Power transmission equipment

Abstract

To prevent failures of each part due to short-circuit of a semiconductor element in a power transmission device.SOLUTION: A power transmission device 100 is for supplying power contactlessly to a power receiving device 200 having a power receiving coil 212. The power transmission device 100 includes a power transmission coil 112, a power transmission resonant circuit 110 including a power transmission resonant capacitor 114 connected in parallel with the power transmission coil, a tertiary resonant circuit 310, and a power transmission control unit 180 that controls a tertiary resonant switching element. The tertiary resonant circuit 310 includes a tertiary coil 312, a tertiary resonant capacitor 314 connected in parallel with the tertiary coil, and a tertiary resonance switching element 316 connected in parallel with the tertiary coil. The tertiary resonance switching element switches resonant and non-resonant states of the tertiary resonance circuit. The power transmission control unit shorts the tertiary resonance switching element to switch the tertiary coil and the tertiary resonant capacitor to the non-resonant state when switching from a power energized state in which power is supplied to the power receiving device to a standby state in which power is not supplied to the power receiving device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power transmitting device. [Background technology]

[0002] A power transmitting device is known in which, in a facing state where the power transmitting coil faces the power receiving coil, the input impedance is reduced to supply power from the power transmitting device to the power receiving device, and, in a non-facing state, the input impedance of the power transmitting resonant circuit is increased to suppress the supply of current from the power transmitting device to the power receiving device (for example, Patent Document 1). In this power transmitting device, a semiconductor element such as a bidirectional switch is used as a switching circuit, and the magnitude of the input impedance of the power transmitting resonant circuit is switched by switching the semiconductor element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-23094 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional configuration, for example, a protection circuit may be required to prevent a so-called short-circuit fault, in which a semiconductor element fails in a conductive state, from inducing a failure in other components of the power transmitting device, which can lead to problems such as an increase in the number of components and an increase in size of the power transmitting device. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] According to one embodiment of the present disclosure, there is provided a power transmitting device (100, 100b) that contactlessly supplies power to a power receiving device (200) having a power receiving coil (212). The power transmitting device includes: a power transmitting resonant circuit (110) including a power transmitting coil (112) magnetically coupled to the power receiving coil and a power transmitting resonant capacitor (114) connected in series to the power transmitting coil; a tertiary resonant circuit (310, 310b) including a tertiary coil (312) magnetically coupled to the power transmitting coil and the power receiving coil, a tertiary resonant capacitor (314) connected in parallel with the tertiary coil, and a tertiary resonance switching element (316) connected in parallel with the tertiary coil, the tertiary resonance switching element switching between a resonant state and a non-resonant state of the tertiary resonant circuit by switching between an open state and a short state of the tertiary resonance switching element; and a power transmitting control unit (180) that controls the tertiary resonance switching element. When switching from a power-on state in which power is supplied to the power receiving device to a standby state in which power is not supplied to the power receiving device, the power transmission control unit short-circuits the tertiary resonance switching element to switch the tertiary coil and the tertiary resonance capacitor to a non-resonant state.

[0007] According to this power transmitting device, the tertiary coil and the tertiary resonant capacitor can be brought into a non-resonant state by short-circuiting the tertiary resonance switching element. Therefore, even if a short-circuit fault occurs in the tertiary resonance switching element, damage to other components of the power transmitting device can be suppressed or prevented without providing a protection circuit, etc. Therefore, an increase in the number of components and an increase in size of the power transmitting device can be suppressed or prevented. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram showing a power transmitting device according to a first embodiment. [Figure 2] FIG. 10 is a schematic configuration diagram showing a power transmitting device according to a second embodiment. [Figure 3] FIG. 10 is a schematic configuration diagram showing a power transmitting device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: 1, the contactless power supply system includes a power transmission device 100 according to the first embodiment, and a power receiving device 200 to which power is supplied contactlessly from the power transmission device 100. The power receiving device 200 is mounted in various devices that operate using electric power, such as electronic devices and electric vehicles. The power receiving device 200 includes a power receiving resonant circuit 210, a power receiving circuit 220, and a battery 230.

[0010] The power receiving resonant circuit 210 has a power receiving coil 212 and a power receiving resonant capacitor 214 connected in series to the power receiving coil 212. For example, a primary-series-secondary-series capacitor resonant system (also called the "SS system") is applied to the power receiving resonant circuit 210. The power receiving resonant circuit 210 is a resonant circuit that obtains AC power induced in the power receiving coil 212 in a state of resonant coupling in which the power receiving coil 212 and the power transmitting coil 112 are magnetically coupled.

