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sts.components.contact.mr.placeholder Sebastian Webel
Mr. Sebastian Webel

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Pictures of the Future
The Magazine for Research and Innovation
 

Electric Mobility

Volvo C30 Electric: Test Drive in Sweden

From concept to finished car, Siemens developed an electric version of the Volvo C30 in just a few months.

With its concept for the new C30 Electric, Siemens is entering the field of electric vehicle drive systems. Compared to its first-generation, whose technology was not supplied by Siemens, the C30's output has increased by twenty percent and torque by ten percent.

I throw caution to the wind for a moment and floor the accelerator pedal. The motor kicks in powerfully and extremely smoothly, propelling the vehicle to 70 km/h in less than six seconds. The speedometer quickly climbs to 90 km/h. After that, caution returns. You’re not allowed to drive any faster than this here on the country roads outside Gothenburg in western Sweden. Besides, I’ve come here not to set a new speed record, but to test an electric car — the new Volvo C30 Electric, the first vehicle built by a major automaker whose complete drive system technology comes from Siemens.

Evolving Algorithm

Just like the vehicle, the engineers who developed the C30 Electric have also demonstrated their ability to get off to a quick start. The partnership between Volvo and Siemens, which was sealed in August 2011, was only a few months old when the first prototype hit the road. Normally, development of control software alone takes at least a year, since all possible driving situations must be taken into account. Things moved so quickly with the C30 Electric because Siemens used a tried and tested control system concept. “The core of this concept is an algorithm we’ve been continually developing for years,” says Malte-Michael Ewald, who is managing the project at Siemens Inside e-Car. The algorithm is also used to control industrial units, mine vehicles, and hybrid bus drive systems.

Most of the car’s hardware, which consists of an electric motor and an inverter, also includes proven Siemens components. Here, a permanently excited motor is used — a type of motor that works with permanent magnets. It has a continuous output of 89 kilowatts, which can be temporarily stepped up to 110 kilowatts. Its maximum torque is 250 newton meters. Compared to the first-generation C30 Electric drive, whose technology was not supplied by Siemens, output has increased by 20 percent and torque by 10 percent, even as the drive system’s outer dimensions have remained the same.

Compared to the first generation C30 electric drive, output has increased by 20 percent.

Still, it wasn’t as if the car’s developers could simply pull parts off a shelf and install them. Instead, they had to adapt components to ensure they would comply with the automotive industry’s stringent quality standards. In addition, the drive system is housed in the front of the vehicle — precisely the area where kinetic energy is converted into deformations in a crash. Although comparatively few units were produced, Volvo conducted its crash tests as meticulously as it would have done with a high-volume model.

The country road is empty, so it’s time for the next test. I floor the accelerator and release, over and over again. Then I accelerate with my right foot and brake with my left at the same time. Finally, I repeatedly tap the accelerator at a speed of 30 km/h. All of these moves are completely illogical; only a driver who’s distracted or panicky would make them. But nothing happens — not even a jerk, and that’s a good sign. It’s almost as if the C30 Electric is saying to me, “Go ahead, I won’t lose my cool!”

But the Volvo’s stoic calm is not a given. It’s a true art to design a drive control system that produces no surprising results, even when it’s operated in a completely haphazard manner. “In the worst case, a flawed design could destabilize the entire control system,” Ewald explains. Engineers from Volvo, who programmed the vehicle control system, worked with the Siemens development team to find a variety of solutions. One of these was to “level out” input signals. This ensures that the development and reduction of torque is always smooth, even during rapid load changes.

Tried and Tested Technology

Volvo manager Johan Konnberg, who is responsible for electric drive development, emphasizes how well the components of the onboard electronics system work together. He also praises the fact that everyone involved in the project learned from one another. “As a relatively small premium manufacturer, we need strong supplier partners,“ he says, adding that he considers the C30 Electric just the first project in a far-reaching partnership. Indeed, Volvo plans to convert its entire product portfolio over the next few years. The goal is a uniform platform that will include a Scalable Product Architecture (SPA). Thanks to SPA, the automaker will be able to offer various vehicle body types — from compacts to SUVs — at competitive prices, even in small unit volumes.

Volvo’s drive systems will be standardized across all models. As a result, the company will use three and four-cylinder diesel and gasoline engines in only a few output classes in the future. It will adopt a similar approach with its electric models, which will also be equipped with standardized systems for use in different output classes. The range of vehicles will not be limited to battery-electric cars. Volvo is currently focusing on plug-in hybrids equipped with a combustion engine and an electric drive system with a battery that is rechargeable from an electrical outlet.

The Volvo C30 Electric wasn’t originally planned as an electric vehicle or designed specifically to accommodate an electric drive system. The body was built at the Volvo plant in Ghent, Belgium, and was then shipped to Gothenburg, where the electric drive system was installed. This system includes a lithium-ion battery with a nominal capacity of 24 kilowatt-hours, which translates into a range of at least 120 kilometers in practice.

"The battery will be fully recharged by the time we get back from lunch."

“Using tried and tested automotive technology is the right strategy when you’re dealing with low unit volumes,” says Konnberg, who points out that only 100 new C30 Electric models will be built initially. Half of these will be tested in Sweden and Norway. Siemens will make the other half available for use at various facilities. All of the cars will be equipped with a data-recording device that will collect information on driving profiles. “This will provide us with important knowledge for the further development of the vehicles,” says Ewald, who will use three of the cars himself for testing purposes. The data they provide will be utilized to refine components and software. Among other things, plans call for the inverter, which still consists of typical industrial electronic components and systems, to be modified for mass vehicle production applications.

I park the C30 Electric on the outskirts of Gothenburg, in front of a hotel and right next to a Siemens charging station. Konnberg plugs it in. “The battery will be fully recharged by the time we get back from lunch,” he promises. An onboard charging device developed by Volvo enables the C30 to make full use of its 22-kilowatt charging power — the maximum an alternating current charging unit is capable of delivering. “Just ten minutes of recharging results in an additional range of 20 kilometers,” Konnberg says, beaming with pride. However, even in Sweden, people don’t eat their lunch that fast.

Johannes Winterhagen
Picture credits: all pictures Volvo; Picture gallery: picture 1,2,4,5 Volvo