JP2015177578A - Equipment detection method for non-contact power supply device, and non-contact power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an equipment detection method for a non-contact power supply device with which electrical equipment can be detected with high precision without being affected by noise, and a non-contact power supply device.SOLUTION: A system controller 12 supplies high-frequency current of a detection frequency from a half bridge circuit 22 to a primary coil L1 in order to detect mounting or non-mounting of equipment and metal. The system controller 12 obtains an output voltage Vs relative to primary current flowing in the primary coil L1 just after the current supply of the high-frequency current of the detection frequency is stopped, and specifies the mounting or non-mounting of the equipment and the metal on the basis of the obtained output voltage Vs.

Description

  The present invention relates to a device detection method for a non-contact power supply apparatus and a non-contact power supply apparatus.

  Conventionally, an electromagnetic induction type non-contact power feeding device detects that an electric device is placed on a placement surface on which a primary coil is arranged, and supplies a high-frequency current to the primary coil to generate electricity by electromagnetic induction. Secondary power is generated in a secondary coil of a power receiving device provided in the device.

  Various detection methods have been proposed for detecting whether or not an electrical device is placed on a placement surface on which a primary coil is placed. For example, in Patent Document 1, paying attention to the fact that the self-inductance of the primary coil changes as the electrical equipment approaches the non-contact power feeding device, the electrical equipment detects the voltage at the end of the primary coil during energization. It is detected whether the primary coil has been approached.

Japanese Patent No. 469430

  By the way, in an electromagnetic induction type non-contact power supply device, in order to improve the power supply capability and increase the output power to the electrical equipment, the drive voltage of the power supply circuit (inverter) that generates a high-frequency current to be supplied to the primary coil is used. Raising is done. As a result, there arises a problem that large switching noise occurs during operation due to an increase in the driving voltage of the power feeding circuit (inverter).

  Accordingly, when the voltage at the primary coil end that is energized is detected as in the detection method of Patent Document 1, the voltage generated at the primary coil end includes a large amount of switching noise. High detection cannot be expected. Moreover, since the primary current of the primary coil also increases, a filter circuit or the like must be provided in order to maintain the detection capability, and there is a problem that the circuit becomes large-scale.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a device detection method and a non-contact power supply device that can detect electrical devices with high accuracy without being affected by noise. It is in providing a contact electric power feeder.

  An apparatus detection method for a non-contact power supply apparatus for solving the above-described problem is that when an electric apparatus is disposed in a primary coil that generates an alternating magnetic field when a high-frequency current having a power supply frequency is applied, the primary coil is A device detection method for a non-contact power feeding device that generates an alternating magnetic field and generates secondary power in a secondary coil of a power receiving device provided in the electrical device by electromagnetic induction, the device detecting the primary coil Immediately after the high frequency current of the frequency for use is energized and immediately after the energization of the high frequency current of the frequency for detection to the primary coil is stopped, an inductance component, capacitance component, resistance component such as wiring resistance or internal resistance, etc. The relative voltage relative to the primary current flowing through the primary coil that is attenuated by the determined transient characteristics is detected as a detection voltage, and the presence or absence of an electrical device is specified by the detection voltage. The features.

  Further, in the above configuration, immediately after the energization is stopped, the electrical device is operated under a condition that the electrical device is not disposed from the energization stop of the high-frequency current having the detection frequency to the primary coil. It is preferable that it is a time before reaching a reference voltage that specifies that the electric device is arranged when it is arranged.

  In the non-contact power feeding apparatus for solving the above-described problem, when an electric device is arranged in a primary coil that generates an alternating magnetic field when a high-frequency current having a feeding frequency is applied, the primary coil generates the alternating magnetic field. A non-contact power feeding device that generates secondary power in a secondary coil of a power receiving device provided in the electric device by electromagnetic induction, and generates a high-frequency current having a detection frequency in the primary coil. Immediately after the energization of the high-frequency current generating means to be energized and the high-frequency current of the detection frequency to the primary coil is stopped, it is determined by the resistance component such as the inductance component, capacitance component, wiring resistance and internal resistance on the non-contact power feeding device side Detecting means for detecting, as a detection voltage, a relative voltage relative to the primary current flowing through the primary coil that is attenuated due to transient characteristics; and based on the detection voltage detected by the detecting means. Wherein the electrical device to the primary coil had a specifying means for specifying whether disposed.

  Further, in the above configuration, immediately after the energization is stopped, the electrical device is operated under a condition that the electrical device is not disposed from the energization stop of the high-frequency current having the detection frequency to the primary coil. It is preferable that it is a time before reaching a reference voltage that specifies that the electric device is arranged when it is arranged.

  Further, in the above configuration, the high-frequency current generation means energizes the primary coil intermittently with the high-frequency current having the detection frequency a plurality of times, and the detection means detects the detection voltage immediately after the stop every time the energization is stopped. Preferably, the specifying unit specifies whether or not the electric device is arranged in the primary coil based on an average value of the detected plurality of detection voltages.

  Further, in the above configuration, the detection means detects a plurality of detection voltages immediately after stopping energization in a time series, and the specifying means is based on an average value of the plurality of detection voltages detected in the time series. It is preferable to specify whether or not the electrical device is arranged in the primary coil.

  Further, in the above configuration, during the energization of the high frequency current of the detection frequency to the primary coil, the transient characteristics determined by the resistance component such as the inductance component, the capacitance component, the wiring resistance and the internal resistance on the non-contact power feeding device side. A second detection unit configured to detect, as a second detection voltage, a relative voltage obtained by sampling a plurality of relative voltages relative to the primary current flowing through the primary coil to be saturated; Whether or not the electrical device is arranged in the primary coil based on an average value of the plurality of second detection voltages when the noise level is obtained based on the second detection voltages and the noise level is low The electrical device is arranged in the primary coil based on a detected voltage immediately after the energization stop detected by the detecting means when the noise level is specified It is preferable to identify how.

  According to the present invention, it is possible to detect an electric device with high accuracy without being affected by noise.

