Z-source Inverter Research Articles

Model-Free Predictive Control for Improved Performance and Robustness of Three-Phase Quasi Z-Source Inverters

Model-Free Predictive Control for Improved Performance and Robustness of Three-Phase Quasi Z-Source Inverters

Voltage lift technique-based quasi Z-source inverter for electric vehicle functioning

Voltage lift technique-based quasi Z-source inverter for electric vehicle functioning

PV-Assisted grid connected multi output electric vehicle charger with PV2V, G2V and PV2G functions.

The demand for renewable energy-based Electric Vehicle (EV) charging infrastructure is increasing in recent years. Solar PV based EV charging method is preferred as it has simple energy harvesting technique. The PV system is an uncertain power source, where the power generation is varied with respect to the availability of sunlight. So, that the charging station requires a backup power supply for the uninterrupted charging. For the integrated power sources, the charging station requires a simple and efficient conversion unit for the DC/AC/DC conversion. In this work, a modified Z-source inverter (MZSI) is developed for the multiport EV charger using PV and grid. The proposed MZSI is connected between the input and output sides to boost the voltage as per the demand at the battery side. In order to connect many battery units with the charger, the capacitors used in the MZSI are split as per the required number of charging ports. This developed converter topology operates the systems in four different modes like PV-Grid, PV-battery, grid-battery, and battery-grid. The performance of this proposed work has been validated in MATLAB/Simulink® and in the experimental setup. The experimental setup has been developed with two charging ports for obtaining 250W at each charger end which cumulatively produces 500W output across both chargers with an efficiency of 90.18%.

Voltage lift technique-based quasi Z-Source inverter for electric vehicles functioning

Voltage lift technique-based quasi Z-Source inverter for electric vehicles functioning

Advancements in multilevel inverter technologies for photovoltaic-Z-source based EV applications: A comprehensive analysis and future directions

Global demand for electricity has risen, driving a shift toward sustainable energy sources like Photovoltaic (PV) systems. Despite their efficiency challenges compared to traditional fuels, significant investments and research are advancing the technology. This paper investigates multilevel inverter topologies, with a focus on Z-source technology for high-power PV applications. The study begins with an overview of the growing demand for alternative energy sources and the role of multilevel inverters in enhancing PV system performance. It discusses prominent multilevel inverter topologies, such as Neutral Point Clamped (NPC) and Cascaded H-Bridge (CHB) inverters, as well as control techniques including Pulse Width Modulation (PWM) and Predictive Control. Furthermore, it explores the functionality of Z-source inverters both with and without PV systems, highlighting their ability to provide voltage boosting, fault tolerance, and improved power quality. For load purposes, Electric Vehicle (EV) charging has been incorporated. The paper uses MATLAB/Simulink to compare multilevel inverter configurations and finds that the CHB inverter with Z-source is superior for PV applications due to its lower Total Harmonic Distortion (THD) and reduced semiconductor usage. The study also simulates a hybrid storage system with batteries and supercapacitors. The paper concludes with insights into future research directions, advanced control strategies, optimization techniques, and grid integration methods. These avenues promise further enhancement of efficiency, reliability, and grid compatibility for multilevel inverters in PV systems. Overall, this research contributes to the selection of optimal multilevel converter topologies for improving the performance of PV systems and advancing the integration of renewable energy into the electrical grid. The findings offer valuable insights for researchers, practitioners, and policymakers working toward a sustainable energy future.

Enhancing PV Systems with Intelligent MPPT and Improved control strategy of Z-Source Inverter

Abstract The Improved Z-Source Inverter (IZSI) has gained attention in the photovoltaic industry for its ability to boost PV voltage with a single-stage topology, simplifying system design and reducing costs. However, research on integrating IZSI into PV systems, particularly regarding the Maximum Power Point Tracker (MPPT) and IZSI control strategy, is limited. This study proposes an Intelligent Improved Particle Swarm Optimization (IPSO) algorithm as an MPPT method for PV systems under constant and varying irradiance conditions. The IPSO algorithm is compared to the FPA, CSA, and traditional MPPT algorithm (PSO), and the results demonstrate that IPSO outperforms all algorithms in terms of speed, efficiency, and convergence in finding the Maximum Power Point (MPP). Two methods, Simple Boost Control (SBC) and Maximum Constant Boost Control with Third Harmonic Injection (THIMCBC), are employed to control IZSI. Simulation results using MATLAB-Simulink show that both strategies successfully find and track the MPP, but THIMCBC exhibits superior voltage-boosting performance compared to SBC. Overall, the proposed IZSI topology with the IPSO MPPT method and THIMCBC IZSI control strategy offers several advantages, including improved voltage boost ability, reduced z-source capacitor voltage stress, inherent inrush current limitation, and cost-effectiveness. These advantages make the proposed system a promising solution for photovoltaic systems.

