Inductively coupled power transfer (ICPT) systems are widely used in monorail transportation areas. A typical ICPT system is composed of a primary track and a pickup [1]. The pickup is usually attached to a moving unit, and is designed to travel along the primary track. Majority of monorail ICPT systems are based on E-pickups [2]. However recently S-pickup was introduced due to its high power transfer ability [3]. Fig. 1 shows E-pickup and S-pickup on a single track. The S-pickup delivers twice as much power compared to E-pickup. However the magnetic coupling ratio of S-pickup is 0.83, while the magnetic coupling ratio of E-pickup is 0.75. The magnetic coupling ratio by itself does not necessary reflect the power of pickups. We propose to have a wider look at the pickups and to analyze two significant parameters. One if a field cancellation factor (FCF), and the second on is the power to volume of ferrite ratio (S/v). Field cancellation factor is computed from a finite element method model, where only one conductor of the monorail track is supplied (IA or IB) In such model a large portion of magnetic flux flows through the coil and some portion of flux misses the coil. Eventually this small portion of flux is to be cancelled it the two conductors of the monorail track are carrying the current. Fig. 2 illustrates the definition of FCF using an example of Lambda-pickup. Due to the asymmetrical structure of Lambda-pickup FCF is calculated as average value from two models, where IA=0 and IB=0 respectively.
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