Modeling and Optimization of Class-E Amplifier at Subnominal Condition in a Wireless Power Transfer System for...

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Power Electronics

Background:

• Traditional class-E amplifier models for wireless power transfer (WPT) in biomedical implants neglect crucial factors like MOSFET conduction loss and voltage stress.
• This oversight limits the achievable efficiency and reliability of WPT systems for medical devices.

Purpose of the Study:

• To propose a novel circuit model for subnominal class-E amplifiers that accounts for conduction loss and voltage stress.
• To optimize design parameters for maximum efficiency and safe voltage stress in WPT systems for biomedical implants.
• To validate the proposed model and optimization method on a WPT platform for capsule endoscopes.

Main Methods:

• Development of a novel subnominal class-E amplifier circuit model.
• Analysis of the relationship between amplifier design parameters and system characteristics.
• Derivation of design parameters for the 'optimal subnominal condition' balancing efficiency and voltage stress.
• Experimental validation on a WPT platform for capsule endoscopes.

Main Results:

• The proposed subnominal model effectively characterizes class-E amplifier performance in WPT systems.
• The 'optimal subnominal condition' yields the highest efficiency (99.3% at 0.097 duty ratio).
• At a 0.5 duty ratio, the optimized amplifier achieved 90.8% efficiency, a 15.2% improvement over the nominal condition.

Conclusions:

• The novel subnominal class-E amplifier model and optimization method enhance efficiency and reliability for WPT in biomedical implants.
• The findings provide a practical approach for designing high-performance WPT systems for medical devices.
• Experimental validation confirms the feasibility and effectiveness of the proposed optimization strategy.