JP2019213265A - Non-contact power reception device - Google Patents

Abstract

To provide a non-contact power reception device capable of increasing output power factor of the inverter of a transmission apparatus easily in a wide coupling coefficient range.SOLUTION: A non-contact power reception device is configured to receive power, transmitted from the primary coil 101 of a transmission apparatus 100 by a secondary coil 201, in noncontact and to supply to a power storage device 300. The non-contact power reception device includes an LC resonance part R2 having a resonance part R2 secondary coil 201, a filter circuit F2 (LC filter) provided between the LC resonance part R2 and the power storage device 300, and a vehicle ECU500 for controlling the variable inductor 204 of the filter circuit F2. The vehicle ECU500 determines whether the combination coefficient of the primary coil 101 and the secondary coil 201 is large or small, and sets the inductance of the filter circuit F2 when the combination coefficient is larger than that when the combination coefficient is small.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a non-contact power receiving device, and more particularly, to a non-contact power receiving device that receives power transmitted from a primary coil of a power transmitting device in a non-contact manner by a secondary coil and supplies the power to a target device.

  There is known a non-contact power transmission system for transmitting power in a non-contact manner from a primary coil (hereinafter also referred to as “power transmission coil”) of a power transmission device to a secondary coil (hereinafter also referred to as “power reception coil”) of the power reception device. (See Patent Documents 1 to 6). For example, in the non-contact power transmission system described in JP-A-2006-195512 (Patent Document 6), the power transmission device includes an inverter that converts DC power into AC power and a control unit that controls the inverter. And the control part is suppressing that an excessively large electric current (overcurrent) flows into a power transmission coil by adjusting the output voltage of an inverter so that the current which flows into a power transmission coil may become below a threshold value.

JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A JP-A-2006-195512

  By the way, when the output power factor (ratio of active power to apparent power) of the inverter of the power transmission device decreases, the efficiency of the non-contact power transmission system (hereinafter also referred to as “system efficiency”) decreases. For this reason, the circuit constant in a non-contact electric power transmission system is preset so that the output power factor of the inverter of a power transmission apparatus may become high enough. The system efficiency corresponds to the energy efficiency of the entire contactless power transmission system (ratio of energy that can be recovered with respect to input energy).

  However, the coupling coefficient (hereinafter also simply referred to as “coupling coefficient”) between the primary coil (power transmission coil) and the secondary coil (power reception coil) changes under the condition that the circuit constant in the non-contact power transmission system is constant. Then, the output power factor of the inverter also changes. For example, when the circuit constant is set so that the output power factor of the inverter is high when the coupling coefficient is small, the phase of the inverter output voltage (hereinafter also referred to as “voltage phase”) is increased by increasing the coupling coefficient. ) And the phase of the output current of the inverter (hereinafter also referred to as “current phase”) increases (hereinafter also referred to as “output phase difference”), and the output power factor of the inverter decreases.

  In Patent Document 6, a decrease in the output power factor of the inverter (and hence a decrease in system efficiency) due to the change in the coupling coefficient as described above is not taken into consideration. Depending on the technique described in Patent Document 6, it is difficult to increase the output power factor of the inverter of the power transmission device in a wide coupling coefficient range.

  The present disclosure has been made to solve such a problem, and an object of the present disclosure is to provide a non-contact power receiving device that can easily increase the output power factor of the inverter of the power transmitting device in a wide coupling coefficient range. is there.

  The non-contact power receiving device (hereinafter, also simply referred to as “power receiving device”) in the present disclosure receives the power transmitted from the primary coil of the power transmitting device in a non-contact manner by the secondary coil and supplies the power to the target device. The apparatus includes an LC resonance unit, an LC filter, and a control unit. The LC resonance unit is configured by connecting a secondary coil and a capacitor in series or in parallel. The LC filter is provided between the LC resonance unit and the target device, and includes an inductance adjustment unit. The inductance adjusting unit is configured to be able to change the inductance of the LC filter. The control unit is configured to control the inductance adjusting unit.

  Then, the control unit determines whether the coupling coefficient between the primary coil and the secondary coil is large or small, and determines the inductance of the LC filter when the coupling coefficient is large, and the inductance of the LC filter when the coupling coefficient is small. Configured to be larger.

  In the non-contact power receiving apparatus, the inductance of the LC filter when the coupling coefficient is small is set in advance so that the output power factor of the inverter of the power transmission apparatus is sufficiently high in accordance with a predetermined reference coupling coefficient (for example, a small coupling coefficient). can do. Thereby, when the coupling coefficient is small, a sufficient output power factor of the inverter can be ensured.

  However, when the coupling coefficient increases, the coupling coefficient deviates from the reference coupling coefficient. For this reason, when the coupling coefficient is large and the inductance of the LC filter is maintained at the value when the coupling coefficient is small, the output power factor of the inverter decreases.

  Therefore, the control unit of the non-contact power receiving apparatus in the present disclosure makes the inductance of the LC filter when the coupling coefficient is large larger than the inductance of the LC filter when the coupling coefficient is small. Even when the coupling coefficient increases or the inductance of the LC filter increases, the output phase difference of the inverter of the power transmission device (and thus the output power factor of the inverter) changes. However, since the direction of change is reversed between the two, by increasing the inductance of the LC filter, it is possible to cancel (cancel) the fluctuation of the output phase difference of the inverter accompanying the increase of the coupling coefficient. For this reason, according to the said non-contact power receiving apparatus, it becomes easy to make the output power factor of the inverter of a power transmission apparatus high in a wide coupling coefficient range.

  The controller of the non-contact power receiving apparatus may determine whether the coupling coefficient is large or small based on a signal from the power transmitting apparatus. The power transmission device may generate a signal indicating whether the coupling coefficient is large or small based on the output current of the inverter. For example, if circuit constants (such as the inductance of the LC filter in the power receiving device) are set according to a small coupling coefficient, the output current of the inverter becomes excessively large due to impedance mismatch when the coupling coefficient is large. If the circuit constant is set in accordance with a large coupling coefficient, the output current of the inverter becomes excessively large when the coupling coefficient is small. By detecting such an overcurrent, the magnitude of the coupling coefficient can be easily detected.

  The non-contact power receiving apparatus may further include a distance measuring sensor that detects a distance between the primary coil and the secondary coil (hereinafter also referred to as “coil distance”). And said control part may judge whether a coupling coefficient is large or small based on the detection value of a ranging sensor.

  In the non-contact power receiving apparatus, the inductance adjustment unit may include a variable inductor. The inductance adjusting unit includes an inductor (for example, a coil) and a switching element (hereinafter also referred to as “L switch”) connected in parallel to the inductor as elements connected in series to the secondary coil. The inductance of the LC filter may be changeable depending on the state of the L switch (ON / OFF).

  The non-contact power receiving device of the present disclosure having the above configuration can construct a non-contact power transmission system together with the power transmission device. In such a non-contact power transmission system, if the output current of the inverter of the power transmission device becomes a predetermined value or higher during power transmission under the condition that the inductance of the LC filter of the power reception device is the first value, May be stopped and the inductance of the LC filter of the power receiving apparatus may be set to a second value different from the first value, and then power transmission may be resumed.

  According to the present disclosure, it is possible to provide a non-contact power receiving device that easily increases the output power factor of the inverter of the power transmitting device in a wide coupling coefficient range.

1 is an overall configuration diagram of a power transmission system to which a contactless power receiving device according to an embodiment of the present disclosure is applied. FIG. 2 is a diagram illustrating a configuration for performing non-contact power transmission between a charging facility and a vehicle in the power transmission system illustrated in FIG. 1. It is the figure which showed an example of the circuit structure of the inverter shown in FIG. It is a figure which shows the switching waveform of the inverter shown in FIG. 2, and each waveform of output voltage Vo and output current Iinv. 2 is a flowchart showing a charging control processing procedure executed by a vehicle control device in the power transmission system shown in FIG. 1. 2 is a flowchart showing a power transmission control processing procedure executed by a control device for a charging facility in the power transmission system shown in FIG. 1. It is a flowchart which shows the process sequence of the duty control shown in FIG. Inductive control of a power receiving filter executed by a non-contact power receiving device according to an embodiment of the present disclosure, induction of the power receiving filter in each of a region with a small coupling coefficient (region A) and a region with a large coupling coefficient (region B) It is a figure which shows sex reactance. In the power transmission system shown in FIG. 2, it is a figure which shows the output power factor of an inverter when the inductance of LC filter of a receiving device is made into a different value (L _L , L _H ) in the situation where a coupling coefficient is large. In the power transmission system shown in FIG. 2, it is a figure which shows the output current of an inverter when the inductance of LC filter of a power receiving apparatus is made into a different value (L _L , L _H ) in the situation where a coupling coefficient is large. FIG. 3 is a diagram illustrating system efficiency when the inductance of the LC filter of the power receiving apparatus is set to different values (L _L , L _H ) in a state where the coupling coefficient is large in the power transmission system illustrated in FIG. 2. It is a figure which shows the modification of the circuit structure of an electric power transmission system. It is a figure which shows the 1st modification of an inductance adjustment part. It is a figure which shows the 2nd modification of an inductance adjustment part. It is a figure which shows the 3rd modification of an inductance adjustment part.

  Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals and description thereof will not be repeated.

  Arrows F, B, U, and D in the drawings used below indicate directions relative to the vehicle, arrow F is “forward”, arrow B is “rear”, arrow U is “up”, arrow D indicates “below”. Hereinafter, the electronic control unit is referred to as “ECU (Electronic Control Unit)”.

  FIG. 1 is an overall configuration diagram of a power transmission system to which a contactless power receiving device according to an embodiment of the present disclosure is applied. The power transmission system 10 includes a charging facility 1 (ground unit) and a vehicle 2.

  The charging facility 1 includes a power transmission unit 100 and an AC power source 700 that supplies power to the power transmission unit 100. The power transmission unit 100 is installed on the ground F10 (for example, the floor of a parking lot). An example of the AC power supply 700 is a household power supply (for example, an AC power supply having a voltage of 200 V and a frequency of 50 Hz).

  The vehicle 2 includes a power reception unit 200, a power storage device 300 that is charged by the power received by the power reception unit 200, and a vehicle ECU 500 that controls the power received by the power reception unit 200. The power receiving unit 200 is provided on the lower surface (road surface side) of the power storage device 300 installed on the bottom surface F <b> 20 of the vehicle 2. In this embodiment, the power receiving unit 200 and the vehicle ECU 500 constitute an example of the “non-contact power receiving device” according to the present disclosure.

  The vehicle 2 may be an electric vehicle that can run using only the electric power stored in the power storage device 300, or uses both the electric power stored in the power storage device 300 and the output of an engine (not shown). The vehicle may be a hybrid vehicle capable of traveling.

  The power transmission unit 100 is configured to transmit power to the power reception unit 200 in a contactless manner through a magnetic field in a state where the vehicle 2 is aligned so that the power reception unit 200 of the vehicle 2 faces the power transmission unit 100. The power receiving unit 200 receives the power from the power transmitting unit 100 in a contactless manner.

  Hereinafter, the height from the wheel installation surface of the vehicle 2 (that is, the ground surface F10) to the power receiving coil of the power receiving unit 200 is referred to as “power receiving coil height ΔH”. In this embodiment, the receiving coil height ΔH of the vehicle 2 matches the minimum ground height of the vehicle 2. The distance between the power transmission coil provided on the surface of the power transmission unit 100 and the power reception coil provided on the surface of the power reception unit 200 (distance between coils ΔG) varies depending on the height of the power reception coil ΔH. As the power receiving coil height ΔH increases, the inter-coil distance ΔG also increases. Further, as the inter-coil distance ΔG increases, the coupling coefficient between the power transmission coil and the power reception coil tends to decrease. The power receiving coil height ΔH differs depending on the vehicle. In a general charging facility and vehicle, the coupling coefficient is 0.05 to 0.5.

  The power transmission coil and the power reception coil are a primary coil 101 and a secondary coil 201 shown in FIG. 2, respectively. FIG. 2 is a diagram illustrating a configuration for performing non-contact power transmission between the charging facility 1 and the vehicle 2. The power transmission unit 100 and the power reception unit 200 shown in FIG. 1 have a configuration as shown in FIG.

  Referring to FIG. 2, power transmission unit 100 obtains power for power transmission by performing predetermined power conversion processing on power received from AC power supply 700 and transmits the power for power transmission to power receiving unit 200 in a contactless manner. Configured. Then, the power storage device 300 (vehicle battery) is charged with the power received by the power reception unit 200 from the power transmission unit 100.

  The power transmission unit 100 includes a power conversion unit that performs the power conversion process, an LC resonance unit R1 that performs the contactless power transmission, and a power transmission ECU 150 that controls the power conversion unit and the like. The power conversion unit includes an AC / DC converter 130, an inverter 120, and a filter circuit F1. The LC resonance unit R1 is provided on the output side of the inverter 120, and is configured by connecting a primary coil 101 and a capacitor 102 in series.

  AC / DC converter 130 rectifies and transforms the power received from AC power supply 700 and outputs it to inverter 120. AC / DC converter 130 includes, for example, a rectifier circuit including a diode and a boost DC / DC converter including a switching element (for example, a power semiconductor switching element) that is chopper-controlled by power transmission ECU 150. AC / DC converter 130 boosts the power received from AC power supply 700 to 400 V, for example, and outputs DC power of voltage 400 V to inverter 120.

  The inverter 120 is configured to convert input power (more specifically, DC power) from the AC / DC converter 130 into AC power having a predetermined magnitude and frequency and output the AC power to the LC resonance unit R1. The output power of the inverter 120 is supplied to the LC resonance unit R1 through the filter circuit F1. In this embodiment, inverter 120 is a voltage source inverter (for example, a single-phase full bridge circuit shown in FIG. 3 described later). Inverter 120 is configured to be able to change the frequency of output power (hereinafter also simply referred to as “output frequency”) within a predetermined frequency range. Each switching element constituting inverter 120 is controlled in accordance with a drive signal from power transmission ECU 150.

  The output frequency of the inverter 120 changes according to the switching frequency (hereinafter also referred to as “drive frequency”) indicated by the drive signal. In this embodiment, the drive frequency of the inverter 120 matches the output frequency of the inverter 120 and eventually the power transmission frequency (frequency of transmitted power).

  Although details will be described later, the duty of the output voltage of inverter 120 is also controlled in accordance with a drive signal from power transmission ECU 150. Then, the magnitude of the output power of the inverter 120 changes according to the duty of the output voltage of the inverter 120. The duty of the output voltage of the inverter 120 is defined as the ratio of the positive (or negative) voltage output time to the cycle of the output voltage waveform (rectangular wave) (see FIG. 4 described later).

  The filter circuit F1 includes a capacitor 103 and a coil 104. The capacitor 103 is connected in parallel to the LC resonance unit R1, and the coil 104 is connected in series to the LC resonance unit R1. The capacitor 103 and the coil 104 form an LC filter that functions as a low-pass filter. This LC filter reduces electromagnetic noise.

  The LC resonance unit R1 transmits power to the LC resonance unit R2 of the power receiving unit 200 in a non-contact manner through a magnetic field generated around the primary coil 101. The LC resonance unit R1 is a series resonance circuit. The Q value of the LC resonance part R1 is preferably 100 or more.

  The power transmission ECU 150 includes an arithmetic device, a storage device, an input / output port, a communication port (all not shown), and the like. The arithmetic unit is configured by a microprocessor including, for example, a CPU (Central Processing Unit). The storage device includes a RAM (Random Access Memory) that temporarily stores data, and a storage (ROM (Read Only Memory), rewritable nonvolatile memory, and the like) that stores programs and the like. Various controls are executed by the arithmetic device executing the program stored in the storage device. For example, power transmission ECU 150 controls switching elements included in inverter 120 and AC / DC converter 130 to adjust transmitted power. The various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  The power transmission unit 100 further includes a voltage sensor 181 and current sensors 182 to 184. Voltage sensor 181 detects the input voltage of inverter 120 and outputs the detected value to power transmission ECU 150. Current sensor 182 detects an input current of inverter 120 and outputs the detected value to power transmission ECU 150. Current sensor 183 detects the output current of inverter 120 and outputs the detected value to power transmission ECU 150. Current sensor 184 detects the output current of filter circuit F1 (that is, the current processed by filter circuit F1), and outputs the detected value to power transmission ECU 150. The power transmission unit 100 may further include a temperature sensor (not shown) for detecting an abnormality.

