Power receiving device

Abstract

To solve a problem of increased cost and size of a circuit for raising temperature of a battery.SOLUTION: A power receiving device 100 that receives first AC power in a non-contact manner includes: a first resonance circuit 110; a power conversion circuit 120; a battery 130; a second resonance circuit 140 connected to an AC power input unit 141 in the power conversion circuit; a battery sensor 160; a power receiving sensor 180; and a control circuit 150. The power conversion circuit can convert first AC power AC1 supplied from the first resonance circuit 110 into first DC power and supply it to the battery, and can convert second DC power supplied from the battery into second AC power and supply it to the second resonance circuit. The control circuit performs conversion of the second DC power and supply to the second resonance circuit when temperature detected by the battery sensor is included in a predetermined first range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power receiving device.

Background Art

[0002] A battery may have a temperature suitable for use. For example, a lithium-ion battery is preferably used at about 20 degrees Celsius. A lithium-ion battery is likely to deteriorate when used in a low-temperature state of about 0 degrees Celsius or lower. Therefore, there is a technique for raising the temperature of the battery to a temperature suitable for use. In Patent Document 1, an AC power supply is connected to a battery as a load of a non-contact power supply system. The AC power supply in Patent Document 1 raises the temperature of the battery by energizing the battery. Note that in Patent Document 1, a specific application example of the AC power supply connected to the battery of the non-contact power supply system is not shown.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when adding an AC power supply, there has been a problem that the cost and size of the circuit for raising the temperature of the battery increase.

Means for Solving the Problems

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

[0006] According to a first aspect of the present disclosure, there is provided a power receiving device (100) that non - contactingly receives first alternating current power (AC1) by a magnetic field. The power receiving device includes a first resonance circuit (110) including a power receiving coil (111) that receives the first alternating current power, the first resonance circuit having a first resonance frequency, a power conversion circuit (120) that bidirectionally converts alternating current power and direct current power, a battery (130) that is charged with first direct current power (DC1) supplied via the power conversion circuit, a second resonance circuit (140) connected to an input portion of the alternating current power in the power conversion circuit, the second resonance circuit having a second resonance frequency different from the first resonance frequency, a battery sensor (160) that measures the temperature of the battery, a power receiving sensor (180) that detects reception of the first alternating current power, and a control circuit (150) that controls the power receiving device. The power conversion circuit can convert the first alternating current power supplied from the first resonance circuit into the first direct current power and supply it to the battery by controlling the power conversion circuit according to the first resonance frequency, and can convert second direct current power (DC1) supplied from the battery into second alternating current power (AC2) and supply it to the second resonance circuit by controlling the power conversion circuit according to the second resonance frequency. The control circuit performs the conversion of the second direct current power and the supply to the second resonance circuit when the first alternating current power is not being received by the power receiving sensor and the temperature detected by the battery sensor is included in a predetermined first range, and does not perform the conversion of the second direct current power and the supply to the second resonance circuit when the first alternating current power is not being received by the power receiving sensor and the temperature detected by the battery sensor is included in a second range higher than the first range.

[0007] In such a configuration, when the battery is not receiving the first AC power and the temperature of the battery is within the first range, the power conversion circuit performs power conversion between the battery and the second resonance circuit. When the battery is energized, the battery is heated up. That is, the power receiving device of the present disclosure can control the temperature rise of the battery by the power conversion circuit. For example, when the second resonance circuit is composed of only a reactor and a capacitor, the power receiving device of the present disclosure is configured more simply than the form using an AC power source for the temperature rise of the battery. Further, the power receiving device of the present disclosure does not radiate a magnetic field from the power receiving coil by heating up at a second resonance frequency different from the first resonance frequency of the first resonance circuit that receives power. Therefore, the power receiving device of the present disclosure can prevent an increase in cost and size for the circuit that heats up the battery.

