JP2021083136A - Power reception device - Google Patents

Abstract

To correctly estimate the state of a battery during wireless power supply.SOLUTION: A power reception device 200 includes a secondary coil L2, a resonant coil Lx and a resonant capacitor Cx that form a resonant circuit together with the secondary coil L2, a power conversion unit 250 that converts AC current i flowing in the resonant circuit upon the reception of an AC magnetic field in the secondary coil L2 into DC current, and charges a battery 300 with this DC current, a power transmission instruction unit 212 that instructs the operation of a power transmission device 100, and a battery state estimation unit 211 that acquires the battery information about the state of the battery 300 and estimates the battery state. The power transmission instruction unit 212 instructs the transmission device to do the intermittent power supply of intermittently releasing the AC magnetic field from the primary coil in the power transmission device installed on the ground. The battery state estimation unit 211 estimates the battery state on the basis of the battery information acquired during the intermittent power supply of the power transmission device.SELECTED DRAWING: Figure 2

Description

The present invention relates to a power receiving device used in wireless power supply.

In recent years, in electric vehicles and the like, a wireless power supply system that wirelessly supplies power from a power transmission device provided on the ground side to a power receiving device provided on the vehicle side is being realized. In such a wireless power feeding system, a wireless power feeding technology using magnetic field resonance or magnetic field induction is drawing attention. In magnetic field induction, an alternating current is generated by passing an alternating current through a coil provided in a power transmission device on the ground side, and this magnetic field is received by a coil provided in a power receiving device on the vehicle side to generate an alternating current. By doing so, wireless power supply from the power transmission device to the power receiving device is realized. On the other hand, magnetic field resonance is the same as magnetic field induction in that coils are provided in the power transmitting device and the power receiving device, respectively, but by matching the frequency of the current flowing through the coil of the power transmitting device with the resonance frequency of the coil of the power receiving device. Resonance is generated between the power transmitting device and the power receiving device. As a result, the coil of the power transmission device and the coil of the power receiving device are magnetically coupled to realize highly efficient wireless power supply.

The following Patent Document 1 is known with respect to the above-mentioned wireless power feeding technology. In Patent Document 1, a high-frequency power supply, a primary coil that receives high-frequency power from the high-frequency power supply, and an abnormality detection object are provided, and are arranged in a non-contact manner apart from the primary coil, from the primary coil. It is provided with a secondary coil that receives electric power, a received electric power detecting means that detects the received electric power, and a determining means that determines the presence or absence of an abnormality based on the received electric power detected by the received electric power detecting means. An abnormality detection device characterized by the above is disclosed.

Japanese Unexamined Patent Publication No. 2012-29528

In the abnormality detecting device described in Patent Document 1, when the battery voltage reaches a preset threshold value during charging, it is determined that charging is completed. However, in general, the voltage during charging of a rechargeable battery changes according to the internal resistance even in the same charged state, and the internal resistance differs depending on the deteriorated state of the battery. Therefore, the method of Patent Document 1 cannot correctly estimate the state of the battery during wireless power supply.

The power receiving device according to the present invention receives an AC magnetic field emitted from a primary coil of a power transmitting device installed on the ground side and is wirelessly fed, and is connected to the secondary coil and the secondary coil. A resonance element that constitutes a resonance circuit having a predetermined resonance frequency together with the secondary coil, and an AC current that flows through the resonance circuit when the secondary coil receives the AC magnetic field are converted into a DC current, and the DC current is converted into a DC current. A power conversion unit that charges a battery using the power conversion unit, a power transmission instruction unit that instructs the operation of the power transmission device, and a battery that acquires battery information regarding the state of the battery and indicates the state of the battery based on the acquired battery information. A battery state estimation unit for estimating a state is provided, the power transmission instruction unit instructs the power transmission device to intermittently energize the AC magnetic field to intermittently emit the AC magnetic field from the primary coil, and the battery state estimation unit is the battery state estimation unit. The battery state is estimated based on the battery information acquired while the power transmission device is performing the intermittent energization.

According to the present invention, the state of the battery can be correctly estimated during wireless power supply.

It is a figure which shows the structure of the wireless power supply system which concerns on 1st Embodiment of this invention. It is a figure which shows the structural example of the power receiving device which concerns on 1st Embodiment of this invention. It is a figure which shows an example of the time chart at the time of charging of the wireless power supply system which concerns on 1st Embodiment of this invention. It is a figure which shows the processing flow of the wireless power supply system which concerns on 1st Embodiment of this invention. It is a figure which shows the process flow of the CC mode intermittent energization process in the power receiving apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the processing flow of the CV mode energization processing in the power receiving apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the process flow of the CV mode intermittent energization process in the power receiving apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the wireless power supply system which concerns on 2nd Embodiment of this invention. It is a figure which shows the structural example of the power receiving device which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the power receiving device according to the present invention will be described with reference to the drawings.

− First Embodiment −
FIG. 1 is a diagram showing a configuration of a wireless power supply system 1 according to a first embodiment of the present invention. The wireless power supply system 1 shown in FIG. 1 is used for wireless power supply to a vehicle such as an electric vehicle, and is a power transmission device 100 installed on the ground side near the vehicle and a power receiving device mounted on the vehicle side, respectively. It has 200, a battery 300, a load 400, and a battery monitoring device 500.

The power transmission device 100 includes a power transmission control unit 110, a communication unit 120, an AC power supply 130, a power conversion unit 140, and a primary coil L1. The power transmission control unit 110 controls the entire power transmission device 100 by controlling the operations of the communication unit 120 and the power conversion unit 140.

The communication unit 120 performs wireless communication with the communication unit 220 included in the power receiving device 200 under the control of the power transmission control unit 110. By the wireless communication between the communication unit 120 and the communication unit 220, various information necessary for wireless power supply is exchanged between the power transmission device 100 and the power reception device 200. For example, information such as the frequency of the alternating current flowing through the primary coil L1, that is, the frequency of the alternating magnetic field emitted from the primary coil L1 is transmitted from the communication unit 120 to the communication unit 220. In addition, information such as the charging state (SOC) and deterioration state of the battery 300 and the allowable current during charging is transmitted from the communication unit 220 to the communication unit 120.

The AC power supply 130 is, for example, a commercial power supply, and supplies a predetermined AC power to the power conversion unit 140. The power conversion unit 140 outputs an alternating current having a predetermined frequency and current value to the primary coil L1 by using the alternating current power supplied from the alternating current power supply 130 under the control of the power transmission control unit 110. The primary coil L1 is installed on the ground side located below the vehicle, and emits an alternating magnetic field corresponding to the alternating current flowing from the power conversion unit 140 toward the vehicle in the air. As a result, wireless power is supplied to the vehicle.

The power receiving device 200 includes a power receiving control unit 210, a communication unit 220, a drive control unit 240, a power conversion unit 250, a constant current conversion unit 260, a voltmeter 270, a secondary coil L2, a resonance coil Lx, and a resonance capacitor Cx. The resonance coil Lx and the resonance capacitor Cx are connected to the secondary coil L2, and form a resonance circuit together with the secondary coil L2. The resonance frequency of this resonance circuit is determined according to the inductance of the secondary coil L2 and the resonance coil Lx, and the capacitance value of the resonance capacitor Cx. The resonance coil Lx and the resonance capacitor Cx may each be composed of a plurality of elements. Further, a part or all of the resonance coil Lx may be substituted with the inductance of the secondary coil L2.

