Contactless Power Transmission System

Abstract

To provide a non-contact power transmission system capable of inhibiting output reduction and loss increase from being caused by temperature fluctuation on the power reception side.SOLUTION: A non-contact power transmission system 1 comprises a power reception device 4 and a controller 17. The power reception device 4 receives AC power transmitted in a non-contact manner from a power transmission device 2. The controller 17 comprises a coil temperature detection unit, a magnetic member temperature detection unit, and a capacitor temperature detection unit that acquires respective temperatures of a secondary side coil, a magnetic member, and a secondary side capacitor of the power reception device 4. The controller 17 comprises a request frequency correction unit that corrects a request frequency of power transmission by the power transmission device 2 on the basis of the respective temperatures of the secondary side coil, the magnetic member, and the secondary side capacitor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a contactless power transfer system. [Background technology]

[0002] In recent years, research and development has been conducted into charging vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy. Conventionally, in a contactless power transfer system that supplies power from outside the vehicle to the vehicle by contactless power transfer, a device is known that controls the switching frequency of an inverter circuit of a power transmitting device so as to maximize the power supply efficiency to the power receiving device depending on the temperatures of elements such as coils and capacitors that constitute the power transmitting device and the power receiving device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 196239 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, in technology related to charging and supplying power to a vehicle equipped with a secondary battery, it is desired to suppress the output reduction and loss increase associated with the fluctuation of the eigenvalue (frequency) of a resonant circuit formed by a coil and a capacitor on the power receiving side. For example, in the above-mentioned conventional non-contact power transmission system, the eigenvalue (frequency) of the resonant circuit may fluctuate not only due to the decrease in inductance associated with a temperature rise of the coil and the change in capacitance associated with a temperature change of the capacitor, but also due to the temperature change of other parts of the power receiving device. For example, if the eigenvalue (frequency) of the resonant circuit fluctuates due to the temperature change of a part cooled by the wind (wind while traveling, etc.) received while the mobile body is moving, the output reduction and loss increase may occur.

[0005] The present invention aims to provide a contactless power transfer system capable of suppressing a decrease in output and an increase in loss caused by temperature fluctuations on the power receiving side, thereby contributing to energy efficiency. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A contactless power transfer system according to one aspect of the present invention (e.g., contactless power transfer system 1 in the embodiment) includes a coil (e.g., secondary coil 15a in the embodiment) that receives AC power transferred in a contactless manner from a power transmission side coil (e.g., primary coil 8a in the embodiment) of a power transmission device (e.g., power transmission device 2 in the embodiment), a power receiving unit (e.g., power receiving unit 15 in the embodiment) having a resonance capacitor (e.g., secondary capacitor 15c in the embodiment) connected in series with the coil and a magnetic member (e.g., core member 19 in the embodiment) provided for the coil, and a power conversion unit (e.g., power receiving unit 2 in the embodiment) that converts the AC power received by the power receiving unit into DC power. The power transmission device includes a power conversion unit 16) and a control device (for example, control device 17 in the embodiment) that controls the operation of the power conversion unit. The control device includes a temperature acquisition unit (for example, a coil temperature detection unit 31, a magnetic member temperature detection unit 32, and a capacitor temperature detection unit 33 in the embodiment) that acquires temperatures of the coil, the capacitor, and the magnetic member, and a correction unit (for example, an inductance correction unit 34, a resistance value correction unit 35, a mutual inductance correction unit 36, a capacitance correction unit 37, a maximum efficiency point calculation unit 38, a difference calculation unit 39, and a required frequency correction unit 40 in the embodiment) that corrects a required frequency of power transmission by the power transmission device based on the temperatures acquired by the temperature acquisition unit. The correction unit corrects at least any one of a self-inductance of the coil, a resistance value of the power receiving unit, a capacitance of the capacitor, and a mutual inductance between the power transmitting coil and the coil, based on each of the temperatures. .

[0007] (2): In the contactless power transfer system described in (1) above, the correction unit may correct the self-inductance of the coil, the resistance value of the power receiving unit, the capacitance of the capacitor, and the mutual inductance between the power transmitting coil and the coil based on each of the temperatures.

