Power transmission device, wireless power transmission system and processing method of power transmission device

Abstract

To determine whether or not power transmission circuits are abnormal by a simple configuration.SOLUTION: A power transmission device comprises: a power transmission antenna; a plurality of power transmission circuits each of which comprises a switching element, coverts DC power into AC power, and supplies the AC power to the power transmission antenna; a plurality of current detection units which outputs signals based on values of current flowing between the plurality of power transmission circuits and the power transmission antenna; and an abnormality determination unit which determines whether or not the power transmission circuits are abnormal on the basis of the signals.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a power transmitting device, a wireless power transmission system, and a processing method for a power transmitting device. [Background technology]

[0002] In recent years, wireless power transfer systems that wirelessly supply power of several kW or more to large electrically powered devices such as electric vehicles (EVs) have been researched and developed. As a result, the current and voltage flowing through the switching elements of wireless power transfer systems have become larger.

[0003] In order to avoid heat generation in elements due to current and to increase flexibility in element selection, Patent Document 1 describes a system in which multiple power transmission circuits are connected in parallel to distribute the current flowing through switching elements.

[0004] Furthermore, because wireless power transmission systems handle large amounts of power, if an abnormality occurs, it is necessary to quickly detect it and transition to safe operation or shut down the system. For example, Patent Document 2 describes a power transmission device that detects the current value of the input power supply and reduces or stops the current supplied to the power transmission coil depending on the change in the current value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5832702 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-220532 Summary of the Invention [Problem to be solved by the invention]

[0006] This paper describes a wireless power transmission system described in Patent Document 1, which connects multiple power transmission circuits in parallel and combines their outputs. If, while the system is operating, a switching element in one of the power transmission circuits experiences an abnormal state, such as an increase in on-resistance or an open state, this cannot be detected by the method described in Patent Document 2, which monitors the current value of the input power supply to the power transmission circuit. This is because power can be transmitted via another normal switching element connected in parallel.

[0007] An object of the present disclosure is to make it possible to determine whether or not a power transmission circuit is abnormal with a simple configuration. [Means for solving the problem]

[0008] The power transmission device includes a power transmission antenna, a plurality of power transmission circuits each including a switching element, converting DC power into AC power and supplying the AC power to the power transmission antenna, a plurality of current detection units each outputting a signal based on the value of a current flowing between the plurality of power transmission circuits and the power transmission antenna, and an abnormality determination unit that determines whether or not the plurality of power transmission circuits are abnormal based on the signal. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to determine whether or not a power transmission circuit is abnormal with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. [Figure 2] FIG. 2 is a diagram illustrating a configuration example of a power transmission circuit. [Figure 3] FIG. 1 illustrates an example of the configuration of an MCU. [Figure 4] FIG. [Figure 5] 10 is a flowchart of an abnormality detection. [Figure 6] FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. [Figure 10] FIG. 1 illustrates an example of the configuration of an MCU. [Figure 11] FIG. 10 is a diagram illustrating a simulation result. [Figure 12] 10 is a flowchart of an abnormality detection. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the embodiments will be described with reference to the drawings. Note that the wireless power transmission system in the present embodiment will be described as an example of a method called electromagnetic induction / magnetic resonance, which transmits power using a magnetic field or both an electric field and a magnetic field, but it can also be applied to an electric field coupling method, which transmits power mainly using an electric field.

[0012] (First embodiment) 1 is a diagram showing an example of the configuration of a wireless power transmission system 100 according to the first embodiment. The wireless power transmission system 100 includes a power transmitting device 101, a power receiving device 102, and a load 103, and transmits power wirelessly.

[0013] The power transmitting device 101 includes a power transmitting antenna 110, power transmitting circuits 111 and 112, a DC power supply 113, and a microcontroller (hereinafter referred to as MCU) 114. The power receiving device 102 includes a power receiving antenna 120 and a power receiving circuit 121.

[0014] The power transmitting circuits 111 and 112 are configured with known switching circuits used when employing an electromagnetic induction or magnetic field resonance method. The power transmitting circuits 111 and 112 each convert DC power supplied from a DC power supply 113 into AC power at the frequency of a clock signal CLK generated by an MCU 114, and supply the AC power to the power transmitting antenna 110. Thus, the power transmitting device 101 converts DC to AC in the power transmitting circuits 111 and 112, and generates an AC magnetic field in the power transmitting antenna 110.

[0015] The power transmitting circuits 111 and 112 receive a clock signal CLK having the same frequency and phase.

[0016] The power receiving antenna 120 is arranged to be coupled to the power transmitting antenna 110. The AC magnetic field generated by the power transmitting antenna 110 interlinks with the power receiving antenna 120. The power receiving circuit 121 is also configured with a known rectifier circuit used when employing an electromagnetic induction or magnetic resonance method.

[0017] Specifically, the power receiving circuit 121 converts AC power received by the power receiving antenna 120 into DC power and supplies the DC power to the load 103 .

[0018] In the case of the full-bridge circuit shown in FIG. 2, four current sensors 205-208 are implemented in the power transmitting circuits 111 and 112. The current sensors 205-208 output, for example, voltage signals Sense_out1-8 proportional to the value of the flowing current. The current sensors 205-208 of the power transmitting circuit 111 output voltage signals Sense_out1-4. The current sensors 205-208 of the power transmitting circuit 112 output voltage signals Sense_out5-8. The voltage signals Sense_out1-8 are input to the MCU 114, and are processed as data within the MCU 114. Next, the configuration of the power transmitting circuits 111 and 112 will be described using a full-bridge circuit as an example.

[0019] 2 is a diagram illustrating an example of the configuration of each of the power transmitting circuits 111 and 112 according to the first embodiment. Each of the power transmitting circuits 111 and 112 includes switching elements 201, 202, 203, and 204, current sensors 205, 206, 207, and 208, a gate drive circuit 209, and capacitors 210, 211, 212, and 213.

[0020] The switching elements 201, 202, 203 and 204 form a full bridge circuit.

[0021] The gate drive circuit 209 outputs signals PWM_P and PWM_N with a frequency and duty ratio synchronized with the clock signal CLK to drive the switching elements 201 to 204. The signals PWM_P and PWM_N are square wave signals whose phases are inverted by 180 degrees from each other.

