WO2020158559A1

WO2020158559A1 - Power receiving device

Info

Publication number: WO2020158559A1
Application number: PCT/JP2020/002266
Authority: WO
Inventors: 真登向山; 正樹金▲崎▼; 宜久山口
Original assignee: 株式会社デンソー
Priority date: 2019-02-01
Filing date: 2020-01-23
Publication date: 2020-08-06
Also published as: JP2020127269A

Abstract

This power receiving device (30) comprises: a secondary coil (31) which can receive power contactlessly from a primary coil (21); a capacitor (32) which is connected to the secondary coil (31) and which, together with the secondary coil 31, constitutes a resonant circuit (33); a power regulating circuit (40) which is provided between the load (17) and resonant circuit (33) and which regulates input power to the load (17); and a control device (50) which controls the power regulating circuit (40). The power regulating circuit (40) has a switch (42) which turns ON and OFF at a predetermined cycle. Input power to the load (17) is regulated by regulating the ON time of the switch (42) within a predetermined cycle. The control device (50) comprises: a distance calculation unit which calculates the clearance between the secondary coil (31) and the primary coil (21); and a time setting unit which sets the ON time of the switch (42), on the basis of the clearance.

Description

Power receiving device

Cross-reference of related applications

This application is based on Japanese application No. 2019-017424 filed on February 1, 2019, and the contents of the description are incorporated herein.

The present disclosure relates to a power receiving device that receives contactless AC power from a power transmitting device.

Conventionally, as a non-contact power transmission device that transmits power to the other party in a contactless manner without using a power cord or power transmission cable, one that uses magnetic field resonance or electromagnetic induction is known. For example, in Patent Document 1, a power receiving device is provided in a carrier vehicle traveling on a track such as in a factory, and power is supplied to the power receiving device from a primary power supply line arranged along a moving route of the carrier vehicle. The configuration is disclosed. In this power receiving device, the supplied power changes according to the load connected to the power receiving device. Therefore, this power receiving device is provided with a voltage control unit that controls the supplied power to a constant voltage.

JP, 2008-259419, A

By the way, a technology has been developed in which a power transmission device is embedded in a road and a power receiving device is provided in a vehicle traveling on the road to supply electric power to a moving vehicle in a contactless manner. In a vehicle traveling on a road, unlike a carrier vehicle traveling on a track in a factory or the like, a separation distance between a power receiving device and a power transmitting device changes depending on road conditions or vehicle conditions. When the distance between the power receiving device and the power transmitting device changes, the power transmission efficiency and the like change, so that the power input from the power receiving device to the load fluctuates. In order to cope with this fluctuation, it is necessary to increase the capacity on the load side or add components. Therefore, it is not desirable that the input power to the load fluctuates.

The present disclosure has been made in view of the above problems, and its main purpose is to provide a power receiving device that can appropriately cope with fluctuations in received power.

The means is a vehicle-mounted power receiving device that receives the AC power from a power transmitting device having a primary coil to which AC power is input and supplies power to a load, and can receive power from the primary coil in a contactless manner. A secondary coil, a capacitor that is connected to the secondary coil and configures a resonance circuit together with the secondary coil, and a power adjuster that is provided between the load and the resonance circuit and that adjusts input power to the load. A circuit and a control device that controls the power adjustment circuit, wherein the power adjustment circuit has a switch that is turned on and off in a predetermined cycle, and the on time of the switch within the predetermined cycle is adjusted. Thus, the input power to the load is adjusted, the distance calculation unit that calculates the separation distance between the secondary coil and the primary coil, and the ON time of the switch based on the separation distance. And a time setting unit for setting.

AC power is transmitted from the power transmitting device to the power receiving device by, for example, establishing magnetic field resonance between the primary coil and the secondary coil. The capacitor and the secondary coil are adjusted so that magnetic field resonance is established between the primary coil and the secondary coil. Then, the electric power received by the secondary coil is supplied to the load.