[0008] (3): The contactless power transfer system described in (2) above may include a power storage device (e.g., power storage device 11 in the embodiment) connected to the power conversion unit, and the correction unit may correct the required frequency, which is set based on the required power according to the remaining capacity of the power storage device. Effect of the Invention

[0009] According to (1) above, the control device can suppress a decrease in output and an increase in loss in power transmission caused by temperature fluctuations on the power receiving side by correcting the required frequency of power transmission by the power transmitting device based on the temperatures of the coil, capacitor, and magnetic components of the power receiving unit.

[0010] In the above case (2), the control device corrects the self-inductance of the coil of the power receiving unit, the resistance value of the power receiving unit, the capacitance of the capacitor of the power receiving unit, and the mutual inductance, thereby being able to suppress output reduction and increased loss by correcting the required frequency even if the eigenvalue (frequency) of the resonant circuit fluctuates due to, for example, temperature changes in the power receiving unit.

[0011] In the above case (3), the control device corrects the required frequency, which is set based on the required power corresponding to the remaining capacity of the storage device, thereby suppressing an increase in the charging and discharging of the storage device associated with power transmission from the power transmission device and power consumption by the mobile body, while suppressing a decrease in output and an increase in losses in the power transmission. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a configuration of a contactless power transmission system according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a diagram showing details of the configuration of a contactless power transfer system according to an embodiment of the present invention. [Diagram 3] 1 is a diagram showing the configuration of a power transmitting unit and a power receiving unit in a contactless power transfer system according to an embodiment of the present invention. [Figure 4] FIG. 2 is an exploded perspective view showing a configuration of a coil unit of a power receiving unit in the contactless power transfer system according to the embodiment of the present invention. [Diagram 5] FIG. 2 is a block diagram showing a first functional configuration of a control device in the contactless power transfer system according to the embodiment of the present invention. [Figure 6] FIG. 4 is a block diagram showing a second functional configuration of the control device in the contactless power transfer system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a contactless power transfer system according to an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 and Fig. 2 are diagrams showing the configuration of a contactless power transfer system 1 according to an embodiment. Fig. 3 is a diagram showing the configurations of a power transmitting unit 8 and a power receiving unit 15 of the contactless power transfer system 1 according to an embodiment. Fig. 4 is an exploded perspective view showing the configuration of a coil unit 18 of the power receiving unit 15 in the contactless power transfer system 1 according to an embodiment. A contactless power transfer system 1 according to the embodiment supplies power to a moving body such as a vehicle from outside the moving body by contactless power transfer. The vehicle is, for example, an electrically-driven vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0014] (Non-contact power transmission system) 1 and 2, a contactless power transfer system 1 according to an embodiment includes, for example, a power transmitting device 2 installed on a vehicle's running path or the like, and a drive control device 3 and a power receiving device 4 mounted on a moving body such as a vehicle. Note that the contactless power transfer system 1 according to an embodiment may include at least only components mounted on the moving body (for example, the drive control device 3 and the power receiving device 4), or contactless power transfer may be performed by combining components external to the moving body (for example, the power transmitting device 2) with the contactless power transfer system 1 mounted on the moving body.

[0015] The power transmission device 2 includes, for example, a power supply unit 6, a power transmission power conversion unit 7, and a power transmission unit 8. Note that the power transmission device 2 may include at least a plurality of power transmission units 8 in a predetermined power transmission section on a road on which the vehicle runs, for example. The power supply unit 6 includes, for example, an AC power supply such as a commercial power supply, an AC-DC converter that converts the AC power into DC power, and a power smoothing capacitor. The power supply unit 6 converts the AC power supplied from the AC power supply into DC power by the AC-DC converter.