[0022] A signal PWM_P is input to the switching elements 201 and 204. A signal PWM_N is input to the switching elements 202 and 203.

[0023] The current sensors 205 to 208 are connected in series to the switching elements 201 to 204, respectively. The current sensors 205 to 208 are current detection units that detect the values ​​of currents flowing through the switching elements 201 to 204 and output voltage signals Sense_out1 to Sense_out8 that are proportional to the current values. Here, the values ​​of the currents flowing through the switching elements 201 to 204 are also the currents that flow between the power transmitting circuits 111 and 112 and the power transmitting antenna 110, respectively.

[0024] Specifically, current sensor 205 in power transmitting circuit 111 outputs a voltage signal Sense_out1 proportional to the value of current flowing through switching element 201. Current sensor 206 in power transmitting circuit 111 outputs a voltage signal Sense_out2 proportional to the value of current flowing through switching element 202. Current sensor 207 in power transmitting circuit 111 outputs a voltage signal Sense_out3 proportional to the value of current flowing through switching element 203. Current sensor 208 in power transmitting circuit 111 outputs a voltage signal Sense_out4 proportional to the value of current flowing through switching element 204.

[0025] A current sensor 205 in the power transmitting circuit 112 outputs a voltage signal Sense_out5 proportional to the value of a current flowing through the switching element 201. A current sensor 206 in the power transmitting circuit 112 outputs a voltage signal Sense_out6 proportional to the value of a current flowing through the switching element 202. A current sensor 207 in the power transmitting circuit 112 outputs a voltage signal Sense_out7 proportional to the value of a current flowing through the switching element 203. A current sensor 208 in the power transmitting circuit 112 outputs a voltage signal Sense_out8 proportional to the value of a current flowing through the switching element 204.

[0026] Capacitors 210 to 213 are connected in parallel to switching elements 201 to 204, respectively. Capacitors 210 to 213 are used to charge and discharge for soft switching while switching elements 201 to 204 are off, respectively. Capacitors 210 to 213 do not need to be connected when the parasitic capacitance of switching elements 201 to 204 is sufficiently large or when hard switching is performed.

[0027] 3 is a diagram showing an example of the configuration of the MCU 114 according to the first embodiment. The MCU 114 includes comparison units 301, 302, 303, and 304, an abnormality determination unit 305, and a clock generation unit 306.

[0028] The comparison unit 301 compares the values ​​of the voltage signals Sense_out1 and Sense_out5. The comparison unit 302 compares the values ​​of the voltage signals Sense_out2 and Sense_out6. The comparison unit 303 compares the values ​​of the voltage signals Sense_out3 and Sense_out7. The comparison unit 304 compares the values ​​of the voltage signals Sense_out4 and Sense_out8.

[0029] The abnormality determination unit 305 determines whether or not the power transmission circuits 111 and 112 are abnormal based on the comparison results of the comparison units 301 to 304, and outputs an alert signal (not shown).

[0030] The clock generating unit 306 generates a clock signal CLK.

[0031] It is preferable that the voltage signals input to the comparison units 301 to 304 are not instantaneous values ​​of the voltage signals Sense_out1 to Sense_out8 but time-averaged values.

[0032] 4(a) to 4(c) are diagrams showing simulation results of the waveform of the current flowing through the current sensor 208 in the power transmission circuits 111 and 112 in the configurations of Figures 1 and 2. In this embodiment, the simulation was performed with the duty ratio of the signals PWM_P and PWM_N being approximately 0.25.

[0033] 4(a) to 4(c), it is assumed that the switching elements 201, 202, 203, and 204 of the power transmitting circuit 111 and the switching elements 201, 202, and 203 of the power transmitting circuit 112 are all operating normally. The simulation is performed by changing only the operation of the switching element 204 in the power transmitting circuit 112. Note that operating normally means that the on-resistance of the switching elements 201 to 204 is a standard value.

[0034] 4(a) is a diagram showing the simulation results of the current waveform when the switching element 204 of the power transmitting circuit 112 is operating normally. As shown in FIG. 4(a), a current flows during the period when the switching element 204 is on, and it can be seen that the current waveforms flowing through the current sensors 208 in the power transmitting circuits 111 and 112 overlap and are exactly the same. When comparing the average current values ​​during the period when current flows through the current sensor 208 of the power transmitting circuit 111 and the current sensor 208 of the power transmitting circuit 112, the ratio is 1.

[0035] 4(b) is a diagram showing the results of a simulation in which the switching element 204 of the power transmitting circuit 112 has a larger on-resistance than the switching element 204 of the power transmitting circuit 111 within the range of manufacturing variation. Current waveform 401 is the waveform of the current flowing to the current sensor 208 of the power transmitting circuit 111. Current waveform 402 is the waveform of the current flowing to the current sensor 208 of the power transmitting circuit 112. It can be seen that the current waveform 402 of the current flowing to the switching element 204 with a large on-resistance is smaller than the current waveform 401 of the current flowing to a normal switching element 204. When the average current value during the period in which the switching element 204 is on and current is flowing is obtained, the average value of current waveform 401 is 13.4 A, and the average value of current waveform 402 is 10.4 A, and it can be seen that the ratio between the two is approximately 0.77.

[0036] 4(c) is a diagram showing the results of a simulation in which an abnormality occurs in the switching element 204 of the power transmitting circuit 112, causing the on-resistance to become abnormally large. Current waveform 403 is the current waveform of the current flowing through the switching element 204 of the power transmitting circuit 111. Current waveform 404 is the current waveform of the current flowing through the switching element 204 of the power transmitting circuit 112. It can be seen that current waveform 404 is always approximately 0 A. Comparing the average values ​​of the current during the period when the current flows through the current sensor 208 of the power transmitting circuit 111 and the current sensor 208 of the power transmitting circuit 112, the ratio is a very small value of less than 1 / 1000.

[0037] 4(a) to 4(c), the comparison unit 304 compares the minimum and maximum values ​​of the average values ​​of the voltage signals Sense_out4 and Sense_out8 acquired by the current sensor 208. The abnormality determination unit 305 detects a decrease in the ratio of the minimum value to the maximum value of the average values ​​of the voltage signals Sense_out4 and Sense_out8, and is able to quickly identify an abnormal power transmitting circuit 112.

