WO2020145167A1

WO2020145167A1 - Contactless power supply system

Info

Publication number: WO2020145167A1
Application number: PCT/JP2019/051012
Authority: WO
Inventors: 統公木村; 宜久山口; 正樹金▲崎▼
Original assignee: 株式会社デンソー
Priority date: 2019-01-10
Filing date: 2019-12-25
Publication date: 2020-07-16
Also published as: JP2020114092A

Abstract

In a contactless power supply system (10), a transmission device (20) is provided with an inverter (22), a transmission-side filter circuit (23), and a transmission-side resonant circuit (24) having transmission-side resonant coils (24Lu, 24Lv, 24Lw), and transmission-side resonant capacitors (24Cu, 24Cv, 24Cw). A reception device (30) is provided with a reception-side resonant circuit (31) having reception-side resonant coils (31Lu, 31Lv, 31Lw) and reception-side resonant capacitors (31Cu, 31Cv, 31Cw), a reception-side filter circuit (32), a rectifier (33), and a diode (34). The transmission-side filter circuit, the transmission-side resonant circuit, the reception-side resonant circuit, and the reception-side filter circuit are configured so that voltage outputted from the reception-side filter circuit is proportional to voltage inputted to the transmission-side filter circuit.

Description

Contactless power supply system

Cross-reference of related applications

This application is based on Japanese application No. 2019-002950 filed on January 10, 2019, the content of which is incorporated herein by reference.

The present disclosure relates to a contactless power supply system that wirelessly transmits power from a power transmitting device to a power receiving device.

There is a contactless power supply system that supplies power in a non-contact manner as a system that supplies power to a secondary battery installed in an electric vehicle or the like. In the contactless power supply system, an inverter circuit is provided on the power transmission device side, and AC power is supplied from the inverter circuit to the power transmission unit (primary coil). Then, the power is transmitted from the power transmitting unit to the power receiving unit (secondary coil) on the vehicle side in a non-contact manner, and the power receiving unit supplies power to the secondary battery.

The contactless power supply system of Patent Document 1 includes a DC-DC converter as an impedance conversion unit that sets impedance in correspondence with the output power value of AC power. As a result, it is possible to follow changes in the impedance of the load within a range where an excessive load is not applied to the DC-DC converter.

JP, 2016-63726, A

By the way, in recent years, a contactless power supply system has been devised to enable contactless power supply while the vehicle is traveling. When non-contact power feeding is performed while the vehicle is running, a reception delay occurs. Therefore, it is difficult to receive the output power value of the AC power and set the impedance as described above.

The present disclosure has been made in view of the above circumstances, and its main purpose is to provide a contactless power feeding system that can appropriately feed power while a vehicle is traveling.

Means for solving the above-mentioned problem is a non-contact power supply system that performs non-contact power feeding between a power transmission device provided on a road side and a power receiving device provided on a vehicle side to charge a storage battery provided in the vehicle. The power transmitting device includes an inverter that converts a direct current input from a direct current power source into an alternating current, a power transmitting side filter circuit that is connected to the inverter and removes an alternating current in a predetermined frequency range, and a power transmitting side resonance coil. And a power transmission side resonance circuit having a power transmission side resonance capacitor connected to the power transmission side resonance coil, wherein the power reception device has a power reception side resonance coil and a power reception side resonance capacitor connected to the power reception side resonance coil. Power-reception-side resonance circuit, connected to the power-reception-side resonance circuit, and connected to the power-reception-side filter circuit that removes the alternating current in a predetermined frequency range, and the power-reception-side filter circuit, and convert the alternating current into a direct current. A rectifier that rectifies, and a diode that is connected in series to the rectifier and that allows a current to flow from the rectifier to the output terminal of the power receiving device, the power transmission side filter circuit, the power transmission side resonance circuit, Each of the power receiving side resonance circuit and the power receiving side filter circuit is configured such that an input voltage to the power transmitting side filter circuit and an output current from the power receiving side filter circuit are proportional to each other.

When contactless power supply is performed while the vehicle is running, it is difficult to communicate between the power transmitting device and the power receiving device due to communication delay. Therefore, the power transmission device supplies a predetermined amount of power regardless of the state of the vehicle, that is, the state of the storage battery. In this case, in consideration of shortening the charging time, it is preferable that the supplied power be as large as possible.