[0008] According to a second aspect of the present disclosure, there is provided a power receiving device (100x) that receives AC power non - contactlessly by a magnetic field. The power receiving device includes a resonance circuit (110) including a power receiving coil (111) that receives the AC power, a power conversion circuit (120x) that converts the AC power into DC power, a battery (130) that charges the DC power, a smoothing capacitor (170) connected in parallel between the power conversion circuit and the battery, and a switch (Swx) connected in series to the smoothing capacitor, a battery sensor (160) that measures the temperature of the battery, and a control circuit (150x) that controls the power receiving device. When the control circuit detects, by the battery sensor, a first temperature included in a first range predetermined for the temperature, the control circuit performs control to turn off the switch. When the control circuit detects, by the battery sensor, a second temperature included in a second range higher than the first range, the control circuit controls the switch to be in an on state.

[0009] By adopting such a configuration, the power receiving device of the present disclosure smooths the current supplied to the battery by the smoothing capacitor when the switch is in the on state. The power receiving device of the present disclosure does not smooth the current supplied to the battery when the switch is in the off state. That is, when the switch is in the off state, a current including a frequency component of the AC power is supplied to the battery. When a current including a frequency component is supplied to the battery, the battery heats up more than when a current not including a frequency component is supplied. Therefore, the power receiving device of the present disclosure is configured more simply than the form using an AC power source for heating the battery by adding only a switch to the smoothing capacitor. That is, the power receiving device of the present disclosure can prevent an increase in cost and size for the circuit that heats up the battery.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0011] A. First Embodiment: A-1. Configuration of the Device: The non-contact power supply system 10 shown in FIG. 1 supplies power to the battery 130 non-contact by a magnetic field. The non-contact power supply system 10 includes a power transmission device 200 and a power reception device 100. The non-contact power supply system 10 supplies power to the power reception device 100 non-contact from the power transmission device 200. The non-contact power supply system 10 supplies power non-contact to, for example, the battery 130 mounted on a vehicle.

[0012] The power transmission device 200 supplies AC power to the power reception device 100 non-contact by a magnetic field. The power transmission device 200 includes an AC power supply device 210 and a power transmission resonance circuit 220.

[0013] The AC power supply device 210 supplies AC power of a predetermined operating frequency to the power transmission resonance circuit 220. The AC power supply device 210 includes a power supply circuit and a power transmission circuit. The power supply circuit is, for example, an AC / DC converter circuit that converts the AC power supplied from the utility power supply into DC power. The power transmission circuit is an inverter that converts the DC power supplied from the power supply circuit into AC power of the operating frequency. The operating frequency is, for example, 85 kHz and is set using a predetermined power transmission frequency defined by the Radio Law or the like. Note that the operating frequency is also a frequency corresponding to the resonance frequency of the power transmission resonance circuit 220 described later.

[0014] The power transmission resonance circuit 220 magnetically couples with the power reception coil 111 in a resonant state. The power transmission resonance circuit 220 includes a power transmission coil 222 and a power transmission resonance capacitor 221 connected in series to the power transmission coil 222.

[0015] The power transmission resonance capacitor 221 resonates the power transmission resonance circuit 220 with the AC power of the operating frequency in a state where the power transmission coil 222 and the power reception coil 111 are magnetically coupled. That is, the capacitance of the power transmission resonance capacitor 221 is set so that the operating frequency of the AC power supply device 210 and the resonance frequency of the power transmission resonance circuit 220 substantially coincide in a state where the power transmission coil 222 and the power reception coil 111 are magnetically coupled.

[0016] The power transmission coil 222 generates a magnetic field corresponding to the operating frequency of the AC power supply device 210. Further, the power transmission coil 222 magnetically couples with the power reception coil 111 to transmit AC power to the power reception coil 111. That is, the power transmission coil 222 performs non-contact power transmission by utilizing the electromagnetic induction phenomenon.

[0017] The power reception device 100 receives AC power from the power transmission device 200 in a non-contact manner by means of a magnetic field. The AC power received by the power reception coil 111 included in the power reception resonance circuit 110 is referred to as the first AC power AC1. The power reception device 100 includes a power reception resonance circuit 110, a power conversion circuit 120, a battery 130, a temperature rise circuit 140, a battery sensor 160, a control circuit 150, a smoothing capacitor 170, and a power reception sensor 180.

[0018] The power reception resonance circuit 110 includes a power reception coil 111 and a power reception resonance capacitor 112 connected in series to the power reception coil 111. The power reception resonance circuit 110 has a first resonance frequency. In this specification, the power reception resonance circuit 110 is also referred to as the first resonance circuit 110.

