Electronics Packaging is among the most important disciplines within mechanical engineering. It incorporates numerous engineering sub disciplines, including thermal design and thermoelectric cooling. For a well-crafted Electronics Packaging design, it is essential that engineers from handheld electronics design firms to think about an array of options. Here are a selection of these techniques from the toolbox of the mechanical engineer to take into consideration during your electronic packaging design process.
Steady State Cooling
We typically base the electronic device’s thermal design on the assumption of steady-state. We establish a worst-case atmospheric temperature, at which we test the device and then use the device at this temperature for a period of time. A typical, though conservative temperature is 55. This is only a couple of degrees higher than the most high temperature recorded on Earth. However, consider that temperature difference causes heat transfer, or “Delta-T.” If you have to limit internal temperatures to 70 degrees Celsius, the test temperature of 55 yields only 15 percent of Delta T to power heat dissipation. By reducing the temperature of the test to 50 degrees, that is still extreme hot, will increase the delta-T by 20.
This is an increase of 33% in heat rejection. If you don’t get anything other than this information Be aware of this not to over-define the temperature in the air! A more realistic goal for your design’s thermal performance will yield an easier to manage and less expensive product.
The steady-state model serves as an ideal baseline to examine the most interesting issues that arise in the field of Electronics Packaging.
There are devices that we intend to run for short durations of time in extreme temperatures.For example, a “Black Box” (sometimes known as a “black box”) used on commercial aircrafts is intended to operate in 30 minutes at temperatures of 1,100 degrees Fahrenheit. This feat is accomplished using an extremely primitive method using a double-walled enclosure, and lots of insulation. Other devices, smaller in size employ a different method of operation.
Powerful Electronics Packaging in Extreme Environments
The industry of power electronics is responsible for the products that are used by billions of individuals such as televisions, smartphones as well as certain automotive parts as well as components of household and motors. With such a broad range of uses, numerous specifications are taken into consideration during the creation of these devices such as high energy and power density as well as price as well as safety of the customer. Arkansas Power Electronics International (APEI) an American-based firm is working on improving design concepts for Electronics Packaging power that manage the temperature of power electronics, improve efficiency, and reduce costs.
Designing Power Electronics for Optimal Thermal Management
A variety of factors affect the efficiency of these. For instance, optimal operating conditions might need a particular temperatures, voltage, and switching frequency , which when not maintained can cause issues such as failure, higher resistance, decreased efficiency and voltage spikes.
This is the reason why a group was formed to create a innovative power module — which is a system designed to house cooling electronics, power components, devices and connect them to other circuits — and with enhanced capability for managing thermal and also performance. Brice McPherson, the lead engineer, says that the aim was to develop an electrical power system that could be capable of being suitable for various applications. It was required to be compact and simple to configure and show low inductance and excellent thermal conductivity.
The image below shows the new design that is just a bit larger than the U.S. quarter.
The power pack, which shows the individual components (left) as well as the complete assembled unit (right).
Cooling Off: Harsh Environments Require Stable Materials
The team started with two materials to test the gallium nitride (GaN) and silica carbide (SiC). The benefit of these materials is that they are both broad-bandgap semiconductors that can safely be used at temperatures and frequencies that are high. They are able to be used in harsh environments where electronic components are prone to fail. For instance, it’s a bit difficult to safeguard the electronics in drill equipment in environments where temperature and pressure rapidly increase and create electronic devices that are able to withstand being shipped on the planet Venus.
McPherson employed COMSOL software to assist in their design processby studying the electrical and thermal response of the new power system in the event that it contained each of the materials selected. McPherson analyzed the thermal conduction (aiming to increase it while reducing resistance to thermal) as well as inductance and the dimensions of the device.
McPherson presented his ideas in comparison to the most commonly used transistor outline package, called the TO-254 with the intention of improving over current standards in the industry. He hoped that the new APEI model would be able to endure temperatures that are extremely high -over 225 degrees Celsius. The results of the simulation showed that both APEI power modules had an lower thermal resistance as well as significantly lower inductance than TO. Also, the results showed that they worked successfully in the temperature range specified.
Providing New Inductance and Thermal Management Capabilities
The researchers found that optimizing the dimensions of the device and the thickness of base plates were among the primary factors in the reduction of the inductance in each device. He optimized the cross-sectional size and reduced the flow path of current in order to reduce inductance while maximizing the dissipation of heat. Its COMSOL Multiphysics results showed that GaN had one of the lower inductances (7.5 nanohenries). The SiC proved to be the most suitable option for situations where large temperatures and currents were present, as well as processing huge quantities of energy within an extremely small space.