EPE Association: EPE 2016 - DS2a: Power System Integration, Packaging & Thermal Management

EPE 2016 - DS2a: Power System Integration, Packaging & Thermal Management
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 01: Devices, Packaging and System Integration > EPE 2016 - DS2a: Power System Integration, Packaging & Thermal Management

   [return to parent folder]

   Analysis of PCB Embedded Power Semiconductors for a 30 kW Boost PFC Converter
By Jonas WYSS [View]
[Download]

Abstract: Packages of power semiconductors have considerable influence regarding the thermal impedance, the parasitic inductance, which affects the switching losses, and the reliability. In this paper, the performance of a phase leg of a PFC rectifier with PCB embedded power semiconductors is investigated. The mechanical stress in the PCB is analyzed by a FEM simulation and PCB design guidelines are given. The thermal impedance, parasitic inductance and switching losses of a real test setup are measured and compared with commercial modules. Based on this data, an optimization of a PFC rectifier with respect to volume, including the EMI filter, is performed for a converter using PCB embedded power semiconductors and compared to a converter using power semiconductors with conventional packaging. The converter using PCB embedded power semiconductors achieves a 21\% lower volume compared to a converter using power semiconductors with conventional packaging.

   Application issues of an online temperature estimation method in a high-power 4.5 kV IGBT module based on the gate-emitter threshold voltage
By Martin HOEER [View]
[Download]

Abstract: A method for estimating the junction temperature based on the static and quasi-static gate-emitter thresh-old voltage has been previously presented. However, several questions that remained open, such as thephysical meaning of the estimated temperature and in_uence of external parameters in the temperatureestimation, are now addressed in this paper. If devices are paralleled the proposed method extracts thelowest threshold voltage and therefore the highest temperature. The in_uence of unequal temperaturedistribution among the dies of a 4.5 kV/1.2 kA IGBT module is investigated as well as the in_uence ofa variation of the threshold voltage of individual chips and among different modules of the same devicefamily. Additionally to these device speci_c variations the in_uence of the integrated gate resistors isinvestigated and the feasibility for an industrial application is discussed.

   Connector-less SiC power modules with integrated shunts - low-profile design for low inductance and low cost -
By Michael MEISSER [View]
[Download]

Abstract: This paper presents the design, manufacture and characterization of connector-less 1200 V SiC MOSFET half-bridge power modules based on AlN DCB substrate. The modules contain four MOSFETs and no external antiparallel diodes. They are rated for a current of 40 A and include a shunt. Static and dynamic measurement results are presented. Multiphysics simulations are used to validate the measured data. The modules show a power path inductance below 3 nH. The power rating of the implemented chip shunt resistors is sufficient for the performed characterizations but requires revision. The switching loss at turn-on is 340 µJ at 23 A, 800 V, the turn-off loss is well below 50 µJ, principally allowing MHz operation in resonant mode.

   Developing innovative power modules for harsh environments: a skillful combination of technological breakthroughs and disruptive power mechatronics processes
By Sebastien OGE [View]
[Download]

Abstract: The design to cost is a major challenge for the practices of power modules' development especially when faced with very polymorphic demands. The technologies used are not always appropriate in view of the required technical specifications, or can be too expensive, or too basic. Developing a power module consists in making the best technological choices to fit the mission profile of an application; while serving the requirements at system level with a reasonable cost.

   Estimation of the lifetime consumption of power semiconductors due to power cycling in a photovoltaic inverter
By Artjom GRUBER [View]
[Download]

Abstract: This paper deals with the estimation of the lifetime consumption of power semiconductor modules due to power cycling with regard to a 125 kW photovoltaic inverter. The described calculation model takes into account a demanding photovoltaic mission profile, the operating point dependent behavior of the photovoltaic inverter, the amount of parallel semiconductor chips and the cooling system design. Different packaging technologies including state-of-the-art and new technologies with improved power cycling capability are considered based on power cycling diagrams published by semiconductor module manufacturers and the possible influence of the usage of silicon carbide instead of silicon chips is discussed. As a result, the calculated lifetime consumption as a function of the maximum junction temperature of the inverter design is presented.

