Digital twin technology is changing how the automotive industry designs and tests products and solutions for electromobility (e-mobility). With pressure to develop more energy-efficient batteries, and a ramp-up in charging infrastructure development, digital twins can help bring new products to market faster, without compromising on conformance to standards for performance and safety.
Emulator Versus Simulator
Digital twins have emerged as a hot technology topic, but the concept has its roots in emulation technology dating back to the early 1990s. Emulators imitate the behavior of one or more pieces of equipment, whether an integrated circuit or even an entire piece of equipment and have numerous applications. But before we look at applying emulation technologies, let’s review the differences between emulators and simulators first (see Table 1). These two terms are sometimes used interchangeably in engineering, but their definitions are quite distinct.
As an example of a device-under-test (DUT), consider a chip:
Simulation describes how the chip will perform once it is manufactured at the foundry. The goal is to ensure the chip can perform under different states of variables such as memory, registry, and current program counters.
Emulation means using a piece of hardware to simulate how a chip will function at near real-time speeds. The hardware allows the designer to speed up the simulation process above and beyond the capabilities of traditional simulation. This is very important for very high-performance chips, such as those used in power conversion across the e-mobility ecosystem.
Table 1. Differences between an emulator and a simulator
|A system that mimics the exact behavior of another system||A system able to mimic another system to a certain degree|
|Strictly abides by the parameters and rules of the emulated system||May not follow all inherent rules of the system being simulated|
|Copies the behavior of systems||Models applications and events|
|Example: Game consoles||Example: Flight simulator|
Emulation technology has come a long way since its early days, evolving into digital twins that utilize powerful hardware and software for engineers to customize test parameters and emulate different equipment and test scenarios. Let’s take a deeper dive into how digital twins are used in e-mobility development.
Digital Twins Assume the Roles of EVs and EVSEs
The number of new electric vehicle (EV) models is expected to more than double to over 130 models by 2024. For EV supply equipment (EVSE) vendors, testing charging stations against actual vehicles is not practical. Likewise, automotive makers face the challenge of ensuring their electric vehicles conform to differing charging standards around the globe. Testing their vehicles against real charging stations from all over the world is not feasible.
Charging stations are classified by levels as shown in table 2.
|Level 1 – AC Slow Charge||Level 2 – AC Moderate Charge||Level 3 – DC Fast Charge|
Table 2. Overview of typical EV charging types
Besides the differences between AC and DC electrical platforms, both electric car makers and EVSE manufacturers must contend with interoperability and conformance to regulations as they attempt to market their products worldwide (Figure 1).
In the past, engineers conducted manual testing and connected individual car models to various charging stations, each featuring different standards. In today’s fast-moving market, this test strategy is no longer feasible. This is where digital twins come in, automating the tests for different charging interfaces and checking the interoperability between each vehicle and charging station model (Figure 2).
Let’s look at two emulation setups used in today’s EV and EVSE design and test environments:
EV Charging Test
Figure 3 shows a high-power EV test system (center) with a liquid-cooled charging adapter that emulate DC charging infrastructure. The electricity for powering the emulated DC charging infrastructure comes from yet another emulator on the left. The carmaker can now emulate a variety of high-power DC charging infrastructure up to 600 A in less time it takes than connecting the car to multiple charging stations.
When testing a charging station design against different cars (Figure 4), a tester with a power supply can emulate an electric vehicle. The EV digital twin enables the engineer to configure the vehicle to the specifications of different electric cars.
Emulating High-Power Onboard Environment
In addition to EV and charging stations, better and cheaper battery cells are key to driving EV adoption. Many automakers have specialized teams working on EV energy storage and usage systems to meet these challenges.
Developing and testing new high-power EV batteries requires an intelligent battery management system (BMS). A BMS performs important safety, control, and regulation functions by monitoring parameters such as voltage, current, temperature, and state-of-charge. The BMS is also responsible for thermal management, energy management, cell balancing, and performance. Engineers face a challenging task to validate the BMS’s ability to carry out all these functionalities to specification.
A digital twin environment can help engineers stress test their BMS during development. This BMS environment emulator can replicate the EV battery cells, emulate failures such as open or short circuits, and even different cell temperatures, to test how the BMS responds to these events.
As the electric vehicle and charging infrastructure market continues to grow, digital twin applications will become an indispensable part of the product development and design validation process. Digital twins will ensure that their real-world counterparts not only meet industry conformance standards, but also achieve the overarching goal of a greener and more sustainable transport ecosystem.