JP2019009980A - Leakage detection device, wireless power transmission device, wireless power reception device, and wireless power transmission system - Google Patents

Abstract

An object of the present invention is to suppress erroneous detection due to noise and detect electric leakage with high accuracy. A leakage detection device (30) provided in a wireless power receiving device (20) including a rectification circuit (22) for converting an AC voltage into a DC voltage and a grounded metal member (MG), the output side (DC side) of the rectification circuit (22). ), and based on the average voltage A detected by the average voltage detection circuit 40 and the average voltage A detected by the average voltage detection circuit 40, and an earth leakage detection circuit 50 for detecting the presence or absence of an earth leakage. [Selection drawing] Fig. 1

Description

  The present invention relates to a leakage detection device, a wireless power transmission device, a wireless power reception device, and a wireless power transmission system.

  A wireless power transmission system that wirelessly transmits power from a power transmission coil to a power reception coil without using a power cable has attracted attention.

  The wireless power transmission system is configured to include a wireless power transmission device having a power transmission coil and a wireless power reception device having a power reception coil. In these devices, various components and internal devices are connected via cables. It is connected. If leakage occurs in this connection, it may lead to a secondary failure of the wireless power transmission system. Therefore, if a leakage occurs, it is necessary to quickly detect that fact.

  Patent Document 1 discloses a ground fault detection circuit that detects a leakage (ground fault) between a power line and a ground line used to supply a DC voltage from a rectifying and smoothing circuit in a power receiving adapter to a charging control device. Has been.

JP 2012-217246 A

  However, with the technique disclosed in Patent Document 1, there is a possibility that the leakage cannot be detected with high accuracy. That is, in general, a noise component is unavoidably superimposed on the voltage applied to the power line to be detected for leakage. The superposition of noise components means that the potential difference between the power line and the ground line changes, so it is not possible to accurately determine whether or not there is a leakage simply by monitoring this potential difference. .

  The present invention has been made in view of such a problem, and an object thereof is to provide a leakage detection device, a wireless power transmission device, a wireless power reception device, and a wireless power transmission system capable of detecting a leakage with high accuracy.

  The leakage detection device according to the present invention is a leakage detection device provided in a conversion circuit that converts one of a DC voltage and an AC voltage into the other, and a device including a grounded metal member, on the DC side of the conversion circuit. An average voltage detection circuit for detecting an average voltage corresponding to a potential difference between the high-voltage side terminal or the low-voltage side terminal and the metal member, and the presence or absence of leakage based on the average voltage detected by the average voltage detection circuit An earth leakage detection device comprising: an earth leakage detection circuit for detecting

  According to the present invention, since leakage is detected based on the average voltage, it is possible to suppress erroneous detection due to noise and detect leakage with high accuracy.

  In the leakage detection device, the average voltage detection circuit may be configured to detect an average voltage of a voltage corresponding to a potential difference between a low-voltage side terminal on a DC side of the conversion circuit and the metal member. Good. According to this, it becomes possible to detect a leakage more reliably.

  In each of the leakage detecting devices, the average voltage detection circuit includes a first resistance voltage dividing circuit that resistance-divides the potential difference, and a first average circuit that detects an average voltage of the output voltage of the first resistance voltage dividing circuit, It is good also as having. According to this, it is possible to detect a leakage in the DC line. In addition, if the DC line is connected to a configuration that serves as a power source, it is possible to detect a leakage even when power transmission is stopped.

  In each of the leakage detection devices, the average voltage detection circuit includes a capacitive voltage dividing circuit that capacitively divides the potential difference, a first rectifier circuit that rectifies an output of the capacitive voltage divider circuit, and an output voltage of the first rectifier circuit. It is good also as having having a 2nd average circuit which detects the average voltage of these. According to this, it is possible to detect leakage in the AC line during power transmission or weak excitation.

  In each of the leakage detection devices, the average voltage detection circuit includes a second resistance voltage dividing circuit that resistance-divides the potential difference, a differentiation circuit that differentiates an output of the second resistance voltage dividing circuit, and an output from the differentiation circuit. And a third average circuit that detects an average voltage of the output voltage of the second rectifier circuit. Also by this, it is possible to detect a leakage in the AC line during power transmission or weak excitation.

  In each of the leakage detection devices, the average voltage detection circuit includes a capacitive voltage dividing circuit that capacitively divides the potential difference, a first rectifier circuit that rectifies an output of the capacitive voltage divider circuit, and an output voltage of the first rectifier circuit. A second average circuit that detects an average voltage of the second average circuit, wherein the leakage detection circuit detects the presence or absence of a leakage based on the average voltage output from the first average circuit, and the second average circuit It is good also as including the 1st switching circuit which switches the operation | movement which detects the presence or absence of an electrical leakage based on the average voltage output from. According to this, since it is possible to detect the leakage in both the DC line and the AC line, it is possible to detect the leakage occurring in virtually every place.

  In each of the leakage detection devices, the average voltage detection circuit includes a second resistance voltage dividing circuit that resistance-divides the potential difference, a differentiation circuit that differentiates an output of the second resistance voltage dividing circuit, and an output from the differentiation circuit. And a third average circuit for detecting an average voltage of the output voltage of the second rectifier circuit, wherein the leakage detection circuit is an average voltage output from the first average circuit. And a second switching circuit that switches between an operation for detecting the presence / absence of electric leakage based on the above and an operation for detecting the presence / absence of electric leakage based on the average voltage output from the third average circuit. Also by this, it is possible to detect the leakage in both the direct current line and the alternating current line, so it is possible to detect the leakage occurring in virtually every place.