[0019] The power reception coil 111 magnetically couples with the power transmission coil 222 by receiving the magnetic field emitted by the power transmission coil 222. The power reception coil 111 is used in a state of facing the power transmission coil 222 to receive the magnetic field emitted by the power transmission coil 222. Thereby, the power reception coil 111 receives the first AC power AC1 in a non-contact manner.

[0020] The power reception resonance capacitor 112 resonates the power reception resonance circuit 110 with the first AC power AC1 in a state where the power reception coil 111 and the power transmission coil 222 are magnetically coupled. That is, the capacitance of the power reception resonance capacitor 112 is set such that the frequency of the first AC power AC1 and the first resonance frequency of the power reception resonance circuit 110 substantially coincide in a state where the power transmission coil 222 and the power reception coil 111 are magnetically coupled.

[0021] In this embodiment, the power reception resonance capacitor 112 includes a positive-side first capacitor 112P and a negative-side second capacitor 112N. By arranging resonance capacitors on both the positive and negative sides, common-mode noise can be suppressed.

[0022] The temperature-raising circuit 140 is used to raise the temperature of the battery 130. The function of the temperature-raising circuit 140 will be described in detail later. The temperature-raising circuit 140 is composed of a series connection of a reactor 141 and a capacitor 142. The temperature-raising circuit 140 has a second resonance frequency higher than the first resonance frequency of the power reception resonance circuit 110. For example, the second resonance frequency is five times the frequency of the first resonance frequency. That is, the temperature-raising circuit 140 has a second resonance frequency different from the first resonance frequency of the power reception resonance circuit 110. In this specification, the temperature-raising circuit 140 is also referred to as the second resonance circuit 140.

[0023] The temperature-raising circuit 140 is connected in parallel between the power reception resonance circuit 110 and the power conversion circuit 120. That is, the temperature-raising circuit 140 is connected to the output part of the power reception resonance circuit 110 and the input part of the AC power in the power conversion circuit 120.

[0024] The power conversion circuit 120 bidirectionally converts AC power and DC power. More specifically, the power conversion circuit 120 is a full-bridge circuit that uses four MOSFETs (metal-oxide-semiconductor field-effect transistors) as switching elements. The power conversion circuit 120 includes two leg circuits, a first leg circuit 121 and a second leg circuit 122. The switch Sw is driven by receiving a voltage corresponding to the command of the control circuit 150 at its gate. In this specification, the power conversion circuit 120 is also referred to as the synchronous rectification circuit 120.

[0025] In the leg circuit, two switches Sw are connected in series. Further, the leg circuit connects the positive line Lp and the negative line Ln of the DC power. One of the output terminals of the temperature rising circuit 140 is connected between the two switches Sw of the leg circuit. That is, the position between the two switches Sw of the leg circuit is the position of the input terminal in the power conversion circuit 120. Regarding the input terminal of the power conversion circuit 120, the leg circuit having the terminal P1 is the first leg circuit 121. The leg circuit having the terminal P2 is the second leg circuit 122.

[0026] As described above, the power conversion circuit 120 converts AC power and DC power bidirectionally. The conversion by the power conversion circuit 120 will be described in detail later.

[0027] The smoothing capacitor 170 is connected in parallel between the output of the power conversion circuit 120 and the battery 130. The smoothing capacitor 170 smoothes the DC current and DC voltage supplied to the battery 130.

[0028] The power receiving sensor 180 detects the reception of the first AC power AC1. The power receiving sensor 180 detects the reception of the first AC power AC1 by detecting the current in the output part of the power conversion circuit 120. More specifically, the power receiving sensor 180 detects the current flowing through the battery 130 between the output part of the power conversion circuit 120 and the battery 130. That is, the power receiving sensor 180 is a current sensor that measures the current value of the DC power.

[0029] The battery 130 is charged by the first DC power DC1 supplied through the power conversion circuit 120. Further, the battery 130 outputs the stored power as the second DC power DC2. The function of the battery 130 will be described in detail later.