FOPID controlled PV based QBC fed gamma Z-source inverter applicable for pump operations in an induction motor drive

<span lang="EN-US">A closed loop current mode-fractional-order-PID (CM-FOPID) controlled and PV based quadratic-boost-converter (QBC) fed gamma Z-Source Inverter with Induction motor system (PV-QBC-GZSI-IMS) for pump operation is proposed here. This work recommends a combination of QBC with gamma Z-source-inverter between the DC link source and asynchronous motor system. This will reduce the voltage rating of PV panel and its initial cost. GZSI reduces the current spikes in stator current. The objective of this research work is to regulate the speed of PV-QBC-GZSI-IMS. This effort deals with the closed loop response of PV-QBC-GZSI-IMS accompanied by current-mode-proportional integral (CM-PI) and CM-FOPID controllers. The performance investigations are analyzed with the control of QBC fed Gamma Z-source inverter with motor load using CM-PI and CM-FOPID controllers and the detailed comparison has been presented. MATLAB/Simulink outputs obtained with their respective speed and torque characteristics in time domain have been depicted. The closed loop CM-FOPID control of PV-QBC-GZSI-IMS is superior to the closed loop CM-PI control of PV-QBC-GZSI-IMS. The proposed QBC-converter reduces the voltage rating of PV panel and GZSI reduces current spikes in motor. The novelty of the article is to enhance the dynamic response of PV-QBC-GZSI-IMS using FOPID. The steady state error in torque is reduced to 0.52 N-m using FOPID.</span>

Investigation of bidirectional quasi Z-Source inverter for BLDC drive with modified shoot-through hysteresis current control in low power EV applications

Investigation of bidirectional quasi Z-Source inverter for BLDC drive with modified shoot-through hysteresis current control in low power EV applications

FC-PV-battery-Z source-BBO integrated unified power quality conditioner for sensitive load & EV charging station

The proposed integrated system combines of fuel cell (FC), photovoltaic (PV), battery, Z-source and Biogeography-Based Optimization (BBO) based Unified Power Quality Conditioner (UPQC) compensator aims to provide a high-quality power supply to sensitive loads, such as electrical, electronics, medical equipment, Electrical Vehicles (EV), or critical industrial processes. It can regulate voltage, mitigate power disturbances (e.g., voltage sags, swells, flicker, voltage interruption, harmonics, reactive power etc.), and ensure a stable power supply. Additionally, it can facilitate EV charging stations by managing the power flow and optimizing charging processes. The PV or FC based Z-source inverter can control and regulate power flow in both directions. It operates with a unique impedance network, allowing for voltage boosting or bucking. The Z-source inverter enhances the flexibility and control of power flow in the system. The fuel cell generates electricity through an electrochemical process, typically using hydrogen as a fuel source, while the PV array converts sunlight into electrical energy. The FC-PV system provides a renewable and clean energy source. The battery serves as an energy storage device within the integrated UPQC system. It stores excess energy produced by the FC-PV system or from the grid during off-peak hours and releases it when needed, contributing to load balancing and stability. Biogeography-Based Optimization (BBO)-based Selected Harmonic Elimination Pulse Width Modulation (SHE-PWM) technique calculate the proper inverter switching angles and control the total harmonic distortion (%THD). Grid connected EV charging station produce nonlinear current and pollute the DC-link system. The proposed FC-PV-Z source-BBO based UPQC and its control strategy can enhance the EV-charging induced PQ (power quality) issues, eliminate the voltage and current harmonic or reduce overall voltage and current %THD control the proper reactive power, improve the power factor, restoring the flicker, transient, swells and sags of the micro grid, grid or smart grid and completely moderate the fluctuations of DC-link voltage.

