WO2015182097A1

WO2015182097A1 - Contactless power-supplying device and contactless power-supplying system in which same is used

Info

Publication number: WO2015182097A1
Application number: PCT/JP2015/002603
Authority: WO
Inventors: 田村　秀樹
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2014-05-27
Filing date: 2015-05-22
Publication date: 2015-12-03

Abstract

　Provided is a contactless power-supplying device with which it is possible to suppress a reduction in efficiency due to the positional relationship between a primary coil and a secondary coil. Also provided is a contactless power-supplying system in which said device is used. A contactless power-supplying device (2) is provided with a primary LC circuit (24) that comprises a primary coil (L1) and a primary capacitor (C1), an alternating current power source (21) for inputting alternating current electrical power to the primary LC circuit (24), and a primary control unit (22) for controlling the alternating current power source (21). When the alternating current power source (21) is started and before normal operations begin, the primary control unit (22) carries out a property-estimating operation for estimating the properties of the primary LC circuit (24) while controlling the alternating current power source (21) such that the effective value of the output voltage (V) is lower than the output voltage during normal operation.

Description

Non-contact power supply device and non-contact power supply system using the same

The present invention relates to a non-contact power supply apparatus and a non-contact power supply system using the same, and more specifically to a non-contact power supply apparatus that performs non-contact power supply by electromagnetic induction and a non-contact power supply system using the same.

Conventionally, a non-contact power supply device that performs non-contact power supply by electromagnetic induction has been provided (for example, see Japanese Patent Application Publication No. 2013-211932, hereinafter referred to as “Document 1”). The contactless power supply device described in Document 1 is used together with a contactless power receiving device that receives power from the contactless power supply device.

The non-contact power feeding device includes a primary side coil and an AC power source that inputs AC power to the primary side coil.

Further, the non-contact power receiving device includes a secondary side coil.

That is, when AC power is input from the AC power source to the primary coil, a current is induced in the secondary coil by the electromagnetic field generated by the primary coil, thereby achieving non-contact power feeding.

The non-contact power receiving device is mounted on a vehicle including a relatively large capacity secondary battery and a charging circuit for charging the secondary battery, such as an electric vehicle and a hybrid vehicle, and a power source for the charging circuit described above. Become.

If the non-contact power supply device as described above is used, convenience such as plugging / unplugging / unplugging becomes unnecessary as compared with the case where power supply is performed by wire.

However, in the non-contact power feeding device described above, the mutual inductance between the primary side coil and the secondary side coil changes according to the positional relationship between the primary side coil and the secondary side coil.

For example, when the non-contact power receiving device is mounted on an automobile and the non-contact power feeding device is fixed to the ground, if the position where the automobile is stopped at the time of power feeding is shifted, the mutual inductance is different. If the vehicle height is low, the mutual inductance value and coupling coefficient value between the primary coil of the contactless power supply device on the ground side and the secondary coil present on the vehicle body side are values that can be practically used. It can be operated with. However, if the vehicle height of the automobile is high, the distance between the primary side coil and the secondary side coil is increased, so that the mutual inductance value and the coupling coefficient value are insufficient.

Moreover, the electric power input to the primary coil and the electrical stress applied to the circuit components of the AC power supply depend on the mutual inductance.

Therefore, even if the frequency of the output voltage of the AC power supply is constant, depending on the positional relationship between the primary side coil and the secondary side coil, the life of the AC power supply may be shortened due to excessive electrical stress, and the efficiency may be reduced. May be wasted.

An object of the present invention is to provide a non-contact power feeding device that can suppress a decrease in efficiency due to a positional relationship between a primary side coil and a secondary side coil, and a non-contact power feeding system using the same.

In order to solve the above-described problems, a non-contact power feeding device according to the present invention inputs AC power to a primary side coil, a primary side capacitor that constitutes a primary side LC circuit together with the primary side coil, and the primary side LC circuit. An AC power source configured as described above, a power source control unit that controls the AC power source, and a characteristic estimation unit configured to perform a characteristic estimation operation that estimates a characteristic of the primary side LC circuit. When starting the AC power supply, the control unit sets the effective value of the output voltage to the steady operation before starting the steady operation of controlling the AC power supply so that the frequency of the output voltage is constant. The characteristic estimation unit performs the characteristic estimation operation during the start-up period.

In order to solve the above problems, a non-contact power feeding system of the present invention includes the non-contact power feeding device and a secondary side coil configured to induce a current by an electromagnetic field generated by the primary side coil. And a non-contact power receiving device.

1 is a circuit block diagram illustrating a non-contact power feeding system according to a first embodiment. It is explanatory drawing which shows an example of the usage pattern of the non-contact electric power feeding system which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the example of the frequency characteristic of the primary side LC circuit in the non-contact electric power feeding system which concerns on Embodiment 1 about the case where the coupling coefficient of a primary side coil and a secondary side coil differs, respectively. It is explanatory drawing which shows an example of the time change of the output current I of the alternating current power supply in the slow phase mode, and the output voltage V. FIG. It is explanatory drawing which shows an example of the time change of the output current I and the output voltage V of AC power supply in a phase advance mode. FIG. 3 is an explanatory diagram illustrating an example of frequency characteristics of a primary side LC circuit in the non-contact power feeding system according to the first embodiment. It is explanatory drawing which shows another example of the frequency characteristic of the primary side LC circuit in the non-contact electric power feeding system which concerns on Embodiment 1. FIG. FIG. 3 is a circuit diagram illustrating an example of a primary side capacitor in the non-contact power feeding system according to the first embodiment. 3 is a circuit diagram illustrating an example of a primary side coil in the non-contact power feeding system according to Embodiment 1. FIG. It is a circuit block diagram which shows the example of a change of the non-contact electric power feeding system which concerns on Embodiment 1. It is a circuit diagram which shows the principal part of another modification of the non-contact electric power feeding system which concerns on Embodiment 1. FIG. It is a circuit diagram which shows the principal part of another modification of the non-contact electric power feeding system which concerns on Embodiment 1. FIG. 13A to 13D are explanatory diagrams illustrating examples of first characteristics in the non-contact power feeding system according to the second embodiment. FIG. 14A is an explanatory diagram illustrating an example of frequency characteristics of the primary LC circuit in the non-contact power feeding system according to the second embodiment. FIG. 14B is an explanatory diagram illustrating another example of the frequency characteristics of the primary LC circuit in the wireless power supply system according to the second embodiment. 10 is an explanatory diagram illustrating an example of frequency characteristics of a primary side LC circuit in a non-contact power feeding system according to Embodiment 3. FIG. It is explanatory drawing which shows another example of the frequency characteristic of the primary side LC circuit in the non-contact electric power feeding system which concerns on Embodiment 3. FIG.

As shown in FIG. 1, the non-contact power feeding device 2 according to the present invention includes a primary side coil L1 and a primary side capacitor C1 that constitutes a primary side LC circuit 24 together with the primary side coil L1. The non-contact power feeding device 2 includes an AC power source 21 configured to input AC power to the primary side LC circuit 24 and a primary side control unit 22 as a power source control unit that controls the AC power source 21. Further, the non-contact power feeding device 2 includes a primary side control unit 22 as a characteristic estimation unit configured to perform a characteristic estimation operation of estimating the characteristic of the primary side LC circuit 24. When starting the AC power source 21, the primary side control unit 22 as the power source control unit has a start period before starting a steady operation of controlling the AC power source 21 so that the frequency of the output voltage V is constant. The effective value of the output voltage V is set lower than that during steady operation. The primary side control unit 22 as the characteristic estimation unit performs a characteristic estimation operation during the starting period.

