JP2012070463A - Non-contact power supply device - Google Patents

Abstract

Power transmission efficiency is improved in a non-contact power supply device.
AC power is input to a power transmission device having a power transmission coil that is energized, a power reception device having a power reception coil that receives power from the power transmission device by at least magnetic coupling, and AC power to the power transmission coil. The oscillation means 14, the detection means 19 for detecting the distance between the power transmission coil and the power reception coil, and the greater the distance detected by the detection means, the higher the oscillation frequency of the AC power by the oscillation means, And a control means 16 for setting the oscillation frequency lower as the distance is smaller.
[Selection] Figure 1

Description

  The present invention relates to a non-contact power feeding device.

  Non-contact power feeding that charges the battery by rectifying the alternating current induced in the secondary coil by electromagnetic induction by passing alternating current through the primary coil with the primary coil on the power transmission side facing the secondary coil on the power receiving side The device is known. In this type of power supply device, if the primary coil and the secondary coil are misaligned, the power transmission efficiency decreases, so look for an oscillation frequency that maximizes the input power supplied to the primary coil, and use the power at this oscillation frequency. What to supply is proposed (patent document 1).

JP 2010-22076 A

  However, even when the maximum value of the input power is detected and the power is supplied at the oscillation frequency at which the input power is maximized as in the conventional technique, the output power may not be maximized. Therefore, it cannot be said that the power transmission efficiency is high.

  The problem to be solved by the present invention is to increase the power transmission efficiency in the non-contact power feeding apparatus.

  The present invention solves the above problem by detecting the distance between the power transmission coil and the power reception coil, and increasing the oscillation frequency as the distance increases and decreasing the oscillation frequency as the distance decreases.

  According to the present invention, since the distance between the power transmission coil and the power reception coil correlates with the coupling coefficient, and the coupling coefficient correlates with the output power, the power transmission efficiency can be increased.

It is a block diagram which shows the non-contact electric power feeding system to which one embodiment of this invention is applied. It is a block diagram which shows the control part 16 of FIG. It is a figure which shows an example of the carrier used in the control part 16 of FIG. It is a time chart which shows the example of a production | generation of SW pulse in the control part 16 of FIG. It is the top view and perspective view which show the state which the power transmission coil L1 and the receiving coil L2 of FIG. 1 opposed. It is the top view and perspective view which show the state which the power transmission coil L1 and the receiving coil L2 of FIG. 1 opposed, and is a figure which shows the case where it shift | deviates to the X-axis direction. 6 is a graph showing an example of a change in the coupling coefficient κ when the power receiving coil L2 shown in FIGS. 5A and 5B is displaced in the X-axis direction and the Z-axis direction. In FIG. 6, it is a graph which shows the relationship between the distance L between the power transmission coil L1 and the receiving coil L2, and coupling coefficient (kappa). In the driving frequency f1, it is a graph with the vertical axis representing the inverter output voltage V _inv and the inverter output current I _inv , and the horizontal axis representing the coupling coefficient κ and the distance L. In the driving frequency f2, the vertical axis is an inverter output voltage V _inv and the inverter output current I _inv , and the horizontal axis is a coupling coefficient κ and a distance L. It is a figure which shows the electric power feeding possible range in the electric power feeding range of coupling coefficient (kappa) = 0-1. It is a block diagram which shows the structure of the frequency control part 17 of FIG.1 and FIG.2. It is a figure which shows an example of the control map which has the relationship between the distance L and the frequency value fn. It is a figure which shows an example of the control map which has the relationship between coupling coefficient (kappa) and the frequency value fn. It is a block diagram which shows the structure of the frequency control part 17 which concerns on other embodiment (2nd Embodiment) of this invention. FIG. 15 is a diagram showing an example of a control map having a relationship between an output current i _inv and a frequency value fn according to the embodiment of FIG. 14. It is a block diagram which shows the structure of the frequency control part 17 which concerns on further another embodiment (3rd Embodiment) of this invention. It is a block diagram which shows the structure of the frequency control part 17 which concerns on other embodiment (4th Embodiment) of this invention. Is a graph showing an example of a control map having a relationship between the input impedance Z _in and the frequency value fn in accordance with the embodiment of Figure 17. It is a figure which shows an example of the control map which has the relationship between the distance L and frequency value fn which concerns on further another embodiment (5th Embodiment) of this invention. It is a figure which shows the electric power feeding possible range in the electric power feeding range of coupling coefficient (kappa) = 0-1 based on embodiment of FIG. It is a figure which shows an example of the control map which has the relationship between the distance L and frequency value fn which concerns on further another embodiment (modification of 5th Embodiment) of this invention. It is a characteristic view of inverter voltage V _inv and inverter current I _inv when the drive frequency f1 of the inverter is constant. It is a figure which shows an example of the control map which has the relationship between the distance L according to a battery state (load state) and the frequency value fn. It is a block diagram which shows the non-contact electric power feeding system to which further another embodiment (6th Embodiment) of this invention is applied. ₂₅ is a graph in which the vertical axis represents the inverter output voltage V _inv and the inverter output current I _inv and the horizontal axis represents the coupling coefficient κ and the distance L when the drive frequency is f1 in the non-contact power feeding system of FIG. ₂₅ is a graph in which the vertical axis represents the inverter output voltage V _inv and the inverter output current I _inv and the horizontal axis represents the coupling coefficient κ and the distance L when the drive frequency is f2 in the non-contact power feeding system of FIG.