On the other hand, when configured in this way, it is necessary to adjust the power on the power receiving device side. For example, it can be considered that the output power (DC current) from the rectifier is adjusted by a booster circuit such as a DC-DC converter according to the required power of the storage battery. In particular, when the output power from the rectifier is a constant voltage, the current may be interrupted, so it is necessary to provide a booster circuit.

However, in a power feeding system that feeds a large amount of electric power like a vehicle, the inductor of the DC-DC converter becomes large. As a result, there is a problem that the power receiving device becomes large even though the accommodation space is limited.

Therefore, each circuit of the power transmission side filter circuit, the power transmission side resonance circuit, the power reception side resonance circuit, and the power reception side filter circuit is configured so that the input voltage to the power transmission side filter circuit and the output current from the power reception side filter circuit are proportional to each other. ..

With this, the output voltage from the inverter is proportional to the output current of the rectifier. Therefore, if the output voltage from the inverter is constant, the output current of the rectifier can be made constant. Then, if the current is a constant current, the current is not interrupted, and it is not necessary to provide an inductor between the rectifier and the diode. Therefore, the inductor can be omitted or downsized, and the power receiving device can be downsized. In addition, it is possible to appropriately supply power while the vehicle is traveling.

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 circuit diagram showing an electrical configuration of a contactless power supply system, FIG. 2 is a flowchart showing power reception control processing, FIG. 3 is a circuit diagram showing a comparative example of the contactless power feeding system, FIG. 4 is a time chart showing the current waveform, FIG. 5 is a circuit diagram showing an electrical configuration of a non-contact power feeding system in another example, FIG. 6 is a circuit diagram showing an electrical configuration of a non-contact power feeding system in another example, FIG. 7: is a circuit diagram which shows the electric constitution of the non-contact electric power feeding system in another example.

The contactless power supply system 10 according to the present embodiment includes a power transmission device 20 that transmits power supplied from a commercial power supply 11 in a contactless manner, and a power reception device 30 that receives power from the power transmission device 20 in a contactless manner. The power transmission device 20 is embedded on the road side (highway or the like) on which the vehicle travels. The power receiving device 30 is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and outputs electric power to the vehicle-mounted battery 12 as a storage battery to charge the vehicle-mounted battery 12.

FIG. 1 shows an electrical configuration of the contactless power feeding system 10 in this embodiment. A commercial power supply 11 is connected to the power transmission device 20 of the contactless power supply system 10, and is configured to input the AC power supplied from the commercial power supply 11 to the power transmission device 20. On the other hand, the in-vehicle battery 12 is connected to the power receiving device 30 of the contactless power supply system 10, and the power receiving device 30 outputs power to the in-vehicle battery 12 to perform charging. The power transmitting device 20 and the power receiving device 30 each have coils of three phases (U phase, V phase, W phase) so that three-phase power feeding can be performed.

First, the power transmission device 20 will be described. The power transmission device 20 includes an AC-DC converter 21 connected to the commercial power supply 11, an inverter circuit 22 as an inverter connected to the AC-DC converter 21, a power transmission-side filter circuit 23 connected to the inverter circuit 22, The power transmission side resonance circuit 24 connected to the power transmission side filter circuit 23.

The AC-DC converter 21 converts AC power supplied from the commercial power supply 11 into DC power. Then, the AC-DC converter 21 outputs the converted DC power to the inverter circuit 22. Therefore, when viewed from the inverter circuit 22, the AC-DC converter 21 corresponds to a DC power supply.

The inverter circuit 22 as an inverter converts the DC power supplied from the AC-DC converter 21 into AC power of a predetermined frequency. As this inverter circuit 22, a three-phase inverter that converts three-phase AC power of U phase, V phase, and W phase is used.

The inverter circuit 22 is connected to the AC-DC converter 21. Specifically, the high potential side terminal of the inverter circuit 22 is connected to the positive terminal of the AC-DC converter 21. On the other hand, the low potential side terminal of the inverter circuit 22 is connected to the negative terminal of the AC-DC converter 21.