In one example, the primary side control unit 22 as the characteristic estimation unit estimates the characteristic of the primary side LC circuit 24 in a state where the primary side coil L1 is magnetically coupled to the secondary side coil L2. The characteristic of the primary side LC circuit 24 is that the current flowing through the primary side LC circuit 24 with respect to the frequency of the output voltage V output from the AC power source 21 after the primary side coil L1 is magnetically coupled to the secondary side coil L2. This is the frequency characteristic of I. The frequency characteristics (resonance characteristics) of the primary side LC circuit 24 are different for each coupling coefficient k between the primary side coil L1 and the secondary side coil L2. For example, the coupling coefficient k changes when the relative positions of the primary coil L1 and the secondary coil L2 shift. Therefore, the primary side control unit 22 as the characteristic estimation unit performs a characteristic estimation operation for estimating the frequency characteristic of the current I during the start period, and the output that can be fed to the secondary coil L2 side by the non-contact power feeding device 2 in a desired state. Estimate the frequency of the voltage V. And the primary side control part 22 as a characteristic estimation part controls the alternating current power supply 21 so that the frequency of the output voltage V may be made constant, and starts steady operation | movement.

According to said structure, the non-contact electric power feeder 2 can suppress the fall of the efficiency by the positional relationship of the primary side coil L1 and the secondary side coil L2.

In the non-contact power feeding device 2 described above, the primary side control unit 22 as the characteristic estimation unit may estimate the characteristic based on the current in the AC power source 21.

In the non-contact power feeding device 2 described above, the primary side control unit 22 as the characteristic estimation unit may estimate the characteristic based on the difference between the phase of the output voltage V and the phase of the output current I in the AC power supply 21. .

In the non-contact power supply apparatus 2 described above, the primary side control unit 22 as a power supply control unit may gradually change the frequency of the output voltage V of the AC power supply 21 while the characteristic estimation operation is being performed.

In the non-contact power feeding device 2 described above, the primary side control unit 22 as the characteristic estimation unit detects the effective value of the output current I of the AC power supply 21 a plurality of times in a state where the frequency of the output voltage of the AC power supply 21 is different. May be.

In the non-contact power feeding device 2 described above, it is desirable to include a primary side control unit 22 as a characteristic adjustment unit that controls at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1. The primary side control unit 22 as the characteristic adjustment unit determines at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 according to the characteristic estimated by the characteristic estimation operation before the steady operation is started. The characteristic adjustment operation is performed to obtain

In the non-contact power feeding device 2 described above, a storage unit 26 in which a table showing a correspondence relationship between at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 and the characteristic estimated by the characteristic estimation operation is stored in advance. May be provided. In this case, in the characteristic adjustment operation, the primary side control unit 22 serving as the characteristic adjustment unit sets at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 as a table for the characteristic estimated by the characteristic estimation operation. The value associated with.

In the contactless power supply device 2 described above, the primary side control unit 22 as a characteristic adjustment unit changes at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1, and then performs primary side control as a characteristic estimation unit. The unit 22 may estimate the characteristics again.

A non-contact power feeding system 1 according to the present invention includes any non-contact power feeding device 2 described above and a secondary side coil L2 configured to induce a current by an electromagnetic field generated by the primary side coil L1. And a contact power receiving device 3.

In the non-contact power feeding system 1 described above, the non-contact power receiving device 3 includes an open / close unit 31 that opens and closes an electric path between both ends of the secondary coil L2, and a secondary control unit 32 that controls the open / close unit 31. May be. In this case, it is preferable that the secondary side control unit 32 turns on the opening / closing unit 31 during the period during which the characteristic estimation operation is performed, and turns off the opening / closing unit 31 during the period during which the steady operation is performed. .

In the above non-contact power feeding system, the non-contact power receiving device 3 includes a rectifying unit 30 that rectifies the output of the secondary coil L2, and the opening / closing unit 31 is electrically connected between the output terminals of the rectifying unit 30. It is desirable that

According to said structure, the non-contact electric power feeding system can suppress the fall of the efficiency by the positional relationship of the primary side coil L1 and the secondary side coil L2.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, the non-contact electric power feeding system 1 which concerns on Embodiment 1 of this invention is demonstrated. As shown in FIG. 1, the non-contact power feeding system 1 according to Embodiment 1 of the present invention includes a non-contact power feeding device 2 and a non-contact power receiving device 3.

The non-contact power feeding device 2 includes a primary side coil L1, a primary side capacitor C1 that forms the primary side LC circuit 24 together with the primary side coil L1, an AC power source 21 that supplies AC power to the primary side LC circuit 24, and an AC power source. The primary side control part 22 as a power supply control part which controls 21 is provided.

The AC power source 21 includes a DC power source unit 210 that can change the output voltage, and an inverter unit 211 that converts the output of the DC power source unit 210 into AC and outputs the AC voltage to the primary LC circuit 24.

The inverter unit 211 is a so-called full bridge type inverter circuit in which a series circuit of two switching elements Q1 and Q2 and a series circuit of two switching elements Q3 and Q4 are connected in parallel to each other. Each series circuit is electrically connected in parallel between a pair of output terminals of the DC power supply unit 210. A connection point between the switching element Q1 and the switching element Q2 is electrically connected to one input terminal of the primary side LC circuit 24. A connection point between the switching element Q3 and the switching element Q4 is electrically connected to the other input terminal of the primary side LC circuit 24. In the example of FIG. 1, n-channel and enhancement type MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are used as the switching elements Q1 to Q4. In each of the switching elements Q1 to Q4, the drain is directed to the high potential side, the source is directed to the low potential side, and the gate is connected to the primary side control unit 22. As the switching elements Q1 to Q4, other known semiconductor switches such as IGBTs (Insulated Gate Bipolar Transistors) may be used.

The primary-side control unit 22 uses a rectangular-wave-shaped first drive signal G1 whose duty ratio is slightly lower than 50% to switch the switching element Q1 on the high potential side of one series circuit of the inverter unit 211 and the low level of the other series circuit. The potential side switching element Q4 is driven. Further, the primary side control unit 22 switches the remaining two switching units of the inverter unit 211 by a rectangular-wave-like second drive signal G2 having a common duty ratio and frequency with respect to the first drive signal G1 and having a phase different by 180 degrees. Elements Q2 and Q3 are driven. That is, the pair of two switching elements Q1 and Q4 positioned diagonally to each other and the pair of the remaining two switching elements Q2 and Q3 are alternately turned on and off. Thereby, the output voltage of the DC power supply unit 210 is alternated and input to the primary side LC circuit 24. In other words, the inverter unit 211 inverts the polarity of the output voltage of the DC power supply unit 210 in accordance with the first drive signal G1 and the second drive signal G2, and outputs the result to the primary side LC circuit 24. The primary side control part 22 is realizable using a microcomputer, for example.

In addition, the DC power supply unit 210 is configured such that the height of the output voltage is variable under the control of the primary side control unit 22. Specifically, DC power supply unit 210 is formed by connecting a series circuit of battery E1 and switch QE1 and a series circuit of battery E2 and switch QE2 in parallel with each other. The switches QE1 and QE2 are on / off controlled by the primary side control unit 22, respectively. As the switches QE1 and QE2 as described above, for example, known semiconductor switches can be used. The batteries E1 and E2 have different output voltages. In the present embodiment, the battery E1 outputs a higher output voltage than the battery E2. That is, a voltage having a different height is output from the DC power supply unit 210 depending on which of the switches QE1 and QE2 is turned on by the primary side control unit 22.

Alternatively, the output voltage of the DC power supply unit 210 may be variable by using a known switching power supply circuit controlled by the primary side control unit 22 as the DC power supply unit 210.

The non-contact power receiving device 3 includes a secondary side coil L2 configured such that current is induced by an electromagnetic field generated by the primary side coil L1, and a secondary side capacitor C2 connected in series to the secondary side coil L2. With. In addition, the non-contact power receiving device 3 includes a rectifier 30 that performs full-wave rectification on the output of the secondary coil L2 by connecting AC input terminals to both ends of the series circuit of the secondary coil L2 and the secondary capacitor C2. And an output capacitor C3 that smoothes the output of the rectifying unit 30. That is, the current induced in the secondary coil L2 is rectified by the rectifier 30 and the output capacitor C3 is charged by the rectified current. Both ends of the output capacitor C3 are electrically connected to the subsequent load 91 as output terminals of the non-contact power receiving device 3.

