• 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 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.

• 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.

• 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.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.105-106
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• 2013

This paper proposes a new topology with active switched-capacitor and switched-inductor impedance network, which can obtain a high boost factor with small shoot-through time. The proposed topology uses an active switched capacitor and switched-inductor impedance network in order to couple the main circuit and input dc source for boosting the output voltage. The proposed topology contains all advantages of the classical Z-source inverter. Comparing with other topologies, the proposed topology uses lesser component and the voltage boost inversion ability significantly increases. The theoretical analysis, pulse width modulation control strategies, and a comparison with classical ZSI have been given in this paper. Both simulation and experimental results will be presented to verify the advantages of the proposed topology.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.57-66
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• 2012

When typical Z-source DC/AC inverter(ZSI) is operated in high voltage gain area, because of its high duty ratio, voltage and current stress in Z-network of typical ZSI are increased. This paper proposes a new switched trans ZSI(STZSI) with two switched trans cells which consist of one trans and two diodes. To confirm the operation performance of the proposed system, the PSIM simulation is performed for typical ZSI, switched inductor ZSI and the proposed STZSI. Voltage / current stress and transient state characteristics of each method are compared under the condition of DC input voltage 100[V] and output phase voltage 66[Vrms]. As a result, we confirmed that transient state of the proposed STZSI is short compared with the conventional ZSI because the high voltage gain is obtained using the same duty ratio, also a low duty ratio is required for the same output voltage. Finally, we could know the proposed system have low voltage and current stress in Z-network compared with the conventional ZSI.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.714-723
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• 2012

A new Z-source inverter (ZSI) topology is developed to improve voltage boost ability. The proposed topology is modified from the switched inductor topology by adding some more inductors and diodes into inductor branch to the conventional Z-source network. The modulation methods developed for the conventional ZSI can be easily utilized in the proposed ZSI. The proposed ZSI has an ability to obtain a higher voltage boost ratio compared with the conventional ZSI under the same shoot-through duty ratio. Since a smaller shoot-through duty ratio is required for high voltage boost, the proposed ZSI is able to reduce the voltage stress on Z-source capacitor and inverter-bridge. Theoretical analysis and operating principle of the proposed topology are explicitly described. In addition, the design guideline of the proposed Z-source network as well as the PWM control method to achieve the desired voltage boost factor is also analyzed in detail. The improved performances are validated by both simulation and experiment.

• 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 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.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.488-489
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• 2014

본 논문에서는 Z-소스 인버터 (ZSI)의 임피던스 네트워크 내 인덕터 및 커패시터 등 수동소자 수를 감소시키면서 전압 증폭율을 증가시키기 위하여 1개의 스위칭소자를 더 사용하는 스위치 인덕터 구조를 가지는 회로를 제시한다. 이 제시한 회로에서 암단락시간과 첨가된 스위칭소자의 스위칭을 위한 PWM제어방법을 기술한다. 시뮬레이션을 통하여 제시한 스위치 인덕터-스위치 부스터 ZSI의 동작 및 특성의 타당성을 확인한다.