JP2014011845A - Noncontact power transmission device and power receiving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noncontact power transmission device and a power receiving apparatus in which impedance adjustment can be carried out suitably.SOLUTION: A noncontact power transmission device 10 includes a ground side apparatus 11 provided on the ground, and a vehicle side apparatus 21 provided in a vehicle. The ground side apparatus 11 is provided with a high frequency power supply 12, and a transmitter 13 having a primary coil 13a. The vehicle side apparatus 21 is provided with a power receiver 23 having a secondary coil 23a, and a battery 22 for vehicle connected with the power receiver 23 via a rectifier 24. The rectifier 24 includes a diode bridge, and a DC bias power supply for applying a DC bias voltage to a positive side diode constituting a diode bridge.

Description

  The present invention relates to a non-contact power transmission device and a power receiving device.

  2. Description of the Related Art Conventionally, as a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, a device using magnetic field resonance is known. For example, the non-contact power transmission device of Patent Literature 1 includes a power transmission device provided with an AC power source and a primary resonance coil to which AC power is input from the AC power source. Further, the power receiving device mounted on the electric vehicle is provided with a primary side resonance coil and a secondary side resonance coil capable of magnetic field resonance. Then, AC power is transmitted from the power transmitting device to the power receiving device due to magnetic field resonance between the primary side resonance coil and the secondary side resonance coil. The transmitted AC power is rectified to DC power by a rectifier provided in the power receiving device. Then, the rectified DC power is input to the battery as a load connected to the output terminal of the rectifier, whereby the battery is charged.

JP 2009-106136 A

  Here, since the impedance may vary depending on the distance between the coils and the power value of the power input to the battery, impedance adjustment may be performed when charging is performed in order to increase transmission efficiency. In this case, impedance adjustment may be performed by transmitting AC power having a power value smaller than the power value of AC power transmitted when charging, but the power value of AC power output from the AC power source is small. In some cases, the power value of the AC power input to the rectifier becomes small and the rectifier does not operate. Then, the impedance of the battery connected to the output terminal of the rectifier is not reflected. For this reason, accurate impedance measurement cannot be performed, and the accuracy of impedance adjustment is reduced. However, if the power value of the AC power output from the AC power supply is increased in order to secure a power value sufficient for the rectifier to operate, there is a concern that the power consumption related to the impedance adjustment increases. Moreover, there is a concern that the reflected power to the AC power supply increases and the burden on the AC power supply increases.

Note that the above situation is not limited to the case where power transmission is performed by magnetic field resonance, and the same situation occurs in the case where power transmission is performed by electromagnetic induction.
This invention is made | formed in view of the situation mentioned above, Comprising: It aims at providing the non-contact electric power transmission apparatus and power receiving apparatus which can perform an impedance adjustment suitably.

  In order to achieve the above object, the invention according to claim 1 includes an AC power source that outputs AC power, a power transmission device having a primary coil to which the AC power is input from the AC power source, and the primary side. In a non-contact power transmission device comprising a secondary coil capable of receiving the AC power in a non-contact manner from a coil and a power receiving device having a load, the operation is performed when a voltage exceeding a predetermined threshold voltage is applied. A rectifying unit that rectifies AC power received by the secondary coil using the semiconductor element into DC power, and the DC power can be input to the load. Yes, provided in at least one of the power transmitting device and the power receiving device, impedance adjusting means for adjusting impedance, and provided in the power receiving device, at least the impedance adjustment Characterized in that it comprises a bias voltage applying means for applying said threshold voltage above the bias voltage to the semiconductor device in the case of performing.

  According to this invention, by applying a bias voltage to the semiconductor element, the semiconductor element operates regardless of the power value of the AC power input to the rectifying unit. Thereby, even if the power value of the AC power input to the rectifier is small, the AC power can be rectified by the rectifier and input to the load. Therefore, the impedance from the input of the rectifying unit to the load can be grasped. Therefore, highly accurate impedance adjustment can be performed in a situation where the power value of the AC power output from the AC power supply is small. Therefore, in the impedance adjustment, both improvement in accuracy and reduction in power consumption can be achieved, and the burden on the AC power supply can be reduced through reduction of reflected power.