The whole perspective view showing the non-contact electric supply device and electric equipment for explaining an embodiment. Similarly, explanatory drawing which shows the arrangement | sequence state of the primary coil provided in the electric power feeding area. Similarly, the electrical block circuit diagram of a non-contact electric power feeder and an electric equipment. Similarly, the electric block circuit diagram of the receiving device of an electric equipment. Similarly, the electric block circuit diagram for demonstrating a basic electric power feeding unit circuit. Similarly, the electrical circuit diagram for demonstrating a half-bridge circuit. Similarly, each signal waveform diagram for demonstrating operation | movement of a basic electric power feeding unit circuit. Similarly, the characteristic view which shows the output with respect to the frequency for demonstrating the frequency for a detection. Similarly, the waveform diagram explaining each area | region of the waveform of an output voltage. The signal waveform diagram for demonstrating another example of a non-contact electric power feeder. The wave form diagram of the output voltage for demonstrating another example of a non-contact electric power feeder. The wave form diagram of the output voltage for demonstrating another example of a non-contact electric power feeder.

Embodiments of a non-contact power feeding apparatus embodying the present invention will be described below with reference to the drawings.
FIG. 1 is an overall perspective view of a non-contact power supply device (hereinafter referred to as a power supply device) 1 and an electric device (hereinafter referred to as a device) E that is supplied with non-contact power from the power supply device 1.

  The power feeding device 1 includes a rectangular plate-shaped housing 2, and the upper surface thereof is a flat surface and forms a placement surface 3 on which the device E is placed. The mounting surface 3 is divided into a plurality of rectangular power supply areas AR, and in this embodiment, 24 are arranged in a row in the left-right direction (horizontal direction) and 6 in the vertical direction (vertical direction). A power feeding area AR is defined.

  As shown in FIG. 2, a primary coil L <b> 1 wound in a rectangular shape in accordance with the outer shape of the power supply area AR is provided in the housing 2 at a position corresponding to each partitioned power supply area AR. Has been placed. The primary coil L1 of each power supply area AR is connected to each basic power supply unit circuit 21 (see FIG. 3) provided in the housing 2 for each power supply area AR.

  The primary coil L1 of each power supply area AR is radiated with an alternating magnetic field when a high-frequency power having a power supply frequency fp is energized by the corresponding basic power supply unit circuit 21. Each primary coil L1 is energized alone or in cooperation with another primary coil L1, and is wound into a quadrangular shape built in the device E placed on the placement surface 3. Non-contact power feeding is performed to the coil L2. That is, when the device E is mounted on the mounting surface 3 of the housing 2, the secondary coil L2 of the device E is induced based on electromagnetic induction by an alternating magnetic field of the feeding frequency fp radiated from the primary coil L1. Electric power (secondary power) is generated.

  Here, the power supply frequency fp is the resonance frequency determined by the inductance component and the capacitance component on the device E side when the device E is placed in the power supply area AR. Therefore, by energizing the primary coil L1 at the power supply frequency fp determined by the inductance component and the capacitance component on the device E side, the power supplied from the primary coil L1 on the device E side can be received with low loss.

  Each primary coil L1 is supplied with a high-frequency current having a detection frequency fs in addition to a high-frequency current having a power supply frequency fp. The high frequency current of the detection frequency fs is energized to the primary coil L1 in order to detect whether or not the device E is placed in the power supply area AR (primary coil L1). The detection frequency fs is set as follows.

  As shown in FIG. 8, the first resonance characteristic A1 is a primary composed of a series circuit of a primary coil L1 and a primary side resonance capacitor C1 (see FIG. 3) when nothing is placed in the power supply area AR. The output of the primary coil L1 with respect to the frequency in a circuit is shown. That is, the first resonance characteristic A1 indicates the output of the primary coil L1 with respect to the frequency determined by the inductance component and the capacitance component on the power feeding device 1 side when nothing is placed in the power feeding area AR.

  The second resonance characteristic A2 indicates the output of the primary coil L1 with respect to the frequency determined by the inductance component and the capacitance component on the power feeding device 1 side when the metal M (see FIG. 1) is placed in the power feeding area AR.

  Further, the third resonance characteristic A3 indicates the output of the primary coil L1 with respect to the frequency determined by the inductance component and the capacitance component on the power feeding device 1 side when the device E is placed in the power feeding area AR.

  The first to third resonance characteristics A1 to A3 are required in advance through experiments, tests, and the like to increase the resonance frequency in the order of the third resonance characteristic A3, the first resonance characteristic A1, and the second resonance characteristic A2. ing. Moreover, these frequency bands are very adjacent because the first resonance characteristic A1 is based on the variation in inductance caused by the metal M or the device E.

  Here, as shown in FIG. 8, when nothing is placed in the power supply area AR while the primary coil L1 is energized at the specific frequency fk of the first resonance characteristic A1 (frequency higher than the resonance frequency fr). The inductance component of the primary circuit does not change. For this reason, the resonance characteristic remains unchanged at the first resonance characteristic A1, and therefore the output for the specific frequency fk appearing in the primary coil L1 becomes the intermediate value Vmid.

  Further, when the metal M is placed in the power feeding area AR while the primary coil L1 is energized at the specific frequency fk of the first resonance characteristic A1, the metal M on which the inductance component of the primary circuit is placed. Change. As a result, the resonance characteristic shifts from the first resonance characteristic A1 to the second resonance characteristic A2. As a result, the output for the specific frequency fk appearing in the primary coil L1 becomes the maximum value Vmax as shown in FIG.

  Further, when the device E is placed in the power feeding area AR while the primary coil L1 is energized at the specific frequency fk of the first resonance characteristic A1, the device E on which the inductance component of the primary circuit is placed. Change. As a result, the resonance characteristic shifts from the first resonance characteristic A1 to the third resonance characteristic A3. As a result, the output for the specific frequency fk appearing in the primary coil L1 becomes the minimum value Vmin as shown in FIG.

  Accordingly, the primary coil L1 is energized with the specific frequency fk in the first resonance characteristic A1 as the detection frequency fs for device detection. It can be seen that the presence or absence of the device E and the presence or absence of the metal M on the power supply area AR can be detected by knowing the output value (output voltage Vs) with respect to the detection frequency fs appearing in the primary coil L1.

That is, when the output voltage Vs for the detection frequency fs appearing in the primary coil L1 is equal to or higher than the maximum value Vmax, it can be seen that the metal M on the power supply area AR is placed.
Further, when the output voltage Vs corresponding to the detection frequency fs appearing in the primary coil L1 is equal to or less than the minimum value Vmin, it can be seen that the device E on the power supply area AR is placed.

