• Journal of Power Electronics
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• v.13 no.1
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• pp.9-19
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• 2013

In this paper, a ripple input current embedded switched-inductor Z-source inverter (rESL-ZSI) and a continuous input current embedded switched-inductor Z-source inverter (cESL-ZSI) are proposed by inserting two dc sources into the switched-inductor cells. The proposed inverters provide a high boost voltage inversion ability, a lower voltage stress across the active switching devices, a continuous input current and a reduced voltage stress on the capacitors. In addition, they can suppress the startup inrush current, which otherwise might destroy the devices. This paper presents the operating principles, analysis, and simulation results, and compares them to the conventional switched-inductor Z-source inverter. In order to verify the performance of the proposed converters, a laboratory prototype was constructed with 60 $V_{dc}$ input to test both configurations.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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• pp.123-130
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• 2013

This paper proposes the switched trans Z-source inverter(STZSI) which combined the characteristics of the trans Z-source inverter(TZSI) and the switched inductor Z-source inverter(SLZSI). The proposed STZSI has the same performance compared with the SLZSI which is improved the voltage boost performance of the conventional typical X-shaped ZSI, and it has advantage that circuit structure of Z-impedance network is more simple. And, in order to step up the voltage boost factor under the condition of the same duty ratio, unlike the SLZSI adding the inductors and diodes, the proposed method is dune by changing the turn ratio of trans primary winding of Z-impedance network. To confirm the validity of the proposed method, PSIM simulation and a DSP(TMS320F28335) based experiment were performed using trans with turn ratio 1 and 2 under the condition of the input DC voltage VI=50V, duty ratio D=0.1 and D=0.15. As a result, under the same input/ouput condition, the inverter arm voltage stress of the proposed method is reduced to about 15%-22% as compared with typical X-shaped ZSI, and the elements in Z-impedance network of the proposed method is reduced as compared with the SLZSI.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1716-1724
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• 2016

This paper proposes both an active-switched quasi-Z-source inverter (AS-qZSI) and an extended active-switched qZSI (EAS-qZSI), which are based on the classic qZSI. The proposed AS-qZSI adds only one active switch and one diode to the classic qZSI for increasing the voltage boost capability. Compared with other topologies based on the switched-inductor/capacitor qZSI, the proposed AS-qZSI requires fewer passive components in the impedance network under the same boost capability. Additionally, the proposed EAS-qZSI is designed by adding one inductor and three diodes to the AS-qZSI, which offers enhanced boost capability and lower voltage stress across the switches. The performances of the two proposed topologies are verified by simulation and experimental results obtained from a prototype with a 32-bit DSP built in a laboratory.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.589-599
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• 2014

On the basis of the traditional ZSI (Z-source inverter), this paper presents a ESL-${\Gamma}$-ZSI, which uses a unique ${\Gamma}$-shaped impedance network and an extended SL network for boosting its output voltage in addition to their usual voltage-buck behavior. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductors. Capacitor voltage stress of ESL-${\Gamma}$-ZSI is a constant when 1>D>0, and ESL-${\Gamma}$-ZSI has small inductor current stress. The working principle of ESL-${\Gamma}$-ZSI and comparison with the classical ZSI and SL- ZSI are analyzed in detail. The power loss comparison between ESL-${\Gamma}$-ZSI and Cuk converter is analyzed detailedly. Simulation and experimental results are given to demonstrate the operation features of the inverter.

• Journal of Power Electronics
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• v.14 no.5
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• pp.834-841
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• 2014

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.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.3
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• pp.290-296
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• 2014

This paper presents a design strategy for the control of the Z-source inverter (ZSI). For the Z-network capacitor voltage control, the average current model is derived to describe the dynamics of the voltage control and the controller outputs the average current command for the capacitor. Z-network inductor current reference is derived from the average current model of the Z-network capacitor. The inner current control loop outputs the average voltage command for the Z-network inductor and the shoot-through duty ratio of the ZSI is calculated from the output using the average voltage model of the Z-network inductor. The gain values of the current and voltage controllers are directly obtained by the Z-network parameters and desired bandwidth of each controller without a gain tuning process.

• Journal of IKEEE
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• v.21 no.2
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• pp.166-169
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• 2017

In this paper, maximum boost discrete PWM(DPWM) method of Z-Source Inverter(ZSI) is proposed. In general, a DPWM method is used to reduce the switching losses of the inverters and increase the efficiencies. The maximum boost PWM method of Z-Source Inverters is combined with the DPWM method. The proposed Maximum boost DPWM of ZSI is analyzed and it shows how to reduce the switching losses of ZSI. An experimental system has been built and tested to verify the effectiveness of the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.8-19
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• 2011

This paper was compared for the output voltage and efficiency of the single-phase Z-source inverter(ZSI) according to shoot through duty ratio D. The eight single-phase ZSI in this study are typical ZSI, Embedded ZSI(EZSI), Improved ZSI(IZSI), Quasi ZSI(QZSI), Series ZSI, Trans ZSI(TSI), Switched inductor ZSI(SL-ZSI) and Extended boost ZSI (exZSI). The eight ZSI are divided into two Groups. ; Group-1 which is ZSI with the ordinary voltage boost factor B, and Group-2 which is ZSI with the maximum voltage boost factor B. For the execution of the proposed study, the PSIM simulation was achieved under the condition of input DC voltage=150[V] of ZSI, load =30[${\Omega}$] and 60[Hz] output filter. The output voltage and efficiency of each ZSI were calculated within the limits of D=0.1~0.4. As a result, the output peak voltage of Group-2 was suddenly increased in a specified duty ratio D, and its efficiency was rapidly decreased. On the contrary, Group-1 shown the output and efficiency characteristics without sudden change compared to Group-2 despite the duty ratio increase. The efficiency of the Group-2 was sharply declined at duty ratio D of the most output voltage, but, in case of Group-1, the efficiency was slightly declined. Finally, the input DC current of ZSI with DCM and CCM was discussed.

• Journal of Power Electronics
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• v.9 no.3
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• pp.335-342
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• 2009

The Z-source inverter (ZSI) provides unique features such as the ability to boost dc voltage with a single stage simple structure. Although the dc capacitor voltage can be boosted by a shoot-through state, the voltage stress across the switching devices is rapidly increased, so high switching device power is required at the ZSI. In this paper, algorithms for minimizing the voltage stress are suggested. The possible operating region for obtaining a desired ac output voltage according to both the shoot-through time and active state time is investigated. The reference capacitor voltages are derived for minimizing the voltage stress at any desired ac output voltage by considering the dc input voltage. The proposed methods are carried out through the simulation studies and experiments with 32-bit DSP.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.541-549
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• 2014

In this paper, an extended switched-inductor quasi-Z-source inverter (ESL-qZSI) with high boost voltage inversion ability is presented, which combines the SL-qZSI with the traditional boost converter, as well as improves the switched-inductor cell. Compared with the classic qZSI topologies, the proposed topology reduces the voltage stresses of capacitors, power devices and diodes for the same input and output voltage. Furthermore, the conversion efficiency is improved. The operation principle of the proposed topology is analyzed in details, which is followed by the comparison between the three topologies. In addition, the performance of the proposed topology is verified by simulations and experiments.