  In this embodiment, the input voltage of inverter 120 and the output voltage of AC / DC converter 130 match. Further, the input current of the inverter 120 and the output current of the AC / DC converter 130 also coincide. Further, the output current of the filter circuit F1 coincides with the current flowing through the LC resonance unit R1 (primary coil 101 and the like).

  The power transmission unit 100 further includes a communication unit 160. The communication unit 160 is a communication interface for performing wireless communication with the vehicle 2. Communication unit 160 sends information from power transmission ECU 150 to vehicle 2, receives information from vehicle 2, and outputs the information to power transmission ECU 150.

  The power receiving unit 200 includes an LC resonance unit R2, a filter circuit F2, a rectifier circuit 206, and a smoothing capacitor 207.

  The LC resonance unit R2 is configured by connecting a secondary coil 201 and a capacitor 202 in series. Prior to the start of power transmission, the primary coil 101 and the secondary coil 201 are aligned so as to generate an interlinkage magnetic flux. Then, electric power is transmitted from the primary coil 101 to the secondary coil 201 by magnetic resonance. The secondary coil 201 receives power from the primary coil 101 of the power transmission unit 100 in a non-contact manner. The Q value of the LC resonance part R2 is preferably 100 or more. In this embodiment, as the LC resonating units R1 and R2, SS type (primary side: series, secondary side: series) resonance circuits are employed. However, the present invention is not limited to this, and the SP type (primary side: series). Secondary side: parallel), PP system (primary side: parallel, secondary side: parallel), etc. may be adopted.

  As described above, in this embodiment, the LC resonance unit R2 is a series resonance circuit. Hereinafter, the terminal on the secondary coil 201 side of the LC resonance unit R2 is referred to as “L terminal”, and the terminal on the capacitor 202 side of the LC resonance unit R2 is referred to as “C terminal”. Further, the electric wire connecting the L terminal of the LC resonance unit R2 and the terminal T5 of the rectifier circuit 206 is “power line PL1”, and the electric wire connecting the C terminal of the LC resonance unit R2 and the terminal T6 of the rectifier circuit 206 is “power line PL2”. Called.

  The filter circuit F <b> 2 includes capacitors 203 and 205 and a variable inductor 204. The capacitors 203 and 205 and the variable inductor 204 form an LC filter that functions as a low-pass filter (more specifically, a π-type LC filter). This LC filter reduces electromagnetic noise generated during power reception. The variable inductor 204 according to this embodiment corresponds to an example of an “inductance adjustment unit” according to the present disclosure.

  Variable inductor 204 is provided on power line PL2. That is, the variable inductor 204 is connected in series to the LC resonance unit R2. The variable inductor 204 includes, for example, a magnetic body (core) and an excitation winding, and is configured such that the inductance continuously changes according to a control signal (more specifically, the current of the excitation winding) from the power transmission ECU 150. Is done. The inductance of the variable inductor 204 can be adjusted to an arbitrary value by changing the magnetic permeability by passing a DC superimposed current through the exciting winding. Note that the present invention is not limited to this variable inductor, and any variable inductor can be selected from various known variable inductors.

  The capacitor 203 is connected in parallel to the LC resonance unit R2 on the LC resonance unit R2 side with respect to the variable inductor 204. One end of capacitor 203 is connected to power line PL1, and the other end of capacitor 203 is connected to power line PL2.

  The capacitor 205 is connected in parallel to the LC resonance unit R2 on the rectifier circuit 206 side of the variable inductor 204. One end of capacitor 205 is connected to power line PL1, and the other end of capacitor 205 is connected to power line PL2.

  The rectifier circuit 206 rectifies the AC power received by the secondary coil 201 and outputs the rectified power to the power storage device 300 side. The rectifier circuit 206 is configured by a diode bridge circuit composed of, for example, four diodes. A smoothing capacitor 207 is provided on the output side of the rectifier circuit 206. The capacitor 207 smoothes the DC power rectified by the rectifier circuit 206.

  The power receiving unit 200 further includes current sensors 283 and 284. Current sensor 284 detects a current flowing through LC resonance unit R2 (secondary coil 201 and the like) and outputs the detected value to power transmission ECU 150. Current sensor 283 detects the current of filter circuit F2 (more specifically, the current flowing between capacitor 203 and capacitor 205 in power line PL1), and outputs the detected value to power transmission ECU 150. The power receiving unit 200 may further include a temperature sensor (not shown) for detecting an abnormality.

  Output power of power receiving unit 200 (that is, DC power smoothed by capacitor 207) is supplied to power storage device 300 via charging relay 400. Charging relay 400 is ON / OFF controlled by vehicle ECU 500, and is turned on (conductive state) when power storage device 300 is charged by power receiving unit 200.

  The power storage device 300 is a rechargeable DC power source. Power storage device 300 includes, for example, a secondary battery (such as a lithium ion battery or a nickel metal hydride battery). The power storage device 300 stores the electric power supplied from the power receiving unit 200 and supplies the electric power to a vehicle drive device (running motor and its drive circuit) (not shown). The power storage device 300 according to this embodiment corresponds to an example of a “target device” according to the present disclosure.

  A monitoring unit 310 that monitors the state of the power storage device 300 is provided for the power storage device 300. Monitoring unit 310 includes various sensors that detect the state (temperature, current, voltage, etc.) of power storage device 300 and outputs the detection result to vehicle ECU 500. Vehicle ECU 500 is configured to acquire the state (SOC (State Of Charge), etc.) of power storage device 300 based on the output of monitoring unit 310. The SOC indicates the remaining amount of power storage. For example, the ratio of the current power storage amount to the fully charged power storage amount is expressed as 0 to 100%.

  Vehicle ECU 500 includes an arithmetic device, a storage device, an input / output port, a communication port (all not shown), and the like, and controls various devices in vehicle 2. The arithmetic device is constituted by a microprocessor including a CPU, for example. The storage device includes a RAM and a storage (such as a ROM or a rewritable nonvolatile memory) that stores programs and the like. In addition to the program, the storage device stores various types of information (for example, error information used in the process of FIG. 5 to be described later). Various controls are executed by the arithmetic device executing the program stored in the storage device. Vehicle ECU 500 executes, for example, travel control of vehicle 2 and charge control of power storage device 300. An ON / OFF signal or the like from the vehicle ECU 500 to the charging relay 400 is output from the output port. The various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit). The vehicle ECU 500 according to this embodiment corresponds to an example of a “control unit” according to the present disclosure. That is, vehicle ECU 500 is configured to control variable inductor 204 (inductance adjustment unit).

  The vehicle 2 further includes a communication unit 600. The communication unit 600 is a communication interface for performing wireless communication with the power transmission unit 100. By performing wireless communication between the communication unit 160 of the charging facility 1 and the communication unit 600 of the vehicle 2, information can be exchanged between the power transmission ECU 150 and the vehicle ECU 500.

  FIG. 3 is a diagram showing an example of a circuit configuration of inverter 120 shown in FIG. Referring to FIG. 3, inverter 120 includes a plurality of switching elements Q1-Q4 and a plurality of free-wheeling diodes D1-D4. Switching elements Q1-Q4 are constituted by, for example, a power semiconductor switching element (IGBT, bipolar transistor, MOSFET, GTO, or the like). The free-wheeling diodes D1 to D4 are connected in parallel (more specifically, in antiparallel) to the switching elements Q1 to Q4, respectively. An AC / DC converter 130 (FIG. 1) is connected to the DC-side input terminals T1 and T2, and a filter circuit F1 (FIG. 1) is connected to the AC-side output terminals T3 and T4.

  A DC voltage output from the AC / DC converter 130 is applied between the input terminals T1 and T2. In FIG. 3, V1 indicates the magnitude of this DC voltage. Switching elements Q1-Q4 are driven by a drive signal from power transmission ECU 150. Then, by the switching operation of the switching elements Q1 to Q4, the output voltage Vo is applied between the output terminals T3 and T4, and the output current Iinv flows (the direction indicated by the arrow in FIG. 3 is positive). FIG. 3 shows, as an example, a state in which the switching elements Q1 and Q4 are ON and the switching elements Q2 and Q3 are OFF, and the output voltage Vo in this case is almost V1 (positive value). .

  FIG. 4 is a diagram illustrating switching waveforms of the inverter 120 and waveforms of the output voltage Vo and the output current Iinv. Hereinafter, the operation of the inverter 120 will be described with reference to FIG. 4 together with FIG. 3 by taking one cycle from time t4 to time t8 as an example.

