Properties and applications of additively manufactured metallic cellular materials: A review

State-of-the-art in heat exchanger additive manufacturing

This article focuses on providing the laminated busbar design guidance for a three-level T-type neutral-point-clamped (3L-TNPC) inverter to achieve low stray inductance and balanced inductance distribution between paralleled power switches. As a result, equalized dynamic current sharing can be accomplished. To discover the design strategy, this article first derives the mutual-inductance-decoupled equivalent circuit for 3L-TNPC. Then, the effects of each inductance item on switching performance can be unveiled, and the parametric targets are then summarized. Accordingly, the busbar design considerations are discussed. A step-by-step busbar design procedure to achieve the aforementioned design targets is provided in the next. The design procedure starts from 2-D optimization to achieve the optimal component and terminal allocation, and then, it increases the optimization degree to 3-D. Using this design procedure, we proposed a novel double-side-end busbar structure to achieve the busbar stray inductance of 12.7 nH and the inductance differences between the paralleled switches to be less than 2 nH. Extensive experiments are carried out in the end to evaluate the design procedure and demonstrate the performance of the busbar.

Design and Evaluation of Laminated Busbar for Three-Level T-Type NPC Power Electronics Building Block With Enhanced Dynamic Current Sharing

Fundamentals Of Microsystems Packaging

A host of high-voltage-capable electronic packaging approaches have emerged in recent years for usage in next-generation power electronics. In this article, the focus is on the challenge of managing the thermal characteristics in these cutting edge packaging options, where power densities are exceeding 25 kW/L. Utilizing wide bandgap semiconductors like SiC and GaN can help reduce the thermal inefficiencies associated with conduction losses by using high-frequency switching topologies, but even so, when considering the demand of high voltage in mobile electrified systems, heat generation is still a primary limiting factor in widespread adoption. Accordingly, the increased power density results in much higher temperatures at the device and package level, which in turn reduces the reliability of such systems, in terms of thermal breakdown or thermomechanical strains within the packages. As a result, the design of cooling systems for these electronics has emerged as a key component to successful implementation, and effective thermal management schemes must be closely integrated with the electronic packaging for maximum benefit. This review looks at various thermal management approaches that have been demonstrated in electronic systems, with a specific emphasis on the challenges and needs for next-generation high-voltage power electronics.

A Review of Advanced Thermal Management Solutions and the Implications for Integration in High-Voltage Packages

Advances in manufacturing technologies and the recent explosion of materials and methods for creating additively manufactured devices has opened new avenues for novel heat sink designs that can be ...

Additive Manufacturing for Enhancing Thermal Dissipation in Heat Sink Implementation: A Review

This paper presents the design and evaluation of a phase-leg of power electronic building block (PEBB) with 150-kVA rated power by using 3-level T-type neutral-point-clamped (3L-TNPC) inverter for high-speed motor drives. Model-based pre-design evaluations and power module selections are first introduced to evaluate the design feasibility and improve efficiency. Based on the selected power modules, a novel busbar structure is proposed with a stray inductance of 11.2 nH. Besides these, a novel non-metallic cold plate is designed and evaluated. It shows less weight and improved common-mode noise than the traditional aluminum-cast cold plate. In the end of the paper, continuous tests are carried out to demonstrate the performance of the designed PEBB system. The measured peak efficiency is 99.45% with 30 kHz switching frequency and the measured specific power is 35.36 kW/kg.

Design and Evaluation of A 150 kVA SiC MOSFET Based Three Level TNPC Phase-leg PEBB for Aircraft Motor Driving Application

As high voltage, wide-band-gap power modules increase in power density with high switching frequency, they create localized hot spots and harmful electromagnetic interference (EMI). If not treated properly, these issues can drastically reduce the reliability of the devices. In this article, we propose a solution to address both of these challenges created by power module building blocks which are designed for use in a hybrid-electric aircraft traction inverter. Additive manufacturing is used to fabricate a nonmetallic jet impingement device to decrease power module temperatures. Moreover, the nonmetallic structure limits the accentuation of EMI created by the module operating at high switching frequencies. Conjugate heat transfer simulations are used to predict the thermal performance of the cooler. In this article, a reduction of maximum die temperatures is observed, along with an increase in temperature uniformity throughout the base plate. Experimental results show a minimum thermal resistance of 0.1 K/W and an average heat transfer coefficient up to 3600 W/m2.K at peak operation. Finally, EMI tests are performed to show a two orders of magnitude reduction of parasitic capacitance using the nonmetallic cooler compared with a metallic heat sink. This directly leads to a 25 dB decrease in the common mode noise.

Thermal and Electrical Performance in High-Voltage Power Modules With Nonmetallic Additively Manufactured Impingement Coolers

This study aims to provide an additive manufacturing-based pathway for addressing issues concerned with the reliability of high-density electronic packaging. It compares the performance of a non-metallic, additively manufactured heat spreader with that of a conventional cold plate. CFD software is first used to evaluate the heat spreaders with respect to cooling capability. Furthermore, the device is experimentally tested in a flow loop and its performance compared to that of the cold plate. Initial simulation results show the additively manufactured plastic heat sinks provide a uniform cooling profile and maintain lower maximum temperatures seen in the power module. Experimental results show a lower pressure drop seen is seen in the heat spreader over a wide range of flow rates. Moreover, the use of plastics shows a clear discount of EMI while keeping the material cost and the device weight at a reduced level.

Heat Transfer and Pressure Drop Performance of Additively Manufactured Polymer Heat Spreaders for Low-Weight Directed Cooling Integration in Power Electronics

\n With the increase of electronic device power density, thermal management and reliability are increasingly critical in the design of power electronic systems. First, increased density challenges the capability of conventional heat sinks to adequately dissipate heat. Second, higher frequency switching in high voltage, high current, wide bandgap power modules is creating intensified electromagnetic interference (EMI) challenges, in which metallic heat removal systems will couple and create damaging current ringing. Furthermore, mobile power systems require lightweight heat removal methods that satisfy the heat loads dissipated during operation. In this effort, we introduce an additive manufacturing (AM) pathway to produce custom heat removal systems using nonmetallic materials, which take advantage of impinging fluid heat transfer to enable efficient thermal management. Herein, we leverage the precision of additive manufacturing techniques in the development of three-dimensional optimized flow channels for achieving enhanced effective convective heat transfer coefficients. The experimental performance of convective heat removal due to liquid impingement is compared with conventional heat sinks, with the requirement of simulating the heat transfer needed by a high voltage inverter. The implementation of nonmetallic materials manufacturing is aimed to reduce electromagnetic interference in a low weight and reduced cost package, making it useful for mobile power electronics.

Reece Whitt

Papers

Additive Manufacturing for Enhancing Thermal Dissipation in Heat Sink Implementation: A Review

Design and Evaluation of A 150 kVA SiC MOSFET Based Three Level TNPC Phase-leg PEBB for Aircraft Motor Driving Application

Thermal and Electrical Performance in High-Voltage Power Modules With Nonmetallic Additively Manufactured Impingement Coolers

Heat Transfer and Pressure Drop Performance of Additively Manufactured Polymer Heat Spreaders for Low-Weight Directed Cooling Integration in Power Electronics

Additive Manufactured Impinging Coolant, Low Electromagnetic Interference, and Nonmetallic Heat Spreader: Design and Optimization