JP2016220316A - Non-contact power transmission device and power receiving equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission device capable of appropriately detecting an abnormality in a frequency of AC power that is transmitted from power transmitting equipment to power receiving equipment in a non-contact state, and the power receiving equipment.SOLUTION: Power transmitting equipment 11 comprises an AC power source 12 capable of outputting AC power using a power transmission side clock signal CK1, and a power transmitter 13 to which AC power is inputted. Power receiving equipment 21 comprises a power receiver 23 capable of receiving AC power that is inputted to the power transmitter 13, in a non-contact state and a rectifier 24 to which AC power that is received by the power receiver 23 is inputted. The power receiving equipment 21 comprises a microcomputer 26 for power reception side control including a power reception side clock circuit 27 that outputs a power reception side clock signal CK2, and a power reception side frequency detection part 42 for detecting a frequency of AC power from the power receiver 23 to the rectifier 24 using the power reception side clock signal CK2.SELECTED DRAWING: Figure 1

Description

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

  As a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, an AC power source capable of outputting AC power and a power transmission device having a primary coil to which the AC power is input are contactless from the primary coil And a power receiving device having a secondary side coil capable of receiving AC power (see, for example, Patent Document 1). In such a non-contact power transmission device, for example, as shown in Patent Document 1, AC power is transmitted from a power transmitting device to a power receiving device in a non-contact manner by causing magnetic resonance between the primary coil and the secondary coil. .

  Further, in Patent Document 1, a non-contact power transmission device is provided in a power transmission device and detects a frequency of AC power output from an AC power source, and a detection result of the power transmission side frequency detection unit. And an abnormality determination unit that determines whether or not an abnormality has occurred based on the above.

JP 2014-121171 A

  Here, for example, the AC power supply may be configured to output AC power using a power transmission side clock signal output from a power transmission side clock circuit provided in a power transmission device. The power transmission side frequency detection unit may use the power transmission side clock signal to detect the frequency. As described above, in a situation where the power transmission side clock signal is used for both the output of AC power and the frequency detection, if an abnormality occurs in the power transmission side clock circuit and an abnormality occurs in the power transmission side clock signal, power is received from the power transmission device. An abnormality may occur in the frequency of the AC power transmitted in a non-contact manner toward the device, and an abnormality may also occur in the detection result of the power transmission side frequency detection unit. In this case, although the frequency of the transmitted AC power is abnormal, there may be a problem that it is erroneously determined to be normal.

From the above, there is still room for improvement in the configuration for detecting an abnormality in the frequency of transmitted AC power.
The present invention has been made in view of the above-described circumstances, and an object thereof is a non-contact power transmission device capable of preferably detecting an abnormality in the frequency of AC power transmitted in a non-contact manner from a power transmission device to a power reception device, and It is to provide power receiving equipment.

  The non-contact power transmission device that achieves the above object includes an AC power source capable of outputting AC power, a power transmission device having a primary side coil to which the AC power is input, and the input to the primary side coil. A secondary side coil capable of receiving AC power in a contactless manner, and a power receiving device having a load to which the AC power received by the secondary side coil is input. The AC power source can output the AC power using the power transmission side clock signal, and the power receiving device has a power reception side clock circuit that outputs a power reception side clock signal. A power-receiving-side control microcomputer, and using the power-receiving-side clock signal, a power-receiving-side frequency detection unit that detects a frequency of AC power from the secondary coil toward the load, and Contact power transmission apparatus, based on the power receiving side frequency detector of the detection result, characterized in that it comprises an abnormality determining section for determining the occurrence of abnormality.

  According to this configuration, the frequency of the AC power directed from the secondary coil to the load is detected using a power receiving clock signal that is different from the power transmitting clock signal used to output AC power. Thereby, even if it is a case where abnormality arises in the power transmission side clock signal, the frequency of alternating current power can be detected correctly. Then, by determining whether or not an abnormality has occurred based on the detection result, it is possible to detect an abnormality in the frequency of the AC power caused by the abnormality in the power transmission clock signal. Therefore, it is possible to suitably detect an abnormality in the frequency of AC power transmitted in a non-contact manner from the power transmission device to the power reception device.

  In particular, the power reception side frequency detection unit detects the frequency using the power reception side clock signal of the power reception side clock circuit in the power reception side control microcomputer. As a result, there is no need to provide a dedicated clock circuit for detecting the frequency, so that the above-described effects can be obtained while suppressing the complexity of the configuration.

  About the said non-contact electric power transmission apparatus, the said power transmission apparatus is equipped with the power transmission side frequency detection part which detects the frequency of the alternating current power which goes to the said primary side coil from the said AC power supply using the said power transmission side clock signal, The said abnormality The determination unit may determine whether or not an abnormality has occurred based on a power transmission side detection frequency that is a detection result of the power transmission side frequency detection unit and a power reception side detection frequency that is a detection result of the power reception side frequency detection unit.

  According to such a configuration, the abnormality determination unit temporarily determines whether or not an abnormality has occurred based on both the power transmission side detection frequency and the power reception side detection frequency, so that the power reception side clock signal and the power reception side frequency detection unit temporarily Even if an abnormality occurs, it can be determined that there is an abnormality. Therefore, it is possible to cope with an abnormality in the power receiving side clock signal and the power receiving side frequency detection unit.

  About the said non-contact electric power transmission apparatus, the said abnormality determination part has generate | occur | produced abnormality based on the difference of the said power transmission side detection frequency and the said power receiving side detection frequency becoming more than a predetermined threshold value difference. It is good to judge.

According to such a configuration, an abnormality can be suitably detected with a relatively simple configuration of comparing the power transmission side detection frequency and the power reception side detection frequency.
For the non-contact power transmission device, the abnormality determination unit detects an abnormality based on a deviation of the power transmission side detection frequency or the power reception side detection frequency by a predetermined threshold difference with respect to a predetermined setting frequency. It is good to determine that has occurred.

  According to such a configuration, it is possible to suitably detect the abnormality by determining whether or not an abnormality has occurred by comparing the power transmission side detection frequency and the power reception side detection frequency with the set frequency. In particular, according to the present configuration, it is possible to narrow down abnormal factors by combining the comparison result between the power transmission side detection frequency and the set frequency and the comparison result between the power reception side detection frequency and the set frequency.

