JPWO2014087889A1 - Non-contact power feeding apparatus and control method thereof - Google Patents

Abstract

The non-contact power feeding device (1) is non-contact by at least magnetic coupling between a power feeding side circuit (10) having a first coil (L1) and a power receiving side circuit (20) having a second coil (L2). The electric power is transmitted or received at the same time, and the magnetic pole direction of the first coil (L1) is the same as the magnetic pole direction of the second coil (L2) at the time of power transmission and reception. And a power control unit (15) for driving the inverter (14) to generate high-frequency power to be supplied to the first coil (L1). The power control unit (15) is higher than the resonance frequency of the power receiving side circuit (20), and a combined ampere turn of the first coil (L1) and the second coil (L2) is generated by the power receiving side circuit (20). A frequency within a range smaller than the combined ampere turn at the resonance frequency is selected to drive the inverter (14).

Description

  The present invention relates to a non-contact power feeding device and a control method thereof.

  Conventionally, a non-contact power supply apparatus that charges a load such as a battery in a non-contact manner is known. Such a non-contact power feeding device includes a power supply side coil and a charging side coil, and is configured to transmit and charge high-frequency power by electromagnetic induction. The non-contact power supply apparatus is set so that the primary capacitor on the power transmission side resonates at the same resonance frequency as the inductance component on the secondary side including the load, and the power factor is set to “1”.

  In addition, as a non-contact power feeding device, a device that controls the frequency of high-frequency power according to the resistance component of a load has been proposed in order to perform efficient power transmission. In this non-contact power supply device, even if the resistance component of the load changes, the power factor of the supplied power can be set to “1” in order to control the frequency of the high frequency power (see Patent Document 1).

JP 2002-272134 A

  However, the contactless power supply device described in Patent Document 1 has a problem in that the intensity of the radiated electric field increases because the magnetic field generated from the coil increases. Therefore, when a structural member that reduces the magnetic field to suppress the radiated electric field intensity is provided, there is a problem that the apparatus itself is enlarged although the radiated electric field intensity can be suppressed.

  The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to provide a non-contact power feeding apparatus capable of preventing an increase in size while suppressing a radiated electric field intensity and a control thereof. It is to provide a method.

  In order to solve the above-described problem, the non-contact power feeding device of the present invention includes at least a power feeding side circuit having a first coil and a power receiving side circuit having a second coil, and the power feeding side circuit and the power receiving side circuit. In between, power transmission and reception (power transmission or reception) in a contactless manner by magnetic coupling, and at the time of power transmission and reception, the magnetic pole direction of the first coil is the same direction as the magnetic pole direction of the second coil, The power supply side circuit includes drive means for driving the inverter to generate high-frequency power to be supplied to the first coil, the drive means being higher than the resonance frequency of the power reception side circuit, and the first coil and the second coil. The combined ampere turn is selected to select a frequency within a range smaller than the combined ampere turn at the resonance frequency of the power receiving side circuit, and the inverter is driven.

  In the non-contact power supply device of the present invention, the power receiving side circuit includes: a power detection unit that detects power supplied to a load to be charged; and a command value calculation unit that calculates a command value of power supplied to the load. In addition, the drive means selects a frequency at which the combined ampere turn of the first coil and the second coil is minimum, and the power command value calculated by the command value calculation means is the power detected by the power detection means. It is preferable to determine at least one of the duty ratio and the step-up ratio so that

  In the non-contact power feeding device of the present invention, the phase difference between the current of the first coil and the current of the second coil is preferably greater than 90 degrees.

  The method for controlling a non-contact power feeding device of the present invention includes at least a power feeding side circuit having a first coil and a power receiving side circuit having a second coil, and a magnetic field between the power feeding side circuit and the power receiving side circuit. A method for controlling a non-contact power feeding device in which electric power is transmitted or received in a contactless manner by mechanical coupling, and the magnetic pole direction of the first coil is the same as the magnetic pole direction of the second coil during power transmission and reception. A drive step of driving the inverter to generate high-frequency power to be supplied to the power source, wherein in the drive step, the combined ampere turn of the first coil and the second coil is higher than the resonance frequency of the power receiving side circuit. The inverter is driven by selecting a frequency within a range smaller than the combined ampere turn at the resonance frequency of the circuit.

  The combined ampere turn is a concept including a combined current obtained by removing the concept of the number of turns from the combined ampere turn.