   Evaluation of Ag-Sintering Pastes for the Die Attachment in Power Electronic Modules using Design of Experiments
By Bao Ngoc AN [View]
[Download]

Abstract: Silver sintering is a potential die attach technology to replace the solder technology for power electronic systems. A design of experiments (DoE) is performed in order to investigate the influences of sinter parameters as sinter pressure, temperature, duration, drying temperature and the interactions of these parameters on the shear strength of the Ag-sinter connection. Four sinter pastes have been evaluated. All significant parameters and parameter interactions are identified in order to derive a quadratic model function used to fit the measured shear values. This fitted function predicts the shear strength as a function of the significant parameters and, moreover, the function is used to determine the optimal sinter parameter space. The shear tests reveal that for three tested sinter pastes an excellent average shear result exceeding 90 MPa is achieved. One sinter paste outperforms these results by an average shear strength of 121 MPa. The DoE shows that all sinter pastes are significantly dependent on the sinter pressure and sinter temperature. However one sinter paste is influenced by the drying temperature and a second sinter paste is independent of the drying temperature as well as the sinter duration.

   High Thermal Conductance AlN Power Module with Hybrid Integrated Gate Drivers and SiC Trench MOSFETs for 2 kW Single-Phase PV Inverter
By Stefan MOENCH [View]
[Download]

Abstract: Silicon carbide (SiC) trench MOSFET half-bridge and full-bridge power modules with hybrid integrated gate drivers on aluminium nitride (AlN) substrate were designed with electro-thermal co-simulation and soldered on an aluminium heatsink, achieving 0.3 K/W junction-to-heatsink thermal resistance. A 2 kW single-stage PV-inverter with active energy-buffer was built around the modules, achieving a weighted CEC efficiency of 95.4\% and power density of 3.14 kW/l at a switching frequency of 100 kHz. The gate driver and bootstrap circuit are hybrid integrated on the power module for low parasitic gate-loop inductance. Electro-thermal co-simulation reveals a low transient temperature ripple of 6 K during the 60 Hz grid-frequency cycles at full load.

   Investigation of the Turn-on Behaviour of Silicon pin-Diodes and SiC-Schottky-Diodes and its Impact on the Anti-parallel IGBT
By Sarah RUGEN [View]
[Download]

Abstract: At high switching speeds silicon pin-diodes can show a significant forward recovery voltage, which appears as a reverse voltage over the anti-parallel IGBT. The avalanche breakdown of the IGBT floods its base-region with electron-hole-plasma, which is extracted when the diode is turned-off again after a while and contributes to the diode's reverse recovery peak. This effect increases the losses and endangers the IGBT because it is designed neither for a reverse avalanche breakdown nor for a reverse recovery. This work investigates the turn-on behaviour of silicon pin-diodes and SiC-Schottky-diodes (SBD) and their influence on the IGBT by means of measurements and mixed-mode simulations. The measurements were done on a 1000 A, 1700 V PrimePACK3 half-bridge module and on a special set-up with a discrete IGBT and a discrete diode (both with a rating of 20 A, 1200 V) to investigate the interaction between the two devices. At the end it turns out that the IGBT is indeed doing a reverse recovery, if it had been flooded during diode turn-on. The effect is rather small with the investigated 1200 V and 1700 V devices but it is much more severe for higher voltage classes. Using a unipolar SiC-Schottky-diode removes the turn-on overvoltage (but not the inevitable inductive component) and the stress on the IGBT. This way, the switching speed can be further increased and losses can be reduced.

   Long term short-circuit stability in Press-pack IGBTs
By Frank WAKEMAN [View]
[Download]

Abstract: The Press-pack IGBTs is ideally suited to applications where series operation is required; this quality is of particular interest for HVDC applications where several 100 devices may be required in a single switch. To ensure continued operation between maintenance cycles it is essential that the device fails to a stable short circuit. An experiment has been conducted and is reported in this paper to observe this characteristic over a period of 8000 hours. To simulate the real environment of an application selected die are pre-damaged in each device before encapsulation. The devices are then subjected to a large energy discharge after encapsulation. Results from the experiment show that the short circuit developed in the devices prior to the 8000 hour test remain stable, with voltage drops comparable to an operational device.

   Mitigation of Challenges in Automotive Power Module Packaging by Dual Sided Cooling
By Yangang WANG [View]
[Download]

Abstract: Packaging of power semiconductor module is facing huge challenges from automotive customers in terms of performance, temperature, reliability, weight, volume and cost etc. It is believed that power module structure, material and assembly technology are key factors for mitigating the challenges. Among of them, the cooling structure and of the module is of most importance to address these issues. In this paper, the dual sided cooling module for Hybrid and Electric Vehicles (HEV/EV) is proposed as an effective methodology for addressing these automotive level challenges. It is found that the thermal performance are improved significantly by cooling the module on both sides, which enhances the electrical performance at high power, high switching speed and improves thermal stability. The electrical performance and reliability are further improved by wire bondless interconnection and ultrasonic welding for terminals. By eliminating the baseplate in the module, the weight, volume and cost are reduced accordingly.

