JP2016086577A - Non-contact power transmission/reception system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more properly determine a distance between a power transmission coil of a transmission apparatus and a power reception coil of a reception apparatus while suppressing an increase in the number of components.SOLUTION: A non-contact power transmission apparatus estimates a distance Lv in the vehicle height direction between a power transmission coil 134 and a power reception coil 34 according to a vehicle height Hv from a vehicle height sensor as well as a distance Lh in the plane direction between the power transmission coil 134 and the power reception coil 34 using a coupling coefficient k obtained based on an output impedance Zs of a high-frequency power supply circuit 140 and calculates a distance L between the power transmission coil 134 and the power reception coil 34 on the basis of the estimated distance Lv in the vehicle height direction and the distance Lh in the plane direction, and can more exactly obtain a distance L between the power transmission coil 134 and the power reception coil 34 without increasing the number of other components only by mounting the vehicle height sensor.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a non-contact power transmission / reception system, and more particularly to a non-contact power transmission / reception system including a power transmission device having a power transmission coil, a power reception device having a power reception coil, and a vehicle equipped with a battery.

  Conventionally, as this type of non-contact power transmission / reception system, a system including a charging stand for detecting a mounting position on a top surface plate of a battery built-in device mounted on a top surface plate using a plurality of position detection coils has been proposed. (For example, refer to Patent Document 1). This charging stand includes a power supply coil that induces electric power to an induction coil in the battery built-in device, and a moving mechanism that moves the power supply coil. Then, when the battery built-in device is placed on the face plate, the position of the battery built-in device is detected by a plurality of position detection coils, and the power coil is moved to the detected placement position, and the battery in the battery built-in device is moved. To charge.

JP 2009-247194 A

  However, in the non-contact power transmission / reception system described above, it is necessary to incorporate a plurality of position detection coils in the charging stand in order to accurately detect the placement position of the battery built-in device. For this reason, the number of parts which comprise a charging stand increases, and an apparatus will become complicated. In addition, a moving mechanism for moving the power supply coil is required, which further complicates the apparatus and increases the size.

  The non-contact power transmission / reception system of the present invention is mainly intended to more appropriately obtain the inter-coil distance between the power transmission coil of the power transmission device and the power reception coil of the power reception device while suppressing an increase in the number of components.

  The non-contact power transmission / reception system of the present invention employs the following means in order to achieve the main object described above.

The non-contact power transmission and reception system of the present invention is
A power transmission device having a power transmission coil;
A vehicle having a battery and a power receiving device capable of receiving power from the power transmission device in a non-contact manner using a power receiving coil and charging the battery; and
A non-contact power transmission and reception system comprising:
A vehicle height sensor for detecting the vehicle height;
When power is transmitted from the power transmission device to the power reception device, the output impedance is calculated, and the distance between the power transmission coil and the power reception coil is calculated based on the output impedance and the vehicle height. Means for controlling the transmission of power,
It is characterized by providing.

  In the non-contact power transmission / reception system of the present invention, when transmitting power from the power transmission device to the power reception device, the output impedance is calculated, and the distance between the coil of the power transmission coil and the power reception coil is calculated based on the output impedance and the vehicle height. Since the output impedance can be approximately expressed as a function of the coupling coefficient, the coupling coefficient can be obtained from the output impedance, and the horizontal distance between the power transmission coil and the power receiving coil can be obtained from the coupling coefficient. Therefore, the distance between the coils can be obtained from the distance in the vertical direction between the power transmission coil and the power reception coil estimated from the vehicle height and the distance in the horizontal direction between the power transmission coil and the power reception coil estimated from the output impedance. Only by having a vehicle height sensor for detecting the vehicle height, the distance between the coil of the power transmission coil and the power reception coil can be obtained more appropriately without increasing the number of components in the power transmission device. Here, the control means may be included in the power transmission device or may be included in the power reception device. When the power receiving device includes the control means, power transmission can be controlled using the inter-coil distance by transmitting a control signal based on the inter-coil distance or the inter-coil distance to the power transmitting device. The inter-coil distance thus obtained is used for power transmission control. In this case, the power transmission to the power receiving apparatus can be controlled so that the power that can be transmitted increases as the distance between the coils decreases. As a result, power can be transmitted and received efficiently.

