Julsereewong, Amphawan

Preferred name

Alternative Name

Julsereewong, A.

Main Affiliation

School of Engineering

amphawan.ju@kmitl.ac.th

Now showing 1 - 10 of 13

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Modification of Cockcroft-Walton-based high-voltage multipliers with 220 V and 50 Hz input for non-thermal food processing apparatus
(2020-08-01)
Jaiwanglok, Anurak
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Eguchi, Kei
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Smerpitak, Krit
;
Julsereewong, Amphawan
A design of high-voltage multipliers to generate underwater shockwaves is one of the most important factors for successfully providing non-thermal food processing in a cost-effective manner. To be capable of fully utilizing the Cockcroft-Walton-based high-voltage multipliers for underwater shockwave generation, this paper presents a topological modification of three interesting design approaches in bipolar structure for 220 V and 50 Hz AC input to generate more than 3.5 kV DC output within short time periods. In addition to Cockcroft-Walton multipliers (CWMs), the first modified scheme employs a positive full-wave rectifier (FWR) and positive voltage multiplier block (VMB), the second modified scheme employs positive/negative half-wave rectifiers (HWRs), and the last modified scheme employs a switched-capacitor AC-AC converter. To comparatively analyze their performances, the digitally controlled operations of the modified realization schemes as well as their electrical characteristic estimation based on a four-terminal equivalent model are described in detail. The effectiveness of three modified circuit configurations and the correctness of the given theoretical analysis are verified through SPICE (Simulation Program with Integrated Circuit Emphasis) simulation results. The formulas achieved from theoretical estimation are particularly useful when designing the proposed high-voltage multipliers (HVMs) because good agreement between the theoretical and simulation results can be achieved.
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Switched capacitor-based high voltage multiplier with 220v@50hz input for generating underwater shockwaves
(2020-01-01)
Jaiwanglok, Anurak
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Eguchi, Kei
;
Julsereewong, Amphawan
Non-thermal food processing using underwater shockwaves is a cost-effective technology for preserving food items with minimal impacts on their nutritious property. In order to generate underwater shockwaves, a high voltage multiplier is the major element for system hardware implementation. To support the 220V and 50Hz AC input for generating 3.7kV DC output, this paper presents the high voltage multiplier based on switched capacitor technique. The proposed circuit consists of three main components, which are AC-DC rectifier, level shift driver, and parallel-connected voltage multiplier circuit. The theoretical relationship analysis utilizing a 4-terminal equivalent circuit is described for investigation of not only the output voltage but also the energy loss due to internal resistance and the power efficiency of the proposed high voltage multiplier. In addition, the operations of the proposed circuit are also simulated by using PSPICE program to confirm its workability.
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Design of a non-thermal food processing system utilizing wire discharge of dual electrodes in underwater
(2018-06-01)
Eguchi, Kei
;
Jaiwanglok, Anurak
;
Julsereewong, Amphawan
;
Asadi, Farzin
;
Abe, Hiroto
To provide nutritious and fresh processed foods, non-thermal food processing technologies have been developed in recent years. Among others, a non-thermal food processing method utilizing underwater shockwaves has cost-effectiveness. In this method, the design of a high voltage multiplier and its discharging method are key factors for processing target foods effectively. This paper proposes a non-thermal food processing system utilizing wire discharge of dual electrodes in underwater. Unlike conventional non-thermal food processing systems, the proposed system has two pairs of electrodes with thin metal wires. Owing to the electric discharge using thin metal wires, the energy to generate underwater shockwaves can be decreased. For this reason, by only one electric discharge, both sides of the target food are crushed by the proposed technique. The experiments using a laboratory prototype clarified that the proposed method can soften the whole flesh of the target food effectively. Furthermore, by assuming a four-terminal model, an equivalent model of the high voltage multiplier was analyzed theoretically. Concerning the series-connected voltage multiplier, the design conditions were derived to estimate the characteristics such as output voltage and power efficiency.
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Design of a nesting-type switched-capacitor AC/DC converter using voltage equalizers
(2017-01-01)
Eguchi, Kei
;
Junsing, Tipparat
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Julsereewong, Amphawan
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Do, Wanglok
;
Oota, Ichirou