[0030] The battery 130 is, for example, a lithium-ion battery. Lithium-ion batteries are prone to deterioration when used in a low-temperature state of about 0 degrees Celsius or lower. Lithium-ion batteries are preferably used at around 20 degrees Celsius. The temperature increase of the battery 130 by the temperature increase circuit 140 is to increase the temperature to a temperature suitable for the use of the battery 130.

[0031] The battery sensor 160 measures the temperature of the battery 130. For example, when the battery 130 is a lithium-ion battery, the battery sensor 160 measures the temperature of the cells of the lithium-ion battery. The battery sensor 160 is connected to the control circuit 150. The temperature acquired by the battery sensor 160 is output to the control circuit 150.

[0032] The control circuit 150 controls the power receiving device 100. The control circuit 150 includes a control unit 151 and a drive circuit 152.

[0033] The drive circuit 152 drives the switch Sw. More specifically, the drive circuit 152 outputs the power required for driving the switch Sw in response to a command from the control unit 151. The drive circuit 152 is connected to the gates of all the switches Sw of the power conversion circuit 120. That is, the drive circuit 152 drives the switch Sw by applying a gate voltage required for the on and off operations of the switch Sw to the gate of the switch Sw. In FIG. 1, for ease of understanding of the technology, the connection between the drive circuit 152 and the gate is omitted.

[0034] The control unit 151 generates a signal for controlling the on and off operations of the switch Sw. The control unit 151 is mainly composed of, for example, a microcomputer and includes a CPU, a ROM, a RAM, etc. (not shown). The control unit 151 is connected to the battery sensor 160. The control by the control unit 151 will be described in detail later.

[0035] A-2. Charging and Temperature Increase of the Battery by the Power Receiving Device: Using FIGS. 2 and 3, a method for charging the battery 130 in the power receiving device 100 will be described. For ease of understanding of the technology, in FIGS. 2 and 3, the illustration of the power transmitting device 200 is omitted. The power receiving device 100 receives the first AC power AC1 by the power receiving coil 111. The arrow AC1 in FIG. 2 indicates the direction in which the first AC power AC1 is supplied.

[0036] The power conversion circuit 120 performs rectification according to the first resonance frequency. The arrow Ic in FIG. 2 represents the flow of the positive current in one cycle of the first AC power AC1. The arrow Ic in FIG. 3 represents the flow of the negative current in one cycle of the first AC power AC1. That is, the power conversion circuit 120 rectifies the current of the first AC power AC1 at the first resonance frequency through the switch Sw in each of the two leg circuits. As a result, the first AC power AC1 is converted into the first DC power DC1. The arrow DC1 in FIG. 2 indicates the direction in which the first DC power DC1 is supplied. The battery 130 is charged with the first DC power DC1.

[0037] That is, the power conversion circuit 120 can convert the first AC power AC1 supplied from the first resonance circuit 110 into the first DC power DC1 and supply it to the battery 130 by controlling the power conversion circuit 120 according to the first resonance frequency.

[0038] Using FIGS. 4 and 5, a method for heating the battery 130 in the power receiving device 100 will be described. Similar to FIGS. 2 and 3, in FIGS. 4 and 5, the illustration of the power transmitting device 200 is omitted. Note that the heating of the battery 130 is performed in a state where the reception of the first AC power AC1 is not being performed. The battery 130 outputs the stored power as the second DC power DC2. The arrow DC2 in FIGS. 4 and 5 indicates the direction in which the second DC power DC2 is supplied.

[0039] The power conversion circuit 120 performs power conversion according to the second resonance frequency. The temperature-rising current Ir indicated by the arrow in FIG. 4 is the flow of the current output from the battery 130, and represents the flow when it becomes the positive current of the second AC power AC2. The temperature-rising current Ir indicated by the arrow in FIG. 5 is the flow of the current output from the battery 130, and represents the flow when it becomes the negative current of the second AC power AC2. The temperature-rising circuit 140 resonates at the second resonance frequency. Therefore, the power conversion circuit 120 operates the switch Sw at a driving frequency according to the second resonance frequency. That is, the power conversion circuit 120 converts the second DC power DC2 into the second AC power AC2 according to the second resonance frequency through the switch Sw driven at the driving frequency according to the second resonance frequency. Thus, the second AC power AC2 is supplied to the temperature-rising circuit 140. Since the second AC power AC2 according to the second resonance frequency is not supplied to the power receiving resonance circuit 110 having the first resonance frequency, no magnetic field is radiated from the power receiving coil 111.

