadvantages of the traditional Z-source inverter (ZSI), this paper investigates a series-type switched-inductor Z-source inverter (SSI-ZSI) topology. It not only preserves the advantages of the traditional ZSI, but also improves the voltage gain. On the condition of the same voltage gain, the capacitor voltage stress is reduced, the soft start characteristic can be achieved and the inverter can be immune to the damage of the inrush current. The circuit structure and operating principle are analyzed in detail; the simulation model and the experimental platform are built. The simulation and experimental results verify the rationality and superiority of the circuit topology.

Analytical comparison and implementation of different inverter topologies for three-phase on-line uninterruptible power supply

Uninterruptible Power Supply (UPS) is a power electronics based system that provides continuous electric power supply to critical equipments when input power fails. For the better performance of UPS when compared with traditional UPS, this paper presents the Z-Source Inverter (ZSI), T-Source Inverter (TSI) and Switched Inductor Z-Source Inverter (SLZSI). The three Pulse Width Modulation (PWM) control techniques like Simple Boost (SB), Maximum Boost (MB) and Third Harmonic Injected Maximum Constant Boost (THIMCB) PWM control are incorporated and compared for the performance analysis of UPS systems by MATLAB/SIMULINK. From the simulation results, it is found that the UPS with SLZSI under THIMCB PWM control is found superior when compared with the UPS with ZSI and TSI. An experimental setup has been developed for the proposed UPS with SLZSI by implementing the THIMCB PWM control algorithm and measurements were taken to validate the theoretical and simulation results.

Analysis of Steady-State Characteristics for a Newly Designed High Voltage Gain Switched Inductor Z-Source Inverter

This paper aims to develop a new switched inductor assisted strong boost Z-source inverter (SL-SBZSI) topology with high voltage gain and analyze the steady-state characteristics of the proposed topology. In the proposed topology, two switched inductors are used within the series impedance structure of the Z-source inverter (ZSI) in order to achieve the high voltage gain. The steady-state characteristics of the proposed topology are analyzed to disseminate its several advantages as compared to traditional ZSIs. The key advantages include the higher boost factor with lower shoot-through duty ratio and lower voltage stresses on capacitors as well as on switches of the inverter bridge. Furthermore, the proposed topology has the soft-start ability which significantly reduces the inrush start-up current while comparing with the traditional ZSI. In the proposed topology, a common ground is shared between the output AC voltage and the input DC voltage source which categorizes this topology to the doubly grounded inverter. The characteristics of the proposed SL-SBZSI are analyzed by considering two operating condition where the simple boost pulse width modulation (PWM) scheme is used to extract the shoot-through pulses. The characteristics of the proposed topology are also compared with different existing topologies along with the conventional modified capacitor assisted Z-source inverter (MCA-ZSI), whose boost factor is much closer to the proposed topology. Rigorous mathematical analyses are presented to clearly demonstrate the benefits of the proposed topology while simulation studies are carried out to demonstrate its distinct features as compared to the existing topology. Finally, experimental studies are conducted to further validate the theoretical and simulation results.

Single‐phase high‐voltage gain switched LC Z‐source inverters

Recently, switched-inductor Z-source inverters (SL-ZSIs) have been reported to achieve high-voltage gain and good power inversion operation at low shoot-through duty ratio D as compared to conventional ZSI. As the SL-ZSIs have high passive component count, weight, volume and losses of the system increases that lead to reduction in efficiency. To address the issues of conventional ZSI and SL-ZSIs, two single-phase switched LC (SLC)-ZSIs (Type 1 SLC-ZSI and Type 2 SLC-ZSI) are proposed in this study to achieve high-voltage gains at low values of D with lower passive component count as compared to SL-ZSIs. At low values of D , modulation index M approaches to higher values which results into improved AC output at reduced harmonic distortion. Due to low passive component count in the proposed inverters, weight, volume and losses decreases resulting into increase in efficiency. The proposed inverters can be used in various DC-AC and DC-DC power conversions in renewable energy applications due to their high-voltage gain, better immunity to EMI noise and higher reliability. The detailed steady-state analysis of the two proposed SLC-ZSIs is given in this study. Scaled down experimentation has been carried out to verify the performance of the proposed inverters.

New Hybrid Structure Based on Improved Switched Inductor Z-Source and Parallel Inverters for Renewable Energy Systems

Nowadays, more and more distributed generations and renewable energy sources, such as wind, solar and tidal power, are connected to the public grid by the means of power inverters. They often form microgrids before being connected to the public grid. Due to the availability of high current power electronic devices, it is inevitable to use several inverters in parallel for high-power and/or low-cost applications. So, inverters should be connected in parallel to provide system redundancy and high reliability, which are important for critical customers. In this paper, the modeling, designing and stability analysis of parallel-connected three-phase inverters are derived for application in renewable energy systems. To enlarge voltage adjustability, the proposed inverter employs an improved switched inductor Z-source impedance network to couple the main circuit and the power source. Compared with the classical Z-source inverter (ZSI) and switched inductor Z-source inverter (SL-ZSI), the proposed inverter significantly increases the voltage boost inversion ability and also can increase the power capacity and the reliability of inverter systems. The proposed topology and its performances are validated using simulation results which are obtained in Matlab/Simulink.