The power receiving control unit 210 controls the entire power receiving device 200 by controlling the operations of the communication unit 220 and the drive control unit 240. The communication unit 220 performs wireless communication with the communication unit 120 included in the power transmission device 100 under the control of the power reception control unit 210, and exchanges various information as described above between the power transmission device 100 and the power reception device 200. Send and receive. Information such as the frequency of the alternating current flowing through the primary coil L1 received by the communication unit 220 is output from the communication unit 220 to the power reception control unit 210.

The drive control unit 240 controls the switching operation of a plurality of switching elements included in the power conversion unit 250 under the control of the power reception control unit 210.

The power conversion unit 250 has a plurality of switching elements, and by switching the plurality of switching elements, the AC current flowing in the resonance circuit is controlled and rectified, and the AC power (AC current) is converted to a DC power. Convert to (direct current).

The constant current conversion unit 260 suppresses fluctuations in the direct current output from the power conversion unit 250 to convert the current to a constant current. A chargeable / dischargeable battery 300 is connected to the constant current conversion unit 260, and the battery 300 is charged using a direct current output from the power conversion unit 250 and converted to a constant current by the constant current conversion unit 260. .. Between the power conversion unit 250 and the constant current conversion unit 260, a smoothing capacitor C0 for smoothing the input voltage to the constant current conversion unit 260 and a voltage for measuring the input voltage to the constant current conversion unit 260 are provided. A total of 270 are connected.

The battery 300 is configured by connecting a plurality of chargeable and discharging cells in series or in series and parallel. A load 400 is connected to the battery 300. The load 400 utilizes the DC power charged in the battery 300 to provide various functions related to the operation of the vehicle. The load 400 includes, for example, an AC motor for driving a vehicle, an inverter that converts the DC power of the battery 300 into AC power, and supplies the AC power to the AC motor.

The battery monitoring device 500 is connected to the battery 300, and acquires various information for monitoring the state of the battery 300 from the battery 300. For example, the battery monitoring device 500 acquires information such as the voltage, current, charging state (SOC), and internal resistance value of the battery 300, and the voltage and internal resistance value of each cell constituting the battery 300. Then, these acquired information are put together and output to the power receiving control unit 210 as battery information. The battery monitoring device 500 transmits battery information regarding the battery 300 to the power receiving control unit 210 of the power receiving device 200 via an in-vehicle communication network such as CAN (Controller Area Network).

Next, among the wireless power feeding systems 1 of FIG. 1, the details of the power receiving device 200 to which the present invention is applied will be described. FIG. 2 is a diagram showing a configuration example of the power receiving device 200 according to the first embodiment of the present invention. In addition to the configuration of the power receiving device 200, FIG. 2 also shows the battery 300 and the battery monitoring device 500.

The power conversion unit 250 has two MOS transistors (MOSFETs) Q1 and Q2 connected in series and two MOS transistors Q3 and Q4 connected in series. The series circuit of the MOS transistors Q1 and Q2 and the series circuit of the MOS transistors Q3 and Q4 are connected in parallel with each other with respect to the smoothing capacitor C0. The MOS transistors Q1 to Q4 each perform a switching operation of switching between the source and drain from the conductive state to the disconnected state or from the disconnected state to the conductive state according to the gate drive signal from the drive control unit 240. By this switching operation, the MOS transistors Q1 and Q3 can function as switching elements for the upper arm, and the MOS transistors Q2 and Q4 can function as switching elements for the lower arm, respectively. A resonance circuit including a secondary coil L2 is connected to the connection point O1 between the MOS transistors Q1 and Q2 and the connection point O2 between the MOS transistors Q3 and Q4, respectively. Therefore, by switching the MOS transistors Q1 to Q4 at appropriate timings, it is possible to control and rectify the alternating current i flowing in the resonance circuit.

The constant current conversion unit 260 has two MOS transistors X1 and X2 connected in series. The MOS transistors X1 and X2 each perform a switching operation of switching between the source and drain from the conductive state to the disconnected state or from the disconnected state to the conductive state according to the gate drive signal from the drive control unit 240. The series circuit of the MOS transistors X1 and X2 is connected to the power conversion unit 250 in parallel with the smoothing capacitor C0. Further, one end side of the coil Lb is connected between the MOS transistors X1 and X2, and the battery 300 is connected between the other end side of the coil Lb and the MOS transistor X2. Therefore, by switching the MOS transistors X1 and X2 at appropriate timings, the current flowing from the power converter 250 to the coil Lb via the MOS transistors X1 and X2 is controlled to be substantially constant, and the battery 300 is charged. Can be done.

The power receiving control unit 210 includes a battery state estimation unit 211, a power transmission instruction unit 212, and a drive instruction unit 213.

The battery state estimation unit 211 acquires the above-mentioned battery information output from the battery monitoring device 500, and estimates the state (battery state) of the battery 300 based on the acquired battery information. The specific contents of the battery state estimated by the battery state estimation unit 211 will be described later. The battery state estimation result by the battery state estimation unit 211 is output to the power transmission instruction unit 212 and the drive instruction unit 213.

The power transmission instruction unit 212 gives an operation instruction to the power transmission device 100 based on the estimation result of the battery state by the battery state estimation unit 211 and the input voltage Vs to the constant current conversion unit 260 detected by the voltmeter 270. .. The operation instruction to the power transmission device 100 by the power transmission instruction unit 212 is output to the communication unit 220, and is transmitted by the communication unit 220 to the communication unit 120 of the power transmission device 100. Further, the content of the operation instruction transmitted to the power transmission device 100 is also output from the power transmission instruction unit 212 to the drive instruction unit 213.

The drive instruction unit 213 generates a basic drive signal Sr based on the estimation result of the battery state by the battery state estimation unit 211 and the operation instruction content to the power transmission device 100 by the power transmission instruction unit 212, and causes the drive control unit 240 to generate the basic drive signal Sr. Output. The basic drive signal Sr is an AC signal that is output from the drive control unit 240 to the power conversion unit 250 and is a source of a gate drive signal that controls the switching operation of the MOS transistors Q1 to Q4, and its frequency is the primary of the power transmission device 100. It is determined according to the frequency of the current flowing through the coil L1. Specifically, the frequency information of the alternating current flowing through the primary coil L1 instructed by the power transmission instruction unit 212 to the power transmission device 100 is input from the power transmission instruction unit 212 to the power reception control unit 210. The drive instruction unit 213 generates a basic drive signal Sr based on this frequency information and outputs it to the drive control unit 240. The basic drive signal Sr is, for example, a combination of four square waves corresponding to MOS transistors Q1 to Q4, and has an H level corresponding to on (conduction state) and an L level corresponding to off (disconnection state). Is alternately repeated at the same frequency as the power transmission device 100. However, in order to prevent the MOS transistors Q1 and Q2 and Q3 and Q4 from being turned on at the same time, a predetermined protection period is provided between the H levels of the two square waves in each combination of the corresponding square waves.

The drive control unit 240 includes a drive signal generation unit 243 and a gate drive circuit 244.

The basic drive signal Sr is input from the drive instruction unit 213 to the drive signal generation unit 243. The drive signal generation unit 243 generates a charge drive signal Sc based on the input basic drive signal Sr. Then, the generated charge drive signal Sc is output to the gate drive circuit 244.

