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Subject: search.filters.subject.Non-thermal food processing

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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
    ;
    Eguchi, Kei
    ;
    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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    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
    ;
    Eguchi, Kei
    ;
    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.
      1
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    Switched capacitor-based high voltage multiplier with 220v@50hz input for generating underwater shockwaves
    (2020-01-01)
    Jaiwanglok, Anurak
    ;
    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.
      4
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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 high-voltage multiplier combined with Cockcroft-Walton voltage multipliers and switched-capacitor AC-AC converters
    (2017-06-01)
    Eguchi, Kei
    ;
    Wongjan, Anan
    ;
    Julsereewong, Amphawan
    ;
    Do, Wanglok
    ;
    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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    Parallel-connected high voltage multiplier with symmetrical structure
    (2014-01-01)
    Eguchi, Kei
    ;
    Pongswatd, Sawai
    ;
    Terada, Shinya
    ;
    Oota, Ichirou
    A high voltage multiplier is proposed for non-thermal food processing systems utilizing an underwater shockwave. Unlike conventional Cockcroft-Walton Voltage Multiplier (CWVM) providing a DC output from an AC input, the proposed multiplier consists of two switched-capacitorbased DC-DC converters with different polarities. Owing to the symmetrical bipolar structure without magnetic component, the proposed multiplier can achieve faster response speed and lower voltage drop than the conventional CWVM. The theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulations show the effectiveness of the proposed voltage multiplier. © (2014) Trans Tech Publications, Switzerland.
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