Wireless power transfer for electric vehicles

Most of the motorised electric vehicles have a plug for direct AC or DC slow or fast charging.

The growing EV market is driving the demand for more convenient and reliable means to recharge the onboard battery.

Wireless Power Transfer (WPT) requires no physical contact between the vehicle and the charging station, therefore overcoming the inconvenience and hazards caused by traditional direct-conductive methods. 

The challenge is to replace the conductive charging method by WPT technology while maintaining a comparable power level and efficiency. The long-term goal is to dynamically power the moving vehicles on the road, AGVs on a factory floor and/or autonomous robots and forklifts in a warehouse.

This may lead to a significant size reduced battery pack and extended driving range at the same time thus addressing the main concerns of EV, namely, the high prices of batteries and range anxiety.

For the past three years, PREMO has been investing in innovative Inductive Components design applying both the 3DPower concept (for the magnetics involved in WPT) and the ALMA concept (for long-range antennae using flex-magnetic core).

A Team of Scientists from Madrid’s CSIC (Superior Council of Scientific Research) led by renowned expert in Magnetism, Mr Manuel Vazquez, PhD, Head of the Nanomagnetism and Magnetisation Processes groups, researchers of UPM (Universidad Politécnica de Madrid), Andaltec (Instituto Andaluz del Plástico) and a team of materials scientists and technologists at Premo’s Innovation Center in Malaga have developed a technology aimed at Inductive Wireless Power Transfer in the range of 90kHz. 

This technology deals with the limits of conventional ferrite cores that are both fragile and brittle and cannot be manufactured reliably in the long, large and thick formats required by this application. After three years of research and development and more than one million Euros in private and public funding, the team is announcing the first industrial solutions that overcome the limits of the technology used to this date.

The main improvement in performance of Premo’s WC-Rx-Series (secondary coils) is the magnetic core technology that provides a super high efficiency (above 95%) power transfer thanks to a carefully crafted combination and optimisation of the coil (Litz wire) with a flexible-core configuration that avoids air gaps and reduces heating areas. The result is a compact secondary coil with a high Q-factor (very low losses) and high reliability.