The gate drive circuit 244 outputs a gate drive signal based on the charge drive signal Sc input from the drive signal generation unit 243 to the gate terminals of the MOS transistors Q1 to Q4, X1 and X2, respectively, and the gate drive circuit 244 outputs the gate drive signals to the gate terminals of the MOS transistors Q1 to Q4, X1 and X1, respectively. Each X2 is switched. As a result, in the power conversion unit 250, the MOS transistors Q1 to Q4 function as switching elements, respectively, and control of the AC current i flowing in the resonance circuit according to the AC magnetic field emitted from the primary coil L1 and the DC power from the AC power. Conversion to is done. Further, in the constant current conversion unit 260, the MOS transistors X1 and X2 function as switching elements, respectively, and the direct current output from the power conversion unit 250 is converted to a constant current and output to the battery 300.

The power receiving device 200 of the present embodiment can charge the battery 300 by receiving wireless power supply from the power transmission device 100 by performing the operations as described above.

Next, the flow of wireless power supply using the wireless power supply system 1 will be described. FIG. 3 is a diagram showing an example of a time chart at the time of charging of the wireless power supply system 1 according to the first embodiment of the present invention. In FIG. 3A, the vertical axis represents the magnitude of the charging current flowing through the battery 300, and the horizontal axis represents the charging time. Further, FIG. 3B is a part of FIG. 3A enlarged in the horizontal direction, and the timing of the battery information output from the battery monitoring device 500 is shown side by side.

As shown in FIG. 3A, when charging of the battery 300 is started, the battery 300 is charged in a constant current (CC) mode in which the charging current is constant in the first period. The magnitude of the charging current at this time is determined according to the allowable current of the battery 300 at the time of charging or the rated current of the power transmission device 100. Hereinafter, the length t _{CC_CNT} of this period is referred to as the CC mode continuous energization time.

When the charging state (SOC) of the battery 300 reaches a predetermined value, for example, 60% or more during charging in the CC mode, the magnitude of the charging current flowing through the battery 300 does not change, but the energization of the battery 300 is intermittent. Be done. Here, electric vehicles such as electric vehicles rarely use up the battery of the energy source, and are generally connected to the charging device with a sufficient remaining amount. Further, as will be described later, battery charging has a CC mode in which the energizing current is kept constant and a CV mode in which the battery voltage is kept constant. CC and CV have the remaining amount (SOC) as an example. It often switches at about 80%. The operation of intermittently interrupting the charging current described above is performed under the condition that the initial remaining amount when connected to the charging device is not excessively low and the SOC during the CC mode period is 80% or less. The interruption of the current is set to _{t OFF} = t _ON , for example, as shown in FIG. 3, assuming that the interruption time for each time is t _OFF and the energization time is t _ON. However, t _OFF and t _ON do not necessarily have to match. In the following, the time t _{CC_DISC in} which the battery 300 is intermittently energized in the CC mode will be referred to as the CC mode intermittent energization time. In the example shown in FIG. 3, the battery 300 is energized a total of 6 times (P1 to _{P6) during the CC mode intermittent energization time t CC_DISC.}

Here, if the combination of the interruption time t _OFF and the energization time t _ON during intermittent energization is the cycle time t _P , it is expressed as _{t P} = t _OFF + t _ON. The enlarged cycle time t _P is shown in FIG. 3 (b). In FIG. 3B, R _{1 to} R ₂₀ represent examples of timing at which battery information is output from the battery monitoring device 500 during the cycle time t _P. In the example shown in FIG. 3B, the battery information is output 10 times from the battery monitoring device 500 at each of the _{cutoff time t OFF} and the energization time t _ON. The number of times the battery information is output during the cutoff time t _OFF and the energization time t _ON is not limited to the above example, and can be arbitrarily set according to the required accuracy for the battery state estimation result performed by the battery state estimation unit 211. ..

_{The charging time t CC} of the battery 300 in the CC mode is the total value of the CC mode continuous energizing time t _{CC_CNT} and the CC mode intermittent energizing time t _{CC_DISC. For example, assuming} that the number of times the battery information is output at each of the cutoff time t OFF and the energization time t _ON is 10 times and the output cycle of the battery information is 1 second as in the example of FIG. 3B, the cycle The time t _P is calculated as t _P = 20 (seconds). _{Therefore, assuming} that the number of intermittent times is 6 as in the example of FIG. 3A, the CC mode intermittent energization time t CC_DISC is required to be 20 × 6 = 120 (seconds). The cycle time t _P (cutoff time t _OFF and energization time t _ON ) is preset according to the number of times the battery information is output and the output cycle.

On the other hand, the length of the CC mode continuous energization time t _{CC_CNT} varies depending on the magnitude of the charging current and the charging state of the battery 300 before charging, but generally about 1 hour is required. Therefore, the CC mode intermittent energization time t _{CC_DISC} is sufficiently shorter than the CC mode continuous energization time t _{CC_CNT} , and the effect on the _{charging time t CC is small.}

When the CC mode intermittent energization time t _{CC_DISC} elapses, the charging in the CC mode is completed, and the battery 300 is charged in the constant voltage (CV) mode in which the charging current is changed according to the state of the battery being charged. The magnitude of the charging current at this time is determined so that the voltage of the battery 300 being charged becomes constant. Hereinafter, the length t _{CV_CNT} of this period is referred to as the CV mode continuous energization time.

When the cell voltage of any of the batteries 300 reaches a predetermined value, for example, 4.2 V or more during charging in the CV mode, the battery 300 is intermittently energized as in the above-mentioned CC mode intermittent energization time t _{CC_DISC.} To. Assuming that the cutoff time for each operation is t _{OFF *} and the energization time is t _{ON *} , for example, t _{OFF *} = t _{ON *} is set as shown in FIG. However, t _{OFF *} and t _{ON *} do not necessarily have to match. In the following, the time t _{CV_DISC in} which the battery 300 is intermittently energized in the CV mode will be referred to as the CV mode intermittent energization time. The above-mentioned CC mode intermittent energization time t _{CC_DISC} cutoff time t _OFF and energization time t _ON and this CV mode intermittent energization time t _{CV_DISC} cutoff time t _{OFF *} and energization time t _{ON *} are the same, respectively. It may be a different value.

CV mode intermittent energization time t _{The number of intermittent energization in CV_DISC} is determined according to the battery state. Details will be described later. _{The charging time t CV} of the battery 300 in the CV mode is the total value of the above-mentioned CV mode continuous energizing time t _{CV_CNT} and the CV mode intermittent energizing time t _{CV_DISC.} When the CV mode intermittent energization time t _{CV_DISC} elapses, the charging of the battery 300 is completed.

FIG. 4 is a diagram showing a processing flow of the wireless power supply system 1 according to the embodiment of the present invention. When the vehicle equipped with the power receiving device 200, the battery 300, the load 400, and the battery monitoring device 500 is parked at a predetermined charging position, the processing flow of FIG. 4 is started in the wireless power supply system 1.

In step S10, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. In step S20, it is determined whether to charge the battery 300 in CC mode or CV mode based on the battery information acquired in step S10. Here, for example, the value of SOC included in the acquired battery information is compared with a predetermined threshold value, for example, 80%. As a result, if the SOC is less than the threshold value, it is determined to be the CC mode and the process proceeds to step S30.

In step S30, the power transmission instruction unit 212 determines the current command value I _CC and the frequency F _CC when charging the battery 300 in the CC mode. Here, for example, the communication unit 220 is used to communicate with the power transmission device 100 to acquire the value of the rated current of the power transmission device 100. Then, the value of the permissible current included in the battery information acquired in step S10 is compared with the value of the rated current of the power transmission device 100, and the lower value is determined as the current command value _ICC . The allowable current value of the battery 300 may be stored in the power transmission instruction unit 212 in advance, or may be determined based on the internal resistance value and the deterioration state included in the battery information. _{Further, the frequency F CC} is determined based on the resonance frequency of the resonance circuit including the secondary coil L2 in the power receiving device 200 stored in advance and the transmission frequency acquired from the power transmission device 100.

