System-In-Package components support custom control designs for high power electronics
Equipment designed for the management of electric power grid infrastructure is increasingly critical to meeting the need for clean and reliable electric power. High power electronics at the level of multi-megawatt switching, generation and load balancing, storage, motor drives, and other distribution management demand sophisticated computing power in their embedded control systems. Because of these complex requirements and the low quantity manufacturing typical of large and high cost systems, designers have resorted to fitting existing commercial off-the-shelf (COTS) industrial subsystems to the task. This “rack-and-stack” approach has dominated control designs for high power electronics for some time, despite persistent limitations to size, reliability, and long term product support. While custom control designs might be technically superior, allowing highly tailored features and compact integration, they also come with a reputation for prohibitive engineering and manufacturing costs and schedules. Fortunately, now it is becoming possible to design control electronics using sophisticated system-in-package (SIP) and system-on-chip (SOC) components to achieve custom results within a manageable design project.
The InnovaTM SCM21001 system-on-module (SOM) from Silicon Power Corporation was designed as an embedded computing platform specifically for electric grid automation applications. A dual core Texas Instruments digital signal processor (DSP) and a directly connected Intel field programmable gate array (FPGA) are assembled as an independent real time processor subsystem, allowing both traditional DSP software and highly parallel hardware based computation and connectivity. Also on the SOM circuit board, an Octavo Systems OSD3358 embedded Linux computer SIP supports management of the real time processor and provides modern communication protocols for connection to external systems, all using readily available open source software. The SOM serves as a control system component, allowing tight integration of application specific components such as power, analog sensor conversion, and actuator drives. A conduction cooled form factor supports deeply embedded, high reliability applications. Separation of the real time functions from the Linux computer reduces or eliminates the need for specialized real time operating systems. Applying a widely understood Linux platform reduces the development burden and improves the application focus of the software team.
The initial design of the SOM was an exceptional success. Available development platforms for the OSD3358 allowed software development to begin before a SOM was available. The ease of design with the SIP produced rapid results, with the sophisticated features of the SOM all fully functional in the first prototype. Software development and system hardware design transitioned to the SOM directly, with no disruption to workflow. In the first application, a bank of thirty-two (32) simultaneously sampled 16-bit analog-to-digital converter channels was fit directly under the SOM, with outstanding benefits to solution size and performance.
This design approach enabled form factor and performance options that would be impossible with a rack-and-stack solution. The Octavo Systems OSD3358 SIP takes the work out of many of the details that previously limited the option to pursue a custom design, while also improving the overall size advantage in a meaningful way. As a component or as a reference design, the SOM demonstrates that custom control designs are again a practical and cost effective option for high power electronics.