Series resonant ZCS-PFM DC-DC converter with multistage rectified voltage multiplier and dual-mode PFM control scheme for medical-use high-voltage X-ray power generator
01 Nov 2000-Vol. 147, Iss: 6, pp 527-534
TL;DR: In this paper, a series resonant high frequency transformer-linked multistage DC voltage multiplier was proposed for X-ray power generator applications, where the secondary turn numbers and secondary-side stray capacitance of the high-voltage, high-frequency transformer, as well as the rectifier diode voltage ratings were reduced.
Abstract: In general, high-voltage DC power supplies employing a variety of high-frequency inverters are implemented for constant value control schemes. In particular, their good transient and steady state performances cannot be achieved under wide load variations for a medical-use high-voltage X-ray generator, ranging from 20 kV to 150 kV in the output voltage and from 0.5 mA to 1250 mA, respectively. A high-voltage DC power supply designed for X-ray power generator applications is considered, which uses a series resonant inverter-linked multistage DC voltage multiplier instead of a conventional high-voltage diode module rectifier connected to the secondary side of a high-voltage transformer. A constant on-time/variable frequency control scheme of this converter operating at zero-current soft switching mode is described. Introducing the capacitor-diode cascaded multistage voltage multiplier, the secondary turn numbers and secondary-side stray capacitance of the high-voltage, high-frequency transformer, as well as the rectifier diode voltage ratings, can be greatly reduced. It is shown that the proposed converter control scheme of the two-step selective changed frequency selection switching is more effective for improving the output voltage responses. The series resonant high frequency transformer-linked voltage-multiplying rectifier is evaluated for an X-ray high-voltage generator on the basis of simulation analysis and observed data in experiment.
Citations
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TL;DR: In this paper, the authors comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques, and discuss the advantages and disadvantages of these voltage boosting techniques and associated converters.
Abstract: DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.
1,230 citations
TL;DR: In this article, a comparative analysis has been presented on various topologies of isolated and non-isolated DC-DC converters, based on the conventional basic boost converter, for photovoltaic (PV) systems.
110 citations
TL;DR: It is shown that, under the derived design conditions, LC-LC RC also exhibits constant output current and in-phase source voltage and current, simultaneously at all loading conditions, resulting in improved output characteristics.
Abstract: The transformer winding capacitance, which is significant in high-voltage power supplies, is not gainfully utilized in an LCL-T resonant converter (RC). A simplified analysis presented in this paper predicts the severe degradation of output current regulation of an LCL-T RC due to transformer winding capacitance. The presence of winding capacitance, in fact, changes the third-order LCL-T resonant tank into fourth-order LC-LC topology. Using an AC analysis, it is shown that, under the derived design conditions, LC-LC RC also exhibits constant output current and in-phase source voltage and current, simultaneously at all loading conditions. Thus, the transformer leakage inductance and winding capacitance are gainfully utilized as a part of a resonant network, resulting in improved output characteristics. Closed-form expressions for the converter gain and component stresses are derived. The condition for converter design optimized for the minimum size of the resonant network is obtained. Experimental results on a prototype 100-mA 2-kV DC power supply confirm the observations of analysis.
78 citations
TL;DR: It is shown that the range of zero-voltage-switching operation would extend significantly since the variations of the phase shift can be reduced by this topology, and high efficiency is achievable for a wide range of operation.
Abstract: This paper presents the steady-state analysis of a fixed-frequency phase-shift LCLC resonant converter with a capacitive output filter which is a very attractive topology for high-voltage applications. A conventional modeling procedure cannot thoroughly describe the converter behavior particularly at the load side. A comprehensive converter analysis is presented, and the obtained analytical expressions precisely describe the converter behavior. This paper shows that the range of zero-voltage-switching operation would extend significantly since the variations of the phase shift can be reduced by this topology. Therefore, high efficiency is achievable for a wide range of operation. This paper also provides some converter practical description for high-voltage implementation. The experimental results obtained from a 1.8-kW prototype verify the theoretical analysis and demonstrate the validity and accuracy of the employed model.