  The present invention is a power transmission device that has a power transmission coil and transmits power to the power reception device in a non-contact manner via a power reception coil included in a power reception device mounted on a vehicle, and transmits power from the power transmission device to the power reception device. At the time, the output impedance is calculated, the distance between the power transmission coil and the power receiving coil is calculated based on the output impedance and the vehicle height, and power transmission is controlled using the distance between the coils. It can also be set as the aspect of the power transmission apparatus.

  Further, the present invention is a vehicle-mounted power receiving device that receives power transmitted from a power transmitting device via a power transmitting coil in a contactless manner via a power receiving coil, and when receiving power from the power transmitting device, The output impedance of the power transmission device is calculated, the distance between the power transmission coil and the power receiving coil is calculated based on the output impedance and the vehicle height, and the power transmission from the power transmission device is controlled using the distance between the coils. It is also possible to adopt a mode of a power receiving device characterized by the above.

It is a block diagram which shows the outline of a structure of the non-contact power transmission / reception system 10 as one Example of this invention. It is a block diagram which shows the outline of a structure of the non-contact power transmission / reception system 10 as one Example of this invention. It is a flowchart which shows an example of the power transmission start time process performed by power transmission ECU170 at the time of the power transmission start. It is explanatory drawing which shows typically the method of calculating | requiring the distance L of the coil 134 for power transmission, and the coil 34 for power reception. It is explanatory drawing which shows an example of the power transmission possible electric power map.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 and FIG. 2 are configuration diagrams showing an outline of the configuration of a non-contact power transmission / reception system 10 as an embodiment of the present invention. As shown in FIGS. 1 and 2, the non-contact power transmission / reception system 10 according to the embodiment receives power from the power transmission device 130 installed in a parking lot or the like, the battery 26 and the power transmission device 130 and charges the battery 26. And an automobile 20 on which the power receiving device 30 is mounted.

   The power transmission device 130 includes a power transmission unit 131 connected to an AC power source 190 such as a household power source (for example, 200 V, 50 Hz), and a power transmission electronic control unit (hereinafter referred to as “power transmission ECU”) 170 that controls the power transmission unit 131. And a communication unit 180 that communicates with the power transmission ECU 170 and wirelessly communicates with a communication unit 80 (described later) of the automobile 20.

  The power transmission unit 131 includes a power transmission resonance circuit 132 and a high-frequency power circuit 140 provided between the AC power supply 190 and the power transmission resonance circuit 132. Here, the power transmission resonance circuit 132 includes a power transmission coil 134 installed on a floor surface of a parking lot, and a capacitor 136 connected in series to the power transmission coil 134. The power transmission resonance circuit 132 is designed such that the resonance frequency is a predetermined frequency Fset (several tens to several hundreds kHz). The high frequency power supply circuit 140 is configured as a circuit that converts power from the AC power supply 190 into power having a predetermined frequency Fset and outputs the power to the power transmission resonance circuit 132, and includes a filter, a frequency conversion circuit, a leakage breaker, and the like.

  Although not shown, power transmission ECU 170 is configured as a microprocessor centered on a CPU, and includes a ROM for storing processing programs, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The power transmission ECU 170 detects by converting the current Itr of the power transmission resonance circuit 132 from the current sensor 150 that detects the AC current flowing in the power transmission resonance circuit 132 and the AC voltage between the terminals of the power transmission resonance circuit 132 into a DC voltage. The voltage (transmission voltage) Vtr between terminals of the resonance circuit 132 for power transmission from the voltage detection unit 152 to be input is input via the input port. The voltage detection unit 152 includes a rectifier circuit and a voltage sensor. From the power transmission ECU 170, a control signal to the high-frequency power supply circuit 140 is output via an output port.

  The automobile 20 is configured as an electric vehicle, and includes a traveling motor 22, an inverter 24 for driving the motor 22, a battery 26 that exchanges electric power with the motor 22 via the inverter 24, and the inverter 24 and the battery. 26, a system main relay 28, a power receiving unit 31 connected to the battery 26, a vehicle electronic control unit (hereinafter referred to as “vehicle ECU”) 70 for controlling the entire vehicle, and a vehicle ECU 70. And a communication unit 80 that communicates with the communication unit 180 of the power transmission device 130 and performs wireless communication.