[0040] Note that since the temperature-rising circuit 140 does not include a resistive element, it does not consume power. Therefore, during one cycle of the second AC power AC2, the second AC power AC2 supplied to the temperature-rising circuit 140 returns to the battery 130. The current flowing back to the battery 130 flows in the opposite direction to the direction of the temperature-rising current Ir.

[0041] That is, the power conversion circuit 120 can convert the second DC power DC2 supplied from the battery 130 into the second AC power AC2 and supply it to the temperature-rising circuit 140 by controlling the power conversion circuit 120 according to the second resonance frequency.

[0042] A-3. Control Method of Power Receiving Device: Using FIG. 6, the control method of the power receiving device 100 will be described. The control circuit 150 detects the reception of the first AC power AC1 by the power receiving sensor 180. Further, the control circuit 150 acquires the temperature of the battery 130 by the battery sensor 160. The control circuit 150 starts processing on the condition that the reception of the first AC power AC1 is not being performed, for example, triggered by the acquisition of the temperature of the battery 130.

[0043] In step S100 of FIG. 6, the control circuit 150 determines whether it is necessary to raise the temperature of the battery 130. More specifically, when the temperature detected by the battery sensor 160 is included in a predetermined first range, the control circuit 150 proceeds with the process to step S200. When the temperature detected by the battery sensor 160 is included in a second range higher than the first range, the control circuit 150 ends the process. That the second range is higher than the first range means that the lower limit of the second range is greater than the upper limit of the first range. For example, in the case of a lithium-ion battery, the temperature of the first range is a range of temperatures lower than 0 degrees Celsius. The second range is a range of 0 degrees Celsius or higher.

[0044] In step S200 of FIG. 6, the control circuit 150 performs or continues to raise the temperature of the battery 130. Specifically, the control circuit 150 converts the second DC power DC2 and supplies it to the temperature-raising circuit 140. That is, the control circuit 150 controls the power conversion circuit 120 according to the second resonance frequency, and as shown in FIGS. 4 and 5, converts the second DC power DC2 into the second AC power AC2 and supplies it to the temperature-raising circuit 140. When current is passed through the battery 130, the temperature of the battery 130 is raised. When the control circuit 150 has already performed the temperature raising, it continues the temperature raising. After raising the temperature of the battery 130, the control circuit 150 returns the process to step S100. The control circuit 150 raises the temperature of the battery 130 to a temperature suitable for use of the battery 130 by determining whether it is necessary to raise the temperature at the temperature of the heated battery 130.

[0045] In such a configuration, when the temperature of the battery 130 is within the first range in a state where the first AC power AC1 is not being received, the power conversion circuit 120 performs power conversion between the battery 130 and the second resonance circuit 140. When the battery 130 is energized, the battery 130 is heated up. That is, the power receiving device 100 of the present disclosure can control the temperature rise of the battery 130 by the power conversion circuit 120. For example, when the second resonance circuit 140 is composed only of the reactor 141 and the capacitor 142, the power receiving device 100 of the present disclosure is configured more simply than a form that uses an AC power supply for the temperature rise of the battery 130. Further, the power receiving device 100 of the present disclosure does not radiate a magnetic field from the power receiving coil 111 by performing temperature rise at a second resonance frequency different from the first resonance frequency of the first resonance circuit 110 that performs power reception. Therefore, the power receiving device 100 of the present disclosure can prevent an increase in cost and size for the circuit that raises the temperature of the battery 130.

[0046] Furthermore, since the second resonance frequency is higher than the first resonance frequency, when the power receiving device 100 of the present disclosure raises the temperature of a battery 130 that is less likely to deteriorate in the case of a high-frequency current, such as a lithium-ion battery, for example, it can raise the temperature at a frequency more suitable for the battery 130. Further, the higher the frequency of the power receiving device 100 of the present disclosure, the smaller the passive elements such as the reactor 141 and the capacitor 142 that constitute the circuit can be.