By the way, due to the change in the separation distance between the primary coil and the secondary coil, the efficiency of transmitting power from the power transmitting device to the power receiving device changes, and the received power varies. For example, when the vehicle is running, it is considered that the separation distance between the primary coil and the secondary coil is likely to change depending on road conditions and vehicle conditions. When the received power fluctuates, the input power to the load becomes unstable, so it is necessary to deal with the fluctuation of the received power. Further, when a power transmission device is provided on the road, various vehicles pass on the road, and therefore it is necessary to deal with fluctuations in the received power on the power receiving device side rather than on the power transmitting device side.

Therefore, on the power receiving device side, the separation distance between the primary coil and the secondary coil is calculated, and the on time of the switch of the power adjustment circuit is calculated based on this separation distance to adjust the input power to the load. As described above, by adjusting the input power to the load on the power receiving device side based on the change in the separation distance between the primary coil and the secondary coil, the input power to the load can be reduced even during traveling. Can be prevented from becoming unstable.

The above and other objects, features and advantages of the present disclosure will become more apparent by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a schematic configuration diagram of a contactless power transmission device according to an embodiment, FIG. 2 is an electric circuit diagram of the non-contact power transmission device, FIG. 3 is a flowchart for controlling the on-time, FIG. 4 is a diagram showing the relationship between the received power, the separation distance, and the battery voltage, FIG. 5 is a diagram showing the relationship between the received power, the separation distance, and the target power, FIG. 6 is a diagram showing a change in input power to a load due to a change in separation distance, FIG. 7 is an electric circuit diagram of a contactless power transmission device according to another embodiment.

<Embodiment>
The present embodiment is intended for a power receiving device mounted on a vehicle. FIG. 1 is a schematic configuration diagram of a contactless power transmission device 10 according to this embodiment. The vehicle 15 is, for example, an EV (electric vehicle) or PEV (plug-in hybrid vehicle) that is driven by an electric vehicle drive device (drive motor or the like).

The power transmitting device 20 performs power transmission (power supply) in a non-contact state with the power receiving device 30 mounted on the vehicle 15. The power transmission device 20 is installed on the ground G so as to be embedded in the ground G or exposed from the ground G. The power transmission devices 20 are provided, for example, on a traveling road of the vehicle 15, and are embedded side by side along the traveling direction of the vehicle 15. Further, the power transmission device 20 transmits power while the vehicle 15 is traveling.

The power transmission device 20 includes a primary coil 21. The primary coil 21 is formed by winding a winding (for example, a litz wire) around a core material such as a ferrite core in a planar shape. The primary coil 21 is arranged such that its axis is orthogonal to the ground G, that is, the plane wound in a plane is parallel to the ground G.

The power receiving device 30 includes a secondary coil 31, and the secondary coil 31 is attached to the vehicle body. More specifically, the secondary coil 31 is provided on the vehicle bottom portion 15a. The vehicle bottom portion 15a indicates a portion that forms a lower surface of the vehicle 15, such as a floor portion that forms a passenger compartment of the vehicle 15 and an undercover. The vehicle body means a portion of the vehicle 15 that includes the vehicle bottom portion 15a, the vehicle body frame, and the like.

The secondary coil 31 is formed by winding a winding (for example, a litz wire) around a core material such as a ferrite core in a flat shape. The secondary coil 31 is arranged so that its axis is orthogonal to the ground G, that is, the plane wound in a plane is parallel to the ground G and faces the primary coil 21 in parallel.

Further, the vehicle bottom portion 15a on the front end side is provided with a distance sensor 16 that detects a detection distance h1 between the ground G (traveling road surface) of the vehicle 15 and the vehicle bottom portion 15a. The distance sensor 16 is, for example, a laser type or ultrasonic type distance measuring sensor. The distance sensor 16 corresponds to a “detection unit”. The distance sensor 16 may be provided near the power receiving device 30 instead of the front end portion of the vehicle 15.

