Case Study: Embedding Variscite System on Modules in Electric Vehicle Charging Stations

Project Overview

A US-based company specializing in EVSE (Electric Vehicle Supply Equipment) development and marketing contacted Variscite after deploying its first-generation EVSE and beginning development of a new, more advanced version. The company manufactures EVSE products in Asia for commercial and private clients, the majority being installed in office building parking lots.

While the company’s first-generation EVSE product targeted commercial customers, such as charging stations in office parking lots, their second-generation EVSE was intended for private client sales. This required production at a reduced cost. Initially, the company planned to base the second-generation EVSE on the first-generation EVSE, but soon encountered several critical challenges.

Key Design Requirements for Second-Generation EVSE

The following features were prioritized in designing the company’s new, more advanced yet more affordable, second-generation EVSE product:

• Multiple integrated interfaces and connectivity options, for full support of power management, charging measurements, fault and alert systems, cost calculation, and user interface.
• Cost optimization, to make the product affordable for non-commercial customers.
• Industrial grade temperature rating (-40 to +85°C), suitable for outdoor deployment.
• Support for OTA (over-the-air) updates, to facilitate ongoing software security and adaptability.
• Support for multiple configurations, enabling the new charging station design to satisfy a range of installation requirements.
• Quick time-to-market, requiring rapid development methodologies.

Key Development Challenges

• The market for both hybrid and electric vehicles has gained significant momentum in recent years, leading to increased demand for related products and services and considerable pressure to rapidly release a second-generation product capable of targeting consumer environments.
• An EVSE is a premium, expensive product due to the need to integrate multiple functionalities and components. Consequently, delays in development would directly impact revenue generation, increasing the risk of project cancellation.
• The project began during a period when the tech market hadn’t fully recovered from recent global electronic component shortages, limiting access to high-value silicon components like SoCs.
• EVSE exposure to rough weather conditions required all components to be rated for industrial temperature range operation (-40°C to +85°C).
• The company planned to offer multiple product variants with a few differences in specs, including Ethernet connectivity for installation in commercial building parking lots and Wi-Fi capabilities for deployment in private homes. This necessitated two different designs, extending development time and cost.

System on Module Solution for EVSE

Although the company initially began working on a “chip-down” board design rather than a System on Module (SoM) approach, the development team soon realized that many critical components were unavailable for purchase in smaller quantities. Lacking access to the latest technology, the company investigated alternatives, including the feasibility of switching to an “off-the-shelf” solution.

“We knew there was potential for a faster launch, but we had concerns about using off-the-shelf solutions”, explained the company’s VP of R&D. “First, our engineers had no previous experience designing products using a SoM approach, so we didn’t know what difficulties we might encounter along the way. On the other hand, with a purely chip-down design we knew what to expect. Second, since we had fully customized our initial EVSE design to meet our functional specs, we worried that we might need to compromise the capabilities of our next-generation EVSE’s design due to limitations imposed by integrating an off-the-shelf SoM”.

“Through a consultation with Variscite’s engineers to determine the requirements of a SoM for use as the core of the new EVSE design, we determined that a SoM-based approach could work well from both component availability and product functionality perspectives,” added the VP R&D.

VAR-SOM-6UL: The Chosen Solution

The chosen SoM was Variscite’s VAR-SOM-6UL System on Module, based on NXP’s i.MX 6UL SoC with 256MB RAM and 256MB NAND memories.

The VAR-SOM-6UL provides:

• Industrial-grade temperature operation (-40°C to +85°C).
• Comprehensive connectivity support for Ethernet and Wi-Fi requirements.
• Cost optimization suitable for consumer market pricing.
• Embedded control application compatibility ideal for EVSE requirements.

Using the VAR-SOM-6UL’s wide range of configuration options, the company created two different configurations: one compatible with the commercial office variant’s requirements, and another for private home installation needs. Both variants share the same software and a common carrier board design, with only minor adaptations.

Design Scalability and Future-Proofing

Another benefit of basing the new EVSE’s design on the VAR-SOM-6UL is the SoM’s pin-compatible design with other modules in Variscite’s “VAR-SOM Pin2Pin” product family. This enables migration to alternate Variscite Pin2Pin SoMs for future upgrades or lifecycle extension.

“Thinking about the future, we decided to design with a pin-compatible SoM to provide flexibility for developing additional variants and future generations without modifying the base hardware design and embedded software,” noted the company’s VP of R&D.

Results and Project Impact

The transition to SoM-based architecture streamlined the project and improved development efficiency. The product development cycle was reduced by approximately 50% compared to the previous generation.

“Switching to a SoM-based architecture was relatively straightforward, thanks to Variscite’s exceptional technical support,” said the VP of R&D. “The shortened development cycle exceeded our expectations, and when we faced complex technical challenges, such as implementing secure boot and secure OTA software updates, Variscite’s support team demonstrated expertise and provided effective and rapid solutions that kept our project on track.”