POWER TRANSMISSION CONTROL DEVICE, POWER TRANSMITTING DEVICE, POWER RECEIVING DEVICE, NON-CONTACT POWER TRANSMISSION SYSTEM, ELECTRONIC INSTRUMENT, SECONDARY COIL POSITION DETECTION METHOD, AND PRIMARY COIL POSITIONING METHOD

• US 20090079269A1
• Filed: 09/23/2008
• Published: 03/26/2009
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Chamiraux Management LLC
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: JIN, Mikimoto
• Granted Patent: US 7,880,338 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 50/70 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, a calculation circuit that calculates the position of a secondary coil by performing given calculations, and an actuator control circuit that controls the operation of an actuator, the actuator moving the position of the primary coil in an XY plane, the actuator control circuit scanning the primary coil for detecting the position of the secondary coil L2, the calculation circuit performing the given calculations based on data acquired by the scan for detecting the position of the secondary coil L2 to determine the position of the secondary coil L2, and the actuator control circuit moving the primary coil L1 so that the position of the primary coil coincides with the calculated position of the secondary coil.

Claims

1. A power transmission control device that controls power transmission of 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 to the power receiving device;

a calculation circuit that calculates the position of the secondary coil by performing given calculations; and

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

the actuator control circuit scanning the primary coil to detect the position of the secondary coil;

the calculation circuit performing the given calculations based on data acquired by scanning of the primary coil to detect the position of the secondary coil to determine the position of the secondary coil; and

the actuator control circuit moving the primary coil so that the position of the primary coil coincides with the calculated position of the secondary coil.

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

the power transmission control device including a harmonic detection circuit that detects a harmonic signal of a drive frequency of the primary coil;

a resonant circuit that resonates with a harmonic of the drive frequency of the primary coil being formed when the primary coil and the secondary coil are electromagnetically coupled in a state in which a center of the primary coil and a center of the secondary coil are positioned at a given distance, the harmonic detection circuit detecting a resonance peak of the harmonic of the drive frequency of the primary coil due to the resonance of the resonant circuit; and

the calculation circuit performing the given calculations based on coordinate position data when the resonance peak of the harmonic has been obtained from the harmonic detection circuit to calculate the position of the center of the secondary coil.

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

the primary coil and the secondary coil being circular coils;

the actuator control circuit driving the actuator to move the primary coil along a first axis that intersects the secondary coil to perform a first scan to detect the position of the secondary coil;

the calculation circuit calculating the coordinates of a midpoint of a line segment that connects two points at which the peak of a detection signal of the harmonic detection circuit is obtained during the first scan;

the actuator control circuit driving the actuator to move the primary coil along a second axis that perpendicularly intersects the first axis and passes through the midpoint calculated during the first scan to perform a second scan to detect the position of the secondary coil;

the calculation circuit calculating the coordinates of the midpoint of the line segment that connects two points at which the peak of the detection signal of the harmonic detection circuit is obtained during the second scan; and

the actuator control circuit driving the actuator to move the primary coil so that the position of the center of the primary coil coincides with the position of the midpoint calculated during the second scan.

4. The power transmission control device as defined in claim 2, further comprising:

a capacitor connected to the secondary coil,

a capacitance of the capacitor being set so that a resonant circuit that resonates with the harmonic of the drive frequency of the primary coil is formed by the capacitor and a leakage inductance when the center of the primary coil and the center of the secondary coil are positioned at a given distance, and the harmonic detection circuit detecting the resonance peak of the harmonic of the drive frequency of the primary coil due to the resonance of the resonant circuit,

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

an approach detection circuit that generates an approach detection signal based on a coil end voltage or a coil current of the primary coil, the approach detection signal indicating that the secondary coil has approached the primary coil,

the actuator control circuit performing a scan for detecting the position of the secondary coil when an approach of the secondary coil has been detected based on the approach detection signal.

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

the secondary coil being a secondary coil provided with a magnetic material;

and

when the inductance of the primary coil has increased due to the approach of the secondary coil provided with the magnetic material and the coil end voltage or the coil current when driving the primary coil at a given frequency has decreased so that the approach detection signal has reached a given threshold value, the actuator control circuit performing the scanning to detect the position of the secondary coil.

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

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

8. A power transmitting device comprising;

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

a primary coil.

11. A non-contact power transmission system comprising:

the power transmitting device as defined in claim 8; and

a power receiving device comprising;

a secondary coil; and

a capacitor connected to the secondary coil,

a capacitance of the capacitor being set so that a resonant circuit that resonates with a harmonic of a drive frequency of a primary coil is formed by the capacitor and a leakage inductance when a center of the primary coil and a center of the secondary coil are positioned at a given distance R (R>

0).

9. A power receiving device comprising:

a secondary coil; and

a capacitor connected to the secondary coil,

a capacitance of the capacitor being set so that a resonant circuit that resonates with a harmonic of a drive frequency of a primary coil is formed by the capacitor and a leakage inductance when a center of the primary coil and a center of the secondary coil are positioned at a given distance R (R≧

0).

10. The power receiving device as defined in claim 9,

the secondary coil being a secondary coil provided with a magnetic material, and, when the distance between the center of the primary coil and the center of the secondary coil when a power transmitting device detects that the secondary coil provided with the magnetic material has approached the primary coil is referred to as L, the given distance R satisfying the relationship 0≦

R<

L.

12. An electronic instrument comprising the power receiving device as defined in claim 9.

13. A secondary coil position detection method for a non-contact power transmission system that transmits power from a power transmitting device to a power receiving device via non-contact power transmission through a circular primary coil and a circular 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 frequency of the primary coil being formed by the capacitor and a leakage inductance when the primary coil and the secondary coil are electromagnetically coupled in a state in which a center of the primary coil and a center of the secondary coil are positioned at a given distance, the method comprising:

moving the primary coil along a first axis that intersects the secondary coil to perform a first scan to detect the position of the secondary coil;

calculating coordinates of a midpoint of a line segment that connects two points at which the peak of a detection signal of a harmonic detection circuit is obtained during the first scan;

moving the primary coil along a second axis that perpendicularly intersects the first axis and passes through the midpoint calculated during the first scan to perform a second scan to detect the position of the secondary coil; and

calculating coordinates of a midpoint of a line segment that connects two points at which the peak of the detection signal of the harmonic detection circuit is obtained during the second scan to detect the position of the secondary coil.

14. A primary coil positioning method comprising:

moving a primary coil to the position of a secondary coil detected by the secondary coil position detection method as defined in claim 13 to position the primary coil to a position of the secondary coil.

15. The primary coil positioning method as defined in claim 14, further comprising:

intermittently driving the primary coil at a given frequency in order to detect an approach of the secondary coil provided with a magnetic material before performing the secondary coil position detection method,

the primary coil positioning method being performed on condition that an inductance of the primary coil has increased due to the approach of the secondary coil provided with the magnetic material and a coil end voltage or a coil current when driving the primary coil at the given frequency has decreased so that an approach detection signal generated based on the coil end voltage or the coil current has reached a given threshold value.