   Optimization Tool for Direct Water Cooling System of High Power IGBT Modules
By Amir Sajjad BAHMAN [View]
[Download]

Abstract: Thermal management of power electronic devices is essential for reliable system performance especially at high power levels. Since even the most efficient electronic circuit becomes hot because of ohmic losses, it is clear that cooling is needed in electronics and even more as the power increases. One of the most important activities in the thermal management and reliability improvement is the cooling system design. As industries are developing smaller power devices with higher power densities, optimized design of cooling systems with minimum thermal resistance and pressure drop become important issue for thermal design engineers. This paper aims to present a user friendly optimization tool for direct water cooling system of a high power module which enables the cooling system designer to identify the optimized solution depending on customer load profiles and available pump power. CFD simulations are implemented to find best solution for each scenario.

   Power cycle lifetime improvement by reducing thermal stress of a new dual HVIGBT module
By SAKAI YASUHIRO [View]
[Download]

Abstract: HVIGBT (High Voltage Insulated Gate Bipolar Transistor) modules are installed in traction drive applications and large industrial motor drive applications, so they require high power density and reliability. Enhancing power density of power modules increases thermal stress and especially reduces power cycle lifetime. This paper describes the design approach for reducing thermal stress by reducing thermal resistance of the module.

   Requirements for Circuit Components of Single-Phase Inverter Applied with Power Decoupling Capability toward High Power Density
By Jun-ichi ITOH [View]
[Download]

Abstract: This paper discusses how to achieve high power density with high efficiency for a single-phase inverter with an active power decoupling circuit. In conventional PV inverters, bulky electrolytic capacitors are connected to DC-link in order to absorb power pulsation with twice the grid frequency. On the other hand, in the active power decoupling circuit, the small capacitor can be used. However, the additional inductors and switching devices are necessary. Thus, the power density of the active power decoupling circuit is reduced. In this paper, the Pareto optimization of power density and efficiency is used to clarify the maximum power density points of the power decoupling circuits. As a result, the maximum power density of the conventional boost type active buffer, which connects a boost chopper to DC-link, is 90\% of that of electrolytic capacitor topology. In addition, this paper proposes a DC-DC converter with the power decoupling capability in order to achieve higher power density than that of the passive topology. The proposed circuit, which requires no additional inductor for the power decoupling circuit, uses discontinuous current mode (DCM) for the power decoupling capability. As a result, the maximum power density is obtained to 1.1 times higher than that of passive topology. However, the total loss of switching devices is 1.5 times higher. Thus, in order to surpass the efficiency of the passive topology by the active power decoupling, the switching device is required to reduce the total loss by 35\% compared to the present products.

   Study of the Packaging Effect on Blocking Voltage of Power Devices During Durability Test
By NAOKI SAKURAI [View]
[Download]

Abstract: We investigated why the blocking voltages of a power device are lowered during a durability test through a device simulation called Technology Computer Aided Design (TCAD) and measurements using the optical beam induced current (OBIC) method. We found that the spread of the depletion layer caused by the bonding wire is what decreased the blocking voltage.

   Temperature Control System using a Hybrid Discontinous Modulation Technique to improve the Lifetime of IGBT Power Modules
By Julian WOELFLE [View]
[Download]

Abstract: This paper presents a model based junction temperature control system to increase the expectedlifetime of IGBT power modules by using a hybrid discontinuous modulation technique. Thismodulation technique offers the possibility to influence the switching losses and is therefore used as acorrecting variable for controlling the junction temperatures of IGBT power modules.

   Test Bench for Thermal Cycling of 10 kV Silicon Carbide Power Modules
By Kristian FREDERIKSEN [View]
[Download]

Abstract: This paper presents a test bench for lifetime investigation of 10 kV silicon carbide power modules.The test bench subjects high voltage switching operation to the modules while power cycling.Thus both a thermal and electrical operating point is emulated. The power cycling setup featuresof!line measurement of on-state voltages and direct real-time measurement of die surface temperatures,enabled by fiber optical sensors, which are built into the power modules. A thermalmodel of the module prototypes, based on the temperature measurements, is established. Independentverification steps have been made to validate the performance of the on-state voltagemeasurement and the thermal model. Issues are revealed in the form of common mode currentsin gate drive supply, which should be remedied. Finally a new operating point for power cyclingis suggested to better stress the power modules.