The load 91 is a charging circuit that is mounted on the automobile 9 as shown in FIG. 2 and charges the secondary battery 90 with electric power obtained by appropriately converting the output of the non-contact power receiving device 3. In this case, the secondary coil L2 is disposed below the automobile 9, and the non-contact power feeding device 2 is fixed to the ground. By stopping the automobile 9 so that the secondary coil L2 is positioned on the primary coil L1, power can be supplied from the non-contact power supply device 2 to the non-contact power reception device 3, and thus the secondary battery 90 Charging becomes possible.

Hereinafter, the operation of the primary side control unit 22 at the start, which is a feature of the present embodiment, will be described.

When the primary side control unit 22 starts the AC power supply 21, the frequencies of the first drive signal G1 and the second drive signal G2 (that is, the frequency of the output voltage V of the AC power supply 21; hereinafter referred to as “operation frequency”). The characteristics of the primary side LC circuit 24 are estimated during the start-up period before starting a steady operation with f being constant. That is, the primary side control unit 22 also serves as a characteristic estimation unit that performs a characteristic estimation operation of estimating the characteristic of the primary side LC circuit 24.

The primary side control unit 22 controls the DC power supply unit 210 so that the effective value of the output voltage V of the AC power supply 21 is lower during the characteristic estimation operation than during the steady operation. Specifically, when the DC power supply unit 210 is configured as shown in FIG. 1, the switch QE1 connected in series to the battery E1 whose output voltage is higher than that of the battery E2 is turned off, and the output voltage is lower than that of the battery E1. The switch QE2 connected to the battery E2 is turned on.

The non-contact power feeding device 2 includes a current detection unit 25 that detects a current (hereinafter simply referred to as “output current”) I output from the AC power supply 21 to the primary coil L <b> 1, and a storage unit 26. . As the current detection unit 25, for example, a shunt resistor or a Hall element may be used. As the storage unit 26, a known memory can be used. During the characteristic estimation operation, the primary side control unit 22 obtains an effective value Ie of the output current I detected by the current detection unit 25 and stores it in the storage unit 26 a plurality of times while gradually changing the operation frequency f. I do. With the above operation, the storage unit 26 stores the frequency characteristics of the primary side LC circuit 24. In addition to using the effective value Ie output from the current detection unit 25, the primary side control unit 22 may obtain the effective value Ie by calculation from the instantaneous value of the current I detected by the current detection unit 25. Regarding the effective value Ie of the current I, the current detection unit 25 outputs, for example, a voltage proportional to the effective value Ie of the current I to the primary side control unit 22 in addition to outputting the effective value Ie of the current I. It may be configured as follows. Furthermore, the current detection unit 25 may detect and output a representative value (a peak value, an average value, etc.) other than the effective value Ie instead of the effective value Ie of the output current I of the AC power supply 21.

Further, when the characteristic estimation operation is finished and the steady operation is started, the primary side control unit 22 causes the DC power supply unit 210 of the AC power supply 21 to have a higher effective value of the output voltage V than during the characteristic estimation operation. To control. Specifically, when the DC power supply unit 210 is configured as shown in FIG. 1, the switch QE2 connected to the battery E2 whose output voltage is lower than the battery E1 is turned off, and the battery whose output voltage is higher than that of the battery E2. The switch QE1 connected in series with E1 is turned on.

Here, the frequency characteristics of the primary side LC circuit 24 are different for each coupling coefficient k between the primary side coil L1 and the secondary side coil L2, as shown in FIG. Specifically, when the coupling coefficient k is small to some extent (for example, k ≦ 0.1), the maximum value of the frequency characteristic is one place, and no minimum value is generated. However, when the coupling coefficient k is large to some extent (for example, k ≧ 0.15), the maximum value of the frequency characteristic is generated at two locations, and the minimum value is generated at the frequency between the two maximum values. Further, the larger the coupling coefficient k (that is, the greater the mutual inductance), the larger the interval between the maximum frequency.

Further, as the operation mode of the AC power source 21, the phase of the output current I is delayed from the phase of the output voltage V as shown in FIG. 4, and the output current I of the AC power source 21 as shown in FIG. There is a phase advance mode in which the phase advances more than the phase of the output voltage V.

In the AC power source 21, when the effective value Ie of the output current I has a positive correlation with the operating frequency f, the operating mode is a phase advance mode. When the frequency characteristic has only one maximum value as shown in FIG. 6, the frequency band in which the operation mode becomes the phase advance mode as described above is on the lower frequency side (f <fr0) than the frequency fr0 of the maximum value. . When the frequency characteristic has two maximum values as shown in FIG. 7, the frequency band in which the operation mode is the phase advance mode is lower than the frequency fr1 of the maximum value on the low frequency side (f <fr1), and the minimum value. Between the frequency fr2 and the maximum frequency fr3 on the high frequency side (fr2 <f <fr3).

Further, in the AC power source 21, when the effective value Ie of the output current I has a negative correlation with the operating frequency f, the operating mode is a slow phase mode. When the frequency characteristic has only one maximum value as shown in FIG. 6, the frequency band in which the operation mode becomes the slow phase mode is higher frequency side (right side) f> fr0 than the frequency fr0 of the maximum value. When the frequency characteristic has the maximum value at two places as shown in FIG. 7, the frequency band in which the operation mode is the slow phase mode is between the maximum frequency fr1 and the minimum frequency fr2 on the low frequency side (fr1 < f <fr2) and the high frequency side (f> fr3) from the maximum value fr3 on the high frequency side.

In the advanced phase mode, switching of the switching elements Q1 to Q4 is so-called hard switching, so that the electrical stress applied to the switching elements Q1 to Q4 is relatively high and the power consumption is relatively increased. On the other hand, in the slow phase mode, switching of the switching elements Q1 to Q4 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 suppressed from being applied to the switching elements Q1 to Q4. Therefore, it is desirable that the operation mode of the AC power supply 21 is a slow phase mode.

However, whether the operation mode is the slow phase mode or the fast phase mode with respect to a certain operating frequency f depends on the coupling coefficient k. For example, when the operating frequency f is the frequency f1 shown in FIG. 3, if the coupling coefficient k is 0.25 or 0.35, the operating mode is the slow phase mode, but if the coupling coefficient k is 0.15. The operation mode becomes the phase advance mode.

Therefore, the primary side control unit 22 operates so as to set the operation mode in the steady operation to the slow phase mode. Specifically, for example, the operating frequency f during steady operation is a frequency included in the frequency band of the slow phase mode estimated in the characteristic estimation operation. When the frequency characteristic has maximum values at two locations, the frequency band on the low frequency side (that is, sandwiched between the two maximum values) out of the two frequency bands fr1 <f <fr2, f> fr3 that are in the slow phase mode. In order to suppress unnecessary radiation, it is desirable to use fr1 <f <fr2.

In the frequency sweep of the characteristic estimation operation, the range of the operating frequency f to be changed is, for example, a range that includes at least the frequency fr1 of the maximum value on the low frequency side and the frequency of the minimum value fr2 within the range of assumed conditions ( For example, 70 kHz to 120 kHz). Further, the frequency resolution in the frequency sweep (that is, the interval of the operating frequency f for storing the effective value Ie of the output current I) is, for example, 1 kHz.

Alternatively, the primary-side control unit 22 changes the characteristic of the primary-side LC circuit 24 so that the operating frequency f during steady-state operation is a fixed value (for example, 85 kHz, hereinafter referred to as “steady-frequency”) fs. A mode may be realized. In this case, the primary side control unit 22 also serves as a characteristic adjustment unit. If this configuration is adopted, the frequency of noise generated by the non-contact power feeding device 2 during the steady operation becomes substantially constant, so that the above-described noise hardly affects other devices.

In order to change the characteristics of the primary side LC circuit 24 as described above, at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 can be changed by the control of the primary side control unit 22. There is a need.

