JP6369792B2 - Non-contact power supply device and non-contact power supply system - Google Patents

Description

  The present invention relates to a non-contact power supply device and a non-contact power supply system, and more particularly to a non-contact power supply device and a non-contact power supply system that supply power to a load in a non-contact manner.

  Conventionally, a non-contact power supply device that supplies power to a vehicle such as an electric vehicle or a hybrid electric vehicle in a non-contact manner is provided (see, for example, Patent Document 1). The non-contact power feeding device described in Patent Literature 1 includes an inverter unit (inverter circuit), a power transmission antenna (primary side resonance unit), and a power transmission control unit.

  The inverter unit includes a full bridge type inverter circuit. This inverter circuit is composed of four field effect transistors. The inverter unit converts a DC voltage into an AC voltage having a predetermined frequency, and outputs the converted AC voltage to the power transmission antenna. The power transmission control unit controls the voltage value of the DC voltage input to the inverter unit and the frequency of the AC voltage output from the inverter unit.

  In this non-contact power feeding device, when the power receiving antenna mounted on the vehicle is arranged at a position facing the power transmitting antenna, AC power is transmitted from the power transmitting antenna to the power receiving antenna in a contactless manner due to a resonance phenomenon between the power transmitting antenna and the power receiving antenna. The In the vehicle, the AC power transmitted to the power receiving antenna is charged to the battery via a rectifier and a charger provided in the vehicle.

  By the way, in the non-contact electric power feeder of patent document 1 mentioned above, when the frequency characteristic of the inverter part changed, for example by ambient temperature changing, there existed a possibility that the operating frequency of an inverter part may enter into a phase advance area | region.

JP2013-211932A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a non-contact power supply device and a non-contact power supply system in which the operating frequency of the inverter circuit is difficult to enter the phase advance region.

  A contactless power supply device according to one embodiment of the present invention includes a primary-side resonance unit, an inverter circuit, and a control unit. The primary side resonance unit includes a primary side coil and a primary side capacitor. The inverter circuit converts DC power into AC power and outputs the AC power to the primary side resonance unit. The control unit operates the inverter circuit at a predetermined operating frequency. The control unit measures a physical quantity related to output power of the inverter circuit by changing the operating frequency within a specified range. When the difference between the physical quantity when the operating frequency is the lower limit value in the specified range and the physical quantity when the operating frequency is the upper limit value in the specified range is less than or equal to the specified value, A predetermined operation is performed so that the operating frequency does not enter the phase advance region.

  A contactless power feeding system according to one embodiment of the present invention includes the above-described contactless power feeding device and a contactless power receiving device. The contactless power receiving device receives power supplied from the contactless power feeding device. The non-contact power receiving device includes a secondary resonance unit. The secondary-side resonance unit includes a secondary-side coil and a secondary-side capacitor, and outputs electric power supplied to the load using electromagnetic coupling with the primary-side resonance unit.

It is a schematic circuit diagram which shows the non-contact electric power feeder and non-contact electric power feeding system which concern on one Embodiment of this invention. It is the schematic which shows the usage example of the non-contact electric power feeding system which concerns on one Embodiment of this invention. It is a figure which shows the frequency characteristic of the inverter circuit which concerns on one Embodiment of this invention. 4A to 4C are explanatory diagrams for explaining the operation of the non-contact power feeding device according to the embodiment of the present invention. It is a flowchart explaining operation | movement of the non-contact electric power supply which concerns on one Embodiment of this invention. It is a flowchart explaining operation | movement of the non-contact electric power feeder which concerns on the modification 1 of one Embodiment of this invention. FIG. 7A is a circuit diagram illustrating a primary side capacitor of the primary side resonance unit according to Modification 2 of the embodiment of the present invention. FIG. 7B is a circuit diagram illustrating a primary side coil of the primary side resonance unit according to the second modification of the embodiment of the present invention. It is a flowchart explaining operation | movement of the non-contact electric power feeder which concerns on the modification 3 of one Embodiment of this invention. It is a flowchart explaining operation | movement of the non-contact electric power feeder which concerns on the modification 4 of one Embodiment of this invention.

  A non-contact power supply device 2 and a non-contact power supply system 1 according to an embodiment of the present invention will be specifically described with reference to the drawings. However, the configuration described below is merely an example of the present invention, and the present invention is not limited to the following embodiment. Therefore, various modifications other than this embodiment can be made according to the design and the like as long as they do not depart from the technical idea of the present invention.

