JP2012130173A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resonance type power supply device for non-contact charge which can suppress decline in charge efficiency without increasing the size, when a relative position between a primary coil and a secondary coil is deviated from an appropriate position.SOLUTION: A resonance type power supply device for non-contact charge includes: a primary side resonance circuit including a primary coil to which AC power is supplied to generate a magnetic field; current detection means detecting a primary side current of the primary side resonance circuit; voltage detection means detecting a primary side voltage of the primary side resonance circuit; power factor calculation means calculating a power factor based on the primary side current and primary side voltage; and characteristic adjusting means comparing the power factor with a threshold value corresponding to target efficiency and adjusting characteristics of the primary resonance circuit to increase the power factor when the power factor is below the threshold value.

Description

  The present invention relates to a power supply device, and more particularly to a contactless power supply device used for charging a battery of an electric vehicle or the like.

  A technique for charging a battery of an electric vehicle using non-contact power transmission is known. In this technique, a secondary side resonance circuit mounted on an automobile and a primary coil of a primary side resonance circuit mounted on a power supply device are arranged close to each other in the primary side resonance circuit. A magnetic field is generated in the primary coil by supplying AC power at a resonance frequency. And the battery is charged using the electromotive force which generate | occur | produced in the secondary coil of the secondary side resonance circuit by the electromagnetic induction by the generated magnetic field.

  In this technique, when the relative positions of the primary coil and the secondary coil are deviated from the proper positions, the charging efficiency is lowered. Specifically, the charging efficiency is reduced unless the vehicle on which the secondary coil is mounted is stopped at an appropriate position and charging is performed with respect to the power supply apparatus on which the primary coil is mounted.

  Patent Document 1 describes a technique for notifying the user of the power supply device when the vehicle is not stopped at an appropriate position in the vehicle charging system. Patent Document 2 describes a technique in which a plurality of primary coils are arranged in a power supply device, and the primary coil most suitable for charging is selected and used for charging in accordance with the position of the automobile with respect to the power supply device. Yes.

JP 2010-183814 A JP 2010-183812 A

  However, in the technique of Patent Document 1 described above, when the automobile is not stopped at the proper position, the driver can be notified, but the reduction in charging efficiency is suppressed unless the user corrects the stop position of the automobile. However, in Patent Document 2 described above, although the reduction in charging efficiency when the automobile is not stopped at an appropriate position can be suppressed, the power supply apparatus may be increased in size. Such a problem is not limited to an automobile charging system, and is a problem common to resonance-type power supply devices for contactless charging.

  The main advantage of the present invention is that the relative positions of the primary coil and the secondary coil are deviated from the proper positions in the resonance-type power supply device for contactless charging without increasing the size of the power supply device. It is to provide a technology capable of suppressing a decrease in charging efficiency in the case of failure.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A power supply device that supplies power for charging a battery in a contactless manner using electromagnetic induction to a battery system including a secondary resonance circuit including a secondary coil and a battery. Because
A primary side resonance circuit including a primary coil that generates a magnetic field for supplying AC power to the battery system via the secondary coil by electromagnetic induction;
Current detection means for detecting a primary current which is a current of the primary resonance circuit;
Voltage detecting means for detecting a primary side voltage which is a voltage of the primary side resonance circuit;
Power factor calculating means for calculating a power factor based on the primary current detected by the current detecting means and the primary voltage detected by the voltage detecting means;
At least one of a series resonant capacitor adjustment circuit and an inductance adjustment circuit in the primary side resonance circuit;
An inverter circuit for supplying the AC power to the primary side resonance circuit;
The power factor calculated by the power factor calculating means is compared with a threshold value corresponding to a target efficiency, and the power factor is increased when the power factor is lower than the threshold value. A characteristic that adjusts at least one of the capacitance of the resonance capacitor adjustment circuit, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary resonance circuit by the inverter circuit Adjusting means;
A power supply device comprising:

  When the relative position of the primary coil and the secondary coil deviates from the appropriate position, the resonance state of the primary side resonance circuit and the secondary side resonance circuit deviates from the optimum resonance state, and the battery is supplied from the power supply device. The efficiency of transmitting power to the system is reduced. At this time, the value of the power factor determined based on the primary side current and the primary side voltage becomes small. According to the power supply device having the above configuration, the power factor is calculated based on the primary current and the primary voltage, and when the power factor falls below the threshold value, the power factor is increased. Adjusting at least one of the capacitance of the series resonant capacitor adjustment circuit in the primary side resonance circuit, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary side resonance circuit by the inverter circuit To do. As a result, even when the relative positions of the primary coil and the secondary coil deviate from the proper positions, the resonance states of the primary side resonance circuit and the secondary side resonance circuit are changed to the proper resonance states at the deviated positions. Can be corrected. For example, since it is not necessary to prepare a large number of primary coils for correcting the resonance state, an increase in size of the power supply device can be suppressed. Therefore, a reduction in the efficiency of power transmission due to the relative displacement between the primary coil and the secondary coil and a primary current resulting from the reduction in efficiency without causing an increase in the size of the power supply device. Problems such as heat generation due to an increase (overcurrent) can be suppressed.

  Furthermore, according to the power supply device having the above configuration, occurrence of a decrease in power transmission efficiency due to a relative displacement between the primary coil and the secondary coil is determined based on the power factor. Since the power factor does not change depending on the state of charge of the battery, for example, the state of the secondary side such as the secondary side current and the secondary side voltage, the primary coil and the secondary coil are not communicated with the secondary side. The occurrence of a decrease in the efficiency of power transmission due to the relative positional deviation can be appropriately determined only on the primary side.

[Application Example 2] The power supply device according to Application Example 1,
The characteristic adjusting means is configured to be able to execute the adjustment over n stages (n is a natural number of 2 or more), and each time the adjustment is performed, the power factor is compared with the threshold value. And repeat the adjustment at most n times until the power factor is greater than or equal to the threshold value,
A power supply device that continues charging when the power factor becomes equal to or greater than the threshold value within n adjustments.

  According to the power supply device having the above configuration, the resonance state of the primary side resonance circuit and the secondary side resonance circuit is brought close to an appropriate resonance state over a plurality of stages while comparing the power factor and the threshold value. Can do. As a result, when the relative positions of the primary coil and the secondary coil deviate from the proper positions, the resonance states of the primary side resonance circuit and the secondary side resonance circuit are changed to the proper resonance states at the deviated positions. The battery can be charged with a more accurate correction.

[Application Example 3] The power supply device according to Application Example 2, further including:
A power supply apparatus comprising: a warning unit that warns a user when the power factor falls below the threshold value after performing the adjustment at the nth stage.

  According to the power supply apparatus having the above configuration, if the power factor still falls below the threshold value even after the adjustment at a predetermined stage, a warning is given to the user. Therefore, when the relative positions of the primary coil and the secondary coil are shifted so as not to be sufficiently adjusted, the user can be made aware of this fact. As a result, the user can take measures such as changing the relative positions of the primary coil and the secondary coil.

[Application Example 4] The power supply device according to any one of Application Examples 1 to 3, further comprising:
During charging, the power factor change amount monitored is continuously compared with a predetermined abnormality change amount. If the power factor change amount exceeds the abnormal change amount, an abnormality related to charging is detected. A power supply device comprising an abnormality detection means for determining that a problem has occurred.

  According to the power supply device having the above-described configuration, the comparison of the power factor change amount and the predetermined abnormality change amount is continuously performed during the charging, whereby an abnormality related to charging (for example, the primary coil and the secondary coil). Occurrence of foreign matter in the gap) can be detected. As a result, when an abnormality relating to charging occurs, it is possible to take measures such as stopping charging or notifying the user, thereby suppressing heat generation or the like caused by the abnormality relating to charging.

