A Class of Quasi-Z-Source Inverters

Abstract

In this paper, theoretical results are shown for several novel inverters. These inverters are similar to the ZSource inverters presented in previous works, but have several advantages, including in some combination; lower component ratings, reduced source stress, reduced component count and simplified control strategies. Like the Z-Source inverter, these inverters are particularly suited for applications which require a large range of gain, such as in motor controllers or renewable energy. Simulation and experimental results are shown for one topology to verify the analysis. Also, a back-to-back inverter system featuring bidirectionality on both inverters, as well as secondary energy storage with only a single additional switch, is shown.

Operation of Resonant DC/DC Converter in the BUCK Operation Regime

“…1 with DC source qZ circuit, bridge mode transistors' commutator, LC resonance circuit in the primary winding of an insulating transformer with secondary winding introduced in the voltage doubling rectifier operating on voltage smoothing capacitor by-passed load, is under examination. Sources [1,2,3] show that such converter can operate as in so named normal regime at switching frequency equally to the resonant one, in the BOOST case at the same control frequency and in the BUCK case when output voltage of the load can be regulated below value corresponding to the normal one. At that later can be applied an increasing frequency of switching ωsw that shortening the normal resonant current halfwave determined by the parameters of the resonant circuit ωr [1,2].…”

“…Applying the triangular shape of current the amplitude of voltage can be calculated as a product of approximately time duration of switching half-cycle and a fourth of the amplitude of current in resonant circuit over capacitance of the resonant circuit: Fig. 1) is used in circuit of DC supply source for provision of operation of switching converters as in BUCK as well in the BOOST mode [1,2,10,11]. At the later periodically shortening of converter legs named as shoot-through cycles can be applied increasing in result voltage at output of a qZ link [2,10].…”

“…1) is used in circuit of DC supply source for provision of operation of switching converters as in BUCK as well in the BOOST mode [1,2,10,11]. At the later periodically shortening of converter legs named as shoot-through cycles can be applied increasing in result voltage at output of a qZ link [2,10].…”

“…The paper [1] proposes to introduce in supply circuit of the DC/DC series resonant converter the qZ circuit [2,3,10,11,12] which allows to obtain operation of an inverter-based converter as in BOOST as well in BUCK operation regimes. At that the later should be provided increasing a control switching frequency above the resonant one which depends on the accepted values of the resonant circuit inductance L and series resonant capacitor C [3,4,5,6].…”

An Extended Switched-inductor Quasi-Z-source Inverter

“…Thus, the control strategies are not efficient to improve the boost ability. Another solution is to change the structure of Zsource network, which has been studied extensively [9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”