With increased need for high power density, high efficiency and high temperature capabilities in aerospace and automotive applications, integrated motor drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This study reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the matrix converter, two-level bridge, three-level neutral point clamped and multiphase full bridge converters are also reviewed. Wide band gap devices like silicon carbide and gallium nitride and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented.

/pdf/integrated-motor-drives-state-of-the-art-and-future-trends-4rjgafc9l3.pdf

Integrated motor drives: state of the art and future trends

Semiconductor encapsulation is crucial to electronic packaging because it provides protection against mechanical stress, electrical breakdown, chemical erosions, α radiations, and so on. Conventional encapsulants are only applicable below 150 °C. However, with increasing demand for high-density and high-temperature packaging, encapsulants that are functional at or above 250 °C are required. In this paper, five types of encapsulants, including conformal coatings, underfills, molding compounds, potting compounds, and glob tops, are surveyed. First, recommended properties and selection criteria of each type of encapsulant are listed. Second, standard test methods for several crucial properties, including glass-transition temperature (T
 g
), coefficient of thermal expansion (CTE), dielectric strength, and so on are reviewed. Afterward, commercial products with high-operation temperature are surveyed. However, the results of the survey reveal a lack of high-temperature encapsulants. Therefore, this paper reviews recent progress in achieving encapsulants with both high-temperature capability and satisfactory properties. Material compositions other than epoxy, such as polyimide (PI), bismaleimide (BMI), and cyanate ester (CE), are potential encapsulants for high-temperature (250 °C) operation, although their CTE needs to be tailored to limit internal stress. Fillers are reported to be efficient in reducing the CTE. In addition, fillers may also have a beneficial impact on the thermal stability of silicone-based encapsulants, whose high-temperature capability is limited by their thermal instability.

Survey of High-Temperature Polymeric Encapsulants for Power Electronics Packaging

Performance of a 2 kW, 40 kHz, 270 V/500 V boost dc-dc power converter as a function of temperature is reported for the following power semiconductor device combinations: Si MOSFET and Si ultrafast diode, and SiC MOSFET and SiC Schottky diode. The test results clearly demonstrate the possibility of designing 200 degC power converters utilizing SiC power semiconductor devices

High temperature operation of a dc-dc power converter utilizing SiC power devices

Reliable use of commercial technology in high temperature environments

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor’s working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from −40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is 347.45 KHz / ℃ from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications.

https://www.mdpi.com/1424-8220/18/2/532/pdf

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor

Packaging of electronics for high temperature applications

Small signal commercial electronics have traditionally been designed to operate at temperatures below 125/spl deg/C. This has become a severe constraint in the development of next generation smart power electronic systems, such as remote actuators, point-of-use power supplies, and distributed high power control systems. These systems dissipate considerable heat and can operate in environments where the local ambient temperatures reach 200/spl deg/C. The ability to operate these systems without the need for active cooling is seen as a critical technology for the 21st century. The issues involved in designing silicon-based electronic systems for use at temperatures as high as 200/spl deg/C are presented in this work. The critical limiting components and packaging materials have been identified through design analyses conducted on commercially available aeronautic and automotive control modules. It is found that most standard components and packaging elements can be used up to 200/spl deg/C. However, capacitors, wire bonds, eutectic tin-lead solder joints, and FR-4 boards seriously degrade at temperatures around 200/spl deg/C. For these elements, alternative choices are recommended.

http://ieeexplore.ieee.org/iel4/5911/15764/00730698.pdf

L. Condra

Papers

Packaging of electronics for high temperature applications

Reliability concerns in high temperature electronic systems