System-Based Protection Method for High-Voltage Pulse Generator Switching Units in Biomass Electroporation

Abstract

Background High-voltage pulsed electric field (PEF) technology has emerged as a promising technique for enhancing cell membrane permeabilization for biotechnological and medical applications. Given the parametric instability and low resistivity of biomass when used it as an electrical load, it is imperative for the switching unit to meet specific requirements in terms of load capacity and protection against overloads and short circuits. Methods To construct generators capable of producing high-voltage pulses in the microsecond and millisecond duration ranges, we are incorporating a switching unit that employs a hardware-software method to safeguard critical transistors against overloads and short-circuit currents. Our strategy revolves around utilizing the energy storage capacitor (ESC) both as a means of energy storage and as a current sensor. By monitoring the voltage drop during discharge, we can accurately estimate current parameters. The occurrence of an excessively rapid discharge from the ESC serves as an indicator of a short circuit. The microcontroller calculates ESC discharge limits based on preset parameters within a defined timeframe. Should this limit be exceeded, the system promptly interrupts to address the pulse responsible for the short circuit and halts the further supply of remaining pulses to the load. This sophisticated approach ensures the protection and integrity of the system in the face of potential overloads or short circuits. Results Applying a systemic approach in the design of the presented implementation of protection for key transistors in the switching node from overload and short-circuit current for high-voltage pulse generators (HVPG) in the microsecond and millisecond duration ranges allows for a simpler circuit solution. In this case, the system approach also provides a unified control principle when implementing the considered option for organizing protection, regardless of the number and type of transistors or solid-state switching modules used and connected in parallel. Conclusions The configuration and protective circuitry presented in the article are specifically tailored for shielding switching elements from short-circuit currents, with a primary focus on their application in high-voltage pulse generators (HVPG). These generators are commonly employed in the high-voltage pulse treatment of diverse and unstable loads during the electroporation of biomass. The technical solution expounded in the article is intended for use in the switching nodes of HVPG, particularly those with discharge circuits constructed based on a direct capacitive discharge scheme. Notably, this protection configuration introduces local innovation and is characterized by the circuit's simplicity, achieved through the effective utilization of existing system resources. This protective variant for HVPG switches is particularly well-suited for devices utilized in versatile technological installations with relatively lower performance levels.