The inverter circuit 22 is composed of a full bridge circuit having the same number of upper and lower arms as the number of three phases. The current in each phase is adjusted by turning on/off the switching element provided in each arm.

Describing in detail, the inverter circuit 22 includes a series connection body of an upper arm switch Sp and a lower arm switch Sn as switching elements in each of the three phases including the U phase, the V phase, and the W phase. In this embodiment, a voltage-controlled semiconductor switching element is used as the upper arm switch Sp and the lower arm switch Sn in each phase, and specifically, an IGBT is used. A MOSFET may be used. Free wheel diodes (reflux diodes) Dp and Dn are connected in antiparallel to the upper arm switch Sp and the lower arm switch Sn in each phase, respectively.

The high-potential side terminal (collector) of the upper arm switch Sp of each phase is connected to the positive terminal of the AC-DC converter 21. Further, the low potential side terminal (emitter) of the lower arm switch Sn of each phase is connected to the negative terminal (ground) of the AC-DC converter 21. Intermediate connection points between the upper arm switch Sp and the lower arm switch Sn of each phase are connected to the power transmission side filter circuit 23, respectively.

That is, the intermediate connection point between the upper arm switch Sp and the lower arm switch Sn in the U phase is connected to the U phase power transmission side resonance coil 24Lu of the power transmission side resonance circuit 24 via the power transmission side filter circuit 23 and the like. Has been done. Similarly, an intermediate connection point between the upper arm switch Sp and the lower arm switch Sn in the V phase is connected to the V phase power transmission side resonance coil 24Lv of the power transmission side resonance circuit 24 via the power transmission side filter circuit 23 and the like. It is connected. Similarly, at the intermediate connection point between the upper arm switch Sp and the lower arm switch Sn in the W phase, the power transmission side resonance circuit 24Lw is connected to the W phase power transmission side resonance coil 24Lw of the power transmission side resonance circuit 24 via the power transmission side filter circuit 23 and the like. It is connected.

The power transmission side filter circuit 23 is a circuit that removes AC power (AC current) in a predetermined frequency range from AC power input from the inverter circuit 22. A low pass filter is used as the power transmission side filter circuit 23. In the present embodiment, the power transmission side filter circuit 23 is an immittance converter (impedance admittance converter) in which the input voltage is proportional to the output current and the input current is proportional to the output voltage.

Specifically, the power transmission side filter circuit 23 includes a series connection body in which two reactors 23a and 23b are connected in series for each phase. Further, the power transmission side filter circuit 23 includes a capacitor 23c, one end of which is connected to the intermediate connection point of each series connection body, for each series connection body. The other end of each capacitor 23c is connected at a connection point (neutral point) N1. That is, the other ends of the capacitors 23c are connected to each other.

The power transmission side resonance circuit 24 is a circuit that outputs the AC power input from the power transmission side filter circuit 23 to the power receiving device 30. The power transmission side resonance circuit 24 is provided with an LC resonance circuit in which the power transmission side resonance capacitors 24Cu, 24Cv, 24Cw and the power transmission side resonance coils 24Lu, 24Lv, 24Lw are connected in series for each phase. One end of the LC resonance circuit is connected to the power transmission side filter circuit 23, and the other end is connected to the neutral point N2.

The power receiving device 30 serves as a power receiving side resonance circuit 31 supplied with power from the power transmitting side resonance circuit 24, a power receiving side filter circuit 32 connected to the power receiving side resonance circuit 31, and a rectifier connected to the power receiving side filter circuit 32. The rectifier circuit 33, the diode 34 connected to the rectifier circuit 33, the switch unit 35 connected to the rectifier circuit 33, and the capacitor 36 connected to the diode 34.

The power receiving side resonance circuit 31 is a circuit that inputs power from the power transmitting side resonance circuit 24 in a non-contact manner and outputs the power to the power receiving side filter circuit 32. The power receiving side resonance circuit 31 has the same configuration as the power transmission side resonance circuit 24, and is configured to be capable of magnetic field resonance with the power transmission side resonance circuit 24.

