Capacitor Less High Strength Resonant Wireless Power Transfer Using Open Bifilar Spiral Coil
ABSTRACT
High efficient Wireless power transfer(WPT) system is required in many applications to replace the conventional wired system. The High Temperature Superconducting(HTS) wires are examined in WPT systemto increase the power transfer efficiency (PTE) as compared with the conventional copper/Litz conductor. The HTS conductors are naturally can produce higher amount of magnetic field with high induced voltage to the receiving coil. Moreover, the WPT systems are prone to misalignment which can cause sudden variation in the induced voltage and leads to rapid damage of the resonant capacitors connected in the circuit. Hence, the protection or elimination of resonant capacitor is required to increase the longevity of WPT system, but both the adoptions will operate the system in non-resonance mode. The absence of resonance phenomena in the WPT system will drastically reduce the PTE and correspondingly the future commercialization. This paper proposes an open bifilar spiral coils based self-resonant WPT method without using resonant capacitors at both the sides. The mathematical modelling and circuit simulation of the proposed system is performed by designing the transmitter (Tx) coil using HTS wire and the receiver (Rx) with copper coil. The three dimensional modelling and Finite element simulation of the proposed system is performed to analyze the current density at different coupling distance between the coil. Further, the experimental results show the PTE of 49.8 % under critical coupling with the resonant frequency of 25 kHz.
EXISTING SYSTEM :
Wireless power transfer (WPT) is of increasing interests today. High temperature superconducting (HTS) WPT has been demonstrated to be more efficient than copper WPT. In our previous work, we found that the efficiency of WPT from a copper coil to a HTS coil is lower than the efficiency of WPT from the same HTS coil to the same copper coil. Thus, the transmitter and the receiver are asymmetric and this asymmetry degrades WPT performance. In this paper, it is demonstrated theoretically and experimentally that for WPT between a HTS coil and a copper coil: asymmetry does exist and influences properties; the root of the asymmetry is the different resistances between the HTS coil and the copper coil; the effects of the asymmetry can be eliminated by optimizing the load; the proposed theoretical calculation fits the experimental results well.
PROPOSED SYSTEM :
The modelling and analysis of capacitor less WPT system using HTS- Copper open bifilar coil is examined. The mathematical derivation for the inductance, stray capacitance of the bifilar coil and the PTE of the system is obtained. Based on the theoretical estimated parameter, the PTE of the designed system achieves 49.8% efficiency at the self-resonant frequency of 25 kHz.The proposed approach could be to improve the PTE by employing the intermediate resonators and analyzing the effects of both side bifilar coil structure. In addition, the proposed technique can be further investigated to the self-resonant capacitive WPT system.
CONCLUSION :
The modelling and analysis of capacitor less WPT system using HTS- Copper open bifilar coil is examined. The mathematical derivation for the inductance, stray capacitance of the bifilar coil and the PTE of the system is obtained. Based on the theoretical estimated parameter, the PTE of the designed system achieves 49.8% efficiency at the self-resonant frequency of 25 kHz. Further the bifilar coil model is designed using FEM software to analyze the current density at different coupling distance. The experimental investigation results performed at different range of coupling distance are close to the simulation. Hence the proposed open bifilar coil WPT system can be utilized for the high power applications without employing the resonant capacitors. The future scope of the proposed approach could be to improve the PTE by employing the intermediate resonators and analyzing the effects of both side bifilar coil structure. In addition, the proposed technique can be further investigated to the self-resonant capacitive WPT system.