Impedance networks cover the entire of electric power conversion from dc (converter, rectifier), ac (inverter), to phase and frequency conversion (ac-ac) in a wide range of applications. Various converter topologies have been reported in the literature to overcome the limitations and problems of the traditional voltage source, current source as well as various classical buck-boost, unidirectional, and bidirectional converter topologies. Proper implementation of the impedance-source network with appropriate switching configurations and topologies reduces the number of power conversion stages in the system power chain, which may improve the reliability and performance of the power system. The first part of this paper provides a comprehensive review of the various impedance-source-networks-based power converters and discusses the main topologies from an application point of view. This review paper is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers. A comprehensive review of various modeling, control, and modulation techniques for the impedance-source converters/inverters will be presented in Part II.

Impedance-Source Networks for Electric Power Conversion Part I: A Topological Review

This study presents a novel three-level neutral-point-clamped quasi-Z-source inverter in the single-stage buck-boost multilevel inverter family. The topology was derived by combining the properties of the quasi-Z-source network with those of a three-level neutral point clamped inverter. It features such advantages as low voltage stress of the switches, single-stage buck-boost power conversion, continuous input current, short-circuit withstandability and low total harmonic distortion of the output voltage and current. The authors present a steady state analysis of the topology along with a special modulation technique to distribute shoot-through states during the whole fundamental period. Component design guidelines for a single-phase case study system are described. All the findings have been confirmed by simulations and experiments. The topology could be recommended for applications requiring continuous input current, high input voltage gain and enhanced quality of the output voltage.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2013.0904

Single phase three-level neutral-point-clamped quasi-Z-source inverter

Application of multilevel inverters for higher voltage goals in industries has become more popular. In this study, new structures for symmetric, asymmetric and hybrid multilevel inverter are recommended. The proposed hybrid structure is used in high-voltage levels. The proposed structures can generate a great number of output voltage levels with minimum number of power electronic components such as insulated gate bipolar transistors (IGBTs) and gate drivers. For proposed asymmetric and hybrid inverter, new methods for determination of dc voltage sources values are presented. Comparison of the results of various multilevel inverters is presented to reflect the merits of the recommended structures. The operations of the proposed multilevel inverter structures are verified with the experimental and simulation results of an asymmetric 15-level prototype and a 19-level hybrid inverter. Fundamental frequency-switching method is applied to the new topologies to trigger the power switches for controlling the voltage levels generated on the output. Verification of the analytical results is performed using MATLAB/SIMULINK software.

New hybrid structure for multilevel inverter with fewer number of components for high-voltage levels

A comprehensive review of dynamic voltage restorers

In this study, a new topology for switched Z-source inverter is proposed. This inverter in comparison with the conventional Z-source inverter needs higher number of active elements, lower number of capacitors and inductors. Reduction of weight, size and cost are the main advantages of the proposed topology. In addition, this inverter is able to solve the problem of short circuit across the inverter leg and consists of higher value of voltage gain when compared with the conventional switched boost inverter. Moreover, the developed topology of the proposed inverter based on switched-inductor cells is introduced. The performance of the proposed inverter in different operating modes is investigated. The proposed topologies are also compared with the conventional Z-source inverters from different points of view such as number of elements, the voltage gain and capability of tolerate the inverter short circuit. Finally, the accuracy performance of the proposed inverter is reconfirmed by using the simulation results in EMTDC/PSCAD software and also experimental results.

Developed embedded switched-Z-source inverter

This study presents a new inverter topology based on mixture of cascaded basic units and one H-bridge unit. The basic unit includes one Z source, one DC voltage source and two switches generating two voltage levels. The cascaded basic units produce positive and zero-voltage levels and in the same time suggested inverter obtains positive, zero- and negative voltage levels, as a result the number of power semiconductor switches is reduced with respect to traditional multilevel inverters. In this topology, output voltage amplitude is not limited to DC sources voltage summation similar to traditional cascaded multilevel inverters and can be boosted with Z network shoot-through state control; therefore other DC/DC converters are not needed and it is more reliable against short circuit. Besides as compared with traditional Z -source inverter, total harmonic distortion of injected voltage is decreased in the suggested inverter topology. The performance of proposed topology and its controller are validated with simulation results using MATLAB/SIMULINK software and the validity of the proposed multilevel inverter-based Z source is verified by experimental results.

Z-source-based multilevel inverter with reduction of switches

This study proposes a new topology of cascaded transformer-based multilevel inverter using single Z-source. The suggested circuit consists of only one Z network and one DC voltage source; as a result installation area is reduced. In this topology, the output voltage amplitude is not limited to DC voltage source similar to traditional cascaded transformer-based multilevel inverter and can be increased with Z network shoot-through state control flexibly. Besides, the same as traditional Z-source inverter, it is more reliable against short circuit. Also, a particular switching algorithm has been suggested for presented inverter, which can obtain total harmonic distortion (THD) of output voltage nearly constant for different boost ratio. Moreover, as compared to traditional Z-source inverter, the THD of output voltage is decreased in the suggested topology. The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2012.0636

Switching algorithm for single Z-source boost multilevel inverter with ability of voltage control

This paper proposes a new topology of Z-source based cascaded multilevel inverter. In this topology the output voltage is not limited to DC voltage source similar to traditional cascade multilevel inverter and can be increased with Z network shoot-through state control. Besides, it is more reliable against short circuit. Performance of suggested topology in the closed-loop control scheme is described in the Dynamic Voltage Restorer (DVR) structure. Compensation capability of the proposed DVR increases. The operating principle, switching algorithm and characteristics of proposed topology are described in this paper. The performance of suggested inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software.

DVR based cascaded multilevel Z-source inverter

Double input Z-source inverter applicable in dual-star PMSG based wind turbine

This study combines quasi-Z-source into the five-level inverter using coupled inductors. The suggested circuit consists of only one dc voltage source, one quasi-Z-network, six power switches and only one set of coupled inductors. In this topology, the output voltage amplitude is not limited to dc voltage source and it is reliable and higher efficiency because of quasi-Z-network presence. This study also proposes new switching algorithms for the inverter based on pulse width modulation (PWM) and space vector control (SVC) algorithms, which cause boosting capability of output voltage with low total harmonic distortion (THD). This PWM algorithm is particular one, which calculates dwelling time for each switch in every sample time. The proposed SVC algorithm generates a voltage vector with very low harmonic distortion and reduced switching frequency. The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system. These results demonstrate the proposed inverter with suggested algorithm can generate a wide range of load voltage.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2013.0499

Ali Reza Dehghanzadeh

Papers

Z-source-based multilevel inverter with reduction of switches

Switching algorithm for single Z-source boost multilevel inverter with ability of voltage control

DVR based cascaded multilevel Z-source inverter

Double input Z-source inverter applicable in dual-star PMSG based wind turbine

Extended switching algorithms based space vector control for five-level quasi-Z-source inverter with coupled inductors