JP2016015862A - Power reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of an element in a power reception device.SOLUTION: A load circuit 13, including a serially connected load and a switching element, is disposed between a pair of output ends of a power reception side power converter 12. The load of the load circuit 13 includes a resistance value in order that the element voltage of a power reception side pad 11 or the power reception side power converter 12 does not reach a withstanding voltage before the suspension of power supply caused by the transmission of a power supply suspension request from a power reception device R to a power transmission device S, at the connection of the switching element by the release of connection to a load device B.

Description

  The present invention relates to a power receiving apparatus.

  Patent Document 1 listed below includes a power supply facility having a primary self-resonant coil, a hybrid vehicle having a secondary self-resonant coil that receives power from the primary self-resonant coil via an electromagnetic field, and charging the battery with the received power There is disclosed a non-contact power feeding system including a power receiving device and a control device that controls power feeding from a primary self-resonant coil to a secondary self-resonant coil by controlling a high-frequency power device.

JP 2010-252446 A

  By the way, in the above prior art, normally, a switch is provided to protect the battery from overvoltage and overcurrent, and when the switch is open during power feeding, a power supply stop request is transmitted from the power receiving device to the power transmitting device. However, between the time when the power supply stop request is transmitted and the time when power supply is actually stopped, the power supplied from the power transmission device increases the voltage of the elements in the power receiving pad of the power receiving device and the power receiving side power converter. There is a problem that the element is damaged.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to prevent element breakage in a power receiving apparatus.

  In order to achieve the above object, in the present invention, as a first solving means, a power receiving side pad that receives power that is contactlessly fed from a power transmitting device, power received by the power receiving side pad, and a load are converted. A power receiving device comprising a power receiving side power converter to be supplied to the device, comprising a load circuit comprising a load and a switching element connected in series between a pair of output ends of the power receiving side power converter. When the switching element is turned on due to opening of the connection to the load device, the load of the load circuit is received before the power supply is stopped by transmission of a power supply stop request from the power reception device to the power transmission device. A means is adopted that has a resistance value for preventing the voltage of the side pad or the element of the power receiving side power converter from reaching the withstand voltage.

  In the present invention, as the second solving means, in the first solving means, a control unit for controlling the switching element is provided, and the control unit outputs an output voltage of the power receiving side pad or the power receiving side power converter. When the value exceeds a threshold value, a means is adopted in which the switching element is turned on.

  In the present invention, as a third solution means, in the first solution means, comprising a switch provided between the load circuit and the load device, and a control unit for controlling the switching element, The control unit employs means for turning on the switching element when the connection to the load device is opened because the switch is in the off state.

  In the present invention, as the fourth solving means, in the first to fourth solving means, a means that the power supply stop request is transmitted wirelessly is adopted.

  According to the present invention, a load circuit including a load and a switching element connected in series is provided between a pair of output ends of a power receiving side power converter, and the load of the load circuit is opened to a load device. In order to prevent the voltage of the power receiving side pad or the power receiving side power converter element from reaching the withstand voltage before the power feeding is stopped by sending a power supply stop request from the power receiving device to the power transmitting device when the switching element is turned on By having this resistance value, it is possible to prevent damage to elements in the power receiving device.

It is a functional block diagram of the non-contact electric power feeding system which comprises the power receiving apparatus which concerns on one Embodiment of this invention. It is a circuit diagram of the non-contact electric power feeding system which comprises the power receiving apparatus which concerns on one Embodiment of this invention. It is a graph which shows the output voltage of the receiving side rectifier circuit of the power receiving apparatus which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The power receiving device R according to the present embodiment constitutes a part of the non-contact power feeding system. As shown in FIGS. 1 and 2, the non-contact power supply system includes a power transmission device S and a power reception device R. As illustrated, the power transmission device S includes a power transmission side power converter 1, an inverter circuit 2, a power transmission side pad 3, a power transmission side current / voltage sensor 4, a power transmission side communication unit 5, and a power transmission side control unit 6. ing.

  On the other hand, the power receiving device R includes a power receiving side pad 11, a power receiving side power converter 12, a load circuit 13, a switch 14, a power receiving side current / voltage sensor 15, a power receiving side communication unit 16, and a power receiving side control unit 17. Yes.