The power received by the power receiving device 30 is supplied to the storage battery 17. The storage battery 17 is, for example, a secondary battery (lithium ion battery, nickel hydrogen battery, or the like). The storage battery 17 stores the electric power supplied from the power receiving device 30 and supplies the electric power to the vehicle drive device.

The vehicle 15 is provided with an ECU 50 that is a control device for controlling the power receiving device 30. The ECU 50 is an electronic control device that includes a microcomputer having a CPU, ROM, RAM, and the like, and its peripheral circuits. The value detected by the distance sensor 16 is input to the ECU 50, and the monitoring status such as the SOC of the storage battery 17 is input. The ECU 50 may be provided at the same position as the secondary coil 31 or the like, or the ECU 50 may be provided at another position.

FIG. 2 is an electric circuit diagram of the contactless power transmission device 10. The contactless power transmission device 10 includes a power transmitting device 20 and a power receiving device 30. The power transmission device 20 includes a primary side resonance unit 23, a primary side filter circuit 24, an inverter 25, a converter 26, and a primary side drive circuit 27.

Electric power is supplied to the power transmitting device 20 from the power supply device 28. The power supply device 28 is an AC power supply that receives power from a power grid provided by a power company or the like. The power supply device 28 supplies AC power of about 50 kHz at three-phase 200V or 400V, for example.

The converter 26 is an AC/DC converter, which converts the AC power supplied from the power supply device 28 into DC power having a predetermined voltage, and converts the AC power into DC power by, for example, a switching method. The switching element of the converter 26 is driven by the primary side drive circuit 27.

The inverter 25 converts the DC power supplied from the converter 26 into AC power having a predetermined frequency. The inverter 25 converts a direct current into an alternating current having a predetermined frequency by switching the switching element. The switching element of the inverter 25 is driven by the primary side drive circuit 27.

A primary side filter circuit 24 is preferably provided between the inverter 25 and the primary side resonance section 23. The primary filter circuit 24 is a kind of low-pass filter that cuts high-frequency components. Specifically, the primary side filter circuit 24 is an immittance filter in which a coil, a capacitor, and a coil are connected in a T shape.

The primary side resonance unit 23 is a resonance circuit in which the primary coil 21 and the primary side capacitor 22 are connected in series. The primary side resonance part 23 resonates when AC power of a predetermined frequency is input, and transmits power to the secondary side resonance part 33.

The power receiving device 30 includes a secondary side resonance unit 33, a secondary side filter circuit 34, a rectifier 35, and a power adjustment circuit 40. The power receiving device 30 supplies power to the storage battery 17.

The secondary side resonance unit 33 is a resonance circuit in which the secondary coil 31 and the secondary side capacitor 32 are connected in series. It is desirable that the primary side resonance part 23 and the secondary side resonance part 33 are configured by the SS system. The secondary side resonance part 33 is adjusted so that magnetic field resonance is established between the secondary side resonance part 33 and the primary side resonance part 23. Specifically, it is desirable that the resonance frequency of the secondary side resonance section 33 matches the resonance frequency of the primary side resonance section 23.

Then, when the relative position between the power transmitting device 20 and the power receiving device 30 is in a position where magnetic field resonance is established, when AC power of a predetermined frequency is input from the inverter 25, the primary side resonance unit 23 (primary side). The coil 21) and the secondary side resonance part 33 (secondary coil 31) resonate with a magnetic field. As a result, the secondary side resonance unit 33 receives the AC power from the primary side resonance unit 23. The predetermined frequency of the AC power input from the inverter 25 may be a frequency at which power can be transmitted between the primary side resonance section 23 and the secondary side resonance section 33. Specifically, the predetermined frequency of the AC power generated by the inverter 25 is preferably set to the resonance frequency of the primary side resonance section 23 and the secondary side resonance section 33.