  According to a second aspect of the present invention, the AC power supply is configured to be capable of outputting the first AC power and the second AC power having a power value larger than the first AC power, and at least performing the impedance adjustment. Outputs the first AC power, and the load is a variable load having different impedance depending on the power value of the input DC power, and is provided between the rectifying unit and the variable load. The fixed load having an impedance corresponding to the impedance when the DC power when the second AC power is output from the AC power source is input to the variable load, and the connection destination of the rectifying unit is the variable load. And the connection switching means for switching to the fixed load, and when the impedance adjustment is performed, the connection switching is performed so that the connection destination of the rectifying unit is the fixed load. Characterized by comprising control means for controlling the stage, the.

  According to this invention, when impedance adjustment is performed, it is possible to reduce power loss or the like related to impedance adjustment by outputting the first AC power having a relatively small power value. On the other hand, when DC power is input to the variable load in earnest, the second AC power can be used to input DC power to the variable load.

  Here, the impedance of the variable load varies depending on the power value of the input DC power. For this reason, if impedance adjustment is performed in the state in which the first AC power is output from the AC power supply, then the second AC power is output from the AC power supply, impedance adjustment cannot be obtained.

  On the other hand, according to the present invention, when impedance adjustment is performed, a fixed load is connected to the rectifying unit. The impedance of the fixed load corresponds to the impedance when the DC power when the second AC power is output from the AC power source is input to the variable load. Thereby, in the situation where the 1st AC power is outputted, the situation where the DC power concerning the 2nd AC power is inputted into the variable load can be created virtually. Therefore, in a configuration in which a variable load is provided, impedance adjustment can be performed when the second AC power is output using the first AC power. Therefore, the above inconvenience can be avoided.

  According to a third aspect of the present invention, the power receiving device applies the bias voltage to the semiconductor element when the impedance adjustment is performed, and does not apply the bias voltage to the semiconductor element when the impedance adjustment is not performed. It is characterized by comprising bias switching means that operate in the same manner. According to this invention, since the bias voltage is applied only when necessary, wasteful power consumption by the bias voltage applying means can be suppressed. Further, it is possible to avoid a situation in which the DC power output from the rectifying unit is deviated from a desired value due to the application of the bias voltage when power transmission is performed.

  The invention according to claim 4 is characterized in that the power receiving device is mounted on a vehicle, and the load is a vehicle battery. According to this invention, the DC power rectified by the rectifier is used for charging the vehicle battery. Here, the vehicle battery is required to have a large storage capacity compared to a battery such as a mobile phone. For this reason, as a non-contact electric power transmission apparatus, the electric power of a very big electric power value is handled. Therefore, power loss and heat generation due to low accuracy of impedance adjustment cannot be ignored, and power consumption and reflected power related to impedance adjustment cannot be ignored.

  In this regard, as described above, by applying a bias voltage to the semiconductor element, it is possible to realize highly accurate impedance adjustment with AC power having a small power value. Thereby, the non-contact electric power transmission apparatus (non-contact charging apparatus) suitable for charge of the battery for vehicles which can handle high electric power suitably can be provided.

  According to a fifth aspect of the present invention, in the power receiving device, a secondary coil capable of receiving the AC power in a non-contact manner from a power transmitting device having a primary coil to which AC power is input, and a predetermined threshold voltage or higher. A rectifying unit that rectifies AC power received by the secondary coil using the semiconductor element into DC power, and rectified by the rectifying unit. A load to which the direct-current power can be input; impedance adjusting means for adjusting impedance; and bias voltage applying means for applying a bias voltage equal to or higher than the threshold voltage to the semiconductor element when performing impedance adjustment at least. It is characterized by providing.

  According to this invention, by applying a bias voltage to the semiconductor element, the semiconductor element operates regardless of the power value of the AC power input to the rectifying unit. Thereby, even if the power value of the AC power input to the rectifier is small, the AC power can be rectified by the rectifier and input to the load. Therefore, the impedance from the input of the rectifying unit to the load can be grasped. Therefore, highly accurate impedance adjustment can be performed in a situation where the power value of the AC power output from the AC power supply is small. Therefore, in the impedance adjustment, both improvement in accuracy and reduction in power consumption can be achieved.

  According to the present invention, impedance adjustment can be suitably performed.

The block diagram which shows the electrical constitution of the non-contact electric power transmission apparatus which concerns on this invention. The circuit diagram of a rectifier.