  As shown in FIG. 1, the contactless power supply system 1 of the present embodiment includes a contactless power supply device 2 and a contactless power receiving device 3. The non-contact power feeding device 2 includes an inverter circuit 21, a control unit 22, and a primary side resonance unit 23. The non-contact power feeding device 2 preferably further includes a DC power source 20 and a current detection unit 24.

  As shown in FIG. 1, the inverter circuit 21 includes a full bridge type inverter circuit. The inverter circuit includes four switching elements Q1 to Q4 made of, for example, an n-channel enhancement type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Switching elements Q1 to Q4 may be other semiconductor switching elements such as bipolar transistors and IGBTs (Insulated Gate Bipolar Transistors).

  In the inverter circuit 21, a series circuit of two switching elements Q1 and Q2 and a series circuit of two switching elements Q3 and Q4 are electrically connected in parallel. The drains of the switching elements Q1 and Q3 are electrically connected to the output terminal on the high potential side of the DC power supply 20, respectively. The sources of the switching elements Q2 and Q4 are electrically connected to the output terminal on the low potential side of the DC power supply 20, respectively.

  A connection point between the source of the switching element Q3 and the drain of the switching element Q4 is the first output terminal of the inverter circuit 21. A connection point between the source of the switching element Q1 and the drain of the switching element Q2 is the second output terminal of the inverter circuit 21.

  The switching elements Q1, Q4 are turned on / off by the first drive signal G1 output from the control unit 22. Further, the switching elements Q2, Q3 are turned on / off by the second drive signal G2 output from the control unit 22. The second drive signal G2 is a rectangular wave signal that is 180 degrees out of phase with the first drive signal G1.

  The inverter circuit 21 operates so as to alternately switch between the ON periods of the switching elements Q1 and Q4 and the ON periods of the switching elements Q2 and Q3 by the first drive signal G1 and the second drive signal G2. Thereby, the inverter circuit 21 converts the DC power supplied from the DC power supply 20 into AC power, and outputs the converted AC power to the primary side resonance unit 23.

  In the following, as shown in FIG. 1, the voltage input from the DC power supply 20 to the inverter circuit 21 is referred to as “input voltage V1”, and the current input from the DC power supply 20 to the inverter circuit 21 is referred to as “input current I1”. Also, as shown in FIG. 1, the voltage output from the inverter circuit 21 is referred to as “output voltage V2”, and the current output from the inverter circuit 21 is referred to as “output current I2”.

  The control unit 22 includes, for example, a microcomputer as a main configuration. The control unit 22 controls the inverter circuit 21 by outputting the first drive signal G1 and the second drive signal G2 to the switching elements Q1 to Q4 of the inverter circuit 21.

  The primary side resonance part 23 has the primary side coil L1 and the primary side capacitor | condenser C1. The primary side coil L1 is, for example, a spiral coil in which a conducting wire is wound in a spiral shape. The primary side capacitor C1 is electrically connected in series to the primary side coil L1. The primary side resonance section 23 forms a resonance circuit (primary side resonance circuit) with the primary side coil L1 and the primary side capacitor C1.

  The primary coil L1 generates a magnetic flux when an alternating current output from the inverter circuit 21 flows. That is, the primary coil L1 receives the AC power output from the inverter circuit 21 and generates a magnetic flux.

  The current detection unit 24 includes, for example, a shunt resistor and a Hall element. As shown in FIG. 1, the current detection unit 24 detects an input current I1 from the DC power supply 20 to the inverter circuit 21. The detection result (instantaneous current of the input current I1) of the current detection unit 24 is input to the control unit 22. Further, the input voltage V <b> 1 from the DC power supply 20 to the inverter circuit 21 is also input to the control unit 22. Therefore, the control unit 22 can obtain the input power P1 (instantaneous power) to the inverter circuit 21 from the input current I1 and the input voltage V1.

  In the non-contact power feeding system 1 of the present embodiment, the non-contact power feeding device 2 is installed on the floor or the ground as shown in FIG. The non-contact power feeding device 2 may be arranged not only on the floor or the ground but also embedded in the floor or the ground. Further, the non-contact power feeding device 2 is configured such that only the primary coil L1 is disposed at a position that can be opposed to the secondary coil L2, and other components, circuits, and the like are disposed away from the primary coil L1. May be.

