• Title, Summary, Keyword: AC/DC converter

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A CMOS Interface Circuit for Vibrational Energy Harvesting (진동에너지 수확을 위한 CMOS 인터페이스 회로)

  • Yang, Min-jae;Yoon, Eun-jung;Yu, Chong-gun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.267-270
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    • 2014
  • This paper presents a CMOS interface circuit for vibration energy harvesting. The proposed circuit consists of an AC-DC converter and a DC-DC boost converter. The AC-DC converter rectifies the AC signals from vibration devices(PZT), and the DC-DC boost converter generates a boosted and regulated output at a predefined level. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a schottky diode type DC-DC boost converter is used for a simple control circuitry. A MPPT(Maximum Power Point Tracking) control is also employed to harvest the maximum power from the PZT. The proposed circuit has been designed in a 0.35um CMOS process. The chip area is $530um{\times}325um$. Simulation results shows that the maximum efficiencies of the AC-DC converter and DC-DC boost converter are 97.7% and 89.2%, respectively. The maximum efficiency of the entire system is 87.2%.

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Switched Inductor Z-Source AC-DC Converter

  • Sedaghati, Farzad;Hosseini, Seyed Hossein;Sarhangzadeh, Mitra
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.1
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    • pp.67-76
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    • 2012
  • Due to the increasing amount of applications of power electronic ac-dc converters, it is necessary to design a single-stage converter that can reliably perform both buck and boost operations. Traditionally, this can be achieved by double-stage conversion (ac/dc-dc/dc) which ultimately leads to less efficiency and a more complex control system. This paper discusses two types of modern ac-dc converters. First, the novel impedance-source ac-dc converter, abbreviated as custom Z-source rectifier, is analyzed; and then, switched inductor (SL) Z-source ac-dc converter is proposed. This paper describes the Z-source rectifiers' operating principles, the concepts behind them, and their superiorities. Analysis and simulation results show that the proposed custom Z-source rectifier can step up and step down voltage; and the main advantage of the SL Z-source ac-dc converter is its high step-up capability. Low ripple of the output dc voltage is the other advantage of the proposed converters. Finally, the SL Z-source ac-dc converter is compared with the custom Z-source ac-dc converter.

High Power Factor 3-Phase AC-DC Converter without LC Filter (LC필터가 없는 고역율 3상 AC-DC 컨버터)

  • Nam, Jing-Rak
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.10
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    • pp.1894-1898
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    • 2007
  • Conventional 3-phase AC-DC converter is frequently in the industrial world. In this paper, the high power factor 3-phase AC-DC converter which can reduce its weight and volume is proposed. The high power factor 3-phase AC-DC converter without LC filter can realize light weight and low-cost. In spite of elimination of LC filter, the performance of the high power 3-phase AC-DC converter is almost the same as conventional 3-phase AC-DC converter. Finally, this result can be expected to be applied to aviation and the space industry with high power density and high power factor.

Modeling and Control of a Two-Stage DC-DC-AC Converter for Battery Energy Storage System (배터리 에너지 저장 장치를 위한 2단 DC-DC-AC 컨버터의 모델링 방법)

  • Hyun, Dong-Yub;Jung, Seok-Eon;Hyun, Dong-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.5
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    • pp.422-430
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    • 2014
  • This study proposes a small-signal model and control design for a two-stage DC-DC-AC converter to investigate its dynamic characteristics in relation to battery energy storage system. When the circuit analysis of the two-stage DC-DC-AC converter is attempted simultaneously, the mathematical procedure of deriving the dynamic equation is complex and difficult. The main idea of modeling the two-stage DC-DC-AC converter states that this topology is separated into a bidirectional DC-DC converter and a single-phase inverter with an equivalent current source corresponding to that of the inverter or converter. The dynamic equations for the separated converter and inverter are then derived using the state-space averaging technique. The procedures of building the small-signal model of the two-stage DC-DC-AC converter are described in detail. Based on the derived small-signal model, the individual controllers are designed through a frequency-domain analysis. The simulation and experimental results verify the validity of the proposed modeling approach and controller design.

Wireless Energy Transmission High-Efficiency DC-AC Converter Using High-Gain High-Efficiency Two-Stage Class-E Power Amplifier

  • Choi, Jae-Won;Seo, Chul-Hun
    • Journal of electromagnetic engineering and science
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    • v.11 no.3
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    • pp.161-165
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    • 2011
  • In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.

Diagnosis Methods for IGBT Open Switch Fault Applied to 3-Phase AC/DC PWM Converter

  • Im, Won-Sang;Kim, Jang-Sik;Kim, Jang-Mok;Lee, Dong-Choon;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.120-127
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    • 2012
  • Fault diagnosis technique of electrical drives is becoming more and more important, since voltage fed converter system has become industrial standard in many applications. Many studies have been conducted an inverter fault diagnosis for induction motors. However, there are few researches about fault diagnosis of 3-phase ac/dc PWM (Pulse Width Modulation) converter compared to the dc/ ac inverter. The ac/dc converter is the opposite of dc/ac inverter at current flow. Also, inverter and converter have different current patterns under the same condition of IGBT (Insulated gate bipolar transistor) open switch fault. Therefore, it is difficult to apply intact diagnosis methods of inverter to the converter. This paper proposes modified fault detection methods for IGBT open switch fault in 3-phase ac/dc PWM converter by modifying established fault diagnostic methods for dc/ac inverters.

