Transformer parasitic high-frequency inverter-fed DC-DC converter for medical-use X-ray power generator and its digital control

Sun, Junming; Takano, Hiroshi; Nakaoka, M.; Lin, D.

doi:10.1109/icit.1996.601617

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…It should be noted that in practice, R L as determined by the vi characteristic must be adjusted over a wide range depending on the conditions of medical imaging. [1,6,7] There are two methods of control for output voltage regulation of a transformer resonant phase-shift PWM high-frequency inverter-type DCDC converter, namely, PWM control and PFM control. When the phase-controlled rectifier converter and the active PFC converter are connected to the converter input of the system, PAM control is also included.…”

Section: X-ray Tube Characteristics [12]mentioning

confidence: 99%

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A transformer resonant phase‐shifted PWM DC–DC converter for X‐ray power generator and its fuzzy logic‐based learning control scheme

Sun¹,

Takano²,

Nakaoka³

2001

Electrical Engineering Japan

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SUMMARYIn general, medical-use high-voltage X-ray power generators are operated at a variety of required output DC voltages and output current settings for the X-ray tube. A phase-shifted PWM inverter-fed DCDC power converter with a high-voltage transformer parasitic resonant link which is used for an X-ray power generator inherently has stiff nonlinear characteristics due to phase-shifted voltage regulation and diode cutoff operation in a high-voltage rectifier because of the wide load setting ranges in practical applications. However, the superior output voltage response required for a medical-use X-ray power generator could not be sufficiently implemented by various modern linear control approaches because a precise mathematical description with dynamic modeling could not be formulated for wide load variations. For controlling such a nonlinear DCDC power conversion system, a fuzzy reasoning-based learning control technique that duplicates human capabilities and much experience in understanding the dynamic and static behavior of the system are more suitable and effective. This paper presents a phase-shifted PWM full bridge inverter-type high-voltage DCDC power converter with a high-voltage transformer parasitic link and its fuzzy-based learning controller, which has excellent dynamic and static behavior, for use in a medical X-ray power generator operating at a wide variety of load settings. The effectiveness of the feasible fuzzy learning technique used for control of the DCDC power converter is discussed and evaluated based on computer simulations and experimental results in a laboratory setup. It is demonstrated that the feasible fuzzy learning control scheme suitable for this converter is more effective and practical in improving the system output voltage response performance in both transient and steady states for medical-use X-ray power generators. The results of simulations and experiments for this converter are presented in order to illustrate the operating performance of the proposed X-ray power

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Section: X-ray Tube Characteristics [12]mentioning

confidence: 99%

“…Consequently the first-, second-, and third-order types, that is, Eqs. (5), (6), and (7), respectively, are considered with a delay element present, and the results are compared under the learning rules:…”

Section: Learning Of Fuzzy Control Rulementioning

confidence: 99%

A transformer resonant phase‐shifted PWM DC–DC converter for X‐ray power generator and its fuzzy logic‐based learning control scheme

Sun¹,

Takano²,

Nakaoka³

2001

Electrical Engineering Japan

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“…[1,6,7] There are two methods of control for output voltage regulation of a transformer resonant phase-shift PWM high-frequency inverter-type DCDC converter, namely, PWM control and PFM control. In view of the actual use of the medical X-ray tube, it is not necessary to consider a nonlinear characteristic, and the resistance is linearized for the operating point (vi).…”

Section: X-ray Tube Characteristics [12]mentioning

confidence: 99%

Transformer Resonant Phase-Shifted PWM DC-DC Converter for X Ray Power Generator and Its Fuzzy Logic-based Learning Control Scheme