That is, the power receiving side resonance circuit 31 is provided with an LC resonance circuit in which the power receiving side resonance capacitors 31Cu, 31Cv, 31Cw and the power receiving side resonance coils 31Lu, 31Lv, 31Lw are connected in series for each phase. One end of the LC resonance circuit is connected to the neutral point N3, and the other end is connected to the power receiving side filter circuit 32. The resonance frequencies of the power receiving side resonance circuit 31 and the power transmission side resonance circuit 24 are set to be the same.

The power receiving side filter circuit 32 removes AC power in a predetermined frequency range included in the AC power input from the power receiving side resonance circuit 31. A low pass filter is used as the power receiving side filter circuit 32. In the present embodiment, the power receiving side filter circuit 32 is an immittance converter (impedance admittance converter) in which the input voltage is proportional to the output current and the input current is proportional to the output voltage.

Specifically, the power receiving side filter circuit 32 includes a series connection body in which two reactors 32a and 32b are connected in series for each phase. Further, the power receiving side filter circuit 32 includes a capacitor 32c, one end of which is connected to the intermediate connection point of each series connection body, for each series connection body. The other end of each capacitor 32c is connected at a connection point (neutral point) N4. That is, the other ends of the capacitors 32c are connected to each other.

The rectifier circuit 33 is a circuit for full-wave rectifying AC power. In the present embodiment, the full-wave rectifier circuit including the diode bridge is adopted as the rectifier circuit 33, but a synchronous rectifier circuit including six switching elements (for example, MOSFETs) may be used.

The diode 34 is connected in series to (the output terminal of) the rectifying circuit 33, and permits the current flowing from the rectifying circuit 33 to the output terminal 30a of the power receiving device 30. Note that no reactance or the like is connected between the diode 34 and the rectifier circuit 33, and the diode 34 is directly connected to the rectifier circuit 33.

The switch unit 35 is a switching element that switches between energization and de-energization between the rectifier circuit 33 and the ground terminal. As the switch unit 35, a voltage control type semiconductor switching element is used, and specifically, an IGBT is used. A MOSFET may be used. Free wheel diodes (free wheeling diodes) are connected to the switch portions 35 in antiparallel. The switch unit 35 is connected in parallel to the rectifier circuit 33. That is, one end of the switch unit 35 is connected to the high potential side terminal of the rectifier circuit 33. More specifically, one end of the switch unit 35 is connected to a connection point N5 on the path connecting the diode 34 and the rectifier circuit 33. The other end of the switch unit 35 is connected to the low potential side terminal of the rectifier circuit 33.

The capacitor 36 has one end connected to a connection point N6 on the electric path between the diode 34 (cathode of the diode) and the output terminal 30a of the power receiving device 30, and the other end connected to the ground terminal.

The output terminal 30a on the high potential side of the power receiving device 30 is connected to the anode terminal of the vehicle-mounted battery 12, and the output terminal 30b on the low potential side is connected to the negative terminal of the vehicle-mounted battery 12. The in-vehicle battery 12 charges the DC power input from the power receiving device 30.

Further, the power transmission device 20 is provided with a power transmission control unit 60 that controls the power transmission device 20, and the power reception device 30 is provided with a power reception control unit 70 that controls the power reception device 30. The power transmission control unit 60 controls the AC-DC converter 21 and the inverter circuit 22. The power reception control unit 70 controls the switch unit 35.

Further, the vehicle is provided with an ECU 50 (Electronic Control Unit), which instructs the power reception control unit 70 to perform non-contact power supply while the vehicle is traveling and charge the in-vehicle battery 12. Specifically, the ECU 50 acquires the state (voltage, temperature, etc.) of the vehicle-mounted battery 12 and calculates the required power. Then, the ECU 50 outputs the calculated required power as a command value to the power reception control unit 70. The power reception control unit 70 controls the switch unit 35 based on the command value.

According to the above configuration, in a situation where the relative positions of the power transmitting device 20 and the power receiving device 30 are in positions where magnetic field resonance is possible, when AC power is input to the power transmitting resonance coils 24Lu, 24Lv, 24Lw, the power transmitting resonance coil 24Lu. , 24Lv, 24Lw and the power receiving side resonance coils 31Lu, 31Lv, 31Lw resonate with each other in the magnetic field. As a result, the power receiving device 30 receives a part of the energy from the power transmitting device 20. That is, AC power is received. In the present embodiment, for convenience of description, it is assumed that the relative positions of the power transmitting device 20 and the power receiving device 30 are at positions where magnetic field resonance is possible.

