On integrity assessment of IGBT-based power stacks used in magnet power supplies for particle accelerators
As a potential improvement of the future power stack designs for lifetime prolongation, this work investigates the possibility for IGBT module’s thermal stressing mitigation using the specialized application as a reference. This investigation is based on LPN simulations. Prior to the LPN modeling, the extensive operation of the magnet power supply in the Negative Temperature Coefficient (NTC) operation region is, experimentally, examined. It is demonstrated that the current and thermal stressing unbalances among the chips inside the Soft Punch Through (SPT) IGBT module operating in the NTC operating region can be neglected and do not have to be considered for the thermal modeling. Moreover, the impact of the material, of the thickness and of the heat convection of the cooling plate on the junction temperature variation and maximum junction temperature is evaluated. It can be stated that, for long current cycles of the specialized application, a relatively thick aluminum cooling plate (3cm) with a moderate heat convection coefficient (10kW/(°Cm2)) may exhibit almost the same performance as a copper cooling plate of equal or even greater thickness (5cm) with a high heat convection coefficient (10kW/(°Cm2)).
Two strategies are proposed with the switching frequency and the gate resistance as parameters for online thermal stressing mitigation. The first strategy reduces the switching frequency in parts of the cycle where a high precision requirement for the output current is not imposed, in order to limit the power losses and the thermal stressing of the IGBT. The second strategy combines the switching frequency reduction in one part of the cycle with the increase of switching frequency and gate resistance in another. By increasing the power losses the junction temperature fluctuation can be limited. Using four typical current profiles from the specialized application, it is shown that both strategies could prolong the IGBTs’ lifetime. It is shown that the contribution of the mitigation strategy to the lifetime prolongation depends on the current profile.
Chalmers, Elektroteknik, Elkraftteknik
On V-ce Method: In Situ Temperature Estimation and Aging Detection of High-Current IGBT Modules Used in Magnet Power Supplies for Particle Accelerators
IEEE Transactions on Industrial Electronics,; Vol. 66(2019)p. 551-560
Artikel i vetenskaplig tidskrift
P. Asimakopoulos, K. Papastergiou, T. Thiringer, M. Bongiorno and G. Le Godec, IGBT Power Stack Integrity Assessment Method for High-Power Magnet Supplies, accepted for publication in IEEE Transactions on Power Electronics
Thermal stressing mitigation possibility intended for a DC-current magnet supply based on high power IGBT modules
2017 19th European Conference on Power Electronics and Applications,; (2017)
Paper i proceeding
Current Sharing inside a High Power IGBT Module at the Negative Temperature Coefficient Operating Region
18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe, Karlsruhe, Germany, 5-9 September 2016,; (2016)
Paper i proceeding
P. Asimakopoulos, K. Papastergiou, “High Voltage Supply for Particle Accelerators based on Modular Multilevel Converters”, International Particle Accelerators Conference, IPAC16, South Korea, 2016
Heat sink design considerations in medium power electronic applications with long power cycles
17th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2015, Geneva, Switzerland, 8-10 September,; (2015)
Paper i proceeding
The core of a power electronic converter is the transistor, which, in this case, is the Insulated Gate Bipolar Transistor (IGBT). The thermal stressing of the IGBT, due to the conduction of high electrical current, results in the aging of the device and challenges the reliability of the power electronic converter. Considering that there are several IGBTs per converter, the importance of aging detection before the IGBT failure is of utmost importance.
In this work, a method is presented to detect the aging of IGBTs and to make possible to replace them before a failure occurs. This method for the IGBTs’ health evaluation is applied both during the testing phase of the power electronic converter right before installation as well as during scheduled service stops. Moreover, design and operation possibilities for the power electronic converter are discussed targeting the thermal stressing mitigation and the lifetime extension of the IGBTs.
Övrig annan teknik
Annan elektroteknik och elektronik
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4537
Room EA. Hörsalsvägen 11
Opponent: Dr Nicolas Degrenne, Mitsubishi Corporate Center in Rennes, France