FIG. 1 is a configuration diagram illustrating a contactless power supply device according to the first embodiment. FIG. 2 is a schematic diagram showing a magnetic field generated when the first coil and the second coil are disk-type coils. FIG. 3 is a schematic diagram showing a magnetic field generated when the first coil and the second coil are solenoid coils. FIG. 4 is a diagram showing the correlation between the drive frequency of the inverter and the combined ampere turn in the disk type coil when the load power is constant. FIG. 5 is a diagram showing the correlation between the drive frequency of the inverter and the combined ampere turn in the solenoid coil when the load power is constant. FIG. 6 is a diagram illustrating how the driving frequency is selected by the driving frequency selection unit in the non-contact power feeding apparatus according to the first embodiment. 7 (a), 7 (b), and 7 (c) are waveform diagrams showing the magnetic flux due to the current flowing through the coil, FIG. 7 (a) shows the first example, and FIG. 7 (b) A second example is shown, and FIG. 7C shows a third example. FIG. 8 is a flowchart illustrating a method for controlling the non-contact power feeding apparatus according to the first embodiment. FIG. 9 is a configuration diagram illustrating the non-contact power feeding device according to the second embodiment. FIGS. 10A and 10B are diagrams for explaining an adjustment method based on the duty ratio according to the second embodiment. FIG. 10A shows before adjustment, and FIG. 10B shows after adjustment. Is shown. FIG. 11 is a flowchart illustrating a method for controlling the non-contact power feeding apparatus according to the second embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating a contactless power supply device according to the first embodiment. As shown in FIG. 1, the non-contact power feeding device 1 is used for charging a load 24 mounted on a vehicle, for example, and includes a power feeding side circuit 10 and a power receiving side circuit 20. When the non-contact power feeding device 1 is used for charging a vehicle battery (an example of the load 24), the power feeding side circuit 10 is provided on the ground side, and the power receiving side circuit 20 is provided on the vehicle side.

The power feeding side circuit 10 transmits high frequency power to the power receiving side circuit 20, and includes a commercial power source 11, a rectifying unit 12, a power factor improving boosting unit 13, an inverter 14, and a first capacitor C _1. When, and a first and a coil _{L 1.}

The commercial power supply 11 is a 50 Hz or 60 Hz AC power supply. The rectifying unit 12 rectifies the AC voltage 12 from the commercial power supply 11. The power factor improving step-up unit 13 is a step-up type PFC circuit. By switching the switching element S ₀ , generation of harmonic current due to the alternating current rectified by the rectifying unit 12 is suppressed, and the power factor is increased to “ 1 ".

The inverter 14 includes a smoothing capacitor and switching elements S _{1 to} S ₄ , and generates high-frequency AC power by switching the switching elements S _{1 to} S ₄ . Here, so that the generated high-frequency current is supplied to the resonance circuit composed of the first capacitor C ₁ and the first coil L ₁ Tokyo. The first capacitor C ₁ and the first coil L ₁ are connected in series, but not limited thereto, and may be connected in parallel. Resonant circuit first capacitor C ₁ and consists of the first coil L ₁ Tokyo forms an LC circuit.

The power receiving side circuit 20 from the power supply side circuit 10 be one that receiving the high-frequency power, and the second coil _{L 2,} a second capacitor _{C 2,} a rectifying unit 21, a filter unit 22, a relay 23, a load 24.

The second coil L ₂ receives high-frequency power from the first coil L ₁ by electromagnetic induction (magnetic coupling), and constitutes a resonance circuit together with the second capacitor C ₂ . Incidentally, the second capacitor C ₂ and the second coil L ₂ are connected in series, but not limited thereto, and may be connected in parallel. Resonant circuit and the second capacitor C ₂ and a second coil L ₂ Metropolitan forms an LC circuit has a resonant frequency omega _1.

That is, the first coil L ₁ and the second coil L ₂ is configured to transmitting and receiving electric power (transmission or receiving) in a non-contact by the magnetic coupling.

  The rectifier 21 is a rectifier circuit that rectifies high-frequency power from the resonance circuit into direct current. The filter 22 is configured by a smoothing capacitor that suppresses voltage fluctuation. The relay 23 is configured by a relay switch that can be switched on and off. The load 24 is a battery and is to be charged.

  Furthermore, as shown in FIG. 1, the power receiving circuit 20 includes a controller 25. The controller 25 includes a load power detection unit (power detection unit) 25a, a load control unit (command value calculation unit) 25b, and a coupling coefficient detection unit 25c. The load power detector 25a detects the power supplied to the load 24 to be charged. The load control unit 25b calculates a command value of power supplied to the load 24.

Coupling coefficient detection unit 25c detects a coupling coefficient k representing the degree of binding of the magnetic coupling of the first coil L ₁ and the second coil L _2. The coupling coefficient detection unit 25c can be obtained from, for example, an induced voltage on the power receiving side circuit 20 generated when the relay 23 is opened and a current is supplied only to the power feeding side circuit 10. A method for detecting the coupling coefficient k is as follows. It is not limited to this.

  Note that the controller 25 may be equipped with the above functions in one control unit, or may be distributed and installed in a plurality of control units. For example, a battery control unit that controls a battery as the load 24 includes a load power detection unit 25a and a load control unit 25b, and controls wireless communication between the power supply side circuit 10 and the power reception side circuit 20 or a battery control unit. A coupling coefficient detection unit 25c may be provided in the non-contact power supply control unit that performs communication with the communication unit.

Further, the power supply side circuit 10 includes a power control unit (drive means) 15. The power control unit 15 is for driving the inverter 14 to generate a high-frequency power supplied to the first coil L _1, a duty generation unit 15a, a driving frequency selector 15b, and a pulse generator 15c I have.

The duty generation unit 15a generates a duty ratio such that the current power P _out detected by the load power detection unit 25a becomes the command value P _{ref of the} power detected by the load control unit 25b. PI control (control combining proportional action and integral action) is performed. Therefore, information on the current power P _out detected by the load power detection unit 25a and information on the command value P _ref of the power detected by the load control unit 25b are input to the duty generation unit 15a.

