• Journal of IKEEE
• /
• v.19 no.1
• /
• pp.73-79
• /
• 2015

In this paper, maximum boost space vector pulse-width modulation(MBSVPWM) strategy of Z-Source Inverters(ZSIs) is proposed. Conventional space vector pulse-width modulation(SVPWM) method of Voltage Source Inverters(VSIs) is modified to produce unique PWM patterns that realize the maximum boost control of ZSIs. This proposed method minimizes the switching power losses of ZSIs by reducing the numbers of the shoot-through states. Moreover, some switches keep ON state and the switching transitions do not occur during the specific sectors. An experimental system has been built and tested to verify the effectiveness of the proposed strategy.

• Journal of Power Electronics
• /
• v.18 no.3
• /
• pp.931-943
• /
• 2018

Wireless power transfer (WPT) technology has been the focus of a lot of research due to its safety and convenience. The Z-source inverter (ZSI) was introduced into WPT systems to realize improved system performance. The ZSI regulates the dc-rail voltage in WPT systems without front-end converters and makes the inverter bridge immune to shoot-through states. However, when the WPT system is combined with a ZSI, the system parameters must be configured to prevent the ZSI from entering an "accidental shoot-through" (AST) state. This state can increase the THD and decrease system power and efficiency. This paper presents a mathematical analysis for the characteristics of a WPT system and a ZSI while addressing the causes of the AST state. To deal with this issue, the impact of the system parameters on the output are analyzed under two control algorithms and the primary compensation capacitance range is derived in detail. To validate the analysis, both simulations and experiments are carried out and the obtained results are presented.

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

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.36-37
• /
• 2011

본 논문에서는 3상 PWM 인버터와 7가지의 3상 Z-소스 인버터(ZSI)의 효율을 비교 분석하였다. 출력전압을 220Vrms로 하고 듀티비는 0.2로 하였다. 그 결과 3상 PWM 인버터의 효율이 가장 높았으며 PSIM 시뮬레이션을 통해서 효율을 고찰하였다.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.359-360
• /
• 2012

This paper proposes a scheme of auto-tuning fuzzy PI controller and input voltage feed forward to control the output voltage of a three-phase Z-source inverter (ZSI). The proposed scheme adjusts the ts (Kp and Ki) in real time in order to find the most suitable Kp and Ki for PI controller and to simplify the controller design. The proposed scheme is verified the validity by experiment and co-simulation in PSIM and MATLAB/SIMULINK both load step change and input DC voltage variation in Z-source inverter, and has compared with the conventional PID control scheme. The experiment results involve of three-phase output voltage, Z-network capacitor voltage and dc-link peak voltage value. By those analysis and comparison, the availability of the proposed method in output voltage transient response quality improving has been verified. Compared with conventional PID method, the proposed method showed a more effective and robust control performance for coping with the severe disturbance conditions.

• Journal of Power Electronics
• /
• v.15 no.2
• /
• pp.299-308
• /
• 2015

This study proposes four novel pulse width modulation (PWM) shoot-through control methods for impedance source (IS) galvanically isolated DC-DC converters. These methods are derived from a PWM control method with shifted shoot-through introduced by the authors in 2012. In contrast to the baseline solution, where the shoot-through states are generated by the simultaneous conduction of all transistors in the inverter bridge, our new approach is based on the shoot-through generation by one inverter leg. The idea is to increase the number of soft-switched transients and, therefore, decrease the dynamic losses of the front-end inverter. All the proposed approaches are experimentally verified through an insulated-gate bipolar transistor-based IS DC-DC converter. Conclusions are drawn in accordance with the results of the switching loss analysis.

• Proceedings of the KIPE Conference
• /
• 2010.11a
• /
• pp.339-340
• /
• 2010

본 논문에서는 Z-네트워크 커패시터 전압 제어를 위한 변조지수 적분제어를 이용하여 3상 Z-소스 인버터(ZSI)의 출력 교류전압을 일정하게 제어하는 방법을 제안하였다. ZSI의 직류전압 및 부하가 변동되는 상황에서도 제안된 방법을 사용하여 일정한 출력 교류전압을 유지하는 것이 가능하다. 제안된 방법의 타당성을 입증하기 위해 ZSI의 직류전압이 200[V]에서 150[V]로 급감 하는 경우와 부하가 $60[{\Omega}]$에서 $20[{\Omega}]$으로 급감하는 경우를 PSIM 시뮬레이션을 이용해 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.3
• /
• pp.201-210
• /
• 2014

In this paper, dc-link voltage control of a grid-connected QZSI is presented. Since the input current of the ZSI is discontinuous, a capacity with relatively large capacitance should be connected to the output of the PV array in order to reduce the current ripple. Due to the presence of the impedance network inductor in series with the PV array, the QZSI can achieve continuous input current flow. Several dc-link voltage control methods are compared and the method for power quality improvement is also presented. The performance of the proposed method is verified through both simulation and experimental results.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.365-366
• /
• 2010

본 논문에서는 양방향성 Z-소스 DC-DC 컨버터 2대를 이용한 단상 Z-소스 부스트 인버터를 설계하고 분석하였다. 두 대의 컨버터를 이용한 인버터 시스템은 종전의 PWM 인버터 시스템과 달리 두 컨버터에서 출력되는 두 교류 출력을 이용한 것으로 전체 시스템의 교류 출력전압에 포함된 고조파가 낮다. 또한, 컨버터 내부를 구성하는 L-C로 인해 추가적인 출력필터 설계가 불필요 하다는 장점이 있다. 본 연구에서는 종전의 부스트 컨버터 또는 벅-부스트 컨버터 방식이 아닌 두 대의 Z-소스 DC-DC 컨버터를 입력 DC전원과 출력 부하를 공통으로 하는 단상 인버터 시스템을 구성하고, 교류 출력파형 및 제어방법과 동작특성을 분석하였다.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.363-364
• /
• 2010

본 논문에서는 전압형 3상 Z-소스 인버터의 전압 안정화를 위한 새로운 제어방법을 제안하였다. 제안된 방법은 전압형 3상 Z-소스 인버터의 입력전압과 Z-임피던스 망의 커패시터 인가전압을 검출하여 제어하는 방식이다. 검출된 두 전압을 이용해 동작중인 시스템의 전압이득 및 변조지수를 유도하였다. 제안된방법은 전압 안정화를 위한 전압이득 및 변조지수와의 비교연산을 통해 출력전압을 안정화 시키는 방법으로 PISM을 이용하여 출력 교류 파형 및 제어방법을 분석하였다.