<< First Embodiment >>
FIG. 1 shows a non-contact power feeding system 1 to which an embodiment of the present invention is applied, which includes a power transmitting device 10 and a power receiving device 50, and is mounted on a vehicle or the like from a power transmitting device 10 installed on a power supply stand or the like. In this system, power is supplied to a load 53 such as a battery of the power receiving device 50 in a contactless manner and charged.

The power transmission device 10 of this example includes an AC power supply unit 11 of a commercial power supply (frequency is 50 Hz in eastern Japan, frequency is 60 Hz in west Japan), a DC power supply unit 12 that converts an AC voltage transmitted from the AC power supply unit 11 into a DC voltage, The voltage type inverter unit 13, the power transmission coil (primary coil) L ₁ for supplying the high frequency power output from the voltage type inverter unit 13 to the power receiving device 50 in a contactless manner, and the power transmission coil L ₁ are provided in parallel to transmit power. And a primary capacitor C _1P constituting the resonance circuit 15 of the device 10.

The DC power supply unit 12 includes a diode D ₁ and a diode D ₂ , a diode D ₃ and a diode D ₄ , a diode D ₅ and a diode D ₆ , which are connected in parallel, and the AC power supply unit 11 is connected to each intermediate connection point. Three-phase output terminal is connected.

The voltage type inverter unit 13 includes switching elements S _{1 to} S ₄ such as MOSFETs, diodes D _{7 to} D ₁₀ connected in reverse parallel to these MOSFETs, and a DC voltage smoothing capacitor C 3. The DC voltage output from the unit 12 is inversely converted into high frequency power of about 1 to 50 kHz.

Then, the intermediate connection point of the switching elements _{S 1} and _{S 2,} each of the intermediate connection point of the switching elements _{S 3} and _{S 4,} the resonant circuit 15 is connected comprising a transmitting coil _{L 1} and the primary capacitor _{C 1P} ing. The AC power supply unit 11, the DC power supply unit 12, and the voltage type inverter unit 13 are also referred to as a high frequency AC power supply unit 14.

The power receiving device 50 is provided in parallel and in series with the power receiving coil (secondary coil) L ₂ that receives high-frequency power from the power transmitting coil L ₁ of the power transmitting device 10 in a non-contact state by electromagnetic induction, and the power receiving coil L _2. Secondary capacitors C _2P and C _2S that constitute the resonance circuit 52 of the power receiving device 50, a rectifying unit 51 that rectifies high-frequency power received by the power receiving coil L ₂ , and a load 53 that includes a battery of a secondary battery, etc. Prepare.

Rectifier 51 includes a diode _{D 11} and a diode _{D 12} connected in series with each other, the diode _{D 13} and a diode _{D 14} are connected in parallel, the respective intermediate connection points, the receiving coil _{L 2} and the secondary capacitor _{C 2P,} The output terminal of the resonance circuit 52 composed of _C2S is connected. The output terminal of the rectifying unit 51 is connected to the load 53.

  The non-contact power feeding system 1 of this example includes a control unit 16 that controls the voltage type inverter unit 13 in addition to the power transmission device 10 and the power receiving device 50 described above. The control unit 16 may be provided in the power transmission device 10, may be provided in the power reception device 50, or may be provided independently. Although not shown, a load control unit that monitors the charge state of the load 53 such as a battery and generates a command value for charging power, and the power command value generated by the load control unit are wirelessly transmitted to the power transmission device 10. A wireless communication unit such as Bluetooth (registered trademark) that communicates and a charging start switch for notifying the power transmission device 10 that the user starts charging are provided.

The control unit 16 includes a frequency control unit 17 that controls the frequency of the output voltage of the voltage type inverter unit 13, a voltage command generation unit 18 that controls the pulse width of the output voltage of the voltage type inverter unit 13 and generates a switching pulse, Is provided. FIG. 2 shows a detailed configuration of the control unit 16.

As shown in FIG. 2, the frequency control unit 17 includes a frequency command generation unit 17A and a carrier generation unit 17B, and the frequency command generation unit 17A has a frequency command value f _{ref of} power output from the voltage type inverter unit 13. The carrier generation unit 17B calculates the carrier amplitude Vx based on the frequency command value and generates a carrier.

For example, when a carrier is generated by analog control, assuming that the slope of the carrier is dv / dt as shown in FIG. 3A, Vx = (dv / dt) · (1 / f _ref ) and the carrier amplitude Vx Ask for. On the other hand, in the case of digital control, if the carrier is generated by increasing the digital oscillation frequency by fc [Hz] by one count, as shown in FIG. 3B, the carrier is expressed by Vx = fc / f _ref. Is obtained. However, the carrier amplitude Vx is an integer.

Returning to FIG. 2, the voltage command generation unit 18 compares the voltage amplitude command generation unit 18 </ b _{> A} that generates the output voltage amplitude command value V _ref of the voltage type inverter unit 13 with the output voltage amplitude command value V _ref and the carrier. An SW pulse generator 18B that generates a switching pulse is included.