By the way, the non-contact power feeding system 10 is intended to enable non-contact power feeding while the vehicle is traveling. Therefore, communication between the power transmitting device 20 and the power receiving device 30 may cause communication delay, and thus communication such as transmission/reception of required power is not performed in principle.

For this reason, the power transmission device supplies a predetermined amount of power regardless of the state of the vehicle, that is, the state of the storage battery. In this case, it is preferable that the supplied power be as large as possible in consideration of shortening the charging time and the relative positions of the power transmitting device and the power receiving device deviating from the ideal state. Therefore, in the present embodiment, the power transmission device 20 is configured to supply the maximum power that can be output. Specifically, the power transmission control unit 60 sets the drive duty of the inverter circuit 22 to a fixed value such as full duty.

However, when the maximum power is supplied, it may not be necessary depending on the required voltage of the vehicle-mounted battery 12 on the power receiving device 30 side. That is, there is a possibility that excessive power is supplied with respect to the required power. When the vehicle-mounted battery 12 is overcharged or is deteriorated when it is charged with excessive electric power. In addition, there is a problem that the inter-coil coupling coefficient fluctuates due to the positional deviation of the power transmission device 20 and the power reception device 30 and the fluctuation of the inter-coil distance, and thus the output power fluctuates. Therefore, it is necessary to adjust the output power to the vehicle-mounted battery 12 on the power receiving device 30 side.

Therefore, conventionally, it has been considered to provide a booster circuit such as a DC-DC converter between the rectifier circuit 33 and the vehicle-mounted battery 12. Then, the output power (DC current) from the rectifier circuit 33 is boosted according to the required power of the vehicle-mounted battery 12. As a result, stable power is supplied to the vehicle-mounted battery 12 according to the required power.

However, in a non-contact power feeding system that feeds a large amount of electric power like a vehicle, the reactance of the DC-DC converter becomes large. As a result, there is a problem that the power receiving device becomes large even though the accommodation space is limited. On the other hand, if the reactance is eliminated, there is a problem that if the output power from the rectifier circuit 33 is not a constant current, the current is interrupted and stable output power cannot be supplied.

Therefore, the power transmission side filter circuit 23, the power transmission side resonance circuit 24, the power reception side resonance circuit 31 path, and the power reception side filter circuit are arranged so that the input voltage to the power transmission side filter circuit 23 and the output current from the power reception side filter circuit 32 are proportional to each other. 32 circuits were constructed.

Specifically, the power transmitting side filter circuit 23 and the power receiving side filter circuit 32 are configured by immittance converters in which the input voltage is proportional to the output current and the input current is proportional to the output voltage. In the power transmission side resonance circuit 24, the power transmission side resonance coils 24Lu, 24Lv, 24Lw are configured such that the power transmission side resonance capacitors 24Cu, 24Cv, 24Cw are connected in series. In the power receiving side resonance circuit 31, the power receiving side resonance coils 31Lu, 31Lv, 31Lw are configured such that the power receiving side resonance capacitors 31Cu, 31Cv, 31Cw are connected in series. That is, the primary side series secondary side series SS system coil is used. In the SS method, a constant current is output.

The following formula is used to show that the input voltage to the power transmitting side filter circuit 23 and the output current from the power receiving side filter circuit 32 are proportional to each other with the above configuration. Although only the U phase is shown in the present embodiment, the same applies to the V phase and the W phase. Equation (1) shows the impedance of the power transmission side filter circuit 23. The impedance of the power transmission side filter circuit 23 is indicated by Xc1, the capacitance of the capacitor 23c is indicated by C11, the impedance of the reactor 23a is indicated by L11, and the impedance of the reactor 23b is indicated by L12. The drive frequency of the inverter circuit 22 is indicated by ω.