Hereinafter, an embodiment of a non-contact power transmission apparatus (non-contact power transmission system) according to the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the non-contact power transmission device 10 includes a ground-side device 11 provided on the ground and a vehicle-side device 21 mounted on the vehicle. The ground side device 11 corresponds to a power transmission (primary side) device, and the vehicle side device 21 corresponds to a power reception (secondary side) device.

  The ground-side device 11 includes a high-frequency power source 12 (AC power source) capable of outputting high-frequency power (AC power) having a predetermined frequency and a power transmitter 13. The high frequency power supply 12 is configured to be able to supply high frequency power having different power values. High frequency power is input to the power transmitter 13 from the high frequency power source 12. The vehicle-side device 21 includes a vehicle battery 22 and a power receiver 23 that can receive high-frequency power from the power transmitter 13.

  The power transmitter 13 and the power receiver 23 are configured to be capable of magnetic field resonance. Specifically, the power transmitter 13 includes a resonance circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The power receiver 23 is composed of a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel. Both resonance frequencies are set to be the same.

  The vehicle-side device 21 is provided with a rectifier 24 that rectifies high-frequency power received by the power receiver 23 into DC power. As shown in FIG. 2, the input terminal 24 a of the rectifier 24 is connected to the power receiver 23. Between the output terminal 24b of the rectifier 24 and the vehicle battery 22, a fixed resistor that is arranged in parallel with the vehicle battery 22 and has a constant resistance value (impedance) even if the power value of the input DC power changes. 25 (fixed load) is provided. Further, a changeover switch 26 is provided between the output terminal 24 b of the rectifier 24 and the vehicle battery 22 to switch the connection destination of the rectifier 24 (DC power input destination) between the vehicle battery 22 and the fixed resistor 25. ing. When the rectifier 24 and the vehicle battery 22 are connected by the changeover switch 26, the DC power rectified by the rectifier 24 is input to the vehicle battery 22.

  Incidentally, the vehicle battery 22 is a variable load that appears to have different impedances depending on the power value of the input DC power. For this reason, the impedance of the vehicle battery 22 differs according to the power value of the high-frequency power output from the high-frequency power source 12.

  As shown in FIG. 1, the ground side device 11 is provided with a power source side controller 14 for controlling the high frequency power source 12 and the like. The vehicle-side device 21 is provided with a vehicle-side controller 27 that controls the rectifier 24 and the changeover switch 26. The vehicle side controller 27 is connected to the power source side controller 14 so as to be capable of wireless communication. Therefore, the controllers 14 and 27 can exchange information.

  The vehicle-side controller 27 transmits a chargeable signal to the power-side controller 14 when the vehicle is arranged at a position where charging is possible, specifically, a position where the power transmitter 13 and the power receiver 23 can be magnetically resonated. When receiving the chargeable signal, the power supply side controller 14 performs impedance adjustment, and starts charging after the impedance adjustment is completed.

  The configuration relating to the impedance adjustment will be described. The ground side device 11 is provided with an impedance measuring device 15 for measuring the impedance from the output end of the high frequency power source 12 to the vehicle battery 22. The impedance measuring instrument 15 measures the impedance in response to a request from the power supply side controller 14 and transmits the measurement result to the power supply side controller 14.

  In the ground-side device 11, an impedance adjuster 16 is provided between the high-frequency power source 12 and the power transmitter 13. The impedance adjuster 16 performs impedance adjustment based on the measurement result by the impedance measuring instrument 15. The impedance adjuster 16 is configured such that at least one of capacitance and inductance is variably configured. Specifically, the impedance adjuster 16 includes an inductor and a variable capacitor. The power supply side controller 14 adjusts the impedance by variably controlling the capacitance of the variable capacitor of the impedance adjuster 16 based on the impedance measured by the impedance measuring device 15.

Next, the configuration of the rectifier 24 will be described in detail.
As shown in FIG. 2, the rectifier 24 includes a diode bridge 31 that performs full-wave rectification on the high-frequency power received by the power receiver 23, and a smoothing circuit 32 that smoothes the full-wave rectified power. The diode bridge 31 is connected to the input terminal 24 a of the rectifier 24, and the smoothing circuit 32 is connected to the output side of the diode bridge 31 and is connected to the output terminal 24 b of the rectifier 24.

  The diode bridge 31 has a plurality of positive-side diodes 31a used to transmit the positive component of the high-frequency power to the smoothing circuit 32, and a plurality of diodes 31 used to invert the negative component of the high-frequency power and transmit it to the smoothing circuit 32. It comprises a negative side diode 31b. The smoothing circuit 32 includes a smoothing capacitor 32a and a choke coil 32b. The smoothing capacitor 32 a is connected in parallel to the output from the diode bridge 31, and the choke coil 32 b is connected in series to the output from the diode bridge 31.