[0038] In this simulation, since the operation of only the switching element 204 is changed, the current waveforms of the currents flowing through the current sensors 208 of the power transmitting circuits 111 and 112 are compared. However, in reality, four switching elements 201 to 204 and four current sensors 205 to 208 are implemented in each of the power transmitting circuits 111 and 112. Therefore, the comparison units 301 to 304 perform comparison for each of the current sensors 205 to 208.

[0039] 5 is a flowchart showing the process from when the wireless power transmission system 100 starts up, detects an abnormality, and notifies the user of the abnormality. The process will be described below with reference to the flowchart.

[0040] First, in step S501, the wireless power transmission system 100 is powered on.

[0041] Next, in step S502, the MCU 114 acquires the values ​​of the voltage signals Sense_out1 to Sense_out8 of the current sensors 205 to 208 implemented in the power transmitting circuits 111 and 112 at each sampling period that is sufficiently faster than the period of the frequency of the clock signal CLK.

[0042] Next, in step S503, the MCU 114 obtains the average values ​​of the voltage signals Sense_out1 to Sense_out8 of the current sensors 205 to 208 during the period when the switching elements 201 to 204 are on.

[0043] Next, in step S504, the comparison unit 301 determines whether the ratio of the minimum value to the maximum value of the average values ​​of the voltage signals Sense_out1 and Sense_out5 is greater than a predetermined value. The comparison unit 302 determines whether the ratio of the minimum value to the maximum value of the average values ​​of the voltage signals Sense_out2 and Sense_out6 is greater than a predetermined value. The comparison unit 303 determines whether the ratio of the minimum value to the maximum value of the average values ​​of the voltage signals Sense_out3 and Sense_out7 is greater than a predetermined value. The comparison unit 304 determines whether the ratio of the minimum value to the maximum value of the average values ​​of the voltage signals Sense_out4 and Sense_out8 is greater than a predetermined value. The predetermined value is, for example, 0.6.

[0044] Abnormality determination unit 305 determines whether or not all of comparison units 301 to 304 have determined that the ratio is greater than the predetermined value. If all of comparison units 301 to 304 have determined that the ratio is greater than the predetermined value, the system is normal, and processing proceeds to step S502. If at least one of comparison units 301 to 304 has determined that the ratio is not greater than the predetermined value, the system is abnormal, and processing proceeds to step S505.

[0045] In step S505, the abnormality determination unit 305 determines that either the power transmitting circuit 111 or 112 is abnormal.

[0046] Next, in step S506, the abnormality determination unit 305 determines that the power transmitting circuit 111 or 112 having the switching element corresponding to the voltage signal with the minimum value is abnormal in the determination unit that has determined that the above ratio is not greater than the predetermined value.

[0047] For example, the abnormality determination unit 305 determines that the power transmission circuit 111 is abnormal if the average value of the voltage signal Sense_out1 is smaller than the average value of the voltage signal Sense_out5 and the ratio of the average value of the voltage signal Sense_out1 to the average value of the voltage signal Sense_out5 is not greater than a predetermined value.

[0048] In addition, the abnormality determination unit 305 determines that the power transmission circuit 112 is abnormal if the average value of the voltage signal Sense_out5 is smaller than the average value of the voltage signal Sense_out1 and the ratio of the average value of the voltage signal Sense_out5 to the average value of the voltage signal Sense_out1 is not greater than a predetermined value.

[0049] In addition, the abnormality determination unit 305 determines that the power transmission circuit 111 is abnormal if the average value of the voltage signal Sense_out2 is smaller than the average value of the voltage signal Sense_out6 and the ratio of the average value of the voltage signal Sense_out2 to the average value of the voltage signal Sense_out6 is not greater than a predetermined value.

[0050] In addition, the abnormality determination unit 305 determines that the power transmission circuit 112 is abnormal if the average value of the voltage signal Sense_out6 is smaller than the average value of the voltage signal Sense_out2 and the ratio of the average value of the voltage signal Sense_out6 to the average value of the voltage signal Sense_out2 is not greater than a predetermined value.

[0051] In addition, the abnormality determination unit 305 determines that the power transmission circuit 111 is abnormal if the average value of the voltage signal Sense_out3 is smaller than the average value of the voltage signal Sense_out7 and the ratio of the average value of the voltage signal Sense_out3 to the average value of the voltage signal Sense_out7 is not greater than a predetermined value.

[0052] In addition, the abnormality determination unit 305 determines that the power transmission circuit 112 is abnormal if the average value of the voltage signal Sense_out7 is smaller than the average value of the voltage signal Sense_out3 and the ratio of the average value of the voltage signal Sense_out7 to the average value of the voltage signal Sense_out3 is not greater than a predetermined value.

[0053] In addition, the abnormality determination unit 305 determines that the power transmission circuit 111 is abnormal if the average value of the voltage signal Sense_out4 is smaller than the average value of the voltage signal Sense_out8 and the ratio of the average value of the voltage signal Sense_out4 to the average value of the voltage signal Sense_out8 is not greater than a predetermined value.

[0054] In addition, the abnormality determination unit 305 determines that the power transmission circuit 112 is abnormal if the average value of the voltage signal Sense_out8 is smaller than the average value of the voltage signal Sense_out4 and the ratio of the average value of the voltage signal Sense_out8 to the average value of the voltage signal Sense_out4 is not greater than a predetermined value.

[0055] Next, in step S507, the abnormality determination unit 305 notifies the user that the power transmission circuit 111 or 112 determined in step S506 is abnormal, and urges the user to replace the abnormal power transmission circuit 111 or 112.

[0056] 5, it becomes possible to detect an abnormality in the wireless power transmission system 100 early, identify the abnormal power transmitting circuit 111 or 112, and enable the user to replace the abnormal power transmitting circuit 111 or 112. The predetermined value in step S504 will be described in the second embodiment.

[0057] (Second embodiment) In the first embodiment, a wireless power transmission system 100 has been described in which current sensors 205 to 208 are arranged in series with all of the switching elements 201 to 204. In the second embodiment, a configuration will be described in which current sensors are connected between the power transmitting circuits 111 and 112 and the power transmitting antenna 110. With this configuration, the second embodiment can reduce the number of current sensors compared to the first embodiment.