[0016] The transmission power conversion unit 7 includes, for example, an inverter that converts DC power into AC power. The inverter of the transmission power conversion unit 7 includes, for example, a bridge circuit formed by a plurality of switching elements and rectifying elements that are bridge-connected in two phases, and a voltage smoothing capacitor. Each switching element is, for example, a transistor such as a SiC (Silicon Carbide) MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The multiple switching elements are high-side arm and low-side arm transistors 7a and 7b that form a pair in each phase. The rectifying element is, for example, a free wheel diode connected in parallel to each of the transistors 7a and 7b. A voltage smoothing capacitor 7c is connected in parallel to the bridge circuit.

[0017] The power transmitting unit 8 transmits power by changing a high-frequency magnetic field, for example, by magnetic field coupling such as magnetic resonance or electromagnetic induction. As shown in Fig. 3, the power transmitting unit 8 includes a resonant circuit formed by a primary coil 8a, a primary resistor 8b, and a primary capacitor 8c connected in series. The power transmitting unit 8 includes a sensor such as a current sensor that detects a current It flowing through the resonant circuit.

[0018] For example, the power transmission device 2 transmits power to the power receiving device 4 of the vehicle by controlling the on (conducting) and off (cutting) switching of each switching element of the transmission power conversion unit 7 in accordance with a preset drive frequency or information on a required frequency received from the power receiving device 4.

[0019] 1 and 2, a drive control device 3 of a moving body such as a vehicle includes, for example, a power storage device 11, a power storage voltage converter 12, a power converter 13, and a rotating electric machine 14. A power receiving device 4 of the moving body includes, for example, a power receiving unit 15 and a power receiving power converter 16. The drive control device 3 and the power receiving device 4 include, for example, a common control device 17. For example, in the case of an electric vehicle or the like that is driven using the power storage device 11 as a power source, the drive control device 3 does not need to include the storage voltage conversion unit 12. For example, in the case of a hybrid vehicle or the like that is driven using the power storage device 11 and an internal combustion engine as a power source, the drive control device 3 may include the storage voltage conversion unit 12.

[0020] The power storage device 11 is connected to a storage voltage converter 12. The power storage device 11 is charged by electric power transmitted in a non-contact manner from a power transmission device 2 outside the vehicle. The power storage device 11 exchanges electric power with a rotating electric machine 14 via the storage voltage converter 12 and a power converter 13. The power storage device 11 includes a battery, such as a lithium ion battery, a current sensor that detects the current of the battery, and a voltage sensor that detects the voltage of the battery. For example, in an electric vehicle or the like that does not include the storage voltage conversion unit 12, the power storage device 11 is connected to the power conversion unit 13 and the received power conversion unit 16, which will be described later.

[0021] The storage voltage conversion unit 12 is connected to the power conversion unit 13 and the received power conversion unit 16. The storage voltage conversion unit 12 includes, for example, a voltage controller that performs bidirectional voltage conversion of step-up and step-down. The voltage controller converts input power and output power by bidirectional voltage conversion when charging and discharging the power storage device 11. The voltage controller of the storage voltage conversion unit 12 includes, for example, a pair of first reactors, a first element module, and a capacitor for voltage smoothing.

[0022] The pair of first reactors 12a, 12a are magnetically coupled to each other with opposite polarity to form a composite reactor. The pair of first reactors 12a, 12a are connected to a connection point between the high-side arm and the low-side arm of each phase of the first element module. The first element module includes a first bridge circuit formed by a plurality of switching elements and rectifier elements that are bridge-connected in, for example, two phases. Each switching element is, for example, a transistor such as a SiC MOSFET. The plurality of switching elements are high-side arm and low-side arm transistors 12b, 12c that form a pair in each phase. The rectifier element is, for example, a freewheeling diode connected in parallel to each of the transistors 12b, 12c. A voltage smoothing capacitor 12d is connected in parallel to the power storage device 11. The storage voltage converter 12 includes a resistor 12e and a transistor 12f connected in series to each other. The resistor 12e and the transistor 12f are connected in parallel to a first bridge circuit.