A secondary side filter circuit 34 is provided between the secondary side resonance unit 33 and the rectifier 35. The secondary side filter circuit 34 has the same configuration as the primary side filter circuit 24. The secondary filter circuit 34 is a kind of low-pass filter that cuts high-frequency components. Specifically, the secondary filter circuit 34 is an immittance filter in which a coil, a capacitor, and a coil are connected in a T shape. The immittance filter (secondary-side filter circuit 34) is an impedance-admittance converter, and is a filter configured such that the impedance seen from the input end of the immittance filter is proportional to the admittance of the load connected to the output end. is there.

The rectifier 35 has a known configuration for converting AC power into DC power. The rectifier 35 is composed of, for example, a diode bridge circuit including four diodes. The power output from the rectifier 35 is DC power obtained by full-wave rectifying the AC power.

The power converted into DC power by the rectifier 35 is input to the power adjustment circuit 40 that adjusts the input power W to the storage battery 17. The power adjustment circuit 40 includes a coil 41, a switch 42, a diode 43, and a capacitor 44. The power adjustment circuit 40 is a chopper circuit that allows the storage battery 17 to be energized from the secondary coil 31 side when the switch 42 is turned off. The switch 42 is a semiconductor switching element such as a MOSFET, and is driven by the secondary side drive circuit 45. By turning the switch 42 on and off, the amount of electric power flowing to the storage battery 17 side is adjusted. The switch 42 may be a mechanical switch instead of the semiconductor switching element. The power adjusting circuit 40 has the same circuit configuration as a so-called boost chopper circuit, but the output voltage depends on the battery voltage of the storage battery 17.

The secondary side drive circuit 45 controls on/off of the switch 42 at a predetermined frequency based on a command from the ECU 50. The switch 42 is controlled by PWM control in which the time for which the switch 42 is turned on in a predetermined cycle is controlled, and the output power is controlled by adjusting the on time (on duty) in a constant cycle.

By the way, when the power transmission device 20 is buried in a road and power is transmitted and received while the vehicle 15 is traveling, various vehicles pass on the road, so that the power transmission device 20 is not mounted on the road but on the vehicle. It is desirable for the device 30 side to handle changes in power transmission efficiency. Further, when the distance h2 between the primary coil 21 and the secondary coil 31 changes while the vehicle 15 is traveling, the efficiency of transmitting power from the power transmitting device 20 to the power receiving device 30 decreases, and the received power W0 increases. fluctuate.

Specifically, it is considered that when the vehicle 15 is running, the separation distance h2 between the primary coil 21 and the secondary coil 31 is likely to change depending on road conditions and vehicle conditions. Specifically, as the vehicle speed of the vehicle 15 increases, the running wind causes a change in the posture of the vehicle 15 and ups and downs of the vehicle 15, which causes the separation distance h2 to change. Due to the downforce applied to the vehicle 15, the vehicle 15 is lifted or pushed down according to the vehicle shape and the like. Further, as the vehicle 15 travels, the temperature of the tire rises, the gas pressure of the tire changes, and the tire diameter increases, which may increase the separation distance h2. Further, in the case of the vehicle 15 having the fuel tank, the vehicle height changes and the separation distance h2 changes as the weight of the fuel increases or decreases.

The change in the separation distance h2 between the primary coil 21 and the secondary coil 31 changes the power transmission efficiency for transmitting and receiving power from the power transmitting device 20 to the power receiving device 30, and the received power W0 fluctuates. When the received power W0 fluctuates, the input power W to the storage battery 17 becomes unstable. Further, the battery voltage changes depending on the usage status and the charging status of the storage battery 17. While the vehicle 15 is traveling, electric power is supplied from the storage battery 17 or charged, so that the battery voltage changes. Then, when the battery voltage changes, the received power W0 changes. When the received power W0 fluctuates, the input power W to the storage battery 17 becomes unstable.

