Japanese breakthrough could help make a 'fully wireless society'

A research team at Chiba University, led by Professor Hiroo Sekiya, has developed a machine learning-based design method for wireless power transfer (WPT) systems that maintain stable output regardless of load changes, a property known as load-independent (LI) operation. Traditional WPT systems require precise component values based on idealized equations, but real-world factors like parasitic capacitance and manufacturing tolerances often cause unstable output voltage and loss of zero voltage switching (ZVS), which reduces efficiency. The new approach models the WPT circuit with differential equations incorporating real component behaviors and uses a genetic algorithm to optimize circuit parameters for stable voltage, high efficiency, and low harmonic distortion. Testing their method on a class-EF WPT system, the researchers achieved voltage fluctuations under 5% across varying loads, significantly better than the 18% typical in conventional systems. The system delivered 23 watts at 86.7% efficiency and maintained ZVS under different load conditions, including light loads, due to