  Here, the first average circuit may be configured to detect an average voltage of the output voltage of the first resistance voltage dividing circuit using an averaging function of a low-pass filter, and the second average circuit may be An average voltage of the output voltage of the first rectifier circuit may be detected using an averaging function of a low-pass filter, and the third average circuit may be configured to detect the second voltage using an averaging function of the low-pass filter. It can be configured to detect an average voltage of the output voltage of the rectifier circuit.

  In each of the leakage detection devices, the leakage detection circuit includes a comparison circuit that compares the average voltage with a threshold value, and a detection circuit that detects the presence or absence of leakage based on a result of the comparison circuit. It is good also as including the some threshold value from which a voltage value differs. According to this, by comparing with a plurality of threshold values, it is possible to identify the location where the leakage has occurred.

  In each of the leakage detection devices, the leakage detection circuit includes a comparison circuit that compares the average voltage with a threshold value, and a detection circuit that detects the presence or absence of leakage based on a result of the comparison circuit. It may be configured to be changeable to an arbitrary value. According to this, by performing the comparison while changing the threshold value, it is possible to identify the location where the leakage has occurred.

  In each of the leakage detection devices, the leakage detection circuit includes an AD conversion circuit that converts the average voltage into a digital signal, and a detection circuit that detects the presence or absence of leakage based on the average voltage converted by the AD conversion circuit; It is good also as including. According to this, it becomes possible to detect the presence or absence of electric leakage based on the average voltage after conversion by the AD conversion circuit.

  A wireless power transmission device according to the present invention is based on any one of the above leakage detection devices, a drive circuit that is the conversion circuit that converts a DC voltage into an AC voltage, the metal member, and an AC voltage supplied from the drive circuit. And a control circuit that stops the operation of the drive circuit in response to detection of electric leakage by the electric leakage detection circuit. According to this, since a power transmission operation can be stopped when a leakage occurs, a secondary failure can be suppressed.

  A wireless power transmission device according to another aspect of the present invention is supplied from any one of the above leakage detection devices, a drive circuit that is the conversion circuit that converts a DC voltage into an AC voltage, the metal member, and the drive circuit. A wireless power transmission apparatus comprising: a power transmission coil that generates an alternating magnetic field based on an alternating voltage to be transmitted; and a notification device that performs notification to a user or an external device in response to the leakage detection detected by the leakage detection circuit. According to this, when electric leakage occurs, it is possible to prompt stoppage of power transmission and repair, and therefore secondary failures can be suppressed.

  A wireless power receiving device according to the present invention includes any one of the above leakage detection devices, a power receiving coil that generates an AC voltage by receiving an AC magnetic field, and the conversion circuit that converts the AC voltage generated by the power receiving coil into a DC voltage. A transmitter that transmits a stop signal that urges a wireless power transmission device that generates the AC magnetic field to stop power transmission operation in response to a leakage detected by the rectifier circuit, the metal member, and the leakage detection circuit; A wireless power receiving apparatus. According to this, since a power transmission operation can be stopped when a leakage occurs, a secondary failure can be suppressed.

  A wireless power receiving device according to another aspect of the present invention includes any one of the above leakage detection devices, a receiving coil that receives an AC magnetic field to generate an AC voltage, and converts the AC voltage generated by the receiving coil into a DC voltage. A wireless power receiving apparatus comprising: a rectifier circuit that is the conversion circuit; the metal member; and a notification device that performs notification to a user or an external device in response to detection of leakage by the leakage detection circuit. According to this, when electric leakage occurs, it is possible to prompt stoppage of power transmission and repair, and therefore secondary failures can be suppressed.

  In each wireless power transmission device or each wireless power reception device, the metal member may be a metal shield plate that is disposed in the vicinity of the power transmission coil and shields leakage magnetic flux.

  A wireless power transmission system according to the present invention includes a wireless power transmission device and a wireless power reception device, and the wireless power transmission device is one of the wireless power transmission devices described above.

  A wireless power transmission system according to another aspect of the present invention includes a wireless power transmission device and a wireless power reception device, and the wireless power transmission device is any one of the wireless power reception devices described above.

  According to still another aspect of the present invention, a wireless power transmission system includes a wireless power transmission device and a wireless power reception device, and the wireless power transmission device is any one of the wireless power transmission devices described above, A wireless power transmission system, which is one of wireless power receiving apparatuses.

  According to the present invention, since leakage is detected based on the average voltage, it is possible to suppress erroneous detection due to noise and detect leakage with high accuracy.

It is a figure which shows the structure of the wireless power transmission system 1 which concerns on the 1st Embodiment of this invention, and the load 2 connected to this wireless power transmission system 1. FIG. (A)-(e) is a figure which shows the example of the internal structure of the average voltage detection circuit 40 shown in FIG. 1, respectively. (A) is a figure which shows the example of an internal structure of the resistance voltage dividing circuits 41 and 46 shown in FIG. 2, (b) is an example of the internal structure of the average circuits 42, 45, and 49 shown in FIG. (C) is a figure which shows the example of an internal structure of the capacity | capacitance voltage dividing circuit 43 shown in FIG. 2, (d) and (e) are respectively the rectifier circuits 44 shown in FIG. 48 is a diagram illustrating an example of the internal configuration of the differential circuit 47, and FIG. 6F is a diagram illustrating an example of the internal configuration of the differentiation circuit 47 illustrated in FIG. (A) And (b) is a figure which shows the example of the internal structure of the leak detection circuit 50 shown in FIG. 1, respectively. FIG. 4 is a diagram showing another example of the internal configuration of the averaging circuits 42, 45, and 49 shown in FIG. It is a figure which shows the structure of the wireless power transmission system 1 which concerns on the 2nd Embodiment of this invention, and the load 2 connected to this wireless power transmission system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited by the contents described below. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the same reference numerals are used for the same elements or elements having the same function in the description, and a duplicate description is omitted.