  The power transmission device S is a device that is fixedly arranged in a power supply facility provided on the ground and supplies AC power to the power reception device R provided on the moving body in a contactless manner. The power feeding facility is a facility provided with one or a plurality of stopping spaces for moving bodies, and includes a power transmission device S corresponding to the number of stopping spaces. On the other hand, the power receiving device R is a device that is provided in the moving body and charges the battery B (load device) by converting AC power supplied from the power transmission device S into DC power. In addition, the said mobile body is a vehicle which requires the power receiving from the outside, such as an electric vehicle and a hybrid vehicle, for example.

In the power transmission device S, the power transmission side power converter 1 includes a power transmission side rectifier circuit 1a and a chopper circuit 1b.
The power transmission side rectifier circuit 1a is, for example, a diode bridge, and full-wave rectifies commercial power (for example, single phase 100 volts, 50 Hz) supplied from an external commercial power source and outputs the rectified power to the chopper circuit 1b. The power (full-wave rectified power) supplied from the power transmission side rectifier circuit 1a to the chopper circuit 1b is a unipolar (for example, positive polarity) pulsating current obtained by folding the sine wave-shaped commercial power at the zero cross point.

  The chopper circuit 1 b adjusts its output voltage and outputs it to the inverter circuit 2 by the switching operation being controlled by the power transmission side control unit 6. Specifically, the chopper circuit 1b is a step-up chopper circuit or a step-up / step-down chopper circuit, and steps up and down the electric power input from the power transmission side rectifier circuit 1a and outputs it. The output of the chopper circuit 1b is DC power in which the full-wave rectified power that is a pulsating current is sufficiently smoothed by the function of a capacitor provided at the output terminal of the chopper circuit 1b.

  Further, the chopper circuit 1b functions as a power factor correction circuit (PFC) by controlling the switching operation by the power transmission side control unit 6. That is, the chopper circuit 1b switches the full-wave rectified power at a frequency sufficiently higher than the frequency of the full-wave rectified power with reference to the zero-cross point of the full-wave rectified power. Increase the power factor by extending the period. In general, since it is well known that the chopper circuit 1b functions as a power factor correction circuit, a detailed description of the power factor improvement principle of the chopper circuit 1b is omitted here.

  The inverter circuit 2 converts the DC power supplied from the power transmission rectifier circuit 1a into AC power having a predetermined frequency (drive frequency) based on a switching signal (inverter drive signal) input from the power transmission side control unit 6. It is a conversion circuit. That is, the inverter circuit 2 converts the DC power into AC power at the drive frequency by driving a plurality of switching elements by the inverter drive signal. Such an inverter circuit 2 outputs the AC power to the power transmission side pad 3.

  The power transmission side pad 3 is a circuit having a power transmission coil 3a and a power transmission capacitor. Among the power transmission coil 3a and the power transmission capacitor, the power transmission coil 3a is provided at a position facing a predetermined location (location where the power receiving coil 11a is provided) of the moving body stopped in the stop space.

  The power transmission side current / voltage sensor 4 detects the current and voltage of power supplied from the commercial power source to the power transmission side rectifier circuit 1 a and outputs a detection signal indicating the detected current and voltage to the power transmission side control unit 6. As the current sensor, for example, a sensor that measures the magnetic field generated around the wire through which the current passes by the Hall effect, or a sensor that measures the potential drop caused by the resistance by inserting a resistor into the wire through which the current passes can be used. is there. As a voltage sensor, for example, there is a sensor that divides a voltage with a resistor and converts the voltage into a digital value by an AD (Analog to Digital) converter.

  The power transmission side communication unit 5 performs near field communication with the power reception side communication unit 16 of the power receiving device R. Note that the communication method between the power transmission side communication unit 5 and the power reception side communication unit 16 is short-distance wireless communication such as ZigBee (registered trademark) or Bluetooth (registered trademark) or short-distance optical communication using an optical signal. The power transmission side communication unit 5 has an antenna in the case of a communication method using radio waves, and has a light receiving element for communication in the case of a communication method using an optical signal.