  At time t4, when the switching elements Q2 and Q4 are OFF and ON, respectively, and the switching element Q1 is switched from OFF to ON and the switching element Q3 is switched from ON to OFF, each switching element is in the state shown in FIG. The output voltage Vo of the inverter 120 rises from 0 to V1 (positive value).

  Thereafter, at times t5 to t8, the output voltage Vo also changes as the state of each switching element changes as follows. At time t5, when the switching element Q2 is switched from OFF to ON and the switching element Q4 is switched from ON to OFF, the output voltage Vo becomes zero. At time t6, when the switching element Q1 is switched from ON to OFF and the switching element Q3 is switched from OFF to ON, the output voltage Vo becomes −V1 (negative value). At time t7, when the switching element Q2 is switched from ON to OFF and the switching element Q4 is switched from OFF to ON, the output voltage Vo becomes 0 again.

  At time t8, one cycle after time t4, switching element Q1 is switched from OFF to ON, and switching element Q3 is switched from ON to OFF. As a result, each switching element is in the same state as at time t4, and the output voltage Vo rises from 0 to V1 (positive value).

  FIG. 4 shows a case where the duty of the output voltage Vo is 0.25. The ratio of the positive voltage output time (t4 to t5) in one cycle (t4 to t8) is 1/4 (= 0.25). Further, the ratio of the negative voltage output time (t6 to t7) in one cycle (t4 to t8) is also ¼ (= 0.25). As the duty of the output voltage Vo increases, the time during which the output voltage Vo is a positive voltage (V1) or a negative voltage (−V1) in one cycle becomes longer. For this reason, the output power of the inverter 120 increases as the duty of the output voltage Vo increases.

  By changing the switching timing of the switching elements Q1 and Q3 and the switching timing of the switching elements Q2 and Q4, the duty of the output voltage Vo can be changed. For example, when the switching timing of the switching elements Q2 and Q4 is advanced with respect to the state shown in FIG. 4, the duty of the output voltage Vo can be made smaller than 0.25 (the minimum value is 0), and the switching element Q2 , Q4 can be delayed to make the duty of the output voltage Vo larger than 0.25 (the maximum value is 0.5).

  By adjusting the duty of the output voltage Vo, the magnitude of the output power of the inverter 120, and hence the magnitude of the transmission power (the power supplied to the LC resonance unit R1) can be changed. Qualitatively, the output power of the inverter 120 can be increased by increasing the duty, and the output power of the inverter 120 can be decreased by decreasing the duty. Therefore, power transmission ECU 150 can adjust the duty of output voltage Vo to bring the magnitude of the output power of inverter 120 close to the target power (for example, a charging power command value described later).

  By the way, in the power transmission system 10, when the output power factor of the inverter 120 (the ratio of the effective power to the apparent power) decreases, the system efficiency decreases. When the output current of the inverter 120 is a sine wave, the output power factor of the inverter 120 is expressed as “λ”, and the output phase difference of the inverter 120 is expressed as “φ”, so that λ and φ are “λ = | cos φ |”. Satisfies the relational expression. The output phase difference φ is expressed with reference to the voltage phase. In other words, the output phase difference is a positive value when the current phase is shifted toward the retarded side with respect to the voltage phase, and the output level is shifted when the current phase is shifted toward the advanced side relative to the voltage phase. The phase difference is negative. For example, if the output phase difference is 0 ° (no phase difference), the output power factor of the inverter 120 is 1 (active power only). As the output phase difference increases, the output power factor of the inverter 120 tends to decrease (that is, the reactive power increases).

  In this embodiment, at the initial stage (for example, at the time of initialization in the process of FIG. 5 described later), when the coupling coefficient is small (for example, when the coupling coefficient is 0.05 to 0.3), the output of inverter 120 Circuit constants (such as the inductance of the variable inductor 204) are set so that the power factor becomes high. Thereby, when the coupling coefficient is small, the output power factor of the inverter 120 of the power transmission unit 100 is sufficiently high. However, if the circuit constant (such as the inductance of the variable inductor 204) is maintained at a value when the coupling coefficient is small when the coupling coefficient becomes large (for example, when the coupling coefficient becomes about 0.5), the inverter 120 The output power factor decreases.

Therefore, vehicle ECU 500 sets the inductance of variable inductor 204 when the coupling coefficient is large to be larger than the inductance of variable inductor 204 when the coupling coefficient is small. Hereinafter, the inductance of the variable inductor 204 may be referred to as “filter inductance L ₂₂ ” or simply “L ₂₂ ”. Filter inductance _{L 22} corresponds to the inductance of the filter circuit F2. Further, the value of L ₂₂ when the coupling coefficient is small may be referred to as “L _L ”, and the value of L ₂₂ when the coupling coefficient is large may be referred to as “L _H ”. L _L is obtained in advance by experiments or the like, and the output phase difference of the inverter 120 becomes small in the region where the coupling coefficient is small (for example, the region where the coupling coefficient is 0.05 or more and 0.30 or less). The value becomes higher). On the other hand, L _H is obtained by experiment or the like in advance, region coupling coefficient is large (e.g., coupling coefficient regions is 0.25 to 0.60) output phase of the inverter 120 is reduced in (thus, the output The power factor is increased). L _H is a value larger than L _L.

  Even when the coupling coefficient increases or the inductance of the variable inductor 204 increases, the output phase difference of the inverter 120 of the power transmission unit 100 (and thus the output power factor of the inverter) changes. However, since the direction of change is reversed between the two, increasing the inductance of the variable inductor 204 can cancel the fluctuation in the output phase difference of the inverter 120 due to an increase in the coupling coefficient. Thereby, it becomes easy to ensure a sufficient output power factor of the inverter 120 in a wide coupling coefficient range.

  Next, an example of a processing procedure in the case where the inductance control as described above is incorporated in the non-contact charging control and the power storage device 300 of the vehicle 2 is charged by the charging facility 1 will be described.

  First, the driver stops the vehicle 2 in the charging space of the charging facility 1. Then, after establishing a communication connection (for example, connection to a wireless LAN) between the vehicle ECU 500 and the power transmission ECU 150 at the stop position of the vehicle 2, a power transmission request is sent from the vehicle ECU 500 to the power transmission ECU 150. The power transmission request may be transmitted according to a driver's instruction, or may be automatically transmitted when a predetermined condition is satisfied.

  When power transmission ECU 150 receives this power transmission request, charging information (information indicating the specifications of charging facility 1) and vehicle information (information indicating the specifications of vehicle 2) are collated between power transmission ECU 150 and vehicle ECU 500. It is determined whether or not the vehicle 2 can be charged by the charging facility 1 based on the result of this collation. More specifically, the vehicle information includes, for example, the vehicle type (or identification number) of the vehicle 2, the rated voltage of the power storage device 300, and the like. Further, the charging information includes, for example, power supplied to the charging facility 1 and a maximum output voltage. When the specification of the vehicle 2 corresponds to the specification of the charging facility 1, the power transmission ECU 150 and the vehicle ECU 500 determine that the vehicle 2 can be charged by the charging facility 1 (chargeable), and prepare for the power transmission preparation described below. move on. On the other hand, when the specifications of vehicle 2 do not correspond to the specifications of charging equipment 1 (for example, when the maximum output voltage of charging equipment 1 is too high or too low with respect to the rated voltage of power storage device 300), power transmission ECU 150 The vehicle ECU 500 determines that the vehicle 2 cannot be charged by the charging facility 1 (cannot be charged), and stops the charging process.

  When it is determined that charging is possible by the above collation, the power transmission ECU 150 starts preparation for power transmission. The power transmission preparation is a process for setting the power transmission system 10 in a state where power can be transmitted. For example, alignment between the power transmission unit 100 and the power reception unit 200 is performed as the power transmission preparation. When charging facility 1 includes a plurality of power transmission units, a process (so-called pairing) for specifying which power transmission unit is aligned may be performed as the power transmission preparation. . Various methods are known as alignment and pairing methods, and any method can be adopted.

  When the preparation for power transmission is completed, non-contact power transmission is performed between the power transmission ECU 150 of the charging facility 1 and the vehicle ECU 500 of the vehicle 2, and the power storage device 300 of the vehicle 2 is charged by the power supplied from the charging facility 1. Is done.

  FIG. 5 is a flowchart showing a charging control processing procedure executed by vehicle ECU 500 after the above-described collation and power transmission preparation are completed. The processes shown in this flowchart are steps S11 to S17, S21 to S23, S31 to S32 (hereinafter simply referred to as “S11” to “S17”, “S21” to “S23”, and “S31” to “S32”). including.

