JP6347389B2 - Non-contact power feeding device, non-contact power receiving device, and non-contact power feeding system - Google Patents

Description

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

  Conventionally, a non-contact power supply device that supplies power from the primary unit to the secondary unit in a non-contact manner has been proposed (see, for example, Patent Document 1).

  The non-contact power supply device includes a secondary unit that rectifies and smoothes the induced current flowing in the secondary winding of the coupling transformer, and converts the output of the rectifying and smoothing circuit into a sinusoidal AC voltage. And an inverter circuit for supplying the load.

JP 2004-96853 A

  In the non-contact power supply device described in Patent Document 1, the rectifying and smoothing circuit converts the induced current flowing in the secondary winding of the coupling transformer into a DC voltage. Therefore, in order to supply the alternating voltage to the load, an inverter circuit that converts the direct current voltage output from the rectifying and smoothing circuit into the alternating current voltage is necessary, and the apparatus becomes large by the amount of provision of the inverter circuit. In the secondary unit, since the inverter circuit converts the DC output of the rectifying / smoothing circuit to AC after the rectifying / smoothing circuit converts the AC output on the secondary side of the coupling transformer to DC, the DC / AC conversion is performed. Loss was generated twice, which was a factor of increasing power loss in the entire apparatus.

  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, a non-contact power reception device, and a non-contact power supply system that are reduced in size while suppressing power loss in the entire non-contact power supply system. And

  The non-contact power feeding device of the present invention is electromagnetically coupled to a power receiving coil included in the non-contact power receiving device and supplies power to the power receiving coil by electromagnetic induction, and is applied to a load from the non-contact power receiving device. An excitation unit that generates an excitation current to be applied to the power supply coil by switching an input voltage in response to a PWM (Pulse Width Modulation) signal whose duty ratio repeatedly increases and decreases with a period of AC voltage. It is characterized by.

  The contactless power receiving device of the present invention is a power receiving coil that is electromagnetically coupled to a power feeding coil included in the contactless power feeding device and receives power from the power feeding coil by electromagnetic induction, and an AC waveform generated in the power receiving coil by electromagnetic induction. And a filter unit for attenuating a frequency component having a frequency higher than the frequency of the AC voltage applied to the load.

  A non-contact power feeding system according to the present invention includes the above-described non-contact power feeding device and the above-described non-contact power receiving device.

  ADVANTAGE OF THE INVENTION According to this invention, the non-contact electric power feeder, the non-contact electric power receiving apparatus, and the non-contact electric power feeding system which achieved size reduction, suppressing the power loss with the whole non-contact electric power feeding system are realizable.

It is a block diagram of this embodiment. It is a circuit diagram of this embodiment. It is a wave form diagram of the sine wave signal in the PWM signal generation part of this embodiment, a reference signal, and a PWM signal. It is a wave form diagram of the AC voltage output from the voltage applied to the feed coil of this embodiment, and a power receiving apparatus. It is a circuit diagram which shows another circuit structure of this embodiment.

  Hereinafter, the non-contact power feeding system according to the present embodiment will be described with reference to the drawings. The configuration described below is merely an example of the present invention. The present invention is not limited to the following embodiments, and various modifications 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.

  FIG. 1 is a block diagram of a contactless power supply system 10 of the present embodiment, and FIG. 2 is a schematic circuit diagram of the contactless power supply system 10 of the present embodiment.