[0058] Fig. 6 is a diagram showing an example of the configuration of a wireless power transmission system 100 according to the second embodiment. In Fig. 6, the same components as those in Fig. 1 are denoted by the same reference numerals. Fig. 6 is obtained by adding current sensors 601 and 602 to Fig. 1.

[0059] The current sensor 601 is connected between the power transmitting circuit 111 and the power transmitting antenna 110. The current sensor 602 is connected between the power transmitting circuit 112 and the power transmitting antenna 110.

[0060] The current sensor 601 outputs a voltage signal Sense_out9 proportional to the value of a current flowing between the power transmitting circuit 111 and the power transmitting antenna 110 to the MCU 114. The current sensor 602 outputs a voltage signal Sense_out10 proportional to the value of a current flowing between the power transmitting circuit 112 and the power transmitting antenna 110 to the MCU 114.

[0061] The specific configuration of the power transmitting circuits 111 and 112 is the same as that of the power transmitting circuits 111 and 112 in Fig. 2 shown in the first embodiment, except that the current sensors 205, 206, 207, and 208 are removed. The configuration of the MCU 114 is the same as that of the power transmitting circuits 111 and 112 in Fig. 3 shown in the first embodiment, except that the comparison units 302, 303, and 304 are removed.

[0062] Figures 7(a) to (c) are diagrams showing simulation results of current waveforms flowing through current sensors 601 and 602 in the configuration of Figure 6. Note that in Figures 7(a) to (c), simulations were performed when the duty ratio was approximately 0.25, as in the first embodiment.

[0063] As in the simulation of the first embodiment, the switching elements 201, 202, 203, and 204 in the power transmitting circuit 111 and the switching elements 201, 202, and 203 in the power transmitting circuit 112 all operate normally. The simulation was performed by changing only the operation of the switching element 204 in the power transmitting circuit 112.

[0064] 7(a) is a diagram showing the current waveforms of the current sensors 601 and 602 when the switching element 204 in the power transmission circuit 112 is normal. It can be seen that the current waveforms of the current sensors 601 and 602 are roughly sinusoidal waves, and the current waveforms flowing through the current sensors 601 and 602 overlap and are completely identical.

[0065] 7(b) is a diagram showing current waveforms when the on-resistance of the switching element 204 in the power transmitting circuit 112 is large within the range of manufacturing variations. Current waveform 701 is the current waveform of the current flowing through current sensor 601. Current waveform 702 is the current waveform of the current flowing through current sensor 602. It can be seen that the current waveforms 701 and 702 differ from each other only during the period when the switching element 204 is on and current flows. During the period when the switching element 204 is on, the average value of the current waveform 701 is 13.4 A and the average value of the current waveform 702 is 10.4 A, and it can be seen that the ratio between the two is approximately 0.77.

[0066] 7(c) is a diagram showing a current waveform when an abnormality occurs in the switching element 204 in the power transmitting circuit 112, causing the on-resistance to become abnormally large. Current waveform 703 is the current waveform of the current flowing through the current sensor 601. Current waveform 704 is the current waveform of the current flowing through the current sensor 602. It can be seen that the current waveform 704 is approximately 0 only during the period when the switching element 204 is turned on and current is flowing, which is different from the normal case in FIG. 7(a).

[0067] As can be seen from the simulation results of FIGS. 7(a) to 7(c), the number of current sensors 601 and 602 can also be minimized in the configuration shown in this embodiment.

[0068] In this embodiment, an abnormal power transmission circuit can be detected by the flowchart shown in FIG. 5, similar to the first embodiment.

[0069] In step S504, the comparison unit 301 determines whether the ratio of the minimum value to the maximum value of the average value of the voltage signal Sense_out9 from the current sensor 601 and the average value of the voltage signal Sense_out10 from the current sensor 602 is greater than a predetermined value. If the ratio is greater than the predetermined value, the process returns to step S502. If the ratio is not greater than the predetermined value, the process proceeds to step S505, making it possible to quickly identify an abnormality in the power transmitting circuit.

[0070] The abnormality determination unit 305 determines that the power transmission circuit 111 is abnormal if the average value of the voltage signal Sense_out9 is smaller than the average value of the voltage signal Sense_out10 and the ratio of the average value of the voltage signal Sense_out9 to the average value of the voltage signal Sense_out10 is not greater than a predetermined value.

[0071] In addition, the abnormality determination unit 305 determines that the power transmission circuit 112 is abnormal if the average value of the voltage signal Sense_out10 is smaller than the average value of the voltage signal Sense_out9 and the ratio of the average value of the voltage signal Sense_out10 to the average value of the voltage signal Sense_out9 is not greater than a predetermined value.

[0072] In the first and second embodiments, the number of power transmitting circuits 111 and 112 is two. When there are three or more power transmitting circuits, the minimum and maximum average values ​​of the output values ​​of the current sensors are compared, and if the ratio is greater than a predetermined value, it is determined to be normal, and if it is smaller, it is determined to be abnormal.

[0073] 4(b) and 7(b), the on-resistance of the switching element 204 may increase within the range of manufacturing variations. Regarding manufacturing variations, as the number of power transmitting circuits 111 and 112 increases, the ratio of the minimum value to the maximum value among the average values ​​of the output values ​​of each current sensor tends to decrease.

[0074] 8 is a diagram showing current waveforms when there are five power transmission circuits. Current waveform 801 is the current waveform of a current flowing through a normal switching element. Current waveform 802 is the current waveform of a current flowing through a switching element with a large on-resistance within the range of manufacturing variation. Comparing the average values ​​of current waveform 801 and current waveform 802, the average value of current waveform 802 is approximately 0.66 times the average value of current waveform 801.

[0075] Furthermore, when the number of power transmitting circuits is 10, the ratio of the minimum value to the maximum value in the average current waveform is 0.65. Considering a practical wireless power transmission system 100, the appropriate number of power transmitting circuits is approximately 10 at most. Considering that there is a large manufacturing variation depending on the type of FET used as the switching element, the appropriate predetermined value for (minimum value ÷ maximum value) noted in step S504 of Fig. 5 is 0.6.

[0076] (Third embodiment) In the first and second embodiments, the average values ​​of the output values ​​of the current sensors are compared, and if the value obtained by dividing the minimum value by the maximum value is smaller than a predetermined value, an abnormality is determined. In the third embodiment, a configuration is described that can detect an abnormality even when there are multiple abnormal power transmission circuits. Note that the third embodiment, like the first and second embodiments, can also be applied when one of two power transmission circuits is abnormal.