Referring to FIG. 5, vehicle ECU 500 initializes (S11). More specifically, vehicle ECU 500 controls variable inductor 204 to set filter inductance L ₂₂ to L _L (initial value). Further, vehicle ECU 500 initializes error information stored in the storage device. Initially, the error information indicates that no abnormality has occurred.

  Next, the vehicle ECU 500 turns on (closes) the charging relay 400 (S12). The following S13, S21, S14, S15, S22, and S16 (hereinafter may be referred to as “loop processing S13 to S16”) are before charging and during charging (except when an abnormality occurs). Repeatedly.

  In S13, vehicle ECU 500 determines whether an abnormality has occurred on the power receiving side. The vehicle ECU 500 has, for example, the voltage and current of each part of the power receiving unit 200 (the output voltage of the power receiving unit 200 detected by the monitoring unit 310, the current detected by the current sensors 283, 284, etc.) within a predetermined allowable range. Judge whether there is. When at least one of the voltage and current of each part of the power receiving unit 200 is not within the allowable range (for example, when an overvoltage and / or overcurrent occurs), it is determined that an abnormality has occurred on the power receiving side.

  Note that the method for determining the presence or absence of abnormality is arbitrary. For example, vehicle ECU 500 may determine that an abnormality has occurred on the power receiving side when the temperature of a predetermined portion of power receiving unit 200 or the temperature of power storage device 300 is excessively high.

If no abnormality has occurred on the power receiving side (NO in S13), the process proceeds to S21. In S21, the vehicle ECU500 determines whether or not it has received a _{L 22} change request (see step S83 in FIG. 7 to be described later) from the power transmission unit 100.

The L ₂₂ change request is a signal indicating that the coupling coefficient is large. L ₂₂ change request, if the coupling coefficient is large, is transmitted from the power transmission unit 100 to the vehicle 2. Although details will be described later, the L ₂₂ change request is transmitted toward the vehicle 2 when it is detected in the power transmission unit 100 that the output current of the inverter 120 is excessively large. In vehicle 2, communication unit 600 receives the _L22 change request. Vehicle ECU 500 receives an L ₂₂ change request from communication unit 600.

When it is determined that it has received the L ₂₂ change request (YES in S21), the vehicle ECU500 is, the _{L 22} is changed from _{L L} to _L H (greater than _{L L)} in _S32, the _{L 22} A signal indicating that the change has been completed (hereinafter referred to as “L ₂₂ change completion notification”) is transmitted to the power transmission unit 100. Thereafter, the process proceeds to S14. On the other _hand, when it is determined that it has not received the _{L 22} change request (NO in S21), without the processing of S32 is executed, the process proceeds to S14.

  In S14, vehicle ECU 500 calculates charging power command value Ps (hereinafter sometimes simply referred to as “Ps”) based on the state of power storage device 300 detected by monitoring unit 310, for example, and the calculated value obtained. Is stored in a storage device. More specifically, vehicle ECU 500 decreases charge power command value Ps as the SOC of power storage device 300 approaches full charge (100%). Note that the SOC measurement method is arbitrary, and a method based on current value integration (Coulomb count), a method based on estimation of an open circuit voltage (OCV), or the like can be employed.

In S15, vehicle ECU 500, for example, based on the current and voltage of power storage device 300 detected by monitoring unit 310, power supplied from power reception unit 200 to power storage device 300 (hereinafter referred to as “actual charging power P _out ”, or Simply referred to as “P _out ”), and the obtained detection value is stored in a storage device.

In S <b> 22, vehicle ECU 500 controls communication unit 600 to send information to power transmission unit 100. Predetermined information (for example, Ps and P _out ) is transmitted from the communication unit 600 toward the power transmission unit 100. The information transmitted from the communication unit 600 is received by the communication unit 160 in the power transmission unit 100.

  In S16, vehicle ECU 500 determines whether or not charging is completed. For example, vehicle ECU 500 determines that charging is completed when a predetermined completion condition is satisfied. The completion condition is satisfied, for example, when the SOC of power storage device 300 becomes equal to or higher than a predetermined SOC value during charging. The predetermined SOC value may be automatically set by the vehicle ECU 500 or the like, or may be set by the user.

  In this embodiment, it is assumed that the above completion condition is satisfied when the SOC of power storage device 300 is fully charged (100%) during charging. However, the present invention is not limited to this, and the completion condition can be arbitrarily set. For example, the completion condition may be satisfied when the charging time (elapsed time from when charging is started) becomes longer than a predetermined value. Further, the completion condition may be satisfied when the user gives an instruction to stop charging during charging.

  If charging has not been completed (NO in S16), the process returns to S13. Loop processing S13 to S16 is repeatedly executed until it is determined that charging has been completed in S16 (YES in S16) or an abnormality has occurred in S13 (YES in S13).

  If YES is determined in any of S13 and S16, a charge stop process (S23 and S17) described below is performed. However, if it is determined YES in S13, after the process of S31, the charge stop process (S23 and S17) is forcibly performed without waiting for the completion of the charge. In S31, vehicle ECU 500 updates error information stored in the storage device. As a result, the fact that an abnormality has occurred and the content of the abnormality are written in the error information. By referring to the error information after stopping the charging, it is possible to know whether the charging has been normally completed and stopped, or whether the charging has been forcibly performed due to an abnormality during the charging.

  In S23, vehicle ECU 500 controls communication unit 600 to transmit information to power transmission unit 100. Predetermined information (for example, a power transmission stop request and error information) is transmitted from the communication unit 600 to the power transmission unit 100. The information transmitted from the communication unit 600 is received by the communication unit 160 in the power transmission unit 100.

  Subsequently, the vehicle ECU 500 turns off (opens) the charging relay 400 (S17). As a result, the power supply path to power storage device 300 is interrupted, and power supply to power storage device 300 (and thus charging of power storage device 300) is not performed. With this S17, the processing of FIG. 5 ends.

  FIG. 6 is a flowchart showing a power transmission control processing procedure executed by power transmission ECU 150 after the above-described collation and power transmission preparation are completed. The process shown in this flowchart includes steps S51 to S58, S61, and S62 (hereinafter simply referred to as “S51” to “S58”, “S61”, and “S62”).

  Referring to FIG. 6, power transmission ECU 150 sets 0 (initial value) to ΔPs used in S55 and S56 described later and S76 in FIG. 7 (S51). Subsequently, power transmission ECU 150 sets a predetermined minimum value as drive frequency f in the drive signal of inverter 120 (S52). In this embodiment, the minimum value of the drive frequency f is 81.4 kHz.

  Next, the transmission power is adjusted by controlling the duty of the output voltage of the inverter 120 (S61). FIG. 7 is a flowchart showing the processing procedure of this duty control. The processes shown in this flowchart are steps S71 to S78, S81 to S84, S91, and S92 (hereinafter simply referred to as “S71” to “S78”, “S81” to “S84”, “S91”, and “S92”). including.

  Referring to FIG. 7, power transmission ECU 150 sets a predetermined minimum value as duty D (hereinafter also simply referred to as “duty D”) of the output voltage in the drive signal of inverter 120 (S71). In this embodiment, the minimum value of the duty D is set to zero.

  Next, the power transmission ECU 150 determines whether or not a power transmission stop request (S23 in FIG. 5) has been received from the vehicle 2 (S72). If it is determined that a power transmission stop request has not been received (NO in S72), power transmission ECU 150 determines whether an abnormality has occurred on the power transmission side (S73). The determination method of the presence or absence of abnormality in S73 is arbitrary. For example, power transmission ECU 150 may determine that an abnormality has occurred on the power transmission side when the temperature of a predetermined portion of power transmission unit 100 is excessively high.

  If there is no abnormality on the power transmission side (NO in S73), power transmission ECU 150 drives inverter 120 and AC / DC converter 130 to execute power transmission from primary coil 101 to secondary coil 201. (S74). AC / DC converter 130 is controlled such that the magnitude of the input voltage (DC voltage) of inverter 120 is constant, for example. For the drive signal of the inverter 120, the drive frequency f and the duty D of the output voltage are set to the values set in S52 or S53 in FIG. 6 and S71 or S77 in FIG. As the drive frequency f, the minimum value set in S52 in FIG. 6 is used at first, but when the process in S53 in FIG. 6 described later is performed, the value set in S53 is used. Further, the duty D of the output voltage initially becomes the minimum value set in S71, but increases by a predetermined amount every time the process of S77 described later is executed.