  The non-contact power receiving device 3 includes a secondary side resonance unit 31 and a rectification unit 32.

  As shown in FIG. 1, the secondary side resonance unit 31 is configured by electrically connecting a secondary side coil L <b> 2 and a secondary side capacitor C <b> 2 in series to a pair of input ends of the rectification unit 32. The secondary coil L2 forms a resonance circuit (secondary resonance circuit) together with the secondary capacitor C2.

  The secondary coil L2 is a spiral type coil in which, for example, a conducting wire is wound in a spiral shape, like the primary coil L1. As shown in FIG. 2, the secondary coil L <b> 2 is disposed so as to be positioned in the vicinity of the primary coil L <b> 1 when the electric vehicle 100 stops at a predetermined stop position. In other words, when the electric vehicle 100 stops at a predetermined stop position, the secondary coil L2 is arranged to face the primary coil L1 with a predetermined interval.

  When the secondary coil L2 receives the magnetic flux generated by the primary coil L1, an alternating current flows by electromagnetic induction. That is, the secondary coil L2 receives the magnetic flux generated by the primary coil L1 and generates AC power.

  As shown in FIG. 1, the rectifying unit 32 includes a diode bridge 321 and a capacitor C3. The diode bridge 321 is composed of four diodes. The diode bridge 321 converts the alternating current generated in the secondary coil L2 into a pulsating current and outputs the pulsating current. The capacitor C3 is electrically connected to a pair of output terminals of the diode bridge 321, smoothes the pulsating current output from the diode bridge 321, and outputs a direct current.

  That is, the rectifier 32 rectifies the AC power generated in the secondary coil L2 into DC power and outputs the DC power. The DC power output from the rectifying unit 32 is supplied to the load 4 (in the present embodiment, the charging circuit 102).

  In the non-contact power feeding system 1 of the present embodiment, the non-contact power receiving device 3 is installed in the body of the electric vehicle 100 as shown in FIG. The non-contact power receiving device 3 is electrically connected to the storage battery 101 via the charging circuit 102. The storage battery 101 includes, for example, a nickel metal hydride battery, a lithium ion battery, a high-capacity capacitor, and the like. The storage battery 101 is used as a power source for an electric motor included in the electric vehicle 100.

  In the non-contact power feeding system 1 of the present embodiment, power is transmitted from the primary side resonance unit 23 to the secondary side resonance unit 31 by a resonance method using a magnetic resonance phenomenon. And in the non-contact electric power feeding system 1 of this embodiment, the non-contact electric power receiving apparatus 3 uses the magnetic resonance of the primary side resonance part 23 and the secondary side resonance part 31 efficiently for the output electric power of the non-contact electric power supply apparatus 2. Is transmitted to. Therefore, it is preferable that the frequency characteristic of the primary side resonance unit 23 and the frequency characteristic of the secondary side resonance unit 31 coincide with each other.

  Hereinafter, the frequency characteristics (hereinafter referred to as “resonance characteristics”) of the primary side resonance unit 23 in the non-contact power feeding system 1 of the present embodiment will be specifically described with reference to FIG.

  In the non-contact power feeding system 1 of the present embodiment, the resonance characteristics change according to the density of magnetic coupling between the primary side coil L1 and the secondary side coil L2. In other words, the resonance characteristics change according to the coupling coefficient between the primary side coil L1 and the secondary side coil L2. When the coupling coefficient is large to some extent, the resonance characteristics are so-called bimodal characteristics in which two local maximum values of the output of the primary side resonance unit 23 appear as shown in FIG.

  In this resonance characteristic, there is a peak where the output of the primary side resonance unit 23 becomes a maximum value at the first frequency fr1, and a valley where the output of the primary side resonance unit 23 becomes a minimum value at the second frequency fr2 (fr2> fr1). Appears. Further, in this resonance characteristic, there is a peak where the output of the primary side resonance unit 23 becomes a maximum value at the third frequency fr3 (fr3> fr2). That is, this resonance characteristic (bimodal characteristic) has two resonance frequencies (first frequency fr1 and third frequency fr3).

  Here, according to the correlation between the operating frequency f1 (for example, 85 ± 5 kHz) of the inverter circuit 21 and the frequencies fr1 to fr3, the inverter circuit 21 operates in either the slow phase mode or the fast phase mode. The “operating frequency f1” is the frequency of the first drive signal G1 and the second drive signal G2, in other words, the frequency of the output voltage V2 of the inverter circuit 21.