[0023] The pair of first reactors 12a and the first element module of the voltage controller perform voltage conversion by so-called two-phase interleaving. In the two-phase interleaving, one cycle of switching control of the first-phase transistors 12b and 12c and one cycle of switching control of the second-phase transistors 12b and 12c among the two-phase transistors 12b and 12c connected to the pair of first reactors 12a are shifted from each other by half a cycle.

[0024] The power conversion unit 13 is connected to a rotating electric machine 14. The power conversion unit 13 includes, for example, a power converter that converts between DC power and AC power. The power converter includes, for example, a second element module and a voltage smoothing capacitor. The second element module includes, for example, a second bridge circuit formed by a plurality of switching elements and rectifier elements bridge-connected in three phases. Each switching element is, for example, a transistor such as a SiC MOSFET. The plurality of switching elements are high-side arm and low-side arm transistors 13a and 13b that form a pair in each phase. The rectifier elements are, for example, freewheeling diodes connected in parallel to each of the transistors 13a and 13b. A voltage smoothing capacitor 13c is connected in parallel to the second bridge circuit.

[0025] The second element module controls the operation of the rotating electric machine 14 by receiving and transmitting electric power. For example, when the rotating electric machine 14 is powered, the second element module converts DC power input from the positive and negative DC terminals 13p, 13n into three-phase AC power and supplies the three-phase AC power from the three-phase AC terminals 13d to the rotating electric machine 14. The second element module generates a rotational driving force by sequentially commutating the current to the three-phase stator windings of the rotating electric machine 14. For example, during regeneration of the rotating electric machine 14, the second element module converts three-phase AC power input from the three-phase stator windings into DC power by driving the switching elements of each phase to be on (conductive) and off (disconnected) in synchronization with the rotation of the rotating electric machine 14. The second element module can supply the DC power converted from the three-phase AC power to the power storage device 11 via the storage voltage converter 12.

[0026] The rotating electric machine 14 is, for example, a three-phase AC brushless DC motor provided for driving a vehicle. The rotating electric machine 14 includes a rotor having a permanent magnet for a field, and a stator having a three-phase stator winding that generates a rotating magnetic field that rotates the rotor. The three-phase stator winding is connected to three-phase AC terminals 13d of the power conversion unit 13. The rotating electric machine 14 generates a rotational driving force by performing a power running operation using the electric power supplied from the electric power conversion unit 13. For example, if the rotating electric machine 14 can be connected to the wheels of a vehicle, the rotating electric machine 14 generates a driving force for traveling by performing a power running operation using the electric power supplied from the electric power conversion unit 13. The rotating electric machine 14 may generate electric power by performing a regenerative operation using rotational power input from the wheel side of the vehicle. If the rotating electric machine 14 can be connected to an internal combustion engine of the vehicle, the rotating electric machine 14 may generate electric power using the power of the internal combustion engine.

[0027] The power receiving unit 15 is connected to the receiving power conversion unit 16. The power receiving unit 15 receives power by a change in a high-frequency magnetic field transmitted from the power transmitting unit 8, for example, by magnetic field coupling such as magnetic resonance or electromagnetic induction. As shown in Fig. 3, the power receiving unit 15 includes a resonant circuit formed by, for example, a secondary side coil 15a, a secondary side resistor 15b, and a secondary side capacitor 15c connected in series. The power receiving unit 15 includes a sensor such as a current sensor that detects a current Ir flowing through the resonant circuit.

[0028] As shown in FIG. 4, the coil unit 18 constituting a part of the power receiving unit 15 includes a secondary coil 15a, an insulating member 18a, a ferrite core 18b, and a core member 19, for example.

[0029] The secondary coil 15a has an outer shape that is, for example, spirally wound around a central axis. The insulating member 18a has an outer shape, for example, a rectangular sheet shape with through holes formed in the thickness direction. The insulating member 18a is made of an electrically insulating material. The ferrite core 18b has an outer shape, for example, of a rectangular plate with a through hole formed in the thickness direction.

