Evaluation Model of Loop Stray Parameters for Energy Storage Converter of Hybrid Electric Locomotive

Abstract

When the silicon carbide (SiC) power module is applied to the energy storage converter of a hybrid locomotive, under the action of di/dt and loop stray inductance, it is easy to produce excessively high voltage overshoot, which affects the battery life and stimulates high-frequency oscillations, causing power devices to withstand greater electrical stress. In order to optimize the system layout and improve system performance, it is extremely necessary to accurately extract and evaluate the loop inductance. This paper takes the typical high-frequency converter structure as the object, establishes an equivalent model of the circuit, and quantitatively analyzes the loop inductance from a mathematical point of view. For the circuit after the parallel of absorption capacitor, the small signal model is used to analyze and reveal the role and influence of the absorption capacitor. Finally, the calculation results of the model are compared through a double-pulse experiment. The results show that the error between the model and the experimental results is about 1%, and the effect of evaluating the stray parameters of the converter circuit is good, and it can provide a theoretical support for the selection and design of the absorption capacitor.

Keywords

• SiC module
• commutation circuit
• stray inductance
• extraction and evaluation