Application Example 5 A power supply device that supplies power for charging the battery in a non-contact manner using electromagnetic induction to a battery system including a secondary resonance circuit including a secondary coil and a battery. Because
A primary side resonance circuit including a primary coil that generates a magnetic field for supplying AC power to the battery system via the secondary coil by electromagnetic induction;
Current detection means for detecting a primary current which is a current of the primary resonance circuit;
At least one of a series resonant capacitor adjustment circuit and an inductance adjustment circuit in the primary side resonance circuit;
An inverter circuit for supplying the AC power to the primary side resonance circuit;
The primary current detected by the current detection means is compared with a threshold value that is larger than a target value, and when the primary current exceeds the threshold value, the primary current is The capacitance of the series resonance capacitor adjustment circuit, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary resonance circuit by the inverter circuit so as to approach the target value Characteristic adjusting means for adjusting at least one of them,
A power supply device comprising:

  When the relative position between the primary coil and the secondary coil is deviated from the appropriate position and the efficiency of transmitting power from the power supply device to the battery system is reduced, the secondary current is charged at a constant level. The primary current becomes larger than the target value. According to the power supply device having the above configuration, when the primary side current exceeds a threshold value that is larger than the target value, the static current of the series resonant capacitor adjustment circuit is adjusted so that the primary side current approaches the target value. At least one of the capacitance, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary side resonance circuit by the inverter circuit is adjusted. As a result, even when the relative positions of the primary coil and the secondary coil deviate from the proper positions, the resonance states of the primary side resonance circuit and the secondary side resonance circuit are changed to the proper resonance states at the deviated positions. Can be corrected. For example, since it is not necessary to prepare a large number of primary coils for correcting the resonance state, an increase in the size of the power supply device can be suppressed. Therefore, a reduction in the efficiency of power transmission due to the relative displacement between the primary coil and the secondary coil and a primary current resulting from the reduction in efficiency without causing an increase in the size of the power supply device. Problems such as heat generation due to an increase (overcurrent) can be suppressed. Furthermore, in order to determine the occurrence of a decrease in power transmission efficiency due to the relative displacement between the primary coil and the secondary coil based only on the primary current, the reduction in efficiency can be reduced with a simple configuration. The occurrence can be judged.

[Application Example 6] The power supply device according to Application Example 5,
The characteristic adjusting means is configured to be able to execute the adjustment over n stages (n is a natural number of 2 or more), and each time the adjustment is performed, the primary current and the threshold value Making a comparison and repeating the adjustment at most n times until the primary current is below the threshold,
A power supply device that continues charging when the primary current becomes equal to or less than the threshold value within the n times of the adjustment.

  According to the power supply device having the above configuration, the resonance state of the primary side resonance circuit and the secondary side resonance circuit is changed to an appropriate resonance state over a plurality of stages while comparing the primary side current and the threshold value. It can be corrected. As a result, even when the relative positions of the primary coil and the secondary coil deviate from the proper positions, the resonance states of the primary side resonance circuit and the secondary side resonance circuit are changed to the proper resonance states at the deviated positions. Thus, the battery can be charged with high accuracy.

[Application Example 7] The power supply device according to Application Example 6, further including:
A power supply apparatus comprising: warning means for warning a user when the primary current exceeds the threshold value after performing the adjustment at the n-th stage.

  According to the power supply device having the above configuration, if the primary side current still exceeds the threshold value even after adjustment at a predetermined stage, a warning is given to the user. Therefore, when the relative positions of the primary coil and the secondary coil are shifted so as not to be sufficiently adjusted, the user can be made aware of that. As a result, the user can take measures such as changing the relative positions of the primary coil and the secondary coil.

  In addition, the power supply device according to any one of Application Example 5 to Application Example 7 sets an abnormality detection threshold value corresponding to a primary side current that varies depending on a charging state during charging, and the primary side current And the abnormality detection threshold value may be continuously compared, and if the primary current exceeds the abnormality detection threshold value, it may be determined that an abnormality relating to charging has occurred. In this way, when an abnormality occurs, it is possible to take measures such as stopping the charging or notifying the user, thereby suppressing heat generation or the like caused by the abnormality related to charging.

[Application Example 8] The power supply device according to any one of Application Examples 1 to 7,
The series resonant capacitor adjustment circuit includes:
A standard capacitor;
One or more capacitance reducing capacitors arranged in series with the standard capacitor;
A capacitance reducing capacitor changeover switch for switching the capacitance reducing capacitor between an effective state and an invalid state;
Including
The adjustment by the characteristic adjusting means is performed by switching the capacitance reducing capacitor from the invalid state to the valid state by turning the capacitance reducing capacitor changeover switch from on to off. A power supply device including reducing the capacitance of the power supply.

  According to the power supply device having the above configuration, by reducing the capacitance of the primary side resonance circuit, it is possible to suppress a decrease in the efficiency of power transmission due to the relative displacement between the primary coil and the secondary coil. can do. Unlike the primary coil, the capacitance reducing capacitor and the capacitance reducing capacitor changeover switch, which are configured to reduce the capacitance, do not need to consider the positional relationship with the secondary coil during charging. Since the degree of freedom is high (for example, it can be arranged at a location away from the primary coil), it is possible to suppress impairing the degree of freedom in designing the power supply device.

[Application Example 9] The power supply device according to any one of Application Example 1 to Application Example 8,
The inductance adjustment circuit is:
An inductance changeover switch for switching a part of the primary coil between an effective state and an invalid state;
The adjustment by the characteristic adjusting means is performed by switching a part of the primary coil from the valid state to the invalid state by turning the inductance changeover switch from off to on. A power supply device including reducing inductance.

  According to the power supply device having the above-described configuration, by reducing the inductance of the primary side resonance circuit, it is possible to suppress a decrease in the efficiency of power transmission caused by the relative displacement between the primary coil and the secondary coil. Can do. The inductance changeover switch that disables a part of the primary coil, which is a configuration for reducing the inductance, can be greatly reduced in size compared to the case where a plurality of primary coils are prepared. The increase in size can be effectively suppressed.

[Application Example 10] The power supply device according to any one of Application Example 1 to Application Example 9,
The adjustment by the characteristic adjusting means includes reducing the frequency of the alternating current supplied to the primary side resonance circuit by the inverter circuit.

  According to the power supply device having the above-described configuration, the power caused by the relative displacement between the primary coil and the secondary coil is reduced by reducing the frequency of the alternating current supplied to the primary-side resonance circuit by the inverter circuit. A decrease in transmission efficiency can be suppressed. Moreover, since it is not necessary to provide a special structure in the primary side resonance circuit, the enlargement of the power supply device can be effectively suppressed.

  The present invention can be realized in various forms, for example, a control method and control device for a power supply device, a computer program for realizing the function of the method or device, and recording the computer program It can be realized in the form of a recorded recording medium.

It is a figure which shows the electrical constitution of the system which performs non-contact charge in 1st Example. It is a figure which shows the usage example which charges the battery 240 of the battery system 200 using the electric power supply apparatus. It is a flowchart which shows the process step of the charge process of 1st Example. It is a flowchart which shows the process step of the charge process of 1st Example. It is an operation | movement table | surface which shows a response | compatibility with the state of the primary side resonance circuit 160, and operation | movement of switch SW1-SW3. It is a figure explaining charge control. It is a figure for demonstrating the improvement of the power factor and transmission efficiency by adjustment of the characteristic of the primary side resonance circuit. It is a figure which shows the electrical constitution of the system which performs non-contact charge in 2nd Example. It is a flowchart which shows the process step of the charge process of 2nd Example. It is a figure which shows the relationship between the primary side electric current in case charging is performed by constant current control, and transmission efficiency.

A. First embodiment:
FIG. 1 is a diagram showing an electrical configuration of a system that performs contactless charging in the first embodiment. This system includes a power supply device 100 and a battery system 200 including a battery.

  The power supply apparatus 100 is an apparatus that supplies power for charging a battery included in the battery system 200 to the battery system 200 in a non-contact manner using electromagnetic induction. The power supply apparatus 100 includes a power source 110, a primary side rectifier circuit 120, an inverter circuit 130, a current detector 140, a voltage detector 150, a primary side resonance circuit 160, a control circuit 170, and a battery system. 200 includes a primary-side communication circuit 180 for communicating with 200.

