Pulsed electric field by Cascaded H-bridge multilevel inverter for liquid food sterilization

This paper focuses on evaluating the effectiveness of a Cascaded H-bridge Multilevel Inverter (CHMI) based pulsed power supply for liquid food sterilization using pulsed electric field (PEF). The utilization of the CHMI allows the system to produce PEF with high stability, less heat and power consumption if compared to the conventional methods such as pulsed forming network (PFN) or transmission line techniques. The CHMI pulsed power supply can attaining high output voltage without using a transformer to meet specification necessities for sterilizing liquid food. By using the CHMI, the power loses due to omission of winding coil can be reduced. A MATLAB/Simulink software has been used to simulate the effectiveness of a 5-level CHMI circuit in order to generate PEF output pulses with pulse width 1 ms and at constant frequency of a 50 Hz. The simulation and experimental results indicate that, an output voltage up to 4.52 kV p-p and maximum output power of 348 W have been generate with the values fulfil the pulse requirements for liquid food sterilization applications. Most importantly, the CHMI has been operated with less power consumption if compared with conventional method that can prove to be beneficial in terms of lowering its cost and size particularly for industrial application to inactivate various type of microbial.