An Improved Protection Circuit Design for Fast Detection of Short-Circuit in IPM

Abstract

Short-circuit protection plays a vital role in ensuring the overall reliability of intelligent power module (IPM), where the shorter the duration of a short-circuit fault, the smaller its impact on the module. The conventional $V_{\mathrm {CE}}$ desaturation detection circuit suffers from a blanking time problem. This paper aims to solve this problem by improving the IPM short-circuit fast detection and protection circuit with integrated shunts in order to achieve ultra-fast detection and protection of the IPM short-circuit faults. At the same time, the number of shunts is decreased from three to two, which reduces the impact on the power density of the device. First, the types of IPM short-circuit faults and the experimental principle of a short-circuit are introduced in this paper. Second, the overcurrent fault protection of the improved circuit with the shunts integrated at different positions in the IPM power unit is analyzed and verified using the PSPICE simulations. Third, a method for selecting the component parameters of a compensation link of the improved circuit is proposed, and the functions for the remaining parts in the circuit are introduced. Last, it is verified through experiments that the improved circuit can quickly detect various short-circuit faults, and initiate the corresponding shutting down of the insulated gate bipolar transistor (IGBT) after 490 ns. Compared with the conventional $V_{\mathrm {CE}}$ desaturation detection method, the detection time of the proposed method and the associated short-circuit loss for modules under different short-circuit faults are significantly reduced.

Keywords

• Insulated gate bipolar transistor (IGBT)
• intelligent power module (IPM)
• short-circuit detection and protection
• shunts