  The power source 110 is an AC power source such as a household power source of 100V or 200V. The primary side rectifier circuit 120 is a circuit that rectifies AC power supplied from the power supply 110 and converts it into DC power. The inverter circuit 130 is a circuit that switches the DC power output from the primary side rectifier circuit 120 to generate AC power of an arbitrary frequency and supplies it to the primary side resonance circuit 160. The inverter circuit 130 is a high-frequency full-bridge inverter that can generate AC power having a frequency of about 20 kHz (kilohertz), for example. The current detector 140 is a circuit that detects a current flowing through the primary side resonance circuit 160 (hereinafter also referred to as a primary side current Iin). The voltage detector 150 is a circuit that detects a voltage applied to the primary side resonance circuit 160 (hereinafter also referred to as a primary side voltage Vin).

  The primary side resonance circuit 160 is an LC series resonance circuit for transmitting power in a non-contact manner to a secondary side resonance circuit 210 of the battery system 200 described later. The primary side resonance circuit 160 includes a standard capacitor Cs, a first capacitance reduction capacitor C1, and a second capacitance reduction capacitor C2 as series resonance capacitors. These three capacitors are connected in series. The standard capacitor Cs is always enabled. On the other hand, the first capacitance decreasing capacitor C1 is configured to be switchable between an effective state and an invalid state by the first capacitance decreasing capacitor changeover switch SW1. The second capacitance reducing capacitor C2 is configured to be switchable between an effective state and an invalid state by a second capacitance reducing capacitor changeover switch SW2.

  The primary side resonance circuit 160 further includes a primary coil L1 arranged in series with a series resonance capacitor. The primary coil L1 is formed, for example, by winding a litz wire around a ferrite core as a core material. A part of the primary coil L1 is configured to be switchable between an effective state and an invalid state by an inductance changeover switch SW3. As a result, the inductance of the primary coil L1 can be switched in two stages by switching the inductance changeover switch SW3. Here, the capacitor and the coil being in an ineffective state means that both the electrodes of the capacitor and the coil are short-circuited so that no potential difference is generated between the two electrodes. “A capacitor or coil is in an effective state” means that both electrodes of the capacitor and the coil are not short-circuited and a potential difference can occur between the electrodes.

  The control circuit 170 is a circuit that controls the operation of the power supply apparatus 100, and is a general-purpose computer including a CPU and a memory, or hardware designed specifically for realizing control of the power supply apparatus 100. is there. The control circuit 170 implements functions as a power factor calculation unit M1, an inverter control unit M2, a state control unit M3, and a warning unit M4, for example, by executing a control program. The power factor calculation unit M1 calculates the power factor of the primary side resonance circuit 160 based on the primary side current detected by the current detector 140 and the primary side voltage detected by the voltage detector 150. . Here, when the phase difference between the primary side current and the primary side voltage is θ (positive when the primary side current is delayed with respect to the primary side voltage), the power factor φ is expressed by tan θ. . The inverter control unit M2 controls the inverter circuit 130 to control the frequency of the AC power supplied to the primary side resonance circuit 160 to a desired value. The state control unit M3 controls the state of the primary side resonance circuit 160 based on the value of the power factor. Specifically, the state control unit M3 performs switching control of the first capacitance reduction capacitor changeover switch SW1, the second capacitance reduction capacitor changeover switch SW2, and the inductance changeover switch SW3 to perform the primary side resonance circuit 160. Is controlled to any one of a non-adjustment state, a one-step adjustment state, a two-step adjustment state, and a three-step adjustment state, which will be described later. The warning unit M4 issues a warning to the user based on the power factor value. The warning notifies the user that there is a problem in the power supply to the battery system 200. For example, the alarm in the vehicle, the display on the display device of the user's home, the user's mobile phone This is done in the form of e-mail.

  The battery system 200 includes a secondary side resonance circuit 210, a secondary side rectification circuit 220, a charging circuit 230, a battery 240, a motor drive circuit 250, a motor 260, and a secondary side communication circuit 270. Yes. The battery 240 is a rechargeable battery that can be repeatedly used as a DC power source by charging a nickel metal hydride battery, a lithium ion battery, or the like. The motor drive circuit 250 is a circuit that switches the DC power supplied from the battery 240 to generate AC power, and supplies the generated AC power to the motor 260 to drive the motor 260.

  The secondary side resonance circuit 210 is an LC parallel resonance circuit for receiving power from the primary side resonance circuit 160 of the power supply apparatus 100. The secondary resonance circuit 210 includes a secondary coil L2 and a parallel resonance capacitor Cp connected in parallel with the secondary coil L2. Similar to the primary coil L1, the secondary coil L2 is formed, for example, by winding a litz wire around a ferrite core as a core material. The secondary rectifier circuit 220 is a circuit that rectifies the alternating current received by the secondary resonant circuit 210 and converts it into direct current. The charging circuit 230 is a circuit that steps down or boosts the DC power output from the secondary side rectifier circuit 220 to convert it to power of a desired voltage and supplies it to the battery 240. Thereby, the charging circuit 230 charges the battery 240. The secondary side communication circuit 270 is a circuit that communicates with the primary side communication circuit 180 of the power supply apparatus 100.

  FIG. 2 is a diagram illustrating a usage example in which the battery 240 of the battery system 200 is charged using the power supply apparatus 100. In this example, the battery system 200 is mounted on a vehicle, and the secondary coil L2 of the battery system 200 is disposed in the vicinity of the lower end of the vehicle main body so that the central axis is parallel to the vertical direction. In the power supply apparatus 100, at least the primary coil L1 is installed under the ground where the vehicle can be parked. The primary coil L1 is disposed in the vicinity of the ground surface so that the central axis is parallel to the vertical direction.

  The charging operation (charging process) in the usage example shown in FIG. 2 will be described. 3 and 4 are flowcharts showing processing steps of the charging process of the first embodiment. FIG. 5 is an operation table showing the correspondence between the state of the primary side resonance circuit 160 and the operation of the switches SW1 to SW3. FIG. 6 is a diagram for explaining the charging control. FIG. 7 is a diagram for explaining improvement of the power factor and transmission efficiency by adjusting the characteristics of the primary side resonance circuit 160.

  First, when charging, the user parks the vehicle so that the position of the secondary coil L2 with respect to the primary coil L1 is an appropriate position. In this embodiment, the appropriate position is a position where the central axis of the primary coil L1 and the central axis of the secondary coil L2 are aligned on the same straight line. The distance between the primary coil L1 and the secondary coil L2 at this time is also referred to as an appropriate gap. However, in reality, the position of the secondary coil L2 with respect to the primary coil L1 is changed from the proper position to the center axis direction of the coil and / or the center axis due to a shift in the stop position of the vehicle, a change in the size of the tire of the vehicle, or the like. It can shift in the direction perpendicular to After the vehicle is parked, for example, when the user gives a charging instruction via an operating means (button or the like) (not shown), the charging process is started.

  When the charging process is started, the state control unit M3 of the control circuit 170 controls the primary side resonance circuit 160 to an unadjusted state (FIG. 3: step S10). Specifically, as shown in FIG. 5, the state control unit M3 turns on the first capacitance reducing capacitor changeover switch SW1, turns on the second capacitance reduction capacitor changeover switch SW2, and turns on the inductance changeover switch SW3. Is controlled to OFF. In the non-adjustment state, the standard capacitor Cs is valid, and the first capacitance reducing capacitor C1 and the second capacitance reducing capacitor C2 are invalid. Further, all of the primary coil L1 becomes effective.

  Next, the power supply device 100 and the battery system 200 cooperate to perform charging control (step S20). Specifically, first, the inverter control unit M <b> 2 of the control circuit 170 of the power supply device 100 performs switching control of the inverter circuit 130, and supplies AC power of frequency f to the primary side resonance circuit 160. Then, since an alternating current flows through the primary coil L1, a magnetic field is generated around the primary coil L1. This magnetic field generates an electromotive force in the secondary coil L2 of the secondary side resonance circuit 210 by electromagnetic induction. As a result, electric power is supplied to the battery system 200 in a contactless manner. In other words, it can be said that the primary coil L1 and the secondary coil L2 form a transformer.

