Study On Inductive Charging Experiment System

Inductive charging is an advanced new charging technology which utilizes electromagnetic induction in the coupling to provide a non-contact charge coupling to transfer power, and makes up the shortages of the traditional conductive charging. The technology is mainly applied to electric vehicles (EV), and also have great potential to be widely used in many other fields such as cableless robots, etc. The paper aimed to set up a complete inductive charging experiment system. Based on this experiment system, the paper studied on power transfer and it's control mechanism of inductive charging.The paper firstly analysed the overall design of inductive charging experiment system. The 50 Hz AC utility is rectified to DC for conversion to high frequency AC (HFAC) power. The HFAC is transformer-coupled at the coupler, then rectified and supplied to the batteries. Battery charging information is fed back to the primary side using a wireless communication link.Compared with the separable type and linear type coupler, the rotary type had the advantage of little leakage inductance and little sensitivity on relative position, etc, so chose it as the coupler type of inductive charging experiment system. The paper set up the equivalent circuit model of the rotary type coupler, and analysed that the coupler can be simplified to a magnetizing inductance and a leakage inductance in series. Based on this model, the paper analysed the influence of magnetizing inductance and leakage inductance on inductive charging system, then designed the coupler of inductive charging experiment system.The paper designed and realized 500w series-resonant power converter for inductive charging experiment system by using the leakage inductance as resonant component. The power converter achieved the function of currentcontrol by PFM, with it's modulation range of 20kHz~100kHz. With MOSFETS soft-switched, the switching power loss of MOSFETS, the ohmic loss and the iron loss of coupler core was reduced. It had large importance to improve the whole efficiency for the system. The feed-back controller for inductive charging experiment system was designed and realized based on 80C196MC MCU. The PFM control and the function of protection of series-resonant power converter was achieved by feed-back controller, and battery charging information was fed back to the primary side by using JOV-3 radio-frequency data transfer module with the date rate of 4800 bps.Based on all the work upwards, the inductive charging experiment system was set up. Correlative experiment, including system performance experiment, coupler air gap experiment and battery inductive charging experiment was did on the system. The result of experiments was analysed and a series of conclusion was achieved. The first is that series-resonant power converter had excellent current PFM performance. The second is that coupler air gap had important influence on power transfer efficiency and magnetizing inductance. The next is that the coupler power transfer efficiency of 74.4% can be achieved. The last is that the inductive charging experiment system can charge 12V/18AH Ni-MH battery.The setting up of inductive charging experiment system and correlative experiment analysis made good foundation for deeper research work.