[0030] The core member 19 includes, for example, a plate-shaped portion 19a, a wall portion 19b, and a cover portion 19c. The core member 19 is made of a magnetic material, for example, an electromagnetic steel plate such as a silicon steel plate. The plate-like portion 19a has an outer shape, for example, of a rectangular frame having a through hole penetrating the center in the thickness direction. The outer shape of the wall portion 19b is, for example, a rectangular frame shape that protrudes in a direction along the central axis from a peripheral portion surrounding the through hole of the plate-like portion 19a. The wall portion 19b is disposed in the air-core region of the secondary coil 15a and in each of the through holes of the insulating member 18a and the ferrite core 18b. The cover portion 19c has an outer shape, for example, a rectangular plate shape, and closes the open end of the wall portion 19b in the protruding direction.

[0031] The insulating member 18a, the ferrite core 18b, and the plate-shaped portion 19a of the core member 19 are disposed, for example, on the rear side of the secondary coil 15a when viewed from the primary coil 8a facing the secondary coil 15a. The secondary coil 15a, the insulating member 18a, the ferrite core 18b, and the plate-shaped portion 19a are disposed so as to be stacked in order in the direction along the central axis.

[0032] The capacitance of the secondary-side capacitor 15c of the power receiving unit 15 is set, for example, according to the higher-frequency resonance point of the two resonance points in the frequency characteristics of the impedance of the resonant circuit of the power receiving unit 15. For example, a resonance point where the impedance is minimal on the low-frequency side indicates an in-phase resonance mode (low-frequency mode), and a resonance point where the impedance is minimal on the high-frequency side indicates an anti-phase resonance mode (high-frequency mode). An anti-resonance point where the impedance is maximized between the two resonance points indicates switching between the in-phase resonance mode and the anti-phase resonance mode. For example, the capacitance of the secondary-side capacitor 15c, which is set during manufacture, is set according to the frequency of the high-frequency mode so that the resonance point is matched to the frequency of the high-frequency mode at a specified room temperature.

[0033] 1 and 2 is connected to the power conversion unit 13. The receiving power conversion unit 16 includes a so-called full-bridgeless (or bridgeless and totem-pole) power factor correction (PFC) circuit that converts AC power into DC power. The so-called bridgeless PFC is a PFC that does not include a bridge rectifier made of multiple bridge-connected diodes, and the so-called totem-pole PFC is a PFC that includes a pair of switching elements of the same conductivity type that are connected in series in the same direction (totem-pole connection).

[0034] The receiving power conversion unit 16 includes, for example, a third bridge circuit formed by a plurality of switching elements and rectifying elements bridge-connected in two phases, and a voltage smoothing capacitor. Each switching element is, for example, a transistor such as a SiC MOSFET. The plurality of switching elements are high-side arm and low-side arm transistors 16a, 16b that form a pair in each phase. The rectifying element is, for example, a free wheel diode connected in parallel to each of the transistors 16a, 16b. The voltage smoothing capacitor 16c is connected in parallel to the third bridge circuit.

[0035] For example, a power receiving device 4 equipped with a power receiving unit 15 and a power receiving power conversion unit 16 receives power transmitted from the power transmitting device 2 by controlling the on (conducting) and off (cutting) switching of each switching element of the power receiving power conversion unit 16 in accordance with information on the frequency of power transmission by the power transmitting device 2.

[0036] The control device 17 comprehensively controls, for example, the drive control device 3 and the power receiving device 4 of a moving body such as a vehicle. The control device 17 is a software function unit that functions by a processor such as a CPU (Central Processing Unit) executing a predetermined program. The software function unit is an ECU that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the control device 17 may be an integrated circuit such as an LSI (Large Scale Integration).

[0037] The control device 17 generates, for example, control signals indicating the timing for driving each switching element on (conducting) and off (cutting), and generates gate signals for actually driving each switching element on and off based on the control signals. For example, the control device 17 controls the switching of each switching element of the power receiving device 4 to rectify the AC power received from the power transmitting device 2 into DC power, while improving the power factors of the input voltage and the input current.

