Electric vehicles typically excel when it comes to making a fast get-away at traffic lights. That’s because they can develop their full torque instantly, from standstill. Less typical is an EV with the awesome performance offered by the new Jaguar I-PACE, whose electric powertrain can operate at currents of up to 650 amps.
To handle these large currents and the resulting extreme load changes, Continental developed a system solution for Jaguar Land Rover that is specifically adapted to the requirements of sporty, performance-oriented powertrains. This innovative power electronics solution, which first went into production in the Range Rover Sport Plug-in Hybrid, is designed for application across the entire future EV line-up of the two British premium brands.
The power electronics is a key component of hybrid and all-electric powertrains. It supplies power to the electric motor, while also controlling the process of energy recuperation. So in terms of function, it acts as an interface between the high-voltage battery and the electric motor. Since the battery supplies DC power, but the motor runs on three-phase AC power, the power electronics must first convert the DC power using an inverter, before supplying it at the required current and frequency to the motor. It is these two electrical parameters that control the operation of the motor.
In recuperation mode, the power electronics converts the AC current produced by the electric motor into DC current, which is then used to charge the battery. It is the power electronics which determine whether the full potential of the electric powertrain can be realized. In other words, the power electronics is key to maximizing the driving enjoyment associated with the high low-end torque and instant response that form an inherent feature of electric motors.
“In view of its key role in the electric powertrain, the power electronics is a component of major strategic importance. We have been engaged in development work in this field for a long time. Today, with the third generation of our power electronics technology, we offer solutions for vehicles in all power classes,” says Christopher Breitsameter, Head of the High Voltage Electronics Segment at Continental’s Powertrain division. “In designing the power electronics for the Jaguar I-PACE and the Range Rover Sport Plug-in Hybrid, we worked closely with Jaguar Land Rover to maximize the potential of our current-generation system, with a strong focus on sporty driving and high performance.”
Built-in success factor: microchips with double sided sintered technology
The power electronics must be capable of supplying maximum current in fractions of a second, for example when accelerating at full throttle from standstill. The special challenge for the development team was to accommodate such very high load changes while at the same time meeting the requirements expected of automotive systems in terms of long cycle life and service life. A further development goal was a high power-to-size ratio, in order to shrink space requirements to a minimum. That it was possible to achieve such an excellent combination of performance, long life and compact dimensions is largely down to the innovative IGBT (insulated gate bipolar transistor) power modules which are a key component of the inverter. Sintered bonds on both sides of the chip meet much higher demands in terms of service life, reliability and thermal tolerance than conventional solder bonds, making this a solution particularly suited to the premium segment. Continental is the first company to use this sophisticated technology in an automotive electronics application.
“Further notable features in addition to the double sided sintered technology include the use of special direct copper bonded substrates, known as DCB substrates, along with power semiconductors that have been built to order specially for Continental. The overall architecture of the power electronics, and the materials used, are optimized for maximum power and performance,” says Project Manager Alexander Reich. “The good collaboration with the Jaguar Land Rover project team, for which I should like to thank everyone involved, was crucial to the success of this project.”
Another special feature of the newly developed power electronics technology is that the same system can be used in quite different types of vehicle. For example, the power electronics in the Range Rover Sport Plug-in Hybrid and the Jaguar I-PACE are completely identical in terms of hardware – the only differences are in the software.
Further Continental innovations in the field of power electronics
Continental has long been a technology leader in the electric mobility field. Its latest innovations include a complete EV axle drive system. This highly integrated, scalable solution brings together the electric motor, transmission and power electronics in a single module. This results in both weight and efficiency advantages over comparable concepts, while having far fewer connecting parts also cuts costs. 120 kW and 150 kW versions of this electric drive system are scheduled for launch in the Chinese market in 2019.