Vehicle electrification – power electronics is the key to success

December 02, 2011 // By Klaus Backhaus
Flexible, highly efficient power electronics are a central requirement to make electromobility a success. To achieve maximum power density, electric losses and thermal resistances must be kept to a minimum, and maximum component integration is required. Klaus Backhaus of Semikron describes the technological building blocks.

One of the key technologies needed to achieve widespread acceptance for electric vehicles is the use of power electronics optimised for use in hybrid and electric vehicles. Specifically, optimisation has to be achieved with regard to the efficiency of power electronic control of motors and auxiliary devices in electric vehicles, as well as to improvements in energy efficiency made possible by the connection of stationary vehicles to smart grids, which in turn enable intelligent connection between traction batteries and the grid as well as the efficient use of regenerative sources of energy. The lack of standard interfaces among component manufacturers, however, has led to the need for the development of product platforms that can be flexibly adapted to different requirements.

For 20 years Semikron has been developing and mass-producing power electronics for use in industrial electric vehicles, meaning the company is very familiar with the specific requirements of vehicle environments: power electronics used in electric vehicles have to deliver maximum power density and reliability, while being affordable and highly efficient at the same time. The interface for connection to the master controller in the vehicle must be flexible enough to facilitate adaptation to different conditions.

To achieve maximum power density, electric losses and thermal resistances must be kept to a minimum, and maximum component integration is required. At the same time, electromagnetic radiation has to be kept to within permissible limits. Low losses in turn mean high efficiency. The possible level of product reliability is determined, on the one hand, by the power semiconductor and DC link capacitor packaging, as well as the degree of electronic component integration and, on the other hand, by the thermal shocks that occur.

One way to achieve interface flexibility is to combine programmable elements. In other words, the use of a Field Programmable Gate Array (FPGA) for time-critical functions, a Digital Signal Processor (DSP) and/or microcontroller (µC) for the implementation of the control algorithms,

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