Therefore, the ECU 50 of the present embodiment controls the on time of the switch 42 of the power adjustment circuit 40 so that the input power W to the storage battery 17 is adjusted within a predetermined range. The ECU 50 provided on the power receiving device 30 side, not on the power transmitting device 20 side, calculates the separation distance h2 between the primary coil 21 and the secondary coil 31, and based on the separation distance h2, the switch of the power adjustment circuit 40. The on time of 42 is calculated, and the input power W to the storage battery 17 is adjusted. Further, the ON time of the switch 42 in the power adjustment circuit 40 is adjusted so that the input power W to the storage battery 17 is constant with respect to the received power W0 that varies according to the battery voltage of the storage battery 17.

FIG. 3 is a flowchart for controlling the on time of the power adjustment circuit 40. This process is performed by the ECU 50 at a predetermined cycle.

In S11, the detection distance h1 between the vehicle bottom 15a and the ground G detected by the distance sensor 16 is acquired. Based on the detection distance h1 acquired in S11, the separation distance h2 between the primary coil 21 and the secondary coil 31 is calculated in S12. Specifically, the detection distance h1 is corrected and the separation distance h2 is calculated based on a predetermined distance between the ground G and the power transmitting device 20 and a difference in mounting height between the distance sensor 16 and the power receiving device 30. To do. The separation distance h2 is preferably calculated based on the average value of the detection distance h1 for a predetermined time, for example, several seconds to several tens of seconds, instead of an instantaneous value. By doing so, it is possible to eliminate the influence of a detection error and a small step on the ground G. Note that the separation distance h2 may be calculated by eliminating an instantaneous change in the instantaneous value with a filter or the like. Note that S12 corresponds to the "distance calculation unit".

In S13, the battery voltage of the storage battery 17 is acquired. The battery voltage of the storage battery 17 calculated based on the SOC of the storage battery 17 or the like is acquired. Note that S13 corresponds to the "voltage acquisition unit".

In S14, the received power W0 received by the power receiving device 30 is calculated based on the separation distance h2 and the battery voltage. Specifically, the received power W0 is calculated from the separation distance h2 and the battery voltage based on a map set in advance by experiments as shown in FIG. For example, when the separation distance h2 is 150 mm and the battery voltage is low, the received power W0 is α [W].

Note that the received power W0 decreases as the distance h2 increases. Further, the higher the battery voltage, the larger the received power W0. The secondary side resonance unit 33 receives power by the SS method, and the power output from the secondary side filter circuit 34 is a constant current. On the other hand, the voltage input to the storage battery 17 increases as the battery voltage increases. Therefore, the received power W0 increases as the battery voltage increases. Note that, as shown in FIG. 5, the received power W0 is larger than the target power Wt of the input power W input to the storage battery 17.

In S15, the on time of the switch 42 is calculated. The on-time (on-duty) is calculated based on the target power Wt and the received power W0 set so that the input power W input to the storage battery 17 falls within a predetermined range. Specifically, the on-duty is calculated by the formula 1-(Wt/W0). Based on the calculated on-duty, the secondary-side drive circuit 45 is controlled to control the on-time of the switch 42, and the process ends. Note that S15 corresponds to the "time setting unit".

FIG. 6 is a diagram showing changes in the received power W0 and the input power W to the storage battery 17 due to changes in the separation distance h2. The broken line shows the change in the separation distance h2 depending on the running time. By setting the on-time based on the separation distance h2 and the battery voltage, the electric power input to the storage battery 17 is adjusted within a predetermined range. When the distance h2 between the power receiving device 30 and the power transmitting device 20 increases due to a change in tire pressure while the vehicle 15 is running, the power receiving power W0 received by the power receiving device 30 from the power transmitting device 20 decreases. In this case, the ON time of the switch 42 is reduced so that the ratio of the input power W to the received power W0 is increased. On the other hand, when the separation distance h2 becomes small due to the decrease in vehicle height due to the increase in vehicle speed or the like, the power transmission efficiency improves and the received power W0 increases. In this case, the on time of the switch 42 is increased so that the input power W is within a predetermined range, and the input power W is controlled so that the ratio of the input power W to the received power W0 becomes small.

