A contactless recharging system (10, 100, 200, 300) and method for recharging a battery storage device (12) onboard an electric vehicle (14, 106, 302) has a primary converter station (20, 102, 202, 304) for converting power from a power source (16) into high frequency power at a selected charging rate The vehicle has a secondary converter (32, 150, 306) for converting high frequency power into DC power to charge the battery The converters are coupled together by a contactless coupling of a conductor loop (30, 104, 308, 420, 430) and a coupling link (25, 25', 110, 205, 310, 310', 310') forming a coaxial winding transformer The coupled link and loop carry a communication indicating the selected charging rate of the battery The link has a magnetic core (40; 50; 112; 318, 320, 322 and 324) and a core-mounted conductor (45; 55; 120; 326, 328, 330 and 332) at least partially surrounded by the core The core-mounted conductor selectively at least partially surrounds a portion of the loop to transfer power therebetween The core-mounted conductor is coupled to one of the converters, and the loop is coupled to the other converter

Contactless battery charging system

The ability to transfer large amounts of electrical power (up to 1 MW) to a moving load has traditionally used means that are unreliable, inefficient, and potentially unsafe. These include sliding or rolling metal contacts, sliding carbon brushes, and trailing cables. More recently, flat inductively coupled coils have been used to help mitigate these problems. Except for the inductively coupled coils, these techniques have not been developed with the capabilities of power electronics in mind. This paper presents the first conceptual description of a power delivery system design unifying power electronics and a coaxial-winding transformer for devices that require a contactless connection and/or relative motion while delivering large amounts of power. The transformer's unique characteristics and how they might be used to advantage in combination with power electronics are emphasized. Potential applications are flexible power distribution, material handling, electric vehicle boost, and battery opportunity recharge. Test results of a small scale prototype are presented and verify these initial concepts.

Contactless power delivery system for mining applications

A submersible contactless power transfer system, especially for powering underwater electric loads, including movable loads, such as underwater vehicles, elevators, or worksite equipment. A converter supplies high frequency power to a conductor loop. A coupling sheath or link has a core-mounted conductor at least partially surrounded by a magnetic core which slidably receives a portion of the conductor loop within the link. An optional secondary converter converts power from the core-mounted conductor to meet the load requirements. A contactless power distribution system is submersible to deliver power to underwater loads through clamped-on or captive links attached at any location along the conductor loop. Methods are also provided of powering loads submersed in water, including seawater, or other non-magnetic liquid mediums.

Submersible contactless power delivery system

A parallel resonant power converter (PRC-LLCC) is analyzed for automatic inductive charging applications. The tank circuit of this power converter consists of a leakage inductance, a magnetizing inductance and two power capacitors with an inductive output filter. This converter allows the transfer of power without oversizing the inverter and a soft-switching mode of the transistors. The soft-switching mode and the sensitivity to the load variation, the coupling factor and the air gap (6-8 mm) are studied using the first harmonic method. The choice of the working range and the validity limit of the analysis method are presented. Theoretical results are validated experimentally with a 3 kW prototype.

A multi-resonant converter for non-contact charging with electromagnetic coupling

A contactless power transfer system, especially for powering electric loads, hazardous loads or underwater loads and the like. A converter supplies high frequency power to a conductor loop. A coupling sheath or link has a core-mounted conductor at least partially surrounded by a magnetic core which slidably receives a portion of the conductor loop within the link. An optional secondary converter converts power from the core-mounted conductor to meet the load requirements. A contactless power distribution system delivers power to a variety of loads through clamped-on or captive links attached at any location along the conductor loop. Methods are also provided of powering a movable electric load, or a stationary load from a movable source, and of distributing power to a plurality of portable electric loads.

Contactless coaxial winding transformer power transfer system

A load side resonant, high power density, DC-to-DC converter is discussed. The proposed converter features a constant current source output characteristic while utilizing all component parasitics. The converter is based on a half-bridge topology with zero voltage switching (ZVS) characteristics, feeding an isolation transformer and output rectifiers. The converter's resonant action is based on the leakage inductance of the isolation transformer and the output rectifier capacitance. This output side resonance resets the energy normally dissipated in the Schottky capacitance and also enables a buck-boost condition for the output voltage. The converter demonstrates current source output characteristics which are applied to a battery charging application. Coaxial winding techniques for the isolation transformer are also investigated. These winding characteristics are shown to be unique and favorable when applied to DC-to-DC converters and especially the dual resonant converter topology. >

R. Mohan

Papers

A ZVS dual resonant converter for battery charging applications