  FIG. 1 is a diagram showing a configuration of a wireless power transmission system 1 according to a first embodiment of the present invention and a load 2 connected to the wireless power transmission system 1. As shown in the figure, the wireless power transmission system 1 includes a wireless power transmission device 10 and a wireless power reception device 20. The load 2 is connected to the wireless power receiving device 20.

  The wireless power transmission system 1 is a system used for power transmission to a moving body such as an electric vehicle (EV: Electric Vehicle) or a hybrid vehicle (HV: Hybrid Vehicle) that uses the power of a secondary battery. In this case, the wireless power transmission device 10 is mounted in a power transmission facility disposed on the ground, and the wireless power reception device 20 is mounted on a vehicle. Hereinafter, the description will be continued assuming that the wireless power transmission system 1 is for power transmission to an electric vehicle.

  As shown in FIG. 1, the wireless power transmission apparatus 10 includes a DC power source 11, a drive circuit 12, a control circuit 13, a receiver 14, a power transmission coil L1, and a power transmission side capacitor C1.

  The DC power supply 11 serves to supply DC power to the drive circuit 12. The specific type of the DC power supply 11 is not particularly limited as long as it can supply DC power. For example, a DC power source obtained by rectifying and smoothing a commercial AC power source, a secondary battery, a DC power source generated by solar power, or a switching power source such as a switching converter can be suitably used as the DC power source 11.

  The drive circuit 12 is a conversion circuit that converts a DC voltage supplied from the DC power supply 11 into an AC voltage. For example, the drive circuit 12 includes a switching circuit (a full bridge circuit, not shown) in which four switching elements are bridge-connected. Is done. The drive circuit 12 serves to supply an alternating current to the power transmission coil L1.

  The control circuit 13 is a circuit that controls the operation of the drive circuit 12 so that the frequency of the alternating current supplied to the power transmission coil L1 is equal to a predetermined power transmission frequency fp. For example, if the drive circuit 12 is the above-described full bridge circuit, the control circuit 13 configures the full bridge circuit so that the frequency of the alternating current supplied to the power transmission coil L1 is equal to the predetermined power transmission frequency fp. A control signal for each switching element is generated. A specific value of the power transmission frequency fp is set to, for example, 20 [kHz] to 200 [kHz].

  The receiver 14 is a communication device configured to be able to receive an arbitrary signal from a transmitter 70 provided in the wireless power receiving apparatus 20. Communication between the receiver 14 and the transmitter 70 may be realized by short-range wireless communication such as Bluetooth (registered trademark), or may be realized by a wireless LAN such as Wi-Fi (registered trademark). . The signal received by the receiver 14 from the transmitter 70 includes a result signal R indicating the detection result of the presence or absence of leakage by the leakage detection device 30 described later.

  When receiving the result signal R, the receiver 14 is configured to output the received result signal R to the control circuit 13. When the result signal R input from the receiver 14 indicates the detection of leakage by the leakage detection device 30, the control circuit 13 stops the operation of the drive circuit 12 accordingly. Specifically, for example, when the drive circuit 12 is the above-described full bridge circuit, all the switching elements constituting the full bridge circuit are turned off. Thereby, since power transmission operation is stopped, it becomes possible to suppress the secondary failure of the wireless power transmission system 1 due to electric leakage.

  The power transmission coil L1 and the power transmission side capacitor C1 are connected in series between one side terminal on the output side (AC side) and the other side terminal of the drive circuit 12 to constitute a resonance circuit. The resonance circuit has a resonance frequency that is the same as or close to the above-described power transmission frequency fp, and plays a role of generating an alternating magnetic field based on the alternating current supplied from the drive circuit 12. In addition, it is good also as connecting the power transmission side capacitor | condenser C1 and the power transmission coil L1 in parallel between the one side terminal of the output side of the drive circuit 12, and the other side terminal.

  The power transmission coil L1 has, for example, a spiral structure formed by winding a litz wire obtained by twisting about 2,000 insulated copper wires of φ0.1 (mm) into a flat shape from several turns to several tens of turns. For example, the coil is disposed in the ground or near the ground. When an alternating current is supplied from the drive circuit 12 to the power transmission coil L1, an alternating magnetic field is thereby generated. This alternating magnetic field generates an electromotive force in the power receiving coil L2 by a mutual inductance between the power transmitting coil L1 and a power receiving coil L2 described later, thereby realizing transmission of power.

  Next, as shown in FIG. 1, the wireless power receiving device 20 includes a power receiving coil L2, power receiving side capacitors C2 and C3, a rectifier circuit 22, bypass capacitors C4 to C6, a leakage detecting device 30, a notification device 60, and a transmitter 70. It is comprised.

  The power receiving coil L <b> 2 and the power receiving side capacitor C <b> 2 are connected in series between the one side terminal and the other side terminal on the input side (AC side) of the rectifier circuit 22. The power receiving side capacitor C3 is connected in parallel with the power receiving coil L2 and the power receiving side capacitor C2. With these connections, the power receiving coil L2 and the power receiving side capacitors C2 and C3 constitute a resonance circuit. The resonance frequency of this resonance circuit is also set to be the same as or close to the power transmission frequency fp described above. This resonance circuit serves as a power receiving unit that wirelessly receives AC power transmitted from the power transmission coil L1.

