Determining coil distance of cross-segmented IPT system for constant output voltage

Inductive Power Transfer has long been considered as an advanced traction power supply technology for Electric Rail Transits. Primary coils are often segmented to reduce resistive power loss. When switching between segments, the secondary pick-up voltage may be vulnerable to large fluctuations because of mutual inductance variation and poor timing of switching actions. In this paper, a method for designing proper distance between adjacent primary coils is introduced for steadier pick-up voltage. A switching scheme and its timing for the LCL circuits is also introduced for stable segment transitioning. FEA simulation and an experimental setup were established. Both simulation and experimental results show that the output voltage remains almost unchanging with the introduced method and validate its feasibility.