  Furthermore, when the output voltage Vs for the detection frequency fs appearing in the primary coil L1 is between the minimum value Vmin and the minimum value Vmin, it can be seen that the device E on the power supply area AR is not placed.

In this embodiment, the detection frequency fs, the maximum value Vmax, and the minimum value Vmin are obtained in advance through tests, experiments, calculations, or the like.
The detection frequency fs is set such that when the metal M is placed on the primary coil L1, the output with respect to the frequency at the first resonance characteristic A1 is increased regardless of the position, size, etc. of the metal M. The frequency is set. The detection frequency fs is set such that when the device E is placed on the primary coil L1, the output with respect to the frequency at the first resonance characteristic A1 becomes small regardless of the position, size, etc. of the device E. The frequency is set.

  When it is determined that the device E is placed in the power feeding area AR, the primary coil L1 is energized with a high-frequency current having a power feeding frequency fp. The power feeding frequency fp is a resonance frequency determined by the inductance component and the capacitance component on the device E side as described above.

The power supply frequency fp when power is supplied for power supply is set such that the interval with the detection frequency fs is as follows.
The fourth resonance characteristic A4 shown in FIG. 8 is a resonance characteristic that has a maximum output at the power feeding frequency fp, and in the device E facing the primary coil L1 when the device E is placed in the power feeding area AR. The output of the primary coil L1 with respect to the frequency in the said secondary circuit is shown. In the fourth resonance characteristic A4, the output with respect to the detection frequency fs appearing in the primary coil L1 is a voltage value Vn smaller than the minimum value Vmin and close to 0 volts, as shown in FIG. This is because the voltage value Vn decreases as the interval between the power supply frequency fp and the detection frequency fs increases.

  Accordingly, it is assumed that there is a power feeding area AR in which the primary coil L1 is energized and fed at the power feeding frequency fp of the fourth resonance characteristic A4. When the adjacent power supply area AR detects the device by energizing the primary coil L1 at the detection frequency fs, the voltage value Vn is small, and therefore the primary coil L1 is energized at the power supply frequency fp. The influence from the feeding area AR that feeds power is small.

  Here, the width of the maximum value Vmax and the minimum value Vmin is W1 (= Vmax−Vmin), and the width of the voltage value Vn and the 0 volt at the detection frequency fs of the fourth resonance characteristic A4 is W2 (= Vn-0). At this time, W1> W2.

  Accordingly, it is assumed that there is a power feeding area AR in which the primary coil L1 is energized and fed at the power feeding frequency fp of the fourth resonance characteristic A4. When the adjacent power supply area AR detects the device by energizing the primary coil L1 at the detection frequency fs, since W1> W2, the primary coil L1 is energized at the power supply frequency fp. The influence from the feeding area AR that feeds power is small.

  That is, in the resonance circuit determined by the inductance component and the capacitance component on the device E side, the resonance having the fourth resonance characteristic A4 shown in FIG. 8 is such that the interval between the power supply frequency fp and the detection frequency fs satisfies W1> W2. Set to circuit.

Incidentally, in the present embodiment, the detection frequency fs is set around 70 kHz, and the power feeding frequency fp is set around 140 kHz.
Next, the electrical configuration of the power feeding device 1 and the device E will be described with reference to FIG.

(Equipment E)
First, the device E will be described. In FIG. 3, the device E includes a power receiving circuit 5 as a power receiving device that receives secondary power from the power feeding device 1 and a load Z.

The power receiving circuit 5 includes a rectifier circuit 6 and a communication circuit 7 as shown in FIG.
The rectifier circuit 6 is connected to a series circuit of a secondary coil L2 and a secondary side resonance capacitor C2 constituting a secondary circuit on the device E side. The secondary coil L2 generates secondary power based on the alternating magnetic field radiated from the primary coil L1, and outputs the secondary power to the rectifier circuit 6.

  The rectifying circuit 6 converts the secondary power generated in the secondary coil L2 by electromagnetic induction by excitation of the primary coil L1 into a DC voltage. The rectifier circuit 6 supplies the converted DC voltage to the load Z of the device E.

  The DC voltage converted by the rectifier circuit 6 is also used as a drive source for the communication circuit 7. The communication circuit 7 is a circuit that generates a device authentication signal ID and a power supply request signal RQ and transmits the device authentication signal ID and the power supply request signal RQ to the power supply apparatus 1 through the secondary coil L2. The device authentication signal ID is an authentication signal indicating that the device E can receive power from the power supply device 1 with respect to the power supply device 1. The power supply request signal RQ is a request signal for requesting the power supply apparatus 1 to supply power.

  The device authentication signal ID and the power supply request signal RQ are binarized (high level / low level) signals composed of a plurality of bits, and the binarized signals are converted into a secondary resonance capacitor C2 and a rectifier circuit 6. Is output to the receiving wire that connects to. When a binarized signal is output to the receiving wire, the amplitude of the secondary current flowing through the secondary coil L2 by electromagnetic induction by energization of the primary coil L1 that is driven and excited at the power supply frequency fp is 2 It changes corresponding to the quantified signal.

  The magnetic flux radiated from the secondary coil L2 is changed by the change in the amplitude of the secondary current at the power supply frequency fp, and the changed magnetic flux propagates as electromagnetic induction to the primary coil L1 and flows through the primary coil L1. Change the amplitude of the current.

  That is, the secondary current of the power feeding frequency fp flowing between both terminals of the secondary coil L2 is amplitude-modulated by the binarized signals (device authentication signal ID and power feed request signal RQ). Then, the magnetic flux of the secondary current having the amplitude-modulated power supply frequency fp is propagated as a transmission signal to the primary coil L1.

(Power supply device 1)
Next, the power feeding device 1 will be described. As illustrated in FIG. 3, the power feeding device 1 includes a basic unit unit 20 including a common unit unit 10 and a basic power feeding unit circuit 21 provided for each of the 24 primary coils L1.

(Common unit 10)
The common unit unit 10 includes a power supply circuit 11, a system control unit 12 that performs overall control of the basic unit unit 20, and a memory 13 that stores various data.