[0011] The power receiving circuit 220 converts the AC power output from the power receiving resonant circuit 210 into DC power. The power receiving circuit 220 has, for example, a filter circuit, a rectifier circuit that converts the AC power into DC power, and a power conversion circuit that converts the AC power into DC power suitable for charging the battery 230. The DC power output from the power receiving circuit 220 can be used for charging the battery 230, etc.

[0012] The power transmitting device 100 includes a power transmitting resonant circuit 110, a tertiary resonant circuit 310, and a power transmitting control unit 180. In the example of Fig. 1, the power transmitting device 100 further includes a current sensor 118, a power supply circuit 140, a power transmitting circuit 130, and a magnetic flux detection unit 170. The power supply circuit 140 is, for example, an AC / DC converter circuit, and converts AC power from an AC power source such as a system power supply into DC power and supplies it to the power transmitting circuit 130. The power transmitting circuit 130 is a device including an inverter and the like that converts DC power supplied from the power supply circuit 140 into AC power of a predetermined operating frequency (angular frequency) and supplies it to the power transmitting resonant circuit 110. The power transmitting circuit 130 may further include a rectifier circuit, a filter circuit, and the like.

[0013] The power transmitting resonant circuit 110 transmits AC power induced in the power transmitting coil 112 by utilizing the electromagnetic induction phenomenon to the power receiving resonant circuit 210 of the power receiving device 200. The power transmitting resonant circuit 110 has the power transmitting coil 112 and a power transmitting resonant capacitor 114 connected in series to the power transmitting coil 112.

[0014] The power transmitting resonant capacitor 114 is a resonant capacitor for resonating the power supplied to the power transmitting coil 112. In this embodiment, the power transmitting resonant capacitor 114 has a first capacitor 114t, a power transmitting switching element 116 connected in series to the first capacitor 114t, and a second capacitor 114s connected in parallel to the first capacitor 114t and the power transmitting switching element 116. The power transmitting resonant capacitor 114 is a variable capacitor whose capacitance can be changed by turning the power transmitting switching element 116 on and off.

[0015] The power transmission switching element 116 functions as a current switching unit for switching the magnitude of the current flowing through the power transmission resonant circuit 110. In this embodiment, the power transmission switching element 116 is a semiconductor element that controls current, such as an IGBT, a MOSFET, or a FET, and switches the input impedance Z1 of the power transmission resonant circuit 110 under the control of the power transmission control unit 180. As shown in FIG. 1 , in this embodiment, the power transmission switching element 116 is configured as a bidirectional switch. The method by which the current switching unit switches the magnitude of the current flowing through the power transmission resonant circuit 110 is not limited to switching the value of the input impedance, and may be methods such as switching capacitance or turning on and off the power supply. Note that the power transmission switching element 116 is not limited to being a bidirectional switch, and may be a unidirectional switch.

[0016] The capacitance of the second capacitor 114s is set to a value smaller than the capacitance of the first capacitor 114t. The first capacitor 114t is connected in parallel to the second capacitor 114s when the power transmission switching element 116 is short-circuited (on), and is open when the power transmission switching element 116 is open (off). Therefore, the capacitance of the power transmission resonant capacitor 114 is the capacitance of the second capacitor 114s when the power transmission switching element 116 is open, and is the sum of the capacitance of the first capacitor 114t and the capacitance of the second capacitor 114s when the power transmission switching element 116 is short-circuited.

[0017] The sum of the capacitance of the first capacitor 114t and the capacitance of the second capacitor 114s is set using a predetermined angular frequency of the operating frequency at which the power transmitting resonant capacitor 114 and the power transmitting coil 112 resonate. The capacitance of the power transmitting resonant capacitor 114 when power is being fed to the power receiving device 200 can be set to a relatively small value because it only needs to be set so as to resonate with the self-inductance of the power transmitting coil 112. Therefore, the capacitance of the first capacitor 114t and the capacitance of the second capacitor 114s used in the power transmitting resonant capacitor 114 can be set to a relatively small value, preventing the capacitors from becoming larger. The capacitance of the second capacitor 114s determines the standby current that flows through the power transmitting coil 112 when power is not being fed.

[0018] The current sensor 118 detects the value I1 of a current flowing through the power transmitting resonant circuit 110. The detection result of the current sensor 118 is used to determine whether the power transmitting coil 112 and the power receiving coil 212 are in an opposing state or a non-opposing state. Note that, because the voltage applied to the power transmitting coil 112 also changes in the same way as the current, a voltage sensor for detecting the value V1 of the voltage applied to the power transmitting coil 112 may be provided instead of the current sensor 118. Also, instead of the current sensor 118, a magnetic flux detection element such as a magnetic sensor or coil for detecting a magnetic field (magnetic flux) in the vicinity of the power transmitting coil 112 may be provided. For example, a shunt resistor or a relatively small inductance such as wiring inductance may be provided instead of or in addition to the current sensor 118, and the voltage generated in the power transmitting resonant capacitor 114 due to the current flowing through the power transmitting coil 112 may be detected instead of or in addition to the current value.

