• Title/Summary/Keyword: High step-up Ratio

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High Step-Up Converter with Hybrid Structure Based on One Switch

  • Hwu, K.I.;Peng, T.J.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1566-1577
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    • 2015
  • A novel high step-up converter is presented herein, which combines the conventional buck-boost converter, the charge pump capacitor and the coupling inductor. By doing so, a quite high voltage conversion ratio due to not only the turns ratio but also the duty cycle, so as to increase design feasibility. It is noted that the denominator of the voltage conversion ratio is the square of one minus duty cycle. Above all, there is no voltage spike across the switch due to the leakage inductance and hence no passive or active snubber is needed, and furthermore, the used switch is driven without isolation and hence the gate driving circuit is relatively simple, thereby upgrading the industrial application capability of this converter. In this paper, the basic operating principles and the associated mathematical deductions are firstly described in detail, and finally some experimental results are provided to demonstrate the effectiveness of the proposed high step-up converter.

Measurement Range Extension of AC High Voltage using two 200 kV Capacitive Dividers (200 kV 용량형 분압기 2대를 이용한 교류 고전압 측정범위 확장)

  • Jung, Jae-Kap;Lee, Sang-Hwa;Kang, Jeon-Hong;Kim, Myung-Soo;Kim, Yoon-Hyoung;Han, Sang-Gil;Jeong, Jin-Hye;Han, Sang-Ok;Joung, Jong-Man
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.1
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    • pp.1-5
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    • 2008
  • The output voltage value of AC high voltage source has been usually obtained by multiplying low voltage value measured at both terminals of low voltage resistor by the dividing ratio of the high voltage capacitive divider. From the dividing ratio determined of each 200 kV capacitive divider, we have developed step-up method for measuring the output voltage up to 400 kV using two same type of 200 kV capacitive dividers connected in series. The theoretical dividing ratio of 400 kV capacitive dividers connected in series coincides with that of manufacturer's certification within measurement uncertainty. Thus, this developed step-up method makes it possible to extend the range of output voltage from 200 kV to 400 kV. Furthermore, The dividing ratio of divider under test obtained using this step-up method is consistent with that obtained using one 200 kV high voltage divider within corresponding uncertainties.

Single-Ended High-Efficiency Step-up Converter Using the Isolated Switched-Capacitor Cell

  • Kim, Do-Hyun;Jang, Jong-Ho;Park, Joung-Hu;Kim, Jung-Won
    • Journal of Power Electronics
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    • v.13 no.5
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    • pp.766-778
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    • 2013
  • The depletion of natural resources and renewable energy sources, such as photovoltaic (PV) energy, has been highlighted for global energy solution. The PV power control unit in the PV power-generation technology requires a high step-up DC-DC converter. The conventional step-up DC-DC converter has low efficiency and limited step-up ratio. To overcome these problems, a novel high step-up DC-DC converter using an isolated switched capacitor cell is proposed. The step-up converter uses the proposed transformer and employs the switched-capacitor cell to enable integration with the boost inductor. The output of the boost converter and isolated switched-capacitor cell are connected in series to obtain high step-up with low turn-on ratio. A hardware prototype with 30 V to 40 V input voltage and 340 V output voltage is implemented to verify the performance of the proposed converter. As an extended version, another novel high step-up isolated switched-capacitor single-ended DC-DC converter integrated with a tapped-inductor (TI) boost converter is proposed. The TI boost converter and isolated-switched-capacitor outputs are connected in series to achieve high step-up. All magnetic components are integrated in a single magnetic core to lower costs. A prototype hardware with 20 V to 40 V input voltage, 340 V output voltage, and 100 W output power is implemented to verify the performance of the proposed converter.

High Efficiency High-Step-up Single-ended DC-DC Converter with Small Output Voltage Ripple

  • Kim, Do-Hyun;Kim, Hyun-Woo;Park, Joung-Hu;Jeon, Hee-Jong
    • Journal of Power Electronics
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    • v.15 no.6
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    • pp.1468-1479
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    • 2015
  • Renewable energy resources such as wind and photovoltaic power generation systems demand a high step-up DC-DC converters to convert the low voltage to commercial grid voltage. However, the high step-up converter using a transformer has limitations of high voltage stresses of switches and diodes when the transformer winding ratio increases. Accordingly, conventional studies have been applied to series-connect multioutput converters such as forward-flyback and switched-capacitor flyback to reduce the transformer winding ratio. This paper proposes new single-ended converter topologies of an isolation type and a non-isolation type to improve power efficiency, cost-effectiveness, and output ripple. The first proposal is an isolation-type charge-pump switched-capacitor flyback converter that includes an extreme-ratio isolation switched-capacitor cell with a chargepump circuit. It reduces the transformer winding number and the output ripple, and further improves power efficiency without any cost increase. The next proposal is a non-isolation charge-pump switched-capacitor-flyback tapped-inductor boost converter, which adds a charge-pump-connected flyback circuit to the conventional switched-capacitor boost converter to improve the power efficiency and to reduce the efficiency degradation from the input variation. In this paper, the operation principle of the proposed scheme is presented with the experimental results of the 100 W DC-DC converter for verification.