  The phase advance mode is a mode in which the inverter circuit 21 operates in a state where the phase of the output current I2 of the inverter circuit 21 is ahead of the phase of the output voltage V2 of the inverter circuit 21. In the phase advance mode, the switching operation of the inverter circuit 21 is so-called hard switching.

  The slow phase mode is a mode in which the inverter circuit 21 operates in a state where the phase of the output current I2 of the inverter circuit 21 is delayed from the phase of the output voltage V2 of the inverter circuit 21. In the slow phase mode, the switching operation of the inverter circuit 21 is so-called soft switching.

  In the slow phase mode, loss due to switching of the switching elements Q1 to Q4 can be reduced, and excessive electrical stress can be prevented from being applied to the switching elements Q1 to Q4. Therefore, in the non-contact power feeding device 2 of the present embodiment, it is preferable that the inverter circuit 21 operates in the slow phase mode.

  As shown in FIG. 3, the inverter circuit 21 includes a case where the operating frequency f1 is located in a frequency region between the first frequency fr1 and the second frequency fr2, and a frequency region where the operating frequency f1 is larger than the third frequency fr3. It operates in the slow phase mode in either case.

  Note that a frequency region between the first frequency fr1 and the second frequency fr2 and a frequency region larger than the third frequency fr3 are regions that operate in the slow phase mode, that is, the “slow phase region”. Further, a frequency region smaller than the first frequency fr1 and a frequency region between the second frequency fr2 and the third frequency fr3 are regions that operate in the fast phase mode, that is, the “fast phase region”.

  By the way, in the non-contact power feeding device 2 of the present embodiment, assuming that the operating frequency f1 of the inverter circuit 21 is a constant frequency, the frequency characteristics of the inverter circuit 21 change as the ambient temperature changes. There is a possibility that the frequency f1 enters the phase advance region.

  Therefore, in the contactless power supply device 2 of the present embodiment, a physical quantity related to the output power of the inverter circuit 21 is measured so that the operating frequency f1 becomes difficult to enter the phase advance region even when the frequency characteristic of the inverter circuit 21 changes. Then, a predetermined operation is performed based on the measurement result. In the following, the operation for increasing the operating frequency f1 of the inverter circuit 21 will be described as a predetermined operation.

  4A to 4C are diagrams showing the frequency characteristics of the inverter circuit 21, and particularly showing the relationship between the operating frequency f1 and the input power P1. Therefore, in this embodiment, the input power P1 to the inverter circuit 21 is obtained as a physical quantity related to the output power of the inverter circuit 21. FIG. 5 is a flowchart for explaining the operation of the control unit 22. Hereinafter, it demonstrates concretely, referring FIG. 4A-FIG. 4C and FIG.

  As described above, the inverter circuit 21 is preferably operated in the slow phase mode. Therefore, the operation frequency f1 of the inverter circuit 21 needs to be higher than the resonance frequency of the primary side resonance unit 23. Further, the operating frequency f1 of the inverter circuit 21 needs to be lower than the frequency at which the minimum power required to operate the load 4 is output.

  As shown in FIG. 4A, the control unit 22 sets the operating frequency f1 of the inverter circuit 21 to the frequency f11 and fluctuates the operating frequency f1 within a specified range including the frequency f11 (step S1 in FIG. 5). In the example shown in FIG. 4A, the control unit 22 varies the operating frequency f1 within the range of the frequency f11 ± Δf1 (for example, Δf1 = 1 kHz). Moreover, it is preferable to perform the operation | movement which fluctuates the operating frequency f1 with a sampling period of 100 Hz, for example.

  Next, the control unit 22 obtains the input power P1 at the lower limit value and the input power P1 at the upper limit value in the specified range, and obtains a difference ΔP1 between these input powers P1 (step S2 in FIG. 5). . In the example shown in FIG. 4A, the control unit 22 has a difference ΔP1 (= P11−P12) between the input power P11 at the frequency f12 (= f11−Δf1) and the input power P12 at the frequency f13 (= f11 + Δf1). Ask for.

  Then, the control unit 22 compares the difference ΔP1 with the preset specified value, and in the example shown in FIG. 4A, the difference ΔP1 is larger than the specified value, and thus the process proceeds to step S1 (in FIG. 5). NO in step S3). At this time, the inverter circuit 21 continues to operate at the initially set operating frequency f1 (= f11).