Also, if the battery voltage is high, the received power W0 will be high. In this case, the on time of the switch 42 is increased so that the input power W is within a predetermined range, and the input power W is controlled so that the ratio of the input power W to the received power W0 becomes small. On the other hand, when the battery voltage is low, the on time of the switch 42 is reduced so that the ratio of the input power W to the received power W0 is increased.

In this way, the on time of the switch 42 is adjusted so that the input power W to the storage battery 17 falls within a predetermined range even if the separation distance h2 and the battery voltage change. As a result, even if the received power W0 fluctuates, the input power W to the storage battery 17 becomes stable and deterioration of the storage battery 17 can be suppressed. Further, as a charging system having the power receiving device 30 and the storage battery 17, it is not necessary to prepare a sufficient capacity of the storage battery 17, so that the physique and weight of the charging system can be reduced and the cost can be reduced.

The following effects are achieved in this embodiment described above.

On the power receiving device 30 side, the separation distance h2 between the primary coil 21 and the secondary coil 31 is calculated, and the on time of the switch 42 of the power adjustment circuit 40 is calculated based on this separation distance h2, and the storage battery 17 The input power W is adjusted. As described above, by adjusting the input power W to the storage battery 17 based on the change in the separation distance h2 between the power reception device 30 and the power transmission device 20 on the power reception device 30 side, the storage battery is tentatively running. It is possible to prevent the input power W to 17 from becoming unstable.

The on time of the switch 42 is set such that the energization time to the storage battery 17 side becomes longer as the separation distance h2 becomes larger. When the separation distance h2 becomes large and the power transmission efficiency deteriorates, the energization time to the storage battery 17 side is lengthened so that the input power W to the storage battery 17 falls within a predetermined range. On time is adjusted. Thereby, the fluctuation of the input power W to the storage battery 17 can be suppressed.

The separation distance h2 between the primary coil 21 and the secondary coil 31 provided on the vehicle bottom portion 15a of the vehicle 15 changes while the vehicle 15 is traveling. For example, in the vehicle 15, it is conceivable that the tire pressure may increase and the tire diameter may change due to the temperature change of the tire due to continuous running. As the tire diameter changes, the distance h2 between the primary coil 21 and the secondary coil 31 changes during traveling. In this respect, the detection distance h1 between the vehicle bottom portion 15a and the traveling road surface (ground G) is detected, and the separation distance h2 between the primary coil 21 and the secondary coil 31 is calculated based on the detection distance h1. Then, by adjusting the ON time of the switch 42 based on the separation distance h2, it is possible to cope with such a change in the received power W0 accompanying the change in the separation distance h2 during traveling.

The battery voltage varies depending on the usage status and charging status of the storage battery 17. When the battery voltage of the storage battery 17 changes, the received power W0 changes. Therefore, the on time of the switch 42 in the power adjustment circuit 40 is adjusted so that the input power W to the storage battery 17 is within a predetermined range even if the received power W0 changes. By adjusting the on time of the switch 42 based on the battery voltage and the separation distance h2, the input power W to the storage battery 17 can be set within a predetermined range, and fluctuations can be suppressed.

<Other Embodiments>
The present disclosure is not limited to the above embodiment, and may be implemented as follows, for example.

As the electric power adjustment circuit 140, as shown in FIG. 7, a chopper circuit may be used that allows the storage battery 17 to be energized from the secondary coil 31 side by turning off the switch 42. The power adjustment circuit 140 includes a step-down coil 141, a switch 142, a diode 143, and a capacitor 144. The switch 142 is a semiconductor switching element such as a MOSFET, and is driven by the secondary side drive circuit 45. By turning the switch 42 on and off, the amount of electric power flowing to the storage battery 17 side is adjusted. The power adjustment circuit 140 has the same circuit configuration as a so-called step-down chopper circuit, but the output voltage depends on the battery voltage of the storage battery 17.