  The power supply circuit 11 includes a rectifier circuit and a DC / DC converter, and receives a commercial power supply from the outside and rectifies the rectifier circuit. The power supply circuit 11 converts the rectified DC voltage into a desired voltage by a DC / DC converter, and then outputs the DC voltage Vdd to the system control unit 12, the memory 13, and the basic unit unit 20 as a driving power supply.

  The system control unit 12 includes a microcomputer and controls the basic unit unit 20. That is, the system control unit 12 controls the basic power supply unit circuit 21 provided for each of the 24 primary coils L1 in accordance with a microcomputer control program.

The system control unit 12 has a device detection mode, a power supply mode, and a sleep mode that are executed for the basic power supply unit circuit 21 in each power supply area AR.
In the device detection mode, the system control unit 12 stops energization after energizing the primary coil L1 of each basic power supply unit circuit 21 with the high-frequency current of the detection frequency fs for a certain period. And the system control part 12 acquires the relative voltage (output voltage Vs) relative to the primary current which flows into the primary coil L1 immediately after the energization stop, and the apparatus E and the metal M based on each acquired relative voltage. In this mode, the presence / absence of the presence or absence is detected.

  In the power supply mode, for the basic power supply unit circuit 21 in the power supply area AR that the system control unit 12 specifies that the device E is placed in the device detection mode processing, the basic power supply unit circuit 21 is controlled to be in a power supply state. It is a mode to do.

  In the rest mode, the basic control unit circuit 21 is controlled to be in a rest state for the basic power supply unit circuit 21 in the power supply area AR that the system control unit 12 has determined that the metal M is placed in the device detection mode process. It is a mode to do.

  The memory 13 is a nonvolatile memory, and stores various data used when the system control unit 12 performs various processing operations. The memory 13 is assigned a storage area for each of the 24 power supply areas AR, and information on the current power supply area AR is stored in the assigned storage area.

(Basic unit 20)
As shown in FIG. 3, the basic unit section 20 includes a plurality (24) of basic power supply unit circuits 21 provided for each power supply area AR (each primary coil L <b> 1). Each basic power supply unit circuit 21 exchanges data with the system control unit 12 and is controlled by the system control unit 12.

Since each basic power supply unit circuit 21 has the same circuit configuration, one basic power supply unit circuit 21 will be described with reference to FIG.
(Basic power supply unit circuit 21)
As shown in FIG. 5, the basic power supply unit circuit 21 includes a half bridge circuit 22, a drive circuit 23, a current detection circuit 24, an output detection circuit 25, and a signal extraction circuit 26.

(Half bridge circuit 22)
As shown in FIG. 6, the half-bridge circuit 22 is a known half-bridge circuit. The half-bridge circuit 22 includes a voltage dividing circuit in which a first capacitor Ca and a second capacitor Cb are connected in series, and a series in which a first power transistor Qa and a second power transistor Qb are connected in series to the voltage dividing circuit. The drive circuit which consists of a circuit is connected in parallel. In the present embodiment, the first and second power transistors Qa and Qb are configured by N-channel MOSFETs.

  And the primary circuit which comprises the primary circuit by the side of the electric power feeder 1 between the connection point N1 of the 1st capacitor | condenser Ca and the 2nd capacitor | condenser Cb, and the connection point N2 of the 1st power transistor Qa and the 2nd power transistor Qb. A series circuit of the coil L1 and the primary side resonance capacitor C1 is connected.

  As shown in FIG. 7, drive signals PSa and PSb are input from the drive circuit 23 to the gate terminals of the first power transistor Qa and the second power transistor Qb. The first and second power transistors Qa and Qb are alternately turned on and off based on drive signals PSa and PSb respectively input to their gate terminals. As a result, a high-frequency current that energizes the primary coil L1 is generated. The primary coil L1 generates an alternating magnetic field when this high-frequency current is applied.

(Drive circuit 23)
The drive circuit 23 receives a control signal CT that controls the frequency of the high-frequency current that flows in the primary coil L1 from the system control unit 12, and outputs the drive signal PSa to the gate terminals of the first and second power transistors Qa and Qb, respectively. , PSb. That is, as shown in FIG. 7, the drive circuit 23 alternately turns on and off the first and second power transistors Qa and Qb based on the control signal CT to set the frequency of the high-frequency current that flows through the primary coil L1. Drive signals PSa and PSb are generated.

  As shown in FIG. 7, the drive signals PSa and PSb have a dead time so that the first power transistor Qa and the second power transistor Qb are not turned on simultaneously. The second power transistor Qb has the same off time and on time, and the first power transistor Qa has a shorter on time and a correspondingly longer off time.

Here, the control signal CT from the system control unit 12 is a data signal that determines the frequency of the high-frequency current that energizes the primary coil L1.
In the device detection mode, the system control unit 12 outputs a control signal CT for energizing the primary coil L1 with a high-frequency current having a detection frequency fs for device detection. Therefore, in the device detection mode, the 24 basic power supply unit circuits 21 (drive circuits 23) each output the control signal CT of the detection frequency fs for device detection from the system control unit 12.

  On the other hand, in the power supply mode, the system control unit 12 outputs a control signal CT for energizing the primary coil L1 with a high-frequency current having a power supply frequency fp for power supply. Therefore, in the power supply mode, the 24 basic power supply unit circuits 21 (drive circuits 23) each output the control signal CT of the power supply frequency fp for power supply from the system control unit 12.

(Current detection circuit 24)
The current detection circuit 24 is provided between one terminal of the primary coil L1 and the half-bridge circuit 22, detects the primary current at that time flowing through the primary coil L1, and outputs it as a current detection signal SG1. That is, when the drive signals PSa and PSb shown in FIG. 7 are output, the current detection circuit 24 outputs the current detection signal SG1 shown in FIG.

(Output detection circuit 25)
The output detection circuit 25 is connected to the current detection circuit 24. The output detection circuit 25 receives the current detection signal SG1 detected by the current detection circuit 24, converts it to an output voltage relative to the current detection signal SG1, converts it to a digital value, and outputs it. The output detection circuit 25 includes an envelope detection circuit, and detects the current detection signal SG1 of the current detection circuit 24 using the envelope detection circuit. That is, the output detection circuit 25 (envelope detection circuit) generates an envelope waveform signal (output voltage Vs) shown in FIG. 7 that wraps the outside of the current detection signal SG1 from the current detection signal SG1.