[0077] Fig. 9 is a diagram showing an example of the configuration of a wireless power transmission system 100 according to the third embodiment. The wireless power transmission system 100 in Fig. 9 is obtained by adding a power transmitting circuit 901 and a current sensor 902 to the wireless power transmission system 100 in Fig. 6. The following describes the differences between the third embodiment and the second embodiment.

[0078] The power transmitting device 101 has three power transmitting circuits 111, 112, and 901, and three current sensors 601, 602, and 902. The power transmitting circuits 111, 112, and 901 each convert DC power supplied from a DC power supply 113 into AC power having a frequency of a clock signal CLK generated by an MCU 114, and supply the AC power to the power transmitting antenna 110.

[0079] The power transmitting circuit 901 has a configuration similar to that of the power transmitting circuits 111 and 112 in Fig. 2. The current sensor 902 is connected between the power transmitting circuit 901 and the power transmitting antenna 110, and outputs a voltage signal Sense_out11 proportional to the value of a current flowing between the power transmitting circuit 901 and the power transmitting antenna 110 to the MCU 114.

[0080] Fig. 10 is a diagram showing an example of the configuration of the MCU 114 according to the third embodiment. The MCU 114 includes an abnormality determination unit 305, a clock generation unit 306, an average value calculation unit 1001, and a comparison unit 1002. In Fig. 10, the same components as those in Fig. 3 are denoted by the same reference numerals.

[0081] An average value calculation unit 1001 calculates an average value AVG_ALL of the average values ​​of the voltage signals Sense_out9, Sense_out10, and Sense_out11, and outputs the average value AVG_ALL. A comparison unit 1002 compares the voltage signals Sense_out9, 10, and 11 with the average value AVG_ALL, and outputs the comparison result to an abnormality determination unit 305. The abnormality determination unit 305 determines whether or not an abnormality has occurred based on the comparison result of the comparison unit 1002, and outputs an alert signal (not shown).

[0082] It is preferable that the voltage signals input to the comparison unit 1002 and the average value calculation unit 1001 are not instantaneous values ​​of the voltage signals Sense_out 9, 10, and 11, but values ​​obtained by taking a time average.

[0083] 11 is a diagram showing the results of the simulation. In this simulation, as in the simulation of the first embodiment, the switching elements 201, 202, 203, and 204 in the power transmitting circuit 111 and the switching elements 201, 202, and 203 in the power transmitting circuits 112 and 901 all operate normally.

[0084] Simulations were performed by changing only the operation of the switching element 204 in the power transmitting circuits 112 and 901. The simulation results for the average value of the current flowing through the current sensors 601, 602, and 902 during the period when the switching element 204 is on are shown in Fig. 11. Fig. 11 also shows the average value AVG_ALL of the current value flowing through each of the current sensors 601, 602, and 902.

[0085] First, case 1 is a simulation result when the switching elements 204 in the power transmitting circuits 112 and 901 are operating normally. The average current values ​​flowing through the three current sensors 601, 602, and 902 are the same as the average value AVG_ALL.

[0086] Case 2 is a simulation result when the on-resistance of the switching elements 204 in the power transmitting circuits 112 and 901 is large within the range of manufacturing variations. The average current values ​​flowing through the three current sensors 601, 602, and 902 are at least approximately 0.86 times (=14.8÷17.1) the average value AVG_ALL.

[0087] Case 3 shows the simulation result when an abnormality occurs in the switching elements 204 in the power transmitting circuits 112 and 901, causing the on-resistance to be abnormally large. Here, the simulation result is shown for a case where the on-resistance of the switching element 204 in the power transmitting circuit 901 is larger than that of the switching element 204 in the power transmitting circuit 112. Compared with the average value AVG_ALL, the average current value of the current sensor 602 is approximately 0.43 times, and the average current value of the current sensor 902 is 0.24 times.

[0088] FIG. 12 is a flowchart showing a processing method of the wireless power transmission system 100 according to the third embodiment.

[0089] First, in step S1201, the wireless power transmission system 100 is powered on.

[0090] Next, in step S1202, the MCU 114 acquires the values ​​of the voltage signals Sense_out9, 10, and 11 of the current sensors 601, 602, and 902 at each sampling period that is sufficiently faster than the period of the frequency of the clock signal CLK.

[0091] Next, in step S1203, the MCU 114 acquires the average values ​​of the voltage signals Sense_out9, 10, and 11 of the current sensors 601, 602, and 902 during the period when the switching elements 201 to 204 are on.

[0092] Next, in step S1204, the average value calculation unit 1001 calculates an average value AVG_ALL of the average values ​​of the voltage signals Sense_out9, Sense_out10, and Sense_out11.

[0093] Next, in step S1205, the comparison unit 1002 determines whether the ratio of the average value of the voltage signal Sense_out9 to the average value AVG_ALL is greater than a predetermined value.The comparison unit 1002 then determines whether the ratio of the average value of the voltage signal Sense_out10 to the average value AVG_ALL is greater than a predetermined value.The comparison unit 1002 then determines whether the ratio of the average value of the voltage signal Sense_out11 to the average value AVG_ALL is greater than a predetermined value.

[0094] The abnormality determination unit 305 determines whether all of the ratios of the average values ​​of the voltage signals Sense_out9, 10, and 11 are greater than a predetermined value. If all of the ratios of the average values ​​of the voltage signals Sense_out9, 10, and 11 are greater than the predetermined value, the system is normal, and the process returns to step S1202. If at least one of the ratios of the average values ​​of the voltage signals Sense_out9, 10, and 11 is not greater than the predetermined value, the system is abnormal, and the process proceeds to step S1206.

[0095] In step S1206, the abnormality determination unit 305 determines that one of the power transmission circuits 111, 112, and 901 is abnormal.

[0096] Next, in step S1207, the abnormality determination unit 305 determines that one or more of the power transmitting circuits 111, 112, or 901 including the switching element corresponding to the voltage signal having the smallest value determined to be not greater than the predetermined value is abnormal.

[0097] For example, the abnormality determination unit 305 determines that the power transmitting circuit 111 is abnormal if the ratio of the average value of the voltage signal Sense_out9 to the average value AVG_ALL is not greater than a predetermined value.

