Study on Non-Thermal Food Processing Utilizing an Underwater Shockwave

Modification of Cockcroft–Walton-Based High-Voltage Multipliers with 220 V and 50 Hz Input for Non-Thermal Food Processing Apparatus

“…The basic requirements for a good high-voltage multiplier (HVM) are high response speed, high voltage efficiency, and small number of components used. For utilizing the conventional Cockcroft-Walton-based HVMs with 100 V and 50 Hz or 100 V and 60 Hz proposed in [10,12,28,29] in the 220 V and 50 Hz power system, this paper presents a technique to modify their circuit realizations to be the new schemes that can apply the 220 V and 50 Hz input to produce the high DC output in the desired range. Table 3 summarizes the realization methods of the three proposed HVMs (HVM-A, HVM-B, and HVM-C).…”

“…The underwater shockwave can be generated by utilizing gap discharge [6,7], wire explosion [8,9], wire discharge of dual electrodes [10], or two pairs of restoration electrodes [11]. A typical non-thermal food processing system using underwater shockwaves consists of a high-voltage generator, big capacitor, high-voltage switch, and pressure vessel [10,12]. Generally, a high-voltage multiplier (HVM) that can produce a high DC voltage such as 3.5 kV from a low AC voltage is utilized as the high-voltage generator.…”

“…The HVM, as well as its discharge technique, is obviously an important component in underwater shockwave generation [10,11]. For example, an HVM that can produce underwater shockwaves at high speed can provide high production capacity for non-thermal food processing [12]. The other basic requirements for good HVMs used in non-thermal food processing are small size, light weight, and high voltage efficiency [14].…”

“…The goal of this paper is to propose a topological modification of three interesting design techniques for realizing bipolar HVMs with 220 V and 50 Hz input to produce the DC output between 3.5 and 4.0 kV, which is suitable to generate underwater shockwaves for non-thermal food processing apparatus. Three proposed HVMs, called HVM-A, HVM-B, and HVM-C, were modified from the CWM-based circuit configurations in [10,12,28,29], respectively. The design of the circuit topology of each HVM for 220 V and 50 Hz input requires considerable modification of the sub-circuits used for performing multiplication or amplification because the input signal requirement is changed.…”

“…This means that the HVM-A provides two amplification stages. Figure 1b shows the circuit realization of the second proposed HVM, referred to as HVM-B, which is based on the design technique introduced in [10,12]. The main parts of the HVM-B are the positive/negative HWRs (or AC-DC rectifier) and the parallel-connected positive/negative CWMs.…”