The drive frequency selection unit 15 b generates a drive frequency for the inverter 14. Driving frequency selector 15b, the duty generation unit 15a, the information of the load power of the current detected by the detection section 25a power _{P out,} and power information of the command value _{P ref} of which is detected by the load control unit 25b, coupled Information on the coupling coefficient k detected by the coefficient detection unit 25c is input.

The pulse generation unit 15c generates a pulse having the frequency generated by the drive frequency selection unit 15b and the duty ratio generated by the duty generation unit 15a. The switching elements S _{1 to} S ₄ of the inverter 14 are driven by this pulse.

In particular, in the non-contact power feeding device 1 according to the first embodiment, the first coil L ₁ and the second coil L ₂ are disk-type coils, and the drive frequency selection unit 15 b is based on the resonance frequency of the power receiving side circuit 20. It is high, and the first synthesis ampere turns of the coil L ₁ and the second coil L ₂ selects a frequency in the range smaller than the synthetic ampere-turns at the resonant frequency of the power receiving side circuit 20. Thereby, in 1st Embodiment, enlargement can be prevented, suppressing radiation electric field strength. Hereinafter, this point will be described in detail.

2, the first coil L ₁ and the second coil L ₂ is a schematic diagram illustrating a magnetic field generated when a disk-type coil. The first winding directions of the coil L ₁ and the second coil L ₂ in FIG. 2 are the same. In FIG. 2, the load 24 is indicated as a resistance _RL for convenience.

First, the disk type coil is _one in which the axial directions of the coils L ₁ and L ₂ are the vehicle vertical direction (vertical direction) as shown in FIG. In this case, the magnetic field is as follows during power transmission / reception. In other words, it is assumed that when the AC voltage V ₁ is applied to the power supply side circuit 10, the voltage e ₁ and the current I ₁ are generated in the first coil L ₁ . Further, in the power receiving side circuit 20, the voltage e ₂ and the current I ₂ are generated in the second coil L ₂ based on the relational expression e ₁ · I ₁ = e ₂ · I ₂ . Note that, in the orientation shown in FIG. 2 to define _{e 1, e 2, I 1} , I 2 orientations.

At this time, the magnetic flux φ ₁ is generated in the first coil L ₁ . As is apparent from the flux phi _1, the first end of the coil L ₁ corresponds to the N pole as referred by a magnet (upper side in FIG. 2), the first end of the coil L ₁ (lower side in FIG. 2) Corresponds to the S pole in terms of a magnet.

Similarly, a magnetic flux φ ₂ is generated in the second coil L ₂ . As is apparent from this magnetic flux φ ₂ , one end of the second coil L ₂ (upper side in FIG. 2) corresponds to the N pole in terms of a magnet, and the other end of the second coil L ₂ (lower side in FIG. 2). Corresponds to the S pole in terms of a magnet.

Therefore, the magnetic pole direction of the first coil L ₁ and the second coil L ₂ in the example shown in FIG. 2 has the same orientation. Then, the whole of the magnetic flux phi _Total in the example shown in FIG. 2, the _{φ Total = φ 1 + φ 2} .

That is, as shown in FIG. 2, when the axial direction of the first coil L ₁ and the second coil L ₂ is the vehicle vertical direction (vertical direction), the magnetic flux φ ₁ generated in the first coil L ₁ . And the magnetic flux φ ₂ generated in the second coil L ₂ have the same direction, and the total magnetic flux φ _Total is the sum of the magnetic fluxes φ ₁ and φ ₂ . In FIG. 2, φ _m is a combined magnetic flux of magnetic fluxes φ ₁ and φ ₂ .

3, the first coil L ₁ and the second coil L ₂ is a schematic diagram illustrating a magnetic field generated when a solenoid coil. The first winding directions of the coil L ₁ and the second coil L ₂ in FIG. 3 are the same. In FIG. 3, the load 24 is indicated as a resistance _RL for convenience.

In the solenoid type coil, as shown in FIG. 3, the axial directions of the coils L ₁ and L ₂ are the vehicle plane direction (horizontal direction). In this case, the magnetic field is as follows during power transmission / reception. In other words, it is assumed that when the AC voltage V ₁ is applied to the power supply side circuit 10, the voltage e ₁ and the current I ₁ are generated in the first coil L ₁ . Further, in the power receiving side circuit 20, the voltage e ₂ and the current I ₂ are generated in the second coil L ₂ based on the relational expression e ₁ · I ₁ = e ₂ · I ₂ . Note that, in the orientation shown in FIG. 3 to define _{e 1, e 2, I 1} , I 2 orientations.

At this time, the magnetic flux φ ₁ is generated in the first coil L ₁ . As is apparent from the flux phi _1, the first end of the coil L ₁ (right side in FIG. 3) corresponds to the N pole as referred in the magnet, the first end of the coil L ₁ (left side in FIG. 3) is This corresponds to the S pole in terms of a magnet.

Similarly, a magnetic flux φ ₂ is generated in the second coil L ₂ . As is apparent from this magnetic flux φ ₂ , one end of the second coil L ₂ (right side in FIG. 3) corresponds to the S pole in terms of a magnet, and the other end (left side in FIG. 3) of the second coil L ₂ . This corresponds to the N pole in terms of a magnet.