As the primary side capacitor C1 whose capacitance can be changed by the control of the primary side control unit 22, in addition to a known varactor diode, for example, a configuration shown in FIG. The primary side capacitor C1 in FIG. 8 includes two capacitors C11 and C12 having different capacitances and two switches QC1 and QC2 connected in series to the one capacitor C11 and C12, respectively. A series circuit composed of one capacitor C11 and one switch QC1 and a series circuit composed of another capacitor C12 and another switch QC2 are connected in parallel to each other. .

Further, as the primary side coil L1 whose inductance can be changed by the control of the primary side control unit 22, for example, a configuration shown in FIG. 9 can be considered. The primary coil L1 in FIG. 9 includes two coils L10 and L11 connected in series with each other, and a switch QL1 connected in parallel with one coil L11.

The above switches QC1, QC2 and QL1 are on / off controlled by the primary side control unit 22, respectively. As the switches QC1, QC2, and QL1, known semiconductor switches such as MOSFETs can be used.

When the stationary frequency fs is not included in the frequency band of the slow mode in the frequency characteristic estimated by the characteristic estimation operation, the primary side control unit 22 causes the stationary frequency fs to be included in the frequency band of the slow mode. The characteristics of the primary side LC circuit 24 are changed.

Here, the capacitance of the primary side capacitor C1 is C, the inductance of the primary side coil L1 is L, and the mutual inductance between the primary side coil L1 and the secondary side coil L2 is M. Then, the maximum frequency fr0 in the case of FIG. 6, the maximum frequency fr1, the minimum frequency fr2, and the maximum frequency fr3 on the high frequency side in the case of FIG. expressed.

That is, the higher the capacitance C and the inductance L, the lower the respective frequencies fr0 to fr3.

For example, let us consider a case where, in the frequency characteristic estimated in the characteristic estimation operation, the stationary frequency fs is lower than the maximum frequency fr1 on the low frequency side. In this case, the primary side control unit 22 increases the capacitance C and the inductance L in order to make the maximum frequency fr1 lower than the steady frequency fs. Specifically, for example, as shown in FIG. 8, when only the switch QC1 on the capacitor C11 side whose capacitance is larger than the capacitor C12 is turned on in the primary side capacitor C1 during the characteristic estimation operation, both switches QC1 in the steady operation. , QC2 is turned on. As a result, the combined capacitance of the primary side capacitor C1 is increased, so that the capacitance of the primary side capacitor C1 can be increased. Or, for example, as shown in FIG. 9, when the switch QL1 is turned on in the primary coil L1 during the characteristic estimation operation, the switch QL1 is turned off in the steady operation. Thereby, since the synthetic | combination inductance of the primary side coil L1 becomes large, the inductance of the primary side coil L1 can be raised.

Or, consider the case where the steady frequency fs is higher than the minimum frequency fr2 in the frequency characteristic estimated in the characteristic estimation operation. In this case, the primary side control unit 22 lowers the capacitance C and the inductance L in order to make the frequency fr2 having the minimum value higher than the steady frequency fs. Specifically, for example, when only the switch QC1 on the side of the capacitor C11 having a larger capacitance in the primary side capacitor C1 is turned on during the characteristic estimation operation, the switch QC1 is turned off in the steady operation and the other switch is turned on. Turn on QC2. Alternatively, for example, when the switch QL1 is turned off in the primary coil L1 during the characteristic estimation operation, the switch QL1 is turned on in the steady operation.

As a result of the control described above, even if the steady-state frequency fs is included in the frequency band of the fast-phase mode in the characteristic during the characteristic estimation operation, the frequency band of the slow-phase mode in the characteristic during the steady-state operation has the steady frequency fs. (That is, fr1 <fs <fr2).

In the example of FIG. 8, if the number of series circuits of the capacitors C11 and C12 and the switches QC1 and QC2 is increased, the capacitance of the primary capacitor C1 can be changed in multiple stages. In the example of FIG. 9, if the number of parallel circuits of the coil L11 and the switch QL1 is increased, the inductance of the primary side coil L1 can be changed in more stages.

Further, a table stored in advance in the storage unit 26 may be used for determination of capacitance and inductance. As a part for storing the table in the storage unit 26, a known nonvolatile memory such as a read-only memory (so-called ROM: read only memory) or a flash memory can be used. The above table shows the correspondence between the characteristics estimated during the characteristic estimation operation (specifically, for example, the frequency fr1 having the maximum value on the low frequency side) and the capacitance of the primary capacitor C1 and the inductance of the primary coil L1. Show. In the above table, parameters that indirectly indicate capacitance and inductance (for example, ON / OFF states of the switches QC1, QC2, and QL1) may be shown instead of the numerical values of capacitance and inductance themselves.

Furthermore, after the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 are switched as described above, the estimation of characteristics may be performed again.

Alternatively, the characteristic detected in the characteristic estimation operation may be an operation mode in a state where the operating frequency f is set to the steady frequency fs. In the characteristic estimation operation, the primary side control unit 22 advances the operation mode based on the difference between the phase of the output voltage V of the AC power supply 21 and the phase of the output current I in a state where the operating frequency f is the steady frequency fs. Estimate whether phase mode or slow mode. More specifically, the primary side control unit 22 compares the timing at which the switching elements Q1 to Q4 of the inverter unit 211 are switched (that is, the phase of the drive signals S1 and S2) with the zero crossing timing of the output current I. When the estimated operation mode is the phase advance mode, the primary side control unit 22 changes the characteristics of the primary side LC circuit 24 and then estimates the operation mode again. The change of the characteristic of the primary side LC circuit 24 is achieved, for example, by changing at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 as described above. When the estimated operation mode is the slow phase mode, the primary side control unit 22 ends the characteristic estimation operation and shifts to a steady operation.

According to the above configuration, since the characteristic depending on the positional relationship between the primary side coil L1 and the secondary side coil L2 is estimated before the start of the steady operation, the control according to the estimated characteristic causes the above-mentioned in the steady operation. It is possible to suppress a decrease in efficiency due to characteristic fluctuations.

Even if the operating frequency f is in the phase advance mode frequency band during the characteristic estimation operation, the effective value of the output voltage V of the AC power supply 21 is set lower during the characteristic estimation operation than during steady operation. As a result, electrical stress applied to the AC power supply 21 can be suppressed.

By the way, when the load 91 has a high input impedance with respect to a low input voltage, a current flows through the secondary coil L2 because the discharge from the output capacitor C3 to the load 91 is not achieved during the characteristic estimation operation. There is no possibility. If no current flows in the secondary coil L2 in this way, mutual inductance M does not occur between the primary coil L1 and the secondary coil L2, and therefore the characteristics of the primary LC circuit 24 are in steady operation. It will be different from the characteristics.

Therefore, the non-contact power receiving device 3 of the present embodiment includes an electric circuit between the DC output ends of the rectifying unit 30 (that is, an electric circuit between both ends of the secondary coil L2 and does not include the output capacitor C3 and includes the rectifying unit 30. An open / close unit 31 that opens and closes the electrical circuit) and a secondary-side control unit 32 that controls the open / close unit 31.

The opening / closing unit 31 includes a series circuit of a resistor 310 and a switch 311 that is driven on and off by the secondary-side control unit 32. The resistor 310 can be omitted if the allowable current of the switch 311 is sufficiently high.

Further, as shown in FIG. 1, the non-contact power feeding device 2 and the non-contact power receiving device 3 include

communication units

23 and 33 that communicate with each other by a radio signal using radio waves as a medium, for example. Since

such communication units

23 and 33 can be realized by a well-known technique, detailed description thereof is omitted.

Also, at the start of the characteristic estimation operation, the primary side control unit 22 controls the communication unit 23 to transmit an on signal that is a radio signal instructing to turn on the opening / closing unit 31. When the ON signal is received by the communication unit 33, the secondary side control unit 32 controls the switch 311 to turn on and closes the opening / closing unit 31. As a result, a current flows through the secondary coil L2 regardless of the characteristics of the load 91.