  About the said non-contact electric power transmission apparatus, when it determines with the abnormality determination part having generate | occur | produced, it is good to provide the stop control part which stops the output of the said alternating current power from the said alternating current power supply.

According to such a configuration, it is possible to suppress non-contact power transmission from being continued in a state where an abnormality has occurred.
A power receiving device that achieves the above object includes a power transmission side clock circuit that outputs a power transmission side clock signal, an AC power source that can output AC power using the power transmission side clock signal, and a primary side to which the AC power is input. A secondary coil capable of receiving the AC power in a contactless manner from a power transmission device having a coil and capable of receiving the AC power input to the primary coil in a contactless manner; and the secondary coil A load to which AC power received by the power supply is input; a power receiving side control microcomputer having a power receiving side clock circuit that outputs a power receiving side clock signal; and the load from the secondary side coil using the power receiving side clock signal. A power-receiving-side frequency detection unit that detects the frequency of the alternating-current power toward the power source, and whether or not an abnormality has occurred is determined based on a detection result of the power-receiving-side frequency detection unit. .

  According to this configuration, the frequency of the AC power directed from the secondary coil to the load is detected using a power receiving clock signal that is different from the power transmitting clock signal used to output AC power. Thereby, even if it is a case where abnormality arises in the power transmission side clock signal, the frequency of alternating current power can be detected correctly. Then, by determining whether or not an abnormality has occurred based on the detection result, it is possible to detect an abnormality in the frequency of the AC power caused by the abnormality in the power transmission side clock signal. Therefore, it is possible to suitably detect an abnormality in the frequency of AC power transmitted in a non-contact manner from the power transmission device to the power reception device.

  According to this invention, it is possible to suitably detect an abnormality in the frequency of AC power transmitted in a non-contact manner from a power transmitting device to a power receiving device.

The circuit diagram which shows the electrical structure of power transmission equipment and a non-contact power transmission apparatus. The flowchart which shows an abnormality determination process. The flowchart which shows a frequency change process.

Hereinafter, an embodiment of a power transmission device (power transmission device) and a non-contact power transmission device (non-contact power transmission system) will be described below.
As shown in FIG. 1, the non-contact power transmission apparatus 10 includes a power transmission device 11 and a power reception device 21 that can transmit power in a non-contact manner. The power transmission device 11 is provided on the ground, and the power receiving device 21 is mounted on the vehicle. The power transmission device 11 can be said to be a ground side device or a primary side device. The power receiving device 21 can be said to be a vehicle side device or a secondary side device.

  The power transmission device 11 includes an AC power supply 12 that can output AC power. The AC power source 12 includes, for example, an AC / DC converter 12a that converts system power as external power supplied from a system power source E as external power into DC power, and DC / AC conversion that converts the DC power into AC power. And a container 12b. The DC / AC converter 12b has a switching element Q1, and outputs alternating-current power having a frequency corresponding to the switching frequency when the switching element Q1 is periodically turned ON / OFF (switching operation). That is, the frequency of the AC power output from the AC power supply 12 corresponds to (matches) the switching frequency of the switching element Q1. The specific configuration of the DC / AC converter 12b is arbitrary, but for example, a class D amplifier or the like can be considered.

  The AC power output from the AC power supply 12 is transmitted to the power receiving device 21 in a non-contact manner, and used for charging the vehicle battery 22 as a power storage device provided in the power receiving device 21. Specifically, the non-contact power transmission apparatus 10 includes a power transmitter 13 provided in the power transmission device 11 for performing power transmission between the power transmission device 11 and the power reception device 21, and a power receiver 23 provided in the power reception device 21. It has. The power transmission device 11 is configured such that AC power output from the AC power source 12 is input to the power transmitter 13.

  The power transmitter 13 and the power receiver 23 have the same configuration, and both are configured to be capable of magnetic field resonance. Specifically, the power transmitter 13 has a resonance circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The power receiver 23 has a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel. The resonant frequencies of both resonant circuits are set to be the same.

  According to such a configuration, in a situation where the relative positions of the power transmitter 13 (specifically, the primary side coil 13a) and the power receiver 23 (specifically, the secondary side coil 23a) are at positions where magnetic field resonance is possible, AC power is not generated. When input to the power transmitter 13, the power transmitter 13 and the power receiver 23 perform magnetic field resonance. As a result, the power receiver 23 receives part of the energy from the power transmitter 13. That is, the power receiver 23 receives AC power from the power transmitter 13.

  The power receiving device 21 has a vehicle battery 22, a rectifier 24 that rectifies the AC power received by the power receiver 23 into DC power, and a rectifier 24 that rectifies the AC power received by the power receiver 23 as a load to which the AC power received by the power receiver 23 is input. And a DC / DC converter 25 that performs voltage value conversion of the direct current power. The DC / DC converter 25 has a switching element, for example, and performs voltage value conversion when the switching element is periodically turned ON / OFF. The vehicle battery 22 is charged by receiving direct-current power output from the DC / DC converter 25.

  As illustrated in FIG. 1, the power transmission device 11 includes a power transmission side control microcomputer (power transmission side control unit) 14 that controls the AC power supply 12. The power transmission side control microcomputer 14 includes a power transmission side clock circuit 15 that outputs a power transmission side clock signal CK1. The power transmission side clock circuit 15 includes a crystal resonator 15a and a frequency dividing circuit 15b, and outputs a power transmission side clock signal CK1 having a predetermined frequency using the crystal resonator 15a and the frequency dividing circuit 15b. The power transmission side clock circuit 15 outputs the power transmission side clock signal CK1 to the DC / AC converter 12b.

  The power transmission side control microcomputer 14 outputs the first power supply control signal SG1 to the AC / DC converter 12a, and outputs the second power supply control signal SG2 to the DC / AC converter 12b, whereby the AC / DC converter 12a. And controls the DC / AC converter 12b.

  When the first power supply control signal SG1 corresponding to the ON operation is input, the AC / DC converter 12a converts the system power to DC power and outputs the first power control signal corresponding to the OFF operation. When SG1 is input, power conversion is not performed.