Design and implementation of maximum constant boost switched inductor z-source inverter for three-phase on-line uninterrupted power supply

Purpose – The purpose of this paper is to present the Switched Inductor Z-Source Inverter (SLZSI) topology for three-phase on-line uninterruptible power supply (UPS) by employing third harmonic injected maximum constant boost pulse width modulation (PWM) control. Conventional UPS consists of step-up transformer or boost chopper along with voltage source inverter (VSI) which reduces the efficiency and increases energy conversion cost. The proposed three-phase UPS by using SLZSI has the voltage boost capability through shoot through zero state which is not available in traditional VSI and current source inverter. Design/methodology/approach – Performance of three-phase on-line UPS based on ZLZSI by using third harmonic injected maximum constant boost PWM control is analyzed and evaluated in MATLAB/Simulink software and the results are compared with Z-source inverter (ZSI) fed UPS. Experimental results are presented for the validation of the simulation and theoretical analysis. Findings – The output voltages, currents, THD values, voltage stress and efficiencies for different loading condition are determined and compared with the theoretical values and UPS with ZSI. The experimental results validate the theoretical and simulation results. Originality/value – Compared with the traditional ZSI, the SLZSI provides high-voltage boost inversion ability with a very short shoot through zero state. This proposed UPS by using SLZSI increases the efficiency with less number of components, reduces the harmonics, increases the voltage gain and reduces the voltage stress.

Class of high boost inverters based on switched‐inductor structure

This study deals with a class of the switched-inductor boost inverters (SLBIs) including the DC-linked type, continuous, discontinuous and ripple input current topologies. Compared with the conventional switched boost inverters, the SLBIs add only three diodes and one inductor to obtain a strong boost factor. In comparison with the conventional switched-inductor Z-source inverters (ZSIs) for the same voltage gain at the same modulation indexes, the proposed SLBIs use one more active switch and less passive components which results in reducing the size and cost. Moreover, the efficiency of the proposed inverters is improved in comparison with the conventional switched-inductor ZSIs. Analysis and operating principles are presented. A laboratory prototype was built with 24, 36, 48 V DC input and 127 Vrms output voltage to test high boost ability of the proposed inverters.

Modeling and Experimental Study of Three-phase Improved Switched Inductor Z-Source Inverter

This paper presents the detailed modelling and experimental verification of a proposed three-phase Improved Switched Inductor Z-Source Inverter (ISL ZSI). Because of the limitations of classical Z-source inverter, the ISL ZSI has been proposed to increase the conversion voltage gain, to reduce the voltage stress on the capacitor of Z-network and to remove the inrush current. In this paper, a detailed model of the proposed inverter is presented and analyzed. PWM control and relationships of voltage gain and voltage stress versus modulation index are explained. Then, a detailed loss model for the ISL ZSI is derived. Simulation results are obtained to confirm the proposed topology and its loss model. Then, a prototype of 250 W is presented and experimentally tested. A good match is obtained for calculation, simulation and experiment.

Development of Multi-Cell Active Switched- Capacitor and Switched-Inductor Z-Source Inverter Topologies

This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.

Comparative Evaluation of Generalized Multicell Impedance Source Inverter for Drives

Voltage-Source Inverter is limited by its only voltage step-down operation. In adding with extra boosting the flexibility is kept active for the number of semiconductors which is unchanged, voltage-type Z-source inverter was earlier proposed. These new classes of inverter is generally less sensitive to electromagnetic noises. However, their boosting capabilities are anyhow less with high component stresses and poorer spectral performances caused by low modulation index ratios. Their boosting gains are, therefore, restricted in practice. To overcome these we use the generalized switched-inductor Z-source inverter is proposed, By comparing with PWM technique and SPWM technique, whose extra boosting abilities and other advantages have been verified in simulation analysis and experiment. DOI: http://dx.doi.org/10.11591/ijpeds.v4i2.5128

Modified Embedded Switched Inductor Z Source Inverter

A novel modified embedded switched inductor Z-source inverter is proposed by inserting the photovoltaic panels at various locations to improve the output voltage boosting performance. The proposed inverter have the concepts of embedded and switched inductor Z source network to have better features in terms of increased voltage boost inversion ability, continuous input current, reduced voltage stress on the switches/capacitors. Simulations are carried out by employing (120°) pulse width modulation scheme. Hardware implementation of the proposed topology of rating 150 W, 60 V is made and the results are experimentally verified. Switch device power and reliability evaluation of the proposed inverter are also calculated.

Design and Realization of Maximum Boost Switched Inductor Z-Source Inverter for Three Phase On-Line UPS

This paper proposes switched inductor Z-source inverter (SL-ZSI) for three phase on-line UPS with high voltage boost ability. The maximum boost control is attained using third harmonic injection. The proposed inverter employs a unique impedance network to couple the main circuit and the power source. SL-ZSI adds two inductors and six diodes to enlarge voltage adjustability. To obtain a high voltage conversion ratio it needs only a shoot through state. SL-ZSI concept can be applied to all dc- to –ac, ac-to-dc, ac-to-ac, and dc-to-dc power conversion. The proposed method is simulated using MATLAB/Simulink and the result satisfies the theoretical analysis