  In S <b> 75, power transmission ECU 150 determines whether the current of each part of power transmission unit 100 (for example, the current detected by current sensors 182 to 184) is within a predetermined allowable range. If at least one of the currents in each part of the power transmission unit 100 is not within the allowable range (for example, if an overcurrent has occurred), NO is determined in S75, and all the currents in each part of the power transmission unit 100 are within the allowable range. If YES, YES is determined in S75.

  When it is determined NO in S75, it is determined whether or not the output current of the inverter 120 exceeds the allowable range (S81). More specifically, power transmission ECU 150 determines whether or not the output current of inverter 120 detected by current sensor 183 is equal to or greater than a predetermined threshold value.

In this embodiment, the filter inductance L ₂₂ is initially set to a value (L _L ) that matches a small coupling coefficient (reference coupling coefficient). For this reason, when the coupling coefficient is large (for example, when the inter-coil distance ΔG is small), the difference between the coupling coefficient and the reference coupling coefficient becomes large, and the output current of the inverter 120 becomes excessively large due to impedance mismatch. By monitoring the presence or absence of such an overcurrent, it can be easily determined whether the coupling coefficient is large or small.

A determination of YES in S81 (that the output current of the inverter 120 is equal to or greater than the threshold value) means that the coupling coefficient is large. In this case, since it is considered that an overcurrent has occurred due to a large coupling coefficient (that is, the coupling coefficient is greatly deviated from the reference coupling coefficient), L ₂₂ is changed in accordance with the large coupling coefficient. As a result, no overcurrent occurs.

If YES is determined in S81, in S82, the power transmission ECU 150 stops the power transmission by stopping the inverter 120 and the AC / DC converter 130 (non-driving state). Subsequently, in S83, the power transmission ECU150 _sends a signal requesting a change of _{L 22} a _{(L 22} change request) to the vehicle 2. If the coupling coefficient is large in the vehicle 2 only (YES at S81) _{L 22} change request is transmitted. For this reason, for the vehicle ECU 500, the L ₂₂ change request is a signal requesting the change of L ₂₂ and also a signal indicating that the coupling coefficient is large.

When receiving the L ₂₂ change request, the vehicle ECU 500 changes the filter inductance L ₂₂ from L _L to L _H and transmits an L ₂₂ change completion notification to the power transmission unit 100 (see S32 in FIG. 5). By L ₂₂ is changed in the power receiving unit 200, L ₂₂ is the value matching the large coupling coefficient (L _H), overcurrent as described above will not occur. Incidentally, since the case where the output current of the inverter 120 again after sending L ₂₂ change request becomes excessively large (YES at S81) in S83, considered not normal, it is determined that an abnormality has occurred Then, a power transmission stop process (S91 and S92), which will be described later, may be performed.

After transmission of the L ₂₂ change request transmission ECU150 waits for _{L 22} change completion notification from the vehicle 2 _receives the _{L 22} change completion notification, in S84, by driving the inverter 120 and AC / DC converter 130, 1 The power transmission from the secondary coil 101 to the secondary coil 201 is resumed. Thereafter, the process returns to S72.

  On the other hand, determining NO in S81 means that an overcurrent has occurred due to a factor other than the coupling coefficient. If it is determined NO in S81, there is a high possibility that the drive frequency f is not matched, so the process is returned to the main routine (the process of FIG. 6), and duty control at the current drive frequency f is performed. finish. The process proceeds to S53 in FIG.

If all of the components of the current in the transmitting unit 100 is within the allowable range (YES in S75), the transmission ECU150 is whether the deviation between the charging power command value Ps and the actual charging power _{P out} is sufficiently small Judgment is made (S76).

  Charging power command value Ps is generated in vehicle ECU 500 (see S14 in FIG. 5) and transmitted from vehicle 2 to power transmission unit 100 (see S22 in FIG. 5). When ΔPs is 0 (initial value) (see S51 in FIG. 6), power transmission ECU 150 uses the value received from vehicle 2 as it is as charging power command value Ps in S76. On the other hand, when the process of S55 of FIG. 6 described later is performed, ΔPs becomes a value larger than 0, and charging power command value Ps is corrected by ΔPs. In this case, power transmission ECU 150 uses a value obtained by subtracting ΔPs from the value received from vehicle 2 as charging power command value Ps in S76.

The actual charging power P _out is generated in the vehicle ECU 500 (see S15 in FIG. 5) and transmitted from the vehicle 2 to the power transmission unit 100 (see S22 in FIG. 5). Transmission ECU150, in S76, using the values received from the vehicle 2 as it is as the actual charging power _{P out.}

In S76, by using the Ps and _{P out,} the calculated deviation between Ps and _{P out,} whether the deviation is sufficiently small or not. The deviation is a parameter indicating a deviation (degree of difference) between two values. As the deviation, a difference or a ratio can be adopted. The greater the difference (absolute value), the greater the deviation. Also, the closer the ratio is to 1, the smaller the deviation. In this embodiment, in S76, the difference between the Ps and _{P out (| Ps-P out} |) is a predetermined threshold Th1 (hereinafter, simply referred to as "Th1") or not less either, transmission ECU 150 determines.

When it is determined NO in S76 (when | Ps−P _out | is greater than Th1), power transmission ECU 150 sets duty D of the output voltage in the drive signal of inverter 120 by unit operation amount ΔD from the current value. Increase (S77). Subsequently, the power transmission ECU 150 determines whether the duty D is equal to or less than a predetermined threshold value Th2 (hereinafter also simply referred to as “Th2”) (S78). Th2 corresponds to the maximum value of the duty D. In this embodiment, Th2 (the maximum value of duty D) is set to 0.5. If duty D does not become larger than Th2 even after the process of S77 (YES in S78), the process returns to S72.

Also, if it is determined YES in S76, the process returns to S72. A determination of YES in S76 indicates that there is a duty D in which | Ps−P _out | is equal to or less than Th1 in a range (0.0 to 0.5) from the minimum value to the maximum value of the duty D. means. If the duty D so that the deviation between the Ps and P _out during the transmission is sufficiently small is adjusted, so that stable transmission is performed. If continued transmission under the same conditions after the adjustment of the duty D, and basically, the deviation between the Ps and P _out is kept small, it does not occur overcurrent. Therefore, if YES is determined in S76, a power transmission stop request is received from vehicle 2 (YES in S72), or it is determined that an abnormality has occurred in S73 (YES in S73). , S72 to S76 are repeatedly executed, and stable power transmission is continued.

Further, when NO is determined in S78 (duty D is larger than Th2), the range from the minimum value to the maximum value of duty D (0.0 to 0.5) becomes | Ps−P _This means that there is no duty D at which _out | becomes equal to or less than Th1. If NO is determined in S78, the process returns to the main routine (the process of FIG. 6), and the duty control at the current drive frequency f ends. The process proceeds to S53 in FIG.

  If YES is determined in any of S72 and S73, a power transmission stop process (S91 and S92) described below is performed.

  In S91, power transmission ECU 150 stops inverter 120 and AC / DC converter 130 in a stopped state (non-driving state) to stop power transmission. In S <b> 92, power transmission ECU 150 controls communication unit 160 to send information to vehicle 2. Predetermined information (for example, a power transmission stop notification indicating that power transmission stop has been completed) is transmitted from the communication unit 160 toward the vehicle 2. When power transmission stops due to the occurrence of an abnormality (YES in S73), an abnormality occurrence notification indicating that an abnormality has occurred may be transmitted from the communication unit 160 to the vehicle 2. The information transmitted from the communication unit 160 is received by the communication unit 600 in the vehicle 2. With this S92, not only the processing of FIG. 7 but also the processing of FIG. 6 (power transmission control by the power transmission ECU 150) ends.

  Referring to FIG. 6 again, if NO is determined in any of S78 and S81 in FIG. 7, the process proceeds to S53. In S53, power transmission ECU 150 increases drive frequency f in the drive signal of inverter 120 by unit operation amount Δf from the current value. Subsequently, the power transmission ECU 150 determines whether or not the drive frequency f is less than a predetermined threshold value Th3 (hereinafter also simply referred to as “Th3”) (S54). In this embodiment, Th3 (upper limit value of the driving frequency f) is 90.0 kHz. If drive frequency f does not become equal to or higher than Th3 even after the process of S53 (YES in S54), the above-described duty control (process of FIG. 7) is executed at the drive frequency f (S62).