[0098] Furthermore, the abnormality determination unit 305 determines that the power transmitting circuit 112 is abnormal if the ratio of the average value of the voltage signal Sense_out10 to the average value AVG_ALL is not greater than a predetermined value.

[0099] Furthermore, the abnormality determination unit 305 determines that the power transmitting circuit 901 is abnormal if the ratio of the average value of the voltage signal Sense_out11 to the average value AVG_ALL is not greater than a predetermined value.

[0100] Next, in step S1208, the abnormality determination unit 305 notifies the user that the power transmission circuit 111, 112, or 901 determined in step S1207 is abnormal, and urges the user to replace the abnormal power transmission circuit 111, 112, or 901.

[0101] According to this embodiment, the flowchart of FIG. 12 enables early detection of an abnormality in the wireless power transmission system 100, identification of the abnormal power transmission circuit 111, 112 or 901, and the user to replace the abnormal power transmission circuit 111, 112 or 901.

[0102] As in the first and second embodiments, as the number of power transmitting circuits increases, the value of the average output value of each current sensor divided by AVG_ALL tends to decrease even within the range of manufacturing variations. For example, when the number of power transmitting circuits is 10, the value of the average output value divided by AVG_ALL becomes 0.72 times.

[0103] Considering a practical wireless power transmission system 100, the appropriate number of power transmission circuits is a maximum of about 10. Considering that there is a large manufacturing variation depending on the type of FET used as a switching element, the appropriate predetermined value for "average output value of each current sensor ÷ AVG_ALL" in step S1205 of Fig. 12 is 0.7 times.

[0104] In the first to third embodiments, the switching element refers to a MOSFET or a GAN-FET.

[0105] In the first to third embodiments, the simulation results are shown as current waveforms, but the output value of the current sensor is, for example, an analog voltage value proportional to the current value. The voltage value can be converted into digital data by an AD converter in the MCU 114 and processed.

[0106] In the first to third embodiments, the sampling period for acquiring the output value of the current sensor is set to a period shorter than approximately 1 / 40 times the period of the frequency of the clock signal CLK, thereby making it possible to acquire an accurate output value.

[0107] Furthermore, in the first to third embodiments, simulation results are shown for the case where the power transmission circuit is a full-bridge circuit, but the power transmission circuit can also be applied to other circuit configurations such as a push-pull circuit or a half-bridge circuit.

[0108] As described above, according to the first to third embodiments, the power transmitting device 101 can detect an abnormal state of the power transmitting circuit with a simple configuration.

[0109] It should be noted that the above-described embodiments merely illustrate specific examples of implementing the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these embodiments. In other words, the present disclosure can be implemented in various forms without departing from its technical concept or main features.

