Effect of parasitics in high voltage bipolar flyback converter for lightly loaded resistive loads
01 Aug 2017-pp 1-6
TL;DR: In this paper, two circuit configurations are proposed to obtain the bipolar output voltage from a high voltage flyback for lightly loaded circuits, and the operational similarities and the advantages/limitations of the two configurations are presented.
Abstract: In high voltage (HV) flyback charging circuits, the importance of transformer parasitics holds a significant part in the overall system parasitics. The resonance between magnetising inductance and resonant capacitance cause significant deviations in voltage gain. This effect is predominant in the case of very lightly loaded high voltage flyback converters when used for bipolar output voltages. In this paper, two circuit configurations are proposed to obtain the bipolar output voltage from a high voltage(HV) flyback for lightly loaded circuits. The operational similarities and the advantages/limitations of the two configurations are presented. The effect of transformer winding capacitance on the achievable gain in a bipolar operation is analysed in both the approaches. The analysis is verified in simulation and hardware implementation for high voltage bipolar flyback converters with valley mode switching to achieve minimum switching loss and device stress.
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01 Jun 2018
TL;DR: A modular circuit structure to generate bipolar high voltage pulses from a low voltage battery source using two bidirectional flyback converter modules connected in differential manner to achieve pulses of opposite polarities respectively is presented.
Abstract: This paper presents a modular circuit structure to generate bipolar high voltage pulses from a low voltage battery source Smart material based actuators and ion analysers require bipolar high voltage output in the range of ± 1 kV to 3 kV for their effective operation In this paper, two bidirectional flyback converter modules are connected in differential manner to achieve pulses of opposite polarities respectively Dedicated CPLD control cards are designed to govern the operation of individual module Each module operate with a two loop control scheme where inner loop detects Minimum Voltage Point (MVP turn on) and output loop controls the peak charging current The modules operate in a phase shifted manner with control signals communicated between the individual controllers to ensure module level coordination An experimental prototype fed from 12 V input is designed and control scheme is implemented to obtain ± 25 kV bipolar output voltage The experimental results observed are in good concordance with the simulation results
2 citations
References
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01 Jun 1978
TL;DR: In this paper, the authors present a theoretical analysis of transformer-inductor design, including the following: AC Inductor Design Powder Core. DC Inductor design Gap Core. Forward Converter Transformer and Inductor Development.
Abstract: Fundamentals of Magnetics. Magnetic Materials and Their Characteristics. Magnetic Cores, Iron Alloy and Ferrites. Window Utilization and Magnet Wire. Transformer-Inductor Design. Transformer-Inductor Efficiency, Regulation, and Temperature Rise. Power Transformer Design. DC Inductor Design Gap Core. DC Inductor Design Powder Core. AC Inductor Design. Constant Voltage Transformer Design (CVT). Three Phase Transformer Design. Flyback Converter Design. Forward Converter Transformer and Inductor Design. Input Filter Design. Current Transformer Design. Winding Capacitance and Leakage Inductance. Quiet Converter Design. Rotary Transformer Design. Planar Transformers. Derivation for the Design Equations. Index.
1,054 citations
TL;DR: In this paper, the authors present a comprehensive procedure for calculating all contributions to the self-capacitance of high-voltage transformers and provide a detailed analysis of the problem, based on a physical approach.
Abstract: The calculation of a transformer's parasitics, such as its self capacitance, is fundamental for predicting the frequency behavior of the device, reducing this capacitance value and moreover for more advanced aims of capacitance integration and cancellation. This paper presents a comprehensive procedure for calculating all contributions to the self-capacitance of high-voltage transformers and provides a detailed analysis of the problem, based on a physical approach. The advantages of the analytical formulation of the problem rather than a finite element method analysis are discussed. The approach and formulas presented in this paper can also be used for other wound components rather than just step-up transformers. Finally, analytical and experimental results are presented for three different high-voltage transformer architectures.
255 citations
Additional excerpts
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TL;DR: In this article, a lookup table-based digital controller is applied to achieve on-line efficiency optimization by programming switching frequencies and operating modes based on the efficiency optimization processes, which is verified by experimental results on a low cost 65 W flyback dc-dc prototype.
Abstract: This paper presents an approach to efficiency optimization in digitally controlled flyback dc-dc converters over wide ranges of operating conditions. Efficiency is characterized and optimized based on power loss modeling and multivariable nonlinear constrained optimization over power-stage and controller parameters. A valley switching technique is adopted to reduce MOSFET turn-on switching loss in discontinuous conduction mode. An optimization procedure is formulated to minimize power loss weighted over a range of operating points, under a cost constraint. A lookup table-based digital controller is applied to achieve on-line efficiency optimization by programming switching frequencies and operating modes based on the efficiency optimization processes. The proposed on-line efficiency optimization approach is verified by experimental results on a low cost 65 W flyback dc-dc prototype.
109 citations
TL;DR: In this paper, the operational characteristics of a high voltage flyback converter with resonant elements are presented, and a detailed mode analysis and the design procedure are presented in designing the high voltage Flyback converter.
Abstract: This paper presents the operational characteristics of a high voltage flyback converter with resonant elements. In high voltage low power applications, the effect of a transformer’s stray capacitance might be the most important factor that influences the overall performance of the circuit. A detailed mode analysis and the design procedure are presented in designing the high voltage flyback converter. To verify and confirm the validities of the presented analysis and design procedure, a computer simulation and experiments have been performed.
21 citations
13 Nov 2014
TL;DR: In this paper, the authors present a digital control technique to achieve valley switching in a bidirectional flyback converter used to drive a dielectric electro active polymer based incremental actuator.
Abstract: This paper presents a digital control technique to achieve valley switching in a bidirectional flyback converter used to drive a dielectric electro active polymer based incremental actuator. The incremental actuator consists of three electrically isolated, mechanically connected capacitive actuators. The incremental actuator requires three high voltage (~2.5 kV) bidirectional DC-DC converters, to accomplish the incremental motion by charging and discharging the capacitive actuators. The bidirectional flyback converter employs a digital controller to improve efficiency and charge/discharge speed using the valley switching technique during both charge and discharge processes, without the need to sense signals on the output high-voltage side. Experimental results verifying the bidirectional operation of a single high voltage flyback converter are presented, using a film capacitor as the load. Energy efficiency measurements are provided.
11 citations
Additional excerpts
...iLm(t) = Vg Zc sinwrt+ i(t1)coswrt (2)...
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