In the growing electric vehicle charging market, why improving interoperability is important

Manufacturers of electric vehicle (EV) charging systems need to consider two factors: first, designing a charging system that can operate reliably for years to come; second, providing consumers with a smooth, good charging experience.

The Charging Interface Initiative (CharIN), an industry association with 330 member companies in many different countries, is pushing for the development of interoperability standards for all types of electric vehicles in the field of charging systems. In addition to developing the Combined Charging System (CCS) that has been adopted by EV charger manufacturers in multiple countries/regions, CharIN is also making steady progress in implementing the North American Charging Standard (NACS) used by Tesla fast charging stations in the United States. ) standardization.

Earlier this year, Brian Berner discussed her thoughts on the recent adoption of the North American Charging Standard (NACS) by many automakers with Erika Myers, executive director of CharIN North America. Myers said, "CharIN expects that the CCS standard and NACS/SAE J3400 will coexist as two EV charging options for some time. Our view is that both standards have the potential to provide a seamless user experience, which is important for satisfying consumer needs." Industry collaboration is essential to achieve consistent interoperability across the charging ecosystem, ensuring a great user experience while reducing market complexity and consumer friction. confusion and accelerate the adoption of electric vehicles.”

As the development of various standards progresses, Texas Instruments, as a member of CharIN, will continue to work with customers to simplify electric vehicle charging connections and meet interoperability needs. But the reality is that customers still need to meet many standards, and building the entire system would overwhelm even the most capable team of engineers. Learn about several of the factors that influence the design decisions of electric vehicle charging manufacturers below.

Commonly used electric vehicle charging connector types

When driving an electric car on a cross-country road trip, not being able to find a compatible charging station can result in being stranded on the side of the road, with some charging stations unable to connect while charging, and the electric car battery having a low charge. With range anxiety, drivers can quickly become stressed and frustrated. The next DC fast charging station on your journey may not be compatible with that EV, or the appropriate connector location may already be in use by someone else.

One suggested solution to this dilemma is to use NACS connectors, which use the same type of connector for AC and DC charging and have a smaller profile than other standardized connectors. Janek Metzner of Pionix said, "The domino effect (of adopting NACS) is happening faster than expected. If SAE formally standardizes the connector, it will help bring higher adoption rates." Pionix's Linux-based open source EVerest platform software The stack enables communication between Electric Vehicle Supply Equipment (EVSE) and vehicles and is compatible with our AM625 processor.

Although expressed differently, Meyers and Metzner's views are actually consistent. CharIN and Pionix were premised on the need for improved interoperability during the global transition to electric mobility. Texas Instruments develops embedded processors and analog products that help designers create applications that transition to a world that uses more renewable energy and support efficient EV charging and a more efficient, smarter grid. As long as both the charging station and the vehicle are physically compatible and communicate in the same way, the connector type basically doesn't matter. Table 1 shows the various connector types and their definitions.

Table 1 Connector types, acronyms and definitions

In electronics, a "handshake" refers to an agreement between two integrated circuits that need to work together in the same system. Handshaking can occur between two ICs on the same board, but is easier to understand if there is a cable between the two systems. Fortunately, the EV charging station and the vehicle are always connected by a relatively long cable, so inserting the cable plug into the socket and forming an electrical connection can intuitively be understood as the two systems shaking hands.

The key concept of the handshake involved in EV charging is to generate a voltage on one side and terminate it with a resistor on the other side, reducing the voltage to a specific level. Since everyone uses the same voltage and the same predefined resistor value, this handshake will always produce the same result unless something goes wrong. In the event of a fault a decision will be made to either continue with basic charging or proceed to a more in-depth negotiation called advanced charging.

While basic charging is simple from a communications perspective, the circuitry required to turn relays on or off and detect fault conditions can be very complex. The AC Level 2 Charger Platform Reference Design can be used to begin implementing many of the functional blocks in a typical EV Supply Equipment (EVSE) system. For many basic chargers, a small microcontroller such as the MSPM0G3507 may be sufficient. However, if both the charging station and the electric vehicle support advanced charging, the switch to digital communications will be agreed and an Arm-based processor running embedded Linux will almost always be required. Table 2 highlights various analog handshake options in charging systems.

Table 2 Analog handshake terms, acronyms, and definitions

Just because two people speak the same language doesn't mean they will necessarily understand each other's regional dialect, accent, or slang. The ISO 15118 standard is like a universal language for electric vehicles and charging stations, and the way specific brands use it is often like slang. If the charging station is not familiar with the electric vehicle brand, it is easy to misunderstand.

User experience will greatly influence whether consumers consider purchasing an electric vehicle, and using a common digital communication language across electric vehicle charging infrastructure is necessary to increase adoption. In addition to its partnership with CharIN, Texas Instruments has partnered with Pionix to provide customers with Pionix's open source EV charging software stack, designed to address the most complex challenges facing the electric vehicle charging industry today: providing fully tested and standards-compliant digital communications, and Compatible with almost all electric vehicles on the market. Table 3 lists the various digital communication options associated with electric vehicle charging systems.

Table 3 Digital communications terms, acronyms and definitions

Texas Instruments' AM625-based EVSE development platform is designed to demonstrate and support all standards-compliant digital communications, demonstrating the scalability of the AM625 processor family in electric vehicle charging applications.

While universal connectors have the potential to simplify the EV charging experience, providing adapters and installing different types of plugs in charging stations can address compatibility issues with physical connectors. Analog handshaking is the underlying rationale. Creating an easy-to-use, standardized charging infrastructure requires each charging station to speak the same language and dialect as all connected electric vehicles. As a semiconductor manufacturer, Texas Instruments shares the same goal as its electric vehicle charging manufacturer customers around the world: to continue designing and developing technology that solves interoperability issues and ultimately provides a smooth charging experience for all electric vehicle drivers.

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