The voltage amplitude command generation unit 18A obtains a voltage amplitude command value V _ref from a power command value P _ref given from the outside with reference to a map or the like obtained in advance by experiments or calculations.

As shown in FIG. 4, the SW pulse generation unit 18B determines a pulse as follows from the comparison between the carrier and the voltage amplitude commands V _ref and Vx.

Switching element S ₁ is ON when carrier ≦ Vx / 2, OFF when carrier> Vx / 2, and switching element S ₂ is OFF when carrier ≦ Vx / 2, and ON when carrier> Vx / 2. The switching element S ₃ is ON when carrier ≧ V _ref and carrier ≦ V _ref + Vx / 2, and is OFF when carrier <V _ref or carrier> V _ref + Vx / 2, and the switching element S ₄ is carrier ≧ V _ref and OFF when carrier ≦ V _ref + Vx / 2, ON when carrier <V _ref or carrier> V _ref + Vx / 2.

Further, SW pulse generator 18B is provided between the switching element S ₁ and S _3, and, between the switching element S ₂ and S _4, the arm short circuit between the positive and negative electrodes to produce a dead time so as not to generate . In this way, as shown in the lower part of the time chart of FIG. 4, the output line voltage V _inv of the voltage type inverter unit 13 is changed to a rectangular wave AC, and a positive voltage (+ V _dc ) and a negative voltage (−V _dc ). Can control the pulse width.

The voltage type inverter unit 13 may be controlled by using a triangular wave carrier comparison method in addition to using the sawtooth wave described above. Moreover, the control method of the voltage type inverter part 13 mentioned above is an example, Comprising: Another control method can also be used. For example, the control configuration may be configured by a feedback system that detects a load output such as voltage and power and sets the power command _Pref . Since the vehicle is equipped with a battery controller that controls the state of charge of the battery, the information may be obtained by communication and used as the power command _Pref . Further, an insulating transformer may be provided between the voltage-type inverter unit 13 and the power transmission side resonance circuit 15, and a capacitor constituting the resonance circuit may be connected to the primary side of the insulation transformer. The high frequency AC power supply 14 includes a three-phase AC power supply 11, a rectifier 12, a smoothing capacitor C _3, is shown an example constituted by a voltage-type inverter unit 13, a high frequency alternating current power supply 14 includes a switching power supply If it is.

  Next, with reference to FIG. 5 and FIG. 6, it will be described that the coupling coefficient κ between the power transmission coil L1 and the power reception coil L2 changes. 5A and 5B are a plan view a) showing a state where the power transmission coil L1 (power transmission coil) and the power reception coil L2 (power reception coil) face each other, and perspective views b) and c). 5A and 5B, the X axis and the Y axis indicate planar directions of the power transmission coil L1 and the power reception coil L2, and the Z axis indicates the height direction. For the purpose of this description, the power transmission coil L1 and the power reception coil L2 are both formed in the same circular shape, but in this example, it is not always necessary to have a circular shape, and the power transmission coil L1 and the power reception coil L2 have the same shape. There is no need to make it.

  Now, assuming that the power transmission coil L1 is on the ground and the power reception coil L2 is mounted on the vehicle, as shown in FIG. 5A, the power reception coil L2 matches the power transmission coil L1 in the X-axis and Y-axis directions which are planar directions. However, depending on the skill of the driver, as shown in FIG. 5B, the relative positions of the power transmission coil L1 and the power reception coil L2 may be shifted in the plane direction. is there. Further, since the height of the vehicle varies depending on the type of vehicle and the load, the distance in the height direction Z between the power transmission coil L1 and the power reception coil L2 also varies depending on the vehicle height.

  FIG. 6 shows an example of changes in the coupling coefficient κ for the power receiving coil L2 in the X-axis direction and the Z-axis direction shown in FIGS. 5A and 5B. As shown in FIG. 6, when the center of the power transmission coil L1 coincides with the center of the power reception coil L2 (the value of the X axis in FIG. 6 corresponds to zero), the leakage between the power transmission coil L1 and the power reception coil L2 The magnetic flux is small and the coupling coefficient κ is large (κ = 0.8 in the example in the figure). On the other hand, when the positions of the power transmission coil L1 and the power reception coil L2 are shifted in the X-axis direction (or the height in the Z-axis direction is changed), the leakage magnetic flux increases, and the coupling coefficient κ decreases as shown in FIG. (In the example of the figure, κ = 0.1).

FIG. 7 is a graph showing the relationship between the distance L between the power transmission coil L1 and the power reception coil L2 and the coupling coefficient κ. The distance L is the plane of the power reception coil L2 shown in FIGS. 5A, 5B and 6. Using the direction X-axis and the height direction Z-axis, L = √ (X ² + Z ² ) is defined. In this case, the power transmission coil L1 is fixed, and is the distance of the power reception coil L2 with respect to the power transmission coil L1.

By the way, cordless home appliances such as electric toothbrushes and shaving shavers, non-contact power supply devices used for charging portable devices, and non-contact power supply devices for rail systems used in factory lines are power transmission coils. Since the distance between L1 and the power receiving coil L2 does not move relatively, it is not necessary to assume that the coupling coefficient κ varies. Therefore, on the premise of the fixed coupling coefficient κ (or distance L), the resonance circuit of the power transmission device 10 is configured to efficiently supply power to the resonance circuit 52 of the power receiving device 50 under a specific coupling coefficient κ. 15 and a capacitor and an inductor included in the resonance circuit 52 of the power receiving device 50 may be designed.