Comparison Of Conventional Z-source Inverter And Modified-Z-source Inverters

This paper investigates the performance analysis of the Modified-Z-Source Inverter with a simple voltage boost control method. The Z-Source network provides an efficient method of converting electricity in grid-connected solar applications, requiring only one step to fulfill the requirements. Nevertheless, high voltage stress and high voltage rating capacitor problems plague the Z-source inverter. In order to overcome these problems, a customised Z-network that maintains the same shoot-through duty ratio as a Z-source inverter is utilised to provide high boosted voltage. This research compares the performance of the modified Z-source inverter with the Z-source inverter using MATLAB.

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.

Three-phase bidirectional active split source inverter for automotive traction application

The Split Source Inverter (SSI) is an attractive single-stage boost DC–AC converter topology. It requires fewer components than the Z-source inverter to achieve the boost function and also maintains a continuous input current. However, a significant drawback of this topology is its limited DC-bus voltage utilization. This paper introduces a new inverter topology derived from the SSI, aimed at addressing the DC voltage utilization issue and assessing its viability for traction applications. The new three-phase single-stage boost DC–AC inverter topology is named B-ASSI, and a potential modulation scheme is proposed to accompany it. To verify their functionality, the proposed converter and modulation scheme are simulated using Matlab/Simulink. Furthermore, a Proof of Concept (POC) is executed to experimentally validate the performance of the proposed inverter topology.

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 Grid-Connected PV System Based on Quasi-Z-Source Inverter With Maximum Power Extraction

This paper proposes an approach to link photovoltaic arrays with the AC grid using Z-source inverter (ZSI) and quasi-Z-source inverter (QZSI) topologies. These topologies boost the DC-link voltage and invert it to AC voltage in one stage, resulting in a reduction in the overall system size and cost. The paper presents a control technique that fixes the DC-link voltage on the inverter bridge terminals, tracks the maximum power point (MPPT), and controls the amount and quality of power injected into the grid using unity power factor. The proposed control algorithm utilizes two independent control variables, shoot-through duty cycle (ST) and modulation index, to decouple the control of the DC and AC sides. The effectiveness of the proposed control technique is verified through simulations of a grid-connected PV system. The results demonstrate that the proposed system can efficiently extract maximum power from PV arrays while regulating the DC-link voltage and ensuring unity power factor operation. Additionally, experimental testing of ZSI/QZSI further confirms the results of analysis and simulation.

Model Predictive Control-Based Dual-Mode Operation of an Energy-Stored Quasi-Z-Source Photovoltaic Power System

The energy-stored quasi-Z-source inverter (ES-qZSI) has attracted much attention for photovoltaic (PV) power generations, due to its capability to stabilize the PV power fluctuations with simple structure and other advantages of Z-source inverter. The improved dual-mode (DM) ES-qZSI is able to support all-weather operation even at night or cloudy days when PV power is extremely low. Whereas, the traditional proportional-integral (PI) based control suffers from complicated controller design and poor dynamic response during mode transition, due to two sets of PI control required for the daytime and night operation modes. In order to overcome that, this paper proposes a model predictive control strategy for the DM-ES-qZSI PV power system. The system predictive models in both day and night operating modes are derived. The control strategy is disclosed to ensure high performance of the system, through calling the predictive models and defined cost functions of the two modes within a single control loop. Simulation and experiment are carried out to verify the effectiveness of proposed control strategy.

Proposed Z-Source Electrical Propulsion System of a Fuel Cell/Supercapacitor-Powered Ship

The use of green energy to power ships in the marine industry has attracted increasing attention in recent years. This paper presents an inland river cruise ship supplied by a fuel cell (FC) as the main power source and a supercapacitor (SC) as the auxiliary power source. Its propulsion inverter adopts the proposed high-boost Z-source inverter, and the proposed high-voltage-boost Z-source inverter (HVB-ZSI) principle is studied. The advantages of this proposed HVB-ZSI in two cases are verified through simulation. In case 1, it can be seen that the capacitance voltage is only 250 V, and the maximum inductance’s inrush current at the start is less than 200 A. But the capacitance voltage of HVB-ZSI reaches 383 V, and the inrush current is 300 A. While considering different constraints of the propulsion system, four operating modes for the set of the FC and SC are proposed. The small-signal model of the propulsion system is derived, and the control strategy is studied. By controlling the shoot-through duty cycle and modulation factor, the FC power, output power, and state of charge (SOC) of the SC can be controlled. Finally, to verify the performance of the proposed propulsion system, a hybrid power ship prototype equipped with a 7.5 kw propulsion motor is constructed. Four modes of the entire system are simulated by MATLAB/SIMULINK, and its performance is analyzed with experimental results. These results show that the new Z-source propulsion system has a promising application in new energy ships, as it has higher reliability and lower complexity and cost compared to conventional propulsion systems.