When NO is determined in S54 (the drive frequency f is equal to or greater than Th3), the duty control (duty adjustment range: 0.0 to 0.5) is performed while changing the drive frequency f. This means that there is no drive frequency f at which | Ps−P _out | is equal to or less than Th1 in the adjustment range (81.4 kHz to 90.0 kHz) of the drive frequency f (see S76 in FIG. 7). If NO is determined in S54, the process proceeds to S55.

  In S55, power transmission ECU 150 decreases charge power command value Ps by increasing ΔPs indicating a correction amount (more specifically, a decrease amount) of charge power command value Ps by a unit operation amount from the current value. . ΔPs is used in the processing of FIG. In S76 of FIG. 7, the charging power command value Ps received from the vehicle 2 is subtracted and corrected (Ps−ΔPs) by ΔPs. As ΔPs increases, the corrected Ps decreases. Each time the process of S55 is executed, ΔPs increases by the unit operation amount. The unit operation amount can be set arbitrarily.

  Subsequently, power transmission ECU 150 determines whether ΔPs is equal to or greater than a predetermined threshold value Th4 (hereinafter also simply referred to as “Th4”) (S56). If ΔPs does not become equal to or greater than Th4 even after the process of S55 (NO in S56), the process returns to S52. Then, the drive frequency f and the duty D are adjusted again for the charging power command value Ps that is decreased by the process of S55.

If YES is determined in S56 (ΔPs becomes equal to or greater than Th4), even if the charge power command value Ps is decreased within the adjustment range of ΔPs (0 to Th4), | Ps−P _out | becomes less than Th1. (See S76 in FIG. 7). If YES is determined in S56, power transmission stop processing (S57 and S58) is performed. S57 and S58 are processes according to S91 and S92 of FIG. 7 described above. That is, in S57, power transmission ECU 150 stops inverter 120 and AC / DC converter 130 in a stopped state (non-driving state) to stop power transmission. In S <b> 58, power transmission ECU 150 controls communication unit 160 to transmit information toward vehicle 2. With this S58, the processing of FIG. 6 (power transmission control by the power transmission ECU 150) ends.

As described above, vehicle ECU 500 according to this embodiment determines whether the coupling coefficient is large or small (S21 in FIG. 5), and determines the inductance (L _H ) of filter circuit F2 when the coupling coefficient is large. It is larger than the inductance (L _L ) of the filter circuit F2 when the coupling coefficient is small. When the coupling coefficient is large (YES in S21 in FIG. 5), the coupling coefficient is changed by changing the inductance (filter inductance L ₂₂ ) of the LC filter of the power receiving unit 200 from L _L to L _H (S32 in FIG. 5). Can offset the increase in the output phase difference of the inverter 120 due to the deviation from the reference coupling coefficient, and the output phase difference of the inverter 120 can be reduced. By performing such control, the output power factor of the inverter 120 of the power transmission unit 100 can be easily increased in a wide coupling coefficient range.

  In the power transmission system 10 according to this embodiment, the circuit constant is adjusted not in the configuration of the charging facility 1 but in the configuration of the vehicle 2 (more specifically, the variable inductor 204). In general, it is easier to change the configuration of a vehicle (change of the hardware configuration) than to the charging facility. Therefore, providing the method according to the above embodiment as a method of improving the output power factor of the inverter in the charging facility It is beneficial.

  By changing the inductance instead of the capacitance in the filter circuit F2, the output power factor of the inverter 120 can be improved while suppressing the change in the resonance frequency of the LC resonance unit R2. When the capacitance of the filter circuit F2 (for example, the capacitance of the capacitor 203 or 205) is changed, the resonance frequency of the LC resonance unit R2 changes. On the other hand, even if the inductance of the filter circuit F2 (for example, the inductance of the variable inductor 204) is changed, the resonance frequency of the LC resonance unit R2 hardly changes. In the above embodiment, the capacitance of the filter circuit F2 is constant (fixed value).

Further, either in the process of FIG. 5 to FIG. 7, the vehicle ECU500, based on the signal _{(L 22} change request) from the power transmission unit 100, small or coupling coefficient between the primary coil 101 and secondary coil 201 is greater Judging. That is, the vehicle ECU500 for a predetermined period (e.g., during charging) when receiving the _{L 22} change request from the power transmission unit 100 in determining the coupling coefficient is large in (YES at S21 in FIG. 5), the predetermined in a case where it does not receive the L ₂₂ change request from the power transmission unit 100 in the period (NO in S21 always in during 5), it is judged that the coupling coefficient is small. Further, the power transmitting unit 100 generates an _{L 22} change requests based on the output current of the inverter 120 is transmitted to the vehicle 2 (S81~S83 in Figure 7). More specifically, the L ₂₂ change request is transmitted from the power transmission unit 100 to the vehicle 2 when the output current of the inverter 120 becomes an overcurrent. By monitoring the presence or absence of such an overcurrent, the coupling coefficient can be easily detected. The fact that such overcurrent does not occur means that the coupling coefficient is small. When the coupling coefficient is small, the L ₂₂ change request is not transmitted from the power transmission unit 100 to the vehicle 2.

It is also conceivable that the coupling coefficient is calculated in real time from the detection values of various sensors and the L ₂₂ is precisely controlled according to the calculated coupling coefficient. However, it is difficult to calculate the coupling coefficient with high accuracy, and even if the coupling coefficient can be calculated with high accuracy, the control becomes complicated and processing delays are likely to occur.

In the process of FIG. 5 to FIG. 7, when the filter inductance L ₂₂ is the output current of the inverter 120 of the power transmission unit 100 exceeds a predetermined value during transmission in a condition which is a first value (L _L) (Fig. the YES) at 7 S81 of, by stopping the power transmission in progress (S82 in FIG. 7), after the different second value _{(L H)} has a filter inductance _{L 22} and the first value (Fig. 7 (S83 and S21, S32 in FIG. 5), power transmission is resumed (S84 in FIG. 7). According to such control can be performed appropriately changing the L _22.

  FIG. 8 shows power reception in each of a region with a small coupling coefficient (region A) and a region with a large coupling coefficient (region B) in the inductance control of the power receiving filter (filter circuit F2 of the power receiving unit 200) according to this embodiment. It is a figure which shows the inductive reactance of a filter. Hereinafter, the output angular frequency of the inverter 120 may be described as “ω”.

Referring to FIG. 8, in the inductance control according to this embodiment, in region A where the coupling coefficient is less than Kx, filter inductance L ₂₂ is L _L and inductive reactance of filter circuit F 2 is ωL _L. . Further, in the region B the coupling coefficient is equal to or greater than Kx, filter inductance _{L 22} is the _{L H,} the inductive reactance of the filter circuit F2 is .omega.L _H. L _H is larger than _{L L, ωL H} is greater than .omega.L _L. According to the inductance control according to this embodiment, when the coupling coefficient is large (region B), the inductive reactance of the filter circuit F2 (LC filter of the power receiving unit 200) is smaller than when the coupling coefficient is small (region A). Becomes larger. Kx is about 0.3, for example.

FIG. 9 shows an inductance (L ₂₂ ) of the LC filter of the power receiving unit 200 in the power transmission system 10 shown in FIG. 2 in a situation where the coupling coefficient is large (more specifically, a situation where the coupling coefficient is about 0.6). ) Is a diagram showing the output power factor of the inverter 120 when L _L and L _H are set. As shown in FIG. 9, in the situation the coupling coefficient is larger, than when the L ₂₂ to L _L, more of when the L ₂₂ to L _H is, the output power factor of the inverter 120 becomes high.

FIG. 10 shows an inductance (L ₂₂ ) of the LC filter of the power receiving unit 200 in the power transmission system 10 shown in FIG. 2 in a situation where the coupling coefficient is large (more specifically, a situation where the coupling coefficient is about 0.6). ) Is a diagram showing an output current of the inverter 120 when L is set to L _L and L _H respectively. As shown in FIG. 10, in the situation the coupling coefficient is larger, than when the L ₂₂ to L _L, more of when the L ₂₂ to L _H is, the output current of the inverter 120 becomes smaller. The L ₂₂ when the _{L L,} the output current of the inverter 120 becomes an overcurrent.