Furthermore, the primary side control part 22 controls the communication part 23 at the time of the start of steady operation, and transmits the OFF signal which is a radio signal which instruct | indicates the opening / closing part 31 to be turned off. When the above-described OFF signal is received by the communication unit 33, the secondary side control unit 32 controls the switch 311 to be turned off to turn off (open) the opening / closing unit 31.

Here, the opening / closing unit 31 may be provided before the rectifying unit 30. However, as described above, an element such as a MOSFET that cuts off only in one direction is used as the switch 311 when provided in the subsequent stage of the rectifying unit 30. It is desirable because it can.

It goes without saying that structural aspects such as circuit component configuration and arrangement are not limited in any way.

For example, the primary side control unit 22 does not necessarily need to be configured by one chip. As a circuit included in the primary side control unit 22, for example, there is a circuit corresponding to a power supply control unit. As a circuit corresponding to the power supply control unit, there are a circuit for driving the switching elements Q1 to Q4 of the inverter unit 211, a circuit for driving the switches QE1 and QE2 of the DC power supply unit 210, and the like. In addition to the above, the circuit included in the primary side control unit 22 includes a circuit corresponding to a characteristic estimation unit. As a circuit corresponding to the characteristic estimation unit, a circuit for estimating the maximum value frequency fr1 and the minimum value frequency fr2 from the frequency characteristics stored in the storage unit 26, or whether the operation mode is the fast phase mode or the slow phase mode is estimated. There is a circuit to do. Further, as a circuit included in the primary side control unit 22, in addition to the above, there is a circuit corresponding to the characteristic adjustment unit. The circuit corresponding to the characteristic adjusting unit is specifically a circuit that drives the switches QC1, QC2, and QL1, for example. Circuits other than the above included in the primary side control unit 22 include a circuit that controls the communication unit 23.

The various circuits described above may be mounted on separate printed wiring boards when not integrated. For example, a circuit for driving the switching elements Q1 to Q4 of the inverter unit 211 and a circuit corresponding to the characteristic estimation unit may be mounted on separate printed wiring boards.

However, the larger the number of components and the longer the electric circuit between the elements, the larger the size and the power consumption increase. Therefore, as many circuits as possible are integrated on one chip or printed wiring common to each other. It is desirable to be mounted on a board. Furthermore, a part or all of the storage unit 26 and the communication unit 23 may be integrated on one chip together with the primary side control unit 22.

Further, the current detection unit 25 may detect an input current from the DC power supply unit 210 to the inverter unit 211 as shown in FIG. 10 instead of detecting the output current I of the AC power supply 21 as shown in FIG. . When the characteristic estimated by the characteristic estimation operation is the operation mode (advanced phase mode or delayed phase mode), detection of the output current I of the AC power source 21 as shown in FIG. Is desirable because it becomes easier. When the characteristic estimated by the characteristic estimation operation is a frequency characteristic, the configuration for obtaining the effective value Ie can be relatively simplified when the input current of the AC power supply 21 is detected as shown in FIG. desirable. Further, in the case of FIG. 10, since the fluctuation of the current detected by the current detection unit 25 is less than that in the case of FIG. That is, the primary side control unit 22 as the characteristic estimation unit estimates the characteristic of the primary side LC circuit 24 based on the current in the AC power source 21 (the output current I of the AC power source 21 or the input current of the AC power source 21). Also good.

Further, when an element inserted in the electric circuit, such as a shunt resistor, is used as the current detection unit 25, a switch that is controlled by the primary side control unit 22 and is turned off during the characteristic estimation operation and turned on during the steady operation. May be connected to the current detection unit 25 in parallel. If this configuration is adopted, power consumption by the current detection unit 25 can be suppressed during steady operation.

Further, the non-contact power receiving device 3 may be configured to detect the current and change the capacitance and inductance as performed in the non-contact power feeding device 2 in the above example. In this case, notification of the detected current and an instruction to change the capacitance or inductance are performed by communication via the

communication units

23 and 33. However, it is desirable that the detection of current and the change of capacitance and inductance be performed by the non-contact power feeding device 2 because the configuration can be made relatively simple.

Furthermore, the primary side capacitor C1 may be incorporated in a capacity adjustment circuit 240 as shown in FIG. The capacitance adjustment circuit 240 of FIG. 11 has four switching elements Q5 to Q8 each made of an n-channel and enhancement type MOSFET. Of the four switching elements Q5, the two switching elements Q5 and Q7 have their drains electrically connected to each other, and the other two switching elements Q6 and Q8 have their sources electrically connected to each other. Yes. The source of one switching element Q5 among the switching elements Q5 and Q7 whose drains are electrically connected to each other is electrically connected to one output terminal of the AC power supply 21. Further, the drain of one switching element Q6 among the switching elements Q6 and Q8 whose sources are electrically connected to each other is also electrically connected to the one output terminal of the AC power supply 21. Furthermore, the source of the other switching element Q7 among the switching elements Q5 and Q7 whose drains are electrically connected to each other is electrically connected to one end of the primary coil L1. The drain of the other switching element Q8 among the switching elements Q6 and Q8 whose sources are electrically connected to each other is also electrically connected to the one end of the primary coil L1. The primary side capacitor C1 is connected between the drains of the switching elements Q5 and Q7 whose drains are electrically connected to each other and the sources of the two switching elements Q6 and Q8 whose sources are electrically connected to each other. Is electrically connected. The primary side control unit 22 drives the switching element Q5 whose source is connected to the AC power supply 21 and the switching element Q8 whose drain is connected to the primary side coil L1 by a third drive signal G3 that is common to each other. Further, the primary side control unit 22 drives the switching element Q6 whose drain is connected to the AC power source 21 and the switching element Q7 whose source is connected to the primary side coil L1 by the fourth drive signal G4 that is common to each other. The third drive signal G3 and the fourth drive signal G4 are rectangular waves each having a duty ratio of about 50%, and the phase of the third drive signal G3 and the phase of the fourth drive signal G4 are different by 180 degrees. . That is, the third drive signal G3 and the fourth drive signal G4 are alternately at the H level. In other words, the first state in which the third drive signal G3 is at the H level and the fourth drive signal G4 is at the L level, and the third drive signal G3 is at the L level and the fourth drive signal G4 is at the H level. The second state is repeated alternately.

In the first state, the output current I passes through the primary capacitor C1 during the period when the output voltage V of the AC power supply 21 is positive. However, in the first state, during the period in which the output voltage V of the AC power supply 21 is negative, the output current I includes the switching element Q8 whose drain is connected to the primary coil L1 and the drain to the AC power supply 21. It passes through the parasitic diode of the connected switching element Q6. That is, in the first state, the output current I does not pass through the primary capacitor C1 during the period when the output voltage V of the AC power supply 21 is negative.

Conversely, in the second state, the output current I does not pass through the parasitic diode of the switching element Q5 and the primary capacitor C1 during the period when the output voltage V of the AC power supply 21 is positive. When the voltage V is negative, the output current I passes through the primary side capacitor C1.

If the capacity adjustment circuit 240 as described above is used, the primary control unit 22 can reduce reactive power by appropriately adjusting the phase difference between the first drive signal G1 and the third drive signal G3.

Further, the capacitance adjusting circuit 240 is realized by using two double gate type bidirectional switches Q9 and Q10 as shown in FIG. 12 instead of using the four switching elements Q5 to Q8 as described above. May be. The bidirectional switches Q9 and Q10 have two gates, and function as diodes in the direction corresponding to the gate whose input is at the H level when only the input to one gate is at the H level. To do. In the example of FIG. 12, one bidirectional switch Q9 is connected in series with the capacitor C1 between the AC power source 21 and the primary side coil L1, and the other bidirectional switch Q10 includes the one bidirectional switch Q9 and the capacitor C1. Are connected in parallel to the series circuit. In each of the bidirectional switches Q9 and Q10, the third drive is performed so that the conduction directions of the two bidirectional switches Q9 and Q10 are opposite to each other in both the first state and the second state. The signal G3 and the fourth drive signal G4 are input to different gates.