Therefore, the magnetic pole direction of the first coil L ₁ and the second coil L ₂ in the example shown in FIG. 3 has a reverse orientation. Then, the whole of the magnetic flux phi _Total in the example shown in FIG. 3, the φ _Total = φ ₁ -φ _2.

That is, as shown in FIG. 3, when the axial direction of the first coil L ₁ and the second coil L ₂ is the vehicle plane direction (horizontal direction), the magnetic flux φ ₁ generated in the first coil L ₁ . The magnetic flux φ ₂ generated in the second coil L ₂ is in the opposite direction, and the total magnetic flux φ _Total is obtained by subtracting the magnetic flux φ ₂ from the magnetic flux φ ₁ . In FIG. 3, φ _m is a combined magnetic flux of magnetic fluxes φ ₁ and φ ₂ .

Then, radio wave magnitude (radiation field intensity) depends on the magnitude of the first magnetic flux of the coil L ₁ and the second coil L _2. Here, the magnitude B of the magnetic flux can be expressed by the following formula 1 in the arrangement of the disk-type coil in FIG. 1 and can be expressed by the following formula 2 in the arrangement of the solenoid-type coil in FIG.

In Equations 1 and 2, N ₁ is the number of turns of the first coil L ₁ , and D ₁ is the inner area of the first coil L ₁ . N ₂ is the number of turns of the second coil L ₂ , and D ₂ is the inner area of the second coil L ₂ . Furthermore, X is a first coil L ₁ and the second coil L _2, the distance between the position for measuring the magnetic flux density. Here, in order to consider the magnitude of the radio wave at a position away from the coil, X is sufficiently larger than the distance between the first coil L1 and the second coil L2, and Equations 1 and 2 are It is established approximately.

When the area _D 1, _{D 2} is assumed to be fixed, the magnetic flux B, the first number of turns of the coil _{L 1} and the second coil _{L 2 N} 1, and _{N 2,} the first coil _{L 1} and the second coil _{L 2} Depends on the currents I ₁ and I ₂ flowing through the current.

According to the configuration shown in FIGS. 1, 2, and 3, in the power receiving side circuit 20, it can be seen that the relationship shown in the following Equation 3 is established for the voltage.

In Equation 3, L ₂ is the inductance of the second coil L ₂ , and ω is the drive frequency of the inverter 14. C ₂ is the capacity of the second capacitor C ₂ . M represents the first coil L ₁ and the second mutual inductance of the coil L _2, a number that varies depending on the coupling coefficient k. In particular, the mutual inductance M has a positive value corresponding to the magnetic pole direction being the same direction in the disk type coil of FIG. 2, and the magnetic pole direction is corresponding to the opposite direction in the solenoid type coil of FIG. Thus, the mutual inductance M becomes a negative value.

The resonance frequency ω ₁ of the resonance circuit composed of the second capacitor C ₂ and the second coil L ₂ is the reciprocal of the square root of the product of the inductance of the second coil L ₂ and the capacitance of the second capacitor C ₂ .

The relationship between the currents I ₁ and I ₂ is expressed by Equation 3. Therefore, by using Equation 3, the combined ampere turn SAT of the first coil L ₁ and the second coil L ₂ determined from the number of turns N ₁ , N ₂ and the currents I ₁ , I ₂ is the disk type coil. It can be expressed by the following expression 4, and can be expressed by the following expression 5 in the solenoid type coil. In the following formulas 4 and 5, V ₂ represents the voltage of the load 24, and there is a relationship of V ₂ = R _L · I _{2 according to} Ohm's law.

FIG. 4 is a diagram showing the correlation between the drive frequency of the inverter 14 and the combined ampere turn SAT in the disk type coil when the load power is constant. As is clear from Equations 1 and 4, the smaller the synthetic ampere turn SAT, the smaller the magnetic flux B, and the radiated electric field intensity can be suppressed. As shown in FIG. 4, the present inventors have found that in the case of a disk-type coil, the combined ampere turn SAT becomes small at a frequency higher than the resonance frequency ω ₁ of the power receiving side circuit 20 that is a known value. . Thus, even if the load power is constant, the optimum combined ampere turn SAT can be obtained depending on the frequency.

FIG. 5 is a diagram showing the correlation between the drive frequency of the inverter 14 and the combined ampere turn SAT in the solenoid coil when the load power is constant. As is clear from Equations 2 and 5, the smaller the synthetic ampere turn SAT, the smaller the magnetic flux B, and the radiated electric field intensity can be suppressed. As shown in FIG. 5, the present inventors have found that in the case of a solenoid type coil, the combined ampere turn SAT becomes small at a frequency lower than the resonance frequency ω ₁ of the power receiving side circuit 20 that is a known value. . Thus, even if the load power is constant, the optimum combined ampere turn SAT can be obtained depending on the frequency.

