EPE Association: EPE 2018 - DS2b: Power System Integration, Packaging and Thermal Management

EPE 2018 - DS2b: Power System Integration, Packaging and Thermal Management
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 01: Devices, Packaging and System Integration > EPE 2018 - DS2b: Power System Integration, Packaging and Thermal Management

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   A Multi-Layer RC Thermal Model for Power Modules Adaptable to Different Operating Conditions and Aging
By Mohsen AKBARI [View]
[Download]

Abstract: Semiconductor devices are often the most vulnerable components of power electronics converters among which thermal failures are the most likely ones. Thus, more accurate but straightforward thermal models are needed to efficiently do actions such as lifetime prediction, thermal management, etc. This paper presents a Foster-type equivalent transient thermal model developed through finite element simulations for a commercial Si IGBT power module. Such thermal models can easily merge into circuit simulation programs and even can be employed as real-time temperature estimators. However, fixed thermal models may give large errors in different operating conditions. In addition, they become unable to satisfactorily estimate temperatures over time, because of the thermal aging phenomenon. Thus, in this study, the thermal model of the power module is developed to be adapted to different boundary conditions - ambient temperature, and cooling system - as well as thermal aging of solder joints, which is the most common failure in the power modules. Also, the thermal model features the effect of power loss, and the cross-coupling effect among nearby semiconductor dies. Comparisons with FEM verify the performance of the studied thermal model.

   Analyses of the unbalanced paralleled GaN HEMT transistors
By Van-Sang NGUYEN [View]
[Download]

Abstract: Today, GaN HEMT transistors are widely used, however, the nominal current of the available devices is limited. To achieve a higher current, paralleling GaN is an interesting solution. This work focuses on the effects of the unbalanced designs which are significant on the dynamic phenomenon also on the thermal issues. Simulations and experimental results are presenting.

   Analysis of natural convection cooling solutions for GaN HEMT transistors
By Xavier JORDA [View]
[Download]

Abstract: GaN HEMT power transistors have become an attractive option for high switching frequency converters in the 600 - 650 V breakdown voltage range. The high voltage and current variation rates involved in the commutation process of such devices in combination with the package terminals stray inductance introduce unwanted and dangerous over-voltages and oscillations. For this reason TO-247 or TO-220 packages typically used in the medium power range (for example for IGBTs and Super Junction MOSFETs) are avoided for discrete GaN HEMTs, which are mainly packaged in different surface mount (SMD) formats. In SMD packages, the stray inductances are in the range of the nH and below, but the heat extraction plane (typically a Cu thermal pad) is often at the same level than the electrical terminals, hindering the simultaneous optimum design of the electrical and thermal circuit layouts. This work analyses the high speed switching (i.e., optimum circuit layout) versus thermal management (i.e., low thermal resistanece) trade-off, comparing different options for cooling p-GaN HEMT transistors in a PG-DSO SMD package. Two approaches based only on natural convection have been considered: board-level and heatsink-based solutions. Comparison among the different cooling options has been quantified by means of the HEMT junction to ambient thermal impedance, evaluated with the devices assembled in test-vehicle PCB boards. The results provide information for practicing engineers who would like to have a point of reference for passive cooling solutions of discrete GaN HEMTs.

   Development of a GaN based Triple-Active-Bridge for DC nanogrid
By Nicola DELMONTE [View]
[Download]

Abstract: This work proposes an architecture of a DC nanogrid with a small PV plant, a battery as storage unit, and a three-port converter for low voltage distribution and the management of the electric energy flows. The main objective is to investigate the development of this converter using GaN power FETs. Here are presented the results of preliminary tests carried out using two different GaN FETs in the full bridges needed for the three-port converter. The aim is to identify the best components, among the ones commercially available, for efficiency and thermal design.

   High I2t reliable power modules with leadframe structure and RC-IGBT combination technologies
By Maruyama RYO [View]
[Download]

Abstract: This paper describes new results of I2t capability study for IGBT modules used for xEV power train applications. Combination matrix of RC-IGBT or the conventional FWD and leadframe or bondwires were investigated, and 2.4 times higher performance was obtained in combination of RC-IGBT and leadframe compared with that of FWD and bondwires.

   Low Jitter Voltage Controlled Oscillator and Gatedriver for VHF Switch Mode Power Supplies
By Jens HERTEL [View]
[Download]

Abstract: Decreasing size of consumer electronics pushes demands for higher power density and higher efficiency. Increased switching frequency can reduce the size, but generating MHz gate signals is nontrivial, e.g. due to jitter. We show a custom IC containing a low jitter VCO and gate driver, capable of driving MOSFETs at 5-35 MHz.