  However, as described above, when the power transmission coil L1 is installed on the ground (infrastructure side), the power reception coil L2 is mounted on the vehicle, and the battery 53 of the vehicle is charged in a non-contact manner, The coupling coefficient κ (distance L) varies greatly depending on the state. Therefore, in order to cope with a change in the coupling coefficient κ (distance L) due to a positional deviation at the time of parking or a vehicle height, it is necessary to determine a power supply range in which desired output power is supplied. The desired output power (target power) refers to the charging power (for example, 6 kW, 10 kW) that charges the battery 53, and the power supply range refers to the desired output power that allows a change in the coupling coefficient κ (distance L). The range where power is supplied.

In FIG. 8, the vertical axis represents the inverter output voltage V _inv (output voltage of the high-frequency AC power supply 14) and the inverter output current I _inv (output current of the high-frequency AC power supply 14), and the horizontal axis represents the coupling coefficient κ and the distance L. It is a graph. The driving frequency of the voltage type inverter unit 13 is constant f1.

Here, the voltage type inverter unit 13 has a power supply capacity of an allowable voltage V _max and an allowable current I _{max according to} the specifications of the device, and therefore can obtain a desired output power only within a power supply range within the power supply range. . In the example of FIG. 8, it is determined by a range that is limited by the allowable voltage V _max and the allowable current I _max of the voltage type inverter unit 13. However, outside the power supply range, a desired output power value cannot be obtained, and power supply cannot be performed. For example, if the desired output power value is 6 kW, the supplied power is lowered so as not to reach V _max and I _max , and therefore the power value that can be supplied is reduced to 5 kW and 3 kW outside the power supply possible range.

  Certainly, if the inverter is driven by an inverter having a power source capacity that allows the maximum value of the inverter voltage and the maximum value of the current required in the power supply range, desired output power can be obtained in the power supply range. However, this leads to an increase in cost.

FIG. 9 is a graph in which the vertical axis represents the inverter output voltage V _inv and the inverter output current I _inv and the horizontal axis represents the coupling coefficient κ and the distance L, as in FIG. In this example, the frequency is f2, which is different from f1 in FIG. The power supply capacities V _max and I _{max of} the inverter and the power supply range are the same as in FIG.

Also in this case, since the drive frequency of the inverter is set to f2, desired output power can be obtained with respect to the power supply range only in the power supply range shown in FIG. Voltage type inverter unit 13, because the tolerance for having a power supply capacity of the voltage _{V max} and permissible current _{I max,} determined by the extent that restricted the permissible voltage _{V max} of the inverter permitted current ^{I max.}

  Therefore, in the non-contact power feeding system 1 of this example, the driving frequencies f1 and f2 of the voltage type inverter unit 13 are set according to the coupling coefficient κ between the power transmitting coil L1 and the power receiving coil L2, specifically the distance L. In this case, the driving frequency is set higher as the coupling coefficient κ is smaller, and the driving frequency is set lower as the coupling coefficient κ is larger. Specifically, the driving frequency is set higher as the distance L between the power transmission coil L1 and the power receiving coil L2 is larger, and the driving frequency is set lower as the distance L is smaller.

FIG. 10 is a diagram showing a power supply possible range in the power supply range where the coupling coefficient κ is 0 to 1, that is, a range in which a desired output power (target power) can be obtained within the power supply range. In the conventional example, the frequency is varied according to the resistance component of the load 53 under the condition that the inverter drive frequency is constant. Therefore, when the coupling coefficient κ (distance L) changes, the power source capacities V _max and I _max are limited. As shown in FIG. 10, the power supply possible range becomes smaller.

On the other hand, in this example, the drive frequency of the voltage-type inverter unit 13 (frequency of the high-frequency AC power supply 14) is determined according to the coupling coefficient κ between the power transmission coil L1 and the power reception coil L2, specifically the distance L. Since the values f1 and f2 are set, the entire power supply range can be set to a power supplyable range. In other words, since the inverter capacity (power capacity) can be minimized thereby reducing the cost of the apparatus (lowered the permissible current I _max).

Next, a method for setting the drive frequency will be described with reference to FIG.
FIG. 11 is a block diagram showing a configuration of the frequency control unit 17 of FIGS. 1 and 2. The frequency command generation unit 17A includes a frequency table 17A1 that determines a frequency value fn by using distance information between the power transmission coil L1 and the power reception coil L2 and load information such as a remaining battery voltage and a resistance component as input values, and a comparator 17A2 outputs a frequency command _{f ref} to the comparator and carrier generation 17B and an initial value _{f 0} of the output frequency value fn and frequency values from the table 17A1.

The initial value f ₀ of the frequency value is the frequency of the carrier in FIGS. 2 and 11 (the frequency of the basic component of the pulse of each switching element S _{1 to} S ₄ in FIG. 4), and the output voltage V _inv of the inverter This is the frequency of the fundamental wave component. Since the output voltage V _{inv of the} inverter is a rectangular wave, in this example, the fundamental wave component is called an inverter drive frequency.

