A Very High Efficiency Circuit Topology for a Few kW Inverter Based on Partial Power Conversion Principle

Kawamura, Atsuo; Nagai, Sakahisa; Nakazaki, Satoshi; Ito, Shotaro; Obara, Hidemine

doi:10.1109/ecce.2018.8558317

Cited by 9 publications

(22 citation statements)

References 11 publications

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“…2-a-p ) ave(PLtotal) ave(ε1AC)-ave(ε1DC), ..... (21) where "ave" denotes averaging. From (18), the following equation is derived.…”

Section: Derivation Of Average Efficiency and Accuracy Of Vtaslm Methodsmentioning

confidence: 99%

“…The HEECS inverter (8,18) was selected as a converter under test, and the measurement was performed following the procedure described in Section 2.6. The measurement instruments listed in Appendix 1 were preheated before the measurements, and all the equipment were installed in a constant temperature chamber (8) for measurement.…”

Section: Loss Measurement and The Efficiency Calculationmentioning

confidence: 99%

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Proposal of Virtual Transformer-based Back-to-Back Asynchronous Loss Measurement using a Single Set of Measurement Instruments for One Inverter and Experimental Verification

et al. 2022

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In this study, a virtual transformer-based loss measurement method is proposed for inverter power conversion efficiency measurements, and the accuracy of this method is theoretically analyzed. This concept is further extended to a practical measurement procedure, wherein asynchronous loss measurements are conducted for powering and regenerating operations using a single set of measurement instruments. The average efficiency can be obtained with a very high accuracy after calibration of the measurement instruments. A high-efficiency system inverter was selected as the converter under test, and its efficiency and accuracy were experimentally measured and validated. An efficiency of 99.75% ± 0.006% was obtained at an output of 1600 W.

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“…2-a-p ) ave(PLtotal) ave(ε1AC)-ave(ε1DC), ..... (21) where "ave" denotes averaging. From (18), the following equation is derived.…”

Section: Derivation Of Average Efficiency and Accuracy Of Vtaslm Methodsmentioning

confidence: 99%

Section: Loss Measurement and The Efficiency Calculationmentioning

confidence: 99%

Proposal of Virtual Transformer-based Back-to-Back Asynchronous Loss Measurement using a Single Set of Measurement Instruments for One Inverter and Experimental Verification

et al. 2022

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“…The use of unfolding inverters with low switching loss has received considerable attention [4][5][6][7] with the purpose of realizing such converters with low total loss. In general, a tradeoff exists between conduction and switching losses as characteristics of semiconductor switching devices.…”

Section: Introductionmentioning

confidence: 99%

“…For further loss reduction, non-isolated (transformer-less) dc/dc converters have been used, and various topologies can be employed in this approach. Other prominent approaches that have been proposed are: Zhao et al [4] used boost-buck converters; Husev et al [5] employed buck-boost converters; Lei et al [33] employed a 7-level converter; and Kawamura et al [6,20] proposed a new multi-level chopper, called HEECS (high efficiency energy conversion system) circuit topology, and a high efficiency of 99.75% was reported in [7, Control Scheme for Leading Power Factor Operation of Single-Phase Grid-Connected…”

Section: Introductionmentioning

confidence: 99%

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Control Scheme for Leading Power Factor Operation of Single-Phase Grid-Connected Inverter Using an Unfolding Circuit

Miguchi

Setiadi

Nasu

et al. 2022

IEEE Open J. Power Electron.

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A single-phase grid-connected inverter with an unfolding circuit consists of a first-stage dc/dc converter, which generates fully rectified sinusoidal waveforms, and a second-stage unfolding inverter, which switches every 180° of line frequency waveform. This converter exhibits low switching loss and high efficiency. Digitally controlled unfolding inverters can be used in numerous applications, such as power supplies to resistive loads and single-phase grid-connected inverters. The operating principle of an unfolding inverter is typically synchronous voltage and current. However, a reactive power supply function with a leading power factor (pf) (lagging pf from the grid perspective) is typically required for grid-connected inverters to suppress the terminal overvoltage. Limited studies have been focused on the operation of inverters with pf less than unity. Such an operation results in large overshoot and oscillation in the output voltage because of the difficulty in coping with large current fluctuations after voltage zero crossing. To this end, we propose a novel control scheme that enables leading pf operation without additional circuitry and overcomes the aforementioned limitations. When the unfolding inverter is operated with leading pf, a special mode called "allconduction mode" occurs after voltage zero crossing. The proposed scheme implements appropriate dc current control to terminate this mode, resulting in a smooth transition to the normal mode steady state with pf less than unity. The scheme verifiably showcases exceptional efficiency in the conducted simulations and experiments.

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Survey of 99.9% Class EfficiencyDC‐ACPower Conversion and Technical Issues

Kawamura

Miguchi

Setiadi

et al. 2022

IEEJ Transactions Elec Engng

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This study provides a survey overview of the literatures with the goal of maximizing the efficiency of DC-AC power conversion from an engineering science perspective. With the advent of wide band gap power semiconductors, the published literature on realizing high efficiency DC-AC converters has increased. Therefore, a literature survey of high-efficiency DC-AC inverters was first conducted. We demonstrated the importance of the measurement accuracy in measuring high efficiency losses, and then presented the literature on new measurement methods, as well as examples of analysis of the breakdown of these losses. Furthermore, we reviewed the literature on high-efficiency inverters. We presented measurement data (99.83%) on an inverter with a high efficiency energy conversion system circuit topology using Silicon Carbide (SiC) and Gallium Nitride (GaN) devices to demonstrate how the procedure was used to achieve loss minimization. We summarized the challenges hindering high efficiency.

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A Very High Efficiency Circuit Topology for a Few kW Inverter Based on Partial Power Conversion Principle

Cited by 9 publications

References 11 publications

Proposal of Virtual Transformer-based Back-to-Back Asynchronous Loss Measurement using a Single Set of Measurement Instruments for One Inverter and Experimental Verification

Proposal of Virtual Transformer-based Back-to-Back Asynchronous Loss Measurement using a Single Set of Measurement Instruments for One Inverter and Experimental Verification

Control Scheme for Leading Power Factor Operation of Single-Phase Grid-Connected Inverter Using an Unfolding Circuit

Survey of 99.9% Class EfficiencyDC‐ACPower Conversion and Technical Issues

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