  The power receiving unit 31 includes a power receiving resonance circuit 32, a charging circuit 40 provided between the power receiving resonance circuit 32 and the battery 26, and a charging circuit provided between the power receiving resonance circuit 32 and the charging circuit 40. The relay 42 includes a relay 44 and a resistor 46 that are connected between the power receiving resonance circuit 32 and the charging relay 42 and in parallel with the power receiving resonance circuit and in series with each other. Here, the power receiving resonance circuit 32 includes a power receiving coil 34 installed on the bottom surface (floor panel) of the vehicle body, and a capacitor 36 connected in series to the power receiving coil 34. The power receiving resonance circuit 32 is designed such that the resonance frequency becomes a frequency (ideally, the predetermined frequency Fset) near the predetermined frequency Fset (resonance frequency of the power transmission resonance circuit 132). The charging circuit 40 is configured as a circuit capable of converting AC power received by the power receiving resonance circuit 32 into DC power and supplying the DC power to the battery 26, and includes a rectifier circuit, a smoothing circuit, and the like. The charging relay 42 connects and disconnects the power receiving resonance circuit 32 side and the charging circuit 42 side. The relay 44 is a resistor having one terminal connected to a positive line between the power receiving resonance circuit 32 and the charging relay 42 and a negative line between the power receiving resonance circuit 32 and the charging relay 42. Connection to and release from the other terminal.

  Although not shown, the vehicle ECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The vehicle ECU 70 detects the rotational position θm of the rotor of the motor 22 from the rotational position detection sensor that detects the rotational position of the rotor of the motor 22 and the current that detects the phase current flowing in each phase of the three-phase coil of the motor 22. Phase currents Iu, Iv, Iw from the sensor, a battery voltage Vb from a voltage sensor 27a installed between terminals of the battery 26, a battery current Ib from a current sensor 27b attached to a positive terminal of the battery 26, and the battery 26 The battery temperature Tb from the temperature sensor that detects the temperature of the battery is input via the input port. The vehicle ECU 70 also includes an ignition signal from an ignition switch (start switch), a shift position SP from a shift position sensor that detects the operation position of the shift lever, and an accelerator from an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal. The opening degree Acc, the brake pedal position BP from the brake pedal position sensor that detects the depression amount of the brake pedal, the vehicle speed V from the vehicle speed sensor, and the vehicle height Hv from the vehicle height sensor 74 are input via the input port. Further, the vehicle ECU 70 supplies the current Ire of the power receiving resonance circuit 32 from the current sensor 50 that detects the alternating current flowing in the power receiving resonance circuit 32, the voltage between the terminals of the power receiving resonance circuit 32 from the voltage detection unit 52 (power reception). Voltage) Vre1, the voltage Vre2 between the input sides of the charging circuit 40 from the voltage detection unit 54, the voltage Vre3 between the terminals of the resistor 46 from the voltage detection unit 56, and the substrate mounted with the power receiving resonance circuit 32. The temperature Tre of the power receiving resonance circuit 32 from the temperature sensor is input via the input port. The voltage detection unit 52 includes a rectifier circuit that converts an AC voltage between terminals of the power receiving resonance circuit 32 into a DC voltage, and a voltage sensor that detects the converted DC voltage. The voltage detection unit 54 is provided between the charging circuit 40 and the charging relay 42 and converts an AC voltage between the positive electrode side line and the negative electrode side line (voltage between terminals on the input side of the charging circuit 40) into a DC voltage. A rectifier circuit; and a voltage sensor that detects the converted DC voltage. The voltage detection unit 56 includes a rectifier circuit that converts an AC voltage between the terminals of the resistor 46 into a DC voltage, and a voltage sensor that detects the converted DC voltage. From the vehicle ECU 70, a switching control signal to a switching element (not shown) of the inverter 24, an on / off signal to the system main relay 28, an on / off signal to the charging relay 42, an on / off signal to the relay 44, and a display 72 for displaying and outputting information. A display control signal or the like (for example, a display of a navigation device) is output via an output port. The vehicle ECU 70 calculates the storage ratio SOC of the battery 26 based on the integrated value of the battery current Ib of the battery 26 detected by the current sensor 27b.