Therefore, since the contactless power supply device 1 according to the first embodiment is a disk-type coil in which the axial directions of the coils L ₁ and L ₂ are the vehicle vertical direction (vertical direction), the drive frequency selection unit 15b includes a power receiving side circuit. A frequency higher than the resonance frequency ω _{1 of} 20 is selected, and the inverter 14 is driven at this frequency. FIG. 6 is a diagram illustrating how the driving frequency is selected by the driving frequency selection unit in the non-contact power feeding apparatus according to the first embodiment. In particular, FIG. 6 shows the relationship between the power supplied to the load 24 and the frequency.

The second coil L ₂ is, while receiving a high-frequency power by electromagnetic induction between the first coil L _1, and magnetic coupling occurs between the first coil L ₁ and the second coil L ₂ Yes. The relationship between the frequency and the power supplied to the load 24 is determined depending on the configuration of the power supply side circuit 10 and the power reception side circuit 20 and the magnitude of the resistance _RL of the load 24 and the magnitude of the mutual inductance M. Generally, two peaks appear in the graph representing the relationship between the frequency and the power supplied to the load 24 as shown in FIG.

Therefore, as shown in FIG. 6, there are four frequencies ω _{2 to} ω ₅ that satisfy the command value P _ref . In case the current is the current frequency of the power _{P out} is _{f ref,} the driving frequency selector 15b, will lower the sequential frequency, frequency and current power _{P out} shown in FIG. 6 and the command value _{P ref} matches ω ₄ or ω ₅ is selected. Note that the frequencies ω ₂ and ω ₃ are frequencies below the resonance frequency ω ₁ , and the combined ampere turn SAT becomes large, and the magnetic flux B cannot be kept small. Therefore, the frequencies ω ₂ and ω ₃ are not selected.

  Then, the pulse generation unit 15c generates a pulse corresponding to the frequency selected by the drive frequency selection unit 15b as described above, and drives the inverter 14.

Here, the number of turns N ₁ and N ₂ of the first coil L ₁ and the second coil L ₂ is also made the same number in advance, thereby simplifying Equation 4 as follows. The combined current SA (the value obtained by dividing the combined ampere turn SAT by the number of turns) when the number of turns N ₁ and N _{2 of} the first coil L ₁ and the second coil L ₂ is the same number can be expressed by the following Equation 6. it can.

As described above, when the number of turns N ₁ and N _{2 of} the first coil L ₁ and the second coil L ₂ are the same, the combined current SA can be reduced as apparent from the above formulas 1 and 6. The more the magnetic flux B becomes, the more the radiation electric field intensity can be suppressed. Further, the combined current SA shows the same frequency dependency as the combined ampere turn SAT shown in FIG. 4, and the combined current SA becomes smaller at a frequency higher than the resonance frequency ω ₁ of the power receiving side circuit 20 which is a known value. . Therefore, when the number of turns N ₁ and N ₂ are the same, the drive frequency selection unit 15b according to the first embodiment selects a frequency higher than the resonance frequency ω ₁ of the power receiving side circuit 20 based on the combined current SA. The inverter 14 may be driven at this frequency.

In the above and the following description, since the combined current SA is obtained by removing the concept of the number of turns N ₁ and N _{2 from} the combined ampere turn SAT, it is assumed that it is a kind of combined ampere turn SAT, and the combined ampere turn SAT. It shall be included in the concept of

Furthermore, as shown in FIG. 4, the inventors of the present invention, when the frequency is too high in the frequency range higher than the resonance frequency ω ₁ of the power receiving side circuit 20, causes the combined ampere turn SAT to change to the resonance frequency ω _{1 of the power} receiving side circuit 20. It has been found that it is larger than the synthetic ampere turn AT1 at the time. It has also been found that the frequency that is greater than the combined ampere turn AT1 at the resonance frequency ω ₁ of the power receiving side circuit 20 differs depending on the coupling coefficient k. For this reason, by selecting a frequency smaller than the combined ampere turn AT1 at the resonance frequency ω ₁ of the power receiving circuit 20 based on the coupling coefficient k, the radiation electric field strength can be more reliably reduced.

More specifically, as shown in FIG. 4, when the coupling coefficient k is 0.2, the combined ampere turn SAT tends to decrease when it becomes higher than the resonance frequency ω ₁ , and reaches a minimum value at the frequency ω ₆ . Become. Further, when the frequency is increased, the combined ampere turn SAT becomes the same value as the resonance frequency ω ₁ at the frequency ω ₇ . Thereafter, as the frequency increases, the combined ampere turn SAT further increases.

Therefore, the driving frequency selector 15b in the first embodiment, if the engagement factor k is 0.2, the driving frequency of the inverter 14 is greater than omega _1, to be smaller than omega ₇ (omega ₁ < a driving frequency <ω ₇ of the inverter 14). Thereby, the non-contact electric power feeder 1 which concerns on 1st Embodiment is trying to reduce a radiation electric field intensity | strength more reliably.

Furthermore, the power control unit 15, in order to suppress the more radiation field intensity, and a first current coil L ₁ the phase difference between the second current coil L ₂ is to be greater than 90 degrees. The power control unit 15 in more detail is the first current coil L ₁ the phase difference between the second current coil L ₂ and to be smaller than the larger 270 ° than 90 °.