  The output detection circuit 25 includes an AD converter that converts an analog value into a digital value, and converts the output voltage Vs at that time into a digital value. The output detection circuit 25 acquires the digital value of the output voltage Vs at that time in response to the sampling signal SP from the system control unit 12 and outputs the digital value to the system control unit 12.

  Here, the sampling signal SP from the system control unit 12 to the output detection circuit 25 of each basic power supply unit circuit 21 outputs the sampling signal SP immediately after the control signal CT disappears to each output detection circuit 25, respectively. It is supposed to be. That is, the timing at which the system control unit 12 acquires the digital value of the output voltage Vs of each output detection circuit 25 is set immediately after the energization of the high-frequency current having the detection frequency fs to the primary coil L1 is stopped. . In other words, the digital value of the output voltage Vs when the energization of the high-frequency current of the detection frequency fs is stopped and the output voltage Vs starts to fall toward zero volts as shown in FIG. 7 is acquired.

  More specifically, as shown in FIG. 9, when the energization of the high-frequency current having the detection frequency fs is started, the waveform of the output voltage Vs rises from zero volts and enters the saturation region Z2 through the unsaturated region Z1. When the energization is stopped, the output voltage Vs becomes an attenuation region Z3 in which the waveform immediately attenuates from the saturation region Z2 toward zero volts.

  Regarding the transition of the output voltage Vs, when the waveform is in the unsaturated region Z1 and the saturated region Z2, it is a waveform when a high-frequency current of the detection frequency fs is energized to the primary coil L1. That is, it is a waveform when the half-bridge circuit 22 performs a switching operation to generate a high-frequency current having a detection frequency fs and the high-frequency current is passed through the primary coil L1.

  Therefore, switching noise resulting from the switching operation of the half-bridge circuit 22 is included in the high-frequency current and appears in the waveform of the output voltage Vs in the unsaturated region Z1 and the saturated region Z2.

  In contrast, the waveform in the attenuation region Z3 is a waveform when the high-frequency current having the detection frequency fs is not supplied to the primary coil L1. That is, this is a waveform when the half-bridge circuit 22 stops the switching operation and does not generate the high-frequency current having the detection frequency fs and the primary coil L1 is de-energized. In other words, the waveform is attenuated by a transient characteristic determined by a resistance component such as an inductance component and a capacitance component on the power feeding device 1 side, and further a wiring resistance, an inductance component, and an internal resistance of the capacitance component.

Therefore, noise due to the switching operation of the half bridge circuit 22 does not appear in the waveform of the output voltage Vs in the attenuation region Z3.
Therefore, in the present embodiment, the acquisition timing is determined as the timing at which the output voltage Vs is acquired in the attenuation region Z3 without the switching noise of the half bridge circuit 22. Accordingly, the system control unit 12 immediately outputs the control signal CT for generating the detection frequency fs for each drive circuit 23 (immediately after the primary coil L1 is de-energized) and outputs the corresponding output detection circuit to the sampling signal SP. 25, respectively. As a result, the system control unit 12 can input a digital value of the output voltage Vs without switching noise.

  Here, the reason why the acquisition timing is immediately after de-energization is that, in the attenuation region Z3, the output voltage Vs drops below the minimum value Vmin for device detection even when the device E is not placed over time. It is. Similarly, in the attenuation region Z3, the output voltage Vs drops below the maximum value Vmax for detecting the presence or absence of the device E even when the metal M is placed over time.

  Therefore, the acquisition timing is such that the output voltage Vs does not become the minimum value Vmin or less from the disappearance of the control signal CT under the condition where the device E is not placed, and the control signal CT is disappeared under the condition where the metal M is placed. This is the timing at which the output voltage Vs does not become less than the maximum value Vmax. This acquisition timing is obtained in advance through tests, experiments, calculations, or the like.

And the system control part 12 specifies the presence or absence of the metal M and the presence or absence of the apparatus E based on the acquired digital value of the output voltage Vs of each output detection circuit 25. FIG.
The system control unit 12 specifies that the metal M is placed when the output voltage Vs (digital value) is equal to or higher than the maximum value Vmax, and the device E is mounted when the output voltage Vs is equal to or lower than the minimum value Vmin. Is identified. Further, the system control unit 12 specifies that the device E is placed when the output voltage Vs is between the maximum value Vmax and the minimum value Vmin.

(Signal extraction circuit 26)
The signal extraction circuit 26 is connected to the current detection circuit 24. The signal extraction circuit 26 inputs the primary current (current detection signal SG1) of the primary coil L1 at that time from the current detection circuit 24 while the primary coil L1 is energized at the power supply frequency fp. The signal extraction circuit 26 inputs the amplitude-modulated transmission signal transmitted from the secondary coil L <b> 2 of the device E placed on the placement surface 3 via the current detection circuit 24.

  The signal extraction circuit 26 extracts the device authentication signal ID and the power supply request signal RQ from the input transmission signal. The signal extraction circuit 26 outputs the permission signal EN to the system control unit 12 when extracting both the device authentication signal ID and the power supply request signal RQ from the transmission signal. Incidentally, the signal extraction circuit 26 does not output the permission signal EN to the system control unit 12 when only one of the device authentication signal ID and the power supply request signal RQ is extracted or when neither signal is extracted. .

Next, the operation of the non-contact power feeding device 1 configured as described above will be described.
(Device detection mode)
Now, the basic power supply unit circuits 21 of the 24 power supply areas AR (primary coils L1) are sequentially accessed by the system control unit 12 for a certain period, and this is repeated.

At this time, first, the system control unit 12 outputs a control signal CT for device detection to the drive circuit 23 of the basic power supply unit circuit 21 provided in the first power supply area AR.
At this time, the system control unit 12 outputs the control signal CT of the detection frequency fs for a predetermined time to the drive circuit 23 of the basic power supply unit circuit 21 in the first power supply area AR stored in the memory 13. In response to the control signal CT, the drive circuit 23 energizes the primary coil L1 at the detection frequency fs for a predetermined time.

  Subsequently, the system control unit 12 outputs the sampling signal SP after a predetermined time has elapsed, that is, immediately after the energization of the primary coil L1 by the high-frequency current having the detection frequency fs is stopped. The system control unit 12 inputs the output voltage Vs (digital value) of the first power feeding area AR output from the output detection circuit 25 in response to the sampling signal SP, and stores it in the storage area assigned to the memory 13. That is, the system control unit 12 inputs the output voltage Vs (digital value) of the attenuation region Z3 that does not include switching noise.

