Topologies and Control Strategies of Very High Frequency Converters: A Survey

Xu, Dianguo; Guan, Yueshi; Wang, Yijie; Wang, Wei

doi:10.24295/cpsstpea.2017.00004

Cited by 20 publications

(6 citation statements)

References 23 publications

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“…Increasing the operation frequency can reduce the values of inductors and capacitors while maintaining the same voltage and current waveforms. Thus, the energy storage and volume of passive components (inductors and capacitors) are reduced, which provides great potential for a high power density and a fast dynamic response [1][2][3][4]. However, the switching losses increase greatly with the increase of switching frequency, which degrades the overall power efficiency.…”

Section: Introductionmentioning

confidence: 99%

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

et al. 2022

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This paper proposes a fully analytical loss model to reduce circling currents and improve the power efficiency of a class Φ2 inverter. Firstly, analytical expression of the switching node voltage is derived by analyzing its harmonic components. Based on the result, the power switch is modeled as a voltage source, where the circuit is simplified to a linear network and analytical expressions of branch currents are solved. Secondly, root mean square (RMS) values of branch currents and component losses are calculated to form the analytical loss model for a Φ2 inverter. The influence of circuit parameters on the circling current and power efficiency are thoroughly analyzed, which derives optimal design constraints to reduce circling currents of a class Φ2 inverter. Furthermore, detailed design guidance and equations are provided to calculate circuit parameters of a class Φ2 inverter, which reduces its circling currents and improves overall power efficiency. Finally, a class Φ2 inverter prototype is built, and experimental results demonstrate a 7% efficiency improvement compared to conventional empirical design methods.

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Section: Introductionmentioning

confidence: 99%

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

et al. 2022

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“…The buck-type DC-DC converters are used in various applications where the required output voltage is smaller than the input voltage, for example, the computer systems and renewable energy systems [1][2][3]. Since buck converters are characterised as variable structure systems due to their switching operations, sliding mode (SM) control technology has been considered as a suitable non-linear control substitute over the traditional pulse width modulation (PWM) control [4] due to its major advantages such as easy implementation and strong robustness against parameter perturbations and external disturbances [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…The stability is the requirement of SM-controlled buck converters in practical applications. To achieve this aim, various ways have arisen and are summarised in the recent surveys [3,8], for example, an improved circuit topology in [9], a new SMcontrolled strategy in [10] and an observer for estimating the unknown load resistors in [11]. Except for these common factors affecting the stability and control performance of buck converters mentioned in [5,[9][10][11], special attention should be paid to some unmodelled dynamics.…”

Section: Introductionmentioning

confidence: 99%

Stability of sliding mode controlled buck converters with unmodelled dynamics of circuit elements and hall sensor

Wang

Niu

Yang

et al. 2021

IET Power Electronics

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This paper investigates the stability problem of sliding mode controlled buck converters affected by unmodelled dynamics of circuit elements and Hall sensor. The parasitic resistors of all elements are contained in the modelling of buck converters. Different from the traditional sliding mode approach based on the nominal model, the circuit parasitic parameters are directly included in the controller design and stability analysis, which divide the regulation region located in the right half axis into four sub‐ranges. It is more accurate and has no need of extra compensator. For Hall sensor, singular perturbation theory is adopted for modelling and analysing, giving a stable condition concerning its dynamic and static parameters. Finally, the influence of the two types of unmodelled dynamics on the whole closed‐loop system is investigated by constructing an equivalent model, giving a more strict stability condition. Simulations and experiments are presented to illustrate the non‐negligible influence of these unmodelled dynamics.

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“…Furthermore, reverse conduction time in conditions [14], where the drain voltage of main power switch deviates as the load or input voltage varies. Since a fixed driving signal is usually used to control the power switch [15][16][17][18], the reverse conduction time often increases by the deviated drain voltage, leading to higher losses.…”

Section: Introductionmentioning

confidence: 99%

Linear Equivalent Model for VHF Class Φ₂ Inverter Based on Spectrum Quantification Method to Reduce GaN Reverse Conduction Loss

et al. 2021

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Reverse conduction loss of GaN high electron mobility transistors (HEMTs) in very high frequency (VHF) converters is non-neglectable due to the absence of body diode. To reduce the reverse conduction time, this paper proposes a linear equivalent model for class Φ2 inverter to derive optimal duty cycles for different working conditions. The proposed model is derived from frequency-domain perspective, which simplifies the derivation process and provides an intuitive physical insight for class Φ2 inverter. Firstly, the power switch is modeled as a current source according to time-domain expressions of inductor current, which simplifies the circuit to a linear network. Based on quantitative analysis of the current source spectrum characteristics, the linear network response to the current excitation is derived, which forms the linear equivalent model. Then, drain voltage of the main switch under different working conditions is obtained. With the zero-crossing point of the drain voltage, numerical solutions of the optimal duty cycles are calculated. Finally, the optimal duty cycles are implemented with a high-resolution duty cycle generation circuit in a 27.12MHz prototype, which achieves not only a peak efficiency of 93.6% at full load, but also higher efficiency over the whole load and input voltage range compared to conventional fixed duty cycle.

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Topologies and Control Strategies of Very High Frequency Converters: A Survey

Cited by 20 publications

References 23 publications

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

Stability of sliding mode controlled buck converters with unmodelled dynamics of circuit elements and hall sensor

Linear Equivalent Model for VHF Class Φ₂ Inverter Based on Spectrum Quantification Method to Reduce GaN Reverse Conduction Loss

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Topologies and Control Strategies of Very High Frequency Converters: A Survey

Cited by 20 publications

References 23 publications

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

Reducing Circling Currents in a VHF Class Φ2 Inverter Based on a Fully Analytical Loss Model

Stability of sliding mode controlled buck converters with unmodelled dynamics of circuit elements and hall sensor

Linear Equivalent Model for VHF Class Φ2 Inverter Based on Spectrum Quantification Method to Reduce GaN Reverse Conduction Loss

Contact Info

Product

Resources

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Linear Equivalent Model for VHF Class Φ₂ Inverter Based on Spectrum Quantification Method to Reduce GaN Reverse Conduction Loss