FIG. 7A, FIG. 7B, and FIG. 7C are waveform diagrams showing magnetic fluxes due to currents flowing through the coils L ₁ and L ₂ , and FIG. 7A shows a first example. FIG. 7B shows a second example, and FIG. 7C shows a third example. As shown in FIG. 7 (a), when the current phase is close to the same phase, the total magnetic flux phi _Total there reinforce each other and the magnetic field _{B 2} by the magnetic field _{B 1} and the second coil _{L 2} by the first coil _{L 1} is greater turn into. On the other hand, by making the phase difference larger than 90 degrees and smaller than 270 degrees, both magnetic fluxes B ₁ and B ₂ can be made to cancel each other as shown in FIG. The overall magnetic flux φ _Total can be reduced to suppress the radiation electric field strength. The phase difference can be set by adjusting the impedance or frequency on the power receiving side circuit 20 side.

As shown in FIG. 7C, when the difference between the amplitudes is large, the effect of canceling the magnetic fluxes B ₁ and B ₂ with each other is small even with the above phase difference. For this reason, in the first embodiment, the power control unit 15 preferably adjusts the mutual amplitude. In that respect, the combined ampere turn SAT is an evaluation index composed of an amplitude difference and a phase difference between the currents flowing through the coils L ₁ and L ₂ , and if a frequency that reduces the combined ampere turn SAT is selected, the amplitude is individually determined. Even if the phase is not adjusted, the amplitude and phase are optimized as a whole.

Next, the control method of the non-contact electric power feeder 1 which concerns on 1st Embodiment is demonstrated. FIG. 8 is a flowchart illustrating a method for controlling the non-contact power feeding device 1 according to the first embodiment. As shown in FIG. 8, first, the power control unit 15 inputs the current power P _out detected by the load power detection unit 25a and the command value P _ref calculated by the load control unit 25b (step S101).

Next, the power control unit 15 inputs the coupling coefficient k detected by the coupling coefficient detection unit 25c (step S102). Thereafter, the duty generation unit 15a of the power control unit 15 determines the duty ratio from the current power P _out detected by the load power detection unit 25a and the command value P _ref calculated by the load control unit 25b (step). S103).

Next, the drive frequency selection unit 15b of the power control unit 15 selects the drive frequency of the inverter 14 (step S104). At this time, as shown in the theory described above, the drive frequency selection unit 15b is higher than the resonance frequency ω ₁ of the power receiving side circuit 20 and the combined ampere turn SAT is at the resonance frequency ω ₁ of the power receiving side circuit 20. A frequency within a range smaller than the combined ampere turn AT1 is selected. More specifically, the drive frequency selection unit 15b determines the upper limit value of the frequency from the coupling coefficient k input in step S102. For example, as shown in FIG. 4, when the coupling coefficient k is 0.2, the upper limit value is omega _7. The drive frequency selection unit 15b sequentially decreases the frequency from the upper limit value, for example, and selects a frequency that _satisfies P _ref = P _{out in a} range where the frequency does not become the resonance frequency ω ₁ or less.

Then, the pulse generation unit 15c of the power control unit 15 generates a pulse from the frequency selected by the duty ratio and the step S104 determined in step S103, switching the switching element S ₁ to S ₄ by the pulse Thus, the inverter 14 is driven (step S105). As a result, as described with reference to the above formulas 1, 4, and 6, the radiation field strength can be suppressed.

  Thereafter, the contactless power supply device 1 determines whether or not charging is complete (step S106). At this time, the contactless power supply device 1 determines that charging is complete when the remaining capacity of the battery as the load 24 exceeds a predetermined value.

  If it is determined that charging has not been completed (step S106: NO), the process proceeds to step S101. On the other hand, when it is determined that the charging is completed (step S106: YES), the process shown in FIG. 8 ends.

In this way, according to the non-contact power feeding apparatus 1 that transmits and receives power (power transmission or reception) in a contactless manner by magnetic coupling between the power feeding side circuit 10 and the power receiving side circuit 20, and the control method thereof, the frequency Thus, the composite ampere turn SAT can be reduced, and the radiation electric field strength can be reduced without using structural members as much as possible. Present inventors in detail, depending on the current magnitude of the wave flows through the first turn number N ₁ of the coil L ₁ and the second coil L _2, N ₂ and their, the number of turns N _1, N ₂ and the current of determined from the size, the first coil L ₁ and the second synthetic ampere turns SAT of the coil L ₂ is, when the disk-type coil (the first coil L ₁ and the second magnetic pole direction same direction of the coil L _2), receiving It has been found that the frequency becomes smaller at a frequency higher than the resonance frequency ω ₁ of the side circuit 20. Further, in the case of a disk-type coil, the inventors of the present invention have a combined ampere-turn SAT at a resonance frequency ω ₁ of the power receiving side circuit 20 when the frequency is too high in a frequency range higher than the resonance frequency ω ₁ of the power receiving side circuit 20. It was found to be larger than the synthetic ampere turn SAT in Therefore, the combined ampere turn SAT of the first coil L ₁ and the second coil L ₂ is higher than the resonance frequency ω ₁ of the power receiving side circuit 20, and the resonance frequency ω _{1 of the power} receiving side circuit 20. By selecting a frequency within a range smaller than the combined ampere turn SAT at the time, the radiation electric field strength can be reduced. Further, the reduction of the radiation electric field intensity can be realized by selecting the frequency without using a structural member for reducing the magnetic field as much as possible. Therefore, enlargement can be prevented while suppressing the radiation electric field intensity.

