Active-short-circuit and locked-rotor modes are common abnormal operations in new energy vehicles. The IGBT junction temperature measurement for these two operating conditions is a challenging problem due to the unexpected large current and the asymmetric operation of semiconductor chips. In addition, different cooling flow rates have a significant influence on the heat dissipation, which will also have an impact on the building of the thermal model. Based on these difficulties, a modified Foster thermal network under active-short-circuit and locked-rotor modes has been presented considering different cooling conditions. The power loss models of the semiconductor chip under abnormal conditions are developed and a modified Foster thermal network based on the NTC temperature sensor is proposed. The model can be adapted to different cooling conditions since the thermal impedance fluctuates slightly at different cooling flow rates. The proposed thermal model is verified with inverter application under active-short-circuit and locked-rotor modes and the experimental performance shows good accuracy compared with the infrared camera measurement results. INDEX TERMS Insulated gate bipolar transistors(IGBTs);active short circuit(ASC) mode; locked-rotor mode; thermal models.
<div class="section abstract"><div class="htmlview paragraph">DC link active discharge is mandatory in new energy vehicles. This paper first analyzes the necessity of active discharge in automotive inverters and then introduces the commonly used discharge methods. After reviewing the pros and cons of the current methods, a new discharge solution using IGBT (Insulated Gate Bipolar Transistor) modules WSC (Weak Short Circuit) is proposed. The essence of WSC is to make one of the shooting through IGBTs (two IGBTS forms a half bridge topology) entering into active work area by controlling its gate voltage V<sub>GE</sub>, where the short current is controlled in safe range and IGBT V<sub>CE</sub> voltage is relative large. Hence, large transient power is produced inside IGBT in this condition. By this method, the DC link capacitor energy will be consumed by the weak turned on IGBT gradually. Since the IGBT module has a dedicated cooling loop, the heat generated during discharging process can be transferred into coolant. In order to discharge the DC link capacitor safely, an optimized discharge topology is suggested in which PWM method is applied. This paper focuses on the intensive evaluation of the IGBT both steady and transient electro-thermal stress under this new discharge method. The simulation and experimental results show that this method can not only discharge the DC link capacitor fast, but also has no risk of IGBT damaging since the IGBT electric and thermal stresses are in the safe operation range during the discharge time. It is proved that this new discharging solution saves cost and is also practical for engineering.</div></div>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.