Power balance of inductive wireless power transmission

The analysis of power balance for concepts of wireless power transmission based on electromagnetic induction is performed in general way. The derivation of power transmission efficiency is shown. The conditions for maximal efficiency and maximal active power delivered to the appliance are found. The maximal efficiency is expressed as a function of single variable. The power balance for maximal efficiency and maximal active power delivered to the appliance is derived in terms of normalized active powers as functions of the same variable as maximal efficiency. The system input impedance is calculated.