  When the second power supply control signal SG2 corresponding to the ON operation is input to the DC / AC converter 12b and the power transmission side clock signal CK1 is input, the DC / AC converter 12b converts the direct current power into alternating current using the power transmission side clock signal CK1. Convert to electricity. Specifically, the DC / AC converter 12b generates a pulse signal having a predetermined frequency using the power transmission side clock signal CK1, and periodically turns the switching element Q1 on and off using the pulse signal. Converts DC power to AC power. That is, the AC power supply 12 outputs AC power using the power transmission side clock signal CK1. On the other hand, the DC / AC converter 12b does not perform power conversion when the second power control signal SG2 corresponding to the OFF operation is input.

  From the above, the power transmission side control microcomputer 14 can perform ON / OFF control of AC power from the AC power supply 12 by controlling the power supply control signals SG1 and SG2 output to the converters 12a and 12b. .

  Further, when outputting the second power control signal SG2 corresponding to the ON operation, the power transmission side control microcomputer 14 outputs an instruction signal related to the frequency of the pulse signal to the DC / AC converter 12b. When the instruction signal is input, the DC / AC converter 12b generates a pulse signal having a frequency indicated by the instruction signal, and periodically turns on / off the switching element Q1 using the pulse signal. . Thereby, AC power having a frequency corresponding to the instruction signal is output from the DC / AC converter 12b. That is, the power transmission side control microcomputer 14 is configured to be able to change the frequency of the AC power output from the AC power supply 12.

  In the following description, the frequency of AC power set by the power transmission side control microcomputer 14 is referred to as a set frequency ft. The set frequency ft is the frequency of the pulse signal set in the instruction signal. The set frequency ft can also be said to be a target frequency.

  Incidentally, the set frequency ft is arbitrary as long as it is a predetermined value, but corresponds to the resonance frequency of the power transmitter 13 and the power receiver 23 so that power can be transmitted between the power transmitter 13 and the power receiver 23. It is good to set it. For example, the initial set frequency ft0, which is the initial value of the set frequency ft, is set to be the same as the resonance frequency of the power transmitter 13 and the power receiver 23.

  When the frequency of the power transmission side clock signal CK1 is different from the set frequency ft, the DC / AC converter 12b generates a pulse signal of the set frequency ft by multiplying or dividing the power transmission side clock signal CK1. To do.

  As shown in FIG. 1, the power receiving device 21 includes a power receiving side control microcomputer (power receiving side control unit) 26 that performs various controls of the power receiving device 21 such as the DC / DC converter 25. The power receiving side control microcomputer 26 includes a power receiving side clock circuit 27 that outputs a power receiving side clock signal CK2. The power receiving side clock circuit 27 includes a crystal resonator 27a and a frequency dividing circuit 27b, and outputs a power receiving side clock signal CK2 having a predetermined frequency using the crystal resonator 27a and the frequency dividing circuit 27b.

  The power receiving side control microcomputer 26 generates a pulse signal having a predetermined duty ratio by using the power receiving side clock signal CK2, and periodically turns ON / OFF the switching element of the DC / DC converter 25 by the pulse signal.

  Here, the input impedance of the DC / DC converter 25 (in other words, the impedance from the input terminal of the DC / DC converter 25 to the vehicle battery 22) is set to the ON / OFF duty ratio of the switching element of the DC / DC converter 25. Dependent.

  Further, the impedance ZL of the vehicle battery 22 varies depending on the power value of the input DC power. Correspondingly, the power-receiving-side control microcomputer 26, for example, approaches the input impedance of the DC / DC converter 25 to a predetermined specified impedance (preferably matches) regardless of the fluctuation of the impedance ZL of the vehicle battery 22. As described above, the duty ratio of the pulse signal for controlling the switching element of the DC / DC converter 25 is variably controlled. For this reason, the input impedance of the rectifier 24 approaches a constant value (hereinafter referred to as a target load impedance) regardless of fluctuations in the impedance ZL of the vehicle battery 22. In the present embodiment, the range from the rectifier 24 to the vehicle battery 22 corresponds to the “load”.

  The power receiving device 21 includes a voltage sensor 28 that detects an input voltage value of the vehicle battery 22. The voltage sensor 28 transmits the detection result to the power receiving side control microcomputer 26. Thereby, the power receiving side control microcomputer 26 can grasp the input voltage value of the vehicle battery 22. The power receiving side control microcomputer 26 determines whether or not an abnormality has occurred in the charging of the vehicle battery 22 by determining whether or not the input voltage value is a predetermined normal value. The power receiving side control microcomputer 26 grasps the state of charge of the vehicle battery 22 based on various parameters including the input voltage value.

  The power transmission side control microcomputer 14 and the power reception side control microcomputer 26 can wirelessly communicate with each other and can exchange information with each other. Although the communication method is arbitrary, for example, Bluetooth (registered trademark), Zigbee (registered trademark), Wi-fi, and the like are conceivable.

  As shown in FIG. 1, the non-contact power transmission device 10 includes a plurality of impedance converters 31 and 32 provided between the AC power supply 12 and the vehicle battery 22. The primary side impedance converter 31 provided in the power transmission device 11 is provided between the AC power supply 12 and the power transmission device 13, and the secondary side impedance converter 32 provided in the power reception device 21 is a power receiver. 23 and the rectifier 24. Each impedance converter 31 and 32 is comprised by LC circuit which has an inductor and a capacitor, for example.

  The secondary side impedance converter 32 performs impedance conversion so that the impedance from the output end of the power receiver 23 to the vehicle battery 22 approaches (preferably matches) a predetermined secondary side specific impedance. Specifically, the constant (impedance) of the secondary side impedance converter 32 is such that when the input impedance of the rectifier 24 is the target load impedance, the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 is the secondary side. The specific load impedance is set so as to correspond to the target load impedance. Note that the secondary side specific impedance is arbitrary as long as it is a predetermined value. For example, a value with higher transmission efficiency than the case where the secondary side impedance converter 32 is not provided is conceivable.

  The primary side impedance converter 31 impedance-converts the input impedance of the power transmitter 13 so that AC power having a desired power value is output from the AC power supply 12. For example, the impedance from the output terminal of the AC power supply 12 to the vehicle battery 22 is set as a power supply load impedance Zp, and the power supply load impedance Zp at which the AC power supply 12 can output AC power having a desired power value is specified power supply load impedance Zpt. And The specific power supply load impedance Zpt is determined by the required power value and the specifications of the AC power supply 12 (rated voltage value, rated current value, etc.).