  The rectifier 24 includes a DC bias power supply 33 that applies a DC bias voltage that allows the positive-side diode 31a to operate. Specifically, the DC bias voltage is set to be the same as the forward threshold voltage of the positive diode 31a.

  Further, the rectifier 24 includes a switching element 34 as bias switching means connected in series to a DC bias power source 33. The switching element 34 performs an on / off operation based on a control signal from the vehicle-side controller 27.

  An inductor 35 is provided on both sides of the DC bias power supply 33. The inductor 35 prevents the capacitance component of the DC bias power supply 33 from being included in the impedance of the rectifier 24 when the switching element 34 is turned on.

  Here, as shown in FIG. 1 and FIG. 2, when the power supply side controller 14 starts the impedance adjustment based on the reception of the charging start signal, the power controller 14 has a power value smaller than the power value of the charging high-frequency power. The high frequency power supply 12 is controlled so that high frequency power for impedance adjustment is output, and the impedance measuring device 15 is requested to measure impedance. Then, the power supply side controller 14 transmits information (first information) indicating that the impedance adjustment is started to the vehicle side controller 27. When the information is received, the vehicle-side controller 27 transmits a control signal so that the switching element 34 is turned on, and controls the changeover switch 26 so that the connection destination of the rectifier 24 is the fixed resistor 25.

  Here, the resistance value (impedance) of the fixed resistor 25 is set in correspondence with the impedance of the vehicle battery 22 when the charging high-frequency power is output. Specifically, the resistance value of the fixed resistor 25 is the vehicle battery when the charging DC power obtained by rectifying the charging high-frequency power input to the rectifier 24 is input to the vehicle battery 22. 22 is set to the same impedance. More specifically, when the voltage of the vehicle battery 22 is a battery voltage, the resistance value of the fixed resistor 25 is set to a value obtained by dividing the square of the battery voltage by the DC power for charging.

  After that, when the impedance adjustment is completed (terminated), the power supply side controller 14 controls the high frequency power supply 12 so that the high frequency power for charging is output instead of the high frequency power for impedance adjustment, and the impedance adjustment is completed. Information indicating the fact (second information) is transmitted to the vehicle-side controller 27. When the information is received, the vehicle-side controller 27 transmits a control signal so that the switching element 34 is turned off, and controls the changeover switch 26 so that the connection destination of the rectifier 24 is the vehicle battery 22. In addition, the function which controls the switching element 34 and the changeover switch 26 in the vehicle side controller 27 respond | corresponds to a control means.

  As shown in FIG. 2, a capacitor 41 is connected in series between the power receiver 23 and the rectifier 24. This restricts the direct current power of the DC bias power supply 33 from flowing to the power receiver 23 side.

A series of operation | movement and effect | actions in the non-contact electric power transmission apparatus 10 of this embodiment are demonstrated.
When the vehicle is disposed at a position where it can be charged, a chargeable signal is transmitted from the vehicle-side controller 27 to the power-side controller 14. Thereby, impedance adjustment is started. Specifically, high frequency power for impedance adjustment is output from the high frequency power source 12. Then, the switching element 34 of the rectifier 24 is turned on, and the connection destination of the rectifier 24 is the fixed resistor 25. As a result, a DC bias voltage is applied to the positive-side diode 31a, the positive-side diode 31a operates, and high-frequency power for impedance adjustment is input to the fixed resistor 25.

  In this case, the state in which the rectifier 24 is operating is virtually realized. The power (DC power) output from the rectifier 24 is input to the fixed resistor 25. The resistance value of the fixed resistor 25 is set in correspondence with the impedance of the vehicle battery 22 when charging power is input. For this reason, the situation where the DC power for charging is input to the vehicle battery 22 is virtually realized. Thereby, the impedance measuring device 15 measures the accurate impedance including the impedance from the input terminal 24a of the rectifier 24 to the vehicle battery 22. Then, the impedance adjuster 16 performs impedance adjustment based on the accurately measured impedance.