Further, the equation (2) shows the impedance of the power receiving side filter circuit 32. The impedance of the power receiving side filter circuit 32 is indicated by Xc2, the capacitance of the capacitor 32c is indicated by C21, the impedance of the reactor 32a is indicated by L21, and the impedance of the reactor 32b is indicated by L22. The drive frequency (angular frequency) of the inverter circuit 22 is indicated by ω.

Then, Equation (3) shows the mutual inductance between the power transmitting side resonance coil 24Lu and the power receiving side resonance coil 31Lu and the impedance thereof. The mutual inductance between the power receiving side resonance coil 31Lu is indicated by Lm, and its impedance is indicated by Xm.

Further, in the equation (4), the relationship between the power transmission side resonance coil 24Lu and the power transmission side resonance capacitor 24Cu in the power transmission side resonance circuit 24, and the relationship between the power reception side resonance coil 31Lu and the power reception side resonance capacitor 31Cu in the power reception side resonance circuit 31. Indicates. The impedance of the power transmission resonance coil 24Lu is shown by L1, and the capacitance of the power transmission resonance capacitor 24Cu is shown by Cs1. The impedance of the power receiving resonance coil 31Lu is indicated by L2, and the capacitance of the power receiving resonance capacitor 31Cu is indicated by Cs2. In addition, the relationship between the resonance frequency and the drive frequency of the inverter circuit 22 at the time of resonance is shown in Expression (5). The resonance frequency is indicated by f0, and the drive frequency of the inverter circuit 22 at the time of resonance is indicated by ω0.

Then, as described above, the power transmitting side filter circuit 23 and the power receiving side filter circuit 32 are configured by immittance converters in which the input voltage and the output current are proportional and the input current and the output voltage are proportional. Therefore, the relationships between the input voltage and the input current to the power transmitting side filter circuit 23 and the output voltage and the output current from the power receiving side filter circuit 32 are as shown in Formulas (6) to (8). The input voltage to the power transmission side filter circuit 23 is V1, and the input current is I1. The output voltage from the power receiving side filter circuit 32 is V2, and the output current is I2. The input voltage and the input current to the power transmission side filter circuit 23 can be said to be the output voltage and the output current from the inverter circuit 22. It can be said that the output voltage and the output current from the power receiving side filter circuit 32 are the input voltage and the input current to the rectifier circuit 33.

Therefore, the relationship between the output voltage of the inverter circuit 22 and the input current to the rectifier circuit 33 is as shown in Expression (9). That is, the output voltage of the inverter circuit 22 and the input current to the rectifier circuit 33 have a proportional relationship.

Therefore, if the output voltage of the inverter circuit 22 is a constant voltage, the input current to the rectifier circuit 33 is a constant current. Since the output power from the rectifier circuit 33 is a constant current, even if the reactance between the rectifier circuit 33 and the diode 34 is deleted, the current will not be interrupted.

Next, power reception control processing by the power reception control unit 70 will be described based on FIG. The power reception control process is executed by the power reception control unit 70 at predetermined intervals.

First, the power reception control unit 70 acquires the command value of the required power from the ECU 50 (step S101). Next, the power reception control unit 70 acquires the value of the output voltage from the voltage sensor and the value of the output current from the current sensor (step S102). The value of the output voltage acquired in step S102 is the voltage value between the output terminal 30a on the high potential side and the output terminal 30b on the low potential side. The value of the output current acquired in step S102 is the value of the current flowing in the electrical path between the low potential side output terminal 30b and the low potential side terminal of the rectifier circuit 33. Then, the power reception control unit 70 calculates the chargeable power based on the obtained output voltage value and output current value.

Next, the power reception control unit 70 compares the chargeable power with the required power and controls the switch unit 35 (step S103). That is, the power reception control unit 70 determines the on/off duty ratio of the switch unit 35 based on the difference between the chargeable power and the required power, and controls the switch unit 35. At that time, it is desirable to perform feedback control such as PI control.

Explain the operation when the above configuration is adopted and the above power reception control is performed.

First, FIG. 3 shows a comparative example with respect to the circuit in this embodiment. In the circuit of the comparative example, the inductor 10L for the step-up chopper (for energy storage) is provided between the rectifier circuit 33 and the diode 34, and the smoothing capacitor 10C is provided. In this case, an output current having an ideal current waveform as shown in FIG. 4A can be obtained. However, since the inductor 10L is provided, the power receiving device 30 may become large.