(Embodiment 2)
Hereinafter, the non-contact electric power feeding system 1 which concerns on Embodiment 2 of this invention is demonstrated. In the non-contact power feeding system 1 of the present embodiment, the description of the components common to the non-contact power feeding system 1 of the first embodiment is omitted as appropriate.

In the non-contact power feeding system 1 of the first embodiment, in the frequency sweep of the characteristic estimation operation, the operating frequency f is changed in a range including at least the maximum frequency fr1 and the minimum frequency fr2 on the low frequency side. . However, in the future, the range of frequencies that can be used in the wireless power supply system 1 may be limited by laws and standards. In this case, in the non-contact power feeding system 1 of the first embodiment, in the frequency sweep of the characteristic estimation operation, the operating frequency f cannot be changed in the above range, and the frequency characteristic of the primary side LC circuit 24 may not be estimated. There is.

The contactless power feeding system 1 of the present embodiment is characterized in that the frequency characteristic of the primary side LC circuit 24 can be estimated by the characteristic estimation operation even when the usable frequency range is limited. Hereinafter, the characteristics of the non-contact power feeding system 1 of the present embodiment will be described in detail. In the following description, the lowest frequency in the usable frequency range is ‘fl1’ and the highest frequency is ‘fl2’ (fl1 <f <fl2). The usable frequency range is, for example, a frequency range centered on 85 kHz.

In the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 as a characteristic estimation unit performs a first process, a second process, and a third process in the characteristic estimation operation. The first process is a process of estimating a frequency characteristic (hereinafter referred to as “first characteristic”) in the usable frequency range of the primary side LC circuit 24 by performing a frequency sweep in the usable frequency range. It is. In other words, the first process executes a frequency sweep that detects a measurement value related to the characteristics of the primary side LC circuit 24 a plurality of times while gradually changing the frequency of the output voltage V of the AC power supply 21 in a predetermined frequency range. In this way, the first characteristic of the primary side LC circuit 24 is estimated. Here, the measured value is the effective value Ie of the output current I of the AC power supply 21.

Examples of the first characteristic estimated by the first process are shown in FIGS. 13A to 13D. As shown in FIG. 13A, in the first characteristic, when the effective value Ie of the output current I increases as the frequency increases, the operation mode is estimated as the phase advance mode. Further, as shown in FIG. 13B, when the effective value Ie of the output current I decreases as the frequency increases in the first characteristic, the operation mode is estimated to be the slow mode. Further, as shown in FIG. 13C, when the effective value Ie of the output current I increases and then decreases as the frequency increases in the first characteristic, the operation mode shifts from the advanced phase mode to the delayed phase mode. Mode (hereinafter referred to as “first transition mode”). Further, as shown in FIG. 13D, when the effective value Ie of the output current I decreases after the frequency increases in the first characteristic and then increases, the operation mode shifts from the slow phase mode to the fast phase mode. Mode (hereinafter referred to as “second transition mode”).

Here, it is difficult to estimate the frequency characteristic of the primary side LC circuit 24 only with the first characteristic estimated by the first processing. For example, when the first characteristic shown in FIG. 13A is estimated by the first process, the primary control unit 22 is in any mode of the low-frequency-side phase advance mode and the high-frequency-side phase advance mode. It is difficult to estimate. When the first characteristic shown in FIG. 13B is estimated by the first processing, the primary side control unit 22 is in any mode of the low-frequency side slow mode and the high-frequency side slow mode. It is difficult to estimate.

Therefore, the primary side control unit 22 executes the second process after the first process. The second process is a process of changing at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1. Since the method for changing the capacitance of the primary side capacitor C1 or the inductance of the primary side coil L1 has already been described in the first embodiment, the description thereof is omitted here.

As an example, FIGS. 14A and 14B show changes in frequency characteristics of the primary side LC circuit 24 when the capacitance of the primary side capacitor C1 is changed. FIG. 14A shows a case where there are two local maximum values, and the frequency characteristic before changing the capacitance of the primary side capacitor C1 is indicated by a first curve FC1. In FIG. 14A, when the capacitance of the primary side capacitor C1 is increased, the frequency characteristic of the primary side LC circuit 24 shifts from the first curve FC1 to the second curve FC2. In FIG. 14A, when the capacitance of the primary side capacitor C1 is reduced, the frequency characteristic of the primary side LC circuit 24 shifts from the first curve FC1 to the third curve FC3.

FIG. 14B shows a case where there is only one maximum value, and the frequency characteristic before changing the capacitance of the primary side capacitor C1 is indicated by a fourth curve FC4. In FIG. 14B, when the capacitance of the primary side capacitor C1 is increased, the frequency characteristic of the primary side LC circuit 24 shifts from the fourth curve FC4 to the fifth curve FC5. In FIG. 14B, when the capacitance of the primary side capacitor C1 is reduced, the frequency characteristic of the primary side LC circuit 24 shifts from the fourth curve FC4 to the sixth curve FC6.

Thus, since the frequency characteristic of the primary side LC circuit 24 is changed by the second processing, the frequency characteristic in the usable frequency range of the primary side LC circuit 24 is also changed. Then, the primary-side control unit 22 estimates the frequency characteristic (hereinafter referred to as “second characteristic”) in the usable frequency range of the primary-side LC circuit 24 by performing a frequency sweep after the second process. The third process is executed.

In the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 in the second process, at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 by an amount corresponding to the first characteristic. It has changed. And the primary side control part 22 determines the value of the capacitance of the primary side capacitor | condenser C1, and the inductance of the primary side coil L1 by 3rd process.

The third process includes a process of performing frequency sweep and a process of determining whether or not the operation mode is the slow phase mode based on the estimated second characteristic. In the third process, the primary side control unit 22 performs a frequency sweep in order to estimate the frequency characteristic changed from the first characteristic to the second characteristic by the second process. And the primary side control part 22 determines whether an operation mode is a late phase mode based on the estimated 2nd characteristic. When determining that the operation mode is the slow phase mode, the primary side control unit 22 ends the characteristic estimation operation. The primary side control part 22 performs a 2nd process again, when it determines with an operation mode being a phase advance mode. That is, the primary side control unit 22 repeats the second process and the third process until it determines that the operation mode is the slow phase mode.

Hereinafter, specific examples for determining the values of the capacitance of the capacitor C1 and the inductance of the primary coil L1 will be described. First, an example in which the primary side control unit 22 determines the capacitance value of the capacitor C1 will be described. For example, when it is estimated from the first characteristic that the operation mode is the phase advance mode (see FIG. 13A), the primary side control unit 22 reduces the capacitance of the primary side capacitor C1 in the second process, and then performs the third process. Execute. When it is estimated from the second characteristic estimated by the third process that the operation mode is the phase advance mode again, the primary side control unit 22 determines that the changed operation mode is the phase advance mode on the low frequency side. presume. Then, the primary side control unit 22 sets the capacitance of the primary side capacitor C1 to be larger than the initial value so that the operation mode becomes the low-frequency side slow-phase mode, and ends the characteristic estimation operation. Thereby, the value of the capacitance of the primary side capacitor C1 is set to a value larger than the initial value.

On the other hand, when it is estimated from the second characteristic estimated by the third process that the operation mode is the slow-phase mode, the primary-side control unit 22 indicates that the changed operation mode is the low-frequency side slow-phase mode. Estimated. In this case, the primary side control unit 22 ends the characteristic estimation operation. That is, the value of the capacitance of the primary side capacitor C1 is set to an initial value.

For example, when it is estimated from the first characteristic that the operation mode is the slow phase mode (see FIG. 13B), the primary side control unit 22 increases the capacitance of the primary side capacitor C1 in the second process, and then 3 processes are executed. When it is estimated from the second characteristic estimated by the third process that the operation mode is the slow phase mode again, the primary side control unit 22 estimates that the changed operation mode is the high frequency side slow phase mode. To do. Then, the primary-side control unit 22 sets the capacitance of the primary-side capacitor C1 to be smaller than the initial value so that the operation mode becomes the low-frequency side slow-phase mode, and ends the characteristic estimation operation. On the other hand, when it is estimated from the second characteristic estimated by the third process that the operation mode is the second transition mode or the phase advance mode, the primary side control unit 22 sets the operation mode before the change to the low frequency side. Estimated to be in late phase mode. And the primary side control part 22 returns the capacitance of the primary side capacitor | condenser C1 to an initial value, and complete | finishes characteristic estimation operation | movement.