  When power is supplied to the battery system 200, the charging circuit 230 of the battery system 200 charges the battery 240 using the supplied power. Specifically, as shown in FIG. 6, the charging circuit 230 supplies the battery 240 to the battery 240 from the start of charging until the time Tex when the SOC (State of Charge) of the battery 240 exceeds a specified value. Charging is performed so that a constant current is maintained (constant current control). The charging circuit 230 performs charging so that the voltage applied to the battery 240 is constant between time Tex and the end of charging (constant voltage control). By performing such control, the charging circuit 230 can charge the battery 240 quickly and while suppressing overcharge.

  Immediately after the start of charging control, the power factor calculation unit M1 of the control circuit 170 acquires electrical signals from the current detector 140 and the voltage detector 150, and detects the primary side current Iin and the primary side voltage Vin, respectively. (Step S30). The power factor calculation unit M1 calculates the power factor φa based on the detected primary side current Iin and the primary side voltage Vin (step S40).

  Here, in a state where the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position, the resonance frequency of the primary side resonance circuit 160 in the non-adjusted state and the resonance frequency of the secondary side rectifier circuit 220 are the same. The circuit is configured as follows. Further, the frequency f of the AC power described above is set to the resonance frequency. In such an ideal state, the phase difference between the primary side current and the primary side voltage is 0, and the power factor is 1. In such resonance type non-contact power transmission, even when the primary coil L1 and the secondary coil L2 are non-contact, power can be transmitted with high transmission efficiency. Here, the transmission efficiency is expressed by (secondary side current × secondary side voltage) / (primary side current × primary side voltage).

  An ideal resonance state in which the power factor is 1 is limited to when the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position. The positional deviation from the proper position causes the resonance state to deviate from the ideal resonance state. As a result, the power factor decreases from 1, and the power transmission efficiency from the primary side resonance circuit 160 to the secondary side resonance circuit 210 decreases. When the transmission efficiency decreases, the primary current Iin increases from the target value by the amount corresponding to the decrease in transmission efficiency (overcurrent). The thermal energy corresponding to this increase in current is released as a switching loss in the inverter circuit 130 and generates heat in the inverter circuit 130. It can be said that the power factor is an index representing transmission efficiency. In this embodiment, a power factor (hereinafter referred to as a target power factor φnm) corresponding to a target value (target efficiency) of transmission efficiency is used as a threshold value.

  When the power factor φa is calculated, the control circuit 170 determines whether or not the calculated power factor φa is greater than or equal to the target power factor φnm (step S50). When determining that the power factor φa is equal to or higher than the target power factor φnm (step S50: YES), the control circuit 170 stores the power factor φa in the memory as the reference power factor φX (step S60). When the power factor φa is equal to or higher than the target power factor φnm, the positional deviation of the secondary coil L2 with respect to the primary coil L1 is small, and as a result, the transmission efficiency is not lowered so much and the target efficiency is achieved. I can judge.

  On the other hand, when it is determined that the power factor φa is lower than the target power factor φnm (step S50: NO), the state control unit M3 of the control circuit 170 controls the state of the primary side resonance circuit 160 to a one-stage adjusted state (step). S70). That is, the state control unit M3 switches the state of the primary side resonance circuit 160 from the non-adjusted state to the one-step adjusted state so that power is applied to the first capacitance reducing capacitor C1. Specifically, as shown in FIG. 5, the state control unit M3 switches the first capacitance reduction capacitor changeover switch SW1 from ON to OFF. That is, the state control unit M3 switches the first capacitance reducing capacitor C1 from the invalid state to the valid state. When the power factor φa is lower than the target power factor φnm, it is possible to determine that the displacement of the secondary coil L2 with respect to the primary coil L1 is large, and as a result, the transmission efficiency is lowered and the target efficiency is not achieved. For this reason, in such a case, the state control unit M3 changes the state of the primary side resonance circuit 160 from the unadjusted state to one stage in order to adjust the characteristics of the primary side resonance circuit 160 so that the power factor becomes large. Switching to the adjustment state.

励磁リアクタンスＸ_０は、電力の伝送に有効な磁束に相当し、１次側漏れリアクタンスＸ_１および２次側漏れリアクタンスＸ_２は、電力の伝送に無効な磁束に相当する。また、１次コイルＬ１から２次コイルＬ２への電力の伝送効率の最大値η_maxは以下の式（２）で表される。

Here, a specific method for adjusting the characteristics of the primary side resonance circuit 160 so as to increase the power factor will be described. The impedance Z viewed from the primary resonance circuit 160 of the power supply device 100 during charging is expressed by the following equation (1).

Excitation reactance X ₀ corresponds to a valid flux transmission power, the primary leakage reactance X ₁ and the secondary leakage reactance X ₂ corresponds to the invalid magnetic flux transmission power. The maximum value η _max of the power transmission efficiency from the primary coil L1 to the secondary coil L2 is expressed by the following equation (2).

Here, a state in which the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position and the primary side resonance circuit 160 is in an unadjusted state is referred to as a standard state. In the standard state, the power factor is 1. A power factor of 1 is equivalent to imaginary part = 0 in equation (1). The deviation of the position of the secondary coil L2 is generated to the primary coil L1, the excitation reactance X ₀ is decreased, the primary leakage reactance X ₁ and the secondary leakage reactance X ₂ is increased. As a result, the power factor falls below 1, that is, the relationship of imaginary part = 0 in equation (1) is broken, and the imaginary part becomes a positive value. Further, it can be seen that the transmission efficiency is lowered because the value b of the equation (2) is decreased.

Increasing the power factor is equivalent to bringing the imaginary part closer to zero. The technique of approximating the imaginary part to zero if the imaginary portion is a positive value, and increasing the reactance X _s of the series resonant capacitor, and increasing the excitation reactance X _0, 2 primary leakage reactance reducing the X ₂ is considered from the equation (1). Here, the reactance X _s of the series resonant capacitor is X _s = 1 / 2πfC (f: frequency of alternating current supplied to the primary side resonance circuit 160, C: capacitance of the series resonant capacitor). To increase the reactance X _s of the series resonance capacitor decreases the capacitance C of the series resonance capacitor, or may be reduced the frequency of alternating current supplied to the primary side resonance circuit 160. Also, increasing the excitation reactance X _0, To reduce the secondary leakage reactance X _2, may be reduced inductance of the primary coil L1.

That is, the following three methods can be considered as specific methods for adjusting the characteristics of the primary side resonance circuit 160 so that the power factor is increased.
1) Decrease the capacitance C of the series resonance capacitor 2) Decrease the frequency of the alternating current supplied to the primary side resonance circuit 160 3) Decrease the inductance of the primary coil L1 In order to increase the power factor, adjusting the characteristics of the primary-side resonant circuit 160, an increase of the excitation reactance X _0, and / or, since the decrease in the secondary leakage reactance X ₂ occurs, it can be seen that to improve the transmission efficiency from the equation (2).

  Describing conceptually with reference to FIG. 7, the power factor and the transmission efficiency are in a relationship that forms a straight line in which the transmission efficiency increases as the power factor increases. Different straight lines are obtained when the primary side resonance circuit 160 is in an unadjusted state and when the primary side resonance circuit 160 is in an adjusted state. In the standard state, that is, when the primary side resonance circuit 160 is in an unadjusted state and the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position, as shown by a point A in FIG. Is 1 which is the maximum value, and the transmission efficiency is also ηa which is the maximum value of this system. Point B in FIG. 7 indicates that the position of the secondary coil L2 with respect to the primary coil L1 is appropriate such that the power factor when the primary side resonance circuit 160 is in the unadjusted state is a value Ψb that is lower than the target power factor φnm. This corresponds to a state shifted from the position (hereinafter referred to as a large position shift state). In this case, the transmission efficiency ηb is significantly lower than the transmission efficiency ηa when the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position. Here, when the state of the primary side resonance circuit 160 is switched from the non-adjusted state to the adjusted state, as shown by the arrow L in FIG. 7, the straight line indicating the relationship between the power factor and the transmission efficiency is the same power factor. Will change to another straight line where the transmission efficiency will be lower. However, when the state of the primary side resonance circuit 160 is switched from the non-adjusted state to the adjusted state, the power factor can be increased while the misalignment remains large. In the example of FIG. 7, as indicated by an arrow M, the power factor is increased from the value Ψb to a value Ψc greater than the target power factor φnm by switching the state of the primary side resonance circuit 160 from the non-adjusted state to the adjusted state. It has been shown. As a result, it is possible to improve the transmission efficiency from the value ηb to the value ηc while maintaining a large misalignment (point C in FIG. 7).