   Paralleling of High Power Dual Modules: Standard Building Block Design for Evaluation of Module Related Current Mismatch
By Jan WEIGEL [View]
[Download]

Abstract: This paper discusses the challenges of paralleling dual modules with special focus on the currently introduced half bridge modules with 100 mm * 140 mm footprint like LinPak, nHPD2, XHP2/3, LV/HV100, etc. Compared to conventional high power converters build up using single switches (e.g. 190 mm * 140 mm footprint) a higher number of paralleled dual modules (by a factor of 3 to 4) is required to achieve equivalent output power, needed e.g. for traction applications. This paper picks up known design features, required to avoid design related current imbalance and suggests a reference setup for the paralleling of high power dual modules to focus on current imbalances that are generated by semiconductor device characteristics. This reference setup is based on the uniform basic design idea by the device manufacturers, to put the parallel modules in a row and to design the converter, corresponding to the semiconductor module, as a strip line. Remaining design options are discussed with regard to gate control to conclude with a standardized reference design.

   Performance of Wide Band Gap Devices in Electric Vehicles Converters: A Case Study Evaluation
By Mohamed YOUSSEF [View]
[Download]

Abstract: This study investigates the usage of Gallium Nitride (GaN) and Silicon Carbide (SiC), in DC/DC converters; as an alternative to the conventional Si Converters exploiting their high switching capabilities with low losses. This work focuses mainly on the converter used in Electric vehicles for the purposes of charging the battery. A complete model has been developed and a comparison between using SiC and GaN has been performed to determine the viability of using each one in terms of temperature and converter losses. A case study of Nissan Leaf EV is being adopted as a proof of concept and a prototype for it was built in the lab. The experimental results regarding each component and their relationship with the simulation results. It was obvious that the simulation results match perfectly the experimental ones on a system-level basis.

   Practical approach of testing various thermal interface materials for power electronics
By Kristaps VITOLS [View]
[Download]

Abstract: Thermal interface material datasheets often contain information that is not easily usable for an application engineer. Simple field experiments can provide valuable hints to guide the selection of proper material. Practical testing and FEM simulation of various materials is performed and results are analyzed to reveal the differences between datasheet information and experimental results.

   Thermal performance analysis of GaN-based high-power converters
By Ander AVILA [View]
[Download]

Abstract: Gallium Nitride (GaN) devices are game-changing power electronics due to low conduction and switchingpower loss characteristics. However, their small size brings up new cooling challenges for its implementation in high-power converters. This paper compares thermal performance of different coolingconfigurations, looking for the optimal cooling solution to develop compact power converters based onGaN devices. The proposed thermal analysis and performance comparison are experimentally validatedcomparing top and bottom side cooling solutions.

EPE 2018 - DS2b: Power System Integration, Packaging and Thermal Management
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 01: Devices, Packaging and System Integration > EPE 2018 - DS2b: Power System Integration, Packaging and Thermal Management
	[return to parent folder]

	A Multi-Layer RC Thermal Model for Power Modules Adaptable to Different Operating Conditions and Aging By Mohsen AKBARI	[View] [Download]
Abstract: Semiconductor devices are often the most vulnerable components of power electronics converters among which thermal failures are the most likely ones. Thus, more accurate but straightforward thermal models are needed to efficiently do actions such as lifetime prediction, thermal management, etc. This paper presents a Foster-type equivalent transient thermal model developed through finite element simulations for a commercial Si IGBT power module. Such thermal models can easily merge into circuit simulation programs and even can be employed as real-time temperature estimators. However, fixed thermal models may give large errors in different operating conditions. In addition, they become unable to satisfactorily estimate temperatures over time, because of the thermal aging phenomenon. Thus, in this study, the thermal model of the power module is developed to be adapted to different boundary conditions - ambient temperature, and cooling system - as well as thermal aging of solder joints, which is the most common failure in the power modules. Also, the thermal model features the effect of power loss, and the cross-coupling effect among nearby semiconductor dies. Comparisons with FEM verify the performance of the studied thermal model.

	Analyses of the unbalanced paralleled GaN HEMT transistors By Van-Sang NGUYEN	[View] [Download]
Abstract: Today, GaN HEMT transistors are widely used, however, the nominal current of the available devices is limited. To achieve a higher current, paralleling GaN is an interesting solution. This work focuses on the effects of the unbalanced designs which are significant on the dynamic phenomenon also on the thermal issues. Simulations and experimental results are presenting.