For example, when it is estimated from the first characteristic that the operation mode is the first transition mode (see FIG. 13C), the primary side control unit 22 increases the capacitance of the primary side capacitor C1 in the second process, and then The third process is executed. If it is estimated from the second characteristic estimated by the third process that the operation mode is the slow phase mode or the second transition mode, the primary side control unit 22 determines that the operation mode before the change is the first on the low frequency side. Estimated to be in transition mode. Then, the primary side control unit 22 sets the capacitance of the primary side capacitor C1 to be larger than the initial value so that the operation mode becomes the low-frequency side slow-phase mode, and ends the characteristic estimation operation. On the other hand, when it is estimated from the second characteristic estimated by the third process that the operation mode is the slow phase mode, the primary side control unit 22 determines that the changed operation mode is the high frequency side slow phase mode. presume. Then, the primary-side control unit 22 sets the capacitance of the primary-side capacitor C1 to be smaller than the initial value so that the operation mode becomes the low-frequency side slow-phase mode, and ends the characteristic estimation operation.

For example, when it is estimated from the first characteristic that the operation mode is the second transition mode (see FIG. 13D), the primary-side control unit 22 is configured so that the operation mode becomes the low-frequency side slow-phase mode. The capacitance of the primary side capacitor C1 is reduced, and the characteristic estimation operation ends.

Next, an example in which the primary control unit 22 determines the inductance value of the primary coil L1 will be described. For example, when it is estimated from the first characteristic that the operation mode is the phase advance mode, the primary side control unit 22 changes the inductance of the primary side coil L1 in the second process, and then executes the third process. And the primary side control part 22 changes the inductance of the primary side coil L1, and complete | finishes a characteristic estimation operation | movement so that an operation mode may be a slow phase mode by the side of a low frequency. In the case of the characteristic estimation operation for changing the inductance of the primary side coil L1, the following may be read in the characteristic estimation operation for changing the capacitance of the primary side capacitor C1. In the case of the characteristic estimation operation for changing the inductance of the primary side coil L1, if “the capacitance of the primary side capacitor C1 is made larger than the initial value” is read as “the inductance of the primary side coil L1 is made smaller than the initial value”. Good. Similarly, “make the capacitance of the primary side capacitor C1 smaller than the initial value” may be read as “make the inductance of the primary side coil L1 larger than the initial value”.

As described above, in the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 as the characteristic estimation unit executes the first process, the second process, and the third process in the characteristic estimation operation. Yes. In the second process, the primary side control unit 22 changes at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 by an amount corresponding to the first characteristic. For this reason, the non-contact electric power feeding system 1 of this embodiment can estimate the frequency characteristic of the primary side LC circuit 24 by characteristic estimation operation | movement, even when the range of the frequency which can be used is restrict | limited.

Furthermore, in the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 sets at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 as a value according to the second characteristic. For this reason, the non-contact power feeding system 1 of the present embodiment changes the frequency characteristics of the primary side LC circuit 24 so that the operation mode becomes the lag mode even when the usable frequency range is limited. Can do.

In the contactless power supply system 1 of the present embodiment, the primary side control unit 22 performs the second process and the third process once each, but may perform the process a plurality of times.

(Embodiment 3)
Hereinafter, the non-contact electric power feeding system 1 which concerns on Embodiment 3 of this invention is demonstrated. In the contactless power supply system 1 of the present embodiment, the description of the components common to the contactless power supply system 1 of the first and second embodiments is omitted as appropriate.

In the contactless power feeding system 1 of the present embodiment, the characteristic estimation operation executed by the primary side control unit 22 is different from that of the contactless power feeding system 1 of the second embodiment. That is, in the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 changes at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 by a predetermined amount in the second process. Yes. Moreover, in the non-contact electric power feeding system 1 of this embodiment, the primary side control part 22 respond | corresponds at least one of the capacitance of the primary side capacitor | condenser C1, and the inductance of the primary side coil L1 according to a 1st characteristic and a 2nd characteristic. Value.

Hereinafter, specific examples will be described. After executing the first process, the primary side control unit 22 reduces the capacitance of the primary side capacitor C1 in the second process, and then executes the third process. And the primary side control part 22 performs a 2nd process and a 3rd process alternately, making the capacitance of the primary side capacitor | condenser C1 small gradually. Thereby, for example, if the frequency characteristic of the primary side LC circuit 24 has two maximum values, the first characteristic and the second characteristic as shown in FIG. 15 are estimated. In FIG. 15, a curve S1 indicates the first characteristic estimated by the first process. In FIG. 15, curves S2 to S5 each indicate the second characteristic estimated by the third process.

In this case, it is estimated that the slow phase mode on the low frequency side is between the second characteristic represented by the curve S2 and the second characteristic represented by the curve S3. Therefore, the primary side control unit 22 places the primary side capacitor C1 so that the usable frequency range is located between the second characteristic represented by the curve S2 and the second characteristic represented by the curve S3. The capacitance is adjusted, and the characteristic estimation operation is terminated.

For example, if the frequency characteristic of the primary side LC circuit 24 has only one maximum value, the first characteristic and the second characteristic as shown in FIG. 16 are estimated. In FIG. 16, a curve S6 shows the first characteristic estimated by the first process. In FIG. 16, curves S7 to S10 each indicate the second characteristic estimated by the third process.

In this case, it is estimated that the slow phase mode is between the second characteristic represented by the curve S8 and the second characteristic represented by the curve S10. Therefore, the primary-side control unit 22 places the primary-side capacitor C1 so that the usable frequency range is located between the second characteristic represented by the curve S8 and the second characteristic represented by the curve S10. The capacitance is adjusted, and the characteristic estimation operation is terminated.

As described above, in the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 as the characteristic estimation unit has at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 in the second process. Is changed by a predetermined amount. For this reason, the non-contact electric power feeding system 1 of this embodiment can estimate the frequency characteristic of the primary side LC circuit 24 by characteristic estimation operation | movement, even when the range of the frequency which can be used is restrict | limited.

Furthermore, in the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 determines at least one of the capacitance of the primary side capacitor C1 and the inductance of the primary side coil L1 according to the first characteristic and the second characteristic. Value. For this reason, the non-contact power feeding system 1 of the present embodiment changes the frequency characteristics of the primary side LC circuit 24 so that the operation mode becomes the lag mode even when the usable frequency range is limited. Can do.

In the non-contact power feeding system 1 of the present embodiment, the primary side control unit 22 alternately executes the second process and the third process a plurality of times, but each of the second process and the third process is 1 It may be executed only once.

In the contactless power feeding system 1 of the second and third embodiments, the effective value Ie of the output current I of the AC power supply 21 is a measured value related to the characteristics of the primary side LC circuit 24, but other values are used. May be. For example, a representative value (a peak value, an average value, etc.) other than the effective value Ie of the output current I of the AC power supply 21 may be used as the measurement value. In addition, the phase difference between the phase of the output current I of the AC power supply 21 and the phase of the output voltage V of the AC power supply 21 may be used as the measurement value. Further, an input current of the AC power source 21 (an input current from the DC power source unit 210 to the inverter unit 211) or an input power of the AC power source 21 may be used as the measurement value.

In the contactless power supply systems 1 of the first to third embodiments, the primary side coil L1 and the secondary side coil L2 may be solenoid type coils or spiral type coils. The solenoid type coil is a coil that is formed in a spiral shape by winding a conducting wire. A spiral type coil is a coil formed by winding a conducting wire in a spiral shape around an arbitrary point, and is also called a circular type coil. The shape of the spiral coil in plan view is not limited to a circular shape, and may be, for example, an elliptical shape or a rectangular shape.