[0019] As shown in FIG. 1, the tertiary resonant circuit 310 is a parallel resonant circuit of a so-called primary-parallel-secondary-series type (also referred to as a "PS type") in which a tertiary coil 312 and a tertiary resonant capacitor 314 are connected in parallel. In this embodiment, the tertiary resonant circuit 310 is a circuit independent of the power transmitting resonant circuit 110. The tertiary resonant circuit 310 includes a tertiary coil 312, a tertiary resonant capacitor 314 which is a resonant capacitor connected in parallel to the tertiary coil 312, and a tertiary resonance switching element 316 connected in parallel to the tertiary coil 312. The tertiary resonant circuit 310 is arranged such that the tertiary coil 312 is magnetically coupled to both the power transmitting coil 112 and the power receiving coil 212. In FIG. 1, two parallel lines indicate that the coils are magnetically coupled to each other.

[0020] In this embodiment, the tertiary resonant circuit 310 is provided with a current sensor 318. The current sensor 318 detects the value of a current flowing through the tertiary resonant circuit 310. The detection result of the current sensor 318 is used to determine whether the power transmitting coil 112 and the power receiving coil 212 are facing each other or not. Note that, instead of the current sensor 318, a voltage sensor that detects the value of a voltage applied to the tertiary resonant circuit 310, a magnetic sensor that detects a magnetic flux generated in the tertiary resonant circuit 310, or the like may be used. In this embodiment, an example has been shown in which the power transmitting device 100 is provided with both the current sensor 118 and the current sensor 318, but only one of the current sensor 118 and the current sensor 318 may be provided.

[0021] Tertiary resonance switching element 316 is a semiconductor element that controls current, such as an IGBT, MOSFET, or FET, and switches between a resonant state and a non-resonant state between tertiary coil 312 and tertiary resonant capacitor 314 by changing the impedance between tertiary coil 312 and tertiary resonant capacitor 314. Tertiary resonance switching element 316 is controlled by power transmission control unit 180. Note that in the present disclosure, the resonant state is not limited to a state in which the resonant capacitor and the coil are resonating, but also includes a state in which the resonant capacitor and the coil can resonate in a circuit configuration.

[0022] For example, if the tertiary resonance switching element 316 is connected in series with the tertiary coil 312 and the tertiary resonant capacitor 314, and the tertiary resonance switching element 316, which is a semiconductor element, fails while remaining in a conductive state due to being stuck closed or the like, a so-called short-circuit failure occurs, the tertiary resonant circuit 310 will be fixed in a resonant state. In this case, for example, if another power transmitting coil 112 is present near one power transmitting coil 112 and the other power transmitting coil 112 starts supplying power to the power receiving coil 212, the magnetic flux generated in the other power transmitting coil 112 may be amplified by the tertiary resonant circuit 310. This may result in an increase in leakage electromagnetic fields (EMF) in the tertiary resonant circuit 310, an increase in voltage in the tertiary coil 312, or the like. Furthermore, if another power transmission coil 112 is magnetically coupled to one power transmission coil 112 in this state, the voltage applied to that power transmission coil 112 will increase, and a voltage higher than the rated voltage will be applied to semiconductor elements such as the power transmission switching element 116, which may induce a short-circuit failure.

[0023] In this embodiment, when the tertiary resonance switching element 316 is short-circuited (ON), the tertiary coil 312 and the tertiary resonant capacitor 314 can be in a non-resonant state, and when the tertiary resonance switching element 316 is open (OFF), the tertiary coil 312 and the tertiary resonant capacitor 314 can be in a resonant state. Therefore, even if a short-circuit failure occurs in the tertiary resonance switching element 316, for example, the tertiary resonant circuit 310 is fixed in a non-resonant state, and therefore, failures in various parts of the power transmitting device 100, such as a short-circuit failure in the power transmission switching element 116, can be suppressed or prevented.