  Next, the system control unit 12 specifies device detection based on the output voltage Vs (digital value). The identification is performed by comparing the output voltage Vs with the maximum value Vmax and the minimum value Vmin. When there is nothing in the first power supply area AR, the output voltage Vs is between the maximum value Vmax and the minimum value Vmin. Further, when the device E is present in the first power supply area AR, the output voltage Vs is equal to or lower than the minimum value Vmin. When the metal M is present in the first power supply area AR, the output voltage Vs is equal to or higher than the maximum value Vmax.

And if it specifies that there is nothing in the electric power feeding area AR, the system control part 12 will move to the apparatus detection of the 2nd electric power feeding area AR.
Note that the system control unit 12 displays the device detection detection result of the first power supply area AR as the first power supply area AR of the memory 13 before moving to control of the basic power supply unit circuit 21 of the second power supply area AR. Is stored in the storage area allocated to.

  Thereafter, the basic power supply unit circuit 21 in the 24th power supply area AR is similarly controlled in order, and device detection is performed. If the devices E are not placed in all the power supply areas AR, the system control unit 12 proceeds to the second round of control, and again controls the basic power supply unit circuit 21 in the first power supply area AR. Move on.

  On the other hand, in a certain power supply area AR, the system control unit 12 specifies that the device E is placed in the power supply area AR when the output voltage Vs is equal to or lower than the minimum value Vmin. And the system control part 12 performs electric power feeding mode about the basic electric power feeding unit circuit 21 of the said electric power feeding area AR.

(Power supply mode)
When the system control unit 12 specifies that the device E is placed in the power supply area AR based on the output voltage Vs, the system control unit 12 supplies power to the drive circuit 23 of the corresponding basic power supply unit circuit 21 at the power supply frequency fp. Control signal CT is output. The drive circuit 23 energizes the primary coil L1 at the power supply frequency fp in response to the control signal CT for the power supply frequency fp.

When the primary coil L1 is energized at the power feeding frequency fp, the magnetic flux propagates to the device E placed on the power feeding area AR.
At this time, resonance occurs between the secondary coils L2 of the device E placed on the power supply area AR, and the device E receives highly efficient power supply. Based on this high DC voltage, the communication circuit 7 of the device E operates and outputs a binarized signal (device authentication signal ID and power supply request signal RQ). As a result, the secondary current of the power feeding frequency fp flowing between both terminals of the secondary coil L2 is amplitude-modulated, and the magnetic flux of the secondary current of the amplitude-modulated power feeding frequency fp is transmitted to the primary coil L1 as a transmission signal. Propagated.

  The signal extraction circuit 26 inputs the transmission signal subjected to amplitude modulation via the current detection circuit 24. The signal extraction circuit 26 determines whether the input transmission signal includes a device authentication signal ID and a power supply request signal RQ. The signal extraction circuit 26 outputs the permission signal EN to the system control unit 12 when there is the device authentication signal ID and the power supply request signal RQ. In response to the permission signal EN, the system control unit 12 outputs a control signal CT for the power supply frequency fp to the drive circuit 23. The drive circuit 23 energizes the primary coil L1 at the power supply frequency fp in response to the control signal CT for the power supply frequency fp. Accordingly, the device E receives power.

  Then, the system control unit 12 confirms the device authentication signal ID and the like (permission signal EN) from the device E, and continues energization to the primary coil L1 of the basic power supply unit circuit 21 to the next power supply area. Control proceeds to the basic power supply unit circuit 21 of the AR.

  Note that the system control unit 12 indicates information indicating that the device E is placed in the power supply area AR and is supplying power before the control of the basic power supply unit circuit 21 in the next power supply area AR. Store in the storage area allocated to the area AR. As a result, when control of the power supply area AR is next performed, the system control unit 12 continues the power supply mode instead of the device detection mode for the power supply area AR and places the device E placed in the power supply area AR. Continue to supply power.

  Incidentally, when the power supply of the basic power supply unit circuit 21 is continued, when the device authentication signal ID or the like (permission signal EN) from the device E disappears, the system control unit 12 Stop energization for power supply.

  That is, the signal extraction circuit 26 does not output the permission signal EN to the system control unit 12 when there is no device authentication signal ID or power supply request signal RQ or when there is neither. Based on the absence of the enable signal EN, the system control unit 12 loses the control signal CT for the power supply frequency fp to the drive circuit 23. The drive circuit 23 stops energization for power supply of the primary coil L1 at the power supply frequency fp based on the disappearance of the control signal CT for the power supply frequency fp.

  The power supply area AR is a target of the device detection mode, and the primary coil L1 is energized with the high-frequency current of the detection frequency fs in the above-described order, and the presence of the metal M and the presence of the device E are specified. .

  On the other hand, in a certain power supply area AR, the system control unit 12 specifies that the metal M is placed in the power supply area AR when the output voltage Vs is greater than or equal to the maximum value Vmax. Then, the system control unit 12 executes the sleep mode for the basic power supply unit circuit 21 in the power supply area AR.

(Pause mode)
When the system control unit 12 specifies that the metal M is placed in the power supply area AR based on the output voltage Vs, the system control unit 12 does not output the control signal CT to the drive circuit 23 of the corresponding basic power supply unit circuit 21. The power supply area AR is put into a dormant state. Then, the system control unit 12 proceeds to control of the basic power supply unit circuit 21 in the next power supply area AR.

  In addition, before the system control unit 12 shifts to control of the basic power supply unit circuit 21 in the next power supply area AR, the power supply area AR indicates information indicating that the metal M has been detected in the previous device detection. It memorize | stores in the memory area allocated to the said electric power feeding area AR. Then, the system control unit 12 prepares for the next control.

  Then, the system control unit 12 performs a predetermined time (predetermined number of times of circulation) from the detection of the first metal M for the power supply area AR in the dormant state based on the information on which the metal M is placed. The device detection mode is executed again.

Next, effects of the embodiment configured as described above will be described below.
(1) According to the above embodiment, the system control unit 12 acquires the output voltage Vs relative to the primary current flowing in the primary coil L1 immediately after the energization of the high-frequency current having the detection frequency fs is stopped. And the presence or absence of mounting | wearing of the apparatus E and the metal M was specified with the acquired output voltage Vs.