  Returning to the flowchart of FIG. When the primary side resonance circuit 160 is switched from the non-adjusted state to the one-stage adjusted state in step S70, compared to the non-adjusted state, a capacitor that is more effective as a series resonant capacitor is the standard capacitor Cs and the first capacitance reducing capacitor. It increases to two of C1. When the number of capacitors connected in series in this way increases, the combined capacitance decreases, so the capacitance of the series resonance capacitor of the primary side resonance circuit 160 decreases. That is, in step S70, the power factor is increased by decreasing the capacitance of the series resonant capacitor of the primary side resonance circuit 160.

  Thereafter, while continuing the charge control (step S80), the power factor calculation unit M1 of the control circuit 170 detects the primary side current Iin and the primary side voltage Vin again (step S90), and detects the detected primary side. Based on the current Iin and the primary side voltage Vin, the power factor φb is calculated (step S100). Subsequently, the control circuit 170 determines whether or not the calculated power factor φb is equal to or greater than the target power factor φnm (step S110). If it is determined that the power factor φb is equal to or higher than the target power factor φnm (step S110: YES), the control circuit 170 stores the power factor φb in the memory as the reference power factor φX (step S120). When the power factor φb is equal to or greater than the target power factor φnm, it can be determined that the target efficiency has been achieved by adjusting the characteristics of the primary side resonance circuit 160 in step S70.

  On the other hand, when it is determined that the power factor φb is lower than the target power factor φnm (step S110: NO), the state control unit M3 of the control circuit 170 controls the state of the primary side resonance circuit 160 to a two-stage adjustment state (step) S130). That is, the state control unit M3 switches the state of the primary side resonance circuit 160 from the one-stage adjustment state to the two-stage adjustment state. Specifically, as shown in FIG. 5, the state control unit M3 switches the second capacitance reduction capacitor changeover switch SW2 from ON to OFF, and enables the second capacitance reduction capacitor C2 from the invalid state. The power is applied to the second capacitance reducing capacitor C2. When the power factor φb is lower than the target power factor φ, the positional deviation of the secondary coil L2 with respect to the primary coil L1 is large, and the transmission efficiency is low even when the primary side resonance circuit 160 is in the one-stage adjustment state, and the target efficiency is reduced. It can be judged that it has not been achieved. Therefore, in such a case, the state control unit M3 changes the state of the primary side resonance circuit 160 from the one-stage adjustment state in order to adjust the characteristics of the primary side resonance circuit 160 so that the power factor is further increased. Switching to the two-stage adjustment state.

  When the primary side resonance circuit 160 is switched to the two-stage adjustment state, three capacitors that are effective as series resonance capacitors are the standard capacitor Cs, the first capacitance reduction capacitor C1, and the second capacitance reduction capacitor C2. Increase. As a result, the capacitance of the series resonant capacitor of the primary side resonance circuit 160 is further reduced and the power factor is increased.

  Thereafter, while continuing the charging control (step S140), the power factor calculation unit M1 of the control circuit 170 again detects the primary side current Iin and the primary side voltage Vin (step S150), and calculates the power factor φc. (Step S160). Subsequently, the control circuit 170 determines whether or not the calculated power factor φc is equal to or greater than the target power factor φnm (step S170). When determining that the power factor φc is equal to or greater than the target power factor φnm (step S170: YES), the control circuit 170 stores the power factor φc in the memory as the reference power factor φX (step S180). When the power factor φc is equal to or greater than the target power factor φnm, it can be determined that the target efficiency has been achieved by adjusting the characteristics of the primary side resonance circuit 160 in step S130.

  On the other hand, when it is determined that the power factor φc is lower than the target power factor φnm (step S180: NO), the state control unit M3 of the control circuit 170 controls the state of the primary side resonance circuit 160 to a three-stage adjustment state (step S180). S190). That is, the state control unit M3 switches the state of the primary side resonance circuit 160 from the two-stage adjustment state to the three-stage adjustment state. Specifically, as shown in FIG. 5, the state control unit M3 switches the inductance changeover switch SW3 from OFF to ON to switch a part of the primary coil L1 from the valid state to the invalid state. The inductance of the coil L1 is reduced. When the power factor φc is lower than the target power factor φnm, the positional deviation of the secondary coil L2 with respect to the primary coil L1 is large, and the transmission efficiency is still low even when the primary side resonance circuit 160 is set in a two-stage adjustment state. It can be judged that it has not been achieved. Therefore, in such a case, the state control unit M3 changes the state of the primary side resonance circuit 160 from the two-stage adjustment state in order to adjust the characteristics of the primary side resonance circuit 160 so that the power factor is further increased. It is switched to the three-stage adjustment state.

  When the primary side resonance circuit 160 is switched to the three-stage adjustment state, a part of the primary coil L1 becomes invalid, thereby reducing the inductance of the primary coil L1. As a result, the power factor increases.

  Thereafter, while continuing the charge control (step S200), the power factor calculation unit M1 of the control circuit 170 again detects the primary side current Iin and the primary side voltage Vin (step S210), and calculates the power factor φd. (Step S220). Subsequently, the control circuit 170 determines whether or not the calculated power factor φd is equal to or greater than the target power factor φnm (step S230). When determining that the power factor φd is equal to or greater than the target power factor φnm (step S230: YES), the control circuit 170 stores the power factor φd in the memory as the reference power factor φX (step S240). When the power factor φd is equal to or greater than the target power factor φnm, it can be determined that the target efficiency has been achieved by adjusting the characteristics of the primary side resonance circuit 160 in step S190.

  On the other hand, when determining that the power factor φd is lower than the target power factor φnm (step S240: NO), the warning unit M4 of the control circuit 170 stops the charging control and executes a warning for the user (FIG. 4: step S300). ). When the power factor φd is lower than the target power factor φnm, the positional deviation of the secondary coil L2 with respect to the primary coil L1 is large, and the transmission efficiency is still low even when the primary side resonance circuit 160 is in the three-stage adjustment state. It can be judged that it has not been achieved. In such a case, it is determined that it is difficult to achieve the target efficiency by adjusting the characteristics of the primary side resonance circuit 160, and the warning unit M4 warns the user and takes measures such as correcting the parking position of the vehicle. Prompt.

  If the target power factor φnm is achieved in any of steps S60, S120, S180, and S240, the charging control is continued (step S250). Then, while continuing the charge control, the power factor calculation unit M1 of the control circuit 170 again detects the primary side current Iin and the primary side voltage Vin (step S260), and calculates the power factor φr (step S270). ). Then, the control circuit 170 determines that a difference Δφr between the reference power factor φX stored in the memory and the calculated power factor φr (a change amount Δφr of the power factor from the reference power factor φX) is a threshold for detecting an abnormality. It is determined whether or not the abnormal change amount Δφchg is exceeded (step S280). If it is determined that the change amount Δφr exceeds the abnormal change amount Δφchg (step S280: YES), the warning unit M4 of the control circuit 170 stops the charging control and issues a warning to the user (step S300). If the change amount Δφr exceeds the abnormal change amount Δφchg, it can be determined that some abnormality has occurred during charging. Possible abnormalities during charging include intrusion of a metallic foreign object such as an empty can between the primary coil L1 and the secondary coil L2 (between the vehicle and the ground surface in the example of FIG. 2).

  On the other hand, when it is determined that the difference Δφr does not exceed the abnormal change amount Δφchg (step S280: NO), the control circuit 170 determines whether or not the charging is completed (step S290). The charging circuit 230 of the battery system 200 notifies the control circuit 170 of the end of charging through communication using the secondary side communication circuit 270. The control circuit 170 determines whether or not charging has been completed based on the presence or absence of the notification. If charging has not ended (step S290: NO), the control circuit 170 returns to step S250 and repeats the above-described processing. On the other hand, when the charging is completed (step S290: YES), the control circuit 170 ends the charging.