  By the way, when the ambient temperature changes, the frequency characteristic of the inverter circuit 21 changes from the broken line a1 to the solid line a2 as shown in FIG. 4B. Since the operating frequency f1 is the same frequency f11 as that in FIG. 4A, the difference ΔP1 between the input power P13 at the lower limit value (f1 = f12) and the input power P14 at the upper limit value (f1 = f13) in the above specified range (= P13-P14) is smaller than when the ambient temperature does not change.

  Then, when the difference ΔP1 is equal to or less than the specified value (YES in step S3 in FIG. 5), the control unit 22 increases the operating frequency f1 by α as shown in FIG. Step S4 in 5). This makes use of the fact that the difference ΔP1 of the input power P1 becomes smaller and approaches the phase advance region. In this case, the operating frequency f1 is increased so as to be away from the phase advance region. As a result, it is possible to make it harder for the operating frequency f1 to enter the phase advance region than when the operating frequency f1 of the inverter circuit 21 is kept constant.

  When the operating frequency f1 becomes higher than the frequency f11 by α, the difference ΔP1 (= P15) between the input power P15 at the lower limit value (f1 = f14) and the input power P16 at the upper limit value (f1 = f15) in the above specified range. -P16) is larger than when the operating frequency f1 is constant. And the control part 22 transfers to step S1 from step S3 since difference (DELTA) P1 is larger than said regulation value.

  In the above embodiment, the operating frequency f1 of the inverter circuit 21 is increased to make it difficult for the operating frequency f1 to enter the phase advance region, but the inverter circuit 21 may be stopped instead of increasing the operating frequency f1. That is, the operation for stopping the inverter circuit 21 may be a predetermined operation. Hereinafter, Modification 1 will be described in detail with reference to FIG.

  The controller 22 varies the operating frequency f1 of the inverter circuit 21 within the specified range (step S11 in FIG. 6). Next, the control unit 22 obtains the input power P1 at the lower limit and the input power P1 at the upper limit in the specified range, respectively, and obtains a difference ΔP1 between these input powers P1 (step S12 in FIG. 6). ).

  Furthermore, the control unit 22 compares the difference ΔP1 with a predetermined value set in advance, and when the difference ΔP1 is larger than the specified value (NO in step S13 in FIG. 6), the control unit 22 proceeds to step S11. Further, when the difference ΔP1 is equal to or less than the specified value (YES in step S13 in FIG. 6), the control unit 22 stops the inverter circuit 21 (step S14 in FIG. 6). In this case as well, the operating frequency f1 of the inverter circuit 21 can be made less likely to enter the phase advance region than when the operation of the inverter circuit 21 is continued.

  Furthermore, an operation for increasing at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 in the primary side resonance unit 23 may be a predetermined operation. Hereinafter, Modification 2 will be described in detail with reference to FIGS. 7A and 7B.

  FIG. 7A is a schematic circuit diagram showing the primary side capacitor C1 whose capacitance can be adjusted by the control unit 22. FIG. The primary side capacitor C1 includes two capacitors C11 and C12 and two switches QC1 and QC2. The two capacitors C11 and C12 have different capacitances. The switch QC1 is electrically connected in series with the capacitor C11. The switch QC2 is electrically connected in series with the capacitor C12. The series circuit of the capacitor C11 and the switch QC1 and the series circuit of the capacitor C12 and the switch QC2 are electrically connected in parallel.

  FIG. 7B is a schematic circuit diagram showing the primary coil L1 whose inductance can be adjusted by the control unit 22. The primary side coil L1 includes two coils L11 and L12 and a switch QL1. The two coils L11 and L12 are electrically connected in series with each other. The switch QL1 is electrically connected in parallel to one coil L12.

  The switches QC1, QC2, and QL1 are semiconductor switches such as MOSFETs. The switches QC1, QC2, and QL1 are controlled to be turned on / off by the control unit 22, respectively.

  Therefore, in the configuration shown in FIG. 7A, the control unit 22 controls the on / off of the switches QC1 and QC2, so that the capacitance of the primary side capacitor C1 can be adjusted. Similarly, in the configuration shown in FIG. 7B, the control unit 22 can adjust the inductance of the primary coil L1 by controlling the on / off of the switch QL1.