  As shown in FIG. 1, the non-contact power feeding system 10 of the present embodiment includes a non-contact power feeding device (hereinafter referred to as a power feeding device) 20 and a non-contact power receiving device (hereinafter referred to as a power receiving device) 30. Prepare. In the non-contact power feeding system 10 of the present embodiment, for example, the power feeding device 20 is installed on the back side of a construction material (floor, wall, etc.), and the power receiving device 20 is arranged on the front side of the construction material. The power feeding device 20 supplies the power supplied from the AC power supply 100 to the power receiving device 30 in a contactless manner. The power receiving device 30 includes an outlet 33 to which a power plug (not shown) of a load 40 (a general electric device such as a vacuum cleaner or a television receiver) operating with a commercial AC power source is detachably connected. Yes. The power receiving device 30 supplies the power supplied from the power supply device 20 in a contactless manner to the load 40 connected to the outlet unit 33. Therefore, if the power feeding devices 20 are installed at a plurality of locations on the back side of the construction material, the power receiving device 30 is arranged at a position where power can be received from the power feeding device 20 near the load 40 on the front side of the construction material. Power can be supplied from the power receiving device 30 to the load 40.

  The power supply device 20 includes a rectifying / smoothing circuit 21, an excitation circuit 22 (excitation unit), a power supply coil 23, and a control circuit 24 including a PWM signal generation unit 241 (see FIG. 2).

  The rectifying / smoothing circuit 21 rectifies an AC voltage input from an AC power source 100 such as a commercial AC power source with a full-wave rectifier (not shown), and then smoothes the voltage with a capacitor (not shown). Convert to constant DC voltage.

  The excitation circuit 22 switches the input voltage input from the rectifying and smoothing circuit 21 in accordance with a PWM signal whose duty ratio changes with the period of the AC voltage V2 supplied from the power receiving device 30 to the load 40, thereby supplying the feeding coil. An excitation current to be applied to 23 is generated.

  The power feeding coil 23 is electromagnetically coupled to a power receiving coil 31 provided in the power receiving device 30 and supplies power to the power receiving coil 31 by electromagnetic induction.

  The control circuit 24 controls the operation of the excitation circuit 22.

  The power receiving device 30 includes a power receiving coil 31 and a filter circuit 32. The power receiving device 30 according to the present embodiment further includes an outlet portion 33.

  The power reception coil 31 is electromagnetically coupled to a power supply coil 23 included in the power supply device 20 and receives power from the power supply coil 23 by electromagnetic induction.

  The filter circuit 32 attenuates a frequency component having a frequency higher than the frequency of the AC voltage V <b> 2 supplied to the load 40 from the AC waveform generated in the power receiving coil 31 by electromagnetic induction. The output voltage of the filter circuit 32 is applied to the load 40 connected to the outlet unit 33 via the outlet unit 33.

  Next, specific configurations of the excitation circuit 22, the control circuit 24, and the filter circuit 32 will be described with reference to the circuit diagram of FIG.

  The excitation circuit 22 includes four switching elements 221 to 224. The switching elements 221 to 224 are composed of, for example, field effect transistors, and the switching elements 221 to 224 are controlled to be turned on / off by the control circuit 24. Here, the series circuit of the switching elements 221, 222 and the series circuit of the switching elements 223, 224 are connected in parallel between the output terminals of the rectifying / smoothing circuit 21, and the excitation circuit 22 is an inverter circuit having a full bridge configuration. It consists of The feeding coil 23 is electrically connected between a connection point P1 of the switching elements 221 and 222 and a connection point P2 of the switching elements 223 and 224.

  The control circuit 24 includes a PWM signal generator 241 and a NOT gate 242.

  The PWM signal generation unit 241 generates a PWM signal S3 in which the duty ratio repeatedly increases and decreases in the cycle of the AC voltage V2 supplied from the power receiving device 30 to the load 40. The duty ratio of the PWM signal S3 is periodically increased and decreased according to a constant change pattern in the period of the AC voltage V2.

  The PWM signal generation unit 241 includes a sine wave generation circuit 243, a triangular wave generation circuit 244, and a comparator 245.

  The sine wave generation circuit 243 generates a sine wave signal S1 having a frequency that is substantially the same as the AC voltage V2 (for example, the frequency of a commercial AC power supply, 50 Hz or 60 Hz).