1999

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-In general, medical-use high-voltage X ray power generator works under a variety of operating conditions of the required output DC voltage and the output current setting values for the X ray tube. A phase-shifted PWM inverter-fed DC-DC power converter with a high-voltage transformer parasitic resonant link which is used for an X ray power generator inherently includes its stiff nonlinear characteristics due to phase-shifted voltage regulation and diode cut off operation in a high-voltage rectifier because of the wide load setting regulation ranges in practical applications. However, superior output voltage response performances of a quick rising time in a transient state and low ripple factor in a steady-state which have to be essentially required for a medical-use X ray power generator could not be sufficiently implemented by various linear modern control approaches because a precise mathematical description with dynamic modeling could not be formulated for wide load variations. For controlling such a nonlinear DC-DC power conversion system, a fuzzy-reasoning-based learning control technique to realize the human capability and much experience to understand the system dynamic and static behavior is more suitable and effective. This paper presents a phase-shifted PWM full bridge inverter type high-voltage DC-DC power converter with a highvoltage transformer parasitic resonant link and its fuzzy-based learning controller, which has excellent dynamic and static behaviors to be utilized in a medical-use X ray power generator operating under conditions of a variety of wide load settings. The effectiveness of feasible fuzzy learning control technique of the DC-DC power converter is discussed and evaluated on the basis of the computer simulation and experimental results in a laboratory set-up. It is proved that the feasible fuzzy-based learning control scheme suitable for this converter is more effective and practical to improve the system output voltage response performances in both the transient and steady states for medical-use X ray power generator. The simulated and experimental results of this converter are actually illustrated in order to substantiate the operating performance validity of the inverter type medical-use X ray power generator operated by the feasible fuzzy-based learning control implementation.

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“…High frequency operation enables the whole system to adapt itself more easily to new conditions and parameter changes. In addition, high‐frequency operation of the converters decreases the size and weight of converters and increases their efficiency (Sun et al , 1996). An important drawback of high‐frequency operation is its high switching losses that can be removed by operating the system around the resonance frequency and at lagging power factor mode.…”

Section: Introductionmentioning

confidence: 99%

Steady‐state modeling of a phase‐shift PWM parallel resonant converter

İskender

Üçtug²,

Ertan³

2006

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -To derive an analytical model for a dc-ac-dc parallel resonant converter operating in lagging power factor mode based on the steady-state operation conditions and considering the effects of a high-frequency transformer. Design/methodology/approach -A range of published works relevant to dc-ac-dc converters and their control methods based on pulse-width-modulation technique are evaluated and their limitations in output measurement of higher output voltage converters are indicated. The circuit diagram of the converter is described and the general mathematical model of the system is obtained by deriving and combining the mathematical models of the different converter blocks existing in the system. The derived mathematical model is used to study the steady-state and transient performance of the converter. The deriving procedure of the analytical model for a parallel resonant converter is extensively given and the analytical model obtained is verified by simulation results achieved using MATLAB/SIMULINK and the program written by the authors. Findings -The paper suggests an analytical model for dc-ac-dc parallel resonant converters. The model can be used in the output voltage estimation of a converter in terms of its phase-shift angle and the dc-link voltage.Research limitations/implications -The resources in the library of the authors' university and also the English resources relative to dc-ac-dc converters reachable through the internet were researched. Practical implications -The analytical model suggested can be used in estimating the output voltage of the converters used in high-voltage applications or where there are difficulties in employing sensors in measurement of the output voltage due to high price or implementation problems. Originality/value -The originality of the paper is to present an analytical model for dc-ac-dc parallel resonant converters. Using this model makes it possible to estimate the output voltage of the converter using the dc-link voltage and the phase-shift angle. The proposed model provides researchers to regulate the output voltage of the converters using feed-forward control technique.

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Transformer parasitic high-frequency inverter-fed DC-DC converter for medical-use X-ray power generator and its digital control

Cited by 8 publications

References 2 publications

A transformer resonant phase‐shifted PWM DC–DC converter for X‐ray power generator and its fuzzy logic‐based learning control scheme

A transformer resonant phase‐shifted PWM DC–DC converter for X‐ray power generator and its fuzzy logic‐based learning control scheme

Transformer Resonant Phase-Shifted PWM DC-DC Converter for X Ray Power Generator and Its Fuzzy Logic-based Learning Control Scheme

Steady‐state modeling of a phase‐shift PWM parallel resonant converter

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