METHOD AND APPARATUS FOR CONTACTLESS POWER TRANSFER

• US 20110080056A1
• Filed: 06/08/2009
• Published: 04/07/2011
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Chinga, Raul Andres, Low, Zhen Ning, Lin, Jenshan
• Granted Patent: US 8,674,551 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits

Abstract

Embodiments of the subject invention pertain to a method and apparatus for contactless power transfer. A specific embodiment relates to an impedance transformation network, a new class of load network for application to a contactless power system. Embodiments of the impedance transformation network enable a contactless power system to operate without encountering the common problems of: 1) over-voltage and/or under-voltage conditions; 2) over-power and/or under-power conditions; 3) power oscillations; and 4) high heat dissipation.

Claims

1-110. -110. (canceled)

111. An apparatus for wireless power transfer, comprising:

a rectifier stage, wherein the rectifier stage is adapted to interconnect with a load;

a secondary coil, wherein the secondary coil is interconnected with the rectifier stage;

a primary coil, wherein the primary coil is coupled to the secondary coil;

a tuned switch-mode supply, wherein the tuned switch-mode supply is interconnected to the primary coil;

a power supply, wherein the power supply supplies power to the tuned switch-mode supply;

a first circuitry interconnected between the tuned switch-mode supply and the primary coil; and

a second circuitry interconnected between the secondary coil and the rectifier stage, wherein power output to the load is adjusted as the phase angle of the load changes.

112. A circuit for inductive power transfer, comprising:

an impedance transformation network, comprising;

an input port configured to couple to an active device that creates a signal at a selected operating frequency, the impedance transformation network having an input impedance looking into the impedance transformation network through the input port,

an output port configured to couple to a load having a variable impedance; and

a reactive network coupled between the input port and the output port, wherein the reactive network comprises;

a primary coil; and

a secondary coil inductively coupled to the primary coil;

wherein, when the output port is coupled to the load and the input port is coupled to the active device, a phase angle of the input impedance is correlated with the amount of power delivered to the load.

113. The circuit according to claim 112, wherein the phase angle is inductive and negatively correlated with the amount of power delivered to the load.

114. The circuit according to claim 112, wherein the phase angle is capacitive and positively correlated with the amount of power delivered to the load.

115. The circuit according to claim 112, wherein the phase angle is positively correlated with the resistance of the load.

116. The circuit according to claim 112, wherein the reactive network further comprises at least one shunt network with a negative reactance that is connected between a first terminal of the secondary coil and a second terminal of the secondary coil.

117. The circuit according to claim 116, wherein the at least one shunt network with a negative reactance comprises a capacitor.

118. The circuit according to claim 112, wherein the active device comprises a transistor.

119. The circuit according to claim 112, wherein the active device comprises an inverter.

120. The circuit according to claim 112, wherein the phase angle is within a range such that substantially zero voltage switching of the active device occurs.

121. The circuit according to claim 112, wherein the phase angle is within a range such that substantially zero voltage derivative switching of the active device occurs.

122. The circuit according to claim 112, wherein a rectifier is positioned between the impedance transformation network and the load.

123. The circuit according to claim 122, wherein the load comprises a portable electronic device.

124. The circuit according to claim 112, wherein the primary coil is a single primary coil inductively coupled to at least two secondary coils.

125. The circuit according to claim 112, wherein the at least two primary coils are inductively coupled to the secondary coils.

126. A circuit for inductive power transfer, comprising:

a primary impedance transformation network, comprising;

an input port configured to couple to an active device that creates a signal at a selected operating frequency, the primary impedance transformation network having an input impedance looking into the primary impedance transformation network through the input port,

a primary coil configured to couple to a secondary coil; and

a reactive network coupled to the input port and coupled to the primary coil, wherein the reactive network comprises;

at least one capacitor; and

at least one inductor;

wherein when the primary coil is coupled to the secondary coil and the input port is coupled to the active device, a phase angle of the input impedance is correlated with the amount of power inductively transferred from the primary coil.

127. The circuit according to claim 126, wherein the phase angle is inductive and negatively correlated with the amount of power inductively transferred from the primary coil.

128. The circuit according to claim 126, wherein the phase angle is capacitive and positively correlated with the amount of power inductively transferred from the primary coil.

129. The circuit according to claim 126, wherein the reactive network further comprises at least one additional shunt network connected between a first terminal of the primary coil and a second terminal of the primary coil.

130. The circuit according to claim 129, wherein the at least one additional shunt network has a positive reactive value such that the phase angle looking into the impedance transformation network through the input port is positively correlated with the load resistance.