	Analysis of natural convection cooling solutions for GaN HEMT transistors By Xavier JORDA	[View] [Download]
Abstract: GaN HEMT power transistors have become an attractive option for high switching frequency converters in the 600 - 650 V breakdown voltage range. The high voltage and current variation rates involved in the commutation process of such devices in combination with the package terminals stray inductance introduce unwanted and dangerous over-voltages and oscillations. For this reason TO-247 or TO-220 packages typically used in the medium power range (for example for IGBTs and Super Junction MOSFETs) are avoided for discrete GaN HEMTs, which are mainly packaged in different surface mount (SMD) formats. In SMD packages, the stray inductances are in the range of the nH and below, but the heat extraction plane (typically a Cu thermal pad) is often at the same level than the electrical terminals, hindering the simultaneous optimum design of the electrical and thermal circuit layouts. This work analyses the high speed switching (i.e., optimum circuit layout) versus thermal management (i.e., low thermal resistanece) trade-off, comparing different options for cooling p-GaN HEMT transistors in a PG-DSO SMD package. Two approaches based only on natural convection have been considered: board-level and heatsink-based solutions. Comparison among the different cooling options has been quantified by means of the HEMT junction to ambient thermal impedance, evaluated with the devices assembled in test-vehicle PCB boards. The results provide information for practicing engineers who would like to have a point of reference for passive cooling solutions of discrete GaN HEMTs.

	Development of a GaN based Triple-Active-Bridge for DC nanogrid By Nicola DELMONTE	[View] [Download]
Abstract: This work proposes an architecture of a DC nanogrid with a small PV plant, a battery as storage unit, and a three-port converter for low voltage distribution and the management of the electric energy flows. The main objective is to investigate the development of this converter using GaN power FETs. Here are presented the results of preliminary tests carried out using two different GaN FETs in the full bridges needed for the three-port converter. The aim is to identify the best components, among the ones commercially available, for efficiency and thermal design.

	High I2t reliable power modules with leadframe structure and RC-IGBT combination technologies By Maruyama RYO	[View] [Download]
Abstract: This paper describes new results of I2t capability study for IGBT modules used for xEV power train applications. Combination matrix of RC-IGBT or the conventional FWD and leadframe or bondwires were investigated, and 2.4 times higher performance was obtained in combination of RC-IGBT and leadframe compared with that of FWD and bondwires.

	Low Jitter Voltage Controlled Oscillator and Gatedriver for VHF Switch Mode Power Supplies By Jens HERTEL	[View] [Download]
Abstract: Decreasing size of consumer electronics pushes demands for higher power density and higher efficiency. Increased switching frequency can reduce the size, but generating MHz gate signals is nontrivial, e.g. due to jitter. We show a custom IC containing a low jitter VCO and gate driver, capable of driving MOSFETs at 5-35 MHz.

	Paralleling of High Power Dual Modules: Standard Building Block Design for Evaluation of Module Related Current Mismatch By Jan WEIGEL	[View] [Download]
Abstract: This paper discusses the challenges of paralleling dual modules with special focus on the currently introduced half bridge modules with 100 mm * 140 mm footprint like LinPak, nHPD2, XHP2/3, LV/HV100, etc. Compared to conventional high power converters build up using single switches (e.g. 190 mm * 140 mm footprint) a higher number of paralleled dual modules (by a factor of 3 to 4) is required to achieve equivalent output power, needed e.g. for traction applications. This paper picks up known design features, required to avoid design related current imbalance and suggests a reference setup for the paralleling of high power dual modules to focus on current imbalances that are generated by semiconductor device characteristics. This reference setup is based on the uniform basic design idea by the device manufacturers, to put the parallel modules in a row and to design the converter, corresponding to the semiconductor module, as a strip line. Remaining design options are discussed with regard to gate control to conclude with a standardized reference design.

	Performance of Wide Band Gap Devices in Electric Vehicles Converters: A Case Study Evaluation By Mohamed YOUSSEF	[View] [Download]
Abstract: This study investigates the usage of Gallium Nitride (GaN) and Silicon Carbide (SiC), in DC/DC converters; as an alternative to the conventional Si Converters exploiting their high switching capabilities with low losses. This work focuses mainly on the converter used in Electric vehicles for the purposes of charging the battery. A complete model has been developed and a comparison between using SiC and GaN has been performed to determine the viability of using each one in terms of temperature and converter losses. A case study of Nissan Leaf EV is being adopted as a proof of concept and a prototype for it was built in the lab. The experimental results regarding each component and their relationship with the simulation results. It was obvious that the simulation results match perfectly the experimental ones on a system-level basis.

	Practical approach of testing various thermal interface materials for power electronics By Kristaps VITOLS	[View] [Download]
Abstract: Thermal interface material datasheets often contain information that is not easily usable for an application engineer. Simple field experiments can provide valuable hints to guide the selection of proper material. Practical testing and FEM simulation of various materials is performed and results are analyzed to reveal the differences between datasheet information and experimental results.

	Thermal performance analysis of GaN-based high-power converters By Ander AVILA	[View] [Download]
Abstract: Gallium Nitride (GaN) devices are game-changing power electronics due to low conduction and switchingpower loss characteristics. However, their small size brings up new cooling challenges for its implementation in high-power converters. This paper compares thermal performance of different coolingconfigurations, looking for the optimal cooling solution to develop compact power converters based onGaN devices. The proposed thermal analysis and performance comparison are experimentally validatedcomparing top and bottom side cooling solutions.