EPE 2016 - DS2a: Power System Integration, Packaging & Thermal Management
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 01: Devices, Packaging and System Integration > EPE 2016 - DS2a: Power System Integration, Packaging & Thermal Management
	[return to parent folder]

	Analysis of PCB Embedded Power Semiconductors for a 30 kW Boost PFC Converter By Jonas WYSS	[View] [Download]
Abstract: Packages of power semiconductors have considerable influence regarding the thermal impedance, the parasitic inductance, which affects the switching losses, and the reliability. In this paper, the performance of a phase leg of a PFC rectifier with PCB embedded power semiconductors is investigated. The mechanical stress in the PCB is analyzed by a FEM simulation and PCB design guidelines are given. The thermal impedance, parasitic inductance and switching losses of a real test setup are measured and compared with commercial modules. Based on this data, an optimization of a PFC rectifier with respect to volume, including the EMI filter, is performed for a converter using PCB embedded power semiconductors and compared to a converter using power semiconductors with conventional packaging. The converter using PCB embedded power semiconductors achieves a 21\% lower volume compared to a converter using power semiconductors with conventional packaging.

	Application issues of an online temperature estimation method in a high-power 4.5 kV IGBT module based on the gate-emitter threshold voltage By Martin HOEER	[View] [Download]
Abstract: A method for estimating the junction temperature based on the static and quasi-static gate-emitter thresh-old voltage has been previously presented. However, several questions that remained open, such as thephysical meaning of the estimated temperature and in_uence of external parameters in the temperatureestimation, are now addressed in this paper. If devices are paralleled the proposed method extracts thelowest threshold voltage and therefore the highest temperature. The in_uence of unequal temperaturedistribution among the dies of a 4.5 kV/1.2 kA IGBT module is investigated as well as the in_uence ofa variation of the threshold voltage of individual chips and among different modules of the same devicefamily. Additionally to these device speci_c variations the in_uence of the integrated gate resistors isinvestigated and the feasibility for an industrial application is discussed.

	Connector-less SiC power modules with integrated shunts - low-profile design for low inductance and low cost - By Michael MEISSER	[View] [Download]
Abstract: This paper presents the design, manufacture and characterization of connector-less 1200 V SiC MOSFET half-bridge power modules based on AlN DCB substrate. The modules contain four MOSFETs and no external antiparallel diodes. They are rated for a current of 40 A and include a shunt. Static and dynamic measurement results are presented. Multiphysics simulations are used to validate the measured data. The modules show a power path inductance below 3 nH. The power rating of the implemented chip shunt resistors is sufficient for the performed characterizations but requires revision. The switching loss at turn-on is 340 µJ at 23 A, 800 V, the turn-off loss is well below 50 µJ, principally allowing MHz operation in resonant mode.

	Developing innovative power modules for harsh environments: a skillful combination of technological breakthroughs and disruptive power mechatronics processes By Sebastien OGE	[View] [Download]
Abstract: The design to cost is a major challenge for the practices of power modules' development especially when faced with very polymorphic demands. The technologies used are not always appropriate in view of the required technical specifications, or can be too expensive, or too basic. Developing a power module consists in making the best technological choices to fit the mission profile of an application; while serving the requirements at system level with a reasonable cost.

	Estimation of the lifetime consumption of power semiconductors due to power cycling in a photovoltaic inverter By Artjom GRUBER	[View] [Download]
Abstract: This paper deals with the estimation of the lifetime consumption of power semiconductor modules due to power cycling with regard to a 125 kW photovoltaic inverter. The described calculation model takes into account a demanding photovoltaic mission profile, the operating point dependent behavior of the photovoltaic inverter, the amount of parallel semiconductor chips and the cooling system design. Different packaging technologies including state-of-the-art and new technologies with improved power cycling capability are considered based on power cycling diagrams published by semiconductor module manufacturers and the possible influence of the usage of silicon carbide instead of silicon chips is discussed. As a result, the calculated lifetime consumption as a function of the maximum junction temperature of the inverter design is presented.