The spiral type coil has the advantage that unnecessary radiation noise is less likely to occur than the solenoid type coil. In addition, the use of the spiral type coil has the advantage that unnecessary radiation noise is reduced and the operating frequency range usable in the inverter unit 211 is expanded. Hereinafter, advantages of the spiral coil will be described.

As described above, the resonance characteristics of the non-contact power feeding systems in Embodiments 1 to 3 change according to the coupling coefficient k between the primary side coil L1 and the secondary side coil L2. For example, in the case of the first embodiment, when the coupling coefficient k is 0.15 or more, the maximum value is generated in two places, and the minimum value is generated between the two maximum values. That is, the resonance characteristic in the non-contact power supply system shows a so-called bimodal characteristic in which two maximum values are generated in the output as shown in FIG. In this resonance characteristic (bimodal characteristic), two “mountains” in which the output becomes maximum are generated at each of the maximum frequency fr1 on the low frequency side and the maximum frequency fr3 on the high frequency side. Between these two “mountains”, a “valley” in which the output is minimized at the frequency fr2 of the minimum value occurs. That is, the frequencies fr1, fr2, and fr3 have a relationship of fr1 <fr2 <fr3. Hereinafter, on the basis of the frequency fr2, a frequency region lower than the frequency fr2 is referred to as a “low frequency region”, and a frequency region higher than the frequency fr2 is referred to as a “high frequency region”.

In such a resonance characteristic (bimodal characteristic), an inverter is provided in each of a low frequency region (a mountain region where the frequency fr1 is a maximum) and a high frequency region (a mountain region where the frequency fr3 is a maximum). A region where the unit 211 operates in the slow phase mode (hereinafter referred to as “slow phase region”) occurs. Therefore, the inverter unit 211 can operate in the slow phase mode regardless of whether the operating frequency f is in the high frequency region or the low frequency region.

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 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 low frequency region, the unnecessary radiation noise generated in the primary coil L1 and the unnecessary radiation noise generated in the secondary coil L2 cancel each other. Noise is reduced. That is, unnecessary radiation noise of the non-contact power feeding system can be reduced when the operating frequency f of the inverter unit 211 is in the low frequency region than when it is in the high frequency region. Therefore, if the operating frequency f of the inverter unit 211 is in the slow phase region (fr1 <f <fr2) in the low frequency region, the inverter unit 211 operates in the slow phase mode and unnecessary radiation noise is reduced.

By the way, the slow phase region of the low frequency region changes in accordance with the coupling coefficient k between the primary side coil L1 and the secondary side coil L2. When a solenoid type coil is employed, the operating frequency f of the inverter unit 211 needs to be stored in a slow phase region that varies according to the coupling coefficient k in order to reduce unnecessary radiation noise of the non-contact power feeding system.

On the other hand, the spiral type coil is less likely to generate unwanted radiation noise than the solenoid type coil. Therefore, when the spiral type coil is employed, unnecessary radiation noise is reduced even when the operating frequency f of the inverter unit 211 is stored in the slow phase region (f> fr3) of the high frequency region as compared with the case where the solenoid type coil is employed. Can be reduced. Therefore, when the spiral type coil is employed, the operating frequency f of the inverter unit 211 may be stored in either the low frequency region or the slow phase region of the high frequency region. The range expands. The slow phase region in the high frequency region also changes according to the coupling coefficient k, but if the operating frequency f of the inverter unit 211 is swept from a sufficiently high frequency to a low frequency side, the operating frequency f becomes the slow phase region in the high frequency region. Pass through. For this reason, the operating frequency f of the inverter unit 211 can be kept in the slow phase region of the high frequency region without complicated control.

Claims

A primary side coil, a primary side capacitor that constitutes a primary side LC circuit together with the primary side coil, an AC power source configured to input AC power to the primary side LC circuit, and a power source control that controls the AC power source And a characteristic estimation unit configured to perform a characteristic estimation operation of estimating the characteristic of the primary side LC circuit,
When starting the AC power supply, the power supply control unit sets the effective value of the output voltage during the start-up period before starting the steady operation of controlling the AC power supply so that the frequency of the output voltage is constant. Lower than during steady operation,
The non-contact power feeding apparatus, wherein the characteristic estimation unit performs the characteristic estimation operation during the start-up period.
The characteristic estimation unit includes:
The frequency of the output voltage of the AC power supply is gradually changed in a predetermined frequency range, and a frequency sweep for detecting a measurement value related to the characteristics of the primary side LC circuit is executed a plurality of times, thereby allowing the primary side LC circuit to A first process for estimating a characteristic in the predetermined frequency range as a first characteristic;
A second process for changing at least one of a capacitance of the primary capacitor and an inductance of the primary coil after the first process;
After the second processing, performing the frequency sweep to execute a third processing for estimating a characteristic of the primary LC circuit in the predetermined frequency range as a second characteristic in the characteristic estimation operation. The contactless power feeding device according to claim 1, wherein
The said characteristic estimation part changes at least one of the capacitance of the said primary side capacitor | condenser and the inductance of the said primary side coil by the quantity according to the said 1st characteristic in the said 2nd process. The non-contact electric power feeder of description.
3. The non-contact power feeding apparatus according to claim 2, wherein the characteristic estimation unit changes at least one of a capacitance of the primary side capacitor and an inductance of the primary side coil by a predetermined amount in the second process. .
5. The non-contact power feeding apparatus according to claim 2, wherein the measured value is an effective value of an output current of the AC power supply.
The non-contact power feeding apparatus according to claim 1, wherein the characteristic estimation unit estimates the characteristic based on a current in the AC power source.
The contactless power supply device according to claim 6, wherein the characteristic estimation unit estimates the characteristic based on a shift between an output voltage phase and an output current phase in the AC power supply.
8. The non-power supply unit according to claim 1, wherein the power supply control unit gradually changes the frequency of the output voltage of the AC power supply while the characteristic estimation operation is performed. Contact power supply device.
The contactless power supply device according to claim 8, wherein the characteristic estimation unit detects the effective value of the output current of the AC power supply a plurality of times in a state where the frequency of the output voltage of the AC power supply is different.
A characteristic adjusting unit that controls at least one of the capacitance of the primary capacitor and the inductance of the primary coil;
The characteristic adjustment unit sets at least one of the capacitance of the primary side capacitor and the inductance of the primary side coil to a value according to the characteristic estimated in the characteristic estimation operation before the steady operation is started. 10. The non-contact power feeding apparatus according to claim 1, wherein a characteristic adjusting operation is performed.
A storage unit that stores in advance a table showing a correspondence relationship between at least one of the capacitance of the primary side capacitor and the inductance of the primary side coil and the characteristic estimated by the characteristic estimation operation;
In the characteristic adjustment operation, the characteristic adjustment unit associates at least one of a capacitance of the primary capacitor and an inductance of the primary coil in the table with respect to the characteristic estimated in the characteristic estimation operation. The contactless power feeding device according to claim 10, wherein the value is a value.
12. The characteristic estimation unit re-estimates the characteristic after the characteristic adjustment unit changes at least one of a capacitance of the primary side capacitor and an inductance of the primary side coil. The non-contact electric power feeder of description.
A non-contact power feeding device according to any one of claims 1 to 12,
A non-contact power supply system comprising: a non-contact power receiving device having a secondary coil configured to induce a current by an electromagnetic field generated by the primary coil.
The non-contact power receiving device has an opening / closing part that opens and closes an electric circuit between both ends of the secondary coil, and a secondary side control part that controls the opening / closing part,
The secondary side control unit turns on the opening / closing unit during a period in which the characteristic estimation operation is performed, and turns off the opening / closing unit in a period in which the steady operation is performed. The contactless power supply system according to claim 13.
The non-contact power receiving device has a rectifying unit that rectifies the output of the secondary coil,
The contactless power feeding system according to claim 14, wherein the opening / closing part is electrically connected between output terminals of the rectifying part.