  When the impedance adjustment is completed, charging high-frequency power is output from the high-frequency power supply 12 and information indicating that the impedance adjustment is completed is transmitted to the vehicle-side controller 27. Thereby, the switching element 34 is turned off, the application of the DC bias voltage is stopped, and the connection destination of the rectifier 24 is switched to the vehicle battery 22. Therefore, charging of the vehicle battery 22 is started.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) A DC bias power source 33 that applies the same DC bias voltage as the threshold voltage of the positive side diode 31a to the positive side diode 31a used for rectification of the high frequency power received by the power receiver 23 is provided. Thereby, even when the power value of the high-frequency power for impedance adjustment output when performing impedance adjustment is small, the state in which the rectifier 24 operates can be virtually realized. Therefore, even when the power value of the high frequency power for impedance adjustment is small, accurate impedance including the impedance from the input terminal 24a of the rectifier 24 to the vehicle battery 22 can be measured. Impedance adjustment can be performed. Therefore, it is possible to achieve both improvement in accuracy in impedance adjustment and reduction in power consumption, and it is possible to reduce the burden on the high-frequency power source 12 through suppression of reflected power in impedance adjustment.

  Here, the structure which grasps | ascertains the impedance from the input terminal 24a of the rectifier 24 to the vehicle battery 22 as a predetermined fixed value is also considered. However, since the impedance of the vehicular battery 22 varies depending on the input DC power value, the configuration that is grasped as a fixed value cannot perform high-precision impedance adjustment. On the other hand, according to this embodiment, the impedance adjustment corresponding to the fluctuation | variation of the impedance of the vehicle battery 22 can be performed with low power consumption.

  In the non-contact power transmission device 10, when the distance between the coils 13 a and 23 a varies, the mutual inductance varies, and the impedance from the input end of the impedance adjuster 16 to the vehicle battery 22 varies. Then, depending on the distance between the coils 13a and 23a, the transmission efficiency is low unless impedance adjustment by the impedance adjuster 16 is performed, and the high-frequency power from the high-frequency power source 12 may be transmitted only slightly. However, if impedance adjustment is not performed, there is a concern about increase in power consumption and reflected power.

  On the other hand, according to this embodiment, even if the impedance fluctuates due to the fluctuation of the distance between the coils 13a and 23a, the impedance from the input terminal 24a of the rectifier 24 to the vehicle battery 22 is included. Accurate impedance can be measured. As a result, impedance adjustment can be suitably performed in a configuration in which power is transmitted in a non-contact manner using the coils 13a and 23a.

  (2) A fixed resistor 25 is provided between the rectifier 24 and the vehicle battery 22, and a changeover switch 26 that switches the connection destination of the rectifier 24 between the fixed resistor 25 and the vehicle battery 22 is provided. The resistance value of the fixed resistor 25 is set to be the same as the impedance of the vehicle battery 22 when the charging DC power is input to the vehicle battery 22, and the high frequency power for impedance adjustment is output from the high frequency power source 12. In this case, the changeover switch 26 is controlled so that the rectifier 24 and the fixed resistor 25 are connected. Thereby, in the situation where the high frequency power for impedance adjustment is output, the situation where the DC power for charging is inputted to the vehicle battery 22 can be virtually created. Therefore, it is possible to improve the accuracy of impedance adjustment using high-frequency power for impedance adjustment.

  Specifically, the vehicle battery 22 appears to have different impedances depending on the input DC power. For this reason, if the power value of the DC power input when performing impedance adjustment differs from the power value of the DC power input when actually charging, the impedance adjustment is performed with high-frequency power for impedance adjustment. Even so, the impedance cannot be adjusted during charging.

  On the other hand, according to the present embodiment, in a situation where high-frequency power for impedance adjustment is output, a situation is created in which the vehicle battery 22 is virtually charged with DC power for charging. Can do. Thereby, the impedance adjustment at the time of charge can be performed using the high frequency electric power for impedance adjustment, and the said inconvenience can be avoided.

  (3) A switching element 34 is provided that operates so that a DC bias voltage is applied when impedance adjustment is performed and no DC bias voltage is applied when impedance adjustment is not performed. Thus, wasteful power consumption of the DC bias power supply 33 can be suppressed by applying the DC bias voltage only when necessary. Moreover, it can suppress that the electric power value of the direct-current power input into the vehicle battery 22 resulting from applying a DC bias voltage deviates from a desired value.