Symmetrical Cockcroft-Walton circuit for Transformerless High Step-Up DC-DC Converter (변압기 없는 고승압 직류 컨버터용 대칭형 Cockcroft-Walton 회로)

  • Cha, Dae-Joong;Baek, Ji-Eun;Ko, Kwang-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.8
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    • pp.70-75
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    • 2015
  • High Step-up DC-DC Converters have been demanded for renewable energy applications. Transformer or coupled inductor is generally used to boost output voltage of converters. This methods can relatively obtain high voltage than others, whereas have heavy weight and high cost. To complement these disadvantages, we studied transformerless high step-up DC-DC converter. In various transformerless topologies, Boost converters combined with Cockcroft-Walton have studied. In this paper, we proposed a symmetrical Cockcroft-Walton circuit for transformerless high step-up DC-DC converter. Finally, we simulated proposed converter to compare with existing converter. As a result, proposed converter has higher duty ratio or lower cost than existing transformerless converters which are discussed in this paper.

Analysis and Implementation of High Step-Up DC/DC Convertor with Modified Super-Lift Technique

  • Fani, Rezvan;Farshidi, Ebrahim;Adib, Ehsan;Kosarian, Abdolnabi
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.645-654
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    • 2019
  • In this paper, a new high step up DC/DC converter with a modified super-lift technique is presented. The coupled inductor technique is combined with the super-lift technique to provide a tenfold or more voltage gain with a proper duty cycle and a low turn ratio. Due to a high conversion ratio, the voltage stress on the semiconductor devices is reduced. As a result, low voltage ultra-fast recovery diodes and low on resistance MOSFET can be used, which improves the reverse recovery problems and conduction losses. This converter employs a passive clamp circuit to recycle the energy stored in the leakage inductance. The proposed convertor features a high conversion ratio with a low turn ratio, low voltage stress, low reverse recovery losses, omission of the inrush currents of the switch capacitor loops, high efficiency, small volume and reduced cost. This converter is suitable for renewable energy applications. The operational principle and a steady-state analysis of the proposed converter are presented in details. A 200W, 30V input, 380V output laboratory prototype circuit is implemented to confirm the theoretical analysis.

A High-Efficiency High-Power Step-Up Converter with Low Ripple Content

  • Kang Jeong-il;Roh Chung-Wook;Moon Gun-Woo;Youn Myung-Joong
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.708-712
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    • 2001
  • A new phase-shifted parallel-input/series-output (PI SO) dual inductor-fed push-pull converter for high-power step­up applications is proposed. This converter is operated at a constant duty cycle and employs an auxiliary circuit to control the output voltage with a phase-shift between the two modules. It features a voltage conversion characteristic which is linear to changes in the control input, and high step-up ratio with a greatly reduced switch turn-off stress resulting in a significant increase in the converter efficiency. It also shows a low ripple content and low root-mean-square (RMS) current in the output capacitor. The operational principle is analyzed and a comparative analysis with the conventional pulse-width-modulated (PWM) PISO dual inductor-fed push-pull converter is presented. A 50kHz, 800W, 350Vdc prototype with an input of 20-32Vdc has also been constructed to validate the proposed converter. The proposed converter compares favorably with the conventional counterpart and is considered well suited to high-power step-up applications.

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An Efficient and High-gain Inverter Based on The 3S Inverter Employs Model Predictive Control for PV Applications

  • Abdel-Rahim, Omar;Funato, Hirohito;Junnosuke, Haruna
    • Journal of Electrical Engineering and Technology
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    • v.12 no.4
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    • pp.1484-1494
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    • 2017
  • We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

Electrical Characteristics of Disk-type Piezoelectric Transformer Poled with the Same Direction (동일 방향으로 분극된 디스크형 압전변압기의 전기적 특성)

  • 이종필;홍진웅
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.8
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    • pp.688-692
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    • 2003
  • For high voltage operation, a new type of piezoelectric transformer using radial vibration of disk, poled with the same direction was proposed. The piezoelectric ceramics was composed to PZT-PMN-PSN. The diameter and thickness of a disk type piezoelectric transformer were 45[mm]and 4[mm], respectively The surface ratio of driving electrode and generating electrode of the piezoelectric transformer was 2 : 1. The resonance characteristics of input admittance, step-up voltage ratio and power transmission efficiency of the piezoelectric transformer were measured by varying the load resistance(0.1∼70[kΩ]). As a result, both resonance frequency and step-up voltage ratio increased with increasing load resistance. The step-up voltage ratio was reached more than 60 times under no load resistance. The maximum efficiency of 97% at load resistance of 2kΩ was obtained.

A High-Power Step-up Converter with High Efficiency and Fast Control-to-Output Dynamics

  • Kang, Jeong-il;Roh, Chung-Wook;Moon, Gun-Woo;Youn, Myung-Joong
    • Journal of Power Electronics
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    • v.1 no.2
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    • pp.78-87
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    • 2001
  • A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.

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