	Evaluation of Ag-Sintering Pastes for the Die Attachment in Power Electronic Modules using Design of Experiments By Bao Ngoc AN	[View] [Download]
Abstract: Silver sintering is a potential die attach technology to replace the solder technology for power electronic systems. A design of experiments (DoE) is performed in order to investigate the influences of sinter parameters as sinter pressure, temperature, duration, drying temperature and the interactions of these parameters on the shear strength of the Ag-sinter connection. Four sinter pastes have been evaluated. All significant parameters and parameter interactions are identified in order to derive a quadratic model function used to fit the measured shear values. This fitted function predicts the shear strength as a function of the significant parameters and, moreover, the function is used to determine the optimal sinter parameter space. The shear tests reveal that for three tested sinter pastes an excellent average shear result exceeding 90 MPa is achieved. One sinter paste outperforms these results by an average shear strength of 121 MPa. The DoE shows that all sinter pastes are significantly dependent on the sinter pressure and sinter temperature. However one sinter paste is influenced by the drying temperature and a second sinter paste is independent of the drying temperature as well as the sinter duration.

	High Thermal Conductance AlN Power Module with Hybrid Integrated Gate Drivers and SiC Trench MOSFETs for 2 kW Single-Phase PV Inverter By Stefan MOENCH	[View] [Download]
Abstract: Silicon carbide (SiC) trench MOSFET half-bridge and full-bridge power modules with hybrid integrated gate drivers on aluminium nitride (AlN) substrate were designed with electro-thermal co-simulation and soldered on an aluminium heatsink, achieving 0.3 K/W junction-to-heatsink thermal resistance. A 2 kW single-stage PV-inverter with active energy-buffer was built around the modules, achieving a weighted CEC efficiency of 95.4\% and power density of 3.14 kW/l at a switching frequency of 100 kHz. The gate driver and bootstrap circuit are hybrid integrated on the power module for low parasitic gate-loop inductance. Electro-thermal co-simulation reveals a low transient temperature ripple of 6 K during the 60 Hz grid-frequency cycles at full load.

	Investigation of the Turn-on Behaviour of Silicon pin-Diodes and SiC-Schottky-Diodes and its Impact on the Anti-parallel IGBT By Sarah RUGEN	[View] [Download]
Abstract: At high switching speeds silicon pin-diodes can show a significant forward recovery voltage, which appears as a reverse voltage over the anti-parallel IGBT. The avalanche breakdown of the IGBT floods its base-region with electron-hole-plasma, which is extracted when the diode is turned-off again after a while and contributes to the diode's reverse recovery peak. This effect increases the losses and endangers the IGBT because it is designed neither for a reverse avalanche breakdown nor for a reverse recovery. This work investigates the turn-on behaviour of silicon pin-diodes and SiC-Schottky-diodes (SBD) and their influence on the IGBT by means of measurements and mixed-mode simulations. The measurements were done on a 1000 A, 1700 V PrimePACK3 half-bridge module and on a special set-up with a discrete IGBT and a discrete diode (both with a rating of 20 A, 1200 V) to investigate the interaction between the two devices. At the end it turns out that the IGBT is indeed doing a reverse recovery, if it had been flooded during diode turn-on. The effect is rather small with the investigated 1200 V and 1700 V devices but it is much more severe for higher voltage classes. Using a unipolar SiC-Schottky-diode removes the turn-on overvoltage (but not the inevitable inductive component) and the stress on the IGBT. This way, the switching speed can be further increased and losses can be reduced.

	Long term short-circuit stability in Press-pack IGBTs By Frank WAKEMAN	[View] [Download]
Abstract: The Press-pack IGBTs is ideally suited to applications where series operation is required; this quality is of particular interest for HVDC applications where several 100 devices may be required in a single switch. To ensure continued operation between maintenance cycles it is essential that the device fails to a stable short circuit. An experiment has been conducted and is reported in this paper to observe this characteristic over a period of 8000 hours. To simulate the real environment of an application selected die are pre-damaged in each device before encapsulation. The devices are then subjected to a large energy discharge after encapsulation. Results from the experiment show that the short circuit developed in the devices prior to the 8000 hour test remain stable, with voltage drops comparable to an operational device.

	Mitigation of Challenges in Automotive Power Module Packaging by Dual Sided Cooling By Yangang WANG	[View] [Download]
Abstract: Packaging of power semiconductor module is facing huge challenges from automotive customers in terms of performance, temperature, reliability, weight, volume and cost etc. It is believed that power module structure, material and assembly technology are key factors for mitigating the challenges. Among of them, the cooling structure and of the module is of most importance to address these issues. In this paper, the dual sided cooling module for Hybrid and Electric Vehicles (HEV/EV) is proposed as an effective methodology for addressing these automotive level challenges. It is found that the thermal performance are improved significantly by cooling the module on both sides, which enhances the electrical performance at high power, high switching speed and improves thermal stability. The electrical performance and reliability are further improved by wire bondless interconnection and ultrasonic welding for terminals. By eliminating the baseplate in the module, the weight, volume and cost are reduced accordingly.