  Therefore, the output voltage Vs acquired immediately after the energization is stopped is a voltage after the half bridge circuit 22 finishes the switching operation, and is acquired from a voltage waveform that does not include the switching noise of the half bridge circuit 22.

As a result, it is possible to accurately determine whether the device E and the metal M are placed in the power supply area AR without providing a noise removal filter.
Moreover, in order to increase the output power to the device E, even if the switching noise increases by increasing the DC voltage Vdd applied to the half bridge circuit 22, it is not affected by the noise and can be accurately specified. can do.

  (2) According to the above embodiment, since the output voltage Vs relative to the primary current flowing in the primary coil L1 immediately after the energization of the high-frequency current of the detection frequency fs is stopped is obtained, a special circuit is provided. There is no need to provide it, and it can be realized with a simple circuit configuration.

In addition, you may change the said embodiment as follows.
In the above embodiment, when detecting devices for each power supply area AR, a high-frequency current having a detection frequency fs is applied to each primary coil L1 once, and the output voltage Vs immediately after the one-time power supply stop is acquired. , Whether or not the device E is mounted. As shown in FIG. 10, a high-frequency current having a detection frequency fs is intermittently continuously supplied to a single primary coil L1 a plurality of times (three times in FIG. 10). The output detection circuit 25 acquires a plurality of output voltages Vs immediately after the energization is stopped. The output detection circuit 25 obtains an average value of the plurality of acquired output voltages Vs and outputs the average value to the system control unit 12.

  The system control unit 12 compares the acquired average value of the plurality of output voltages Vs with the minimum value Vmin and the maximum value Vmax. The system control unit 12 specifies that the metal M is placed when the average value is equal to or larger than the maximum value Vmax, and identifies that the device E is placed when the average value is equal to or smaller than the minimum value Vmin. To do. Further, the system control unit 12 specifies that the device E is not placed when the average value is between the maximum value Vmax and the minimum value Vmin.

  In other words, the output voltage Vs acquired immediately after the energization of the high-frequency current of the detection frequency fs is stopped is performed a plurality of times, and the average value of the plurality of output voltages Vs obtained by the plurality of times is used in the power supply area AR. It is specified whether or not E and metal M are placed. Therefore, the accuracy of specifying can be further improved by averaging.

  In this case, the output detection circuit 25 calculates the average value of the acquired plurality of output voltages Vs. The output detection circuit 25 outputs the acquired plurality of output voltages Vs to the system control unit 12. Then, the system control unit 12 may calculate the average value of the plurality of output voltages Vs and compare the average value with the minimum value Vmin and the maximum value Vmax.

In the above embodiment, only one output voltage Vs immediately after the energization of the high-frequency current having the detection frequency fs is stopped is acquired.
As shown in FIG. 11, this is the minimum value Vmin that specifies that the device E is placed when the device E is placed under the condition that the device E is not placed after the energization is stopped. Acquire multiple items in time series until the time that does not reach. In FIG. 11, three output voltages Vs are acquired at three points P1, P2, and P3 in the attenuation region Z3.

  Then, the output detection circuit 25 calculates an average value of the plurality of output voltages Vs acquired in time series and outputs the average value to the system control unit 12. The system control unit 12 may specify whether or not the device E is arranged in the primary coil L1 based on the average value. In this case, the specifying accuracy can be further improved without taking the time required for specifying.

  In this case, the output detection circuit 25 calculates the average value of the plurality of output voltages Vs acquired in time series. The output detection circuit 25 outputs a plurality of output voltages acquired in time series to the system control unit 12. Then, the system control unit 12 may determine the average value of the plurality of output voltages Vs acquired in time series and compare the average value with the minimum value Vmin and the maximum value Vmax.

  In the above embodiment, when device detection is performed, immediately after the energization is stopped, that is, the output voltage Vs in the attenuation region Z3 is acquired, the output voltage Vs in the saturation region Z2 and the output in the attenuation region Z3 The voltage Vs may be acquired and used in combination.

  More specifically, as shown in FIG. 12, in the output detection circuit 25, the primary coil L <b> 1 is energized and is determined by a resistance component such as an inductance component, a capacitance component, a wiring resistance, and an internal resistance on the power feeding device 1 side. A plurality of output voltages Vs in the saturation region Z2 saturated with transient characteristics are sampled in time series. In FIG. 12, six output voltages Vs are acquired at six points Pa to Pf in the saturation region Z2. The output detection circuit 25 obtains a deviation between the output voltages Vs obtained at that time, and obtains the magnitude of noise from the deviation.

  When the obtained noise level is smaller than a predetermined value, the output detection circuit 25 obtains an average value of a plurality of output voltages Vs sampled in time series, assuming that the influence of noise is small. Then, the system control unit 12 compares the obtained average value with the minimum value Vmin and the maximum value Vmax.

  On the other hand, if the obtained noise level is greater than a predetermined value, the output voltage Vs immediately after the energization is stopped is acquired assuming that the output voltage Vs in the saturation region Z2 cannot be used because the noise is large. Then, the system control unit 12 compares the acquired output voltage Vs with the minimum value Vmin and the maximum value Vmax.

  Therefore, when the noise is small, the average value of the plurality of output voltages Vs sampled in time series is compared with the minimum value Vmin and the maximum value Vmax, so that accurate detection can be performed. Further, when the noise is large, the output voltage Vs immediately after the energization is stopped is compared with the minimum value Vmin and the maximum value Vmax, so that accurate detection can be performed.

Moreover, since the output voltage Vs to be acquired is performed with the same waveform, optimal detection can be performed without increasing the acquisition time.
When the noise level is greater than a predetermined value, as shown in FIG. 10, the output detection circuit 25 acquires a plurality of output voltages Vs immediately after the energization is stopped every time the energization is stopped a plurality of times. The average value is obtained, and the average value is output to the system control unit 12. Then, the system control unit 12 may perform the average value to be compared with the minimum value Vmin and the maximum value Vmax.

