Jingying Hu

Bio: Jingying Hu is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Integrating ADC & Buck–boost converter. The author has an hindex of 3, co-authored 4 publications receiving 563 citations.

Opportunities and Challenges in Very High Frequency Power Conversion

Abstract: THIS paper explores opportunities and challenges in power conversion in the VHF frequency range of 30-300 MHz. The scaling of magnetic component size with frequency is investigated, and it is shown that substantial miniaturization is possible with increased frequencies even considering material and heat transfer limitations. Likewise, dramatic frequency increases are possible with existing and emerging semiconductor devices, but necessitate circuit designs that either compensate for or utilize device parasitics. We outline the characteristics of topologies and control methods that can meet the requirements of VHF power conversion, and present supporting examples from power converters operating at frequencies of up to 110 MHz.

High-Frequency Resonant SEPIC Converter With Wide Input and Output Voltage Ranges

Abstract: This paper presents a resonant single-ended-primary-inductor-converter (SEPIC) converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design provides high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented that provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an ON-OFF control scheme modulating at a fixed frequency (170 kHz). This control method enables fast transient response and efficient light-load operation while providing controlled spectral characteristics of the input and output waveforms. A hysteretic override technique is also introduced which enables the converter to reject load disturbances with a bandwidth much greater than the modulation frequency, limiting output voltage disturbances to within a fixed value. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6-7.2 V, an output voltage range of 3-9 V, and an output power rating of up to 3 W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage and maintains good efficiency across the whole operating range.

High frequency resonant SEPIC converter with wide input and output voltage ranges

Abstract: This document presents a resonant SEPIC converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design features high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented which provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an on-off control scheme modulating at a fixed frequency. This control method enables fast transient response and efficient light load operation while providing controlled spectral characteristics of the input and output waveforms. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6 V to 7.2 V, an output voltage range of 3 V to 9 V and an output power rating of up to 3 W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage, and maintains good efficiency across the whole operating range.

Ant Colony Optimized Tuned DC-DC Converter

Abstract: Ant Colony Optimization (ACO) used to tune the Proportional and Integral (PI) controller for Single Ended Primary Inductance Converter (SEPIC) is discussed in this paper. The SEPIC is based on DC to DC converter to maintain the constant output voltage but varying input voltage. PI controller maintains a constant output of the converter, without changing sign. MATLAB simulation designing is developed for ACO tuned DC-DC converter.

Overview of Planar Magnetic Technology—Fundamental Properties

Abstract: The momentum toward high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic components This paper gives an overview of planar magnetic technologies with respect to the development of modern power electronics The major advantages and disadvantages in the use of planar magnetics for high-frequency power converters are covered, and publications on planar magnetics are reviewed A detailed survey of winding conduction loss, leakage inductance, and winding capacitance for planar magnetics is presented so power electronics engineers and researchers can have a clear understanding of the intrinsic properties of planar magnetics

Measurements and performance factor comparisons of magnetic materials at high frequency

Abstract: The design of power magnetic components for operation at high frequency (HF, 3–30 MHz) has been hindered by a lack of magnetic material performance data and by the limited design theory in that frequency range. To address these deficiencies, we have measured and present core loss data for a variety of commercially available magnetic materials in the HF range. In addition, we extend the theory of performance factor for appropriate use in the HF design. Since magnetic materials suitable for HF applications tend to have low permeability, we also consider the impact of low permeability on design. We conclude that, with appropriate material selection and design, increased frequencies can continue to yield improved power density well into the HF regime.

A very high frequency dc-dc converter based on a class Φ 2 resonant inverter

Abstract: This paper introduces a new dc-dc converter suitable for operation at very high frequencies under on-off control. The converter power stage is based on a resonant inverter (the Phi2 inverter) providing low switch voltage stress and fast settling time. A new multi-stage resonant gate driver suited for driving large, high-voltage rf MOSFETS at VHF frequencies is also introduced. Experimental results are presented from a prototype dc-dc converter operating at 30 MHz at input voltages up to 200 V and power levels above 200 W. These results demonstrate the high performance achievable with the proposed design.

Evaluation of Magnetic Materials for Very High Frequency Power Applications

Abstract: This paper investigates the loss characteristics of RF magnetic materials for power conversion applications in the 10 to 100 MHz range. A measurement method is proposed that provides a direct measurement of an inductor quality factor QL as a function of inductor current at RF frequencies, and enables indirect calculation of core loss as a function of flux density. Possible sources of error in measurement and calculation are evaluated and addressed. The proposed method is used to identify loss characteristics of several commercial RF magnetic-core materials. The loss characteristics of these materials, which have not previously been available, are illustrated and compared in tables and figures. The use of the method and data is demonstrated in the design of a magnetic-core inductor, which is applied in a 30-MHz inverter. The results of this paper are thus useful for the design of magnetic components for very high frequency applications.

High-Frequency Resonant SEPIC Converter With Wide Input and Output Voltage Ranges

Abstract: This paper presents a resonant single-ended-primary-inductor-converter (SEPIC) converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design provides high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented that provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an ON-OFF control scheme modulating at a fixed frequency (170 kHz). This control method enables fast transient response and efficient light-load operation while providing controlled spectral characteristics of the input and output waveforms. A hysteretic override technique is also introduced which enables the converter to reject load disturbances with a bandwidth much greater than the modulation frequency, limiting output voltage disturbances to within a fixed value. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6-7.2 V, an output voltage range of 3-9 V, and an output power rating of up to 3 W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage and maintains good efficiency across the whole operating range.