In step S40, the power transmission instruction unit 212 calculates _{the charging time t CC of the battery 300 in the CC mode.} Here, for example, the charging time t _CC is calculated using the following equation (1). In the formula (1), Q ^ and SOC ₀ represent the battery capacity and the SOC value included in the battery information acquired in step S10, respectively. Further, SOC _L represents the threshold value of SOC used in the determination in step S20.
t _CC = Q ^ ・ (SOC _{L − SOC 0} ) / I _CC・ ・ ・ (1)

After calculating the charging time t _CC in step S40, the power transmission instruction unit 212 determines the CC mode continuous energizing time t _{CC_CNT} and the CC mode intermittent energizing time t _{CC_DISC based on the value of the charging time t CC} . Here, for example, the CC mode intermittent energization time t _{CC_DISC} is determined first with a predetermined value, and the determined CC mode intermittent energization time t _{CC_DISC} is subtracted from the charging time t _CC to determine the CC mode continuous energization time t _{CC_CNT.} To do.

In step S50, the power transmission instruction unit 212 gives an instruction to start power transmission to the power transmission device 100. Here, by transmitting the current command value I _CC and the frequency F _CC determined in step S30 to the power transmission device 100 using the communication unit 220, an instruction to start power transmission to the power transmission device 100 is given. When this power transmission start instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 causes a current to flow through the primary coil L1 according to the _{designated current command values I CC} and frequency F _{CC to generate an alternating magnetic field.} As a result, wireless power supply from the power transmitting device 100 to the power receiving device 200 is started.

In step S60, it is determined whether or not _{the charging time t CC} in the CC mode calculated in step S40 has elapsed from that time, based on the time when the power transmission start instruction is given in step S50 and the wireless power supply is started. As a result, _{if it is determined that the charging time t CC} has not yet elapsed, the process proceeds to step S70, and if it is determined that the charging time t CC has not elapsed, the process proceeds to step S100.

In step S70, it is determined whether or not _{the CC mode continuous energization time t CC_CNT} determined in step S40 has elapsed from that time based on the time when the power transmission start instruction is given in step S50 and the wireless power supply is started. As a result, if it is determined that the CC mode continuous energization time t _{CC_CNT} has not yet elapsed, the process proceeds to step S80, and if it is determined that the CC mode continuous energization time has elapsed, the process proceeds to step S90.

In step S80, in the power receiving device 200, the power conversion unit 250 and the constant current conversion unit 260 are driven according to the alternating current i that receives the alternating magnetic field emitted from the primary coil L1 and flows in the resonance circuit including the secondary coil L2. Perform control processing. Here, the drive instruction unit 213 of the power reception control unit 210, the drive signal generation unit 243 of the drive control unit 240, and the gate drive circuit 244 each perform the above-mentioned processing to receive power from the power transmission device 100. Drive control of the power conversion unit 250 and the constant current conversion unit 260 according to the alternating current is performed. As a result, the battery 300 is charged in the constant current (CC) mode.

In step S90, the power receiving device 200 executes a CC mode intermittent energization process for interrupting the energization of the battery 300 in the CC mode. By this CC mode intermittent energization process, the AC magnetic field is intermittently emitted from the primary coil L1 in the power transmission device 100, and the battery state is estimated in the power receiving device 200. The specific process flow of the CC mode intermittent energization process will be described later with reference to the process flow of FIG.

After executing the process of step S80 or step S90, the process returns to step S60, and the above process is repeated until it is determined in _{step S60 that the charging time t CC in the CC mode has elapsed.}

When it is determined in step S60 that the charging time t _CC in the CC mode has elapsed, in step S100, the battery state estimation unit 211 averages the estimation results _{of the battery capacity Q x of the battery 300 after charging in the CC mode.} And notify the battery monitoring device 500. _{The estimation result of the battery capacity Q x} notified here is obtained by _{the battery state estimation unit 211 for each cycle time t P} described above in the CC mode intermittent energization process in step S90, and the number is intermittent. Equal to the number of times the power was turned on. That is, in the example shown in FIG. 3, since the number of times of intermittent energization is 6, the CC mode intermittent energization process of step S90 is performed 6 times, so that the estimation result _{of the battery capacity Q x is obtained when step S100 is executed.} Six have been obtained. In step S60, _{the average value of the six battery capacities Q x} is obtained and notified to the battery monitoring device 500. After notifying the battery monitoring device 500 of the estimation result of the battery capacity Q _{x in} step S100, the charging mode of the battery 300 is switched from the CC mode to the CV mode, and the process proceeds to step S110.

In step S110, the power receiving device 200 executes a CV mode energization process for energizing the battery 300 in the CV mode. By this CV mode energization process, an alternating magnetic field is emitted from the primary coil L1 in the power transmission device 100, and the battery 300 is charged and the battery state is estimated in the power receiving device 200. The specific process flow of the CV mode energization process will be described later with reference to the process flow of FIG.

When the CV mode energization process in step S110 is completed, the process flow of FIG. 4 is completed. As a result, the wireless power supply of the wireless power supply system 1 is completed, and the charging of the battery 300 is completed.

Next, the CC mode intermittent energization process performed in step S90 of FIG. 4 will be described. FIG. 5 is a diagram showing a processing flow of CC mode intermittent energization processing in the power receiving device 200 according to the embodiment of the present invention.

In step S210, the power transmission instruction unit 212 changes _{the frequency F CC determined in step S30 of FIG.} The changed frequency F _CC value is transmitted to the power transmission device 100 using the communication unit 220, and the frequency of the current flowing through the primary coil L1 in the power transmission device 100 is changed. Further, the drive frequency when the drive instruction unit 213 performs drive control of the power conversion unit 250 and the constant current conversion unit 260 is changed according to the changed value of the frequency F _CC. As a result, the efficiency of wireless power supply from the power transmission device 100 to the power receiving device 200 is lowered, the power received by the power receiving device 200 is reduced in advance, and the counter electromotive force generated in the power receiving device 200 when the power transmission is stopped is suppressed. To. _{However, the change of the frequency F CC} may be omitted without executing the process of step S210.

In step S220, the power transmission instruction unit 212 transmits a power transmission stop instruction to the power transmission device 100 using the communication unit 220. When this power transmission stop instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 cuts off the current to the primary coil L1 and stops the generation of the alternating magnetic field. As a result, the wireless power supply from the power transmission device 100 to the power receiving device 200 is interrupted, and the cutoff time t _OFF is started in _{the CC mode intermittent energization time t CC_DISC.} At this time, in order to suppress the counter electromotive force generated in the power receiving device 200, the current to the primary coil L1 may be gradually reduced instead of being cut off suddenly.

In step S230, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. As described above, this battery information is transmitted from the battery monitoring device 500 at a predetermined cycle, for example, every second.