[0038] For example, the control device 17 controls the output according to the target output by a synchronous rectification operation that synchronously drives a plurality of switching elements of the power receiving device 4 to be turned on and off, and a short-circuit operation that short-circuits the secondary coil 15a. For example, the control device 17 controls the synchronous rectification operation according to the magnitude and phase of a current generated in the power receiving unit 15 by the power transmitted from the power transmitting device 2, i.e., a current Ir flowing through the secondary coil 15a. The control device 17 controls the multiple switching elements of the power receiving power conversion unit 16 by soft switching of so-called zero voltage switching (ZVS). In zero voltage switching (ZVS), each switching element is turned on (switched from an off state to an on state) after the voltage across both ends is made zero by discharging the output capacitance (parasitic capacitance) in the off state during the dead time period of each phase. For example, the control device 17 controls the short-circuit operation by continuing the zero voltage switching (ZVS) synchronous rectification operation in the high side arm of each phase of the receiving power conversion unit 16 while turning on only the low side arm of each phase.

[0039] For example, the control device 17 sets a frequency required for the power transmission by the power transmitting device 2 (required frequency) in accordance with the remaining capacity (SOC: State Of Charge) of the power storage device 11. FIG. 5 is a block diagram showing a first functional configuration of the control device 17 in the contactless power transfer system 1 of the embodiment. As shown in FIG. 5, the control device 17 includes, for example, a drive required power calculation unit 21, an auxiliary power consumption calculation unit 22, an estimated power loss calculation unit 23, an adder 24, a required assist power calculation unit 25, a subtractor 26, and a required frequency acquisition unit 27.

[0040] The drive power requirement calculation unit 21 calculates, for example, power (drive power requirement) required to be supplied from the power conversion unit 13 to the rotating electric machine 14 according to a target drive force of the mobile body or the rotating electric machine 14. The target drive force is calculated, for example, based on outputs of various sensors related to the moving state of the mobile body or the state of the rotating electric machine 14. The various sensors include, for example, a speed sensor that detects the speed of the vehicle and an accelerator position sensor that detects the accelerator operation amount, as well as a current sensor, a voltage sensor, a temperature sensor, and the like for grasping the state of the rotating electric machine 14.

[0041] The auxiliary equipment power consumption calculation unit 22 calculates the power consumption (auxiliary equipment power consumption) of various auxiliary equipment connected to the power storage device 11 based on, for example, the outputs of various sensors. The various sensors are, for example, a current sensor, a voltage sensor, a temperature sensor, etc. for grasping the state of the power storage device 11 and the power consumption of the various auxiliary equipment, etc. The various auxiliary equipment are, for example, a power converter, an air conditioner, various pumps, etc. The estimated power loss calculation unit 23 calculates, for example, the estimated power loss in the storage voltage conversion unit 12 and the received power conversion unit 16.

[0042] The adder 24 calculates the power required by the system (required system power) by adding the drive required power input from the drive required power calculation unit 21, the auxiliary power consumption input from the auxiliary power consumption calculation unit 22, and the power loss input from the estimated power loss calculation unit 23. The required assist power calculation unit 25 calculates power (required assist power) according to the remaining capacity (SOC: State Of Charge) required based on, for example, ensuring a desired output of the power storage device 11. The subtraction unit 26 calculates the requested power, which is a target for the power that the power receiving device 4 receives from the power transmitting device 2, by subtracting the requested assist power input from the requested assist power calculation unit 25 from the requested system power input from the addition unit 24.

[0043] The required frequency acquisition unit 27 calculates a frequency required for the power transmission of the power transmitting device 2 (required frequency) according to the required power input from the subtraction unit . The required frequency acquisition unit 27 acquires a required frequency corresponding to the required power based on data on the correspondence between the frequency and output of power transmission, which exhibits different characteristics depending on the combination of magnetic materials, coils, etc. in each of the power transmitting unit 8 of the power transmitting device 2 and the power receiving unit 15 of the power receiving device 4.