In other words, the processing contents of steps S250 to S300 are as follows:
1) Monitor the amount of change Δφr of the power factor from the reference power factor φX during charging when the target power factor φnm is achieved and continue charging. 2) The amount of change Δφr being monitored becomes the amount of abnormal change Δφchg. 3) When the monitored change amount Δφr exceeds the abnormal change amount Δφchg, it is determined that an abnormality relating to charging has occurred, and charging is stopped and the user is warned.

  As can be understood from the above description, the standard capacitor Cs, the first capacitance reducing capacitor C1, the second capacitance reducing capacitor C2, the first capacitance reducing capacitor changeover switch SW1 in the present embodiment, 2 and the capacitance reduction capacitor changeover switch SW2 as a whole correspond to the series capacitor adjustment circuit in the claims, and the inductance changeover switch SW3 in the present embodiment corresponds to the inductance adjustment circuit in the claims. The state control unit M3 in the embodiment corresponds to the characteristic adjustment unit in the claims.

  According to the first embodiment described above, the power factors φa to φc are calculated based on the primary side current Iin and the primary side voltage Vin, and the power factors φa to φc are below the target power factor φnm. In addition, the capacitance or inductance of the series resonant capacitor in the primary side resonance circuit 160 is adjusted so as to increase the power factor. As a result, even when the relative positions of the primary coil L1 and the secondary coil L2 are deviated from the proper positions, the resonance states of the primary side resonance circuit 160 and the secondary side resonance circuit 210 are changed at the deviated positions. It is possible to approach an appropriate resonance state. For example, since it is not necessary to prepare a large number of primary coils in order to correct the resonance state, an increase in size of the power supply device 100 can be suppressed. Accordingly, it is possible to suppress a reduction in power transmission efficiency due to a relative displacement between the primary coil L1 and the secondary coil L2 without causing an increase in the size of the power supply apparatus 100. A decrease in the efficiency of power transmission causes an increase (overcurrent) in the primary side current Iin, and the overcurrent causes problems such as heat generation.

  Further, according to the first embodiment, based on the power factors φa to φd, the occurrence of a decrease in power transmission efficiency due to the relative displacement between the primary coil L1 and the secondary coil L2 is determined. Yes. The power factors φa to φd indicate the charging status of the battery 240, for example, the type of control of the charging circuit 230 (whether it is constant current control or constant voltage control), secondary current, secondary voltage, etc. Since it does not change depending on the situation of the battery system 200, the power supply apparatus can reduce the efficiency of power transmission due to the relative displacement between the primary coil L1 and the secondary coil L2 without communicating with the battery system 200. An appropriate judgment can be made with 100 alone.

  Further, the primary side resonance circuit 160 is configured to be able to adjust the characteristics in three stages. The control circuit 170 compares the power factor with the target power factor φnm every time one stage of adjustment is performed, and the characteristic is repeated up to three times until the power factor becomes equal to or higher than the target power factor φnm. The adjustment is repeated. When the power factor becomes equal to or higher than the target power factor φnm until the characteristic of the primary side resonance circuit 160 is adjusted three times, the charging is continued. That is, the resonance state of the primary side resonance circuit 160 and the secondary side resonance circuit 210 is brought close to an appropriate resonance state over three stages while comparing the power factor and the target power factor φnm which is a threshold value. Can do. As a result, when the relative positions of the primary coil L1 and the secondary coil L2 deviate from the proper positions, the resonance states of the primary side resonance circuit 160 and the secondary side resonance circuit 210 are changed to the positions where the deviation occurred. The battery can be charged by correcting with an appropriate resonance state with high accuracy. In the above-described embodiment, the characteristics of the primary side resonance circuit 160 can be adjusted over three stages. However, any number of n stages can be obtained by appropriately changing the number of first capacitance reducing capacitors. You may comprise so that the characteristic of the primary side resonance circuit 160 can be adjusted over (n is a natural number).

  Furthermore, according to the first embodiment, if the power factor is still below the target power factor φnm even after the three-stage adjustment, a warning is given to the user. As a result, when the relative positions of the primary coil L1 and the secondary coil L2 are shifted so as not to be sufficiently adjusted, the user can be made aware of that. As a result, the user can take measures such as changing the relative positions of the primary coil L1 and the secondary coil L2, that is, correcting the parking position of the vehicle on which the battery system 200 is mounted. . Note that the warning may be omitted and the charging may be stopped.

  Further, according to the first embodiment, during the charging period after the power factor reaches the target power factor φnm, the power factor variation Δφr and the abnormal variation Δφchg are continuously compared and charged. It is possible to detect the occurrence of an abnormality related to. As a result, when an abnormality relating to charging occurs, it is possible to take measures such as stopping charging or notifying the user, thereby suppressing heat generation or the like caused by the abnormality relating to charging. Note that the process of monitoring the amount of change Δφr and detecting an abnormality related to charging may be omitted.

B. Second embodiment:
FIG. 8 is a diagram showing an electrical configuration of a system that performs contactless charging in the second embodiment. Since the electrical configuration of the battery system 200 of the second embodiment is the same as that of the battery system 200 of the first embodiment, the same reference numerals as those in FIG. The electrical configuration of the power supply device 100A of the second embodiment differs from the power supply device 100 of the first embodiment in that a control circuit 170A includes a current acquisition unit M1A instead of the power factor calculation unit M1. And a point where the voltage detector 150 is not provided. Since the other configuration of the power supply device 100A of the second embodiment is the same as that of the power supply device 100 of the first embodiment, the same components are denoted by the same reference numerals as in FIG. Description is omitted.

  FIG. 9 is a flowchart showing the processing steps of the charging process of the second embodiment. In the flowchart of FIG. 9, the same processing steps as those in the flowchart of the first embodiment shown in FIGS. 3 and 4 are denoted by the same reference numerals as those in FIGS. 3 and 4. A ”is attached. In the charging process, in the first embodiment, whether the transmission efficiency is reduced due to the displacement of the secondary coil L2 with respect to the primary coil L1 by comparing the power factor with the target power factor φnm. Judging. Instead, in the second embodiment, the primary side current is compared with the current threshold value Inm set to a value larger than the target current which is the target value, whereby the secondary coil L2 with respect to the primary coil L1 is compared. It is determined whether or not a decrease in transmission efficiency due to the positional deviation has occurred. The charging control in the second embodiment is performed by constant current control (control for keeping the secondary current constant). For this reason, the target value of the primary current is a constant value, and a constant value can be used for the current threshold value Inm. When the charge control is performed by the constant voltage control, the target value of the primary side current Iin varies depending on the state of charge of the battery 240 (recognized by the SOC or the like). Therefore, the current threshold value Inm may be changed according to the target value of the primary side current Iin.

  Specifically, as shown in FIG. 9, immediately after charging is started in an unadjusted state, the current acquisition unit M1A of the control circuit 170A detects the primary side current Ia (step S30A), and the primary side current Ia is compared with the current threshold value Inm (step S50A). As a result, when the primary current Ia exceeds the current threshold value Inm (step S50A: NO), the control circuit 170A is allowed due to the positional deviation of the secondary coil L2 with respect to the primary coil L1. It can be determined that a reduction in transmission efficiency exceeding the range has occurred and an overcurrent has occurred. In this case, the state control unit M3 of the control circuit 170A switches the state of the primary side resonance circuit 160 from the non-adjustment state to the one-stage adjustment state, similarly to the first embodiment (step S70). When the primary current Ia is equal to or less than the current threshold value Inm (step S50A: YES), the control circuit 170A decreases the transmission efficiency due to the positional deviation of the secondary coil L2 with respect to the primary coil L1. Is determined to be within the allowable range. In this case, the control circuit 170A stores the primary current Ia as the reference current IX (step S60A) and continues charging.