In step S240, the battery state estimation unit 211 calculates _{the average values OCV j / OFF} and SOC _{j / OFF} of the open circuit voltage (OCV) and the charge state (SOC) of the battery 300 in _{the jth cutoff time tOFF period.} .. Here, by averaging the OCV and SOC values of the battery 300 included in the battery information acquired in step S230 _{within the cutoff time t OFF , the average values OCV j / OFF} and SOC _j indicating the battery state of the battery 300 are shown. Calculate _{/ OFF.} In addition, j represents the number of times that the CC mode intermittent energization process of FIG. 5 was performed in step S90 in the process flow of FIG. 4, that is, the number of times of intermittent energization. In the example of FIG. 3, since the number of intermittent energization is 6 times in total, j = 1 to 6.

In step S250, it is determined whether or not the _{cutoff time t OFF} has elapsed from the time when the wireless power supply is interrupted by issuing the power transmission stop instruction in step S220. As described above, the cutoff time t _OFF is preset according to the number of times the battery information is output and the output cycle. As a result, _{if it is determined that the cutoff time t OFF} has not yet passed, the process returns to step S230 to continue the acquisition of battery information and the calculation of the average values OCV _{j / OFF} and SOC _{j / OFF} , and it is determined that the battery information has passed. In the case, the process proceeds to step S260.

_{In step S260, the average values OCV j / OFF} and SOC _{j / OFF} finally calculated in step S240 are stored in the power receiving control unit 210. _{As a result, the average OCV value OCV j / OFF} and the average SOC _{j / OFF} of the battery 300 are obtained by using all the battery information output from the battery monitoring device 500 at the jth cutoff time t _OFF. Can be done.

In step S270, the power transmission instruction unit 212 _{returns the frequency F CC} changed in step S210 to the original value. When the value of this frequency F _CC is transmitted to the power transmission device 100 using the communication unit 220, the frequency of the current flowing through the primary coil L1 in the power transmission device 100 becomes the frequency F _{CC determined in step S30 of FIG.} Returned. _{If the change of the frequency F CC} is omitted without executing the process of step S210 as described above, the process of step S270 is unnecessary.

In step S280, the power transmission instruction unit 212 transmits a power transmission start instruction to the power transmission device 100 using the communication unit 220. When this power transmission start instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 causes an AC magnetic field to be generated by passing a current through the primary coil L1 as in step S50 of FIG. As a result, the wireless power supply from the power transmitting device 100 to the power receiving device 200 is restarted, and the energizing time t _ON is started in _{the CC mode intermittent energizing time t CC_DISC.}

In step S290, in the power receiving device 200, the power conversion unit 250 and the constant current conversion unit 260 are driven according to the alternating current i that receives the alternating magnetic field emitted from the primary coil L1 and flows through the resonance circuit including the secondary coil L2. Perform control processing. Here, as in step S80 of FIG. 4, the drive instruction unit 213 of the power reception control unit 210, the drive signal generation unit 243 of the drive control unit 240, and the gate drive circuit 244 respond to the alternating current received from the power transmission device 100. The drive control of the power conversion unit 250 and the constant current conversion unit 260 is performed. As a result, the battery 300 is charged in the constant current (CC) mode.

In step S300, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. As described above, this battery information is transmitted from the battery monitoring device 500 at a predetermined cycle, for example, every second.

In step S310, the battery state estimation unit 211 calculates _{the current integral value ΔQ j} of the battery 300 during the energization time t _{ON period by the jth energization P j.} Here, the integrated current value ΔQ _j is calculated by integrating the charging current value of the battery 300 included in the battery information acquired in step S300 _{within the energization time t ON.}

In step S320, it is determined whether or not the _{energization time t ON} has elapsed from that time, based on the time when the power transmission start instruction is given in step S280 and the wireless power supply is restarted. As described above, the energization time t _ON is preset according to the number of times the battery information is output and the output cycle. As a result, _{if it is determined that the energization time t ON} has not yet elapsed, the process returns to step S290 _{to continue acquiring battery information and calculating the current integral value ΔQ j} , and if it is determined that the energization time t ON has elapsed, the process proceeds to step S330. ..

In step S330, the battery state estimation unit 211 calculates _{the change ΔSOC j} of the SOC of the battery 300 in the _{jth energization P j.} Here, the following equation is used using the j-th SOC average value SOC _{j / OFF} stored in step S260 and the (j-1) -th SOC average value SOC _{j-1 / OFF stored last time.} Calculate _{ΔSOC j according} to (2).
ΔSOC _j ＝ SOC _{j / OFF − SOC j-1 / OFF}・ ・ ・ (2)

In step S340, the battery state estimation unit 211 estimates the battery capacity Q _x of the battery 300. Here, the battery state of the battery 300 is determined by calculating the following equation (3) using the current integral value ΔQ _j calculated in step S310 and the change in SOC ΔSOC _{j calculated in step S330.} Estimate the indicated battery capacity Q _x.
Q _x = ΔQ _j / ΔSOC _j・ ・ ・ (3)

When the battery capacity Q _x can be estimated in step S340, the CC mode intermittent energization process shown in the process flow of FIG. 5 is terminated, and the process returns to step S60 of FIG.

Next, the CV mode energization process carried out in step S110 of FIG. 4 will be described. FIG. 6 is a diagram showing a processing flow of CV mode energization processing in the power receiving device 200 according to the embodiment of the present invention.

In step S410, similarly to step S210 of FIG. 5, the power transmission instruction unit 212 changes _{the frequency F CC determined in step S30 of FIG.} The changed frequency F _CC value is transmitted to the power transmission device 100 using the communication unit 220, and the frequency of the current flowing through the primary coil L1 in the power transmission device 100 is changed.

In step S420, similarly to step S220 of FIG. 5, the power transmission instruction unit 212 transmits a power transmission stop instruction to the power transmission device 100 using the communication unit 220. When this power transmission stop instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 cuts off the current to the primary coil L1 and stops the generation of the alternating magnetic field.

In step S430, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. As described above, this battery information is transmitted from the battery monitoring device 500 at a predetermined cycle, for example, every second.

In step S440, it is determined whether or not there is a cell having a cell voltage equal to or higher than a predetermined value in the battery 300. Here, it is determined whether or not the voltage of each cell included in the battery information acquired in step S430, that is, the OCV of each cell has a value equal to or higher than a predetermined value. As a result, if there is even one cell voltage equal to or higher than a predetermined value, the process proceeds to step S510, and if not, the process proceeds to step S450. The predetermined value used in the determination in step S440 is a cell voltage value for determining whether or not each cell is in a state before reaching an overvoltage, and a value such as 4.2 V is set. To.

In step S450, the maximum of each cell voltage in the battery 300 is specified as the _{maximum cell voltage OCV m.} Here, the maximum voltage of each cell included in the latest battery information acquired in step S430 or S490 described later is selected and specified as the _{maximum cell voltage OCV m.} Since the battery 300 is being charged, each cell voltage of the battery information acquired in step S490 represents a closed circuit voltage (CCV) rather than an open circuit voltage (OCV) of each cell. Therefore, in this case, it is necessary _{to convert CCV to OCV and specify the maximum cell voltage OCV m.} For example, it is possible to convert the CCV of each cell into OCV based on the charging current value included in the battery information and the internal resistance value of each cell.

In step S460, the power transmission instruction unit 212 determines the current command value I _CV and the frequency F _CV when the battery 300 is continuously charged in the CV mode. _{Here, the current command value I CV} is calculated by the following equation (4) using the maximum cell voltage OCV _{m specified in step S450.} In the formula (4), R _{cell represents the internal resistance value of the cell in which the maximum cell voltage OCV m} is obtained among the internal resistance values of each cell included in the battery information acquired in step S430 or S490. Further, Vmax is a predetermined allowable maximum voltage value for each cell, and a value such as 4.2V is set.
I _CV = (Vmax-OCV _m ) / R _cell ^ ・ ・ ・ (4)

On the other hand, the frequency F _CV is set by, for example, a value stored in advance. _{At this time, the frequency F CV} may be set with a value different from the _{frequency F CC} in the CC mode described above. By doing so, it is possible to prevent an excessive charging current from flowing to the battery 300 in the CV mode, and to improve safety.