Two-Switch Auxiliary Resonant DC Link Snubber-Assisted Three-Phase Soft Switching PWM Sinewave Power Conversion System with Minimized Commutation Power Losses

  • Nagai, Shinichiro;Sato, Shinji;Ahmed, Tarek;Nakaoka, Mutsuo
    • Journal of Power Electronics
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    • v.3 no.4
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    • pp.249-258
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    • 2003
  • This paper presents a high-efficient and cost effective three-phase AC/DC-DC/AC power conversion system with a single two-switch type active Auxiliary Resonant DC Link (ARDCL) snubber circuit, which can minimize the total power dissipation. The active ARDCL snubber circuit is proposed in this paper and its unique features are described. Its operation principle in steady-state is discussed for the three phase AC/DC-DC/AC converter, which is composed of PWM rectifier as power factor correction (PFC) converter, sinewave PWM inverter. In the presented power converter system not only three-phase AC/DC PWM rectifier but also three-phase DC/AC inverter can achieve the stable ZVS commutation for all the power semiconductor devices. It is proved that the proposed three-phase AC/DC-DC/AC converter system is more effective and acceptable than the previous from the cost viewpoint and high efficient consideration. In addition, the proposed two-switch type active auxiliary ARDCL snubber circuit can reduce the peak value of the resonant inductor injection current in order to maximize total system actual efficiency by using the improved DSP based control scheme. Moreover the proposed active auxiliary two-switch ARDCL snubber circuit has the merit so that there is no need to use any sensing devices to detect the voltage and current in the ARDCL sunbber circuit for realizing soft-switching operation. This three-phase AC/DC-DC/AC converter system developed for UPS can achieve the 1.8% higher efficiency and 20dB lower conduction noise than those of the conventional three-phase hard-switching PWM AC/DC-DC/AC converter system. It is proved that actual efficiency of the proposed three-phase AC/DC-DC/AC converter system operating under a condition of soft switching is 88.7% under 10kw output power.

A CMOS Interface Circuit with MPPT Control for Vibrational Energy Harvesting (진동에너지 수확을 위한 MPPT 제어 기능을 갖는 CMOS 인터페이스 회로)

  • Yang, Min-jae;Yoon, Eun-jung;Yu, Chong-gun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.412-415
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    • 2015
  • This paper presents a MPPT(Maximum Power Point Tracking) control CMOS interface circuit for vibration energy harvesting. The proposed circuit consists of an AC-DC converter, MPPT Controller, DC-DC boost converter and PMU(Power Management Unit). The AC-DC converter rectifies the AC signals from vibration devices(PZT). MPPT controller is employed to harvest the maximum power from the PZT and increase efficiency of overall system. The DC-DC boost converter generates a boosted and regulated output at a predefined level and provides energy to load using PMU. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a schottky diode type DC-DC boost converter is used for a simple control circuitry. The proposed circuit has been designed in a 0.35um CMOS process. The chip area is $950um{\times}920um$.

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An 18-Pulse Full-Wave AC-DC Converter for Power Quality Improvement

  • Singh, Bhim;Gairola, Sanjay
    • Journal of Power Electronics
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    • v.8 no.2
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    • pp.109-120
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    • 2008
  • In this paper, a novel delta/double-fork transformer based 18-pulse full-wave AC-DC converter is designed, modeled, simulated and developed to feed isolated DC varying loads. The proposed AC-DC converter is used for low voltage and large current DC loads in applications such as electrowinning, where isolation is required mainly for stepping down the supply voltage. The proposed converter improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.

A New Waveshaper for Harmonic Mitigation in Vector Controlled Induction Motor Drives

  • Singh, Bhim;Garg, Vipin;Bhuvaneshwari, G.
    • Journal of Electrical Engineering and Technology
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    • v.3 no.2
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    • pp.152-161
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    • 2008
  • This paper deals with a new wave shaping technique for cost effective harmonic mitigation in ac-dc converter feeding Vector Controlled Induction Motor Drives(VCIMD's) for improving power quality at the point of common coupling(PCC). The proposed harmonic mitigator consists of a polygon connected autotransformer based twelve-pulse ac-dc converter and a small rating passive shunt filter tuned for $11^{th}$ harmonic frequency. This ac-dc converter eliminates the most dominant $5^{th},\;7^{th},\;and\;11^{th}$ harmonics and imposes the reduction of other higher order harmonics from the ac main current, thereby improving the power quality at ac mains. The design of autotransformer is carried out for the proposed ac-dc converter to make it suitable for retrofit applications, where presently a 6-pulse ac-dc converter is used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed ac-dc converter in a wide operating range of the drive. Experimental results obtained on the developed laboratory prototype of the proposed harmonic mitigator are used to validate the model and design of the ac-dc converter.