Screw it in and drive Siemens saves weight and space with integrated motor and inverter By Joey Stetter
mong the companies pushing the boundaries of packaging efficiency is the German engineering colossus Siemens. The company has developed an integrated motor and inverter contained in a single housing, the Siemens Sivetec MSA 3300. The new drive unit reduces weight, frees up six to seven liters of additional space, lowers costs, and requires fewer assembly steps during vehicle production. They key goals in any automotive project are to achieve the right performance, high quality and low prices in something that can be easily integrated into new cars. “We wanted a traction drive that was easy to integrate, especially on the rear axle of the car,” Dr. Karsten Michels, Head of Development at Siemens eCar Powertrain Systems, told Charged. The idea is to target an existing platform, such as a passenger car with a combustion engine, that an OEM is interested in making into a hybrid. A compact motor and inverter assembly could easily be added to the rear axle without many additional parts. “We have to make it easy for the OEM,” said Dr. Michels. “That’s the first big advantage of combining the motor and the inverter. To put it simply, screw it in and drive. Today, the cabling is a nightmare for OEMs, especially the thick cables needed for a traction motor.” Combining the motor and inverter completely eliminates the cables between the two, which is an advantage for both space and price. “Copper is expensive stuff,” said Dr. Michels. “Also, transferring high currents is not that easy and can bring up some issues in the field. If you simply do not have these cables between the inverter and motor, it completely eliminates the concern for an OEM. The space you need is smaller and the cost is lower. These are key advantages.”
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