  In this case, the primary side impedance converter 31 performs impedance conversion so that the power load impedance Zp approaches (preferably matches) the specific power load impedance Zpt. Specifically, the constant of the primary impedance converter 31 is a reference position in which the relative positions of the coils 13a and 23a are determined in advance, and the impedance from the output end of the power receiver 23 to the vehicle battery 22 is The power supply load impedance Zp is set so as to approach the specific power supply load impedance Zpt in the case of the secondary side specific impedance.

  The reference position is arbitrary as long as both the coils 13a and 23a can be magnetically resonated. For example, the primary coil 13a is installed on the ground, and the secondary coil 23a is installed on the bottom of the vehicle. In the configuration, the two coils 13a, 23a are positions facing each other in the vehicle height direction.

  Here, the non-contact power transmission apparatus 10 of the present embodiment includes a configuration for detecting an abnormality in the frequency of the AC power transmitted from the power transmission device 11 to the power reception device 21. The configuration will be described below.

  As shown in FIG. 1, the power transmission device 11 includes a power transmission side frequency detection unit 41 that detects the frequency of AC power from the AC power source 12 toward the power transmitter 13. The power transmission side frequency detection unit 41 receives the power transmission side clock signal CK1 from the power transmission side clock circuit 15. The power transmission side frequency detection unit 41 detects the frequency of the AC power output from the AC power supply 12 using the power transmission side clock signal CK1.

  Specifically, the power transmission side frequency detection unit 41 measures a predetermined period that is determined in advance using the power transmission side clock signal CK1, and counts specific points of the output voltage waveform within the predetermined period. And the power transmission side frequency detection part 41 derives | leads-out the frequency of alternating current power from the count number of the specific point in a regulation period. The specific point is, for example, a zero cross point, a rising point, or a falling point.

  And the power transmission side frequency detection part 41 transmits the power transmission side detection frequency f1 which is the detection result to the microcomputer 14 for power transmission side control. Thereby, the power transmission side control microcomputer 14 can grasp the power transmission side detection frequency f1.

  Similarly, the power receiving device 21 includes a power receiving side frequency detection unit 42 that detects the frequency of AC power from the secondary coil 23a toward the load. The power receiving side frequency detection unit 42 receives the power receiving side clock signal CK <b> 2 from the power receiving side clock circuit 27. The power reception side frequency detection unit 42 detects the frequency of the AC power from the power receiver 23 toward the rectifier 24 using the power reception side clock signal CK2. Then, the power reception side frequency detection unit 42 transmits the power reception side detection frequency f2 as the detection result to the power reception side control microcomputer 26. The specific mode of frequency detection is the same as that of the power transmission side frequency detection unit 41 except that the power reception side clock signal CK2 is used instead of the power transmission side clock signal CK1, and thus detailed description thereof is omitted.

  When a predetermined power transmission start condition is satisfied in a situation where both coils 13a and 23a are arranged at positions where magnetic resonance can be achieved, the power transmission-side control microcomputer 14 converts the AC power with the initial setting frequency ft0 into the AC power supply. The AC power supply 12 is controlled so as to be output from the power supply 12. As a result, AC power is transmitted (transmitted) from the power transmitting device 11 (power transmitter 13) to the power receiving device 21 (power receiver 23).

  The power transmission-side control microcomputer 14 is in a state where contactless power transmission from the power transmission device 11 to the power receiving device 21 is performed, that is, whether there is an abnormality in the frequency of AC power during AC power transmission. The abnormality determination process for determining whether or not is executed periodically. The abnormality determination process will be described in detail below. In the present embodiment, the power transmission-side control microcomputer 14 that executes the abnormality determination process corresponds to an “abnormality determination unit” and a “stop control unit”.

As shown in FIG. 2, the power transmission side control microcomputer 14 first grasps the power transmission side detection frequency f1 in step S101.
Then, in step S102, the power transmission side control microcomputer 14 grasps the power reception side detection frequency f2. Specifically, the power transmission side control microcomputer 14 transmits a request signal of the power reception side detection frequency f <b> 2 to the power reception side control microcomputer 26. Based on the reception of the request signal, the power receiving side control microcomputer 26 grasps the power receiving side detection frequency f2, and transmits information regarding the grasped power receiving side detection frequency f2 to the power transmission side control microcomputer 14. The power transmission side control microcomputer 14 grasps the power reception side detection frequency f2 by receiving information on the power reception side detection frequency f2.

  In subsequent step S103, the power transmission side control microcomputer 14 determines whether or not the difference (deviation amount) between the power transmission side detection frequency f1 and the power reception side detection frequency f2 is equal to or greater than a predetermined threshold difference δfth. Specifically, the power transmission side control microcomputer 14 calculates the absolute value of the difference between the power transmission side detection frequency f1 and the power reception side detection frequency f2, and determines whether or not the absolute value is greater than or equal to the threshold difference δfth.

  If the calculated absolute value is greater than or equal to the threshold difference δfth, the power transmission side control microcomputer 14 executes the abnormality handling process in step S104 and ends the abnormality determination process. The power transmission-side control microcomputer 14 stops the output of AC power from the AC power supply 12, for example, in the abnormality handling process. Specifically, the power transmission side control microcomputer 14 switches each power supply control signal SG1, SG2 from one corresponding to the ON operation to one corresponding to the OFF operation.

  On the other hand, if the calculated absolute value is less than the threshold difference δfth, the power transmission-side control microcomputer 14 makes a negative determination in step S103, proceeds to step S104, and continues the AC power transmission to determine this abnormality. The process ends.

  Further, the power transmission side control microcomputer 14 executes frequency change processing for changing the set frequency ft based on the fact that a predetermined frequency change condition is satisfied during transmission of AC power. The frequency changing condition is arbitrary. For example, the power load impedance Zp varies as a result of the relative position of the primary side coil 13a and the secondary side coil 23a changing during transmission of AC power. A case where Zp deviates from the specific power load impedance Zpt by a predetermined allowable value or more can be considered.