  Similarly to the power transmission coil L1, the power receiving coil L2 is formed by winding a litz wire obtained by twisting, for example, about 2,000 insulated copper wires having a diameter of 0.1 mm from several turns to several tens of turns in a planar shape. It is the coil of the spiral structure formed by. On the other hand, the installation position of the power receiving coil L2 is different from that of the power transmitting coil L1, and is, for example, the lower part of the electric vehicle. When the magnetic flux generated by the power transmission coil L1 is linked to the power reception coil L2, an alternating current flows through the power reception coil L2 due to electromagnetic induction. This alternating current is converted into a direct current by the rectifier circuit 22 and then supplied to the load 2. Thereby, supplying DC power to the load 2 is realized.

  The rectifier circuit 22 is a conversion circuit that converts the AC voltage supplied from the power receiving coil L2 into a DC voltage. Specifically, it has a function of converting an alternating current supplied from the power receiving coil L2 into a direct current and supplying it to the load 2. For example, a bridge circuit in which a plurality of diodes are bridge-connected ( (Not shown).

  The bypass capacitors C4 to C6 are capacitors installed for the purpose of suppressing fluctuations in the output voltage of the rectifier circuit 22 that is a DC voltage. The bypass capacitor C4 is connected between the high-voltage side terminal and the low-voltage side terminal on the output side (DC side) of the rectifier circuit 22, and the bypass capacitor C5 is connected between the high-voltage side terminal on the output side of the rectifier circuit 22 and the ground line. The bypass capacitor C6 is connected between the low-voltage side terminal on the output side of the rectifier circuit 22 and the ground line.

  Although not shown, the load 2 includes a charger and a battery. Among these, the charger is a circuit having a function of charging the battery based on the DC power output from the rectifier circuit 22. This charging is performed by constant voltage constant current charging (CVCC charging), for example. A specific type of battery is not particularly limited as long as it has a function of storing electric power. For example, a secondary battery (such as a lithium ion battery, a lithium polymer battery, or a nickel battery) or a capacitive element (such as an electric double layer capacitor) can be suitably used as the battery that constitutes the load 2.

The leakage detection device 30 is a device for detecting leakage of a power line in the wireless power reception device 20. Specifically, as shown in FIG. 1, a low-voltage side terminal (voltage V _L ) on the output side of the rectifier circuit 22 and a metal member MG (voltage V _G ) provided in the vicinity of the power receiving coil L2 for magnetic flux shielding. an average voltage detecting circuit 40 for detecting an average voltage a of the voltage corresponding to the potential difference V _L -V _G, based on the average voltage a detected by the average voltage detector circuit 40 detects the presence or absence of leakage between, And a leakage detection circuit 50 that outputs a result signal R indicating the result. The metal member MG is a metal shield plate, for example, and is grounded as shown in FIG. In FIG. 1, the output-side low-voltage side terminal of the rectifier circuit 22 is connected to the average voltage detection circuit 40, but the output-side high-voltage side terminal of the rectifier circuit 22 is connected to the average voltage detection circuit 40. Also good. The average voltage detection circuit 40 in this case is a circuit that detects an average voltage of a voltage corresponding to a potential difference between the high-voltage side terminal on the output side of the rectifier circuit 22 and the metal member MG. Details of the leakage detection device 30 will be separately described later.

  The notification device 60 notifies the user or an external device in response to the leakage detection device 30 detecting a leakage (that is, the result signal R indicating that the leakage has been detected is supplied from the leakage detection device 30). The device to be executed. Specific devices for executing the notification to the user include, for example, a bell that notifies the user of detection of electric leakage with an alarm sound, a lamp that notifies the user of detection of electric leakage with light, and the like. Moreover, as an external apparatus used as the object of notification by the alerting | reporting device 60, the various systems in a vehicle (including the charger of the load 2 mentioned above) etc. are mentioned, for example.

  The transmitter 70 is a circuit that transfers the result signal R supplied from the leakage detection device 30 to the receiver 14. As described above, the receiver 14 is configured to output the result signal R received from the transmitter 70 to the control circuit 13, and the control circuit 13 uses the result signal R input from the receiver 14 as the leakage detection device 30. In the case where it indicates the detection of the electric leakage due to, the operation of the drive circuit 12 is stopped accordingly. Therefore, it can be said that the result signal R indicating the detection of leakage by the leakage detection device 30 is a stop signal that prompts the wireless power transmission device 10 to stop the power transmission operation.

  Hereinafter, a specific configuration of the leakage detection device 30 will be described in detail with reference to FIGS.

  2A to 2E are diagrams showing examples of the internal configuration of the average voltage detection circuit 40 shown in FIG. 3A is a diagram showing an example of the internal configuration of the resistance voltage dividing circuits 41 and 46 shown in FIG. 2, and FIG. 3B is a diagram showing the average circuits 42, 45, and 4 shown in FIG. 49 is a diagram showing an example of the internal configuration of 49, FIG. 3C is a diagram showing an example of the internal configuration of the capacitive voltage dividing circuit 43 shown in FIG. 2, and FIGS. 3D and 3E are diagrams. FIG. 3 is a diagram showing an example of the internal configuration of each of the rectifier circuits 44 and 48 shown in FIG. 2, and FIG. 3F is a diagram showing an example of the internal configuration of the differentiating circuit 47 shown in FIG.

  The average voltage detection circuit 40 according to the first example shown in FIG. 2A includes a resistance voltage dividing circuit 41 (first resistance voltage dividing circuit) and an average circuit 42 (first average circuit).

The resistor divider 41 is a circuit for generating a voltage V1 by pressure resistance of the potential difference V _L -V _G described above, as shown in FIG. 3 (a), the input terminal and the voltage V _G of the voltage V _L And two resistance elements connected in series with each other. Voltage V1 is a voltage across the closer to the input terminal of the voltage V _G of the two resistance elements. When the resistance values of the two resistance elements are equal, V1 = (V _G −V _L ) / 2.