	Optimization Tool for Direct Water Cooling System of High Power IGBT Modules By Amir Sajjad BAHMAN	[View] [Download]
Abstract: Thermal management of power electronic devices is essential for reliable system performance especially at high power levels. Since even the most efficient electronic circuit becomes hot because of ohmic losses, it is clear that cooling is needed in electronics and even more as the power increases. One of the most important activities in the thermal management and reliability improvement is the cooling system design. As industries are developing smaller power devices with higher power densities, optimized design of cooling systems with minimum thermal resistance and pressure drop become important issue for thermal design engineers. This paper aims to present a user friendly optimization tool for direct water cooling system of a high power module which enables the cooling system designer to identify the optimized solution depending on customer load profiles and available pump power. CFD simulations are implemented to find best solution for each scenario.

	Power cycle lifetime improvement by reducing thermal stress of a new dual HVIGBT module By SAKAI YASUHIRO	[View] [Download]
Abstract: HVIGBT (High Voltage Insulated Gate Bipolar Transistor) modules are installed in traction drive applications and large industrial motor drive applications, so they require high power density and reliability. Enhancing power density of power modules increases thermal stress and especially reduces power cycle lifetime. This paper describes the design approach for reducing thermal stress by reducing thermal resistance of the module.

	Requirements for Circuit Components of Single-Phase Inverter Applied with Power Decoupling Capability toward High Power Density By Jun-ichi ITOH	[View] [Download]
Abstract: This paper discusses how to achieve high power density with high efficiency for a single-phase inverter with an active power decoupling circuit. In conventional PV inverters, bulky electrolytic capacitors are connected to DC-link in order to absorb power pulsation with twice the grid frequency. On the other hand, in the active power decoupling circuit, the small capacitor can be used. However, the additional inductors and switching devices are necessary. Thus, the power density of the active power decoupling circuit is reduced. In this paper, the Pareto optimization of power density and efficiency is used to clarify the maximum power density points of the power decoupling circuits. As a result, the maximum power density of the conventional boost type active buffer, which connects a boost chopper to DC-link, is 90\% of that of electrolytic capacitor topology. In addition, this paper proposes a DC-DC converter with the power decoupling capability in order to achieve higher power density than that of the passive topology. The proposed circuit, which requires no additional inductor for the power decoupling circuit, uses discontinuous current mode (DCM) for the power decoupling capability. As a result, the maximum power density is obtained to 1.1 times higher than that of passive topology. However, the total loss of switching devices is 1.5 times higher. Thus, in order to surpass the efficiency of the passive topology by the active power decoupling, the switching device is required to reduce the total loss by 35\% compared to the present products.

	Study of the Packaging Effect on Blocking Voltage of Power Devices During Durability Test By NAOKI SAKURAI	[View] [Download]
Abstract: We investigated why the blocking voltages of a power device are lowered during a durability test through a device simulation called Technology Computer Aided Design (TCAD) and measurements using the optical beam induced current (OBIC) method. We found that the spread of the depletion layer caused by the bonding wire is what decreased the blocking voltage.

	Temperature Control System using a Hybrid Discontinous Modulation Technique to improve the Lifetime of IGBT Power Modules By Julian WOELFLE	[View] [Download]
Abstract: This paper presents a model based junction temperature control system to increase the expectedlifetime of IGBT power modules by using a hybrid discontinuous modulation technique. Thismodulation technique offers the possibility to influence the switching losses and is therefore used as acorrecting variable for controlling the junction temperatures of IGBT power modules.

	Test Bench for Thermal Cycling of 10 kV Silicon Carbide Power Modules By Kristian FREDERIKSEN	[View] [Download]
Abstract: This paper presents a test bench for lifetime investigation of 10 kV silicon carbide power modules.The test bench subjects high voltage switching operation to the modules while power cycling.Thus both a thermal and electrical operating point is emulated. The power cycling setup featuresof!line measurement of on-state voltages and direct real-time measurement of die surface temperatures,enabled by fiber optical sensors, which are built into the power modules. A thermalmodel of the module prototypes, based on the temperature measurements, is established. Independentverification steps have been made to validate the performance of the on-state voltagemeasurement and the thermal model. Issues are revealed in the form of common mode currentsin gate drive supply, which should be remedied. Finally a new operating point for power cyclingis suggested to better stress the power modules.