For electric appliances, an electric circuit that changes an alternating current (ac) into a direct current (dc) is necessary. Among others, a small and light ac/dc converter is indispensable to develop novel mobile devices. As one of the most promising design approaches, the ac/dc converter designed by switched-capacitor (SC) techniques attracts many researchers’ attention, because the SC ac/dc converter can be implemented without a high turn ratio transformer. Owing to the heavy transformer-less design, the SC ac/dc converter can realize smaller size and lighter weight than traditional ac/dc con-verters. However, the SC ac/dc converter suffers from complexity of the circuit control and the inflexibility of conversion ratio. To overcome these problems, this paper proposes a nesting-type SC ac/dc converter using voltage equalizers. Unlike conventional SC ac/dc converters, the proposed converter consists of a full waveform rectifier with a big capaci-tor and nested voltage equalizers. In the nested voltage equalizers, a part of the capacitor voltage of a voltage equalizer is converted by other voltage equalizers, where each voltage equalizer is controlled by non-overlapped two-phase clock pulses. By the nesting conver-sion, the conversion ratio of the proposed converter is expressed as a reverse value of the total sum of main capacitors’ voltage ratios. Therefore, the proposed converter can achieve not only simple circuit control but also flexible conversion ratios. Concerning the 1/9× step-down SC ac/dc converter, the advantages of the proposed converter were investigated by theoretical analysis, simulated program with integrated circuit emphasis (SPICE) simulations, and experiments. First, mathematical formulas for estimating the characteristics of the proposed converter were derived theoretically by utilizing a simple four equivalent circuit. Then, by comparing the proposed converter with conventional SC ac/dc converters, the effectiveness of the proposed converter was clarified by SPICE simulations. Finally, the feasibility of the proposed converter was confirmed by using the experimental circuit implemented on a breadboard.
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Design of a high-voltage multiplier combined with Cockcroft-Walton voltage multipliers and switched-capacitor AC-AC converters
(2017-06-01)
Eguchi, Kei
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Wongjan, Anan
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Julsereewong, Amphawan
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Do, Wanglok
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Oota, Ichirou
In recent years, the non-thermal food processing is receiving much attention, because the non-thermal food processing can offer nutritious and fresh processed foods at low cost. In the non-thermal food processing, an underwater shockwave is utilized by discharging a high voltage in water. To generate the underwater shockwave, this paper proposes a novel high voltage multiplier designed by connecting a bipolar Cockcroft- Walton voltage multiplier (CWVM) with a switched-capacitor (SC) direct ac-ac converter in series. In the proposed multiplier, first, an ac input is amplified to double by the inductor-less ac-ac converter. Then, the output of the ac-ac converter is stepped-up again by the bipolar CWVM. Therefore, owing to the inductor-less series-connected bipolar topology, the proposed multiplier can achieve smaller size and higher gain than existing multipliers. Concerning the proposed multiplier with 26 × step-up gain, the operation principle and theoretical analysis are discussed in detail. Furthermore, the feasibility and effectiveness of the proposed multiplier are demonstrated by simulation program with integrated circuit emphasis (SPICE) simulations.
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Alternative of high voltage multipliers utilizing Cockcroft–Walton multiplier blocks for 220 V and 50 Hz input
(2020-12-01)
Jaiwanglok, Anurak
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Eguchi, Kei
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Julsereewong, Amphawan
;
Pannil, Pittaya
In order to be practical for converting 220 V and 50 Hz AC input into high DC output ranged between 3.5 and 4.0 kV to create underwater shockwaves in non-thermal technique for processing foods, this article presents an alternative approach for modifying conventional high voltage multipliers without magnetic elements, which are based on the use of parallel-connected Cockcroft–Walton multiplier blocks (CWMBs) in bipolar structure. The basic three-stage CWMB scheme as well as the effect of different capacitor values on its output is described. The modified high voltage multiplier with improved response speed consists of a full-wave rectifier (FWR), a two-phase driver block, a parallel-connected positive CWMB, and a parallel-connected negative CWMB. Both output voltage and power efficiency of the proposed scheme can be demonstrated by theoretical analysis results. Moreover, simulation results showing the characteristics of the proposed high voltage multiplier are also included.
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Family of Fibonacci-Type Marx Generators with a Single Inductor in a Three-Phase Configuration
(2024-01-01)
Eguchi, Kei
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Ishibashi, Takaaki
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Julsereewong, Amphawan
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Thepmanee, Teerawat
High-voltage discharge applications have seen a widespread adoption of solid-state Marx generators (SSMGs) in recent years. In this paper, we propose a new hybrid solid-state Marx generator (HSSMG) with a single inductor. Through the application of a three-phase Fibonacci scheme, the HSSMG is capable of achieving a substantial increase in voltage output. Furthermore, the proposed HSSMG is able to generate high voltage efficiently with fewer components. The integration of the Fibonacci and boost modules is a crucial idea in the proposed technique, where the boost module increases the output voltage of the Fibonacci module to achieve higher output voltage. Regarding the proposed two-stage HSSMG, the theoretical feasibility of the proposed topology is confirmed by theoretical analysis and Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. As a result of comparative analysis, it was found that the number of circuit components of the proposed two-stage HSSMG is approximately half that of the traditional SSMG. Moreover, the newly suggested two-stage HSSMG accomplishes more than 86% power efficiency at 5 W.