  The power transmission side control unit 6 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an interface circuit that transmits and receives various signals to and from each of the electrically interconnected units. Yes. The power transmission side control unit 6 controls various operations of the power transmission device S by performing various arithmetic processes based on various arithmetic control programs stored in the ROM and communicating with the respective units. The details of the operation of the power transmission side control unit 6 will be described later.

  On the other hand, in the power receiving device R, the power receiving side pad 11 is a circuit having a power receiving coil 11a and a power receiving capacitor. The power receiving coil 11a is provided at the bottom, side, top, or the like of the moving body, and faces the power transmitting coil 3a constituting the power transmitting apparatus S in a state where the moving body stops in the stop space.

  In such a power receiving side pad 11, the power receiving coil 11 a is magnetically coupled so as to face and face the power transmitting coil 3 a constituting the power transmitting side pad 3. That is, the power receiving side pad 11 receives the AC power supplied to the power transmitting coil 3a by the inverter circuit 2 and the AC power corresponding to the coupling coefficient between the power transmitting coil 3a and the power receiving coil 11a from the power transmitting side pad 3 without contact. It outputs to the power receiving side rectifier circuit 12a. That is, this non-contact power feeding system is a non-contact power feeding system that conforms to a magnetic field resonance method, an electromagnetic induction method, or the like.

In the power receiving device R, the power receiving side power converter 12 converts the power received from the power transmitting side pad 3 of the power transmitting device S through the power receiving side pad 11 into power to be supplied to the battery B. It comprises a side rectifier circuit 12a and a filter circuit 12b.
The power receiving side rectifier circuit 12a is composed of, for example, a diode bridge, and full-wave rectifies the AC power (received power) supplied from the power receiving side pad 11 and outputs it to the filter circuit 12b. The power supplied from the power receiving side rectifier circuit 12a to the filter circuit 12b is full-wave rectified power that is full-wave rectified by a diode bridge.

  The filter circuit 12b includes, for example, a reactor and a capacitor. The filter circuit 12b removes noise from the full-wave rectified power supplied from the power receiving side control unit 17 and smoothes it, and outputs it to the battery B. Moreover, the said reactor is a variable reactor, for example.

  The load circuit 13 is provided between the filter circuit 12b and the switch 14, and includes, for example, a resistor 13a and a switching element 13b. In the load circuit 13, the switching element 13 b is switched between an on state and an off state based on control by the power receiving side control unit 17. For example, an IGBT (Insulated Gate Bipolar Transistor), a bipolar transistor, a MOSFET (Metal-Oxide-) Semiconductor Field-Effect Transistor). For example, the switching element 13b is turned on when a switch 14 described later is turned off. The resistance value of the resistor 13a is preferably higher than the rated impedance of the battery B. Since the power consumed by the resistor 13a can be reduced, the resistor 13a can be reduced in size. The rated impedance is a range of impedance that can be taken in a desired use situation of the battery B. For example, when the voltage of the battery B is 300 [V] and the desired power supply amount is 3 [kW], 10 [ A] Since the current flows, the impedance of the battery B is 30 [Ω]. Since the voltage of the battery B changes depending on the state of charge (SOC), the impedance of the battery B changes accordingly. When desired power is supplied to the battery B, the impedance range that the battery B can take is the rated impedance.

  The switch 14 is provided between the load circuit 13 and the battery B, and switches between an on state and an off state based on control by the power receiving side control unit 17. For example, a switch, an electromagnetic contactor, a circuit breaker, or the like This is realized by a circuit having a function of opening and closing the circuit. The switch 14 is provided to prevent the battery B from overcurrent and overvoltage, for example. When the switch 14 is turned off, the connection to the battery B is released.

  The power receiving side current / voltage sensor 15 detects the current and voltage of the DC power supplied from the filter circuit 12 b to the load circuit 13, and outputs a detection signal indicating the detected current and voltage to the power receiving side control unit 17. As the current sensor, for example, a sensor that measures the magnetic field generated around the wire through which the current passes by the Hall effect, or a sensor that measures the potential drop caused by the resistance by inserting a resistor into the wire through which the current passes can be used. is there. As a voltage sensor, for example, there is a sensor that divides a voltage with a resistor and converts the voltage into a digital value with an AD converter.