[0044] For example, the control device 17 corrects the required frequency based on the temperatures of the elements constituting the power receiving unit 15 and the magnetic members constituting the coil unit 18. FIG. 6 is a block diagram showing a second functional configuration of the control device 17 in the contactless power transfer system 1 of the embodiment. As shown in FIG. 6, the control device 17 includes, for example, a coil temperature detection unit 31, a magnetic component temperature detection unit 32, a capacitor temperature detection unit 33, an inductance correction unit 34, a resistance value correction unit 35, a mutual inductance correction unit 36, a capacitance correction unit 37, a maximum efficiency point calculation unit 38, a difference calculation unit 39, and a required frequency correction unit 40.

[0045] The coil temperature detection unit 31 includes a temperature sensor that detects the temperature of the secondary coil 15a, and outputs a signal representing the detected temperature value. The magnetic member temperature detection unit 32 includes a temperature sensor that detects the temperature of a magnetic member such as the plate-like portion 19a of the core member 19, and outputs a signal representing the detected temperature value. The capacitor temperature detection unit 33 includes a temperature sensor that detects the temperature of the secondary-side capacitor 15c, and outputs a signal of the detected temperature value.

[0046] The inductance correction unit 34 corrects the self-inductance Lr of the secondary coil 15a according to the detected temperature value of the secondary coil 15a output from the coil temperature detection unit 31, with reference to preset correction data. The resistance value correction unit 35 corrects the resistance value Rr of the resonant circuit of the power receiving unit 15 according to the detection value of the temperature of the secondary coil 15a output from the coil temperature detection unit 31, with reference to preset correction data. The mutual inductance correction unit 36 ​​corrects the mutual inductance Lm between the primary coil 8a and the secondary coil 15a by referring to preset correction data in accordance with the detection value of the temperature of the magnetic member output from the magnetic member temperature detection unit 32. The capacitance correction unit 37 corrects the capacitance Cr of the secondary capacitor 15c in accordance with the detected value of the temperature of the secondary capacitor 15c output from the capacitor temperature detection unit 33, with reference to preset correction data.

[0047] The maximum efficiency point calculation unit 38 calculates the frequency ω at the maximum efficiency point where the efficiency η of power transmission between the primary coil 8a and the secondary coil 15a is maximized, based on the self-inductance Lr, resistance value Rr, mutual inductance Lm, and capacitance Cr corrected by each correction unit 34, 35, 36, and 37. For example, as shown in the following formula (1), the efficiency η of power transmission is described by the frequency ω of power transmission, the mutual inductance Lm, the load resistance value (resistance value on the load side as seen from the power transmitting unit 8 and the power receiving unit 15) R, the resistance value Rr, the self-inductance Lr, the capacitance Cr, and the resistance value Rt of the resonant circuit of the power transmitting unit 8.

[0048]

number

[0049] The difference calculation unit 39 calculates the difference between the required frequency output from the required frequency acquisition unit 27 and the frequency ω at the maximum efficiency point output from the maximum efficiency point calculation unit . The required frequency correction unit 40 corrects the required frequency in accordance with the difference in frequency output from the difference calculation unit 39 .

[0050] The control device 17 transmits to the power transmitting device 2 the required frequency calculated and corrected at each timing before the mobile body arrives at each power transmission section of the power transmitting device 2, for example, by appropriate communication between the power transmitting device 2 and the mobile body. The communication between the power transmitting device 2 and the mobile body is, for example, communication by induced voltage between the coils 8a, 15a of the power transmitting device 2 and the power receiving device 4, or wireless communication by a communication device additionally provided in each of the power transmitting device 2 and the mobile body.

[0051] As described above, according to the embodiment of the contactless power transfer system 1, the control device 17 corrects the required frequency of power transfer by the power transmitting device 2 based on the temperatures of the secondary coil 15a, the core member 19, and the secondary capacitor 15c, thereby suppressing a decrease in output and an increase in loss in power transfer caused by temperature fluctuations on the power receiving side. By correcting the self-inductance Lr of the secondary coil 15a, the resistance value Rr of the power receiving unit 15, the capacitance Cr of the secondary capacitor 15c, and the mutual inductance Lm, the control device 17 can suppress output reduction and loss increase by correcting the required frequency, even if the eigenvalue (frequency) of the resonant circuit fluctuates due to, for example, temperature changes in the power receiving unit 15.