[0024] The magnetic flux detection unit 170 detects magnetic flux generated near the power transmitting coil 112. In the power transmitting device 100, an AC voltage supplied from the power transmitting circuit 130 is applied between the terminals of the power transmitting coil 112, and magnetic flux is generated according to the AC standby current flowing through the power transmitting coil 112. When the power receiving device 200 approaches the power transmitting device 100 in this state and they become facing each other, magnetic coupling occurs between the power receiving coil 212 and the power transmitting coil 112, and as the degree of coupling increases, the power receiving coil 212 generates induced magnetic flux. The induced magnetic flux increases the magnetic flux linking the power transmitting coil 112. The detection result by the magnetic flux detection unit 170 is output to the power transmission control unit 180.

[0025] The power transmission control unit 180 is a microcomputer having a CPU and memory (not shown) or a logic circuit. The power transmission control unit 180 acquires the detection results of the magnetic flux detection unit 170, the current sensor 118, and the current sensor 318, and controls the on / off of the power transmission switching element 116 and the tertiary resonance switching element 316 according to the acquired results.

[0026] When the power transmission control unit 180 detects that the magnetic flux in the vicinity of the power transmission coil 112 has increased to or above a certain value, for example, by comparing the detection result of the magnetic flux interlinking the power transmission coil 112 by the magnetic flux detection unit 170 with a predetermined threshold value, the power transmission control unit 180 determines that the power transmission coil 112 and the power receiving coil 212 are in an opposing state.

[0027] When the power transmission control unit 180 determines that the power transmitting device 100 is in the opposing state, it switches the power transmitting device 100 to a conducting state. More specifically, the power transmitting control unit 180 shorts the power transmitting switching element 116 to increase the capacitance of the power transmitting resonant capacitor 114, thereby switching the input impedance Z1 of the power transmitting resonant circuit 110 to a small value and switching the state to a state in which a large current for power supply flows through the power transmitting resonant circuit 110, and also opens the tertiary resonance switching element 316 to switch the tertiary coil 312 and the tertiary resonant capacitor 314 to a resonant state. As a result, the power transmitting device 100 is in a conducting state, and power supply from the power transmitting coil 112 to the power receiving coil 212 begins. When the power receiving coil 212 and the power transmitting coil 112 are magnetically coupled, the power receiving resonant circuit 210 receives AC power induced in the power receiving coil 212 from the power transmitting device 100 in a wireless manner.

[0028] The power transmission control unit 180 detects that the current flowing through the power transmitting coil 112 has decreased to less than a certain value by, for example, comparing the detection result of the current value flowing through the power transmitting resonant circuit 110 by the current sensor 118 with a predetermined threshold, and determines that the power transmitting coil 112 and the power receiving coil 212 are in a non-opposing state. Instead of or in addition to the current sensor 118, it may also be determined that the power transmitting coil 112 and the power receiving coil 212 are in a non-opposing state by, for example, comparing the detection result of the current value flowing through the tertiary resonant circuit 310 by the current sensor 318 with a predetermined threshold.

[0029] When the power transmission control unit 180 determines that the power transmitting device 100 is in a non-opposed state, it switches the power transmitting device 100 to a standby state. More specifically, the power transmitting control unit 180 opens the power transmitting switching element 116 to reduce the capacitance of the power transmitting resonant capacitor 114, thereby switching the input impedance Z1 of the power transmitting resonant circuit 110 to a large value and switching the state to a state in which a small standby current flows through the power transmitting resonant circuit 110, and also shorts the tertiary resonance switching element 316 to switch the tertiary coil 312 and the tertiary resonant capacitor 314 to a non-resonant state. As a result, the power transmitting device 100 enters a standby state in which a standby current flows through the power transmitting coil 112, and power supply from the power transmitting coil 112 to the power receiving coil 212 is stopped. Note that the "standby state of the power transmitting device 100" refers to a state in which the power transmitting circuit 130 is driven but power is not supplied to the power receiving device 200. The power transmission control unit 180 may further control the on / off of the power transmission circuit 130, and switch on / off the power supply from the power source to the power transmission resonant circuit 110. For example, when a predetermined time has elapsed since the power transmission device 100 entered a standby state or when the power receiving device 200 is not detected, the power transmission control unit 180 can suppress power loss of the power transmission device 100 by turning off the power transmission circuit 130 and switching the power transmission device 100 to a stopped state.

[0030] In this embodiment, the power transmission control unit 180 first opens (turns off) the power transmission switching element 116, and then shorts (turns on) the tertiary resonance switching element 316. That is, the power transmission switching element 116 is switched when the current value I1 flowing through the power transmitting coil 112 decreases. This configuration makes it possible to suppress or prevent the occurrence of surge voltage. Note that, if the occurrence of surge voltage is not a problem, the shorting of the tertiary resonance switching element 316 and the opening of the power transmission switching element 116 may be performed simultaneously or in any order.