  Of course, when the noise level is larger than a predetermined value, as shown in FIG. 11, the output detection circuit 25 has a plurality of time series in the attenuation region Z3 from the stop of energization of the high-frequency current of the detection frequency fs. Individual output voltage Vs is acquired. Then, the output detection circuit 25 calculates an average value of the plurality of output voltages Vs acquired in time series, and the system control unit 12 performs this average value with the minimum value Vmin and the maximum value Vmax. Also good.

  In addition, instead of the output detection circuit 25, the system control unit 12 determines the magnitude of noise from a plurality of output voltages Vs sampled in time series, and the plurality of sampled output voltages Vs when the noise is small. The average value may be calculated.

  In the above embodiment, the power feeding device 1 has the primary coils L1 arranged in parallel in the two-dimensional direction. This may be applied to a power feeding device in which a plurality of primary coils L1 are arranged in a one-dimensional direction. Of course, the primary coil L <b> 1 may be applied to one power supply device 1.

  In the above embodiment, the high-frequency current is generated by the half-bridge circuit 22, but may be implemented by other high-frequency oscillation circuits such as a full-bridge circuit.

  DESCRIPTION OF SYMBOLS 1 ... Non-contact electric power feeder (power feeder), 2 ... Housing, 3 ... Mounting surface, 5 ... Power receiving circuit, 6 ... Rectifier circuit, 7 ... Communication circuit, 10 ... Common unit part, 11 ... Power supply circuit, 12 ... System control unit (specifying unit), 13 ... memory, 20 ... basic unit unit, 21 ... basic power supply unit circuit, 22 ... half bridge circuit (high-frequency current generating unit), 23 ... drive circuit, 24 ... current detection circuit, 25 ... Output detection circuit (detection means, second detection means, identification means), 26 ... signal extraction circuit, E ... electric equipment (equipment), Z ... load, L1 ... primary coil, L2 ... secondary coil, C1, C2 ... Primary and secondary resonance circuits, Ca, Cb, first and second capacitors, Qa, Qb, first and second power transistors, ID, device authentication signal, RQ, power supply request signal, PSa, PSb, drive Signal, CT ... Control signal, S DESCRIPTION OF SYMBOLS 1 ... Current detection signal, SP ... Sampling signal, fr ... Resonance frequency, fp ... Power supply frequency, fs ... Detection frequency, Vmax ... Maximum value, Vmin ... Minimum value (reference voltage), Vdd ... DC voltage, Vs ... Output Voltage (detection voltage, second detection voltage), Z1... Unsaturated region, Z2... Saturation region, Z3... Attenuation region, P1 to P3, Pa to Pf.

Claims (7)

When an electrical device is disposed in a primary coil that generates an alternating magnetic field when a high-frequency current having a power feeding frequency is applied, the primary coil generates the alternating magnetic field and receives power provided to the electrical device by electromagnetic induction. An apparatus detection method for a non-contact power feeding device that generates secondary power in a secondary coil of the device,
Immediately after energizing the primary coil with a detection frequency high-frequency current and stopping the energization of the detection frequency high-frequency current to the primary coil, an inductance component, capacitance component, wiring resistance and internal A relative voltage relative to the primary current flowing through the primary coil that attenuates due to a transient characteristic determined by a resistance component such as a resistance is detected as a detection voltage, and the presence or absence of an electrical device is specified by the detection voltage. A device detection method for a non-contact power feeding device. In the apparatus detection method of the non-contact electric power feeder according to claim 1,
Immediately after the energization is stopped, when the electric device is arranged under the condition that the electric device is not arranged, from the energization stop of the high-frequency current of the detection frequency to the primary coil, A device detection method for a non-contact power feeding device, characterized in that it is a time before reaching a reference voltage that specifies that an electrical device is arranged. When an electrical device is disposed in a primary coil that generates an alternating magnetic field when a high-frequency current having a power feeding frequency is applied, the primary coil generates the alternating magnetic field and receives power provided to the electrical device by electromagnetic induction. A non-contact power feeding device configured to generate secondary power in a secondary coil of the device,
High-frequency current generating means for generating a high-frequency current having a detection frequency and energizing the primary coil;
Immediately after the energization of the high-frequency current having the detection frequency to the primary coil is stopped, the primary coil attenuates by a transient characteristic determined by a resistance component such as an inductance component, a capacitance component, a wiring resistance, or an internal resistance on the non-contact power feeding device side. Detection means for detecting a relative voltage relative to the primary current flowing in the coil as a detection voltage;
A non-contact power feeding apparatus comprising: a specifying unit that specifies whether or not the electric device is arranged in the primary coil based on a detection voltage detected by the detection unit. In the non-contact electric power feeder of Claim 3,
Immediately after the energization is stopped, when the electric device is arranged under the condition that the electric device is not arranged, from the energization stop of the high-frequency current of the detection frequency to the primary coil, A non-contact power feeding device, characterized in that it is a time before reaching a reference voltage that specifies that an electrical device is arranged. In the non-contact electric power feeder of Claim 3 or 4,
The high-frequency current generating means energizes the primary coil intermittently with a high-frequency current of the detection frequency a plurality of times,
The detection means detects the detection voltage immediately after the stop every time the energization is stopped,
The non-contact power feeding apparatus according to claim 1, wherein the specifying unit specifies whether the electric device is arranged in the primary coil based on an average value of the detected plurality of detection voltages. In the non-contact electric power feeder of Claim 3 or 4,
The detection means detects a plurality of detection voltages immediately after the energization stop in time series,
The non-contact power feeding apparatus according to claim 1, wherein the specifying unit specifies whether or not the electric device is arranged in the primary coil based on an average value of the plurality of detection voltages detected in time series. In the non-contact electric power feeder of any one of Claims 3-6,
The primary coil that is saturated by a transient characteristic determined by a resistance component such as an inductance component, a capacitance component, a wiring resistance, an internal resistance, or the like on the non-contact power feeding device side during energization of the high-frequency current having the detection frequency to the primary coil. A second detection means for detecting, as a second detection voltage, a relative voltage obtained by sampling a plurality of relative voltages relative to the primary current flowing in the time series;
The specifying means obtains a noise level based on the plurality of second detection voltages, and when the noise level is small, the primary coil is applied to the primary coil based on an average value of the plurality of second detection voltages. It is specified whether or not an electric device is arranged, and when the noise level is large, specifying whether or not the electric device is arranged in the primary coil based on a detected voltage immediately after the energization stop detected by the detecting means. A non-contact power feeding device.