  Here, in the embodiment, the power receiving device 30 mainly corresponds to the power receiving unit 31, the vehicle ECU 70, and the communication unit 80.

  In the non-contact power transmission / reception system 10 of the embodiment configured as described above, the power transmission coil 134 of the power transmission resonance circuit 132 and the power reception coil 34 of the power reception resonance circuit 32 are close to each other, and the charging relay 42 or the relay 44. When the power of the predetermined frequency Fset is supplied from the AC power supply 190 to the power transmission resonance circuit 132 via the high frequency power supply circuit 140 when the power is turned on, the power transmission coil 134 and the power reception coil 34 generate an electromagnetic field. Energy (electric power) is transmitted from the power transmission coil 134 to the power reception coil 34. The energy transmission by the resonance is performed when the Q value indicating the resonance intensity between the power transmission coil 134 and the power reception coil 34 is equal to or greater than a predetermined value Qref (for example, 100).

  Next, the operation when such power transmission is performed will be described. FIG. 3 is a flowchart illustrating an example of power transmission start processing executed by the power transmission ECU 170 when power transmission is started. When the power transmission start process is executed, the power transmission ECU 170 first inputs the vehicle height Hv (step S100), and the vehicle height direction distance Lv between the power transmission coil 134 and the reception coil 34 from the input vehicle height Hv. Is estimated (step S110). Here, in the embodiment, the vehicle height Hv is input by receiving the vehicle height sensor 74 attached to the automobile 20 and transmitting the vehicle height Hv. For the distance Lv in the vehicle height direction, the vehicle height Hv is used as it is, or the difference between the mounting height of the vehicle height sensor 74 and the height of the center position of the power receiving coil 34 is determined as a predetermined value in advance. A value obtained by subtracting a predetermined value from Hv can be used.

  Subsequently, the output impedance Zs of the high-frequency power supply circuit 140 is calculated based on the voltage Vs detected by the voltage detection unit 152 and the current Is detected by the current sensor 150 (step S120). Then, a coupling coefficient k is obtained based on the output impedance Zs (step S130). The output impedance Zs can be expressed as a function of the coupling coefficient k as shown in the following equation (1). In Equation (1), “ω” is the angular frequency, “L1” is the self-inductance of the power transmission coil 134, “L2” is the self-inductance of the power reception coil 34, and “RL” is closer to the charging circuit 40 than the power reception unit 31. Load resistance.

  Then, the distance Lh in the plane direction of the winding plane between the power transmission coil 134 and the power reception coil 34 is estimated based on the coupling coefficient k (step S140). In the embodiment, the distance Lh in the planar direction is determined as a planar distance setting map by previously obtaining the relationship between the coupling coefficient k and the distance Lh in the planar direction between the power transmission coil 134 and the power reception coil 34 by experiments or the like. It is stored and estimated by deriving the corresponding distance Lh in the plane direction from the map when the coupling coefficient k is given.

  Thus, when the distance Lv in the vehicle height direction and the distance Lh in the plane direction are determined from the power transmission coil 134 and the power reception coil 34, the distance between the power transmission coil 134 and the power reception coil 34 (hereinafter referred to as the inter-coil distance). L is calculated (step S150). FIG. 4 schematically shows the method of the embodiment when the inter-coil distance L is obtained. Then, a transmittable power map is selected based on the inter-coil distance L (step S160), and the transmittable power is set from the selected map and the distance Lh in the plane direction between the power transmitting coil 134 and the power receiving coil 34 (step S160). S170). FIG. 5 shows an example of a transmittable power map. FIG. 5A is a transmittable power map when the inter-coil distance L is relatively small, and FIG. 5B is a transmittable power map when the inter-coil distance L is relatively large. The maps of FIGS. 5A and 5B are shown as the relationship between the center position of the power receiving coil 34 and the power that can be transmitted with respect to the center position of the power transmitting coil 134, as shown. The power that can be transmitted is set such that the larger the inter-coil distance L is, and the smaller the center of the power receiving coil 34 is away from the center of the power transmitting coil 134 in the plane direction. This is to perform non-contact power transmission / reception efficiently. In addition, the electric power which can be transmitted in FIG. 5 is an illustration, and is not limited to this numerical value. In the embodiment, the transmission power map is selected by comparing the inter-coil distance L with a predetermined value Lref. When the inter-coil distance L is less than the predetermined value L, the map shown in FIG. The map shown in FIG. 5B is selected when the inter-coil distance L is equal to or greater than the predetermined value Lref.