When the power adjustment circuit 140 performs the power adjustment and, for example, the separation distance h2 becomes small, the ON time of the switch 142 is reduced so that the input power W is within a predetermined range, and the input power W is reduced. Control is performed so that the ratio of the received power to W0 is small. On the other hand, when the separation distance h2 becomes large, the ON time of the switch 142 is increased so that the ratio of the input power W to the received power W0 is controlled to be large.

When the battery voltage is high, the ON time of the switch 142 is reduced so that the input power W is within a predetermined range, and the ratio of the input power W to the received power W0 is controlled to be small. To do. On the other hand, when the battery voltage is low, the on-time of the switch 142 is increased so that the ratio of the input power W to the received power W0 is increased.

In the above embodiment, the received power W0 is calculated based on the battery voltage and the separation distance h2, but the received power W0 may be calculated only based on the separation distance h2. In this case, the relationship between the separation distance h2 and the received power W0 may be calculated in advance by a map or a formula, and the received power W0 may be calculated based on the separation distance h2 calculated in S12.

The load connected to the power receiving device 30 may be a drive device (for example, a drive motor) or the like instead of the storage battery 17.

-The power receiving device may be provided on the side of the vehicle. In this case, the power transmission device may be embedded in a guardrail or the like arranged on the side of the road.

Although the present disclosure has been described according to the embodiments, it is understood that the present disclosure is not limited to the embodiments and the structure. The present disclosure also includes various modifications and modifications within an equivalent range. In addition, various combinations and forms, and other combinations and forms including only one element, more, or less than them are also within the scope and spirit of the present disclosure.

Claims

An in-vehicle power receiving device (30) for receiving the alternating current power from a power transmitting device (20) having a primary coil (21) to which alternating current power is input and supplying the power to a load (17),
A secondary coil (31) capable of receiving power from the primary coil in a non-contact manner,
A capacitor (32) connected to the secondary coil and forming a resonance circuit (33) together with the secondary coil;
A power adjusting circuit (40) provided between the load and the resonance circuit for adjusting the input power to the load,
A control device (50) for controlling the power adjustment circuit,
The power adjusting circuit has a switch (42) that is turned on and off in a predetermined cycle, and the input power to the load is adjusted by adjusting the on time of the switch within the predetermined cycle. ,
The control device is
A distance calculation unit that calculates a separation distance between the secondary coil and the primary coil;
A time setting unit that sets the ON time of the switch based on the separation distance;
Power receiving device having.
The power adjustment circuit enables energization of the load from the secondary coil side by turning on and off the switch,
The power receiving device according to claim 1, wherein the time setting unit sets the ON time of the switch such that the energization time to the load side becomes longer as the separation distance is larger.
It is applied to a vehicle (15) provided with a detection unit (16) for detecting the distance between the road surface of the vehicle 15 and the vehicle body,
The secondary coil is provided on the vehicle body,
The power receiving device according to claim 1, wherein the distance calculation unit calculates a separation distance between the secondary coil and the primary coil based on a distance detected by the detection unit.
When the switch is turned off, the power adjustment circuit enables energization of the load from the secondary coil side,
The power receiving device according to claim 1, wherein the time setting unit decreases the ON time of the switch as the separation distance increases.
The load is a rechargeable storage battery,
It has a voltage acquisition unit for acquiring the battery voltage of the storage battery,
The power receiving device according to any one of claims 1 to 4, wherein the time setting unit sets the on time of the switch in consideration of the battery voltage.
When the switch is turned off, the power adjustment circuit enables energization of the load from the secondary coil side,
The power receiving device according to claim 5, wherein the time setting unit increases the ON time of the switch as the battery voltage increases.