[0047] B. Second Embodiment: In the non-contact power supply system 10x of the second embodiment, the power receiving device 100x further includes a switch Swx connected in series to the smoothing capacitor 170. The switch Swx is, for example, a semiconductor relay. The control circuit 150x of the second embodiment controls the switch Swx connected in series to the smoothing capacitor 170. However, the power receiving device 100x of the second embodiment does not include the temperature rising circuit 140 and the power receiving sensor 180. In addition, in the power conversion circuit 120x of the second embodiment, the switch Sw in the power conversion circuit 120 of the first embodiment is replaced with a rectifying diode. That is, the power conversion circuit 120x converts AC power into DC power, but does not convert AC power and DC power bidirectionally. Other configurations of the non-contact power supply system 10x of the second embodiment are the same as those of the non-contact power supply system 10 of the first embodiment. For configurations of the non-contact power supply system 10x of the second embodiment that are different from those of the non-contact power supply system 10 of the first embodiment, an "x" is added to the end of the reference numeral.

[0048] The processing of the control circuit 150x will be described. The control circuit 150x starts processing, for example, triggered by obtaining the temperature of the battery 130. When the control circuit 150x detects, by the battery sensor 160, a first temperature included in a first range predetermined for the temperature of the battery 130, the control circuit 150x performs control to turn off the switch Swx. Specifically, the control circuit 150x does not perform smoothing of the DC power by the smoothing capacitor 170. As a result, a current called a ripple current or a pulsating current flows through the battery 130. That is, a current including a frequency component of the AC power is supplied to the battery 130. The control circuit 150x raises the temperature of the battery 130 until the battery 130 is heated to a temperature suitable for use of the battery 130.

[0049] When the battery sensor 160 detects a second temperature included in a second range higher than the first range, the control circuit 150x controls the switch Swx to be in the on state. That is, the control circuit 150x smoothes the DC power output from the power conversion circuit 120x by the smoothing capacitor 170. As a result, a more stable DC current is supplied to the battery 130 than when the DC power is not smoothed by the smoothing capacitor 170. Note that the first range and the second range are the same ranges as in the first embodiment.

[0050] With such a configuration, the power receiving device 100x of the present disclosure smoothes the current supplied to the battery 130 by the smoothing capacitor 170 in the on state of the switch Swx. The power receiving device 100x of the present disclosure does not smooth the current supplied to the battery 130 in the off state of the switch Sw. That is, in the off state of the switch Swx, a current including a frequency component of the AC power is supplied to the battery 130. When a current including a frequency component is supplied to the battery 130, the temperature of the battery 130 rises more than when a current not including a frequency component is supplied. Therefore, the power receiving device 100x of the present disclosure is configured more simply than a form in which an AC power source is used to increase the temperature of the battery 130 by adding only the switch Swx to the smoothing capacitor 170. That is, the power receiving device 100x of the present disclosure can prevent an increase in cost and size for a circuit that increases the temperature of the battery 130.

[0051] Furthermore, since it is not necessary to smooth the current used to increase the temperature of the battery 130, the power receiving device 100x of the present disclosure is more easily designed than a form in which the current used to increase the temperature of the battery 130 is smoothed.

[0052] C. Modification Example 1: In the first embodiment, the power receiving device 100 may further include a current sensor at the input of the power conversion circuit 120. The control circuit 150 controls the power conversion circuit 120 based on the detection value of the current sensor such that the heating current Ir based on the second resonance frequency becomes a predetermined reference current. The predetermined reference current is, for example, a current value based on the rated current of the battery 130. Note that the current sensor may be the power reception sensor 180 at the output of the power conversion circuit 120 in the first embodiment.

[0053] More specifically, the control circuit 150 adjusts the heating current Ir to be the reference current by the following method.

[0054] The control circuit 150 may adjust the heating current Ir by providing a period in which the battery 130 and the heating circuit 140 are disconnected by turning off the switch Sw of the power conversion circuit 120 in one cycle of the second AC power AC2. That is, the control circuit 150 can adjust the heating current Ir by adjusting the ratio between the period in which the battery 130 and the heating circuit 140 are disconnected and the period in which the battery 130 and the heating circuit 140 are connected in one cycle of the second AC power AC2.

[0055] With such a configuration, the power receiving device 100 of the present disclosure can control the temperature rise of the battery 130 without adding a circuit for adjusting the heating current Ir.

