Power transmission control device, power transmitting device, non-contact power transmission system, and secondary coil positioning method

• US 8,310,107 B2
• Filed: 09/25/2008
• Issued: 11/13/2012
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Chamiraux Management LLC
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Jin, Mikimoto
• Primary Examiner(s): Wallis, Michael Rutland
• Application Number:
  US12/237,450
• Publication Number:
  US 20090079271A1
• Time in Patent Office: 1,510 Days
• Field of Search: 307/104, 320/108
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source

Abstract

A power transmission control device used for a non-contact power transmission system includes a power-transmitting-side control circuit that controls power transmission to a power receiving device, and a harmonic detection circuit that detects a harmonic signal of a drive frequency of a primary coil. A resonant circuit (leakage inductance and resonant capacitor) that resonates with the harmonic of the drive frequency of the primary coil L1 is formed in the power receiving device so that harmonic resonance occurs. The harmonic detection circuit detects the harmonic resonance peak of the drive frequency of the primary coil.

Claims

1. A power transmission control device that controls a power transmitting device of a non-contact power transmission system, the non-contact power transmission system transmitting power from the power transmitting device to a power receiving device via non-contact power transmission through a primary coil and a secondary coil that are electromagnetically coupled, the power transmission control device comprising:

a power-transmitting-side control circuit that controls power transmission of the power transmitting device to the power receiving device; and

a harmonic detection circuit that detects a harmonic of a drive signal of the primary coil,

a resonant circuit being formed when the primary coil and the secondary coil are electromagnetically coupled in a state in which the primary coil and the secondary coil have a given positional relationship, the resonant circuit resonating with the harmonic of the drive signal of the primary coil;

the harmonic detection circuit detecting the harmonic of the drive signal of the primary coil that occurs due to resonance of the resonant circuit; and

the power-transmitting-side control circuit detecting that the primary coil and the secondary coil have the given positional relationship based on a detection result of the harmonic detection circuit.

2. The power transmission control device as defined in claim 1,

the resonant circuit being formed by a leakage inductance and a capacitor connected to the secondary coil when the primary coil and the secondary coil are electromagnetically coupled in a state in which a position of the primary coil coincides with a position of the secondary coil in a plan view, the resonant circuit resonating with the harmonic of the drive signal of the primary coil;

and

the harmonic detection circuit operating as a position detection circuit that detects that the position of the primary coil coincides with the position of the secondary coil in the plan view.

3. The power transmission control device as defined in claim 1,

the resonant circuit being formed by a leakage inductance and a capacitor connected to the secondary coil when the primary coil and the secondary coil are electromagnetically coupled in a state in which the center of the primary coil and the center of the secondary coil are positioned at a given distance, the resonant circuit resonating with the harmonic of the drive signal of the primary coil;

and

the harmonic detection circuit operating as a position detection circuit that detects that the primary coil and the secondary coil are positioned at the given distance.

4. The power transmission control device as defined in claim 1, further comprising:

an actuator control circuit that controls the operation of an actuator, the actuator moving a position of the primary coil in an XY plane,

the primary coil being moved by causing the actuator control circuit to drive the actuator using a detection output from the harmonic detection circuit as an index to position the primary coil with the secondary coil.

5. The power transmission control device as defined in claim 1, further comprising:

an approach detection circuit that detects the approach of the secondary coil based on a coil end voltage or a coil current of the primary coil.

6. The power transmission control device as defined in claim 5,

the secondary coil being a secondary coil provided with a magnetic material, and

the approach detection circuit detecting the approach of the secondary coil by detecting a decrease of the coil end voltage or the coil current when driving the primary coil at a given frequency, the decrease being caused by an increase of inductance of the primary coil with the approach of the secondary coil provided with the magnetic material.

7. The power transmission control device as defined in claim 5,

the power-transmitting-side control circuit intermittently driving the primary coil at a given frequency in order to detect the approach of the secondary coil.

8. The power transmission control device as defined in claim 1, further comprising:

a notification section that indicates a detection result of the relative positional relationship between the primary coil and the secondary coil based on a detection output from the harmonic detection circuit.

9. A power transmitting device comprising:

the power transmission control device as defined in claim 1; and

a primary coil.

10. A non-contact power transmission system comprising:

the power transmitting device as defined in claim 9; and

a power receiving device that includes a resonant circuit, the resonant circuit resonating with a harmonic of the drive signal of a primary coil.

11. A secondary coil positioning method for a non-contact power transmission system that transmits power from a power transmitting device having a primary coil to a power receiving device having a secondary coil via non-contact power transmission through the primary coil and the secondary coil that are electromagnetically coupled, a capacitor being connected to the secondary coil, and a resonant circuit that resonates with a harmonic of a drive signal of the primary coil being formed by a leakage inductance and the capacitor when the primary coil and the secondary coil are electromagnetically coupled in a state in which a position of the primary coil coincides with a position of the secondary coil in a plan view, the method comprising:

providing a harmonic detection circuit and a notification section in the power transmitting device, the harmonic detection circuit detecting the harmonic of the drive signal of the primary coil that occurs due to resonance of the resonant circuit; and

the notification section indicating a detection result for the relative positional relationship between the primary coil and the secondary coil based on a detection output from the harmonic detection circuit; and

moving the position of the power receiving device using notification information from the notification section as an index to position the secondary coil with respect to the primary coil.