In this example, the initial value f ₀ of the frequency values driving frequency value at high frequency of use state is set. With reference to FIG. 10, the frequency value f ₂ at a large state of the coupling coefficient κ of the power supply range to be powered the desired output power is set. In other words, the frequency value f ₂ is set distance L at the minimum state in the power supply range.

Returning to Figure 11, the comparator 17A2 compares the frequency value fn and the initial value _{f 0} output from the frequency table 17A1, if fn is different from the initial value _{f 0} employs a frequency value fn, frequency command and outputs it to the carrier generating unit 17B as f _ref. Also, if the same frequency value fn output from the frequency table 17A1 is the initial value _{f 0} is directly outputs the initial value _{f 0} to the carrier generator 17B as the frequency instruction fref.

Here, the detection method of the distance L of the distance information input to the frequency table 17A1 is not particularly limited. For example, the position detection camera 19 (see FIG. 1) is mounted on the power transmission coil L1 side or the power reception coil L2 side to form a coil. The distance between them may be detected, or may be detected using a radar or a distance sensor.

  Since the distance L and the coupling coefficient κ are correlated as shown in FIG. 7, a coupling coefficient estimator may be provided to obtain the coupling coefficient κ and set it as the distance L. The coupling coefficient estimator estimates the coupling coefficient κ between the power transmission coil L1 and the power reception coil L2, and is coupled using, for example, the voltage (or current) of the power transmission coil and the voltage (or current) of the power reception coil. The coefficient κ may be estimated, or the coupling coefficient κ may be estimated using the voltage and current values on the power transmission coil side. In this example, it is sufficient that distance information such as the distance L or the coupling coefficient κ is input to the frequency table 17A1, and the specific means is not particularly limited.

  The distance information input to the frequency table 17A1 is preferably updated several times at the start of feeding and during feeding. This is because it is considered that the change in the distance L (coupling coefficient κ) between the power transmission coil L1 and the power reception coil L2 does not occur so frequently once power supply is started. However, the distance L changes because the vehicle height (Z direction) changes when a luggage is taken in and out during power supply or when the vehicle punctures. Therefore, it is preferable to update the distance information several times even during power feeding. The number of updates is not particularly limited, and is updated every few minutes, for example.

  Similarly, it is preferable to update the load information input to the frequency table 17A1 several times at the start of feeding and during feeding. When power supply is started, it is necessary to know how much the remaining capacity of the battery is from the remaining voltage and the resistance component, so it is essential to input the load information. However, since the battery state such as the residual voltage and the resistance component does not change suddenly but depends on the state of charge SOC of the battery, it may be performed several times without being updated in real time during power feeding. The load information can be set by, for example, a battery controller that manages the state of the battery, and update information can be set.

Next, processing in the frequency table 17A1 will be described with reference to FIGS. The frequency table 17A1 includes a control map having a relationship between the distance L and the frequency value fn as shown in FIG. That is, when the distance L is short, the frequency value f2 is set to be relatively small, and when the distance L is long, the frequency value f1 is set to be relatively large (f1> f2). The frequency value fn is determined using the frequency table 17A1 having this control map.

  Further, as described above, since the distance L and the coupling coefficient κ are correlated, a control map having a relationship between the coupling coefficient κ and the frequency value fn as shown in FIG. 13 may be provided. In this case, when the coupling coefficient is large, it is set to a relatively low frequency value f2, and when the coupling coefficient is small, it is set to a relatively high frequency value f1. The frequency value fn can also be determined using the frequency table 17A1 having this control map.

  In the control maps shown in FIGS. 12 and 13, the frequency values f1 and f2 are set so as not to overlap, but the frequency values fn may be overlapped. However, the distance L (coupling coefficient κ) where the frequency value fn overlaps the distance L or the coupling coefficient κ is provided with a hysteresis width or the like so that the frequency value fn does not chatter, and the distance L or the coupling coefficient κ It is desirable to take measures so that the frequency value fn can be determined uniquely.

  According to the above embodiment, since the drive frequency of the voltage type inverter unit 13 is set using the frequency table having the control map of FIG. 12 or FIG. 13, as shown in FIG. The range in which desired power can be supplied even under conditions where Imax) is limited can be expanded, and the power transmission efficiency is increased. In other words, the power supply capacity can be reduced and the cost can be reduced.

<< Second Embodiment >>
14 and 15 are main part block diagrams and control maps showing the second embodiment of the present invention. In this example, the information input to the frequency table 17A1 is different from that of the first embodiment described above. Other configurations are the same. Therefore, the different configuration will be mainly described, and the description related to the first embodiment is used for the common configuration.

FIG. 14 is a block diagram showing a configuration of the frequency control unit 17 of FIGS. 1 and 2. In this example, instead of the distance information of the first embodiment, current information, specifically, inverter output current i _inv is input to the frequency table 17A1. Note that load information such as the remaining voltage and resistance component of the battery is input to the frequency table 17A1 as in the first embodiment.

The current information (inverter output current i _inv ) input to the frequency table 17A1 is the output current i _inv of the inverter when the constant voltage V _inv is applied. For example, the current value output from the inverter when a predetermined voltage such as 200 V is applied at the start of power supply or during power supply is input to the frequency table 17A1.