  The power receiving side communication unit 16 performs near field communication with the power transmission side communication unit 5 of the power transmission device S. Note that the communication method between the power transmission side communication unit 5 and the power reception side communication unit 16 is short-distance wireless communication such as ZigBee (registered trademark) or Bluetooth (registered trademark) or short-distance optical communication using an optical signal. The power receiving side communication unit 16 has an antenna in the case of a communication method using radio waves, and has a light emitting element for communication in the case of a communication method using an optical signal.

  The power receiving side control unit 17 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an interface circuit that transmits and receives various signals to and from each of the electrically connected units. Yes. The power receiving side control unit 17 performs various arithmetic processes based on various arithmetic control programs stored in the ROM and controls the overall operation of the power receiving device R by communicating with each unit. The details of the operation of the power receiving side control unit 17 will be described later.

  The battery B is a secondary battery such as a lithium ion battery or a nickel hydride secondary battery, and charges and stores DC power supplied from the power receiving side rectifier circuit 12a. The battery B is connected to an inverter (traveling inverter) that drives a traveling motor of the mobile body and / or a control device that controls the traveling of the mobile body, and supplies driving power to the traveling inverter and the control device. To do.

  Next, the operation of the non-contact power feeding system configured as described above will be described in detail.

  In this non-contact power feeding system, the power receiving side control unit 17 of the power receiving device R of the moving body includes the switch 14 and the switching element 13b of the load circuit 13 when power is not supplied (for example, during normal operation of the moving body by the driver). Turn off. On the other hand, the power transmission side control unit 6 of the power transmission device S stops the chopper circuit 1b and the inverter circuit 2 at the time of non-power feeding, that is, when the moving object to be fed is not stopped at the parking / stopping position.

  Thereafter, the user operates the power receiving device R, moves the power receiving device R to the installation location of the power transmitting device S, and stops the power receiving device R. The power receiving side control unit 17 of the power receiving device R grasps the installation position of the power transmitting device S from the output of a position sensor such as a sound wave sensor or an optical sensor (not shown). When the power receiving side control unit 17 detects that the power receiving device R has moved until it faces the power transmitting device S from the output of the position sensor such as the sound wave sensor or the optical sensor as described above, the switch 14 is switched from the OFF state to the ON state. To.

  On the other hand, the power transmission side control unit 6 of the power transmission device S grasps the position of the power reception device R from the output of a position sensor such as a sound wave sensor or an optical sensor (not shown) as with the power reception device R. When the power transmission side control unit 6 detects that the power receiving device R has moved up from the output of the position sensor such as a sound wave sensor or an optical sensor until the power receiving device R faces the power transmitting device S, the chopper circuit 1b and the inverter circuit 2 is driven to cause the chopper circuit 1b and the inverter circuit 2 to start a power feeding operation.

  On the other hand, the power receiving side control unit 17 of the power receiving device R determines the overvoltage or overcurrent to the battery B based on the detection signal input from the power receiving side current / voltage sensor 15, and the overvoltage or overcurrent to the battery B is detected. If it is determined that the battery B is generated, the switch 14 is turned from the on state to the off state in order to protect the battery B. Subsequently, the power receiving side control unit 17 causes the power receiving side communication unit 16 to transmit a power supply stop request and turns on the switching element 13b. Note that the determination of overvoltage and overcurrent includes not only actual determination of overvoltage and overcurrent but also erroneous determination based on sequence error and error data of the power receiving side current / voltage sensor 15. Further, the state of the switch 14 is not limited to switching due to overvoltage or overcurrent, and may be switched due to, for example, an increase in the temperature of the battery B.

  On the other hand, when the power transmission side communication unit 5 receives the power supply stop request from the power receiving device R, the power transmission side control unit 6 of the power transmission device S stops driving the chopper circuit 1b and the inverter circuit 2, and the chopper circuit 1b and the inverter The circuit 2 stops the power feeding operation.

