Hybrid Current-Mode Control of PSFB Converter to Compensate Slew Interval and Prevent Magnetic Saturation of Transformers

Ko, Jae-Hak; Baek, Seung-Woo; Lee, Kang-Mun; Kim, Hag-Wone; Cho, Kwan-Yul; Kim, Jae-Moon

doi:10.3390/electronics9091395

Cited by 3 publications

(10 citation statements)

References 11 publications

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“…Unfortunately, various inevitable effects can cause a small asymmetrical voltage-second product on primary side of transformer [14]. One transient reason is the unbalanced duty cycle between power cycle PC 1 for the lagging leg and PC 2 for the leading leg due to ZVS-operation or the change of d eff for regulating the output current I B of the PSFB [12]. Even in steady state operation manufacturing tolerances of devices as well as circuit board layout (PCB) cause different voltage drops and apply different voltages to the magnetizing inductor L h and increase I h,DC [10].…”

Section: Transformer Dc-offset Currentmentioning

confidence: 99%

“…Considering bidirectional operation, a blocking capacitor must be placed in series to primary and secondary side of transformer. is method needs several additional power devices compared to controller-based methods and therefore results in increased size of power stage and overall system costs [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…However, the method of gathering the magnetizing current as process variable for a controller differs. [12] extends currentmode control with a hybrid peak and valley current control and does not need for slope compensation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer

Neumann

Meynen

Rahmoun³

et al. 2022

International Transactions on Electrical Energy Systems

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This paper proposes a flexible digital control scheme for isolated phase-shift full-bridge (PSFB) converters. The required transformer suffers from inevitable imbalance of magnetic flux resulting in an increased magnetizing DC-offset current that threatens system reliability due to saturation effects. The paper addresses two major issues of the occurrence of a magnetizing DC-offset current. First, caused by the change of duty cycle due to output power regulation and second caused by initial manufacturer tolerances of devices. In contrast to common methods the novel control scheme uses a Luenberger observer to estimate the magnetizing current requiring only simple measurement of transformer voltages without additional and lossy auxiliary networks. The observer model, in combination with a PI-controller, directly interventions the duty cycle and removes any DC-offset current resulting from both issues. A detailed deviation of the state-space model of the transformer and a subsequently design of the observer are presented. Simulation and experimental results on a PSFB prototype verify the principal functionality of the proposed control scheme to prevent transformer saturation.

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Section: Transformer Dc-offset Currentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer

Neumann

Meynen

Rahmoun³

et al. 2022

International Transactions on Electrical Energy Systems

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“…The current mode control has also been shown to eliminate the flux symmetry problem associated with isolated topologies 9 . As comparison of a number of newest peak current mode control methods, references 3,10,11 are studied. In Ko et al, 10 hybrid current mode control for a phase‐shifted full‐bridge converter is presented, but the effect of sub‐harmonic oscillation on the controller performance and mitigating its effect has not been studied.…”

Section: Introductionmentioning

confidence: 99%

“…As comparison of a number of newest peak current mode control methods, references 3,10,11 are studied. In Ko et al, 10 hybrid current mode control for a phase‐shifted full‐bridge converter is presented, but the effect of sub‐harmonic oscillation on the controller performance and mitigating its effect has not been studied. In Ma et al, 3 secondary‐side peak current mode control on isolated buck forward converter is studied; however, duty cycle greater than 0.5 and its effect on converter stability are not considered.…”

Section: Introductionmentioning

confidence: 99%

Digital peak current mode control of isolated current‐fed push‐pull DC‐DC converter with slope compensation

Ghalebani

Teymoori

2021

Circuit Theory & Apps

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The isolated current‐fed push‐pull dc‐dc converter has some practical advantages such as improved cross regulation characteristics, reduced output noise, and good overall efficiency. Although detailed insight on this converter is available in the literature, the use of digital peak current mode with slope compensation control methodology has not been explicitly presented. This paper discusses digital peak current mode control of a current‐fed push‐pull converter with a novel double digital pulse‐by‐pulse current limiting scheme. Push‐pull topology is implemented on the primary side of an isolation transformer in a dc‐dc bidirectional converter. Achieving this control solution of isolated push‐pull converter is attractive especially in controlling battery power flow in smart micro‐grids. By using a digitally controlled push‐pull converter, the ability to change controller parameters and the use of droop control methods for storage are easier. Furthermore, current mode control provides capability of equal current sharing between parallel converters and eliminates the transformer saturation problem that is common in push‐pull topology. Using continuous time model of the converter, a Type II compensator is designed and implemented in discrete time domain. Digital slope compensation is applied to eliminate the high frequency oscillations caused by current feedback loop. The control method and slope compensation are implemented on STM32F303 mixed‐signal microcontroller. On‐chip analog comparator disabled the PWM output if the sensed current exceeds the reference current until next PWM cycle. The digital controller performance is confirmed by 13 W hardware implementation including fast transient response and stable operation.

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Reactance Regulation Using Coils with Perpendicular Magnetic Field in the Tubular Core design

et al. 2020

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This article presents an efficient method for prosumer connection to the distribution line. The prosumers can be connected to the distribution line using specially designed controllable reactive impedance. The reactive impedance is controlled using specially designed coils and magnetic core. The internal coil is wound in the toroidal direction (across the z-axis) and creates a toroidal shape. A thin ferromagnetic strip is coiled on this toroidal shape in the poloidal direction to form the ferromagnetic core. Then, an external coil is wound on this ferromagnetic core in the poloidal direction. The internal coil is controlled by the inductive impedance of the external coil, which is related to the anisotropic properties of ferromagnetic strips. The internal coil is connected between the power supply line and a prosumer. This arrangement confirms the magnetic independence of coils and the symmetry of the current in the internal coil. The magnetic coupling between both coils is very low (~0.015–0.017) and appropriate for engineering applications. It is approved that the impedance of the internal coil is changed due to the anisotropic magnetic properties of the core material.

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Hybrid Current-Mode Control of PSFB Converter to Compensate Slew Interval and Prevent Magnetic Saturation of Transformers

Cited by 3 publications

References 11 publications

Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer

Controlling Transformer Magnetizing Offset Current in Isolated Phase-Shift Full-Bridge Converters Using a Luenberger Observer

Digital peak current mode control of isolated current‐fed push‐pull DC‐DC converter with slope compensation

Reactance Regulation Using Coils with Perpendicular Magnetic Field in the Tubular Core design

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