  When the difference ΔP1 between the input power P1 at the lower limit and the input power P1 at the upper limit in the specified range is equal to or less than the specified value, the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 At least one of them is increased. As a result, the frequency characteristic of the inverter circuit 21 shifts in the direction of lowering the frequency, so that the operating frequency f1 of the inverter circuit 21 can be made difficult to enter the phase advance region.

  In the example shown in FIG. 5 and FIG. 6 described above, the difference ΔP between the input power P1 at the lower limit value and the input power P1 at the upper limit value in the above specified range is compared with the above specified value. The difference ΔP1 acquired last time and the difference ΔP2 acquired this time may be compared. In this case, since the frequency at which the difference ΔP2 becomes smaller than the difference ΔP1 becomes an inflection point in the slow phase region, any one of the above-described predetermined operations may be performed when this point is detected. Hereinafter, modifications 3 and 4 will be described with reference to FIGS. 8 and 9.

  First, as a predetermined operation, a case where the operating frequency f1 of the inverter circuit 21 is increased (Modification 3) will be described with reference to FIG. Note that ΔP1 in FIG. 8 is the difference obtained last time.

  The controller 22 varies the operating frequency f1 of the inverter circuit 21 within the specified range (step S21 in FIG. 8). Thereafter, the control unit 22 obtains the input power P1 at the lower limit value and the input power P1 at the upper limit value in the specified range, respectively, and obtains a difference ΔP2 between these input powers P1 (step S22 in FIG. 8). .

  Then, the control unit 22 compares the difference ΔP2 obtained this time with the difference ΔP1 obtained last time, and if the difference ΔP2 is greater than or equal to the difference ΔP1, the process returns to step S21 (NO in step S23 in FIG. 8). . At this time, the controller 22 discards the difference ΔP1 and holds the difference ΔP2 as the next difference ΔP1 (step S25 in FIG. 8).

  Further, when the difference ΔP2 is smaller than the difference ΔP1 (YES in step S23 in FIG. 8), the control unit 22 increases the operating frequency f1 by α (step S24 in FIG. 8). Thereby, compared with the case where the operating frequency f1 of the inverter circuit 21 is not changed, the operating frequency f1 can be made difficult to enter the phase advance region.

  Next, a case where the inverter circuit 21 is stopped as a predetermined operation (Modification 4) will be described with reference to FIG. Note that ΔP1 in FIG. 9 is the difference obtained last time.

  The controller 22 varies the operating frequency f1 of the inverter circuit 21 within the specified range (step S31 in FIG. 9). Thereafter, the control unit 22 obtains the input power P1 at the lower limit value and the input power P1 at the upper limit value in the specified range, respectively, and obtains a difference ΔP2 between these input powers P1 (step S32 in FIG. 9). .

  Then, the control unit 22 compares the difference ΔP2 obtained this time with the difference ΔP1 obtained last time, and if the difference ΔP2 is greater than or equal to the difference ΔP1, the process returns to step S31 (NO in step S33 in FIG. 9). . At this time, the control unit 22 discards the difference ΔP1 and holds the difference ΔP2 as the next difference ΔP1 (step S35 in FIG. 9).

  Further, when the difference ΔP2 is smaller than the difference ΔP1 (YES in step S33 in FIG. 9), the control unit 22 stops the inverter circuit 21 (step S34 in FIG. 9). Thereby, it is possible to make it difficult for the operating frequency f1 to enter the phase advance region as compared with the case where the operation of the inverter circuit 21 is continued.

  In the present embodiment, the input power P1 to the inverter circuit 21 is a physical quantity related to the output power of the inverter circuit 21, but the physical quantity is not limited to the input power P1. For example, the input current to the inverter circuit 21 may be the above physical quantity, or the output power itself of the inverter circuit 21 may be the above physical quantity.

  In the present embodiment, the charging circuit 102 of the electric vehicle 100 is the load 4. However, the load 4 is not limited to the charging circuit 102 and may be any device that requires power supply. Furthermore, although the case where the non-contact power supply device 2 includes the DC power source 20 has been described as an example in the present embodiment, a DC power source may be provided outside the non-contact power supply device 2. Moreover, the non-contact electric power feeder 2 may be provided with the conversion circuit which converts the alternating current power supplied from the outside into direct current power.

