Cascaded H-bridge multilevel inverter based pulsed power supply for liquid food sterilization

This paper proposes a Cascaded H-bridge Multilevel Inverter (CHMI) based pulsed power supply for the sterilization of liquid foods using Pulsed Electric Field (PEF). The utilization of a CHMI allows the system to reach high voltage without the use of transformers while fulfilling the pulse requirements for effective liquid food sterilization. By using the CHMI topology, no extra clamping diodes or voltage balancing capacitor is needed. In this work, the proposed CHMI circuit operation is simulated using MATLAB/Simulink where unipolar and bipolar square wave pulses with pulse width range of 1 μs to 1 ms are generated. A peak output voltage of 6 kV and peak output power of 3.6 kW have been obtained with both values meeting the pulse specifications for liquid food sterilization applications.