[0110] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) A transmitting antenna; a plurality of power transmitting circuits, each including a switching element, converting DC power into AC power and supplying the AC power to the power transmitting antenna; a plurality of current detection units that output signals based on values ​​of currents flowing between the plurality of power transmission circuits and the power transmission antenna; an abnormality determination unit that determines whether or not the plurality of power transmission circuits are abnormal based on the signal; A power transmission device comprising: (Configuration 2) 2. The power transmitting device according to configuration 1, wherein the plurality of current detection units are provided in the plurality of power transmitting circuits, respectively, and are connected in series to the switching elements. (Configuration 3) 2. The power transmitting device according to configuration 1, wherein the plurality of current detection units are connected between the plurality of power transmitting circuits and the power transmitting antenna, respectively. (Configuration 4) The power transmission device according to any one of configurations 1 to 3, characterized in that the abnormality determination unit determines that the power transmission circuit corresponding to the minimum value is abnormal if the ratio of the minimum value to the maximum value among the average values ​​of each of the multiple signals output by the multiple detection units is not greater than a predetermined value. (Configuration 5) The power transmission device according to configuration 1 or 3, characterized in that the abnormality determination unit determines that the power transmission circuit corresponding to the current detection unit is abnormal when a ratio of the average value of the signal output by the current detection unit to the average value of each of the average values ​​of the multiple signals output by the multiple current detection units is not greater than a predetermined value. (Configuration 6) The plurality of power transmission circuits include: a first power transmitting circuit including a first switching element, converting DC power into first AC power, and supplying the first AC power to the power transmitting antenna; a second power transmitting circuit including a second switching element, converting the DC power into second AC power, and supplying the second AC power to the power transmitting antenna; The plurality of current detection units include a first current detection unit that outputs a first signal based on a value of a current flowing between the first power transmitting circuit and the power transmitting antenna; a second current detection unit that outputs a second signal based on a value of a current flowing between the second power transmitting circuit and the power transmitting antenna, The power transmission device according to configuration 1, wherein the abnormality determination unit determines whether or not the first power transmission circuit is abnormal based on the first signal, and determines whether or not the second power transmission circuit is abnormal based on the second signal. (Configuration 7) the first current detection unit is provided in the first power transmission circuit and is connected in series to the first switching element; 7. The power transmitting device according to configuration 6, wherein the second current detection unit is provided in the second power transmitting circuit and is connected in series to the second switching element. (Configuration 8) The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; The power transmitting device according to configuration 7, characterized in that it determines that the second power transmitting circuit is abnormal if the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value. (Configuration 9) the first power transmitting circuit includes a third switching element, a fourth switching element, a fifth switching element, a third current detecting unit, a fourth current detecting unit, and a fifth current detecting unit; the third current detection unit is connected in series to the third switching element and outputs a third signal based on a value of a current flowing through the third switching element; the fourth current detection unit is connected in series to the fourth switching element and outputs a fourth signal based on a value of a current flowing through the fourth switching element; the fifth current detection unit is connected in series to the fifth switching element and outputs a fifth signal based on a value of a current flowing through the fifth switching element; the second power transmitting circuit includes a sixth switching element, a seventh switching element, an eighth switching element, a sixth current detection unit, a seventh current detection unit, and an eighth current detection unit; the sixth current detection unit is connected in series to the sixth switching element and outputs a sixth signal based on a value of a current flowing through the sixth switching element; the seventh current detection unit is connected in series to the seventh switching element and outputs a seventh signal based on a value of a current flowing through the seventh switching element; the eighth current detection unit is connected in series to the eighth switching element and outputs an eighth signal based on a value of a current flowing through the eighth switching element; The power transmission device according to configuration 7, wherein the abnormality determination unit determines whether or not the first power transmission circuit is abnormal based on the first signal, the third signal, the fourth signal, and the fifth signal, and determines whether or not the second power transmission circuit is abnormal based on the second signal, the sixth signal, the seventh signal, and the eighth signal. (Configuration 10) The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the third signal is smaller than the average value of the sixth signal and the ratio of the average value of the sixth signal to the average value of the third signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the sixth signal is smaller than the average value of the third signal and the ratio of the average value of the sixth signal to the average value of the third signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the fourth signal is smaller than the average value of the seventh signal and the ratio of the average value of the seventh signal to the average value of the fourth signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the seventh signal is smaller than the average value of the fourth signal and the ratio of the average value of the seventh signal to the average value of the fourth signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the fifth signal is smaller than the average value of the eighth signal and the ratio of the average value of the eighth signal to the average value of the fifth signal is not greater than a predetermined value; The power transmitting device according to configuration 9, characterized in that if the average value of the eighth signal is smaller than the average value of the fifth signal and the ratio of the average value of the eighth signal to the average value of the fifth signal is not greater than a predetermined value, it is determined that the second power transmitting circuit is abnormal. (Configuration 11) 11. The power transmitting device according to configuration 8 or 10, wherein the predetermined value is 0.6. (Configuration 12) the first current detection unit is connected between the first power transmitting circuit and the power transmitting antenna, 7. The power transmitting device according to configuration 6, wherein the second current detection unit is connected between the second power transmitting circuit and the power transmitting antenna. (Configuration 13) The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; The power transmitting device according to configuration 12, characterized in that if the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value, it is determined that the second power transmitting circuit is abnormal. (Configuration 14) 14. The power transmitting device according to configuration 13, wherein the predetermined value is 0.6. (Configuration 15) a third power transmitting circuit including a ninth switching element, converting the DC power into third AC power and supplying the third AC power to the power transmitting antenna; a ninth current detection unit connected between the third power transmitting circuit and the power transmitting antenna and configured to output a ninth signal based on a value of a current flowing between the third power transmitting circuit and the power transmitting antenna, 13. The power transmitting device according to configuration 12, wherein the abnormality determination unit determines whether or not the third power transmitting circuit is abnormal based on the ninth signal. (Configuration 16) The abnormality determination unit determining that the first power transmitting circuit is abnormal when a ratio of the average value of the first signal to an average value of the first signal, the average value of the second signal, and the average value of the ninth signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when a ratio of the average value of the second signal to an average value of the first signal, the average value of the second signal, and the average value of the ninth signal is not greater than a predetermined value; The power transmitting device according to configuration 15, characterized in that if the ratio of the average value of the ninth signal to the average value of the first signal, the average value of the second signal, and the average value of the ninth signal is not greater than a predetermined value, it is determined that the third power transmitting circuit is abnormal. (Configuration 17) 17. The power transmitting device according to configuration 16, wherein the predetermined value is 0.7. (Configuration 18) the first power transmitting circuit has a third switching element, a fourth switching element, and a fifth switching element; 18. The power transmitting device according to any one of configurations 12 to 17, wherein the second power transmitting circuit has a sixth switching element, a seventh switching element, and an eighth switching element. (Configuration 19) the first, third to fifth switching elements form a first full-bridge circuit; The power transmitting device according to any one of configurations 9, 10 and 18, wherein the second and sixth to eighth switching elements form a second full-bridge circuit. (Configuration 20) The power transmitting device according to any one of configurations 1 to 19, a power receiving device; The power receiving device is a power receiving antenna coupled to the power transmitting antenna; a power receiving circuit that converts AC power received by the power receiving antenna into DC power. (Method 1) A transmitting antenna; a plurality of power transmitting circuits, each of which includes a switching element, converts DC power into AC power, and supplies the AC power to the power transmitting antenna, the method comprising: a current detection step of outputting a signal based on a current value flowing between each of the plurality of power transmitting circuits and the power transmitting antenna; an abnormality determination step of determining whether or not the plurality of power transmission circuits are abnormal based on the signal; A processing method for a power transmission device, comprising: [Explanation of symbols]

[0111] 100 Wireless power transmission system; 101 Power transmission unit; 102 Power receiving unit; 103 Load; 110 Power transmission antenna; 111, 112, 801 Power transmission circuit; 113 DC power supply; 114 MCU; 120 Power receiving antenna; 121 Power receiving circuit; 201, 202, 203, 204 Switching element; 205, 206, 207, 208, 501, 502, 802 Current sensor; 209 Gate drive circuit; 210, 211, 212, 213 Capacitor

Claims

1. A transmitting antenna; a plurality of power transmitting circuits, each including a switching element, converting DC power into AC power and supplying the AC power to the power transmitting antenna; a plurality of current detection units that output signals based on values ​​of currents flowing between the plurality of power transmission circuits and the power transmission antenna; an abnormality determination unit that determines whether or not the plurality of power transmission circuits are abnormal based on the signal; A power transmission device comprising:

2. The power transmitting device according to claim 1 , wherein the plurality of current detecting units are provided in the plurality of power transmitting circuits, respectively, and are connected in series to the switching element.

3. The power transmitting device according to claim 1 , wherein the plurality of current detection units are connected between the plurality of power transmitting circuits and the power transmitting antenna, respectively.

4. The power transmission device according to claim 1, characterized in that the abnormality determination unit determines that the power transmission circuit corresponding to the minimum value is abnormal if the ratio of the minimum value to the maximum value among the average values ​​of each of the multiple signals output by the multiple detection units is not greater than a predetermined value.

5. The power transmission device according to claim 1, characterized in that the abnormality determination unit determines that the power transmission circuit corresponding to the current detection unit is abnormal if the ratio of the average value of the signal output by the current detection unit to the average value of the average values ​​of each of the multiple signals output by the multiple current detection units is not greater than a predetermined value.