  The average circuit 42 is a circuit that detects an average voltage A of the output voltage V1 of the resistance voltage dividing circuit 41, and is configured by a low-pass filter including a capacitor and a resistance element, as shown in FIG. The averaging circuit 42 according to the present embodiment is configured to detect the average voltage A using the averaging action of this low-pass filter.

  According to the average voltage detection circuit 40 according to the first example, it is possible to detect a leakage in the DC line of the wireless power receiving apparatus 20 (specifically, the wiring connected to the output terminal of the rectifier circuit 22). Further, since the DC line is connected to the load 2, the average voltage detection circuit 40 according to the first example can detect a leakage even when power transmission is stopped.

  The average voltage detection circuit 40 according to the second example shown in FIG. 2B includes a capacitance voltage dividing circuit 43, a rectifier circuit 44 (first rectifier circuit), and an average circuit 45 (second average circuit). The

Capacity divider circuit 43 is a circuit for generating a voltage V2 by capacitive division potential difference V _L -V _G described above, as shown in FIG. 3 (c), the input terminal and the voltage V _G of the voltage V _L And two capacitance elements connected in series with each other. Voltage V2 is a voltage across the closer to the input terminal of the voltage V _G of the two capacitance elements.

  The rectifier circuit 44 is a circuit that generates the voltage V3 by rectifying the output voltage V2 of the capacitance voltage divider circuit 43, and includes one or more diodes as shown in FIG. 3 (d) or FIG. 3 (e). Consists of. More specifically, the rectifier circuit 44 according to the example of FIG. 3D has a single diode having an anode connected to the high-voltage side input terminal and a cathode connected to the high-voltage side output terminal. On the other hand, the rectifier circuit 44 according to the example of FIG. 3 (e) includes a diode having an anode connected to the high-voltage side input terminal and a cathode connected to the high-voltage side output terminal, an anode connected to the low-voltage side input terminal, and a cathode connected to the high-voltage side output terminal. Each of the diodes connected has a diode whose anode is connected to the low-voltage side output terminal and a cathode is connected to the high-voltage side input terminal, and a diode whose anode is connected to the low-voltage side output terminal and the cathode is connected to the low-voltage side input terminal. Configured.

  The average circuit 45 is a circuit that detects the average voltage A of the output voltage V3 of the rectifier circuit 44, and is configured by a low-pass filter similar to the average circuit 42 as shown in FIG. The averaging circuit 45 according to the present embodiment is configured to detect the average voltage A using the averaging action of this low-pass filter.

  According to the average voltage detection circuit 40 according to the second example, it is possible to detect a leakage in the AC line of the wireless power receiving apparatus 20 (specifically, a wiring connected to the input terminal of the rectifier circuit 22). This utilizes the fact that the potential of the metal member MG fluctuates when the AC current flowing through the AC line leaks to the metal member MG. Since the AC current flows through the AC line only when the wireless power transmission system 1 is transmitting power or weakly excited, leakage in the AC line can be detected by the average voltage detection circuit 40 according to the second example. Is only during power transmission or weak excitation.

  An average voltage detection circuit 40 according to the third example shown in FIG. 2C includes a resistance voltage dividing circuit 46 (second resistance voltage dividing circuit), a differentiating circuit 47, a rectifying circuit 48 (second rectifying circuit), And an average circuit 49 (third average circuit).

Resistor divider 46 is a circuit for generating a voltage V1 by pressure resistance of the potential difference V _L -V _G described above, as shown in FIG. 3 (a), by the same circuit as the resistor divider 41 Composed. Specifically, is configured to include two resistors connected in series between the input terminal of the input terminal and the voltage V _G of the voltage V _L, the input terminal of the voltage V _G of the two resistance elements The voltage at both ends becomes the voltage V1.

  The differentiating circuit 47 is a circuit that generates the voltage V4 by differentiating the output voltage V1 of the resistance voltage dividing circuit 46, and is constituted by a high-pass filter composed of a capacitor and a resistance element, as shown in FIG. .

  The rectifier circuit 48 is a circuit that generates the voltage V3 by rectifying the output voltage V4 of the differentiating circuit 47. As shown in FIG. 3D or 3D, the rectifier circuit 48 is a circuit similar to the rectifier circuit 44. Composed.

  The average circuit 49 is a circuit that detects the average voltage A of the output voltage V3 of the rectifier circuit 48, and is configured by a low-pass filter similar to the average circuits 42 and 45, as shown in FIG. The averaging circuit 49 according to the present embodiment is configured to detect the average voltage A using the averaging action of this low-pass filter.

  The average voltage detection circuit 40 according to the third example can also detect a leakage in the AC line of the wireless power receiving apparatus 20 (specifically, the wiring connected to the input terminal of the rectifier circuit 22). This also utilizes the fact that the potential of the metal member MG fluctuates when the AC current flowing through the AC line leaks to the metal member MG. Also in the third example, the leakage in the AC line can be detected only during power transmission or weak excitation.

  The average voltage detection circuit 40 according to the fourth example shown in FIG. 2D includes a circuit according to the first example shown in FIG. 2A and a circuit according to the second example shown in FIG. Are connected in parallel, thereby outputting two types of average voltages A1, A2. As described above, according to the circuit according to the first example, the leakage in the DC line of the wireless power receiving device 20 can be detected, and according to the circuit according to the second example, the leakage in the AC line of the wireless power receiving device 20 can be detected. Therefore, according to the average voltage detection circuit 40 according to the fourth example, it is possible to detect leakage in both the DC line and the AC line. Therefore, it is possible to detect leakage occurring in virtually every place in the wireless power receiving apparatus 20.