[0031] As described above, according to the power transmitting device 100 of this embodiment, the tertiary resonant circuit 310 includes the tertiary coil 312, the tertiary resonant capacitor 314, and the tertiary resonance switching element 316 connected in parallel with the tertiary coil 312. The tertiary resonance switching element 316 switches between a resonant state and a non-resonant state of the tertiary resonant circuit 310 by switching between an open state and a short-circuit state of the tertiary resonance switching element 316. When switching the power receiving device 200 to a standby state in which power is not supplied, the power transmitting control unit 180 shorts the tertiary resonance switching element 316 to switch the tertiary coil 312 and the tertiary resonant capacitor 314 to a non-resonant state. According to the power transmitting device 100 of this embodiment, the short-circuiting of the tertiary resonance switching element 316 can put the tertiary coil 312 and the tertiary resonant capacitor 314 into a non-resonant state. Therefore, for example, even if a short-circuit failure occurs in the tertiary resonance switching element 316, the tertiary resonant circuit 310 is fixed in a non-resonant state. Therefore, it is possible to suppress or prevent an increase in the number of components and size of the power transmitting device 100 without providing a protection circuit for preventing failure of each part of the power transmitting device 100 due to a short-circuit failure.

[0032] According to the power transmitting device 100 of this embodiment, when switching to a conducting state in which power is supplied to the power receiving device 200, the power transmitting control unit 180 opens the tertiary resonance switching element 316 to switch the tertiary coil 312 and the tertiary resonant capacitor 314 to a resonant state. Because the tertiary resonance switching element 316 is opened when power is supplied to the power receiving device 200, no current flows through the tertiary resonance switching element 316. This reduces or prevents power loss in the tertiary resonance switching element 316. Furthermore, since a large current is prevented from flowing through the tertiary resonance switching element 316 during power supply, the current capacity of the tertiary resonance switching element 316 can be reduced, thereby reducing or preventing an increase in the size of the power transmitting device 100. Furthermore, an increase in standby capacitance due to the parasitic capacitance of the tertiary resonance switching element 316 in a non-resonant state can be reduced, thereby preventing a resonance point from occurring on the power supply side. Therefore, the electromagnetic compatibility (EMC) of the power transmitting device 100 can be improved, and degradation in the performance of the power supply circuit 140 can be suppressed or prevented.

[0033] The power transmitting device 100 of this embodiment further includes a power transmission switching element 116 as a current switching unit that is controlled by the power transmission control unit 180 and switches the magnitude of the current flowing through the power transmitting resonant circuit 110. When switching from the energized state to the standby state, the power transmission control unit 180 further controls the power transmission switching element 116 to switch the current flowing through the power transmitting resonant circuit 110 to a current that is smaller than the current flowing through the power transmitting resonant circuit 110 in the energized state. When power is not supplied to the power receiving device 200, it is possible to suppress or prevent unnecessary power that does not contribute to power transmission from being supplied to the power transmitting resonant circuit 110.

[0034] According to the power transmitting device 100 of this embodiment, when transitioning from a conducting state to a standby state, the power transmitting control unit 180 controls the power transmitting switching element 116 to increase the current flowing through the power transmitting resonant circuit 110 to switch the power transmitting resonant circuit 110 to a resonant state, and then short-circuits the tertiary resonance switching element 316 to switch the tertiary coil 312 and the tertiary resonant capacitor 314 to a non-resonant state. This makes it possible to suppress or prevent a sudden increase in impedance and suppress or prevent a large surge voltage from occurring in the tertiary resonant circuit 310.

[0035] B. Second embodiment: As shown in Fig. 2, the power transmitting device 100b according to the second embodiment differs from the power transmitting device 100 of the first embodiment in that it includes a tertiary resonant circuit 310b, but the other configurations are similar. The power transmitting device 100 of the first embodiment shown in Fig. 1 illustrates an example in which the tertiary resonant circuit 310 is provided as a closed circuit independent of the power transmitting resonant circuit 110. In contrast, in the power transmitting device 100b of the present embodiment, the tertiary resonant circuit 310b is connected in series to the power transmitting coil 112 of the power transmitting resonant circuit 110.

[0036] The configuration of the tertiary resonant circuit 310b is the same as that of the tertiary resonant circuit 310 shown in the first embodiment, with the tertiary resonant capacitor 314 connected in parallel to the tertiary coil 312 and the tertiary resonance switching element 316 connected in parallel to the tertiary coil 312. The settings of the capacitance and the like of the power transmitting resonant capacitor 114 are the same as in the first embodiment, and are set so that the power transmitting resonant capacitor 114 and the power transmitting coil 112 resonate at an angular frequency of a predetermined operating frequency when the power transmitting switching element 116 is short-circuited. The capacitance of the tertiary resonant capacitor 314 is also set, as in the first embodiment, so that the tertiary resonant capacitor 314 and the tertiary coil 312 resonate at the angular frequency of a predetermined operating frequency.