  The triangular wave generation circuit 244 generates a reference signal S2 that is a triangular wave signal having a frequency higher than that of the sine wave signal S1 and a peak value of the signal that is slightly larger than that of the sine wave signal S1. The frequency of the reference signal S2 only needs to be twice or more the frequency of the sine wave signal S1, and is set to about 5 times in this embodiment.

  The comparator 245 compares the signal level of the sine wave signal S1 with the level of the reference signal S2 that is a triangular wave signal. Here, the sine wave signal S <b> 1 is input to the minus input terminal of the comparator 245, and the reference signal S <b> 2 is input to the plus input terminal of the comparator 245. Therefore, as shown in FIG. 3, during the period in which the signal level of the sine wave signal S1 is higher than the signal level of the reference signal S2, the signal level of the PWM signal S3 output from the comparator 245 becomes a low level. During a period in which the signal level of the sine wave signal S1 is lower than the signal level of the reference signal S2, the signal level of the PWM signal S3 is high. Therefore, the PWM signal S3 is a duty signal whose duty ratio repeatedly increases and decreases in the cycle T1 of the sine wave signal S1, and the larger the difference between the reference signal S2 and the sine wave signal S1, the larger the ratio of the on period. The duty signal is as follows.

  The PWM signal S3 output from the comparator 245 is input to the control electrodes of the switching elements 221 and 224, respectively. The PWM signal S3 is input to the NOT gate 242, and the output signal of the NOT gate 242 is input to the control electrodes of the switching elements 222 and 223, respectively. That is, a signal obtained by inverting the high / low of the PWM signal S3 is input to the control electrodes of the switching elements 222 and 223.

  During the period when the signal level of the PWM signal S3 is high, the switching elements 221 and 224 are turned on, the switching elements 222 and 223 are turned off, and a current flows from the rectifying / smoothing circuit 21 to the switching element 221 → the feeding coil 23 → the switching element 224. Flows. On the other hand, during the period when the signal level of the PWM signal S3 is low, the switching elements 221 and 224 are turned off and the switching elements 222 and 223 are turned on, and the path from the rectifying and smoothing circuit 21 to the switching element 223 → the feeding coil 23 → the switching element 222. Current flows. Therefore, an alternating current is applied to the feeding coil 23 by alternately turning on / off the group of switching elements 221 and 224 and the group of switching elements 222 and 223, and an exciting current around the feeding coil 23. Magnetic flux is generated according to the time change.

  On the other hand, the filter circuit 32 included in the power receiving device 30 includes an LC filter circuit using the power receiving coil 31 and a capacitor 321 connected between both ends of the power receiving coil 31. The LC filter circuit using the power receiving coil 31 and the capacitor 321 is a low-pass filter circuit, and attenuates a frequency component higher in frequency than the frequency of the AC voltage V2 applied to the load 40. In the present embodiment, the power receiving coil 31 also serves as the inductor of the LC filter circuit, but the inductor and the capacitor 321 provided separately from the power receiving coil 31 may constitute the LC filter circuit. The filter circuit 32 is not limited to the LC filter circuit, and may be an RC series circuit using a resistor and a capacitor as long as it is a filter circuit that attenuates a frequency component higher than the frequency of the AC voltage V2. Other filter circuits may be used.

  The terminals on both sides of the capacitor 321 are electrically connected to the outlet unit 33, and the voltage across the capacitor 321 (that is, the output voltage of the filter circuit 32) is applied to the load 40 via the outlet unit 33.

  Next, operation | movement of the non-contact electric power feeding system 10 of this embodiment is demonstrated. The power receiving device 30 is disposed at a position where the power receiving coil 31 is magnetically coupled to the power feeding coil 23 and can receive power from the power feeding device 20 in a contactless manner.