On the other hand, when the inductor 10L and the smoothing capacitor 10C between the rectifier circuit 33 and the diode 34 are removed as shown in FIG. 1, an output current having a current waveform as shown in FIG. 4B can be obtained. As shown in FIG. 4, by removing the inductor 10L and the smoothing capacitor 10C, although the output current fluctuates (pulsates), it is possible to obtain a substantially constant output current without interruption. That is, it is possible to remove the inductor 10L, reduce the size of the power receiving device 30, and supply the output power suitable for charging the in-vehicle battery 12.

The effects of this embodiment will be described below.

When contactless power feeding is performed while the vehicle is traveling, it is difficult to perform communication between the power transmitting device 20 and the power receiving device 30 due to communication delay. Therefore, the power transmission device 20 supplies a predetermined electric power (maximum electric power in the present embodiment) regardless of the state of the vehicle side, that is, the state of the vehicle-mounted battery 12.

On the other hand, when the maximum power is supplied in this way, the input power needs to be adjusted on the power receiving device 30 side. For example, as shown in FIG. 3, it is conceivable that the booster circuit adjusts the output power (DC current) from the rectifier circuit 33 according to the required power of the vehicle-mounted battery 12. With this configuration, even if the output current from the rectifier circuit 33 is not a constant current, it is possible to appropriately adjust the current. However, in a contactless power feeding system that feeds a large amount of power, such as a vehicle, the inductor 10L of the booster circuit becomes large. As a result, there is a problem that the power receiving device 30 becomes large even though the accommodation space is limited.

Therefore, in the present embodiment, the power transmission side filter circuit 23, the power transmission side resonance circuit 24, the power reception side resonance circuit 31, and the power reception side resonance circuit 31 are arranged so that the input voltage to the power transmission side filter circuit 23 and the output current from the power reception side filter circuit 32 are proportional to each other. Each circuit of the power receiving side filter circuit 32 was configured.

Specifically, the power transmitting side filter circuit 23 and the power receiving side filter circuit 32 are immittance converters in which the input voltage and the output current are proportional and the input current and the output voltage are proportional. Further, in the power transmission side resonance circuit 24, the power transmission side resonance coils 24Lu, 24Lv, 24Lw are connected in series to the power transmission side resonance capacitors 24Cu, 24Cv, 24Cw. Then, in the power receiving side resonance circuit 31, the power receiving side resonance coils 31Lu, 31Lv, 31Lw were connected in series to the power receiving side resonance capacitors 31Cu, 31Cv, 31Cw. That is, the SS method was adopted.

As a result, the output voltage V1 from the inverter circuit 22 and the output current I2 of the rectifier circuit 33 are proportional to each other as shown in the equations (1) to (9). Therefore, if the output voltage from the inverter circuit 22 is constant, the output current of the rectifier circuit 33 can be made constant. Then, if the current is a constant current, the current is not interrupted, so that it is not necessary to provide an inductor between the rectifier circuit 33 and the diode 34. Therefore, the inductor can be omitted or downsized, and the power receiving device 30 can be downsized.

Further, the power reception control unit 70 calculates chargeable power based on the output current and output voltage of the power receiving device 30, and controls the switch unit 35 based on comparison with the required power of the vehicle-mounted battery 12. As a result, the output power can be adjusted (suppressed), and the in-vehicle battery 12 can be appropriately charged.

(Other embodiments)
The present disclosure is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present disclosure. In the following description, the same or equivalent parts in each embodiment are designated by the same reference numerals, and the description of the same reference portions is cited.

In the above embodiment, the three-phase power transmission side resonance coils 24Lu, 24Lv, 24Lw and the power reception side resonance coils 31Lu, 31Lv, 31Lw are provided, but the number of phases may be arbitrarily changed. For example, as shown in FIG. 5, the power transmission side resonance circuit 24 and the power reception side resonance circuit 31 may be single-phase. Alternatively, as shown in FIG. 6, the contactless power supply system 10 may be configured such that the power transmission side resonance circuit 24 has one phase and the power reception side resonance circuit 31 has two phases.