  Specifically, when the impedance adjustment is started and completed, the power supply side controller 14 transmits information indicating the fact to the vehicle side controller 27, and the vehicle side controller 27 switches the switching element based on the information. 34 is configured to perform on / off control. Thereby, the timing which outputs the high frequency electric power for impedance adjustment in the high frequency power supply 12 and the timing which applies DC bias voltage can be synchronized, using the existing structure.

  (4) The vehicle-side device 21 is mounted on the vehicle, and the vehicle battery 22 provided in the vehicle-side device 21 is charged using the DC power rectified by the rectifier 24. Here, the vehicle battery 22 is required to have a larger storage capacity than a battery such as a mobile phone. For this reason, the power value of the power handled by the non-contact power transmission device 10 is very large as compared with that for charging a battery such as the mobile phone. For this reason, power loss and heat generation due to low accuracy of impedance adjustment cannot be ignored, and power consumption and reflected power when impedance adjustment is performed cannot be ignored.

  On the other hand, according to the present embodiment, by applying a DC bias voltage, impedance adjustment can be performed with high-frequency power for impedance adjustment that is smaller than the power value of high-frequency power for charging. it can. Thereby, the non-negligible power loss and the like can be suppressed in the non-contact power transmission apparatus 10 that handles relatively large power. Thereby, the non-contact electric power transmission apparatus 10 suitable for the vehicle which can handle high electric power suitably can be provided.

In addition, you may change the said embodiment as follows.
In embodiment, although the impedance measuring device 15 and the impedance regulator 16 were provided in the ground side apparatus 11, it is not restricted to this, You may provide in the vehicle side apparatus 21. FIG. In this case, for example, the impedance measuring device 15 measures the impedance from the output end of the power receiver 23 (the input end of the rectifier 24) to the vehicle battery 22, and the impedance adjuster 16 adjusts the impedance based on the measurement result. It is good also as a structure. When the impedance adjuster 16 is provided in the vehicle side device 21, the vehicle side controller 27 is configured to control the impedance adjuster 16. Moreover, you may provide the impedance adjuster 16 in both the ground side apparatus 11 and the vehicle side apparatus 21. FIG. The point is that the impedance adjuster 16 may be provided in at least one of the ground side device 11 and the vehicle side device 21, and the position and number of the impedance adjusters 16 are arbitrary.

In addition, instead of the configuration that directly measures the impedance, the reflected power from the power transmitter 13 may be measured, and the impedance may be adjusted based on the reflected power.
Furthermore, although the power supply side controller 14 was used as what controls the impedance regulator 16, it is not restricted to this, You may provide a control circuit separately. In this case, the control circuit, the impedance measuring device 15 and the impedance adjuster 16 may be integrated into one unit.

The DC bias voltage may be equal to or higher than the forward threshold voltage of the positive diode 31a.
The DC bias voltage for operating the positive diode 31a is applied. However, the present invention is not limited to this, and a DC bias voltage for operating the negative diode 31b may be applied. Further, a positive DC bias voltage and a negative DC bias voltage may be alternately applied. In short, a DC bias voltage may be applied so that at least one of the diodes 31a and 31b constituting the diode bridge 31 operates.

  In the embodiment, the DC bias power source 33, the switching element 34, and the inductor 35 are provided to apply the DC bias voltage. However, the present invention is not limited to this. In short, as long as a DC bias voltage can be applied, the specific configuration is arbitrary.

  The rectifier 24 includes the diode bridge 31 that performs full-wave rectification using the plurality of diodes 31a and 31b. Alternatively, the rectifier 24 may be configured to perform half-wave rectification using one diode. In this case, a DC bias voltage equal to or higher than the threshold voltage of the one diode is applied. In short, the number of semiconductor elements used in the rectifier 24 is arbitrary, and the number of semiconductor elements to which the DC bias voltage is applied is arbitrary as long as the rectifier 24 can virtually operate. .

  The semiconductor elements that constitute the rectifier 24 are not limited to the diodes 31a and 31b, and other semiconductor elements such as transistors may be used. In short, the rectifier 24 may be configured to rectify using a semiconductor element that operates when a voltage equal to or higher than the threshold voltage is applied.

  ○ If the power value of the high-frequency power output from the power receiver 23 is measured and the power value of the high-frequency power is less than the operable power value of the rectifier 24 (more specifically, the measured AC voltage amplitude is on the positive side) If it is less than the threshold voltage of the diode 31a), the switching element 34 may be turned on. In this case, impedance adjustment can be performed while using the high-frequency power output from the power receiver 23 as a reference for applying the DC bias voltage.

