System Integration and Experimentation

This chapter describes experiments on multifunctional contactless grid-t- -vehicle (G2V) power flow and bidirectional outer and inner communication based on the giant magnetoresistance (GMR) effect for car parking guidance. In wireless power transfer, an inverter is used to control the G2V power flow in accordance with the zerovoltage switching method for achieving high power transmission efficiency and data transfer without using any radiofrequency devices. This inverter functions over an output power of 400–700 W and an operation frequency of 19–25 kHz. In an experiment on the power transmission quality, the total harmonic distortion in the fundamental frequency was only 23.8% of the significant harmonic frequency, including the DC, second-order, and third-order frequencies, when the output power was 700 W. The data transfer performance when using the current trimming and data attachment methods was examined to generate information quality reports. These reports included information on the lateral offset, output power, and air gap. The information quality was greater than 80% when the lateral offset was −20 to 20 mm and Δτ was 3–5 μs. This lateral offset range (40 mm) was twice the width of the magnetic tape array 3 for GMR guidance, which is sufficient for wireless power charging. When the output power was 400–700 W, and Δτ was 3–5 μs, the information quality was greater than 85%. When the air gap between two power pads was 15–30 mm, and Δτ was 3–5 μs, the information quality was greater than 80%.