  When the frequency change condition is set as described above, the power transmission device 11 may include a sensor that detects the output voltage value and the output current value of the AC power supply 12. And the power transmission side control microcomputer 14 is good to grasp | ascertain the power supply load impedance Zp regularly from the detection result of the said sensor during transmission of alternating current power. The allowable value may be set based on the specifications of the AC power supply 12 so that AC power having a required power value can be output, for example.

  The frequency change process will be described below. For convenience of explanation, the frequency of the AC power before the change is assumed to be the initial set frequency ft0. Incidentally, the power transmission side control microcomputer 14 prohibits the execution of the abnormality determination process during the execution of the frequency change process.

  As shown in FIG. 3, the power transmission side control microcomputer 14 first grasps the set frequency ft of the change destination in step S201. The set frequency ft of the change destination is a set frequency ft in which the power load impedance Zp is closer to the specific power load impedance Zpt than the set frequency ft before the change (initial set frequency ft0).

  That is, the power load impedance Zp depends on the frequency of the AC power output from the AC power supply 12. The power transmission side control microcomputer 14 has data relating to the correlation between the power supply load impedance Zp and the set frequency ft. By referring to the data, the power supply is controlled at the current relative position of the coils 13a and 23a. The set frequency ft in which the load impedance Zp approaches the specific power load impedance Zpt is grasped. In other words, the set frequency ft to be changed can be said to be a value that allows the AC power supply 12 to output AC power of a desired power value under the current relative position conditions of the coils 13a and 23a. It can be said that the AC power having a desired power value can be stably output than the set frequency ft.

  In the subsequent step S202, the power transmission side control microcomputer 14 changes the set frequency ft. Specifically, the power transmission-side control microcomputer 14 outputs to the DC / AC converter 12b an instruction signal corresponding to the set frequency ft to be changed to the DC / AC converter 12b. The DC / AC converter 12b generates a pulse signal having the same frequency as the set frequency ft to be changed using the power transmission side clock signal CK1, and periodically turns on / off the switching element Q1 using the pulse signal. Accordingly, if the power transmission device 11 is operating normally, the frequency of the AC power output from the AC power source 12, that is, the frequency of the AC power transmitted from the power transmission device 11 to the power receiving device 21 is the set frequency ft of the change destination. It becomes. The power transmission side control microcomputer 14 that executes the process of step S202 corresponds to the “change unit”.

  Thereafter, the power transmission side control microcomputer 14 confirms whether or not the set frequency ft has been normally changed in steps S203 to S209. In other words, the confirmation can be said to be an abnormality determination as to whether or not an abnormality has occurred in the frequency of the AC power.

Specifically, the power transmission side control microcomputer 14 first grasps the power transmission side detection frequency f1 in step S203.
In subsequent step S204, the power transmission side control microcomputer 14 determines whether or not the power transmission side detection frequency f1 is shifted by a predetermined threshold difference δfth or more with respect to the set frequency ft. Specifically, the power transmission side control microcomputer 14 determines whether or not the absolute value of the difference between the power transmission side detection frequency f1 and the set frequency ft is greater than or equal to the threshold difference δfth.

  Here, when the absolute value of the difference between the power transmission side detection frequency f1 and the set frequency ft is equal to or greater than the threshold difference δfth, an abnormality not caused by the power transmission side clock signal CK1 occurs in the power transmission device 11 (for example, the AC power supply 12). Therefore, there is a high probability that the set frequency ft has not been changed normally. The abnormality includes a poor followability with respect to a change in the set frequency ft in the power transmission device 11.

  In this case, the power transmission side control microcomputer 14 determines that an abnormality not caused by the power transmission side clock signal CK1 has occurred in the power transmission device 11, proceeds to step S205, and executes the first abnormality response process. The frequency change process ends. The power transmission-side control microcomputer 14 stops the output of AC power from, for example, the AC power supply 12 in the first abnormality handling process. Then, the power transmission side control microcomputer 14 informs the power transmission device 11 that an abnormality other than the abnormality of the power transmission side clock signal CK1 has occurred and the set frequency ft has not been normally changed, and the power receiving side. The control microcomputer 26 is notified of the content. The power receiving side control microcomputer 26 executes a process related to stopping charging of the vehicle battery 22 based on the reception of the notification.

  On the other hand, when the absolute value of the difference between the transmission-side detection frequency f1 and the set frequency ft is less than the threshold difference δfth, the AC power frequency has been changed normally, or an abnormality has occurred in the transmission-side clock signal CK1. There is a possibility.

  In this case, the power transmission side control microcomputer 14 makes a negative determination in step S204, proceeds to step S206, and grasps the power reception side detection frequency f2. This process is the same as the process in step S102.

  Then, in step S207, the power transmission side control microcomputer 14 determines whether or not the power reception side detection frequency f2 is deviated by a predetermined threshold difference δfth or more with respect to the set frequency ft. Specifically, the power transmission side control microcomputer 14 determines whether or not the absolute value of the difference between the power reception side detection frequency f2 and the set frequency ft is greater than or equal to the threshold difference δfth.

  When the absolute value of the difference between the power transmission side detection frequency f1 and the set frequency ft is less than the threshold difference δfth and the absolute value of the difference between the power reception side detection frequency f2 and the set frequency ft is greater than or equal to the threshold difference δfth (step S204) : NO, step S207: YES), the probability that an abnormality has occurred in the power transmission side clock signal CK1 or the power receiving device 21 is high. The abnormality of the power receiving device 21 includes poor followability to the change of the set frequency ft in the power receiving device 21.

  In this case, the power transmission-side control microcomputer 14 determines that an abnormality has occurred in the power-transmission-side clock signal CK1 or the power receiving device 21, proceeds to step S208, executes the second abnormality response process, and changes this frequency. The process ends. The power transmission-side control microcomputer 14 stops the output of AC power from, for example, the AC power supply 12 in the second abnormality handling process. Then, the power transmission side control microcomputer 14 notifies that the abnormality has occurred in the power transmission side clock signal CK1 or the power receiving device 21 and the setting frequency ft has not been changed normally, and the power reception side control microcomputer 14 26 is notified of the content.

  On the other hand, if the absolute value of the difference between the power reception side detection frequency f2 and the set frequency ft is less than the threshold difference δfth, the power transmission side control microcomputer 14 determines that the change of the set frequency ft has been performed normally. In this case, the power transmission side control microcomputer 14 makes a negative determination in step S207, proceeds to step S209, continues the transmission of AC power at the set frequency ft, and ends the frequency change process.