Next, processing in the frequency table 17A1 will be described with reference to FIG. The frequency table 17A1 includes a control map having a relationship between an output current (inverter output current i _inv ) when a constant voltage is applied and a frequency value fn as shown in FIG. That is, when the output current i _inv is small, it is set to a relatively high frequency value f1, and when the output current i _inv is large, it is set to a relatively low frequency value f2. The frequency value fn is determined using the frequency table 17A1 having this control map. Note that the constant voltage to be applied is the same as the voltage value used when the frequency table 17A1 is provided in advance.

Incidentally, the detection of the output current value i _inv can be detected by providing a current sensor in the output circuit of the voltage type inverter unit 13. The current value at that time is not particularly limited, and may be either a peak hold (I _pk ) or an average value (I _avr ). It suffices if it matches the conditions for creating the control map of the frequency table 17A1.

According to the above embodiment, since the drive frequency of the voltage type inverter unit 13 is set using the frequency table having the control map of FIG. 15, the power source capacities V _max and I _max are as shown in FIG. The range in which desired power can be supplied even under limited conditions can be expanded, and the power transmission efficiency is increased. In other words, the power supply capacity can be reduced and the cost can be reduced.

<< Third Embodiment >>
FIG. 16 is a principal block diagram showing the third embodiment of the present invention. Compared with the second embodiment described above, the information input to the frequency table 17A1 is different and the other configurations are the same. Therefore, different configurations are mainly described, and the descriptions regarding the first and second embodiments are used for the common configurations.

FIG. 16 is a block diagram illustrating a configuration of the frequency control unit 17 of FIGS. 1 and 2. In this example, the load information of the second embodiment is omitted, and only current information, specifically, inverter output information i _inv is input to the frequency table 17A1.

Here, the current information (inverter output current i _inv ) shown in FIG. 16 is the output current i _inv of the inverter having the phase information θi _inv when the constant voltage V _inv is applied. Since this alternating current has a magnitude and a phase, it is possible to estimate the state of a load such as a battery using the two pieces of information and the constant voltage V _inv . Therefore, it is not necessary to input the load information again, the current information (| I _inv |, θi _inv ) can be input, and the load information and the frequency value fn can be set by the frequency table 17A1.

<< 4th Embodiment >>
FIGS. 17 and 18 are main part block diagrams and control maps showing the fourth embodiment of the present invention. In this example, information input to the frequency table 17A1 is different from that of the second embodiment described above. Other configurations are the same. Therefore, different configurations are mainly described, and the descriptions regarding the first and second embodiments are used for the common configurations.

FIG. 17 is a block diagram showing a configuration of the frequency control unit 17 of FIGS. 1 and 2. In this example, instead of the current information of the second embodiment, the output current i _inv of the inverter when the constant voltage V _inv is applied is input to the calculation unit 17A3, and the output current value i _inv of the inverter is calculated by the calculation unit 17A3. The input impedance Z _in is calculated from the applied constant voltage V _inv and used as the input of the frequency table 17A1. Note that load information such as the remaining voltage and resistance component of the battery is input to the frequency table 17A1 as in the first embodiment.

Next, processing in the frequency table 17A1 will be described with reference to FIG. The frequency table 17A1 includes a control map having a relationship between the absolute value | Z _in | of the input impedance viewed from the inverter output side and the frequency value fn as shown in FIG. That is, when the impedance | Z _in | is small, a relatively low frequency value f2 is set, and when the impedance | Z _in | is large, a relatively high frequency value f1 is set. The frequency value fn is determined using the frequency table 17A1 having this control map.

Incidentally, the detection of the output current value i _inv used when calculating the absolute value of the input impedance can be detected by providing a current sensor in the output circuit of the voltage type inverter unit 13. The current value at that time is not particularly limited, and may be either a peak hold (I _pk ) or an average value (I _avr ). It suffices if it matches the conditions for creating the control map of the frequency table 17A1.

In addition, instead of inputting the load information to the frequency table 17A1 in FIG. 17, an inverter output current i _inv having phase information θ _iinv when a constant voltage V _inv is applied as current information (inverter output current) is input. May be. As described in the third embodiment, when the calculation of the input impedance Z _in is performed by outputting the impedance magnitude | Z _in | and the phase θ _Zin from the calculation unit 17A3, the load information and the frequency fn are obtained in the frequency table 17A1. Can be set.

<< 5th Embodiment >>
In each of the embodiments described above, the drive frequency fn of the voltage-type inverter unit 13 is set to a relatively high frequency f1 and a relatively low frequency f2 according to the coupling coefficient κ, the distance L, the inverter output current value iinv, or the impedance Zin. Although set to any one, it may be set to three or more frequencies f1, f2, f3,... Fn.

FIG. 19 is a graph illustrating a case where the frequency table 17A1 of the first embodiment illustrated in FIG. 12 includes four frequency values fn corresponding to the distance L as set values. Note that the frequency value setting method is the same as in the case of two frequency values fn. In this example, by using four types of drive frequency values of the voltage type inverter unit 13 and setting according to the distance L in addition to the load state, as shown in FIG. 20, the power supply range is more than that of the first to fourth embodiments. Can be further expanded. That is, the range in which desired power can be supplied even under conditions where the power supply capacities V _max and I _max are limited can be expanded. Therefore, the power source capacity can be reduced and the cost can be reduced.