[0056] D. Modification Example 2: In the second embodiment, all of the rectifying elements of the power conversion circuit 120x are configured by rectifying diodes. However, the power conversion circuit 120x only needs to be able to convert AC power into DC power. That is, in the power conversion circuit 120x, some of the rectifying elements may be switches, or as in the first embodiment, all of the rectifying elements may be configured by switches.

[0057] E. Modification Example 3: (1) In the above embodiment, the power receiving resonant circuit 110 includes a power receiving resonant capacitor 112 as a resonant capacitor connected in series with the power receiving coil 111. However, the power receiving resonant circuit 110 may include a resonant capacitor connected in parallel with the power receiving coil 111. That is, the power receiving resonant circuit 110 may be a parallel resonant circuit. (2) In the above embodiment, the temperature rising circuit 140 has a second resonant frequency higher than the first resonant frequency. However, the temperature rising circuit 140 may have a second resonant frequency lower than the first resonant frequency. For example, the second resonant frequency is a frequency 1 / 5 higher than the first resonant frequency. (3) In the above embodiment, the switch Sw of the power conversion circuit 120 is a MOSFET. However, the switch Sw of the power conversion circuit 120 may be other switching elements. The switch Sw may be, for example, a BJT (Bipolar junction transistor) or an IGBT (Insulated Gate Bipolar Transistor). (4) In the above embodiment, the power receiving sensor 180 is a current sensor that measures the current value of direct current power. The power receiving sensor 180 may be other sensors. For example, the power receiving sensor 180 may be a voltage sensor that measures the voltage of direct current power. Further, the power receiving sensor 180 may be composed of a plurality of sensors. For example, the power receiving sensor 180 may be composed of a sensor that detects power reception by alternating current power and a sensor that detects power consumption of the battery 130 by direct current power. (5) In the above embodiment, the battery 130 is, by way of example, a lithium ion battery. However, the battery 130 may be other batteries 130. The battery 130 may be a lead battery, a nickel metal hydride battery, or the like. (6) In the first embodiment, the power conversion circuit 120 drives the switch Sw according to the first resonance frequency in order to rectify the first AC power AC1. However, the power conversion circuit 120 does not necessarily drive the switch Sw according to the first resonance frequency in order to rectify the first AC power AC1. When the switch Sw of the power conversion circuit 120 is provided with a parallel diode, the first AC power AC1 may be rectified only by the parallel diode.

[0058] The present disclosure is not limited to the above-described embodiments and modifications, and can be realized in various configurations without departing from the gist thereof. For example, the embodiments and modifications corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0059] F. Other Forms: The features of the present disclosure are shown as follows. (Form 1) A power receiving device (100) that receives the first AC power (AC1) non - contactly by a magnetic field, A first resonance circuit (110) including a power receiving coil (111) that receives the first AC power, the first resonance circuit having a first resonance frequency, A power conversion circuit (120) that bidirectionally converts AC power and DC power, A battery (130) that is charged with the first DC power (DC1) supplied via the power conversion circuit, A second resonance circuit (140) connected to the input part of the AC power in the power conversion circuit, the second resonance circuit having a second resonance frequency different from the first resonance frequency, A battery sensor (160) that measures the temperature of the battery, A power receiving sensor (180) that detects the reception of the first AC power, A control circuit (150) that controls the power receiving device, and is provided with The power conversion circuit can convert the first AC power supplied from the first resonance circuit into the first DC power and supply the first DC power to the battery by controlling the power conversion circuit according to the first resonance frequency, and can convert the second DC power (DC1) supplied from the battery into the second AC power (AC2) and supply the second AC power to the second resonance circuit by controlling the power conversion circuit according to the second resonance frequency. The control circuit When the first AC power is not received by the power receiving sensor and the temperature detected by the battery sensor is included in a predetermined first range, the conversion of the second DC power and the supply of the second DC power to the second resonance circuit are performed. A power receiving device that does not perform the conversion of the second DC power and the supply of the second DC power to the second resonance circuit when the first AC power is not received by the power receiving sensor and the temperature detected by the battery sensor is included in a second range higher than the first range. (Embodiment 2) A power receiving device according to Embodiment 1, wherein the second resonance frequency is higher than the first resonance frequency. (Embodiment 3) A power receiving device according to Embodiment 1, further comprising a current sensor provided at the input section or the output section of the power conversion circuit, wherein the control circuit controls the power conversion circuit based on the detection value of the current sensor such that the temperature-rising current based on the second resonance frequency becomes a predetermined reference current. (Embodiment 4) A power receiving device (100x) that receives AC power non-contactlessly by a magnetic field, a resonance circuit (110) including a power receiving coil (111) that receives the AC power, a power conversion circuit (120x) that converts the AC power into DC power, a battery (130) that charges the DC power, a smoothing capacitor (170) connected in parallel between the power conversion circuit and the battery A switch (Swx) connected in series with the smoothing capacitor, A battery sensor (160) for measuring the temperature of the battery, A control circuit (150x) for controlling the power receiving device, and The control circuit, When the battery sensor detects a first temperature included in a first range predetermined for the temperature, performs control to turn off the switch, A power receiving device that controls the switch to be in an on state when the battery sensor detects a second temperature included in a second range higher than the first range.