  The power transmission side control microcomputer 14 outputs power control signals SG1, SG2 corresponding to the OFF operation to the converters 12a, 12b from the AC power supply 12 when a predetermined termination condition is satisfied. Stop the output of AC power.

Next, the operation of this embodiment will be described.
The determination of whether or not an abnormality in the frequency of the AC power generated using the power transmission side clock signal CK1 has occurred is made based on the power reception side detection frequency f2 detected using the power reception side clock signal CK2. When it is determined that an abnormality has occurred in the frequency of the AC power, the output of the AC power from the AC power supply 12 is stopped.

According to the embodiment described above in detail, the following effects are obtained.
(1) The non-contact power transmission device 10 includes a power transmission device 11 and a power reception device 21 that perform non-contact power transmission. The power transmission device 11 includes a power transmission side clock circuit 15 that outputs a power transmission side clock signal CK1, an AC power source 12 that can output AC power using the power transmission side clock signal CK1, and a power transmitter 13 that receives AC power (details). Is provided with a primary coil 13a). The power receiving device 21 includes a power receiver 23 (specifically, a secondary coil 23a) capable of receiving AC power input to the power transmitter 13 in a contactless manner, and a load to which AC power received by the power receiver 23 is input. As a rectifier 24, a DC / DC converter 25, and a vehicle battery 22. The power receiving device 21 uses the power receiving side clock circuit 27 that outputs the power receiving side clock signal CK2 and the power receiving side clock signal CK2 to the rectifier 24 from the secondary side coil 23a. And a power receiving side frequency detecting unit 42 that detects the frequency of the AC power. Then, the power transmission side control microcomputer 14 of the non-contact power transmission apparatus 10 performs an abnormality determination that determines whether or not an abnormality has occurred based on the detection result of the power reception side frequency detection unit 42.

  According to this configuration, the frequency of the AC power from the secondary coil 23a to the rectifier 24 is detected using the power receiving clock signal CK2 different from the power transmitting clock signal CK1 used to output AC power. The Thus, even if an abnormality occurs in the power transmission side clock signal CK1, the power reception side frequency detection unit 42 can accurately detect the frequency of the transmitted AC power. Then, by performing abnormality determination based on the power reception side detection frequency f2 that is the detection result of the power reception side frequency detection unit 42, it is possible to suitably detect an abnormality in the frequency of the AC power caused by the abnormality of the power transmission side clock signal CK1.

  More specifically, if an abnormality occurs in the frequency dividing circuit 15b of the power transmission side clock circuit 15 and an abnormality occurs in the power transmission side clock signal CK1, the power transmission side clock signal CK1 is used in the DC / AC converter 12b. An abnormality occurs in the frequency of the generated pulse signal. Then, an abnormality occurs in the frequency of the transmitted AC power. Further, when an abnormality occurs in the power transmission side clock signal CK1, the specified period measured by the power transmission side frequency detection unit 41 using the power transmission side clock signal CK1 is shifted. For this reason, the power transmission side detection frequency f1 detected by the power transmission side frequency detection unit 41 is not an accurate value. In this case, if the configuration is such that the abnormality determination of the frequency of the transmitted AC power is performed based on the power transmission side detection frequency f1, the abnormality of the frequency of the AC power due to the abnormality of the power transmission side clock signal CK1 may not be detected. is there.

  On the other hand, in the present embodiment, the power reception side detection frequency f2 used for abnormality determination is a parameter detected using a power reception side clock signal CK2 different from the power transmission side clock signal CK1, and thus the power transmission side clock. Unaffected by abnormality of signal CK1. Thereby, the abnormality of the frequency of alternating current power resulting from abnormality of power transmission side clock signal CK1 is detectable. Therefore, it is possible to suitably detect an abnormality in the frequency of AC power transmitted from the power transmitting device 11 to the power receiving device 21 in a contactless manner.

  (2) In particular, the power receiving side frequency detector 42 detects the frequency using the power receiving side clock signal CK2 of the power receiving side clock circuit 27 in the power receiving side control microcomputer 26. Thereby, since it is not necessary to provide a dedicated clock circuit, the effect (1) can be obtained while suppressing the complexity of the configuration.

  (3) The power transmission device 11 includes a power transmission side frequency detection unit 41 that detects the frequency of AC power from the AC power source 12 toward the power transmitter 13 using the power transmission side clock signal CK1. The power transmission side control microcomputer 14 performs abnormality determination based on the power transmission side detection frequency f1 and the power reception side detection frequency f2 which are detection results of the power transmission side frequency detection unit 41. Accordingly, even if an abnormality occurs in the power receiving side clock signal CK2 or the power receiving side frequency detection unit 42, it can be determined that there is an abnormality. Therefore, it is possible to cope with the abnormality of the power receiving side clock signal CK2 and the power receiving side frequency detection unit 42.

  (4) The power transmission side control microcomputer 14 determines that an abnormality has occurred based on the fact that the difference between the power transmission side detection frequency f1 and the power reception side detection frequency f2 is equal to or greater than a predetermined threshold difference δfth. To do. According to this configuration, it is possible to detect an abnormality or the like in the frequency of the transmitted AC power with a relatively simple configuration of comparing the power transmission side detection frequency f1 and the power reception side detection frequency f2.

  (5) In the frequency change process, the power transmission side control microcomputer 14 is based on the fact that the power transmission side detection frequency f1 or the power reception side detection frequency f2 is shifted by a threshold difference δfth or more with respect to a predetermined set frequency ft. Judge as abnormal. According to such a configuration, it is possible to suitably detect an abnormality in the frequency of the AC power by performing abnormality determination by comparing the power transmission side detection frequency f1 and the power reception side detection frequency f2 with the set frequency ft.

  In particular, according to the present configuration, abnormality factors can be narrowed down by combining the comparison result between the power transmission side detection frequency f1 and the set frequency ft and the comparison result between the power reception side detection frequency f2 and the set frequency ft. it can.

