Choosing High-Frequency Ferrite Tiles for Wireless Power Transfer Systems

Wireless Power Transfer (WPT) technology is used to supply electrical energy from a transmitter to a receiver wirelessly. With modern developments, this technology is gaining attention for use in electric vehicle chargers, robotics, biomedical devices, etc. It offers the benefits of reliability, efficiency, flexibility & easy maintenance. This type of charging also carries a lower risk of electrical shock because of galvanic isolation.

The WPT systems use ferrite tiles as one of the ferromagnetic materials to improve magnetic coupling. This is because ferrites have characteristics, such as high-frequency, high magnetic permeability, and electrical conductivity. Hence, selecting the right quality of products is important to increase the efficiency of power supply. 

In this blog, we’re going to discuss the significance of choosing ferrites to help WPT systems work efficiently for power transmission. 

How Does Wireless Power Transfer Work?

WPT technology transfers electric power through the air gap without using wires or cables. It uses the principle of magnetic induction, which is based on Faraday’s law of induction. As per the law, if there are two magnetically coupled coils, then the AC current passing through the transmitter coil will spark a voltage in the receiver coil. 

The voltage produced can be used for charging electronic devices. Through the entire process of power transmission, there is no physical connection between the transmitter & receiver coils. The power transfer happens through the magnetic fields only.  

Role of Ferrites in Wireless Power Charging Systems

The power conversion efficiency is one reason that prevented the adoption of WPT for automotive & manufacturing industries. The conventional WPT systems have magnetic flux, which is absorbed by the metal housing and doesn’t get through the receiver. 

As a result, there is an increase in power losses & decrease in power efficiency. This leads to excessive heat which can damage the components & creates safety issues for the system operator or end user. Also, these systems release high core losses at lower operating temperatures. 

To change this, ferrites are being used in the WPT system owing to the following reasons:

• Higher charging efficiency 
• Higher operating frequency 
• Wider operating temperature 
• Suitable for high power WPT Systems

WPT Systems that have ferrites suppress the electromagnetic interference between the antenna & metal housing. The magnetic flux is kept between the transmitter & receiver coils to boost the charging efficiency. Hence, ferrites prevent the leakage of magnetic energy in the metal housing. 

In addition, these systems can also operate at room temperature with high charging efficiency. 

Precautions to take while choosing Ferrites for WPT

Ferrite is an ideal material for WPT systems because of its high permeability, frequency, efficiency and temperature. But you need to take a few precautions while using it to stay safe. 

• Mechanical Stress & Shock 

Ferrite is brittle ‌and has a low tolerance level for impact. The ferrite plate can break or crack easily if it is dropped or in case any heavy object falls on it. If this broken ferrite is used in WPT, it causes heating which might damage the co-existing circuit components. Hence, it should be handled with care to avoid mechanical stress or shock.  

• High Temperatures

Ferrite material faces thermal shock at high temperatures, which leads to breakage, cracking, or loss of its properties. Hence, its temperature fluctuations must be controlled to ensure its high performance & durability. 

• Strong Attractive Force

Larger-sized ferrite magnets have a stronger attractive force. If they are not handled with safety, it may cause jamming of fingers between the magnets, which leads to cuts, bruises, & injury. Hence, you must wear protective hand gloves while handling larger or bulky ferrite magnets. 

• Initial Permeability

The stressed state of ferrite leaves an impact on its mechanical & magnetic properties, such as AL value. Higher stress leads to lower initial permeability, hence this needs to be controlled. 

Conclusion

Cosmo Ferrites Limited is a leader in manufacturing & exporting ferrite tiles for WPT systems. We use modern production technologies to ensure high charging efficiency, low core losses, wide temperature range, and excellent thermal characteristics for our products. 

Not only this, we offer custom sizes & designs of cores to serve the unique requirements of our customers. Contact us to know more, we’d be happy to help with your requirements.