[0037] According to the power transmitting device 100b of this embodiment, the tertiary resonant circuit 310b is connected in series with the power transmitting resonant circuit 110. In this configuration of the power transmitting device 100b as well, the tertiary coil 312 and the tertiary resonant capacitor 314 can be brought into a non-resonant state by short-circuiting the tertiary resonance switching element 316. Therefore, an increase in the number of components and size of the power transmitting device 100b can be suppressed or prevented without providing a protection circuit for preventing failures in each part of the power transmitting device 100b due to a short-circuit failure.

[0038] C. Third embodiment: 3, a power transmitting device 100c according to the third embodiment includes a power transmitting resonant circuit 110c, a current sensor 118, a power transmitting resonance switching element 126, a power transmitting circuit 130, a power supply circuit 140, a magnetic flux detection unit 170, and a power transmitting control unit 180. The power transmitting device 100c according to the third embodiment differs from the power transmitting device 100 according to the first embodiment in that it includes a power transmitting resonant circuit 110c instead of the power transmitting resonant circuit 110, does not include a tertiary resonant circuit 310, further includes a power transmitting resonance switching element 126, and includes a power transmitting switching element 116c instead of the power transmitting switching element 116, but otherwise has the same configuration.

[0039] The power transmitting resonant circuit 110c differs from the power transmitting resonant circuit 110 in that it includes a power transmitting resonant capacitor 114c instead of the power transmitting resonant capacitor 114. The power transmitting resonant capacitor 114c is a resonant capacitor for resonating the power supplied to the power transmitting coil 112. Unlike the power transmitting resonant capacitor 114, the power transmitting resonant capacitor 114c is not a variable capacitor but a capacitor having a predetermined capacitance. The power transmitting resonant circuit 110c is a parallel resonant circuit in which the power transmitting coil 112 and the power transmitting resonant capacitor 114c are connected in parallel, and is configured in a so-called PS system.

[0040] The power transmission switching element 116c switches on / off the power supply from the power transmission circuit 130 to the power transmission resonant circuit 110c under the control of the power transmission control unit 180. In this embodiment, the power transmission switching element 116c is a bidirectional switch provided between the power transmission circuit 130 and the power transmission resonant circuit 110c. As with the power transmission switching element 116, the power transmission switching element 116c may be a semiconductor element that controls current, such as an IGBT, a MOSFET, or an FET. The power transmission control unit 180 shorts (turns on) the power transmission switching element 116c to turn on the power supply from the power transmission circuit 130 to the power transmission resonant circuit 110c, and opens (turns off) the power transmission switching element 116c to turn off the power supply from the power transmission circuit 130 to the power transmission resonant circuit 110c.

[0041] 3, the power transmission switching element 116c is arranged only on the positive side between the power transmission circuit 130 and the power transmission resonant circuit 110c. However, the power transmission switching element 116c is not limited to this, and a bidirectional switch may be arranged separately on the positive side and the negative side. According to the power transmitting device 100c configured in this manner, by dividing the cutoff point of the power supply from the power transmission circuit 130 to the power transmission resonant circuit 110c into the positive side and the negative side, it is possible to suppress or prevent so-called common mode noise occurring on the positive side and the negative side.

[0042] The power transmitting resonance switching element 126 switches between a resonant state and a non-resonant state between the power transmitting coil 112 and the power transmitting resonance capacitor 114c by changing the impedance between the power transmitting coil 112 and the power transmitting resonance capacitor 114c. Like the power transmitting switching element 116c, the power transmitting resonance switching element 126 can employ a semiconductor element for controlling current, such as an IGBT, a MOSFET, or an FET. The power transmitting control unit 180 shorts (turns on) the power transmitting resonance switching element 126 to bring the power transmitting coil 112 and the power transmitting resonance capacitor 114c into a non-resonant state, and opens (turns off) the power transmitting resonance switching element 126 to bring the power transmitting coil 112 and the power transmitting resonance capacitor 114c into a resonant state in which they can resonate.