  The rectifying / smoothing circuit 21 rectifies and smoothes the AC voltage input from the AC power supply 100, converts the voltage to a DC voltage having a constant voltage value, and outputs the DC voltage to the excitation circuit 22. In the PWM signal generator 241, the sine wave signal S1 is input to the negative input terminal of the comparator 245, and the reference signal S2 is input to the positive input terminal of the comparator 245. The comparator 245 performs PWM such that the duty ratio periodically changes in the cycle of the AC voltage V2 by switching the output signal level to high or low according to the level of the sine wave signal S1 and the reference signal S2. Signal S3 is generated. The PWM signal S3 is input to the control electrodes of the switching elements 221 and 224, and a signal obtained by inverting high / low of the PWM signal S3 (output signal of the NOT gate 242) is input to the switching elements 222 and 223.

  During the period when the signal level of the PWM signal S3 is high, the switching elements 221 and 224 are turned on, the switching elements 222 and 223 are turned off, and a current flows through the feeding coil 23 from the connection point P1 to the connection point P2. On the other hand, during the period when the signal level of the PWM signal S3 is low, the switching elements 221 and 224 are turned off and the switching elements 222 and 223 are turned on, and current flows from the connection point P2 to the connection point P1. Flowing. As shown in FIG. 3, the PWM signal S <b> 3 is a signal that repeatedly increases and decreases according to the same change pattern with the same duty ratio at the same cycle T <b> 1 as the cycle of the AC voltage V <b> 2. Therefore, as shown in FIG. 4, the voltage V1 applied from the excitation circuit 22 to the feeding coil 23 is a positive constant voltage when the PWM signal S3 is high, and is negative when the PWM signal S3 is low. The pulse voltage of the rectangular wave is a constant voltage. At this time, the current flowing through the feeding coil 23 changes according to the voltage V <b> 1, and a magnetic flux corresponding to the current change is generated around the feeding coil 23.

  Here, if the power receiving coil 31 of the power receiving device 30 exists in the vicinity of the power feeding coil 23, a magnetic flux is generated around the power feeding coil 23, whereby a current flows through the power receiving coil 31 by electromagnetic induction. The AC waveform generated in the power receiving coil 31 has a frequency component higher than the frequency of the AC voltage V2 (frequency component of the PWM signal S3). This high frequency component is constituted by the power receiving coil 31 and the capacitor 321. It is attenuated by a low-pass filter. Therefore, the AC voltage V2 output from the filter circuit 32 becomes a sine wave AC voltage after the high frequency component is attenuated as shown in FIG. 4, and this AC voltage V2 is applied to the load 40. That is, since the AC voltage V2 similar to the power supply voltage of the commercial AC power supply is applied to the load 40, the load 40 that operates upon receiving the supply of the commercial AC power supply can be operated.

  By the way, in the non-contact electric power feeding system of the said embodiment, although the excitation circuit 22 is comprised by the full bridge inverter circuit, as shown in FIG. 5, the excitation circuit 22 may be comprised by the half bridge inverter circuit. 5 includes a battery 25 and a smoothing circuit 26 instead of the rectifying and smoothing circuit 21 that converts an alternating voltage input from the alternating current power supply 100 into a direct current. Since the configuration other than the excitation circuit 22, the battery 25, and the smoothing circuit 26 is the same as that of the non-contact power feeding system 10 shown in FIG. 2, the same components are denoted by the same reference numerals and the description thereof is omitted. To do.

  The power feeding device 20 shown in FIGS. 1 and 2 obtains power from an external AC power supply 100, but the power feeding device 20 shown in FIG. 5 obtains power from a built-in battery 25. The battery 25 may be a primary battery, or may be a secondary battery such as a lead storage battery, a nickel hydride battery, or a lithium ion battery, and a battery with a storage amount corresponding to the amount of power supplied to the load 40 may be used.

  The smoothing circuit 26 smoothes the output voltage of the battery 25 and outputs it to the excitation circuit 22.