[0052] By correcting the required frequency, which is set based on the required power corresponding to the remaining capacity (SOC) of the storage device 11, the control device can suppress an increase in charging and discharging of the storage device 11 associated with power transmission from the power transmission device 2 and power consumption by the mobile body, while suppressing a decrease in power transmission output and an increase in loss.

[0053] (Modification) Modifications of the embodiment will be described below. Note that the same parts as those in the above-described embodiment will be denoted by the same reference numerals and descriptions thereof will be omitted or simplified. In the above-described embodiment, the control device 17 is provided with each of the temperature detection units 31, 32, and 33, but is not limited thereto. For example, instead of each of the temperature detection units 31, 32, and 33, the control device 17 may calculate the temperature of each part by a temperature estimation process based on the thermal resistance at each part of the power receiving unit 15, the ambient temperature of the power receiving unit, and cooling caused by wind (wind caused by traveling, etc.) received while the mobile object is moving.

[0054] In the above-described embodiment, the contactless power transfer system 1 includes the storage voltage converter 12 that converts the input and output power of the power storage device 11. However, the present invention is not limited to this, and the storage voltage converter 12 may be omitted. For example, in the case of a hybrid vehicle that is powered by an electric storage device 11 and an internal combustion engine, the drive control device 3 is provided with a storage voltage conversion unit 12, whereas in the case of an electric vehicle that is powered by an electric storage device 11, the drive control device 3 does not need to be provided with the storage voltage conversion unit 12.

[0055] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as the scope and spirit of the invention. [Explanation of symbols]

[0056] Reference Signs List 1... non-contact power transmission system, 2... power transmission device, 3... drive control device, 4... power receiving device, 6... power supply unit, 7... power transmission power conversion unit, 8... power transmission unit, 8a... primary side coil (power transmission side coil), 11... power storage device, 12... power storage voltage conversion unit, 13... power conversion unit, 14... rotating electric machine, 15... power receiving unit, 15a... secondary side coil (coil), 15c... secondary side capacitor (capacitor), 16... power receiving power conversion unit (power conversion unit), 17... control device, 27... required frequency Wave number acquisition unit, 31... coil temperature detection unit (temperature acquisition unit), 32... magnetic material temperature detection unit (temperature acquisition unit), 33... capacitor temperature detection unit (temperature acquisition unit), 34... inductance correction unit (correction unit), 35... resistance value correction unit (correction unit), 36... mutual inductance correction unit (correction unit), 37... capacitance correction unit (correction unit), 38... maximum efficiency point calculation unit (correction unit), 39... difference calculation unit (correction unit), 40... required frequency correction unit (correction unit).

Claims

1. a coil for receiving AC power transmitted in a non-contact manner from a power transmitting coil of a power transmitting device; A resonance capacitor connected in series to the coil; a magnetic member provided for the coil; A power receiving unit having a power conversion unit that converts the AC power received by the power receiving unit into DC power; A control device for controlling an operation of the power conversion unit; Equipped with The control device includes: a temperature acquisition unit that acquires temperatures of the coil, the capacitor, and the magnetic member; a correction unit that corrects a required frequency of power transmission by the power transmitting device based on the temperatures acquired by the temperature acquisition unit; Equipped with The correction unit is Based on the temperatures, at least one of the self-inductance of the coil, the resistance value of the power receiving unit, the capacitance of the capacitor, and the mutual inductance between the power transmitting coil and the coil is corrected. Contactless power transmission system.

2. The correction unit is Based on the temperatures, the self-inductance of the coil, the resistance value of the power receiving unit, the capacitance of the capacitor, and the mutual inductance between the power transmitting coil and the coil are corrected. The contactless power transfer system according to claim 1 .

3. a power storage device connected to the power conversion unit, The correction unit is The required frequency is corrected based on the required power according to the remaining capacity of the power storage device. The contactless power transfer system according to claim 2 .

Images