Abstract: A wireless power transmitter has electromagnets and a transmitter coil mounted on a moving plate. Current in the main DC circuit is switched into the electromagnets by transistors that control the amount and direction of current through the electromagnets to control the strength and polarity of electromagnetic fields generated by the electromagnets. A controller initially drives a high gate voltage onto transistors to cause the electromagnets on the transmitter to generate a maximum attractive force with magnets on the receiver, causing the moving plate to move the transmitter coil into closer alignment with the receiver coil. A power factor is measured on both receiver and transmitter to estimate the power transfer efficiency. The controller then reduces the gate voltage by a step size and the power factors are measured again. The gate voltage continues to be adjusted to optimize the power transfer efficiency until reaching a maxima.