  The average voltage detection circuit 40 according to the fifth example shown in FIG. 2E includes a circuit according to the first example shown in FIG. 2A and a circuit according to the third example shown in FIG. Are connected in parallel, thereby outputting two types of average voltages A1, A2. As described above, according to the circuit according to the first example, the leakage in the DC line of the wireless power receiving device 20 can be detected. According to the circuit according to the third example, the leakage in the AC line of the wireless power receiving device 20 can be detected. Therefore, the average voltage detection circuit 40 according to the fifth example can also detect the leakage in both the DC line and the AC line. Therefore, it is possible to detect leakage occurring in virtually every place in the wireless power receiving apparatus 20.

  Next, FIG. 4A and FIG. 4B are diagrams showing examples of the internal configuration of the leakage detecting circuit 50 shown in FIG.

  The leakage detection circuit 50 according to the example shown in FIG. 4A is used with the average voltage detection circuit 40 shown in FIGS. 2A to 2C, and includes an AD conversion circuit 52, a comparison circuit 53, and the like. And a detection circuit 54.

  The AD conversion circuit 52 is a circuit that converts the average voltage A input from the average voltage detection circuit 40 into a digital signal. Specifically, the digital signal is generated by sampling the average voltage A at a predetermined sampling frequency and quantizing the result. The comparison circuit 53 is a circuit that compares the average voltage A converted by the AD conversion circuit 52 with a threshold value. The threshold value is stored in advance in the comparison circuit 53, for example. The detection circuit 54 is a circuit that detects the presence or absence of leakage based on the result of the comparison circuit 53. The output of the detection circuit 54 is supplied as a result signal R to the alarm device 60 and the transmitter 70 shown in FIG.

  Here, the threshold value to be compared by the comparison circuit 53 may include a plurality of threshold values having different voltage values. In this case, the comparison circuit 53 outputs a plurality of comparison results corresponding to each of the plurality of threshold values. In general, the specific value of the average voltage A varies depending on the location where the leakage occurs. Therefore, by preparing a plurality of threshold values in this way, it is possible to identify a location where a leakage has occurred from a plurality of comparison results output from the comparison circuit 53.

  The threshold stored in the comparison circuit 53 may be configured to be changeable to an arbitrary value. Then, the comparison circuit 53 may perform comparison for each threshold while changing the threshold. This also makes it possible to identify the location where the leakage has occurred from the plurality of comparison results output from the comparison circuit 53 as described above.

  Further, the AD conversion circuit 52 may not be provided in the leakage detection circuit 50, and the average voltage A input from the average voltage detection circuit 40 may be directly supplied to the comparison circuit 53. In this case, the comparison circuit 53 needs to be configured by a circuit that compares the average voltage A, which is an analog signal, with a threshold value.

  Further, instead of the processing by the comparison circuit 53 and the detection circuit 54, the presence or absence of electric leakage may be detected by another method. For example, a lookup table is prepared for associating the value of the average voltage A with the presence / absence of leakage, and when the average voltage A is output from the AD conversion circuit 52, the presence / absence of leakage corresponding to the average voltage A is read. It is good also as detecting the presence or absence of.

  The leakage detection circuit 50 according to the example shown in FIG. 4B is used together with the average voltage detection circuit 40 shown in FIG. 2D or FIG. This is different from the leakage detection circuit 50 according to the example shown in FIG. Since the other points are the same as the leakage detection circuit 50 according to the example shown in FIG. 4A, only the switching circuit 51 will be described below.

  When the switching circuit 51 is used together with the average voltage detection circuit 40 shown in FIG. 2D, the switching circuit 51 detects the presence or absence of leakage based on the average voltage A1 output from the average circuit 42, and the average circuit 45. This is a circuit (first switching circuit) that switches between the operation of detecting the presence or absence of leakage based on the average voltage A2 output from. When the switching circuit 51 is used together with the average voltage detection circuit 40 shown in FIG. 2E, the switching circuit 51 detects the presence or absence of leakage based on the average voltage A1 output from the average circuit 42, the average It is a circuit (second switching circuit) for switching between the operation of detecting the presence or absence of leakage based on the average voltage A2 output from the circuit 49. In any case, the leakage detection circuit 50 can detect the leakage in the DC line of the wireless power receiving apparatus 20 by detecting the presence or absence of leakage based on the average voltage A1, and based on the average voltage A2. By performing the operation of detecting the presence or absence of leakage, leakage in the AC line of the wireless power receiving apparatus 20 can be detected. Therefore, it is possible to detect leakage occurring in virtually every place in the wireless power receiving apparatus 20.

As described above, according to this embodiment, since based on the average voltage A of the voltage V1 corresponding to the potential difference V _L -V _G detects the leakage, to suppress erroneous detection due to noise, high-precision It becomes possible to detect electric leakage. In addition, depending on the specific circuit configuration in the leakage detection circuit 50, it is possible to detect leakage that has occurred in almost every place in the wireless power receiving apparatus 20. Furthermore, by using a plurality of threshold values, it is possible to specify the location where the leakage has occurred.

  In the above embodiment, the leakage detection circuit 50 according to the example shown in FIG. 4A has been described as being used together with the average voltage detection circuit 40 shown in FIGS. 2A to 2C. It is also possible to use the leakage detection circuit 50 according to the example shown in FIG. 4 (a) together with the average voltage detection circuit 40 shown in FIG. 2 (d) or FIG. 2 (e). The leakage detection device 30 in this case is provided with a leakage detection circuit 50 according to the example shown in FIG. 4A for each of the two types of average voltages A1 and A2 output from the average voltage detection circuit 40.