  The power transmitter 13 may be separately provided with a primary coupling coil that is coupled with a resonance circuit including the primary coil 13a and the primary capacitor 13b by electromagnetic induction. In this case, the primary side coupling coil and the high frequency power source 12 are connected, and the resonance circuit is configured to receive high frequency power from the primary side coupling coil by electromagnetic induction. Similarly, the power receiver 23 is provided with a secondary side coupling coil that is coupled by electromagnetic induction to a resonance circuit including the secondary side coil 23a and the secondary side capacitor 23b, and the resonance of the power receiver 23 is performed using the secondary side coupling coil. Power may be extracted from the circuit.

O The waveform of the AC voltage output from the high-frequency power source 12 is arbitrary, such as a pulse waveform or a sine wave.
O Although the high frequency power supply 12 which outputs high frequency electric power was provided, it is not restricted to this. In short, any AC power source that outputs AC power of a predetermined frequency (for example, 10 kHz to 10 MHz) may be used, and the frequency of the output AC power may be appropriately set in relation to the resonance frequency or the like.

In the embodiment, the capacitors 13b and 23b are provided, but these may be omitted. In this case, magnetic field resonance is performed using the parasitic capacitances of the coils 13a and 23a.
In the embodiment, magnetic field resonance is used in order to realize non-contact power transmission. However, the present invention is not limited to this, and electromagnetic induction may be used.

  In embodiment, although the ground side apparatus 11 was set as the structure provided on the ground, it is not restricted to this, What is necessary is just to be provided in the position which can charge a vehicle. For example, when a garage is provided in the parking space, the configuration may be provided on the wall of the garage.

  In the embodiment, the charging target is the vehicle battery 22 provided in the vehicle, but is not limited thereto, and may be, for example, a mobile phone battery. However, if it pays attention to the point which can charge suitably using the high frequency electric power with a big electric power value, it is more preferable that the charge object is the vehicle battery 22. FIG.

  In the embodiment, the DC power rectified by the rectifier 24 is used to charge the vehicle battery 22, but is not limited to this, for example, drives other electronic devices provided in the vehicle. It may be used for In this case, the other electronic device may have an impedance that varies according to the power value of the input power, or has the same impedance regardless of the power value of the input power. Also good.

  In the embodiment, the resistance value of the fixed resistor 25 is the same as the impedance of the vehicle battery 22 when the charging DC power obtained by rectifying the charging high-frequency power is input to the vehicle battery 22. It was set, but it is not limited to this. For example, it may be a value close to the impedance, and need not be set exactly the same.

The high frequency power supply 12 may be a voltage source having a predetermined internal resistance, a voltage source (switching power supply) capable of ignoring the internal resistance, or a current source.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

(B) The power transmitting device and the power receiving device are configured to exchange information,
The power transmission device includes means for transmitting the first information to the power receiving device when starting the impedance adjustment, and transmitting the second information to the power receiving device when the impedance adjustment is completed,
The power receiving device starts the application of the bias voltage when receiving the first information, and controls the bias switching means to stop the application of the bias voltage when receiving the second information The non-contact power transmission device according to claim 3, comprising:

  (B) When performing the impedance adjustment, the AC power source outputs AC power for impedance adjustment having a power value smaller than the power value of AC power output when charging the vehicle battery. The non-contact power transmission device according to claim 4.

(C) The rectifying unit is the semiconductor element,
A positive semiconductor element used to rectify the positive component of the AC power received by the secondary coil;
A negative semiconductor element used to rectify the negative component of the AC power received by the secondary coil;
With
The bias voltage applying means applies a bias voltage equal to or higher than a threshold voltage of the semiconductor element to either the positive-side semiconductor element or the negative-side semiconductor element. The non-contact power transmission device according to any one of Items 1 to 4 and technical ideas (a) and (b).