[0043] The power transmitting device 100c of this embodiment includes a power transmitting resonance switching element 126 connected in parallel to the power transmitting resonant circuit 110c, and a power transmitting control unit 180 that controls the power transmitting resonance switching element 126. The power transmitting resonance switching element 126 switches the power transmitting resonant circuit 110c between a resonant state and a non-resonant state by switching the impedance between the power transmitting coil 112 and the power transmitting resonant capacitor 114c. When switching the power transmitting device 100c from a conducting state to a standby state, the power transmitting control unit 180 short-circuits the power transmitting resonance switching element 126 to switch the power transmitting coil 112 and the power transmitting resonant capacitor 114c to a non-resonant state. According to the power transmitting device 100c of this embodiment, the power transmitting coil 112 and the power transmitting resonant capacitor 114c can be placed in a non-resonant state by short-circuiting the power transmitting resonance switching element 126. Therefore, for example, even if a short-circuit failure occurs in the power transmitting resonance switching element 126, the power transmitting resonant circuit 110c is fixed in a non-resonant state. Therefore, without providing a protection circuit for preventing failure of each part of the power transmitting device 100c due to a short-circuit failure, an increase in the number of parts and size of the power transmitting device 100c can be suppressed or prevented.

[0044] According to the power transmitting device 100c of this embodiment, when switching from a standby state to a conducting state, the power transmitting control unit 180 opens the power transmitting resonance switching element 126 to bring the power transmitting coil 112 and the power transmitting resonance capacitor 114c into a resonant state. When power is supplied to the power receiving device 200, the power transmitting resonance switching element 126 is opened, so no current flows through the power transmitting resonance switching element 126. This makes it possible to suppress or prevent power loss in the power transmitting resonance switching element 126. Furthermore, since it is possible to prevent a large current from flowing through the power transmitting resonance switching element 126 during power supply, it is possible to reduce the current capacity of the power transmitting resonance switching element 126, thereby suppressing or preventing an increase in the size and cost of the power transmitting device 100c. Furthermore, it is possible to suppress an increase in standby capacity due to the parasitic capacitance of the power transmitting resonance switching element 126 in a non-resonant state, and it is possible to suppress the occurrence of a resonance point on the power supply side. Therefore, the electromagnetic compatibility (EMC) of the power transmitting device 100c is improved, and the performance degradation of the power supply circuit 140 can be suppressed or prevented.

[0045] The power transmitting device 100c of this embodiment includes a power transmission switching element 116c that is controlled by the power transmission control unit 180 and switches on and off the power supply from the power source to the power transmitting resonant circuit 110c. When switching from the energized state to the standby state, the power transmission control unit 180 further opens the power transmission switching element 116c to stop the power supply from the power source to the power transmitting resonant circuit 110c. When power is not supplied to the power receiving device 200, it is possible to suppress or prevent unnecessary power that does not contribute to power transmission from being supplied to the power transmitting resonant circuit 110c.

[0046] D. Other Embodiments: (D1) In the above embodiments, examples have been shown in which the tertiary resonant circuit 310, the tertiary resonant circuit 310b, and the power transmitting resonant circuit 110c are configured in a primary-parallel-secondary-series configuration. However, the tertiary resonant circuit 310, the tertiary resonant circuit 310b, and the power transmitting resonant circuit 110c may employ various circuit configurations other than the primary-parallel-secondary-series configuration. For example, a primary-parallel-series-secondary-series configuration (also called a "PSS configuration") may be used, in which multiple resonant capacitors are further connected in series to the power transmitting coil.

[0047] (D2) In the first and second embodiments, an example was shown in which the power transmitting resonant capacitor 114 was a variable capacitor including two capacitors connected in parallel. However, the power transmitting resonant capacitor 114 may be a variable capacitor whose capacitance changes depending on an input control voltage or the like. In this case, the power transmitting switching element 116 outputs a control voltage.

[0048] (D3) In the above first and second embodiments, an example was shown in which the power transmission switching element 116 is provided to switch the magnitude of the current flowing through the power transmission resonant circuit 110. However, for example, when there is no need to flow a standby current through the power transmission resonant circuit 110, the power transmitting device may be configured not to include the power transmission switching element 116. Similarly, the power transmitting device 100c of the third embodiment may also be configured not to include the power transmission switching element 116c.

[0049] (D4) In the first embodiment, the power transmitting resonant capacitor 114 includes the first capacitor 114t, the power transmitting switching element 116 connected in series to the first capacitor 114t, and the second capacitor 114s connected in parallel to the first capacitor 114t and the power transmitting switching element 116. However, for example, the second capacitor 114s may be omitted. That is, the power transmitting resonant circuit 110 may include the power transmitting resonant capacitor 114 including the first capacitor 114t and the power transmitting switching element 116 connected in series to the first capacitor 114t. In this case, the capacitance of the power transmitting resonant capacitor 114 becomes the capacitance of the first capacitor 114t when the power transmitting switching element 116 is short-circuited. When the power transmitting switching element 116 is open-circuited, the output capacitance of the power transmitting switching element 116 determines the standby current. With this configuration, the standby current flowing through the power transmitting resonant circuit 110 can be further reduced.