  The number of frequency setting values is not limited as long as the power supply range can be covered. Further, in the example shown in FIG. 19, four discrete drive frequencies f1 to f4 are set, but a continuous drive frequency fn may be set as shown in FIG.

Here, the load information such as the remaining battery voltage and the resistance component input to the frequency table 17A1 will be described. FIG. 22 is a characteristic diagram of the inverter voltage V _inv and the inverter current I _inv when the drive frequency f1 of the inverter is constant. 22A, the vertical axis represents the inverter voltage V _inv , the horizontal axis represents the coupling coefficient κ (distance L), and in FIG. 22B, the vertical axis represents the inverter current I _inv , and the horizontal axis represents the coupling coefficient κ (distance L). The characteristics are shown.

In FIG. 22A, a state in which the state of the load (the amount of charge of the battery) has changed from the characteristic V _inv A in FIG. 8 is shown as V _inv B. In FIG. 22B, a state in which the load state (battery charge amount) has changed from the characteristic I _inv A in FIG. 8 is shown as I _inv B.

As shown in FIG. 22, when the battery state changes, the inverter voltage V _inv and the inverter current I _inv change, and accordingly, the power supply possible range also changes. Therefore, as shown in FIG. 23, it is necessary to provide a frequency table corresponding to the battery state. For example, battery state A and battery state B.

<< 6th Embodiment >>
The configuration of the resonance circuits 15 and 52 according to the present invention is not particularly limited and can be variously changed. FIG. 24 is a block diagram showing the non-contact power feeding device according to this example, and the difference from the example shown in FIG. 1 is the configuration of the resonance circuit 52 of the power receiving device 50. That is, the resonance circuit 52 of the power receiving device 50 of the present example includes the power receiving coil L2 and the capacitor _C2P connected in parallel to the power receiving coil L2.

FIG. 25 is a characteristic diagram corresponding to FIG. 8 and FIG. 26 is a characteristic diagram corresponding to FIG. 9, respectively, because the resonance circuits 15 and 52 (the parallel capacitor C _1p before the power transmission coil L1 and the parallel capacitor C _2p after the power reception coil L2) are different. Therefore, the characteristics of the inverter current I _inv and the inverter voltage V _inv are different. Compared with the resonance circuits 15 and 52 according to the first to fifth embodiments, the power supply range is narrowed when the frequency is set to a constant f1.

However, even when the resonance circuits 15 and 52 of FIG. 24 are used, the distance L between the power transmission coil L1 and the power reception coil L2, the coupling coefficient κ, the inverter output current i _inv , and the power transmission device 10 as in this example. By setting the drive frequency of the voltage type inverter unit 13 according to the impedance Z _in , desired power can be supplied even under conditions where the power source capacities V _max and I _max are limited as shown in FIGS. The possible range can be expanded. Therefore, the power source capacity can be reduced and the cost can be reduced.

  The high-frequency AC power supply unit 14 corresponds to the oscillation unit according to the present invention, the control unit 16 corresponds to the control unit according to the present invention, and the position detection camera 19 corresponds to the detection unit according to the present invention.

1 ... non-contact power supply system 10 ... power transmission apparatus 11 ... AC power supply unit 12 ... DC power supply 13 ... voltage type inverter unit D ₁ to D _{10 ...} diodes C _1P, C ₃ ... capacitors S ₁ to S ₄ ... MOSFET
L ₁ ... power transmission coil 14 ... high-frequency AC power supply unit 15 ... resonance circuit 16 ... control unit 17 ... frequency control unit 17A ... frequency command generation unit 17B ... carrier generation unit 18 ... voltage command generation unit 18A ... voltage amplitude command generation unit 18B ... SW pulse generator 19 ... position detection camera 50 ... power receiving device L ₂ ... power receiving coils D _{11 to} D ₁₄ ... diode C _2S , C _2P ... capacitor 51 ... rectifier 52 ... resonance circuit 53 ... load

Claims (14)