6. The plurality of power transmission circuits include: a first power transmitting circuit including a first switching element, converting DC power into first AC power, and supplying the first AC power to the power transmitting antenna; a second power transmitting circuit including a second switching element, converting the DC power into second AC power, and supplying the second AC power to the power transmitting antenna; The plurality of current detection units include a first current detection unit that outputs a first signal based on a value of a current flowing between the first power transmitting circuit and the power transmitting antenna; a second current detection unit that outputs a second signal based on a value of a current flowing between the second power transmitting circuit and the power transmitting antenna, The power transmission device according to claim 1, characterized in that the abnormality determination unit determines whether or not the first power transmission circuit is abnormal based on the first signal, and determines whether or not the second power transmission circuit is abnormal based on the second signal.

7. the first current detection unit is provided in the first power transmission circuit and is connected in series to the first switching element; The power transmitting device according to claim 6 , wherein the second current detection unit is provided in the second power transmitting circuit and is connected in series to the second switching element.

8. The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; The power transmission device according to claim 7, characterized in that if the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value, it is determined that the second power transmission circuit is abnormal.

9. the first power transmitting circuit includes a third switching element, a fourth switching element, a fifth switching element, a third current detecting unit, a fourth current detecting unit, and a fifth current detecting unit; the third current detection unit is connected in series to the third switching element and outputs a third signal based on a value of a current flowing through the third switching element; the fourth current detection unit is connected in series to the fourth switching element and outputs a fourth signal based on a value of a current flowing through the fourth switching element; the fifth current detection unit is connected in series to the fifth switching element and outputs a fifth signal based on a value of a current flowing through the fifth switching element; the second power transmitting circuit includes a sixth switching element, a seventh switching element, an eighth switching element, a sixth current detecting unit, a seventh current detecting unit, and an eighth current detecting unit; the sixth current detection unit is connected in series to the sixth switching element and outputs a sixth signal based on a value of a current flowing through the sixth switching element; the seventh current detection unit is connected in series to the seventh switching element and outputs a seventh signal based on a value of a current flowing through the seventh switching element; the eighth current detection unit is connected in series to the eighth switching element and outputs an eighth signal based on a value of a current flowing through the eighth switching element; The power transmission device according to claim 7, characterized in that the abnormality determination unit determines whether or not the first power transmission circuit is abnormal based on the first signal, the third signal, the fourth signal, and the fifth signal, and determines whether or not the second power transmission circuit is abnormal based on the second signal, the sixth signal, the seventh signal, and the eighth signal.

10. The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the third signal is smaller than the average value of the sixth signal and the ratio of the average value of the sixth signal to the average value of the third signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the sixth signal is smaller than the average value of the third signal and the ratio of the average value of the sixth signal to the average value of the third signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the fourth signal is smaller than the average value of the seventh signal and the ratio of the average value of the seventh signal to the average value of the fourth signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when the average value of the seventh signal is smaller than the average value of the fourth signal and the ratio of the average value of the seventh signal to the average value of the fourth signal is not greater than a predetermined value; determining that the first power transmitting circuit is abnormal when the average value of the fifth signal is smaller than the average value of the eighth signal and the ratio of the average value of the eighth signal to the average value of the fifth signal is not greater than a predetermined value; The power transmission device according to claim 9, characterized in that if the average value of the eighth signal is smaller than the average value of the fifth signal and the ratio of the average value of the eighth signal to the average value of the fifth signal is not greater than a predetermined value, it is determined that the second power transmission circuit is abnormal.

11. The power transmitting device according to claim 8, wherein the predetermined value is 0.

6.

12. the first current detection unit is connected between the first power transmitting circuit and the power transmitting antenna, The power transmitting device according to claim 6 , wherein the second current detection unit is connected between the second power transmitting circuit and the power transmitting antenna.

13. The abnormality determination unit determining that the first power transmitting circuit is abnormal when the average value of the first signal is smaller than the average value of the second signal and the ratio of the average value of the first signal to the average value of the second signal is not greater than a predetermined value; The power transmission device according to claim 12, characterized in that if the average value of the second signal is smaller than the average value of the first signal and the ratio of the average value of the second signal to the average value of the first signal is not greater than a predetermined value, it is determined that the second power transmission circuit is abnormal.

14. 14. The power transmitting device according to claim 13, wherein the predetermined value is 0.

6.

15. a third power transmitting circuit including a ninth switching element, converting the DC power into third AC power and supplying the third AC power to the power transmitting antenna; a ninth current detection unit connected between the third power transmitting circuit and the power transmitting antenna and configured to output a ninth signal based on a value of a current flowing between the third power transmitting circuit and the power transmitting antenna, The power transmitting device according to claim 12 , wherein the abnormality determination unit determines whether or not the third power transmitting circuit is abnormal based on the ninth signal.

16. The abnormality determination unit determining that the first power transmitting circuit is abnormal when a ratio of the average value of the first signal to an average value of the first signal, the average value of the second signal, and the average value of the ninth signal is not greater than a predetermined value; determining that the second power transmitting circuit is abnormal when a ratio of the average value of the second signal to an average value of the first signal, the second signal, and the ninth signal is not greater than a predetermined value; The power transmission device according to claim 15, characterized in that if the ratio of the average value of the ninth signal to the average value of the first signal, the average value of the second signal, and the average value of the ninth signal is not greater than a predetermined value, it is determined that the third power transmission circuit is abnormal.

17. 17. The power transmitting device according to claim 16, wherein the predetermined value is 0.

7.

18. the first power transmitting circuit includes a third switching element, a fourth switching element, and a fifth switching element; 13. The power transmitting device according to claim 12, wherein the second power transmitting circuit has a sixth switching element, a seventh switching element, and an eighth switching element.

19. the first, third to fifth switching elements form a first full-bridge circuit; 10. The power transmitting device according to claim 9, wherein the second and sixth to eighth switching elements form a second full-bridge circuit.

20. The power transmitting device according to any one of claims 1 to 19, a power receiving device; The power receiving device is a power receiving antenna coupled to the power transmitting antenna; a power receiving circuit that converts AC power received by the power receiving antenna into DC power.

21. A transmitting antenna; a plurality of power transmitting circuits, each of which includes a switching element, converts DC power into AC power, and supplies the AC power to the power transmitting antenna, the method comprising: a current detection step of outputting a signal based on a current value flowing between each of the plurality of power transmitting circuits and the power transmitting antenna; an abnormality determination step of determining whether or not the plurality of power transmission circuits are abnormal based on the signal; A processing method for a power transmission device, comprising:

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