Further, since the first current coil L ₁ is the phase difference between the second current coil L ₂ greater than 90 degrees, it becomes possible to cancel the magnetic flux generated by each other, it can be reduced even more radiated emission.

  Next, a second embodiment of the present invention will be described. The non-contact power feeding device and the control method thereof according to the second embodiment are the same as those of the first embodiment, but the configuration and processing contents are partially different. Hereinafter, differences from the first embodiment will be described.

  FIG. 9 is a configuration diagram showing the non-contact power feeding device 2 according to the second embodiment. As shown in FIG. 9, in the non-contact power feeding device 2 according to the second embodiment, the drive frequency selection unit 15b selects a frequency based on the coupling coefficient k from the coupling coefficient detection unit 25c. Specifically, the drive frequency selection unit 15b stores a map showing the correspondence between the coupling coefficient k and the frequency as shown in FIG. 9, and when the coupling coefficient k from the coupling coefficient detection unit 25c is input, the map is displayed. Refer to to determine the frequency.

  Here, the frequency selected by the drive frequency selector 15b is a frequency at which the combined ampere turn SAT shown in FIG. 4 is minimized. Therefore, the radiation electric field intensity can be suppressed to the maximum.

Further, the drive frequency selection unit 15b may store the following Expression 7 or 8 instead of the map.

The above Equation 7 is an equation for determining the frequency at which the combined ampere turn SAT is minimum when the resistance _{RL of the} load 24 is zero. Expression 8 is an expression for determining a frequency at which the combined current SA is minimized when the number of turns N ₁ and N ₂ are the same. Here, when the resistance _RL is not 0, Equations 7 and 8 are corrected in consideration of the load 24. Also in this case, the frequency that minimizes the combined ampere-turn SAT and the combined current SA can be similarly determined by the corrected mathematical formula.

That is, since the driving frequency selector 15b, the coupling coefficient k calculated mutual inductance M, it is possible to further determine the resistance R _L of the load power detecting unit of the current detected by 25a power P _out of such a load information 24, The frequency that minimizes the combined ampere-turn SAT and the combined current SA can be determined by the above formula.

Here, in the second embodiment, since the frequency is uniquely determined by the coupling coefficient k, there is a possibility of hindering the control to set P _out = P _ref . Therefore, in the second embodiment, P _out = P _ref is realized by controlling the duty ratio.

  FIG. 10A and FIG. 10B are diagrams for explaining the adjustment method based on the duty ratio according to the second embodiment, and show the relationship between the frequency and the power supplied to the load 24. 10A shows the relationship between the frequency before adjustment and the power supplied to the load 24, and FIG. 10B shows the relationship between the frequency after adjustment and the power supplied to the load 24. Yes.

As shown in FIG. 10A, when the frequency at which the combined ampere turn SAT is minimum is ω ₆ , P _out > P _ref is satisfied. Therefore, the duty generation unit 15a decreases the duty ratio. As a result, as shown in FIG. 10B, the output power is shifted downward in the figure, and P _out = P _ref is realized at the frequency ω ₆ .

In FIG. 10, the case where the duty ratio is decreased is described as an example. However, when P _out <P _{ref at the} frequency at which the combined ampere turn SAT is minimum, the duty ratio is increased. .

Furthermore, in the second embodiment, P _out = P _ref is realized at a frequency at which the combined ampere turn SAT is minimized by controlling the duty ratio by driving the switching elements S _{1 to} S ₄ of the inverter 14. but not limited thereto, may be changed to step-up ratio of the switching elements S ₀ of the power factor improving step-up unit 13 calculates a duty ratio. This is also because P _out = P _ref can be realized at a frequency at which the combined ampere turn SAT is minimized, similarly to the duty ratio control.

  Next, a method for controlling the non-contact power feeding device 2 according to the second embodiment will be described. FIG. 11 is a flowchart illustrating a method for controlling the non-contact power feeding device 1 according to the second embodiment. In addition, the same code | symbol is attached | subjected to the process same as the process shown in FIG. 8, and description is abbreviate | omitted.

After inputting the coupling coefficient k (after step S102), the drive frequency selection unit 15b reads from the map or Formula 7 or Formula 8 (or Formula 7 or Formula 8 after being corrected in consideration of the load 24). The frequency that minimizes the combined ampere turn SAT is selected (step S107). Next, the duty control unit 15a selects the duty ratio (and the boost ratio) so that P _out = P _ref at the frequency selected in step S107 (step S108).

  Thereafter, processing similar to that in steps S105 and S106 shown in FIG. 8 is executed, and the processing shown in FIG. 11 ends.

  In this way, according to the non-contact power feeding device 2 and the control method thereof according to the second embodiment, as in the first embodiment, an increase in size can be prevented while suppressing the radiated electric field strength, and the magnetic flux can be reduced. By canceling out, the radiation electric field strength can be further reduced.