In the above-described embodiment, if the input voltage to the power transmission side filter circuit 23 and the output current from the power reception side filter circuit 32 are proportional, the power transmission side filter circuit 23, the power transmission side resonance circuit 24, the power reception side resonance circuit 31, and The configuration of each circuit of the power receiving side filter circuit 32 may be arbitrarily changed. For example, the contactless power feeding system 110 having a circuit configuration as shown in FIG. 7 may be used. In the power transmission device 120 of FIG. 7, the power transmission side filter circuit 123 is a transformer characteristic filter circuit in which the input voltage and the output voltage are proportional. In the power receiving device 130, the power receiving side filter circuit 132 is an immittance converter. In the power transmission side resonance circuit 124, the power transmission side resonance coil 24L is connected in series to the power transmission side resonance capacitor 24C. On the other hand, in the power receiving side resonance circuit 131, the power receiving side resonance coil 31L is connected in parallel to the power receiving side resonance capacitor 31C. In other words, it is the SP system of primary side series and secondary side parallel. Even in this case, the input voltage to the power transmitting side filter circuit 23 and the output current from the power receiving side filter circuit 32 can be made proportional.

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

In a contactless power supply system (10) for supplying power in a contactless manner between a power transmission device (20) provided on a road side and a power reception device (30) provided on a vehicle side to charge a storage battery provided in the vehicle,
The power transmission device,
An inverter (22) for converting a direct current input from a direct current power source into an alternating current,
A transmission-side filter circuit (23) that is connected to the inverter and removes an alternating current in a predetermined frequency range;
A power transmission side resonance coil (24Lu, 24Lv, 24Lw) and a power transmission side resonance capacitor (24Cu, 24Cv, 24Cw) connected to the power transmission side resonance coil, and a power transmission side resonance circuit (24),
The power receiving device,
A power receiving side resonance circuit (31) having a power receiving side resonance coil (31Lu, 31Lv, 31Lw) and a power receiving side resonance capacitor (31Cu, 31Cv, 31Cw) connected to the power receiving side resonance coil;
A power receiving side filter circuit (32) which is connected to the power receiving side resonance circuit and removes an alternating current in a predetermined frequency range;
A rectifier (33) that is connected to the power receiving side filter circuit and rectifies an alternating current into a direct current;
A diode (34) that is connected in series to the rectifier and that allows a current to flow from the rectifier to the output terminal (30a) of the power receiving device,
The power transmitting side filter circuit, the power transmitting side resonant circuit, the power receiving side resonant circuit, and the power receiving side filter circuit are arranged such that an input voltage to the power transmitting side filter circuit and an output current from the power receiving side filter circuit are proportional to each other. A contactless power supply system in which the circuit is configured.
A switch unit (35) for switching between energization and de-energization between the rectifier and the ground terminal,
A control unit (70) for controlling the switch unit,
The output voltage from the inverter is constant,
The non-contact according to claim 1, wherein the control unit calculates chargeable power based on an output current and an output voltage of the power receiving device, and controls the switch unit based on comparison with required power of the storage battery. Power supply system.
The power transmission side filter circuit and the power reception side filter circuit are immittance converters in which the input voltage and the output current are respectively proportional, and the input current and the output voltage are proportional,
In the power transmission side resonance circuit, the power transmission side resonance coil, while the power transmission side resonance capacitor is connected in series,
The contactless power feeding system according to claim 1, wherein, in the power receiving side resonance circuit, the power receiving side resonance coil is connected in series with the power receiving side resonance capacitor.
The power transmission side filter circuit is an immittance converter in which the input voltage and the output current are proportional, and the input current and the output voltage are proportional,
The power receiving side filter circuit is a transformer characteristic filter circuit in which an input voltage and an output voltage are proportional,
In the power transmission side resonance circuit, the power transmission side resonance coil, while the power transmission side resonance capacitor is connected in series,
The contactless power feeding system according to claim 1, wherein, in the power receiving side resonance circuit, the power receiving side resonance coil is connected in parallel with the power receiving side resonance capacitor.