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Journal of Science Engineering Technology and Management Science
Volume 02, Issue 05, May 2025 ISSN: 3049-0952
www.jsetms.com DOI:10.63590/jsetms.2025.v02.i05.pp20-25
Published by: Surya Publishers www.jsetms.com
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An LC Filter and IGBT-Based High Regulated Low Ripple DC
Power Supply
Wang Chie
Department of Energy and Power Engineering, Tsinghua University, China
Corresponding Author: wangcheitpower@gmail.com
To Cite this Article
Wang Chie, “An LC Filter and IGBT-Based High Regulated Low Ripple DC Power Supply”, Journal of Science
Engineering Technology and Management Science, Vol.
02,
Issue 05, May 2025,
pp:20-25,
DOI: http://doi.org/10.63590/jsetms.2025.v02.i05.pp20-25
Submitted: 12-02-2025 Accepted: 28-04-2025 Published: 04-05-2025
_____________________________________________________________________________________________
Abstract: Transmission of stable ripple-free power to heating regions is necessary to maintain temperature stability.
Ripples in the power supply would result in high power losses together with unpredictable and abnormal temperature
rises and power state instability. Excessive current ripple causes electrolytic capacitors in the circuit to decrease their
operational life span. This article presents a plan that reduces load management ripple factor to 0.4% by using simple
cost-effective available electronic components.
Keywords: Operational amplifier, LC filter, IGBT, and ripple factor
This is an open access article under the creative commons license https://creativecommons.org/licenses/by-nc-nd/4.0/
_____________________________________________________________________________________
I. Introduction
The advancement of constant current voltage power source technology has resulted from two major
developments including expensive high-speed control processors and fast-switching insulated-gate bipolar transistor
(IGBT) technology. A growing requirement exists for an advanced power supply system which provides strict control
together with low ripple characteristics and strong current capability to heat high-temperature filaments. The designing
of filament power supplies has proven challenging because it requires consideration of non-ideal device characteristics
alongside power source disturbances and load changes.
The development of advanced high-energy physics and novel particle accelerator applications within
industries and healthcare demands improved regulatory power sources for filament systems. The research introduces
a new method for developing a high current constant dc power supply. The system uses analogue electronics
components for control operations. We utilize the IGBT capability to change current passage during linear operation
through gate to emitter voltage adjustments.
II. Research Method
The controller circuit detects output voltage changes by providing enough gate-to-emitter voltage to modify the current
flow and thus transform the load voltage. The procedure continues unless the load voltage achieves its target value.
The load voltage remains mostly stable even though there are slight variations because these fluctuations become
insignificant compared to the main load voltage. Hence the ripple factor stays low. Any sudden load alterations within
the circuit produce minimal effect on the fixed output voltage due to minimal regulation. The schematic diagram of
the proposed power supply for filaments is shown above. Diode converter combined with L-type LC filter, potential
divider, IGBT, bleeder resistance, non-inverting buffer, inverter, differential amplifier, and REF01 form the circuit. A
180VA, 230V/18V transformer serves as the experimental unit to generate 10V at 10A output. Design parameters
include 8V extra voltage to compensate the voltage drop that occurs in the rectifier and IGBT circuit. The transformer
produces AC power at its outlet which becomes DC voltage using full wave rectifier bridge devices. A L type LC
filter reduces the harmonics which appear in the rectifier output waveform.
A bleeder resistance helps the filter capacitor to drain energy when power supply interruption occurs. The
output voltage stability function of the project relies on the G4PH50UD IGBT. The circuit joins the load to two 10k
resistors as series combinations with feedback voltage taken from the middle point. Loading effects on the voltage
An LC Filter and IGBT-Based High Regulated Low Ripple DC Power Supply
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controller circuit are blocked by the added buffer element. The feedback voltage acquires a negative polarity against
the load circuit ground because measurements occur from the high potential load reference point.
Fig 1: Principle and circuit topology
A gate voltage VGE above threshold voltage Vth operates as a device turn-on mechanism. The gate voltage elevates
to create an inversion layer which links the drain sections to the source areas through a channel. During operation the
source adds electrons to the drift area and at the same time junction J3 emits holes into the n-doped drift region.