Further, according to the non-contact power feeding device 2 and the control method thereof according to the second embodiment, the power control unit 15 that is a driving unit of the power feeding side circuit 10 selects a frequency that minimizes the combined ampere turn SAT. The radiation field intensity can be further reduced. Further, by selecting the smallest frequency, when no longer become the current power P _{out =} command value P _ref, the current power P _out detected by the load power detecting unit 25a is a power detection means, In order to determine and adjust at least one of the duty ratio and the boost ratio so as to match the command value _Pref of the power calculated by the load control unit 25b which is the command value calculation means, at least the duty ratio and the boost ratio By adjusting one ratio, it is possible to make the current power P _out = command value P _ref . Therefore, the radiation electric field strength can be further reduced without affecting the charging power.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, You may add a change in the range which does not deviate from the meaning of this invention, and combines each embodiment. Also good.

  For example, the contactless power feeding devices 1 and 2 according to the above-described embodiment are not limited to the illustrated circuit configuration, and various modifications are possible, for example, the power feeding side circuit 10 includes an insulating transformer.

  Further, in the above embodiment, the contactless power feeding devices 1 and 2 include the coupling coefficient detection unit 25c, but instead of this, data of the coupling coefficient k may be stored in advance. For example, when the non-contact power feeding devices 1 and 2 are used exclusively for a specific passenger car and the distance between the power feeding side circuit 10 and the power receiving side circuit 20 is already known, the power control unit 15 sends the data of the coupling coefficient k. You may make it memorize | store and select a frequency based on this coupling coefficient k.

  Further, when the non-contact power feeding devices 1 and 2 are used for charging the vehicle battery, since the distance between the power feeding side circuit 10 and the power receiving side circuit 20 based on the vehicle height can be predicted, the data of the coupling coefficient k is stored on the vehicle side. In addition, it may be configured to transmit to the power control unit 15 during charging.

  As mentioned above, although embodiment of this invention was described, these embodiment is only the illustration described in order to make an understanding of this invention easy, and this invention is not limited to the said embodiment. The technical scope of the present invention is not limited to the specific technical matters disclosed in the above embodiment, but includes various modifications, changes, alternative techniques, and the like that can be easily derived therefrom.

  This application is based on the priority based on Japanese Patent Application No. 2012-267742 filed on December 7, 2012 and on Japanese Patent Application No. 2013-084547 filed on April 15, 2013 All of the contents of the two applications are hereby incorporated by reference.

  According to the present invention, since the inverter is driven by selecting a frequency within the above range, the combined ampere turn can be reduced by selecting the frequency, and it is not necessary to provide a structural member, and the radiation electric field strength can be reduced. Therefore, enlargement can be prevented while suppressing the radiation electric field intensity.

DESCRIPTION OF SYMBOLS 1, 2 Non-contact electric power feeder 10 Power supply side circuit 11 Commercial power supply 12 Rectifier 13 Power factor improvement booster 14 Inverter 15 Electric power controller (drive means)
20 Power Receiving Side Circuit 21 Rectifier 22 Filter 23 Relay
24 load 25 battery controller 25a load power detection unit (power detection means)
25b Load control unit (command value calculation means)
25c coupling coefficient detector C ₁ first capacitor L ₁ first coil C ₂ second capacitor L ₂ second coil

Claims (4)

Having at least a power feeding side circuit having a first coil and a power receiving side circuit having a second coil;
Power is transmitted and received in a contactless manner by magnetic coupling between the power supply side circuit and the power reception side circuit, and the magnetic pole direction of the first coil is the same as the magnetic pole direction of the second coil during power transmission and reception. In the contactless power supply device
The power supply side circuit includes driving means for driving an inverter to generate high-frequency power to be supplied to the first coil,
The driving means is higher than a resonance frequency of the power receiving side circuit, and a combined ampere turn of the first coil and the second coil is smaller than a combined ampere turn at the resonance frequency of the power receiving side circuit. A non-contact power feeding apparatus, wherein a frequency within a range is selected to drive the inverter. The contactless power supply device according to claim 1,
The power receiving side circuit further includes power detection means for detecting power supplied to a load to be charged, and command value calculation means for calculating a command value of power supplied to the load,
The drive means selects a frequency at which a combined ampere turn of the first coil and the second coil is minimized, and the power detected by the power detection means is the power of the power calculated by the command value calculation means. A non-contact power feeding apparatus, wherein at least one ratio of a duty ratio and a step-up ratio is determined so as to match a command value. A contactless power supply device according to claim 1 or 2,
The non-contact power feeding apparatus according to claim 1, wherein a phase difference between the current of the first coil and the current of the second coil is greater than 90 degrees. At least a power feeding side circuit having a first coil and a power receiving side circuit having a second coil, and transmitting power in a contactless manner by magnetic coupling between the power feeding side circuit and the power receiving side circuit or In the control method of the non-contact power feeding device in which the magnetic pole direction of the first coil is the same direction as the magnetic pole direction of the second coil during power transmission and reception
A driving step of driving an inverter to generate high-frequency power to be supplied to the first coil;
In the driving step, the combined ampere turn of the first coil and the second coil is higher than the resonance frequency of the power receiving side circuit and smaller than the combined ampere turn at the resonance frequency of the power receiving side circuit. A method for controlling a non-contact power feeding device, wherein a frequency within a range is selected to drive the inverter.

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