64 citations
TL;DR: In this paper, a dual-mode input voltage modulation (IVM) control scheme for a three-phase zero current switching series resonant (SR) inverter-fed three phase voltage-multiplier based X-ray power supply is proposed to achieve a quick rise of output voltage.
Abstract: A dual-mode input voltage modulation (IVM) control scheme for a three-phase zero current switching series resonant (SR) inverter-fed three-phase voltage-multiplier based X-ray power supply is proposed to achieve a quick rise of output voltage. In this control scheme, a quasi-resonant control circuit is connected at the lower arm of the three-phase inverter to control the effective input voltage across the inverter by raising or lowering the voltage level at the lower arm of the inverter. At the startup of the power supply, the quasi-resonant control circuit shorts the lower arm of the three-phase SR inverter to ground, causing the inverter to see maximum voltage and the output voltage to rise with maximum speed toward the target voltage. As the output voltage reaches 90% of the target voltage, the effective input voltage across the inverter is reduced to a value that corresponds to the target output voltage by raising the voltage level at the lower arm of the inverter. As a result, the rise rate of the output voltage slows down and overshoot is prevented. Experimental results based on the scaled-down laboratory prototype are presented to verify the effectiveness of the proposed dual-mode IVM control scheme.
60 citations
References
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Book•
26 Jul 1989
TL;DR: In this paper, the authors present a simulation of power switch-mode converters for zero-voltage and/or zero-current switchings in power electronic converters and systems.
Abstract: Partial table of contents: Overview of Power Semiconductor Switches Computer Simulation of Power Electronic Converters and Systems GENERIC POWER ELECTRONIC CIRCUITS dc--dc Switch-Mode Converters Resonant Converters: Zero-Voltage and/or Zero-Current Switchings POWER SUPPLY APPLICATIONS Power Conditioners and Uninterruptible Power Supplies MOTOR DRIVE APPLICATIONS dc Motor Drives Induction Motor Drives Synchronous Motor Drives OTHER APPLICATIONS Residential and Industrial Applications Optimizing the Utility Interface with Power Electronic Systems SEMICONDUCTOR DEVICES Basic Semiconductor Physics Power Diodes Power MOSFETs Thyristors Emerging Devices and Circuits PRACTICAL CONVERTER DESIGN CONSIDERATIONS Snubber Circuits Gate and Base Drive Circuits Design of Magnetic Components Index
5,911 citations
11 Mar 1990
TL;DR: In this article, a steady-state analysis is presented with complete characterization of the converter operation and the design procedures based on the analysis are presented and the various losses in the circuit assessed.
Abstract: A steady-state analysis is presented with complete characterization of the converter operation. A small-signal model of the converter is established. The design procedures based on the analysis are presented and the various losses in the circuit assessed. Critical design considerations for a high-power, high-voltage application are analyzed. The results of the analysis are verified using a high-voltage. 2 kW prototype. >
875 citations
TL;DR: In this paper, the series and parallel resonant topologies, as well as a newly discovered hybrid resonance topology are compared for high-voltage applications and it is found that the parallel topology leads to the lowest peak switch current and the most ideal behavior.
Abstract: Because of their tolerance of transformer nonidealities, resonant converters are considered to be well-suited to high-voltage applications. The series and parallel resonant topologies, as well as a newly discovered hybrid resonant topology are compared for high-voltage applications. Design criteria which incorporate transformer nonidealities are developed and used in the construction of high voltage prototypes for each topology. It is found that the parallel topology leads to the lowest peak switch current and the most ideal behavior. >
179 citations
TL;DR: In this paper, an expression for the equivalent source resistance of the capacitor diode voltage multiplier circuit is derived, and the distribution of capacitors that minimizes source resistance is presented.
Abstract: An expression for the equivalent source resistance of the capacitor diode voltage multiplier circuit is derived. The source resistance is found to increase as the cube of the multiplication factor, explaining the poor regulation observed with large multiplication. The distribution of capacitors that minimizes source resistance is presented. Good regulation is shown to be necessary for high efficiency, and to require relatively larger capacitors than needed for ripple filtering.
144 citations