Wireless Charging System Using Resonant Inductor in Class E Power Amplifier for Electronics and Sensors

Area of Science:

• Electrical Engineering
• Power Electronics
• Wireless Power Transfer

Background:

• Traditional four-coil wireless power transfer (WPT) systems often suffer from inefficiencies and increased costs due to complex impedance matching networks and separate resonant inductors.
• The use of a Class E power amplifier as a power supply in WPT systems can lead to power loss and reduced overall system efficiency.

Purpose of the Study:

• To propose a simplified and more efficient design for four-coil WPT systems.
• To reduce the cost and power loss associated with impedance matching networks and electronic components.
• To improve the output power and transfer efficiency of WPT systems.

Main Methods:

• A novel design method is proposed that integrates the resonant inductor of the Class E power amplifier with the excitation coil of the four-coil WPT system.
• This method considers various factors including output power, transfer efficiency, coil turns, and coil size.
• The design eliminates the need for a separate resonant inductor and load matching circuit, simplifying the system structure.

Main Results:

• The proposed method simplifies the WPT system structure by removing the resonant inductor and load matching circuit.
• System power loss is reduced, and efficiency is improved.
• Experimental validation demonstrated an 18.7% increase in output power and an 11% increase in efficiency.
• The system achieved a transmission distance of up to 0.7 meters.

Conclusions:

• The proposed inductor-sharing design method effectively simplifies the four-coil WPT system structure.
• This approach enhances system efficiency and output power while reducing costs and component count.
• The method offers improved system stability by eliminating the need for precise resonant inductor tuning.
• The validated design is suitable for wireless power supply applications in electronics and sensors.