[0050] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with one or more hardware-programmed processors and memories in combination with a processor configured with one or more hardware memories. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0051] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0052] 100, 100b, 100c... power transmitting device, 110, 110c... power transmitting resonant circuit, 112... power transmitting coil, 114, 114c... power transmitting resonant capacitor, 126... power transmitting resonance switching element, 180... power transmitting control unit, 200... power receiving device, 212... power receiving coil, 310, 310b... tertiary resonant circuit, 312... tertiary coil, 314... tertiary resonant capacitor, 316... tertiary resonance switching element

Claims

1. A power transmission device (100, 100b) that supplies power to a power reception device (200) having a power reception coil (212) in a wireless manner, a power transmitting resonant circuit (110) including a power transmitting coil (112) magnetically coupled to the power receiving coil and a power transmitting resonant capacitor (114) connected in series to the power transmitting coil; A third-order resonant circuit (310, 310b), a tertiary coil (312) magnetically coupled to the transmitting coil and the receiving coil; a tertiary resonant capacitor (314) connected in parallel with the tertiary coil; a tertiary resonant circuit including a tertiary resonance switching element (316) connected in parallel with the tertiary coil, the tertiary resonance switching element switching between an open state and a non-resonant state of the tertiary resonant circuit by switching between an open state and a short-circuit state of the tertiary resonance switching element; a power transmission control unit (180) that controls the tertiary resonance switching element, When switching from a power-on state in which power is supplied to the power receiving device to a standby state in which power is not supplied to the power receiving device, the power transmission control unit short-circuits the tertiary resonance switching element to switch the tertiary coil and the tertiary resonance capacitor to a non-resonant state. Power transmission equipment.

2. The power transmitting device according to claim 1 , When switching from the standby state to the energized state, the power transmission control unit opens the tertiary resonance switching element to switch the tertiary coil and the tertiary resonance capacitor to a resonant state. Power transmission equipment.

3. The power transmitting device according to claim 1 , Further, a current switching unit (116) is provided which is controlled by the power transmission control unit and switches the magnitude of the current flowing through the power transmission resonant circuit, When switching from the energized state to the standby state, the power transmission control unit further controls the current switching unit to switch the current flowing through the power transmission resonant circuit to a current smaller than the current flowing through the power transmission resonant circuit in the energized state. Power transmission equipment.

4. The power transmitting device according to claim 3, When the power transmission control unit transitions from the energized state to the standby state, After controlling the current switching unit to switch the current flowing through the power transmitting resonant circuit to a current smaller than the current flowing through the power transmitting resonant circuit in the energized state, The tertiary resonance switching element is short-circuited to switch the tertiary coil and the tertiary resonance capacitor to a non-resonant state. Power transmission equipment.

5. The power transmitting device according to any one of claims 1 to 4, the tertiary resonant circuit is connected in series with the power transmitting resonant circuit; Power transmission equipment.

6. A power transmission device (100c) that supplies power to a power reception device (200) having a power reception coil (212) in a contactless manner, a power transmitting resonant circuit (110c) including a power transmitting coil (112) magnetically coupled to the power receiving coil and a power transmitting resonant capacitor (114c) connected in parallel to the power transmitting coil; a power transmission resonance switching element (126) connected in parallel to the power transmission resonance circuit and configured to switch between a resonant state and a non-resonant state of the power transmission resonance circuit by switching the impedance between the power transmission coil and the power transmission resonance capacitor; a power transmission control unit (180) that controls the power transmission resonance switching element, the power transmission control unit short-circuits the power transmission resonance switching element to switch the power transmission coil and the power transmission resonance capacitor to a non-resonant state when switching from a power-on state in which power is supplied to the power receiving device to a standby state in which power is not supplied to the power receiving device. Power transmission equipment.

7. The power transmitting device according to claim 6, When switching from the standby state to the energized state, the power transmission control unit opens the power transmission resonance switching element to bring the power transmission coil and the power transmission resonance capacitor into a resonant state. Power transmission equipment.

8. The power transmitting device according to claim 6, Further, a power transmission switching element (116c) is provided which is controlled by the power transmission control unit and switches on / off the power supply from a power source to the power transmission resonant circuit, When switching from the energized state to the standby state, the power transmission control unit further opens the power transmission switching element to stop the power supply from the power source to the power transmission resonant circuit. Power transmission equipment.

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