New approach for SCR selection and optimization for Septum magnet power supply with high reliability

TL;DR

This paper introduces a novel method for selecting and optimizing SCRs in septum magnet power supplies, focusing on high reliability and cost-effectiveness by using an I2t derating factor for better component choice.

Contribution

The paper proposes a new selection criterion based on I2t derating factors and validates it through experiments, enhancing SCR reliability in high pulsed current applications.

Findings

SCR selection based on I2t derating factor improves reliability.

Experimental results show the method's effectiveness under thermal stress.

Approach aids in designing low-cost, high-reliability power supplies.

Abstract

A new approach for selection of Silicon-Controlled Rectifier (SCR) for switching high pulsed currents in the septum magnet power supply is described. In this approach, an attempt is made to select the SCR from its I2t rating given in data sheet. For this, a factor which we have called I2t derating factor is defined as the ratio of I2t rating of SCR to the I2t value of current pulse to be switched. Thus, the SCR to be used in power supply is selected from its I2t derating factor. Three different experiments were performed using SCR of different manufacturers, to estimate the value of I2t derating factors. In these experiments, the SCR was subjected to maximum thermal stress till SCR started showing degradation. The forward blocking voltage and the leakage current are the parameters used for characterizing the SCR before and after the stress. The results of these experiments are presented and discussed. This approach will be of great help when pulse rating of SCR, like, transient thermal impedance is not available. Finally, a method is presented which can contribute to design low-cost and high-reliability septum magnet power supply.