  The excitation circuit 22 is a half-bridge inverter circuit including two switching elements 225 and 226 and two capacitors 227 and 228. Between the output terminals of the smoothing circuit 26, a series circuit of two switching elements 225 and 226 and a series circuit of two capacitors 227 and 228 are connected in parallel. The feeding coil 23 is connected between a connection point P3 of the switching elements 225 and 226 and a connection point P4 of the capacitors 227 and 228. The switching elements 225 and 226 are composed of, for example, field effect transistors, and the switching elements 225 and 226 are controlled to be turned on / off by the control circuit 24. The PWM signal S3 generated by the PWM signal generator 241 is input to the control electrode of the switching element 225 on the high potential side. A signal obtained by inverting the high / low of the PWM signal S3 by the NOT gate 242 is input to the control electrode of the switching element 226 on the low potential side.

  During the period when the PWM signal S3 is high, the switching element 225 is turned on and the switching element 226 is turned off. A current flows from the smoothing circuit 26 to the feeding coil 23 through the path of the switching element 225 → the feeding coil 23 → the capacitor 228. Capacitor 228 is charged. During the period in which the PWM signal S3 is low, the switching element 225 is turned off, the switching element 226 is turned on, the capacitor 228 is discharged, and the feeding coil passes through the path of the capacitor 228 → the feeding coil 23 → the switching element 226 → the capacitor 228. A current flows through 23.

  Accordingly, when the switching elements 225 and 226 are alternately turned on / off according to the high / low of the PWM signal S3, an alternating current is applied to the feeding coil 23, and the excitation current changes with time around the feeding coil 23. Magnetic flux corresponding to Accordingly, power is supplied from the power feeding coil 23 to the power receiving coil 31 by electromagnetic induction, and power is supplied from the power receiving device 30 to the load 40.

  As described above, the power supply device 20 according to the present embodiment includes the power supply coil 23 and the excitation circuit 22 (excitation unit). The power feeding coil 23 is electromagnetically coupled to a power receiving coil 31 provided in the power receiving device 30 and supplies power to the power receiving coil 31 by electromagnetic induction. The excitation circuit 22 is an excitation that is applied to the feeding coil 23 by switching the input voltage in accordance with the PWM signal S3 whose duty ratio repeatedly increases and decreases in the period of the AC voltage V2 applied from the power receiving device 30 to the load 40. Generate current.

  Thus, the excitation circuit 22 generates the excitation current by switching the input voltage in accordance with the PWM signal S3 whose duty ratio repeatedly increases and decreases in the cycle of the AC voltage V2. As a result, an exciting current whose polarity is reversed according to the high / low of the PWM signal S3 flows in the power supply coil 23, and an alternating current corresponding to the exciting current flows in the power receiving coil 31 by electromagnetic induction. become. Therefore, the power receiving device 30 can obtain the AC voltage V2 having a desired frequency by attenuating the frequency component higher than the frequency of the AC voltage V2 from the AC component generated in the power receiving coil 31 by the filter circuit 32. It can receive power without contact. Therefore, unlike the conventional power receiving apparatus, it is not necessary to perform the operation of converting the AC output of the power receiving coil 31 to DC once and then converting it to the AC voltage V2 having a desired frequency, so that no DC / AC conversion loss occurs. The power loss can be reduced as a whole system. In addition, since it is not necessary to provide the power receiving device 30 with a conversion circuit that converts the AC output of the power receiving coil 31 into direct current and then converts it into the AC voltage V2 having a desired frequency, the power receiving device 30 is reduced in size by the conversion circuit. There is also an advantage of being able to do it.

  Further, the power supply apparatus 20 of the present embodiment may include a PWM signal generation unit 241 that generates the PWM signal S3. The PWM signal generation unit 241 has a signal level of the sine wave signal S1 having the same period as the AC voltage V2 applied from the power receiving device 30 to the load 40, and a signal level of the reference signal S2 having a higher frequency than the sine wave signal S1. The PWM signal S3 is generated by comparing the levels. As a result, the PWM signal generator 241 can generate the PWM signal S3 such that the duty ratio repeatedly increases and decreases in the cycle of the AC voltage V2 applied to the load 40. When the excitation circuit 22 switches the input voltage according to the PWM signal S3, an excitation current whose polarity is inverted according to the high / low of the PWM signal S3 can be supplied to the feeding coil 23.