  More specifically, when the power transmission side detection frequency f1 and the set frequency ft are shifted by the threshold difference δfth or more, there is a high probability that the power transmission device 11 has an abnormality other than the power transmission side clock signal CK1. On the other hand, when the difference between the power transmission side detection frequency f1 and the set frequency ft is less than the threshold difference δfth and the power reception side detection frequency f2 and the set frequency ft are shifted by the threshold difference δfth or more, the power transmission side clock signal CK1 or There is a high probability that an abnormality has occurred in the power receiving device 21 (for example, the power receiving side clock signal CK2 or the power receiving side frequency detection unit 42).

  On the other hand, in this embodiment, the power transmission side control microcomputer 14 causes the power transmission device 11 to transmit the power transmission side clock signal CK1 when the power transmission side detection frequency f1 and the set frequency ft are shifted by the threshold difference δfth or more. It is determined that an abnormality other than an abnormality has occurred. In the power transmission side control microcomputer 14, the difference between the power transmission side detection frequency f1 and the set frequency ft is less than the threshold difference δfth, and the power reception side detection frequency f2 and the set frequency ft are shifted by the threshold difference δfth or more. In this case, it is determined that an abnormality has occurred in the power transmission side clock signal CK1 or the power receiving device 21. Thereby, abnormality factors can be narrowed down, and the subsequent response can be suitably performed.

  (6) The power transmission device 11 includes a primary side impedance converter 31 provided between the AC power source 12 and the primary side coil 13a. The constant of the primary side impedance converter 31 is the input impedance of the power transmitter 13 (in other words, the primary side coil 13a) when the relative positions of both the coils 13a and 23a are arranged at a predetermined reference position. It is set correspondingly. Specifically, the constant of the primary impedance converter 31 is such that the power supply load impedance Zp approaches the specific power supply load impedance Zpt when the relative positions of the coils 13a and 23a are arranged at a predetermined reference position. Is set to Thereby, the AC power supply 12 can output AC power having a desired power value.

  Here, if the relative position of both the coils 13a and 23a varies, the power load impedance Zp also varies. And when power supply load impedance Zp shifts more than the predetermined allowable value with respect to specific power supply load impedance Zpt, the situation where the alternating current power of a desired electric power value is not output may arise.

  On the other hand, in this embodiment, the power transmission side control microcomputer 14 changes the set frequency ft when the power load impedance Zp deviates from the specific power load impedance Zpt by a predetermined allowable value or more. Thereby, even if the constant of the primary side impedance converter 31 is fixed, the power supply load impedance Zp can be variably controlled, and the power supply load impedance Zp can be brought close to the specific power supply load impedance Zpt.

  (7) Here, in the configuration in which the set frequency ft is changed in order to bring the power supply load impedance Zp close to the specific power supply load impedance Zpt, followability to the change of the set frequency ft is required. For this reason, there is a case where it is desired to detect an abnormality that the followability to the change of the set frequency ft is poor.

  On the other hand, in this embodiment, the power transmission side control microcomputer 14 executes the process of changing the set frequency ft (step S202), and then transmits the power transmission side detection frequency f1, the power reception side detection frequency f2, and the set frequency ft. Make a comparison. Thereby, it can be determined whether the followability with respect to the change of the setting frequency ft is favorable. In particular, by comparing not only the detection frequencies f1 and f2 but also the detection frequencies f1 and f2 with the set frequency ft, it is possible to directly grasp the followability to the change of the set frequency ft.

  (8) The power transmission side control microcomputer 14 stops the output of the AC power when an abnormality in the frequency of the AC power is detected. Thereby, non-contact electric power transmission in a state with abnormality can be controlled.

In addition, you may change the said embodiment as follows.
In step S104, step S205, and step S208, the power transmission side control microcomputer 14 may execute a process of reducing the power value of the AC power without stopping the output of the AC power.

The power transmission side control microcomputer 14 may periodically grasp the power transmission side detection frequency f1 or the power reception side detection frequency f2 and perform variable control of the set frequency ft based on the grasp result.
The power transmission side control microcomputer 14 is configured to compare both detection frequencies f1 and f2 in the abnormality determination process, but is not limited to this, and compares both detection frequencies f1 and f2 with the set frequency ft. It may be configured. Similarly, the power transmission side control microcomputer 14 may execute steps S101 to S105 in the frequency change process instead of steps S203 to S209.

The power transmission side frequency detection unit 41 may have a dedicated clock circuit and detect the frequency using the clock signal of the clock circuit.
○ The power transmission side frequency detection unit 41 may be omitted. In this case, the power transmission side control microcomputer 14 may perform the abnormality determination by comparing the power reception side detection frequency f2 with the set frequency ft.

A specific mode of abnormality determination is not limited to that of the embodiment, but is arbitrary.
The power transmission-side control microcomputer 14 may execute a process of specifying which of the power transmission device 11 and the power reception device 21 is abnormal in the abnormality handling process in step S104. Specifically, for example, the power transmission side control microcomputer 14 refers to the time variation of the power transmission side detection frequency f1 and the time variation of the power reception side detection frequency f2, and an abnormality has occurred in the device corresponding to the greatly varied one. It may be determined that For example, when the power transmission side detection frequency f1 fluctuates more than the power reception side detection frequency f2, the power transmission side control microcomputer 14 transmits power when the difference between the detection frequencies f1 and f2 is greater than or equal to the threshold difference δfth. It may be determined that an abnormality has occurred in the device 11.

  The power receiving side control microcomputer 26 may execute abnormality determination processing or the like. In this case, the power transmission side control microcomputer 14 may transmit information necessary for the abnormality determination process (for example, the power transmission side detection frequency f1) to the power reception side control microcomputer 26. If the power receiving side control microcomputer 26 determines that an abnormality has occurred, the power receiving side control microcomputer 26 transmits a power transmission stop signal to the power transmission side control microcomputer 14, and the power transmission side control microcomputer 14 receives the power transmission stop signal. Based on this, the output stop process of the AC power supply 12 may be executed.

○ Frequency change processing may be omitted.
The DC / DC converter 25 may be omitted.
The load is not limited to the rectifier 24 and the vehicle battery 22 and is arbitrary.

  ○ The specific configuration of the AC power supply 12 is arbitrary. For example, in a configuration in which DC power is input as external power, the AC power supply may include a DC / DC converter instead of the AC / DC converter 12a.

