POWER-RECEIVING DEVICE AND NON-CONTACT POWER TRANSMISSION SYSTEM USING SAME

• US 20130342026A1
• Filed: 03/09/2012
• Published: 12/26/2013
• Est. Priority Date: 03/10/2011
• Status: Abandoned Application

• Current Assignee: NEC Tokin Corporation (Yageo Corporation)
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Mishina, Koichi, Sato, Koji
• Application Number:
  US14/004,123
• Publication Number:
  US 20130342026A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02M 7/4818 with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuits
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power-receiving device in a non-contact power transmission system includes a power-receiving antenna circuit for receiving power transmitted from a power-transmitting device, a rectification circuit for rectifying power received by the power-receiving antenna circuit, a frequency-changing circuit for changing a received power frequency of the power-receiving antenna circuit, and a drive circuit for driving the frequency-changing circuit. The power-receiving antenna circuit includes two terminals, La and Lb. The frequency-changing circuit includes a circuit configuration symmetrical about the circuit center (center tap (CT)) thereof, and is connected between the terminals La and Lb. The rectification circuit is a single-phase bridge rectification circuit. A ground terminal of the rectification circuit is connected to the circuit center (center tap (CT)) of the frequency-changing circuit.

Claims

1. A power-receiving device comprising:

a power-receiving antenna circuit for receiving power transmitted from a power-transmitting device in a non-contact power transmission system;

a resonant capacitor;

a rectification circuit for rectifying the power received at the power-receiving antenna circuit;

a frequency-changing circuit for changing a power-receiving frequency of the power-receiving antenna circuit; and

a drive circuit for driving the frequency-changing circuit, wherein;

the power-receiving antenna circuit has two terminals;

the resonant capacitor is coupled between the two terminals of the power-receiving antenna circuit;

the rectification circuit is a single-phase bridge rectification circuit and includes input terminals, a ground terminal and a rectification output terminal, the input terminals being connected to the two terminals of the power-receiving antenna circuit, respectively, the rectification output terminal being for outputting a rectified direct-current voltage;

the frequency-changing circuit includes a first impedance, a second impedance and a semiconductor switch circuit, one end of the first impedance being connected to one of the terminals of the power-receiving antenna circuit, one end of the second impedance being connected to a remaining one of the terminals of the power-receiving antenna circuit, the semiconductor switch circuit being connected between another end of the first impedance and another end of the second impedance;

the semiconductor switch circuit has a circuit structure that has a center tap as a circuit center and is symmetrical with respect to the center tap;

the center tap is coupled to the ground terminal of the rectification circuit; and

the drive circuit is coupled to the rectification output terminal and turns the semiconductor switch circuit on in response to the direct-current voltage.

2. The power-receiving device as recited in claim 1, wherein the first impedance and the second impedance are capacitors which have capacitances equal to one another.

3. The power-receiving device as recited in claim 1, wherein the drive circuit causes the semiconductor switch circuit to turn on when the direct-current voltage output from the rectification output terminal reaches a predetermined value.

4. The power-receiving device as recited in claim 3, wherein:

the drive circuit comprises a Zener diode for sensing variation of the direct-current voltage; and

the predetermined value is a breakdown voltage of the Zener diode.

5. The power-receiving device as recited in claim 4, wherein an anode of the Zener diode is coupled to the semiconductor switch circuit.

6. The power-receiving device as recited in claim 4, wherein the drive circuit further comprises a drive voltage generation circuit which is coupled between an anode of the Zener diode and the semiconductor switch circuit and, when the Zener diode is broken down, generates a drive voltage for driving the semiconductor switch circuit.

7. The power-receiving device as recited in claim 6, wherein the drive voltage generation circuit exhibits hysteresis on a relation between an input and an output thereof.

8. The power-receiving device as recited in claim 6, wherein the drive voltage generation circuit supplies the semiconductor switch circuit with pulses as the drive voltage when the Zener diode is broken down.

9. The power-receiving device as recited in claim 3, wherein the drive circuit comprises a reference voltage generation circuit for generating a reference voltage and a hysteresis comparator for driving the semiconductor switch circuit in response to the rectified direct-current voltage.

10. The power-receiving device as recited in claim 1, wherein:

the semiconductor switch circuit includes at least two Nch FETs;

gates of the two FETs are electrically connected with each other;

sources of the two FETs are connected with each other; and

the center tap is derived from a connection point between the sources.

11. The power-receiving device as recited in claim 1, wherein:

the semiconductor switch circuit includes at least two npn-type bipolar transistors;

bases of the two bipolar transistors are electrically connected with each other;

emitters of the two bipolar transistors are connected with each other; and

the center tap is derived from a connection point between the emitters.

12. A non-contact power transmission system comprising:

the power-receiving device as recited in claim 1; and

a power-transmitting device.