FIG. 11 shows the LC filter inductance (L ₂₂ ) in the power transmission system 10 shown in FIG. 2 in a situation where the coupling coefficient is large (more specifically, the situation where the coupling coefficient is about 0.6). ) Is a diagram showing the system efficiency when L is set to L _L and L _H respectively. As shown in FIG. 11, in the situation the coupling coefficient is larger, than when the L ₂₂ to L _L, more of when the L ₂₂ to L _H is, system efficiency is increased.

As described above, in the power transmission system 10 according to this embodiment, when the coupling coefficient is large, the output power factor of the inverter 120 is increased by changing L ₂₂ from L _L to L _H , and the system efficiency is increased. Also gets higher.

In the above embodiment, the initial value of L ₂₂ is set to L _L , but the initial value of L ₂₂ may be set to L _H. The initial value of L ₂₂ when the L _H, when the coupling coefficient is large, not the output current of the inverter 120 is an overcurrent, the output current of the inverter 120 when the coupling coefficient is small becomes overcurrent. The presence or absence of such an overcurrent is monitored, and when an overcurrent occurs (that is, when the coupling coefficient is small), by changing L ₂₂ from L _H to L _L , sufficient inverter 120 in a wide coupling coefficient range is obtained. The output power factor can be secured.

  The circuit configuration of the power transmission system 10 is not limited to the configuration illustrated in FIG. For example, the LC resonance units R1 and R2 are not limited to the series resonance circuit shown in FIG. At least one of the LC resonance units R1 and R2 may be configured by connecting a coil and a capacitor in parallel. Further, the LC filter of the power receiving unit 200 is not limited to the π-type LC filter shown in FIG. 2, but is another type of LC filter (for example, an L-type LC filter omitting the capacitor 205 shown in FIG. 2). May be. Furthermore, the position of the variable inductor 204 constituting the LC filter of the power receiving unit 200 may be changed. FIG. 12 is a diagram illustrating a modification of the circuit configuration of the power transmission system 10. Referring to FIG. 12, variable inductor 204 may be provided in power line PL1 instead of power line PL2.

  The inductance adjusting unit configured to be able to change the inductance of the LC filter of the power receiving unit 200 is not limited to the variable inductor 204. 13 to 15 are diagrams illustrating first to third modifications of the inductance adjusting unit. Instead of the variable inductor 204, inductance adjusting units 204A to 204C shown in FIGS. 13 to 15 may be employed. In these examples, each inductance of the inductance adjusting units 204 </ b> A to 204 </ b> C corresponds to the inductance of the LC filter of the power receiving unit 200.

Referring to FIG. 13, the inductance adjustment unit 204 </ b> A includes a coil 211, a coil 212 connected in parallel to the coil 211, and a switch 213 (L) as elements connected in series to the secondary coil 201 (see FIG. 2). Switch). The coil 212 and the switch 213 are connected in series with each other. The inductance of the inductance adjusting unit 204A varies depending on the state of the switch 213 (ON / OFF). More specifically, when the inductances of the coils 211 and ₂₁₂ are expressed as L ₂₁₁ and L ₂₁₂ , respectively, the inductance of the inductance adjusting unit 204A when the switch 213 is OFF is “L ₂₁₁ ”, and the switch 213 is ON. The inductance of the inductance adjusting unit 204A at this time is “L ₂₁₁ × L ₂₁₂ / (L ₂₁₁ + L ₂₁₂ )”.

Referring to FIG. 14, the inductance adjusting unit 204 </ b> B includes coils 221 and 222 as elements connected in series to the secondary coil 201 (see FIG. 2), and a switch 223 (L switch connected in parallel to the coil 222). ). The coils 221 and 222 are connected in series with each other. The inductance of the inductance adjusting unit 204B varies depending on the state (ON / OFF) of the switch 223. More specifically, when the inductances of the coils ₂₂₁ and ₂₂₂ are expressed as L ₂₂₁ and L ₂₂₂ , respectively, the inductance of the inductance adjusting unit 204B when the switch 223 is OFF is “L ₂₂₁ + L ₂₂₂ ”, and the switch 223 is ON. The inductance of the inductance adjusting unit 204B is “L ₂₂₁ ”.

Referring to FIG. 15, the inductance adjusting unit 204 </ b> C includes a coil 231 and a capacitor 232 as elements connected in series to the secondary coil 201 (see FIG. 2), and a switch 233 connected in parallel to the capacitor 232. Consists of including. The coil 231 and the capacitor 232 are connected in series with each other. The inductance of the inductance adjusting unit 204C varies depending on the state (ON / OFF) of the switch 233. The inductive reactance of the inductance adjusting unit 204C increases as the inductance of the inductance adjusting unit 204C increases. When the inductance of the coil 231 is expressed as L ₂₃₁ and the capacitance of the capacitor 232 is expressed as C ₂₃₂ , the inductive reactance of the inductance adjusting unit 204C when the switch 233 is OFF is “ωL ₂₃₁ − (1 / ωC ₂₃₂ )”. The inductive reactance of the inductance adjusting unit 204C when 233 is ON is “ωL ₂₃₁ ”. Note that “ωL ₂₃₁ ” is larger than “1 / ωC ₂₃₂ ”.

  In the processing of FIGS. 5 to 7, the switches 213, 223, and 233 (FIGS. 13 to 15) are used to change the inductance of the LC filter of the power receiving unit 200 after stopping the power transmission and to resume power transmission after the change. Therefore, it is not necessary to use a semiconductor relay with a high response speed, and it is possible to use a mechanical relay that is easily available at a lower cost than a semiconductor relay. However, the type of each switch is not limited to a mechanical relay. A semiconductor relay may be employed instead of the mechanical relay.

  The method for determining whether the coupling coefficient is large or small can be arbitrarily changed. For example, the vehicle 2 may further include a distance measuring sensor that detects the inter-coil distance ΔG (FIG. 1). As the distance measuring sensor, an ultrasonic sensor, a laser distance measuring sensor, or the like can be adopted. The vehicle ECU 500 may determine whether the coupling coefficient is large or small based on the detection value of the distance measuring sensor. Since the coupling coefficient decreases as the inter-coil distance ΔG increases, the vehicle ECU 500 determines that the coupling coefficient is large when the inter-coil distance ΔG is smaller than a predetermined value, and when the inter-coil distance ΔG is larger than the predetermined value. It can be determined that the coupling coefficient is small.

  The processing in FIGS. 5 to 7 is an example of power transmission / reception control, and is not limited thereto. For example, after performing an extreme value search of the drive frequency of the inverter 120 (search for a frequency at which power loss is minimized), the duty of the output voltage of the inverter 120 is adjusted to an optimum value at the searched frequency (extreme value). Also good.

  The target device to which power is supplied from the power receiving unit 200 is not limited to the power storage device 300, and may be any electric load (such as an in-vehicle device).

Each of the above modifications may be implemented by combining all or some of them.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Charging equipment, 2 Vehicles, 10 Power transmission system, 100 Power transmission unit, 101 Primary coil, 102, 103, 202, 203, 205, 207, 232 Capacitor, 104, 211, 212, 221, 222, 231 Coil, 120 Inverter, 130 AC / DC converter, 140 Power monitoring unit, 150 Power transmission ECU, 160,600 Communication unit, 181 Voltage sensor, 182, 183, 184, 283, 284 Current sensor, 200 Power receiving unit, 201 Secondary coil, 204 Variable Inductor, 204A, 204B, 204C Inductance adjuster, 206 Rectifier circuit, 213, 223, 233 Switch, 300 Power storage device, 310 Monitoring unit, 400 Charging relay, 500 Vehicle ECU, 700 AC power supply, F1, F Filter circuit, R1, R2 LC resonance part.

Claims (1)

A non-contact power receiving device that receives power transmitted from a primary coil of a power transmission device in a non-contact manner by a secondary coil and supplies the power to a target device,
An LC resonance unit configured by connecting the secondary coil and the capacitor in series or in parallel;
An LC filter provided between the LC resonance unit and the target device;
The LC filter includes an inductance adjusting unit configured to change the inductance,
The non-contact power receiving apparatus further includes a control unit that controls the inductance adjusting unit,
The controller determines whether a coupling coefficient between the primary coil and the secondary coil is large or small, and determines the inductance of the LC filter when the coupling coefficient is large, and the LC when the coupling coefficient is small. A non-contact power receiving device that is larger than the inductance of the filter.

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