A Novel IC Measurement Without Blanking Time for Short-Circuit Protection of High-Power IPM

Zhaoliang Meng,Lei Wu,Yuan Yang,Yang Wen,Shengsheng Ai,Zhengpeng Fang,Yong Gao

doi:10.1109/access.2020.2984542

Abstract

Intelligent power module (IPM) short-circuit protection is a key factor in improving the reliability of power electronics systems. The conventional short-circuit detection method based on monitoring the collector-emitter voltage (VCE) desaturation has a blanking time and is slow to respond to any type of shortcircuits. Furthermore, the diC/dt method cannot be used in the IPM due to the absence of Kelvin emitter. A slow short-circuit protection process can have an irrecoverable and destructive impact on the reliability of the IPM. In this paper, a new high-power IPM topology with an internally integrated shunt is designed to realize real-time current detection, which can achieve fast short-circuit detection without any blanking time. A prototype 1700 V/150 A IPM is manufactured, and a corresponding fast short-circuit protection circuit is designed. Experimental results show the effectiveness of the integrated shunt method as its performance is significantly better than that of the VCE desaturation method. The proposed IPM needs 380 ns and 1.4 μs to detect short-circuits of types I and II, respectively. The short-circuit withstand times for short-circuits of types I and II are 2.06 μs and 0.62 μs, respectively. In addition, the short-circuit energy losses for shortcircuits of types I and II are reduced by 66% and 64.3%, respectively, compared to the VCE desaturation method. The proposed method can also be used as a reference for other IPM designs.

Highlights

An intelligent power module (IPM) is a compact and selfregulating module that encapsulates the IGBT chips, diode chips and various driver and protection circuits within the same insulation unit
It can be observed from the simulation results that the temperature of the shunt resistor is 20◦C lower than that of the IGBT and diode chips, which is consistent with the direct bond copper (DBC) backplane temperature
The lower IGBT serves as the device under test and an air-core inductor L1 serves as the inductive load

Summary

INTRODUCTION

An intelligent power module (IPM) is a compact and selfregulating module that encapsulates the IGBT chips, diode chips and various driver and protection circuits within the same insulation unit. Due to the shortcomings of the existing methods, in this paper a low-cost fast current measurement IPM design without blanking time is proposed. The current value IC can be obtained without any blanking time by measuring the voltage across both ends of the shunt resistors This measurement method is simple, fast, highly accurate and reliable. When a short-circuit occurs, the high-power IPM must be turned off quickly within the withstand time to avoid any damage, while ensuring that the short-circuit current and voltage during turn-off transition are limited to the short-circuit safe operating area (SCSOA) of the IPM module. The detection points A and B can facilitate fast and direct short-circuit protection of the module by leading to the direction of the IGBT emitter current. The shunt resistors can effectively reflect the change in IC, irrespective of normal commutation, bridge arm short-circuit, load short-circuit or phase to the ground short-circuit

DETECTION PRINCIPLE AND RELIABILITY ANALYSIS

FAST DETECTION AND PROTECTION CIRCUITS

EXPERIMENTAL RESULTS

CONCLUSION