Contactless energy transmission for externally and hybrid excited traction drives
Contactless energy transmission for externally and hybrid excited traction drives
The research focus of the project is the substitution of slip rings in separately excited traction motors by contactless, inductive energy transmission.
Electrically excited drives can dispense with permanent magnets made of rare earths and still fulfil the high requirements in terms of efficiency and power density of traction drives for vehicles. However, their disadvantage lies in the necessary energy transfer to the rotor, which is traditionally achieved by using slip rings. These systems also take up a significant proportion of the installation space of the entire electric drive due to the service life dimensioning and are not suitable for all ambient conditions (explosion protection).
Current developments are aimed at replacing conventional sliding contacts with contactless energy transmission. The excitation power is transferred to the rotor without contact by means of two inductively coupled transformer coils on the shaft. There are various approaches to this, which differ in terms of coil topology and control.
DLR's approach is to miniaturise the transmission system by increasing the system frequency. By using the novel wide-bandgap semiconductor gallium nitride (GaN), these high frequencies can be switched with low losses and the same system power. A resonant arrangement is being pursued to further increase efficiency. The aim is to achieve a transmission power of 1 kW at an operating frequency of 1 MHz.
Our advantages
Small installation space
Highly integrated design
Increased performance through direct rotor temperature detection
The work focuses in particular on modelling the electromagnetic components, power electronics, control and design integration into the existing installation space of traction machines.