_{After determining the current command value I CV} and the frequency F _CV during continuous energization in the CV mode as described above, in step S470, the power transmission instruction unit 212 gives an instruction to start power transmission to the power transmission device 100. Here, the current command value I _CV and the frequency F _CV determined in step S460 are transmitted to the power transmission device 100 by using the communication unit 220 to instruct the power transmission device 100 to start power transmission. When this power transmission start instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 causes a current to flow through the primary coil L1 according to the _{designated current command value I CV} and frequency F _{CV to generate an alternating magnetic field.} As a result, the wireless power supply from the power transmission device 100 to the power reception device 200 is restarted, and the CV mode continuous energization time t _{CV_CNT} is started.

In step S480, in the power receiving device 200, the power conversion unit 250 and the constant current conversion unit 260 are driven according to the alternating current i that receives the alternating magnetic field emitted from the primary coil L1 and flows through the resonance circuit including the secondary coil L2. Perform control processing. Here, as in step S80 of FIG. 4 and step S290 of FIG. 5, in the drive instruction unit 213 of the power receiving control unit 210, the drive signal generation unit 243 of the drive control unit 240, and the gate drive circuit 244, the power transmission device 100 Drive control of the power conversion unit 250 and the constant current conversion unit 260 according to the received AC current is performed. As a result, the battery 300 is charged in the constant voltage (CV) mode.

In step S490, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. As described above, this battery information is transmitted from the battery monitoring device 500 at a predetermined cycle, for example, every second.

In step S500, the battery state estimation unit 211 calculates the voltage of each cell of the battery 300. Here, the voltage of each cell is calculated by converting the CCV of each cell represented by the battery information acquired in step S490 into OCV by the same method as in step S450 described above.

After calculating the cell voltage in step S500, the process returns to step S440, and the determination as described above is performed again in step S440. In the determination at this time, each cell voltage obtained in step S500 is used. As a result, until it is determined in step S440 that there is a cell voltage equal to or higher than a predetermined value, the processes of steps S450 to S500 are repeated to continue continuous energization of the battery 300 in the constant voltage (CV) mode.

On the other hand, if it is determined in step S440 that there is a cell voltage equal to or higher than a predetermined value, the process proceeds to step S510. In step S510, the power receiving device 200 executes a CV mode intermittent energization process for interrupting the energization of the battery 300 in the CV mode. By this CV mode intermittent energization process, the AC magnetic field is intermittently emitted from the primary coil L1 in the power transmission device 100, and the battery state is estimated in the power receiving device 200. The specific processing flow of the CV mode intermittent energization processing will be described below with reference to the processing flow of FIG.

When the CV mode intermittent energization process is executed in step S510, the CV mode energization process shown in the processing flow of FIG. 6 is terminated, and the charging of the battery 300 is completed.

Next, the CV mode intermittent energization process carried out in step S510 of FIG. 5 will be described. FIG. 7 is a diagram showing a processing flow of CV mode intermittent energization processing in the power receiving device 200 according to the embodiment of the present invention.

In step S610, the power transmission instruction unit 212 transmits a power transmission stop instruction to the power transmission device 100 using the communication unit 220. When this power transmission stop instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 cuts off the current to the primary coil L1 and stops the generation of the alternating magnetic field. As a result, the wireless power supply from the power transmission device 100 to the power receiving device 200 is interrupted, and the cutoff time t _{OFF *} is started in _{the CV mode intermittent energization time t CV_DISC.}

In step S620, the battery state estimation unit 211 acquires battery information from the battery monitoring device 500. As described above, this battery information is transmitted from the battery monitoring device 500 at a predetermined cycle, for example, every second.

In step S630, the battery state estimation unit 211 calculates the time average value OCV _Ave of all cell voltages and the time average value OCV _mAve of the _{maximum cell voltage during the current cutoff time t OFF * period.} Here, the average value of the voltages of all the cells of the battery 300 included in the battery information acquired in step S620 is obtained, and the average value is _{averaged within the cutoff time t OFF *} to change the battery state of the battery 300. Calculate _{the time average OCV Ave} of all cell voltages shown. In addition, by selecting the maximum voltage of each cell _{and averaging the cell voltage within the cutoff time t OFF * , the time average value OCV mAve} of the maximum cell voltage indicating the battery status of the battery 300 can be obtained. calculate.

In step S640, it is determined whether or not the _{cutoff time t OFF *} has elapsed from the time when the wireless power supply is interrupted by issuing the power transmission stop instruction in step S610. The cutoff time t _{OFF *} is set in advance according to the number of times the battery information is output and the output cycle, as in the case of the cutoff time t _{OFF in the CC mode.} As a result, _{if it is determined that the cutoff time t OFF *} has not yet passed, the process returns to step S620 to acquire the battery information and the time average value OCV _Ave of all cell voltages and the time average value OCV _mAve of the maximum cell voltage. The calculation is continued, and if it is determined that the calculation has passed, the process proceeds to step S650.

_{In step S650, it is determined whether or not the time average value OCV Ave} of all cell voltages calculated in step S630 is less than a predetermined value. As a result, if the time average value OCV _Ave of all cell voltages is less than the predetermined value, the process proceeds to step S660, and if it is equal to or more than the predetermined value, the CC mode intermittent energization time t _{CC_DISC according} to the processing flow of FIG. 7 is terminated. As a result, the AC magnetic field is intermittently emitted from the primary coil L1 of the power transmission device 100 based on the estimation result of the battery state when the wireless power supply from the power transmission device 100 to the power reception device 200 is interrupted. Energizing time t _Determine whether to continue CC_DISC. The predetermined value used in the determination in step S650 is a voltage value for determining whether or not each cell of the battery 300 is in a state before reaching an overvoltage as a whole, for example, 4.2 V or the like. The value is set.

In step S660, the power transmission instruction unit 212 determines the current command value I _{CV *} and the frequency F _{CV *} when the battery 300 is intermittently charged in the CV mode. _{Here, for example, using the time average value OCV mAve} of the maximum cell voltage calculated in step S630, the _{current command value I CV *} is calculated by the following equation (5). In the formula (5), R _{cell represents the internal resistance value of the cell in which the time average value OCV mAve} of the maximum cell voltage is obtained among the internal resistance values of each cell included in the battery information acquired in step S620. .. Further, Vmax is a predetermined allowable maximum voltage value for each cell, and a value such as 4.2V is set.
I _{CV *} = (Vmax-OCV _mAve ) / R _cell ^ ・ ・ ・ (5)

On the other hand, the frequency F _{CV *} is set by, for example, a value stored in advance. The value of this frequency F _{CV *} may be the same as or different from the _{frequency F CV} determined in step S460 of FIG.