  Furthermore, in the present embodiment, the case where the frequency characteristic of the operating frequency f1 of the inverter circuit 21 changes as the ambient temperature changes has been described as an example. However, for example, the operating frequency f1 changes as the vehicle height changes. The technical idea of the present invention may be applied when the frequency characteristic changes.

  In this embodiment, spiral type coils are used as the primary side coil L1 and the secondary side coil L2. However, a solenoid type coil in which a conducting wire is spirally wound around the core may be used.

  However, in the case of a spiral type coil, there is an advantage that unnecessary radiation noise is less likely to occur compared to a solenoid type coil. Further, by using the spiral type coil, unnecessary radiation noise is reduced. As a result, there is an advantage that the range of operating frequencies that can be used in the inverter circuit 21 is expanded. Hereinafter, this point will be described in detail.

  The resonance characteristics in the non-contact power feeding system 1 of the present embodiment change according to the coupling coefficient between the primary side coil L1 and the secondary side coil L2, and show a bimodal characteristic as shown in FIG. 3 under certain conditions. . In the example illustrated in FIG. 3, a frequency region lower than the second frequency fr2 is a “low frequency region”, and a frequency region higher than the second frequency fr2 is a “high frequency region”.

  Here, when the solenoid type coil is employed, when the operating frequency f1 of the inverter circuit 21 is in the “mountain” of the low frequency region and when it is in the “mountain” of the high frequency region, Unwanted radiation noise is smaller when it is on the “mountain”. That is, in the “mountains” in the high frequency region, the current flowing through the primary coil L1 and the current flowing through the secondary coil L2 are in phase. On the other hand, in the “mountains” in the low frequency region, the current flowing through the primary coil L1 and the current flowing through the secondary coil L2 are in opposite phases.

  Therefore, in the “mountain” in the low frequency region, the unnecessary radiation noise generated in the primary side coil L1 and the unnecessary radiation noise generated in the secondary side coil L2 cancel each other, and the entire non-contact power feeding system 1 If it sees, unnecessary radiation noise will be reduced.

  Therefore, even when the solenoid type coil is employed, if the operating frequency f1 of the inverter circuit 21 is in the “mountain” slow phase region (fr1 <f1 <fr2) in the low frequency region, the inverter circuit 21 is in the slow phase mode. It operates and unnecessary radiation noise is also reduced. However, since the slow phase region of the “mountain” in the low frequency region changes according to the coupling coefficient between the primary side coil L1 and the secondary side coil L2, the inverter circuit 21 has such an uncertain slow phase region. Control to accommodate the operating frequency f1 is required.

  On the other hand, in the case of a spiral type coil, even if the operating frequency f1 of the inverter circuit 21 is in the “mountain” slow phase region (higher frequency side than fr3) of the high frequency region, compared to the solenoid type coil. Unwanted radiation noise is greatly reduced. That is, by using the spiral type coil, the operating frequency f1 of the inverter circuit 21 is not limited to the “mountain” slow phase region in the low frequency region, and the range of the operating frequency f1 usable in the inverter circuit 21 is expanded. Will be.

  Although the slow phase region of the “mountain” in the high frequency region is an uncertain region, if the operating frequency f1 of the inverter circuit 21 is swept from a sufficiently high frequency to a low frequency side, the operating frequency f1 becomes “ Since it passes through the lagging region of the mountain, complicated control is unnecessary.

  As described above, the non-contact power feeding device (2) according to the first aspect of the present invention includes the primary side resonance unit (23), the inverter circuit (21), and the control unit (22). The primary side resonance part (23) includes a primary side coil (L1) and a primary side capacitor (C1). The inverter circuit (21) converts DC power into AC power and outputs the AC power to the primary side resonance unit (23). The control unit (22) operates the inverter circuit (21) at a predetermined operating frequency. The control unit (22) measures a physical quantity related to the output power of the inverter circuit (21) by changing the operating frequency within a specified range. When the difference between the physical quantity when the operating frequency (f1) is the lower limit value in the specified range and the physical quantity when the operating frequency (f1) is the upper limit value in the specified range is less than the specified value, the control unit (22). Then, a predetermined operation is performed so that the operating frequency (f1) does not enter the phase advance region.

  According to the first aspect, the operating frequency (f1) of the inverter circuit (21) can be made difficult to enter the phase advance region.

  In the non-contact electric power feeder (2) according to the second aspect of the present invention, in the first aspect, the predetermined operation is an operation for stopping the inverter circuit (21).

