Due to the physical properties of electrons and materials, all electronics can only function properly given a certain set of conditions. If those conditions are not met, then the system fails. Power electronics (PE) are the systems and devices used to preserve the operating conditions for each component of the electronic system to ensure that the overall system continues to function. To accomplish this, PE systems transform the voltage, current, frequency, and power from one form to another to ensure that the operating conditions at each point in the circuit allow for the desired functionality.
The power levels for PE applications range from orders of magnitude in volts in smartphones all the way to megavolts in utility scale energy storage and grid distribution. The global market for PE is expected to double over the next five years, and the global regulatory focus on increased efficiency and integration of renewables is hastening the need for innovation in PE technology to help reduce costs and losses during the transformation performed by PE.
To better understand where this industry is heading, it is useful to understand all the pieces and steps to make a power electronics device, and some of the trends in each of these spaces. Figure 1 below shows the broad power electronics manufacturing process.
Figure 1: Power Electronics Manufacturing Process
Wafer Production is the heart of a power electronics system. The power semiconductor allows for switching power flow based on an input signal. By enabling a change in power flow, it is the basis by which power is controlled and directed, thereby allowing for complex power conversion processes based on varying the input signal and the circuit it is placed in. The power semiconductor consists of an integrated circuit (die) mounted on a substrate wafer. Traditionally, the substrate is a high purity silicon crystal that is specifically grown to exhibit desired properties, then sliced and polished into wafers. Additional layers are added using the epitaxy process. At this point, the wafer is ready for the die to be mounted.
On each wafer, integrated circuits are mounted through various processes that often consist of hundreds of steps. The primary challenge during this stage is to ensure that no contaminants or defects enter the device, requiring strict testing and quality control processes. Each wafer can hold hundreds of dies. Therefore, after the integrated circuits are created, the wafer is diced into the individual dies. Once the die is diced, the power semiconductor is ready to be packaged.
Packaging is the process of making the connections needed so that it can be connected to the outside circuit as desired. The process here involves adding bonding and connections, while making sure that the thermal and electric environment is suitable for the device to function properly.
Once the device is packaged, the next step is to assemble the rest of the PE circuit. The PE circuit is engineered and designed to perform a desired transformation on the power, to yield the desired output. The design and engineering of these circuits requires deep electrical engineering knowledge. Implementing these circuits requires sourcing all of the necessary components in the circuit (resistors,capacitors, etc), integrating them onto a circuit board to which the power semiconductor device connects, and depending on the application, adding structural and thermal supports to achieve the desired functionality.
Finally, after the PE circuit is created, it is integrated into the final product as determined by the end application. The application specifications and requirements drive the application engineering and design activity around how this integration occurs each of these processes has its own trends and market drivers shaping the technology within each stage. Some of these include the adoption of wide-bandgap semiconductors, innovation in thermal management, and integration of power electronics with other systems in the final application.
For further insights into this market, be sure to join NextEnergy and the Power Electronics Industry Collaborative (PEIC) at the Power Electronics Industry Summit alongside the Applied Power Electronics Conference (APEC) in Charlotte, NC on March 17, 2015.