  In the above-described embodiment, an example in which the averaging circuits 42, 45, and 49 are configured by low-pass filters has been described. However, the averaging circuits 42, 45, and 49 may be circuits that can detect the average voltage of each input voltage. The averaging circuits 42, 45, and 49 can be configured by other types of circuits. Examples of such a circuit include, for example, an FIR (Finite Impulse Response) type digital filter and a circuit (integration circuit) using an operational amplifier as shown in FIG. Note that when an FIR type digital filter is used as the averaging circuits 42, 45, and 49, the AD conversion circuit 52 that constitutes the leakage detection circuit 50 is omitted.

  FIG. 6 is a diagram showing a configuration of the wireless power transmission system 1 according to the second embodiment of the present invention and a load 2 connected to the wireless power transmission system 1. The wireless power transmission system 1 according to the present embodiment is different from the wireless power transmission system 1 according to the first embodiment in that the leakage detection device 30 and the alarm 60 are provided in the wireless power transmission device 10. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals, and description will be made by paying attention to differences from the first embodiment.

The average voltage detection circuit 40 according to the present embodiment has a potential difference V _L −V between the input side (DC side) low voltage side terminal (voltage V _L ) of the drive circuit 12 and the metal member MG (voltage V _G ). An average voltage A of the voltage corresponding to _G is detected. However, the metal member MG according to the present embodiment is provided in the vicinity of the power transmission coil L1 for magnetic flux shielding. The other points are the same as the average voltage detection circuit 40 according to the first embodiment. As in the first embodiment, the average voltage detection circuit 40 is configured to detect the average voltage A of the voltage corresponding to the potential difference between the high-voltage side terminal on the input side of the drive circuit 12 and the metal member MG. May be.

  The leakage detection circuit 50 and the notification device 60 have the same configuration and function as the leakage detection circuit 50 and the notification device 60 according to the first embodiment, respectively. That is, the leakage detection circuit 50 detects the presence or absence of leakage based on the average voltage A detected by the average voltage detection circuit 40, and outputs a result signal R indicating the result. Moreover, the alerting device 60 performs notification with respect to a user or an external apparatus according to the leak detection apparatus 30 detecting a leak.

  Here, in the present embodiment, since the control circuit 13 and the leakage detection device 30 are located in the same device, the result signal R passes through the transmitter 70 and the receiver 14 shown in FIG. Instead, it is supplied directly from the leakage detection device 30 to the control circuit 13. The operation of the control circuit 13 that has received the result signal R is the same as that in the first embodiment.

As described above, also in this embodiment, since it based on the average voltage A of the voltage V1 corresponding to the potential difference V _L -V _G detects the leakage, to suppress erroneous detection due to noise, with high accuracy It becomes possible to detect electric leakage. In addition, depending on the specific circuit configuration in the leakage detection circuit 50, it is possible to detect leakage that has occurred at any location in the wireless power receiving device 20, and by using a plurality of thresholds, The point where it is also possible to specify the location where the electric leakage has occurred is the same as in the first embodiment.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to such embodiment at all, and this invention can be implemented in various aspects in the range which does not deviate from the summary. Of course.

  For example, in the above-described embodiment, the configuration in which the leakage detection device 30 is provided in the wireless power reception device 20 and the configuration in which the leakage detection device 30 is provided in the wireless power transmission device 10 have been described. However, the wireless power reception device 20 and the wireless power transmission device are described. It is good also as providing the earth-leakage detection apparatus 30 in both. In this case, it is preferable to configure the wireless power transmission system 1 so that the operation of the drive circuit 12 is stopped regardless of which leakage detection device 30 detects the leakage.

DESCRIPTION OF SYMBOLS 1 Wireless power transmission system 2 Load 10 Wireless power transmission device 11 DC power supply 12 Drive circuit 13 Control circuit 14 Receiver 20 Wireless power receiving device 22 Rectifier circuit 30 Leakage detection device 40 Average voltage detection circuit 41, 46 Resistance voltage dividing circuit 42, 45, 49 Averaging circuit 43 Capacitance voltage dividing circuit 44, 48 Rectifier circuit 47 Differentiating circuit 50 Leakage detection circuit 51 Switching circuit 52 AD conversion circuit 53 Comparison circuit 54 Detection circuit 60 Alarm 70 Transmitter A, A1, A2 Average voltage C1 Power transmission side capacitor C2, C3 Power reception side capacitors C4 to C6 Bypass capacitor L1 Power transmission coil L2 Power reception coil MG Metal member R Result signal

Claims (22)

