Electric Vehicle Technology: Drive types in electric cars
Using externally excited synchronous motors in electric cars, such as ZF had already presented in a prototype in 2012, could play a certain role in the future, especially by renouncing the controversial rare earths.
In the case of permanent-excited electro-motors, this is achieved by means of strong magnets, for which the neodymium, which belongs to the rare earths, is required. Since the supply situation (almost exclusively from China) as well as the very polluting degradation of the rare earth is strongly criticized, there is corresponding interest in foreign-controlled motors.
A further distinguishing feature of electric cars can be their drive system. Here, the front drive with a power dissipation directly from the output of the electric machine, which is established as a quasi-standard for passenger cars, is now available in the main vehicle, and the use of two motors (one per axle) is also possible for all-wheel drives. In doing so, the two electric motors do not necessarily have to be identically powerful, because all driving scenarios can be mapped using a corresponding intelligent control system. A good example of this are the all-wheel drive systems of the hybrid electric vehicles from Toyota and Lexus, where the rear-axle electric motor is rather designed as an auxiliary drive for traction improvement.
Another variant of electric car is the use of wheel hub motors which promise a maximally exact control of the driving force per wheel and thus corresponding driving dynamics advantages. Their disadvantage is, on the one hand, the high unsprung masses per wheel, on the other hand in their unprotected placement directly in the dirt area of the wheels, which requires a correspondingly complex encapsulation.
Finally, it can be said that the electromobility is in the starting holes, is indisputable. Where the path leads, the price development mainly determines the electricity storage. At least in the medium term, electric cars are likely to result in a side-by-side relationship. For commercial and private long-distance transport in the form of combustion engines and hybrid systems with power generation by gasoline engines or fuel cells. In the commercial vehicle sector still with diesel, possibly also with hybrids gas turbine.
In the short and medium-range use of the ever-growing conurbations, on the other hand, the signs are entirely based on electricity. Car sharing will play an important role in case of electric cars, in the future. However, the development of the charging infrastructure will also be crucial in the urban area. It would be possible to install electric car charging terminals, for example, on light masts, as well as contactless induction charging technology is a field where intensive research is being carried out.