  After switching to the one-step adjustment state, a process for determining whether to switch to the two-step adjustment state or to continue charging (steps S90A to S120A), and after switching to the two-step adjustment state, further three-step adjustment state To determine whether to continue charging or to continue charging (steps S150A to S180A), and determine whether to continue charging or stop charging and warn the user after switching to the three-stage adjustment state The processing (steps S210A to S140A) is similarly performed based on a comparison between the primary side currents Ib to Id and the current threshold value Inm.

  FIG. 10 is a diagram showing the relationship between the primary current Iin and the transmission efficiency when charging is performed by constant current control. In the case where charging is performed by constant current control, the primary side current Iin and the transmission efficiency have a relationship of forming a convex curve so that the transmission efficiency decreases as the primary side current Iin increases. Different curves are obtained when the primary side resonance circuit 160 is in an unadjusted state and when the primary side resonance circuit 160 is in an adjusted state. In the standard state, that is, when the primary side resonance circuit 160 is in an unadjusted state and the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position, as shown by a point D in FIG. The side current Iin becomes the target value Id which is the minimum value, and the transmission efficiency becomes ηd which is the maximum value of this system. A point E in FIG. 10 indicates that the secondary side relative to the primary coil L1 is such that the primary side current Iin when the primary side resonance circuit 160 is in an unadjusted state becomes a value Ie exceeding the above-described current threshold value Inm. This corresponds to a state in which the position of the coil L2 is deviated from the appropriate position (a state in which the position deviation is large). In this case, the transmission efficiency ηe is significantly lower than the transmission efficiency ηd when the position of the secondary coil L2 with respect to the primary coil L1 is in an appropriate position. Here, when the state of the primary side resonance circuit 160 is switched from the non-adjusted state to the adjusted state, the straight line indicating the relationship between the primary side current Iin and the transmission efficiency is the same as shown by the arrow N in FIG. In the case of the secondary current Iin, the transmission efficiency changes to another straight line that lowers the transmission efficiency. However, when the state of the primary side resonance circuit 160 is switched from the non-adjusted state to the adjusted state, the primary side current Iin can be reduced and the transmission efficiency can be improved while maintaining a large misalignment. In the example of FIG. 10, as indicated by an arrow O, the primary side current Iin is decreased from the value Ie to the value If by switching the state of the primary side resonance circuit 160 from the non-adjustment state to the adjustment state. It can be seen that the efficiency is improved from the value ηe to the value ηf (see points E and F in FIG. 7).

  In the first embodiment, when the target power factor φnm is achieved and charging is continued, the change amount Δφr of the power factor from the reference power factor φX is monitored, and the monitored change amount Δφr is monitored. And an abnormal change amount Δφchg are detected to detect an abnormality related to charging. Instead, in the second embodiment, when the primary side current Iin below the current threshold value Inm is realized and charging is continued, the change amount ΔIr of the primary side current Iin from the reference current IX. Monitoring. Whether or not an abnormality related to charging has occurred is determined based on whether or not the change amount ΔIr being monitored exceeds the abnormal change amount ΔIchg.

  Specifically, as shown in FIG. 9, when the primary current Iin below the current threshold is realized in any of steps S60A, S120A, S180A, and S240A, the charging control is continued (step S250), the current acquisition unit M1A of the control circuit 170 detects the primary current Ir (step S260A). Then, the control circuit 170 determines whether or not the change amount ΔIr from the reference current IX stored in the memory of the detected primary current Ir exceeds the abnormal change amount ΔIchg that is a threshold value for detecting an abnormality. Is determined (step S280A). If it is determined that the change amount ΔIr exceeds the abnormal change amount ΔIchg (step S280A: YES), as in the first embodiment, the warning unit M4 of the control circuit 170 stops the charging control and issues a warning to the user. Execute (step S300). On the other hand, when determining that the change amount ΔIr does not exceed the abnormal change amount ΔIchg (step S280A: NO), the control circuit 170 determines whether or not the charging is finished (step S290), and the charging is not finished. In that case (step S290: NO), the process returns to step S250 and the above-described processing is repeated. On the other hand, when the charging is completed (step S290: YES), the control circuit 170 ends the charging.

  According to the second embodiment described above, when the primary side current Iin exceeds the current threshold current threshold value Inm which is a value larger than the target value, the primary side current Iin is reduced, that is, The capacitance or inductance of the series resonance capacitor in the primary side resonance circuit 160 is adjusted so as to approach the target value. As a result, even when the relative positions of the primary coil L1 and the secondary coil L2 are deviated from the proper positions, the resonance states of the primary side resonance circuit 160 and the secondary side resonance circuit 210 are changed at the deviated positions. It is possible to approach an appropriate resonance state. For example, since it is not necessary to prepare a large number of primary coils for correcting the resonance state, it is possible to suppress an increase in size of the power supply device 100A. Therefore, without causing an increase in size of the power supply apparatus 100A, the power transmission efficiency decreases due to the relative displacement between the primary coil L1 and the secondary coil L2, and the efficiency 1 decreases. Problems such as heat generation due to an increase in the secondary current (overcurrent) can be suppressed.

  Further, according to the second embodiment, it is determined whether or not the power transmission efficiency is reduced due to the relative displacement between the primary coil L1 and the secondary coil L2 based on only the primary side current Iin. Therefore, it is possible to determine the occurrence of the decrease in efficiency with a simple configuration.

  Further, the primary side resonance circuit 160 is configured to be able to adjust the characteristics in three stages. The control circuit 170 compares the primary side current Iin with the threshold current threshold value Inm every time one step of adjustment is performed until the primary side current Iin becomes equal to or less than the current threshold value Inm. The adjustment of characteristics is repeated up to three times. If the primary side current Iin becomes equal to or less than the current threshold value Inm before the characteristic of the primary side resonance circuit 160 is adjusted three times, the charging is continued. That is, while comparing the primary side current Iin and the current threshold value Inm, the resonance state of the primary side resonance circuit 160 and the secondary side resonance circuit 210 is brought close to an appropriate resonance state over three stages. Can do. As a result, as in the first embodiment, even when the relative positions of the primary coil L1 and the secondary coil L2 deviate from the proper positions, the resonance of the primary side resonance circuit 160 and the secondary side resonance circuit 210 is detected. The state can be accurately corrected by the appropriate resonance state at the shifted position, and the battery can be charged.

  Furthermore, according to the second embodiment, if the primary current Iin still exceeds the current threshold value Inm even after the three-stage adjustment, a warning is given to the user. As a result, as in the first embodiment, when the relative positions of the primary coil L1 and the secondary coil L2 deviate so that sufficient adjustment cannot be performed, the user can be made aware of that fact.

  Further, according to the second embodiment, the comparison between the change amount ΔIr of the primary side current and the change amount ΔIchg of the primary side current is performed during the charging period after the primary side current Iin less than the current threshold value Inm is realized. It is possible to detect the occurrence of abnormality related to charging by continuously performing the charging. As a result, as in the first embodiment, when an abnormality relating to charging occurs, it is possible to take measures such as stopping charging or notifying the user, thereby suppressing heat generation caused by the abnormality relating to charging. be able to.

C. Variations:
In addition, elements other than the elements claimed in the independent claims among the constituent elements in the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

・ First modification:
In the above embodiment, three specific methods for adjusting the characteristics of the primary side resonance circuit 160 described above, that is,
1) Decrease capacitance C of series resonance capacitor 2) Decrease frequency of alternating current supplied to primary side resonance circuit 160 3) Decrease inductance of primary coil L1 1) and 3) That is, the method of adjusting the reactance of the primary side resonance circuit 160 is used. In addition to or instead of the methods 1) and 3), the method 2) may be used. In this case, the switching control of the inverter circuit 130 by the inverter control unit M2 of the control circuit 170 may be changed to make the frequency f of the AC power supplied to the primary side resonance circuit 160 smaller than the standard state. In this way, when the position of the secondary coil L2 with respect to the primary coil L1 deviates from the appropriate position, the power factor of the system including the power supply device 100 and the battery system 200 is increased and the power transmission efficiency is improved. be able to. The methods 1) to 3) may be used in combination as appropriate, or may be used alone.