Explanation of Reference Numerals

[0060] 10, 10x... Non-contact power supply system, 100, 100x... Power receiving device, 110... First resonance circuit, 111... Power receiving coil, 120, 120x... Power conversion circuit, 130, 130x... Battery, 140... Second resonance circuit, 150, 150x... Control circuit, 160... Battery sensor, 170... Smoothing capacitor, 180... Power receiving sensor, AC1... First AC power, AC2... Second AC power, DC1... First DC power, DC2... Second DC power, Swx... Switch

Claims

1. A power receiving device (100) that receives first AC power (AC1) non - contactlessly by a magnetic field, a first resonance circuit (110) including a power receiving coil (111) that receives the first AC power, the first resonance circuit having a first resonance frequency; a power conversion circuit (120) that bidirectionally converts AC power and DC power; a battery (130) charged with first DC power (DC1) supplied via the power conversion circuit; a second resonance circuit (140) connected to an input portion of AC power in the power conversion circuit, the second resonance circuit having a second resonance frequency different from the first resonance frequency; a battery sensor (160) that measures the temperature of the battery; a power receiving sensor (180) that detects reception of the first AC power; and a control circuit (150) that controls the power receiving device, wherein the power conversion circuit can convert the first AC power supplied from the first resonance circuit into the first DC power and supply it to the battery by control of the power conversion circuit according to the first resonance frequency, and can convert second DC power (DC1) supplied from the battery into second AC power (AC2) and supply it to the second resonance circuit by control of the power conversion circuit according to the second resonance frequency, the control circuit, when the first AC power is not being received by the power receiving sensor and the temperature detected by the battery sensor is within a predetermined first range, performs the conversion of the second DC power and the supply to the second resonance circuit, and when the first AC power is not being received by the power receiving sensor and the temperature detected by the battery sensor is within a second range higher than the first range, does not perform the conversion of the second DC power and the supply to the second resonance circuit. A power receiving device.

2. The power receiving device according to claim 1, wherein the second resonance frequency is greater than the first resonance frequency. A power receiving device.

3. The power receiving device according to claim 1, further comprising, a current sensor in the input portion or the output portion of the power conversion circuit, the control circuit, controls the power conversion circuit based on the detection value of the current sensor such that a temperature - rising current based on the second resonance frequency becomes a predetermined reference current. A power receiving device.

4. A power receiving device (100x) that receives AC power non - contactlessly by a magnetic field, A resonance circuit (110) including a power receiving coil (111) that receives the AC power; A power conversion circuit (120x) that converts the AC power into DC power; A battery (130) that charges the DC power; A smoothing capacitor (170) connected in parallel between the power conversion circuit and the battery; A switch (Swx) connected in series to the smoothing capacitor; A battery sensor (160) that measures the temperature of the battery; A control circuit (150x) that controls the power receiving device, and comprising: The control circuit is configured to: When the battery sensor detects a first temperature included in a first range predetermined for the temperature, perform control to turn off the switch; A power receiving device that controls the switch to be in an on state when the battery sensor detects a second temperature included in a second range higher than the first range.

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