Injecting electrons and holes into the drift area changes its conductivity to higher levels because the electron and hole
concentrations exceed initial n-doping values. The IGBT achieves low on-state voltage because its resistance
decreases when the conductivity modulation takes effect.
Fig 2: L Type LC filter
An LC Filter and IGBT-Based High Regulated Low Ripple DC Power Supply
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Fig 3: Output of L type LC filter
Some holes generated by injection in the drift zone will combine with each other while others will spread
across the area to the p-type interface where they will become trapped. Through its MOSFET current the IGBT
operates as a wide-base p-n-p transistor that allows channel current to serve as base driving current. A device requires
rise time to advance from 10% to 90% of its base value. We can determine and estimate rise time theoretically by
implementing a step input on the ref. The theoretical calculation of the increase time should match closely with the
actual measured value.
Fig 4: The variation of output voltage across the load
We can abruptly turn the ref input on to its highest value by using a switch at the input. The output of this
operation is the system's step response, which can be thought of as a step change in input. The plot provides us with
the system's step reaction. The output is CH1 (yellow), whereas the reference input is CH3 (purple).
An LC Filter and IGBT-Based High Regulated Low Ripple DC Power Supply
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Fig 5: Rise time
The input and output are separated by a considerable amount of delay. This loop delay is brought on by all
types of capacitances in the circuit, both real and stray. This delay can be decreased by employing more linear circuit
components and proper wiring. In this case, the load is connected across Channel 1. A rising time of 608 µs was
recorded by the oscilloscope. Our computed value, 341.542 µs, was sufficiently near the practical value.
Fig 6: Response time at no load
An LC Filter and IGBT-Based High Regulated Low Ripple DC Power Supply
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Fig 7: Response time at full load
The output waveform is represented by CH3 (yellow), and the input reference voltage waveform is
represented by CH1 (purple). The reference input's full value is used to compute the ripple.
Fig 8: Ripple Factor at full load
The system output voltage shows a downward trend with the increase of load value from zero to maximum.
Capsule depletion rate becomes reduced because the IGBT experiences decreased current when operating without a
load. Switching the load abruptly will reduce the capacitor voltage because the circuit acquires immediate uniform
current flow. The drop in load voltage causes an accompanying change to the feedback voltage measurement. The
voltage regulator conducts procedures to restore the load voltage to its original value. The device performs the reverse
action when a system moves from full load operation to no load conditions.
III. Conclusion
To match the impedance in the feedback path, the differential op-amp's non-inverting terminal is connected
to a 0.3 µF capacitor and 2.5MΩ resistors. The differential amplifier's subtractive feature allows for higher noise
suppression from the output when both input terminals have the same impedance. Because of the controller circuit's
quick controlling action, it is also evident that the ripple factor from the theoretical calculation has significantly
decreased. In order to guarantee quick dynamic reaction, the rise time is likewise relatively short. Additionally, it has
been found that raising the differential stage's gain to an ideal level actually makes the input-output response more
linear because the IGBT's base signal is likewise amplified.
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References
[1] Allen Mottershead, Electronic Devices and Circuits: An Introduction, Goodyear Publishing Company, 1973.
[2] Chattopadhyay D., Rakshit P. C., Electronics Fundamentals And Applications, New Age International, 2008.
[3] Wellenstein, H. F, Ensman, R. E. “A Regulated Filament Temperature Power Supply for Electron Guns” , Review of Scientific Instruments,
Jul 1973, Volume: 44 , Issue: 7, pages 922- 923.
[4] Suxuan Guo, Dichen Liu, “Analysis and design of output LC filter system for dynamic voltage restorer”, Proceedings to the Twenty-Sixth
Annual IEEE Applied Power Electronics Conference and Exposition (APEC), 6-11 March 2011, Page(s): 1599- 1605.
[5] Beiranvand, R. Rashidian B., Zolghadri M.R. Alavi, S.M.H., “Designing an Adjustable Wide Range Regulated Current Source”, IEEE
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