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Design of a dual-input buck-boost converter for mobile back-lighting applications
(2012-04-01)
Eguchi, Kei
;
Pongswatd, Sawai
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Julsereewong, Amphawan
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Oota, Ichirou
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Terada, Shinya
For mobile back-lighting applications, a dual-input white LED (WLED) driver using a bi-direction buck-boost converter is proposed in this paper. The proposed driver has two input terminals: battery input V <inf>in1</inf> and solar-cell input V <inf>in2</inf>. Unlike conventional drivers using boost converters, step-up SC DC-DC converters, and so on, the proposed converter drives the anode and the cathode of LEDs by using the solar-cell's voltage and the negative stepped-down voltage, respectively. Furthermore, by converting solar energy, the proposed driver can charge a rechargeable battery when the LED backlight is standby mode. Therefore, the proposed driver can achieve long battery lifetime. The validity of the proposed driver is confirmed by SPICE simulations and experiments. SPICE simulations show that the proposed driver can offer the sufficient voltage to drive LEDs by using solar energy and battery energy in spite of the variation in V <inf>in2</inf>. Furthermore, by employing a bi-direction buck-boost converter, the proposed driver provides us to realize long battery lifetime, because the battery charge process was confirmed by experiments. © 2012 ICIC International.
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A dickson-type adder/subtractor dc-dc converter realizing step-up/step-down conversion
(2013-01-16)
Eguchi, Kei
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Julsereewong, Prasit
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Julsereewong, Amphawan
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Fujimoto, Kuniaki
;
Sasaki, Hirofumi
In this paper, a Dickson-type adder/subtractor DC-DC converter realizing step-up/step-down conversion is proposed. Although the conventional Dickson converter cannot achieve step-up/step-down conversion, the proposed converter can provide not only the stepped-up voltage but also the stepped-down voltage by combining the battery energy and the clean energy. Moreover, the proposed converter can achieve many con-version ratios by utilizing hybrid inputs. Therefore, by choosing the optimal combination of conversion ratio, the proposed converter can alleviate the energy loss caused by the output regulation. To evaluate circuit properties, theoretical analyses, simulations and experiments were performed concerning a simple example of the proposed converter. Cir-cuit simulations and experiments showed the following results: (1) The circuit design is appropriate, because the step-up/step-down conversion was confirmed by the experimen-tal circuit. (2) The number of conversion ratios of the proposed converter is three times as large as that of the conventional three-stage ring-type converter. (3) The proposed converter can reduce more than 25% hardware cost than the conventional converter. (4) The derived theoretical formulas are useful to estimate the characteristics of the proposed converter, because the theoretical result corresponded well with the simulated result. © 2013 ICIC International.
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Synthesis and analysis of a dual-input parallel DC-DC converter designed by using switched capacitor techniques
(2011-04-01)
Eguchi, Kei
;
Oota, Ichirou
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Pongswatd, Sawai
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Julsereewong, Amphawan
;
Tirasesth, Kitti
As a building block of mobile equipments, single-input switched-capacitor (SC) power converters have been used. However, the single-input converter is difficult to improve battery runtime by adjusting a voltage conversion ratio, because the ratio of the voltage conversion is predetermined by circuit structure. To solve this problem, a dual-input parallel-connected converter designed by the SC technique is proposed in this paper. Although the conventional single-input converter uses a lithium battery as an input energy source, the proposed dual-input converter uses not only a lithium battery but also solar cells. For the conventional SC converters, the energy conversion of clean energy is difficult, because the voltage of clean energy sources such as solar cells is sensitive to weather condition. To adopt the change in the voltage of clean energy input, the proposed converter provides the multi-state step-up conversion. By converting clean energy, the proposed converter realizes long battery runtime. Moreover, to design the multiple-input converter, the theoretical analysis to clarify circuit characteristics is required, because detailed analyses concerning multiple-input SC DC-DC converters have not been performed yet. Therefore, concerning circuit characteristics of the proposed dual-input converter, handy theoretical formulas are given in this paper. Through SPICE simulations, theoretical analyses and experiments, the validity of the proposed converter is confirmed. The theoretical results correspond well with SPICE simulation results. Therefore, the proposed analysis technique can be extended to the circuit design of other multiple-input SC DC-DC converters. Furthermore, the experimental results show that the proposed converter can generate the stepped-up voltage in spite of the change in the voltage of solar cells. Therefore, the proposed converter can realize long battery runtime. ICIC International © 2011.

Julsereewong, Amphawan

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