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In this study, an improved topology of half-bridge switched boost inverter with low voltage stress on capacitors is proposed. The proposed half-bridge quasi-switched boost inverter, in comparison with the half-bridge Z-source inverter with two Z-networks, has less passive components. Moreover, the proposed topology generates high voltage gain comparing with the conventional topologies and has stable operation. Producing zero voltage level at the output is the other advantage of the proposed inverter, in comparison with the conventional half-bridge inverter. The small-signal model and steady-state analysis of the proposed inverter in different operating modes are given. Moreover, signal flow graph using small-signal analysis and design considerations are derived. In addition, switching pattern for the proposed inverter is presented and power losses are calculated. A comprehensive comparison is done between the proposed topology and conventional inverters from different points of view such as number of components, volume, inrush current, tolerance of shoot-through and so on. Finally, the simulation and experimental results are given to demonstrate dynamic response, effect of undesirable shoot-through and the accuracy of the given theories.

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In this paper, 2 types of half-bridge quasi-Z-source inverters with detailed analysis are proposed. Unlike the classical half-bridge inverter, both types of proposed half-bridge inverters can generate zero voltage level in output. Moreover, lack of continuous input current in conventional half-bridge inverters is resolved by the second type of proposed inverters. One of the important advantages of proposed inverters is using the 1 impedance network only with 2 capacitors and 2 inductors; whereas, most of the half-bridge Z-source inverters have more than 1 impedance network or use additional semiconductor elements. In this paper, operation principles of proposed inverters in different operating modes are discussed. Then, design considerations and calculation of critical Inductance in boundary conditions between 2 different states are provided. Next, power circuit of general topology with multiple DC sources and derivation of subcircuits are proposed. Finally, to verify validity of derived equations, simulation results using PSCAD/EMTDC software and experimental results are provided.KEYWORDS half-bridge inverter, quasi-Z-source inverter, shoot-through, Z-source inverter

In this study, a new topology for Z-source inverter is proposed without adding additional passive elements to the conventional impedance network. The proposed topology is double-fed and can generate high voltage gain in comparison with the conventional Z-source inverters. By using improved simple boost modulation technique, the function of boost factor in the proposed inverter is general and variable. In other words, not only the boost factor of the proposed inverter depends on value of shoot-through (ST) duty cycle but also is dependent on the value of switching factor and controllable by changing specific signals in switching pattern. In this study, steady-state analysis of the proposed inverter in different operating modes such as ST operating mode, adjacent-non-ST (A-nST) operating mode and non-A-nST operating mode are presented. Design considerations and critical inductance between proper and improper operations are calculated. Then, the used modulation technique and switching pattern are investigated and comparison between the proposed and conventional inverters from different points of view is done. Finally, simulation results using PSCAD/EMTDC software and experimental results are presented to verify theoretical discussions, derived equations and correct operation of the proposed inverter.