Power semiconductor devices are key components in all power electronic systems, particularly in hybrid, electric, and fuel cell vehicles. This paper reviews the system requirement and latest development of power semiconductor devices including IGBTs, freewheeling diodes, and advanced power module technology in relating to electric vehicle applications. State-of-the-art silicon device technologies, their future trends, and theoretical limits are discussed. Emerging wide bandgap semiconductor devices such as SiC devices and their potential applications in electric vehicles are also reviewed

Power Semiconductor Devices for Hybrid, Electric, and Fuel Cell Vehicles

A review of recent advances in power electronic packaging is presented based on the development of power device integration. The presentation will cover in more detail how advances in both semiconductor content and power advanced package design and materials have co-enabled significant advances in power device capability during recent years. Extrapolating the same trends in representative areas for the remainder of the decade serves to highlight where further improvement in materials and techniques can drive continued enhancements in usability, efficiency, reliability and overall cost of power semiconductor solutions. Along with new power packaging development, the role of modeling is key to assure successful package design. An overview of the power package modeling is presented. Challenges of power semiconductor packaging and modeling in both next generation design and assembly processes are presented and discussed.

Trends of Power Electronic Packaging and Modeling

Power electronic packaging is one of the fastest changing areas of technology in the power electronic industry due to the rapid advances in power integrated circuit (IC) fabrication and the demands of a growing market in almost all areas of power electronic application such as portable electronics, consumer electronics, home electronics, computing electronics, automotive, railway and high/strong power industry. However, due to the intrinsic high power dissipation, the performance requirement for power products are extremely high, especially in handling harsh thermal and electrical environments. The design rules and material and structure layout of power packaging are quite different from regular IC packaging. This talk will present a state-of-art and in-depth overview of recent advances, challenges and opportunities in power electronic packaging design and modeling. A review of recent advances in power electronic packaging is presented based on the development of power device integration. The talk will cover in more detail how challenges in both semiconductor content and advanced power package design and materials have co-enabled significant advances in power device capability during recent years. Extrapolating the same trends in representative areas for the remainder of the decade serves to highlight where further improvement in materials and techniques can drive continued enhancements in usability, efficiency, reliability and overall cost of power semiconductor solutions. Along with new power packaging development, modeling is a key to assure successful package design. An overview of the power package modeling is presented. Challenges of power semiconductor packaging and modeling in both next generation design and assembly processes are presented and discussed.

Challenges of power electronic packaging and modeling

This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components and thermal management. In addition to the cornerstones, the spatial integration of converter components is considered as it is also important for high power density. The size reduction in passives is obtained by increasing the operating frequency. On the other hand, an increase of operating frequency yields also higher losses in passive components themselves. Therefore, the thesis addresses the power loss in windings of magnetic components with special attention to the transformer windings. Integration of several passive components into a single component is also considered as the means to increase the power density. The main challenge is the integration of components at the considered high power levels. A high operating frequency results in a substantial increase of switching losses in active components. The higher losses yield reduced efficiency and require larger heatsinks which consequently reduce the effect of the higher operating frequency on the overall power density. In this thesis, the power loss in active components is reduced by applying so called Zero-Voltage-Switching Quasi-Zero-Current-Switching topology. The heat generated inside converter components must be removed to prevent them from overheating. Performing this task becomes more difficult as the power density increases because of higher power dissipated in a smaller volume. The thesis considers thermal management of a power converter on component, converter and system level. Each of the levels is addressed separately and adequate heat removal methods and concepts are proposed. Spatial integration of converter components is important to obtain a high power density as well. The key to the successful integration of components is to make design choices which result in components of compatible dimensions and shapes. Basic guidelines that should serve as an aid in the design of high power density high-power converters are discussed in this thesis. The operating conditions and requirements vary with the power level processed by a power converter. Therefore, the scalability of the design concepts and approaches is important for their practical implementation in the wide range of considered applications. This thesis briefly discusses scaling up with respect to power density and performance of the converter components. The ability of achieving high power densities in high power is demonstrated on a 50 kW converter prototype. The reached power density is in order of 11.2 kW/litre with water cooling and 6.6 kW/litre with forced air cooling. It is also shown that by designing for high power density, the efficiency might not need to suffer. The measured efficiency of the final converter prototype is as high as 97.5 % in a broad load range.

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Electronic DC transformer with high power density

Spray cooling is a high heat flux removal technique considered for systems such as advanced lasers and high power density electronics. Several experiments have been conducted using spray cooling in recent years and various designs of spray cooling devices are continually emerging. At this time, one of NASA’s missions is to enhance future space science capabilities through the application of power lasers and electronics. However, the usage of systems having high heat fluxes can only be achieved with the corresponding development of high power thermal control systems. For the reliable performance of these high‐heat‐flux systems, proper thermal management is imperative. The study presented reviews the fabrication of a spray cooling system aimed at addressing issues pertinent to space applications. These issues include heat flux capability, orientation, and volumetric packaging. Computer modeling of spray cooling under microgravity conditions as well as comparison to the analogous 1‐g condition was also performed to gain insight into microgravity behavior.

Spray Cooling Development Effort for Microgravity Environments

The heat flux requirements of present power electronics systems are exceeding 100 W/cm2 and are predicted to reach the 1000 W/cm2 range in the near future. Spray cooling is a cooling technology that can provide such enormous cooling demands. Direct spray cooling of power devices (e.g., IGBTs) that are conventionally wire-bonded creates long-term reliability problems. So in order to achieve the expected future heat load demands and improve the reliability of the system there is a need for novel packaging methodologies. This paper reports on an innovative packaging methodology and a test vehicle that demonstrates the potential of spray cooling power electronics. This paper describes the proposed methodology as well as the spraying parameters that affect the cooling

A novel packaging methodology for spray cooling of power semiconductor devices using dielectric liquids

The Electrical Engineering Department at University of Arkansas has been building considerable strength in Energy Efficiency/Renewable Energy Systems, Mixed-Signal, and Wireless Packaging areas. This effort is in coordination with critical other Departments within the College of Engineering; specifically Industrial Engineering and Mechanical Engineering Departments, in addition to the Physics Department within the College of Arts and Science. The High Density Electronics Center (HiDEC), established in 1992 with DARPA funds to conduct research on advanced electronic packaging technologies, enables the educators to interact within the various disciplines to achieve the set objectives of packaging in these areas. The paper will outline the mission of each area, the vision and objectives of the administration, the technical issues to be addressed, the technological challenges and barriers for the Department to face and overcome to make this vision a true reality, and the curriculum restructure. The paper will also outline how critical these strategic areas are for a national academic institution recognition and fulfillment of critical needs for our nation's global competitiveness.

R.P. Selvam

Papers

A novel packaging methodology for spray cooling of power semiconductor devices using dielectric liquids

Curriculum restructure to answer critical needs in packaging for energy efficiency/renewable energy systems, wireless, and mixed-signal systems areas