  When the transmittable power is set in this way, the charging time is calculated based on the set transmittable power and the storage ratio SOC of the battery 26 (step S180), and this routine ends. Note that as the storage ratio SOC of the battery 26, a value calculated from the integrated value of the charge / discharge current Ib of the battery 26 detected by the current sensor 27b is received from the vehicle ECU 70. The transmittable power is used for control when power is transmitted from the high frequency power supply circuit of the power transmission device 130 to the power receiving coil 34 via the power transmission unit 131, and the charging time is transmitted to the vehicle ECU 70 and displayed on the display 72 or the like. Is output.

  According to the non-contact power transmission / reception system 10 of the embodiment described above, the distance L between the power transmission coil 134 and the power reception coil 34 in the vehicle height direction estimated from the vehicle height Hv from the vehicle height sensor 74. It can be calculated based on Lv and the distance Lh in the plane direction estimated from the coupling coefficient k obtained based on the output impedance Zs of the high-frequency power supply circuit 140. By simply attaching the vehicle height sensor 74, the distance L between the coils of the power transmission coil 134 and the power reception coil 34 can be obtained more accurately without increasing the number of other components. Further, the transmittable power is set such that the larger the inter-coil distance L is and the smaller the center of the power receiving coil 34 is from the center of the power transmitting coil 134 in the plane direction, the smaller is the power that can be transmitted. Therefore, the charging time can be calculated more accurately.

  In the contactless power transmission / reception system 10 of the embodiment, the power transmission ECU 170 of the power transmission device 130 executes the power transmission start process illustrated in FIG. 3, but the vehicle ECU 70 of the power reception device 30 executes the power transmission start process. Good. In this case, the voltage Vs detected by the voltage detection unit 152 and the current Is detected by the current sensor 150 are received from the power transmission ECU 170 via communication, or the output impedance Zs calculated by the power transmission ECU 170 is received from the power transmission ECU 170 via communication. Alternatively, the coupling coefficient k obtained by the power transmission ECU 170 may be received from the power transmission ECU 170 by communication.

  In the non-contact power transmission / reception system 10 of the embodiment, the automobile 20 includes the vehicle height sensor 74, but the power transmission device 130 may include the vehicle height sensor 74.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the automobile manufacturing industry.

   DESCRIPTION OF SYMBOLS 10 Non-contact power transmission / reception system, 20 Car, 22 Motor, 24 Inverter, 26 Battery, 27a Voltage sensor, 27b Current sensor, 28 System main relay, 30 Power receiving device, 31 Power receiving unit, 32 Power receiving resonance circuit, 34 Power receiving coil , 36 capacitor, 40 charging circuit, 42 charging relay, 44 relay, 46 resistance, 50 current sensor, 52, 54, 56 voltage detection unit, 70 vehicle electronic control unit (vehicle ECU), 72 display, 74 vehicle height sensor , 80 communication unit, 130 power transmission device, 131 power transmission unit, 132 resonance circuit for power transmission, 134 coil for power transmission, 136 capacitor, 140 high-frequency power circuit, 150 current sensor, 152 voltage detection unit, 170 electronic control unit for power transmission (power transmission E U), 180 communication unit, 190 an AC power source.

Claims (1)

A power transmission device having a power transmission coil;
A vehicle having a battery and a power receiving device capable of receiving power from the power transmission device in a non-contact manner using a power receiving coil and charging the battery; and
A non-contact power transmission and reception system comprising:
A vehicle height sensor for detecting the vehicle height;
When power is transmitted from the power transmission device to the power reception device, the output impedance is calculated, and the distance between the power transmission coil and the power reception coil is calculated based on the output impedance and the vehicle height. Means for controlling the transmission of power,
A non-contact power transmission / reception system comprising:

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