  According to the second aspect, the operating frequency of the inverter circuit (21) can be made difficult to enter the phase advance region.

  In the non-contact power feeding device (2) according to the third aspect of the present invention, in the first aspect, the predetermined operation is an operation of increasing the operating frequency (f1) of the inverter circuit (21).

  According to the third aspect, the operating frequency of the inverter circuit (21) can be made difficult to enter the phase advance region.

  In the contactless power supply device (2) of the fourth aspect according to the present invention, in the first aspect, the predetermined operation includes an operation for increasing the inductance of the primary coil (L1) and a capacitance of the primary capacitor (C1). At least one of the increasing operations.

  According to the fourth aspect, the operating frequency of the inverter circuit (21) can be made difficult to enter the phase advance region.

  In the non-contact electric power feeder (2) of the 5th aspect which concerns on this invention, in any aspect among the 1st-4th aspects, a primary side resonance part (23) is a secondary side resonance part (31). Is configured to supply power to the load (4) in a non-contact manner using the electromagnetic coupling. The secondary side resonance part (31) includes a secondary side coil (L2) and a secondary side capacitor (C2). In this case, the operating frequency (f1) of the inverter circuit (21) is higher than the resonant frequency of the primary side resonance part (23), and the minimum necessary for the inverter circuit (21) to operate the load (4). It is below the frequency when outputting electric power.

  According to the fifth aspect, it is possible to supply electric power necessary to operate the load (4) while making the operating frequency of the inverter circuit (21) difficult to enter the phase advance region.

  The contactless power supply system (1) according to the sixth aspect of the present invention includes a contactless power supply device (2) and a contactless power receiving device (3). The non-contact power receiving device (3) receives power supplied from the non-contact power feeding device (2). The non-contact power receiving device (3) includes a secondary side resonance unit (31). The secondary-side resonance unit (31) includes a secondary-side coil (L2) and a secondary-side capacitor (C2), and loads electric power supplied using electromagnetic coupling with the primary-side resonance unit (23) ( Output to 4).

  According to the 6th aspect, by using the above-mentioned non-contact electric power feeder (2), it is possible to make the operating frequency of the inverter circuit (21) difficult to enter the phase advance region.

DESCRIPTION OF SYMBOLS 1 Non-contact electric power feeding system 2 Non-contact electric power feeder 3 Non-contact electric power receiving apparatus 4 Load 21 Inverter circuit 22 Control part 23 Primary side resonance part 31 Secondary side resonance part f1 Operating frequency C1 Primary side capacitor C2 Secondary side capacitor L1 Primary side coil L2 Secondary coil

Claims (6)

A primary side resonance unit including a primary side coil and a primary side capacitor;
An inverter circuit that converts direct current power into alternating current power and outputs the alternating current power to the primary resonance unit;
A control unit for operating the inverter circuit at a predetermined operating frequency,
The controller measures the physical quantity related to the output power of the inverter circuit by varying the operating frequency within a specified range,
When the difference between the physical quantity when the operating frequency is the lower limit value in the specified range and the physical quantity when the operating frequency is the upper limit value in the specified range is less than or equal to the specified value, A non-contact power feeding device that performs a predetermined operation so that an operating frequency does not enter a phase advance region.   The non-contact power feeding apparatus according to claim 1, wherein the predetermined operation is an operation of stopping the inverter circuit.   The non-contact power feeding apparatus according to claim 1, wherein the predetermined operation is an operation of increasing the operating frequency.   The contactless power supply device according to claim 1, wherein the predetermined operation is at least one of an operation of increasing the inductance of the primary side coil and an operation of increasing the capacitance of the primary side capacitor. The primary side resonance unit is configured to supply power to a load in a non-contact manner using electromagnetic coupling with a secondary side resonance unit including a secondary side coil and a secondary side capacitor,
The operating frequency is higher than a resonance frequency of the primary-side resonance unit and is equal to or lower than a frequency at which the inverter circuit outputs a minimum power necessary to operate the load. The non-contact electric power feeder of any one of 1-4. A contactless power supply device according to any one of claims 1 to 5, and a contactless power reception device that receives power supplied from the contactless power supply device,
The non-contact power receiving device includes a secondary-side resonance unit that includes a secondary-side coil and a secondary-side capacitor and outputs power supplied to the load using electromagnetic coupling with the primary-side resonance unit. A contactless power supply system.

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