A power transmission device having a power transmission coil to be energized;
A power receiving device having a power receiving coil for receiving power from the power transmitting device by at least magnetic coupling;
Oscillating means for inputting AC power to the power transmission coil;
Detection means for detecting a distance between the power transmission coil and the power reception coil;
Control means for setting the oscillation frequency of the AC power by the oscillation means higher as the distance detected by the detection means is larger, and setting the oscillation frequency lower as the distance is smaller. Contact power supply device. A non-contact power feeding device including a power transmission device that transmits electric power at least by magnetic coupling to a power receiving device,
The power transmission device is:
A power transmission coil to be energized;
Oscillating means for inputting AC power to the power transmission coil;
Detection means for detecting a distance between the power transmission coil and a power reception coil of the power reception device;
Control means for setting the oscillation frequency of the AC power by the oscillation means higher as the distance detected by the detection means is larger, and setting the oscillation frequency lower as the distance is smaller. Contact power supply device. A non-contact power feeding device including a power receiving device that receives power from a power transmitting device by at least magnetic coupling,
The power receiving device is:
A power receiving coil for receiving power from the power transmitting device;
Detecting means for detecting a distance between the power receiving coil and the power transmitting coil of the power transmitting device;
Control means for setting the oscillation frequency of AC power input to the power transmission coil to be higher as the distance detected by the detection means is larger, and setting the oscillation frequency to be lower as the distance is smaller. Non-contact power feeding device. A power transmission device having a power transmission coil to be energized;
A power receiving device having a power receiving coil for receiving power from the power transmitting device by at least magnetic coupling;
Oscillating means for inputting AC power to the power transmission coil;
Detection means for detecting a coupling coefficient between the power transmission coil and the power reception coil;
Control means for setting the oscillation frequency of the AC power by the oscillation means to be higher as the coupling coefficient detected by the detection means is smaller, and setting the oscillation frequency to be lower as the coupling coefficient is larger. A non-contact power feeding device. A non-contact power feeding device including a power transmission device that transmits electric power at least by magnetic coupling to a power receiving device,
The power transmission device is:
A power transmission coil to be energized;
Oscillating means for inputting AC power to the power transmission coil;
Detection means for detecting a coupling coefficient between the power transmission coil and the power reception coil of the power reception device;
Control means for setting the oscillation frequency of the AC power by the oscillation means to be higher as the coupling coefficient detected by the detection means is smaller, and setting the oscillation frequency to be lower as the coupling coefficient is larger. A non-contact power feeding device. A non-contact power feeding device including a power receiving device that receives power from a power transmitting device by at least magnetic coupling,
The power receiving device is:
A power receiving coil for receiving power from the power transmitting device;
Detecting means for detecting a coupling coefficient between the power receiving coil and the power transmitting coil of the power transmitting device;
Control means for setting the oscillation frequency of the AC power input to the power transmission coil to be higher as the coupling coefficient detected by the detection means is smaller, and setting the oscillation frequency to be lower as the coupling coefficient is larger. A non-contact power feeding device. A power transmission device having a power transmission coil to be energized;
A power receiving device having a power receiving coil for receiving power from the power transmitting device by at least magnetic coupling;
Oscillating means for inputting AC power to the power transmission coil;
Current detection means for detecting a current of the power transmission coil when AC power of a predetermined voltage is input;
Control means for setting the oscillation frequency of the AC power by the oscillation means to be higher as the current value detected by the current detection means is larger, and setting the oscillation frequency to be lower as the current value is smaller. A non-contact power feeding device. A non-contact power feeding device including a power transmission device that transmits electric power at least by magnetic coupling to a power receiving device,
The power transmission device is:
A power transmission coil to be energized;
Oscillating means for inputting AC power to the power transmission coil;
Current detection means for detecting a current of the power transmission coil when AC power of a predetermined voltage is input;
Control means for setting the oscillation frequency of the AC power by the oscillation means to be higher as the current value detected by the current detection means is larger, and setting the oscillation frequency to be lower as the current value is smaller. A non-contact power feeding device. A non-contact power feeding device including a power receiving device that receives power from a power transmitting device having a power transmission coil by at least magnetic coupling,
The power receiving device is:
A power receiving coil for receiving power from the power transmitting device;
Current detection means for detecting a current of the power transmission coil when AC power of a predetermined voltage is input;
Control means for setting the oscillation frequency of AC power input to the power transmission coil to be higher as the current value detected by the current detection means is larger, and setting the oscillation frequency to be lower as the current value is smaller. A non-contact power feeding device. A power transmission device having a power transmission coil to be energized;
A power receiving device having a power receiving coil for receiving power from the power transmitting device by at least magnetic coupling;
Oscillating means for inputting AC power to the power transmission coil;
Impedance detection means for detecting impedance viewed from the power transmission device side;
Control means for setting the oscillation frequency of the AC power by the oscillation means higher as the impedance value detected by the impedance detection means is larger, and setting the oscillation frequency lower as the impedance value is smaller. A non-contact power feeding device. A non-contact power feeding device including a power transmission device that transmits electric power at least by magnetic coupling to a power receiving device,
The power transmission device is:
A power transmission coil to be energized;
Oscillating means for inputting AC power to the power transmission coil;
Impedance detection means for detecting impedance viewed from the power transmission device side;
Control means for setting the oscillation frequency of the AC power by the oscillation means higher as the impedance value detected by the impedance detection means is larger, and setting the oscillation frequency lower as the impedance value is smaller. A non-contact power feeding device. A non-contact power feeding device including a power receiving device that receives power from a power transmitting device having a power transmission coil by at least magnetic coupling,
The power receiving device is:
A power receiving coil for receiving power from the power transmitting device;
Impedance detection means for detecting impedance viewed from the power transmission device side;
Control means for setting the oscillation frequency of AC power input to the power transmission coil to be higher as the impedance value detected by the impedance detection means is larger, and setting the oscillation frequency to be lower as the impedance value is smaller. A non-contact power feeding device. In the non-contact electric power feeder as described in any one of Claims 1-12,
The non-contact power feeding apparatus, wherein the control means sets the oscillation frequency of the AC power discretely or continuously. In the non-contact electric power feeder as described in any one of Claims 1-13,
The power transmission device includes a capacitor connected in parallel to the power transmission coil,
The power receiving device includes a capacitor connected in parallel to the power receiving coil and a capacitor connected in parallel to the power receiving device.

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