  The power transmission side control microcomputer 14 may generate a pulse signal corresponding to the set frequency ft using the power transmission side clock signal CK1, and output the generated pulse signal to the DC / AC converter 12b. The DC / AC converter 12b periodically turns on / off the switching element Q1 with the pulse signal. Even in this case, it can be said that the DC / AC converter 12b is converting DC power into AC power using the power transmission side clock signal CK1. Specifically, when the frequency of the power transmission side clock signal CK1 and the set frequency ft are different, the power transmission side control microcomputer 14 multiplies or divides the power transmission side clock signal CK1 to set the frequency ft. The pulse signal is generated.

The power transmission side clock signal CK1 and the power reception side clock signal CK2 may be the same or different.
O At least one of the impedance converters 31 and 32 may be omitted.

The power transmitter 13 and the power receiver 23 have the same configuration, but are not limited to this, and may have different configurations.
Each capacitor 13b, 23b 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.
○ The target for mounting the power receiving device 21 is not limited to the vehicle, but is arbitrary.

O You may combine the structure of embodiment and said each other example suitably.
The power transmitter 13 may include a resonance circuit including the primary side coil 13a and the primary side capacitor 13b, and a primary side coupling coil that is coupled to the resonance circuit by electromagnetic induction. Similarly, the power receiver 23 may include a resonance circuit including a secondary coil 23a and a secondary capacitor 23b, and a secondary coupling coil coupled to the resonance circuit by electromagnetic induction.

Next, a preferable example that can be grasped from the embodiment and another example will be described below.
(A) When a predetermined frequency change condition is established, the change determination unit includes a change unit that changes the set frequency, and the abnormality determination unit is configured to change the set frequency after the change unit is changed. The non-contact power transmission apparatus according to claim 4, wherein the power transmission side detection frequency and the power reception side detection frequency are compared with the changed set frequency.

  (B) The power transmission device includes a primary side impedance conversion unit provided between the AC power source and the primary side coil, and the impedance of the primary side impedance conversion unit is the same as that of the primary side coil. The impedance from the output end of the AC power source to the load when the secondary coil is disposed at a predetermined reference position is set to approach a predetermined specific power source load impedance, The non-contact power transmission according to (a), wherein the frequency changing condition includes that an impedance from an output terminal of the AC power supply to the load is deviated by a predetermined allowable value or more with respect to the specific power supply load impedance. apparatus.

  (C) When the difference between the transmission-side detection frequency and the set frequency is more than the threshold difference, the abnormality determination unit generates an abnormality other than the abnormality of the power-transmission-side clock signal in the power transmission device. On the other hand, when the difference between the power transmission side detection frequency and the set frequency is less than the threshold difference, and the power reception side detection frequency and the set frequency are shifted by the threshold difference or more. The non-contact power transmission apparatus according to claim 4, wherein it is determined that an abnormality has occurred in the power transmission side clock signal or the power receiving device.

  (D) A power transmission side control microcomputer having the power transmission side clock circuit is provided, and the power transmission side control microcomputer and the power reception side control microcomputer are configured to be capable of wireless communication. The non-contact power transmission device according to any one of to (c).

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Power transmission apparatus, 12 ... AC power supply, 13a ... Primary side coil, 14 ... Microcomputer for power transmission side control, 15 ... Power transmission side clock circuit, 21 ... Power receiving apparatus, 23a ... Secondary side Coil, 26 ... Power-receiving-side control microcomputer, 27 ... Power-receiving-side clock circuit, 31, 32 ... Impedance converter, 41 ... Power-transmitting-side frequency detector, 42 ... Power-receiving-side frequency detector, f1 ... Power-transmitting-side detected frequency, f2 ... Receiving side detection frequency, ft ... set frequency, δfth ... threshold difference, CK1 ... power transmission side clock signal, CK2 ... reception side clock signal.

Claims (6)

An AC power source capable of outputting AC power, and a power transmission device having a primary coil to which the AC power is input;
A secondary coil capable of receiving the AC power input to the primary coil in a non-contact manner, and a power receiving device having a load to which the AC power received by the secondary coil is input;
In a non-contact power transmission device comprising:
The power transmission device includes a power transmission side clock circuit that outputs a power transmission side clock signal,
The AC power supply can output the AC power using the power transmission side clock signal,
The power receiving device detects a frequency of AC power from the secondary coil to the load by using a power receiving side control microcomputer having a power receiving side clock circuit that outputs a power receiving side clock signal and the power receiving side clock signal. A power-receiving-side frequency detection unit,
The non-contact power transmission apparatus includes an abnormality determination unit that determines whether or not an abnormality has occurred based on a detection result of the power reception side frequency detection unit. The power transmission device includes a power transmission side frequency detection unit that detects a frequency of AC power from the AC power source toward the primary coil, using the power transmission side clock signal.
The abnormality determination unit determines whether or not an abnormality has occurred based on a power transmission side detection frequency that is a detection result of the power transmission side frequency detection unit and a power reception side detection frequency that is a detection result of the power reception side frequency detection unit. Item 2. The non-contact power transmission device according to Item 1.   The said abnormality determination part determines with the abnormality having generate | occur | produced based on the difference of the said power transmission side detection frequency and the said power receiving side detection frequency becoming more than a predetermined threshold value difference. Non-contact power transmission device.   The abnormality determination unit determines that an abnormality has occurred based on a deviation of a predetermined threshold difference or more with respect to a predetermined set frequency with respect to the power transmission side detection frequency or the power reception side detection frequency. The non-contact power transmission device according to claim 2.   5. The apparatus according to claim 1, further comprising a stop control unit configured to stop the output of the AC power from the AC power supply when the abnormality determination unit determines that an abnormality has occurred. The contactless power transmission device described. Non-contact from a power transmission device having a power transmission side clock circuit that outputs a power transmission side clock signal, an AC power source that can output AC power using the power transmission side clock signal, and a primary coil to which the AC power is input. In the power receiving device capable of receiving the AC power in
A secondary coil capable of receiving the AC power input to the primary coil in a contactless manner;
A load to which AC power received by the secondary coil is input;
A power-receiving-side control microcomputer having a power-receiving-side clock circuit that outputs a power-receiving-side clock signal;
Using the power receiving side clock signal, a power receiving side frequency detecting unit for detecting a frequency of AC power from the secondary side coil toward the load;
And the presence or absence of abnormality is determined based on the detection result of the power reception side frequency detection unit.