A conversion circuit for converting one of a DC voltage and an AC voltage into the other, and a leakage detection device provided in a device including a grounded metal member,
An average voltage detection circuit for detecting an average voltage of a voltage corresponding to a potential difference between a high-voltage side terminal or a low-voltage side terminal on the DC side of the conversion circuit and the metal member;
A leakage detection circuit for detecting the presence or absence of leakage based on the average voltage detected by the average voltage detection circuit;
A leakage detection device comprising: The average voltage detection circuit is configured to detect an average voltage of a voltage corresponding to a potential difference between a low-voltage side terminal on a DC side of the conversion circuit and the metal member.
The leakage detection device according to claim 1. The average voltage detection circuit includes:
A first resistance voltage dividing circuit for resistance-dividing the potential difference;
A first average circuit for detecting an average voltage of the output voltage of the first resistance voltage dividing circuit;
Having
The leakage detecting device according to claim 1 or 2. The average voltage detection circuit includes:
A capacitive voltage dividing circuit for capacitively dividing the potential difference;
A first rectifier circuit for rectifying the output of the capacitive voltage divider circuit;
A second average circuit for detecting an average voltage of the output voltage of the first rectifier circuit;
Having
The leakage detection device according to any one of claims 1 to 3. The average voltage detection circuit includes:
A second resistance voltage dividing circuit for resistance-dividing the potential difference;
A differentiating circuit for differentiating the output of the second resistance voltage dividing circuit;
A second rectifier circuit for rectifying the output from the differentiating circuit;
A third average circuit for detecting an average voltage of the output voltage of the second rectifier circuit;
Having
The leakage detection device according to any one of claims 1 to 3. The average voltage detection circuit includes:
A capacitive voltage dividing circuit for capacitively dividing the potential difference;
A first rectifier circuit for rectifying the output of the capacitive voltage divider circuit;
A second average circuit for detecting an average voltage of the output voltage of the first rectifier circuit;
Have
The leakage detection circuit detects the presence / absence of leakage based on the average voltage output from the first average circuit, and detects the presence / absence of leakage based on the average voltage output from the second average circuit. A first switching circuit that switches between,
The electric leakage detection apparatus according to claim 3. The average voltage detection circuit includes:
A second resistance voltage dividing circuit for resistance-dividing the potential difference;
A differentiating circuit for differentiating the output of the second resistance voltage dividing circuit;
A second rectifier circuit for rectifying the output from the differentiating circuit;
A third average circuit for detecting an average voltage of the output voltage of the second rectifier circuit;
Have
The leakage detection circuit detects the presence or absence of leakage based on the average voltage output from the first average circuit, and detects the presence or absence of leakage based on the average voltage output from the third average circuit. A second switching circuit for switching between,
The electric leakage detection apparatus according to claim 3. The first averaging circuit is configured to detect an average voltage of an output voltage of the first resistance voltage dividing circuit using an averaging function of a low-pass filter;
The leakage detection device according to any one of claims 3 to 7. The second average circuit is configured to detect an average voltage of the output voltage of the first rectifier circuit using an averaging action of a low-pass filter;
The leakage detecting device according to claim 4 or 6. The third average circuit is configured to detect an average voltage of the output voltage of the second rectifier circuit using an averaging function of a low-pass filter;
The leakage detection device according to claim 5 or 7. The leakage detection circuit is
A comparison circuit for comparing the average voltage with a threshold;
A detection circuit that detects the presence or absence of leakage based on the result of the comparison circuit,
The threshold includes a plurality of thresholds having different voltage values.
The leakage detection device according to any one of claims 1 to 10. The leakage detection circuit is
A comparison circuit for comparing the average voltage with a threshold;
A detection circuit that detects the presence or absence of leakage based on the result of the comparison circuit,
The threshold is configured to be changeable to an arbitrary value.
The leakage detection device according to any one of claims 1 to 10. The leakage detection circuit is
An AD conversion circuit for converting the average voltage into a digital signal;
A detection circuit that detects the presence or absence of electric leakage based on the average voltage converted by the AD conversion circuit,
The leakage detection device according to any one of claims 1 to 10. The leakage detecting device according to any one of claims 1 to 13,
A drive circuit which is the conversion circuit for converting a DC voltage into an AC voltage;
The metal member;
A power transmission coil that generates an AC magnetic field based on an AC voltage supplied from the drive circuit;
A control circuit for stopping the operation of the drive circuit in response to detection of a leakage by the leakage detection circuit;
A wireless power transmission device comprising: The leakage detecting device according to any one of claims 1 to 13,
A drive circuit which is the conversion circuit for converting a DC voltage into an AC voltage;
The metal member;
A power transmission coil that generates an AC magnetic field based on an AC voltage supplied from the drive circuit;
In response to the detection of leakage by the leakage detection circuit, a notification device that performs notification to a user or an external device;
A wireless power transmission device comprising: The metal member is a metal shield plate that is disposed in the vicinity of the power transmission coil and shields leakage magnetic flux,
The wireless power transmission apparatus according to claim 14 or 15. The leakage detecting device according to any one of claims 1 to 13,
A receiving coil that generates an AC voltage in response to an AC magnetic field;
A rectifier circuit that is the conversion circuit that converts the AC voltage generated by the power receiving coil into a DC voltage;
The metal member;
A transmitter that transmits a stop signal that prompts the wireless power transmission device that generates the AC magnetic field to stop power transmission operation in response to the detection of the current leakage by the leakage detection circuit;
A wireless power receiving apparatus comprising: The leakage detecting device according to any one of claims 1 to 13,
A receiving coil that generates an AC voltage in response to an AC magnetic field;
A rectifier circuit that is the conversion circuit that converts the AC voltage generated by the power receiving coil into a DC voltage;
The metal member;
In response to the detection of leakage by the leakage detection circuit, a notification device that performs notification to a user or an external device;
A wireless power receiving apparatus comprising: The metal member is a metal shield plate that is disposed in the vicinity of the power receiving coil and shields leakage magnetic flux,
The wireless power receiving device according to claim 17 or 18. A wireless power transmitting device and a wireless power receiving device;
The wireless power transmission device is the wireless power transmission device according to any one of claims 14 to 16.
Wireless power transmission system. A wireless power transmitting device and a wireless power receiving device;
The wireless power receiving device is the wireless power receiving device according to any one of claims 17 to 19.
Wireless power transmission system. A wireless power transmitting device and a wireless power receiving device;
The wireless power transmission device is the wireless power transmission device according to any one of claims 14 to 16,
The wireless power receiving device is the wireless power receiving device according to any one of claims 17 to 19.
Wireless power transmission system.

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