(D) an AC power source that outputs AC power, and a power transmission device having a primary coil to which the AC power is input from the AC power source;
A secondary coil that can receive the AC power in a non-contact manner from the primary coil, and a power receiving device having a variable load with different impedance depending on the power value of the input power;
In a non-contact power transmission device comprising:
At least one of the power transmission device and the power receiving device is provided with impedance adjustment means for adjusting impedance,
The AC power supply is configured to be capable of outputting the first AC power and the second AC power having a power value larger than that of the first AC power, and outputs the first AC power when performing at least the impedance adjustment. Is what
A fixed load having an impedance corresponding to an impedance when power when the second AC power is output from the AC power source is input to the variable load;
Connection switching means for switching an input destination of DC power generated by rectifying AC power received by the secondary coil between the variable load and the fixed load;
When performing the impedance adjustment, control means for controlling the connection switching means so that the input destination is the fixed load;
A non-contact power transmission device comprising:

(E) the variable load is a battery;
The second AC power is used when charging the battery,
The control means controls the connection switching means so that the input destination is the fixed load when the impedance adjustment is performed, and the input destination is a battery when the battery is charged. The non-contact power transmission device described in the technical concept (d).

(F) a secondary side coil capable of receiving the AC power in a non-contact manner from a power transmission device having a primary side coil to which AC power is input and an impedance adjustment means for performing impedance adjustment;
A rectifying unit having a semiconductor element that operates when a voltage equal to or higher than a predetermined threshold voltage is applied, and rectifying AC power received by the secondary coil using the semiconductor element into DC power; ,
A load to which the DC power rectified by the rectification unit can be input;
Bias voltage applying means for applying a bias voltage equal to or higher than the threshold voltage to the semiconductor element when at least the impedance adjustment is performed;
A power receiving device comprising:

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Ground side apparatus, 12 ... High frequency power supply, 13 ... Power transmitter, 13a ... Primary side coil, 14 ... Power source side controller, 15 ... Impedance measuring device, 16 ... Impedance adjuster, 21 DESCRIPTION OF SYMBOLS ... Vehicle side equipment, 22 ... Vehicle battery, 23 ... Power receiver, 23a ... Secondary coil, 24 ... Rectifier, 25 ... Fixed resistor, 26 ... Changeover switch, 27 ... Vehicle side controller, 31 ... Diode bridge, 33 ... DC bias power supply 34... Switching element.

Claims (5)

An AC power source that outputs AC power, and a power transmission device having a primary coil to which the AC power is input from the AC power source;
A power receiving device having a secondary coil and a load capable of receiving the AC power in a non-contact manner from the primary coil;
In a non-contact power transmission device comprising:
A rectifying unit that has a semiconductor element that operates when a voltage equal to or higher than a predetermined threshold voltage is applied, and rectifies AC power received by the secondary coil using the semiconductor element into DC power. Prepared,
The DC power can be input to the load;
Impedance adjusting means that is provided in at least one of the power transmitting device and the power receiving device and performs impedance adjustment;
A bias voltage applying unit that is provided in the power receiving device and applies a bias voltage equal to or higher than the threshold voltage to the semiconductor element when at least the impedance adjustment is performed;
A non-contact power transmission device comprising: The AC power supply is configured to be capable of outputting the first AC power and the second AC power having a power value larger than that of the first AC power, and outputs the first AC power when performing at least the impedance adjustment. Is what
The load is a variable load having different impedance depending on the power value of the input DC power,
A fixed load provided between the rectifying unit and the variable load and having an impedance corresponding to an impedance when DC power when the second AC power is output from the AC power source is input to the variable load When,
Connection switching means for switching the connection destination of the rectifying unit between the variable load and the fixed load;
When performing the impedance adjustment, control means for controlling the connection switching means so that the connection destination of the rectification unit is the fixed load;
The non-contact power transmission device according to claim 1, comprising:   The power receiving device includes bias switching means that operates so as to apply the bias voltage to the semiconductor element when the impedance adjustment is performed and not apply the bias voltage to the semiconductor element when the impedance adjustment is not performed. The contactless power transmission device according to claim 1 or 2, wherein the contactless power transmission device is provided. The power receiving device is mounted on a vehicle,
The contactless power transmission apparatus according to claim 1, wherein the load is a vehicle battery. A secondary coil capable of receiving the AC power in a contactless manner from a power transmission device having a primary coil to which AC power is input;
A rectifying unit having a semiconductor element that operates when a voltage equal to or higher than a predetermined threshold voltage is applied, and rectifying AC power received by the secondary coil using the semiconductor element into DC power; ,
A load to which the DC power rectified by the rectification unit can be input;
Impedance adjusting means for performing impedance adjustment;
Bias voltage applying means for applying a bias voltage equal to or higher than the threshold voltage to the semiconductor element when performing at least the impedance adjustment;
A power receiving device comprising: