Flexibility and Scalability are Key to EV Charger Designs

As many countries rush to meet their deadlines to stop the selling of internal combustion engine (ICE) vehicles, they are currently realizing that they are not where they need to be in terms of EV infrastructure. Some potential EV buyers know that there is a lack of charging points, and are delaying their purchase, meaning EV sales have dipped in some areas, instead of the expected increase in the run-up to changeover dates. More potential purchasers are waiting for faster charging options to become widely available. For those who do make the decision, many are taking matters into their own hands and installing chargers at home. These differing needs mean that there is currently a huge demand for chargers in a wide range of specifications.

Wayne Liang, senior segment engineer, E-Mobility business at Microchip explains, “if you look at the whole market space, charger designs can be very simple, such as in a residential AC charger, where much of the technology is actually incorporated into the vehicle, or they can be very complex, for example, in a high-power commercial EV charger, which takes care of all of the power conversions and delivers that power, while performing other services that add value for the operator. The most basic residential charger might only have an MCU, security, timing and analog parts, and more complex ones could add AC metering, WiFi and Bluetooth and touchscreen. Commercial chargers usually incorporate all of the above, as well as the capability to deliver multiple power levels, work on different voltage levels for different geographical areas, provide DC metering and much more. Charger designers are looking for flexible solutions that they can scale up or down to meet the wide varying levels of requirements.”

As for more specific details on the trends, Liang adds, “We are seeing power levels increasing. Right now, Tesla is charging at 350 KW, but in Asia there are moves to 1MW charging to deliver around 300 miles of range in five minutes. To handle this, designs are moving to SiC components to improve efficiency and reliability, as well as reduce the size of the charger. In fact, the reliability of chargers is one aspect of the market that has not been talked about a lot so far. One survey that I’ve seen estimates that as many as 20% of public chargers are unavailable at any time, and consumers and operators are catching on to this and looking for reliable suppliers. Microchip has placed strong emphasis on reliability, and the reference design hardware architecture has been reviewed by Underwriters Laboratories according to UL 2231 standards.”

According to Liang, Microchip is in the perfect position to help with scalability, “Charger suppliers want to sell designs to multiple OEMs. Microchip helps that by providing solutions that can scale in the three main areas found in charger designs - connectivity, embedded and power. Having a broad range of products allows designers to scale up or scale down as needed by simply swapping out components, such as the MCU for another that has the necessary performance, or includes the desired peripherals, while keeping the same software tools.”

As well as offering a broad choice of components, Microchip also provides help for engineers to get designs to market quicker. Liang explains, “As well as our portfolio of discrete products, we also offer system-in-package (SiP) and system-on-module (SoM) solutions that eliminate design work by integrating a lot of the required circuitry. We also minimize development cost and time for designers by providing multiple single- and three-phase reference designs and production software. The software stack is modular, so they can use only the parts that they require. The stack includes everything that is required for a charger solution, including modules that assist in getting certification, such as ISO 15118 for V2G communications and the Open Charge Point Protocol (OCPP).  The Open Charge Alliance (OCA) develops and manages OCPP, which is a global standard for EV charging communication. It enhances reliability by ensuring interoperability between charging hardware and management systems, enabling smart charging, remote diagnostics, and secure operations. Our modules have also gone through RF regulatory certification in various countries, and our Bluetooth solution has been certified, giving customers even greater confidence with our reference designs. There are even modules to help implement payments for credit cards.”

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