  The power receiving device 30 of this embodiment includes a power receiving coil 31 and a filter circuit 32 (filter unit). The power reception coil 31 is electromagnetically coupled to a power supply coil 23 included in the power supply device 20 and receives power from the power supply coil 23 by electromagnetic induction. The filter circuit 32 attenuates a frequency component having a frequency higher than the frequency of the AC voltage V <b> 2 applied to the load 40 from the AC waveform generated in the power receiving coil 31 by electromagnetic induction.

  In this way, the filter circuit 32 applies the AC voltage V2 having a desired frequency to the load 40 by attenuating a frequency component having a frequency higher than the frequency of the AC voltage V2 from the AC waveform generated in the power receiving coil 31. Can do. In addition, the power receiving device 30 does not perform the operation of converting the AC output of the power receiving coil 31 into direct current after converting it into direct current as in the conventional example, so that a conversion loss between direct current and alternating current does not occur. Therefore, power loss can be reduced as a whole system. In addition, the power receiving device 30 includes only the filter circuit 32 and does not include a conversion circuit that converts the AC output of the power receiving coil 31 into direct current and then converts it into the AC voltage V2 having a desired frequency. There is also an advantage that the device 30 can be miniaturized.

  In the power receiving device 30 of the present embodiment, the filter circuit 32 may be an LC filter circuit including a power receiving coil 31 and a capacitor 321.

  Since the inductor of the LC filter circuit is also used as the power receiving coil 31, the number of parts can be reduced and the overall size can be reduced.

  The contactless power supply system of the present embodiment includes any one of the power supply devices 20 described above and any one of the power reception devices 30 described above, and is a compact contactless power supply that reduces power loss as a whole system. A system can be realized.

10 Non-contact power supply system 20 Power supply device (Non-contact power supply device)
21 Rectification smoothing circuit 22 Excitation circuit (excitation part)
23 Power Supply Coil 241 PWM Signal Generator 30 Power Receiving Device (Non-Contact Power Receiving Device)
31 Receiving coil 32 Filter circuit (filter part)
321 Capacitor 40 Load S1 Sine wave signal S2 Reference signal (triangular wave signal)
S3 PWM signal V2 AC voltage

Claims (5)

A power supply coil that is electromagnetically coupled to a power receiving coil included in the non-contact power receiving device and supplies power to the power receiving coil by electromagnetic induction;
An excitation unit that generates an excitation current to be applied to the power feeding coil by switching an input voltage in accordance with a PWM signal whose duty ratio repeatedly increases and decreases in a cycle of an AC voltage applied to a load from the non-contact power receiving device And a non-contact power feeding device. By comparing the signal level of a sine wave signal having the same period as the AC voltage applied to the load from the non-contact power receiving device and the signal level of a triangular wave signal having a frequency higher than the frequency of the sine wave signal, The non-contact power feeding apparatus according to claim 1, further comprising a PWM signal generation unit that generates the PWM signal.   The non-contact power feeding device according to claim 1, and the non-contact power receiving device that receives power from the non-contact power feeding device in a non-contact manner.
  A non-contact power feeding system characterized by that.   The contactless power receiving device included in the contactless power feeding system according to claim 3,
  The power receiving coil that is electromagnetically coupled to the power feeding coil provided in the non-contact power feeding device and receives power from the power feeding coil by electromagnetic induction; and
  A filter unit for attenuating a frequency component having a frequency higher than the frequency of the AC voltage applied to the load from an AC waveform generated in the power receiving coil by electromagnetic induction;
  A non-contact power receiving device.   The filter unit is an LC filter circuit including the power receiving coil and a capacitor.
  The non-contact power receiving device according to claim 4.

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