Current sourced bi-directional inductive power transfer system

Modern electronic systems and appliances are preferably powered through wireless techniques. Inductive power transfer (IPT) is an efficient technique that is suitable for supplying contactless or wireless power to numerous applications. IPT systems with the capability of bi-directional power flow are attractive for applications, such as vehicle-to-grid systems and moving equipment that require contactless charging and discharging, and regenerative energy recovery. This study presents a new bi-directional IPT technique that suppling power from one system to another, across an air-gap and through weak magnetic coupling in both directions. The proposed system employs a parallel resonant circuit together with a controlled rectifier on each side of the air-gap to facilitate bi-directional and contactless power flow. A mathematical model is presented to show that both amount and direction of the power flow can be controlled through either relative phase angle or magnitude control of the voltages generated by controlled rectifiers. The viability of the proposed bi-directional IPT concept is demonstrated with experimental evidence of a 500 W prototype bi-directional IPT system. Both experimental and simulations results are in good agreement, and indicate that the proposed IPT system is feasible and attractive for applications, where bi-directional power flow is advantageous.