_{After determining the current command value I CV *} and the frequency F _{CV *} at the time of intermittent energization in the CV mode as described above, in step S670, the power transmission instruction unit 212 gives an instruction to start power transmission to the power transmission device 100. Here, the current command value I _{CV *} and the frequency F _{CV *} determined in step S660 are transmitted to the power transmission device 100 using the communication unit 220 to instruct the power transmission device 100 to start power transmission. When this power transmission start instruction is received by the communication unit 120 in the power transmission device 100, the power transmission device 100 causes a current to flow through the primary coil L1 according to the _{specified current command value I CV *} and frequency F _{CV * to generate an alternating magnetic field.} .. As a result, the wireless power supply from the power transmitting device 100 to the power receiving device 200 is restarted, and the energizing time t _{ON *} is started in _{the CV mode intermittent energizing time t CV_DISC.}

In step S680, in the power receiving device 200, the power conversion unit 250 and the constant current conversion unit 260 are driven according to the alternating current i that receives the alternating magnetic field emitted from the primary coil L1 and flows through the resonance circuit including the secondary coil L2. Perform control processing. Here, similarly to step S80 of FIG. 4, step S290 of FIG. 5, and step S480 of FIG. 6, the drive instruction unit 213 of the power receiving control unit 210, the drive signal generation unit 243 of the drive control unit 240, and the gate drive circuit 244 In, the drive control of the power conversion unit 250 and the constant current conversion unit 260 according to the alternating current received from the power transmission device 100 is performed. As a result, the battery 300 is charged in the constant voltage (CV) mode.

In step S690, it is determined whether or not the _{energization time t ON *} has elapsed from that time, based on the time when the power transmission start instruction is given in step S670 and the wireless power supply is restarted. The energization time t _{ON *} is set in advance according to the number of times the battery information is output and the output cycle, as in the case of the energization time t _{ON in the CC mode.} As a result, _{if it is determined that the energization time t ON *} has not yet elapsed, the process returns to step S680 to continue charging the battery 300, and if it is determined that the energization time t ON * has not elapsed, the process returns to step S610.

According to the first embodiment of the present invention described above, the following effects are exhibited.

(1) The power receiving device 200 receives an alternating magnetic field emitted from the primary coil L1 of the power transmitting device 100 installed on the ground side and wirelessly supplies power. The power receiving device 200 includes a secondary coil L2, a resonance coil Lx and a resonance capacitor Cx, which are resonance elements that are connected to the secondary coil L2 and form a resonance circuit having a predetermined resonance frequency together with the secondary coil L2. When the coil L2 receives an AC magnetic field, the AC current i flowing in the resonance circuit is converted into a DC current, and the power conversion unit 250 that charges the battery 300 using this DC current and a power transmission instruction that instructs the operation of the power transmission device 100. The unit 212 includes a battery state estimation unit 211 that acquires battery information regarding the state of the battery 300 and estimates the battery state indicating the state of the battery 300 based on the acquired battery information. The power transmission instruction unit 212 instructs the power transmission device 100 to intermittently emit an alternating magnetic field from the primary coil L1 (steps S220, S280, S610, S670), and the battery state estimation unit 211 interrupts the power transmission device 100. The battery state is estimated based on the battery information acquired while the power is being turned on (steps S240, S340, S630). Since this is done, the state of the battery 300 can be correctly estimated during wireless power supply.

(2) The power receiving device 200 has a constant current (CC) mode for charging the battery 300 while keeping the magnitude of the current flowing through the primary coil L1 constant. In the constant current (CC) mode, the power transmission instruction unit 212 determines the timing at which the battery state estimation unit 211 estimates the battery state before the start of charging the battery 300 (step S40), and according to the determined timing (step S70). : Yes) Instruct the power transmission device to perform intermittent energization (step S90). Since this is done, the battery state can be estimated at an appropriate timing in the CC mode.

(3) In the constant current (CC) mode, the transmission indicator 212 sends a current through the primary coil L1 at _{a predetermined transmission frequency F CC corresponding to the resonance frequency of the resonance circuit including the secondary coil L2 to generate an alternating magnetic field.} The power transmission device 100 is instructed to release the current (step S50). Further, before interrupting the alternating magnetic field during intermittent energization, the power transmission device 100 is instructed to change the _{transmission frequency F CC (step S210).} Since this is done, the efficiency of wireless power supply from the power transmission device 100 to the power receiving device 200 is lowered, the power received by the power receiving device 200 is reduced in advance, and the counter electromotive force generated in the power receiving device 200 when the power transmission is stopped. It is possible to prevent the power receiving device 200 from being destroyed.

(4) The power receiving device 200 further includes a drive control unit 240 that drives and controls the power conversion unit 250. In the constant current (CC) mode, the drive control unit 240 drives the power conversion unit 250 at a predetermined drive frequency corresponding to the resonance frequency of the resonance circuit including the secondary coil L2, and cuts off the alternating magnetic field during intermittent energization. This drive frequency is changed (step S210). Since this is done, the efficiency of wireless power supply from the power transmission device 100 to the power receiving device 200 is lowered, the power received by the power receiving device 200 is reduced in advance, and the counter electromotive force generated in the power receiving device 200 when the power transmission is stopped. It is possible to prevent the power receiving device 200 from being destroyed.

(5) The power receiving device 200 has a constant voltage (CV) mode for charging the battery 300 by changing the magnitude of the current flowing through the primary coil L1 according to the battery state. In the constant voltage (CV) mode, the power transmission instruction unit 212 determines whether or not to start intermittent energization based on the battery state estimated by the battery state estimation unit 211 while charging the battery 300, and determines that the start is started. In the case (step S440: Yes), the power transmission device 100 is instructed to perform intermittent energization (step S510). Since this is done, the battery state can be estimated at an appropriate timing in the CV mode.

(6) Whether or not the power transmission instruction unit 212 continues the intermittent power supply based on the battery state estimated by the battery state estimation unit 211 when the power transmission device 100 is performing intermittent power transmission in the constant voltage (CV) mode. If it is determined whether or not to continue (step S650: Yes), the power transmission device 100 is instructed to perform intermittent energization (step S670). Since this is done, intermittent energization in the CV mode can be continuously performed until an appropriate time point according to the battery state.

(7) In the constant voltage (CV) mode, the transmission indicator 212 sends a current through the primary coil L1 at a _{predetermined transmission frequency F CV different from the resonance frequency of the resonance circuit including the secondary coil L2 to generate an alternating magnetic field.} It is also possible to instruct the power transmission device 100 to emit (steps S460, S470). By doing so, it is possible to prevent an excessive charging current from flowing to the battery 300 in the CV mode, and to improve safety.

(8) The power receiving device 200 further includes a constant current conversion unit 260 that constantizes the direct current output from the power conversion unit 250, and the battery 300 uses the direct current converted to the constant current by the constant current conversion unit 260. To charge. Since this is done, the battery 300 can be charged efficiently.

-Second embodiment-
FIG. 8 is a diagram showing a configuration of a wireless power supply system 1A according to a second embodiment of the present invention. The wireless power supply system 1A shown in FIG. 8 is used for wireless power supply to a vehicle such as an electric vehicle, and is a power transmission device 100 installed on the ground side near the vehicle and a power receiving device mounted on the vehicle side, respectively. It has 200A, a battery 300, a load 400, and a battery monitoring device 500. Since the power transmission device 100, the battery 300, the load 400, and the battery monitoring device 500 are the same as those of the wireless power supply system 1 described in the first embodiment, the power receiving device 200A will be described below.

The power receiving device 200A is the same as the power receiving device 200 in the wireless power supply system 1 described in the first embodiment, except that the drive control unit 240A is provided instead of the drive control unit 240 and the AC current detection unit 230 is further provided. is there.