  Here, advantages of the above three specific methods will be described. 1), that is, when the capacitance of the series resonant capacitor is reduced, the configuration for reducing the capacitance (in the above embodiment, the first capacitance reduction capacitor C1 and the second capacitance reduction). Unlike the primary coil L1, the capacitor C2, the first capacitance reduction capacitor changeover switch SW1, and the second capacitance reduction capacitor changeover switch SW2) need to consider the positional relationship with the secondary coil L2 during charging. Therefore, since the freedom degree of arrangement | positioning is high (for example, it can arrange | position also in the place distant from the primary coil L1), it can suppress impairing the freedom degree of design of the electric power supply apparatuses 100 and 100A.

  In the method 2), that is, when the frequency f of the alternating current supplied to the primary side resonance circuit 160 is reduced, it is only necessary to change the switching control of the inverter circuit 130. There is no need to provide any special configuration, and the increase in size of the power supply devices 100 and 100A can be effectively suppressed. Further, the frequency f can be easily changed in multiple stages.

  In the method 3), that is, when the inductance of the primary coil L1 is reduced, the inductance changeover switch SW3, which is a configuration for reducing the inductance, is greatly compared with the case where a plurality of primary coils are prepared. Since the size can be reduced, the increase in size of the power supply devices 100 and 100A can be effectively suppressed.

・ Second modification:
In the above embodiment, the characteristics of the primary side resonance circuit 160 are adjusted stepwise (non-continuously) using the switches SW1 to SW3, but the characteristics of the primary side resonance circuit 160 are continuously adjusted. You may do it. For example, the transmission efficiency may be improved by adjusting the capacitance of the series resonance capacitor of the primary side resonance circuit 160 using a variable capacitor.

・ Third modification:
Both the process for determining the decrease in transmission efficiency in the first embodiment based on the power factor and the process for determining the decrease in transmission efficiency in the second embodiment based on the primary-side current are used as one power supply. It may be performed in the apparatus. For example, the determination based on the power factor and the determination based on the primary current may be performed twice. By doing so, it is possible to detect an abnormality related to charging and to detect a relative positional shift between the primary coil L1 and the secondary coil L2 with high accuracy by double check.

-Fourth modification:
In the first embodiment and the second embodiment, the charging control in steps S20, S80, S140, and S200 of the charging process is caused by a decrease in transmission efficiency due to the relative displacement between the primary coil L1 and the secondary coil L2. Therefore, it is preferable to suppress the primary side current and the secondary side current to be smaller than the charge control after step S250. In this way, when a decrease in transmission efficiency due to relative displacement between the primary coil L1 and the secondary coil L2 occurs, it is possible to prevent an unintended large primary current from flowing. Can do. For example, the charging circuit 230 of the battery system 200 may decrease the secondary current for a predetermined time (standby time) from the start of the charging process and increase the secondary current after the predetermined time has elapsed. Whether the control circuit 170 of the power supply apparatus 100 has experienced a decrease in transmission efficiency due to a relative displacement between the primary coil L1 and the secondary coil L2 within a predetermined time from the start of the charging process. It may be determined whether or not.

DESCRIPTION OF SYMBOLS 100, 100A ... Power supply device 110 ... Power supply 120 ... Primary side rectifier circuit 130 ... Inverter circuit 140 ... Current detector 150 ... Voltage detector 160 ... Primary side Resonant circuit 170, 170A ... Control circuit 180 ... Primary communication circuit 200 ... Battery system 210 ... Secondary resonance circuit 220 ... Secondary rectifier circuit 230 ... Charging circuit 240 ... Battery 250 ... Motor drive circuit 260 ... Motor 270 ... Secondary side communication circuit Cs, Cp, C1, C2 ... Capacitor L1, L2 ... Coil SW1, SW2, SW3 .. .Changeover switch

Claims (10)

A power supply device that supplies electric power for charging the battery in a non-contact manner using electromagnetic induction to a battery system including a secondary side resonance circuit including a secondary coil and a battery,
A primary side resonance circuit including a primary coil that generates a magnetic field for supplying AC power to the battery system via the secondary coil by electromagnetic induction;
Current detection means for detecting a primary current which is a current of the primary resonance circuit;
Voltage detecting means for detecting a primary side voltage which is a voltage of the primary side resonance circuit;
Power factor calculating means for calculating a power factor based on the primary current detected by the current detecting means and the primary voltage detected by the voltage detecting means;
At least one of a series resonant capacitor adjustment circuit and an inductance adjustment circuit in the primary side resonance circuit;
An inverter circuit for supplying the AC power to the primary side resonance circuit;
The power factor calculated by the power factor calculating means is compared with a threshold value corresponding to a target efficiency, and the power factor is increased when the power factor is lower than the threshold value. A characteristic that adjusts at least one of the capacitance of the resonance capacitor adjustment circuit, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary resonance circuit by the inverter circuit Adjusting means;
A power supply device comprising: The power supply device according to claim 1,
The characteristic adjusting unit is configured to be able to perform the adjustment over n stages (n is a natural number of 2 or more), and each time the adjustment is performed, the power factor is compared with the threshold value. And repeat the adjustment at most n times until the power factor is greater than or equal to the threshold value,
A power supply device that continues charging when the power factor becomes equal to or greater than the threshold value within n adjustments. The power supply device according to claim 2, further comprising:
A power supply apparatus comprising: a warning unit that warns a user when the power factor falls below the threshold value after performing the adjustment at the nth stage. The power supply device according to any one of claims 1 to 3, further comprising:
During charging, the power factor change amount monitored is continuously compared with a predetermined abnormality change amount. If the power factor change amount exceeds the abnormal change amount, an abnormality related to charging is detected. A power supply device comprising an abnormality detection means for determining that a problem has occurred. A power supply device that supplies electric power for charging the battery in a non-contact manner using electromagnetic induction to a battery system including a secondary side resonance circuit including a secondary coil and a battery,
A primary side resonance circuit including a primary coil that generates a magnetic field for supplying AC power to the battery system via the secondary coil by electromagnetic induction;
Current detection means for detecting a primary current which is a current of the primary resonance circuit;
At least one of a series resonant capacitor adjustment circuit and an inductance adjustment circuit in the primary side resonance circuit;
An inverter circuit for supplying the AC power to the primary side resonance circuit;
The primary current detected by the current detection means is compared with a threshold value that is larger than a target value, and when the primary current exceeds the threshold value, the primary current is The capacitance of the series resonance capacitor adjustment circuit, the inductance of the inductance adjustment circuit, and the frequency of the AC power supplied to the primary resonance circuit by the inverter circuit so as to approach the target value Characteristic adjusting means for adjusting at least one of them,
A power supply device comprising: The power supply device according to claim 5,
The characteristic adjusting means is configured to be able to perform the adjustment over n stages (n is a natural number of 2 or more), and each time the adjustment is performed in one stage, the primary current and the threshold value Making a comparison and repeating the adjustment at most n times until the primary current is below the threshold,
A power supply device that continues charging when the primary current becomes equal to or less than the threshold value within the n times of the adjustment. The power supply device according to claim 6, further comprising:
A power supply apparatus comprising: warning means for warning a user when the primary current exceeds the threshold value after performing the adjustment at the n-th stage. The power supply device according to any one of claims 1 to 7,
The series resonant capacitor adjustment circuit includes:
A standard capacitor;
One or more capacitance reducing capacitors arranged in series with the standard capacitor;
A capacitance reducing capacitor changeover switch for switching the capacitance reducing capacitor between an effective state and an invalid state;
Including
The adjustment by the characteristic adjusting means is performed by switching the capacitance reducing capacitor from the invalid state to the valid state by turning the capacitance reducing capacitor changeover switch from on to off. A power supply device including reducing the capacitance of the power supply. The power supply device according to any one of claims 1 to 8,
The inductance adjustment circuit is:
An inductance changeover switch for switching a part of the primary coil between an effective state and an invalid state;
The adjustment by the characteristic adjusting means is performed by switching a part of the primary coil from the valid state to the invalid state by turning the inductance changeover switch from off to on. A power supply device including reducing inductance. A power supply device according to any one of claims 1 to 9,
The adjustment by the characteristic adjusting means includes reducing the frequency of the AC power supplied to the primary resonance circuit by the inverter circuit.

Images