PI Controlled Bridged Grid-Connected Solar PV Network for Electric Vehicle Battery Charging

The Z-source inverter (ZSI) topology replaces multiple stages into a single stage in power conversion so it is going to be an appropriate topology for 1-phase grid-connected PV system. In this paper, the various z-source topologies are discussed as available in different literature. This paper has proposed a proportional and integral (PI) Controlled bridged grid-connected solar photovoltaic (PV) network for electrical vehicle charging. The different modulation techniques applied in these topologies have been described. The bridged grid-connected network equipped with solar modules can prove effective in developing charging infrastructures for electric vehicles (EVs) at residential or commercial complexes. The different parameters of this suggested topology may vary during different time instants of a whole day at different modes of procedure i.e solar PV generation to the grid, EV to grid, and both PV and EV to grid. The simulation work has been done with the PWM technique to obtain battery voltage and grid voltage, Fast Fourier Transform, and total harmonic distortion.

Power quality enhancement by using Z-DVR based series voltage compensation with black widow optimization technique

In distribution system, voltage quality issues are the most concerning disturbances influencing the power quality (PQ). As a result, to alleviate this PQ concerns such as sag, swell, fluctuation, interruption, and harmonics on the sensitive load, the series voltage compensator dynamic voltage restorer (DVR) is utilized. Furthermore, a Z-source inverter (ZSI) based DVR is proposed in this paper to improve the power system's voltage restoration properties. To compensate the voltage concerns which is occurs in passive and transmission components, the 3-φ Z-DVR inverter with proportional integral derivative (PID) controller tuned by black widow optimization (BWO). By short circuiting the legs of inverter in the ZSI, prepare the possibility of buck and boost in voltage and utilize the LC impedance grid which incorporated power source to inverter circuit. In addition, to obtain the injecting voltage, PID control scheme for ZSI based DVR is proposed in this paper. The proposed modelling and simulation of DVR is implemented in MATLAB/Simulink tool and the outcomes are analyzed. Furthermore, reduction in voltage concerns, and total harmonics distribution (THD) with BWO tuned PID controller is superior which is 1.01% when compared with existing methods such as Harris Hawks optimization (HHO) based PID, genetic algorithm (GA) based PID controller.

Refine control methodology and implementation of capacitor voltage control for improved switched inductor Z‐source inverter

SummaryNowadays, Z‐source inverter (ZSI) has received several attentions compared to other power converters owing to their simplicity and reliability. In this paper, a refine control methodology of capacitor voltage control is presented based on third‐order small signal analysis. The proposed control is applied to the improved switched inductor ZSI (ISL‐ZSI). Proportional, integral, and derivative controller (PID) is adopted due to their capability to operate with large operation levels, reliable operation, and cheaper implementation. In addition, the function of this control can be achieved even with incomplete system data or parameters variations. ISL‐ZSI has been presented because of its advantages such as the high gain of direct current voltage, low voltage stress for both the Z‐network and the inverter bridge switches, and ensuring good soft starting. In addition, the inrush current has been removed based on its configuration. The proposed control is validated by both experimental and simulation results under input voltage change, load change, and steady‐state operations using DSP F28335 and MATLAB SIMULINK Real‐Time Workspace.

Design and analysis of trans Z-source inverter for electric vehicle applications using neural network-clustering

The presented paper analyzes the detailed design of a trans Z-source inverter (ZSI) with an input from solar photovoltaic (SPV) system. Increase in SPV uses requires highly efficient SPV enabled inverters under varying weather parameters are in high demand in modern smart grid applications. The SPV-trans ZSI has high conversion efficiency because of the single-stage voltage boost conversion capability. In contradiction, the conventional voltage source inverter (VSI) requires an additional step-up transformer to boost the output voltage of inverter. This reduces the efficiency by increasing the volume of set up and also increase the cost of the system. In the proposed SPV system it provides a better output against VSI. The increase in inverter output voltage is because of shoot through time period present in ZSI. It also reduces the voltage stress and harmonics content as compared to VSI. The proposed model has been validated through MATLAB simulation.