The alternating current detection unit 230 detects the alternating current flowing in the resonant circuit including the secondary coil L2 when the secondary coil L2 receives the alternating magnetic field emitted from the primary coil L1. Then, an AC voltage whose frequency and amplitude change according to the detected AC current is generated and output to the drive control unit 240A. The drive control unit 240A can acquire the frequency and magnitude of the AC current flowing through the resonance circuit based on the AC voltage input from the AC current detection unit 230. The drive control unit 240A changes the timing of the switching operation of each switching element based on the AC current flowing through the resonant circuit detected by the AC current detection unit 230.

FIG. 9 is a diagram showing a configuration example of the power receiving device 200A according to the second embodiment of the present invention. As shown in FIG. 9, the AC current detection unit 230 is configured by using, for example, a transformer Tr. Further, the drive control unit 240A further includes a voltage acquisition unit 241 in addition to the drive signal generation unit 243 and the gate drive circuit 244 described in the first embodiment.

When the magnetic flux generated by the AC magnetic field emitted from the primary coil L1 is linked with the secondary coil L2, an electromotive force is generated in the secondary coil L2, and an AC current i flows in the resonance circuit including the secondary coil L2. When this AC current i flows through the primary coil of the transformer Tr, an AC voltage Vg whose frequency and amplitude change according to the AC current i is generated at both ends of the secondary coil of the transformer Tr. As a result, the AC current detection unit 230 can detect the AC current i. If the AC current i flowing in the resonance circuit can be detected, the AC current detection unit 230 may be configured by using something other than the transformer Tr.

The voltage acquisition unit 241 acquires the AC voltage Vg output from the AC current detection unit 230 (transformer Tr) and outputs it to the drive signal generation unit 243. The drive signal generation unit 243 adjusts the phase of the basic drive signal Sr input from the drive instruction unit 213 of the power receiving control unit 210 based on the AC voltage Vg input from the voltage acquisition unit 241 to adjust the phase of the basic drive signal Sr, and the charge drive signal Sc. To generate. Then, the generated charge drive signal Sc is output to the gate drive circuit 244. As a result, in the power conversion unit 250, the phase of the alternating current i flowing in the resonance circuit including the secondary coil L2 is adjusted.

According to the second embodiment of the present invention described above, in addition to the effects of (1) to (8) described in the first embodiment, the effects of (9) and (10) below are further added. Play.

(9) The power receiving device 200A further includes an alternating current detecting unit 230 that detects the alternating current i flowing in the resonance circuit including the secondary coil L2. The power conversion unit 250 adjusts the phase of the AC current i based on the detection result of the AC current i by the AC current detection unit 230. Since this is done, the phase can be appropriately adjusted according to the state of the alternating current i.

(10) The AC current detection unit 230 detects the AC current i by generating an AC voltage Vg whose frequency and amplitude change according to the AC current i. Since this is done, the alternating current i can be easily detected.

In each of the above-described embodiments, the components of the drive control units 240 and 240A and the components of the power reception control unit 210 may be realized by software executed by a microcomputer or the like. , FPGA (Field-Programmable Gate Array) or the like. Further, these may be mixed and used.

In each of the above embodiments, the wireless power supply systems 1 and 1A used for wireless power supply to a vehicle such as an electric vehicle have been described. The invention may be applied.

The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Moreover, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1,1A wireless power supply system 100 power transmission device 110 power transmission control unit 120 communication unit 130 AC power supply 140 power conversion unit 200, 200A power reception device 210 power reception control unit 211 battery state estimation unit 212 power transmission instruction unit 213 drive instruction unit 220 communication unit 230 AC Current detection unit 240, 240A Drive control unit 241 Voltage acquisition unit 243 Drive signal generation unit 244 Gate drive circuit 250 Power conversion unit 260 Constant current conversion unit 270 Voltage meter 300 Battery 400 Load 500 Battery monitoring device L1 Primary coil L2 Secondary coil Lx Resonant coil Cx Resonant capacitor Tr transformer Q1, Q2, Q3, Q4, X1, X2 MOS transistor

Claims (10)

A power receiving device that receives an alternating magnetic field emitted from the primary coil of a power transmitting device installed on the ground side and is wirelessly fed.
With the secondary coil
A resonance element connected to the secondary coil and forming a resonance circuit having a predetermined resonance frequency together with the secondary coil.
A power conversion unit that converts the alternating current flowing in the resonance circuit into a direct current when the secondary coil receives the alternating current and charges the battery using the direct current.
A power transmission instruction unit that instructs the operation of the power transmission device, and
It is provided with a battery state estimation unit that acquires battery information regarding the state of the battery and estimates the battery state indicating the state of the battery based on the acquired battery information.
The power transmission instruction unit instructs the power transmission device to intermittently energize the alternating magnetic field to intermittently emit the AC magnetic field from the primary coil.
The battery state estimation unit is a power receiving device that estimates the battery state based on the battery information acquired when the power transmission device is performing the intermittent energization. In the power receiving device according to claim 1,
It has a constant current mode for charging the battery with the magnitude of the current flowing through the primary coil constant.
In the constant current mode, the power transmission instruction unit determines the timing at which the battery state estimation unit estimates the battery state before the start of charging of the battery, and the intermittent energization is performed by the power transmission device according to the determined timing. Power receiving device to instruct. In the power receiving device according to claim 2,
In the constant current mode, the power transmission instruction unit instructs the power transmission device to pass a current through the primary coil at a predetermined transmission frequency corresponding to the resonance frequency to emit the alternating magnetic field.
A power receiving device that instructs the power transmission device to change the transmission frequency before shutting off the alternating magnetic field during the intermittent energization. In the power receiving device according to claim 2,
A drive control unit that drives and controls the power conversion unit is further provided.
In the constant current mode, the drive control unit drives the power conversion unit at a predetermined drive frequency corresponding to the resonance frequency.
A power receiving device that changes the drive frequency before shutting off the alternating magnetic field during the intermittent energization. In the power receiving device according to claim 1,
It has a constant voltage mode for charging the battery by changing the magnitude of the current flowing through the primary coil according to the battery state.
In the constant voltage mode, the power transmission instruction unit determines whether or not to start the intermittent energization based on the battery state estimated by the battery state estimation unit while charging the battery, and determines that the start is started. A power receiving device that instructs the power transmission device to perform the intermittent energization in the case of a case. In the power receiving device according to claim 5,
In the constant voltage mode, the power transmission instruction unit determines whether or not to continue the intermittent energization based on the battery state estimated by the battery state estimation unit when the power transmission device is performing the intermittent energization. A power receiving device that instructs the power transmission device to perform the intermittent energization when it is determined and it is determined to continue. In the power receiving device according to claim 5,
In the constant voltage mode, the power transmission instruction unit instructs the power transmission device to emit an alternating magnetic field by passing a current through the primary coil at a predetermined transmission frequency different from the resonance frequency. In the power receiving device according to any one of claims 1 to 7.
A constant current conversion unit for converting the direct current output from the power conversion unit to a constant current is further provided.
A power receiving device that charges the battery using the direct current converted to a constant current by the constant current conversion unit. In the power receiving device according to any one of claims 1 to 7.
Further provided with an alternating current detecting unit for detecting the alternating current flowing in the resonant circuit,
The power conversion unit is a power receiving device that adjusts the phase of the AC current based on the detection result of the AC current by the AC current detection unit. In the power receiving device according to claim 9,
The AC current detection unit is a power receiving device that detects the AC current by generating an AC voltage whose frequency and amplitude change according to the AC current.

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