Power Electronics could make Hybrid Cars Cheaper
Hybrid cars are often known as “cars of the era.” The main feature of the hybrid car is that when we start the car engine, electrical energy is used. This way it helps in keeping a tab on the tail pipe emissions. The use of automobiles is increasing in every part of the globe and so is the threat of toxic pollutants and global warming, thanks to their exhaust ingredients. But if we are using a hybrid car the decrease in the tail pipe emission will do a great service to the environment and society. After starting the engine of the hybrid car gasoline engine will take up the charge. If we want to increase the speed, gasoline is essential to attribute the pace for the drive. While waiting at the traffic signals, maneuvering your car in a heavy traffic and climbing on steep slopes, the electrical energy will be again activated. This way hybrid vehicle minimizes the use of gasoline. We should not forget breaking the notorious fuel consumer. In hybrid cars while we apply breaks it is re-channeled for the electrical battery charging, known as regenerative braking, and a separate energy for battery charging is not required.
Earlier hybrid cars were considered as rare breeds but presently we can spot more and more such vehicles on the road. But still they are not produced on commercial scale. Therefore they are costly. Not all that long ago, hybrid vehicles were still really exotic. Now, you see them more and more frequently on our roads. However, hybrid cars are not mass-produced as their production costs are still relatively high. Hanna Plesko – a researcher from ETH Zurich – has given this problem a serious thought. Currently she is doing her doctorate at Power Electronic Systems Laboratory. She is developing a new concept as part of her doctoral thesis that integrates power electronic functions and an electric motor. This combination has the ‘power’ to reduce the costs of hybrid cars.
Hollywood stars such as Leonardo DiCaprio and Cameron Diaz are doing their bit by raising awareness about clean and green vehicles. They had proudly strutted their hybrid cars and driven up to the red carpet. Researchers are doing their work on making hybrid cars available to the commoner on the street. Hanna Plesko, utilizes public transport everyday to do her research on hybrid cars and the sweet irony is that she doesn’t have her own car!
Plesko is familiar with the ground realities as she says, “It’s rumored that hybrid vehicles can improve your image, but in some cases the automobile companies have difficulties to cover their costs.” The production of hybrid drives is still very expensive and the main culprits are the electric motor and the power electronic energy management system, in which inverters and DC/DC converters play a crucial role. They eat up the major chunk of money. Plesko is dealing with these two mechanisms. She is approaching the problem applying a new concept. She is focusing on the components, i.e. the power electronics and the electric motor. They might perform several functions simultaneously. The multiple uses of the electronic parts and the motor also save volume. This will help in reducing the costs.
Combination with motor has its advantages
In traditional hybrid vehicles, batteries are utilized to provide energy to electric motor, radio, ventilation and the lights. Unlike the electrical drive system, for which a high DC voltage of 200 – 600 V has to be converted into a three-phase AC voltage, a low DC voltage of 12 V is sufficient to power a car radio. Inverters are devices which convert the direct current into an alternating current. DC/DC converters transform the power between the two batteries for the two voltage levels. Therefore we can easily conclude that converters are significant power electronic mechanisms in hybrid or electric vehicles. These days converters are situated outside the electric motors.
A research group “Future Automotive Power Electronics” headed by senior scientist Jürgen Biela, is working towards the converters. Plesko is focusing on a mechanism that integrates the inverter, the DC/DC converter and the electric motor functionally. By combining the functions of the drive and the DC/DC converter, certain electronic constituents and the motor lamination stack can be shared. If we angle it from a manufacturers’ point of view we will see that large quantities of such functionally integrated systems will be cheaper as smaller number raw materials are required. Moreover, Plesko’s design is less complex, making it easier to produce.