  In the power receiving device R, when the power receiving side communication unit 16 transmits the power supply stop request, the switching element 13b is turned on, so that the power supply from the power transmitting device S is stopped until the power supply by the power transmitting device S is stopped. The electric power is supplied to the resistor 13a and consumed.

  For example, when the resistor 13a is not connected to the power receiving side power converter 12 as in the prior art, the power receiving power is received after the power receiving side communication unit 16 transmits a power supply stop request until the power supply is actually stopped. The voltage of the power receiving side pad 11 and the power receiving side power converter 12 of the device R increases (see FIG. 3). This is because the power supplied from the power transmitting device S to the power receiving device R is not supplied to the battery B and is not consumed because the switch 14 is in the off state. As a result, the voltage of the elements constituting the power receiving side pad 11 and the power receiving side power converter 12 of the power receiving device R rises and is damaged.

  On the other hand, in the present embodiment, even if the switch 14 is in an off state and the supplied power is not supplied to the battery B, the power is consumed by the resistor 13a, so that the power receiving side pad 11 of the power receiving device R and the power receiving side power conversion are used. An increase in the voltage of the elements constituting the vessel 12 can be suppressed.

  When the switching element 13b is turned on, the resistor 13a transmits a power supply stop request from the power receiving device R to the power transmitting device S and is stopped until the power supply is stopped. It has a resistance value for preventing the voltage of the element from reaching the breakdown voltage.

  Specifically, the resistance value of the resistor 13a is determined by the following method at the design stage or the like. First, the time from when the switch 14 is switched to the OFF state to when the power supply is stopped through the transmission of the power supply stop request is calculated. Next, a resistor having a resistance value that is considered not to reach the withstand voltage of an element (for example, an element with the lowest withstand voltage) that is most likely to be damaged among the power receiving side pad 11 or the power receiving side power converter 12 is provided. In the calculated time, it is confirmed whether or not the breakdown voltage of the element having a high possibility of damage is exceeded. If not, gradually increase the resistance value, check whether the breakdown voltage of the element with high possibility of damage is exceeded within the calculated time, and check if the element with high possibility of damage is within the calculated time. The highest resistance value that does not exceed the withstand voltage is derived. Since the resistor has a higher resistance value, heat generation is suppressed, and thus the surface area can be reduced. That is, the resistor can be made smaller as the resistance value is higher.

  When the switch 14 is controlled by a control device different from the power receiving side control unit 17, the power receiving side control unit 17 applies the switching element 13 b to the switching element 13 b based on the detection signal input from the power receiving side current / voltage sensor 15. It may be determined whether or not to turn on. That is, when the switch 14 is turned off from the on state during power feeding, the voltage detected by the power receiving side current / voltage sensor 15 rises and exceeds the threshold value. The switching element 13b is turned on (see FIG. 3). At this time, similarly to the above operation, the power receiving side communication unit 16 is caused to transmit a power supply stop request.

  According to this embodiment, the load circuit 13 including the resistor 13a and the switching element 13b connected in series is provided between the pair of output terminals of the power receiving side power converter 12, and the load circuit 13 When the switching element 13b is connected, the resistor 13a is connected to the voltage of the element of the power receiving side pad 11 or the power receiving side power converter 12 until power supply is stopped by transmission of a power supply stop request from the power receiving apparatus R to the power transmitting apparatus S. By having a resistance value for preventing the voltage from reaching the breakdown voltage, it is possible to prevent damage to the elements in the power receiving device R.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the power transmission device S, the chopper circuit 1b is used as a voltage converter. However, instead of the chopper circuit 1b that is a non-insulated voltage converter, a transformer that is an insulated voltage converter is used. Also good. In the power transmission device S, a full bridge is used as the power transmission side rectifier circuit 1a and the power reception side rectifier circuit 12a. However, a half bridge may be used instead of the full bridge. In the above embodiment, the power receiving side power converter 12 includes the power receiving side rectifier circuit 12a and the filter circuit 12b. However, a voltage converter may be provided at the subsequent stage of the filter circuit 12b depending on the load device. .

  Further, although the battery B is provided as the load device, a DC load other than the battery B or an AC load may be provided. In addition, when providing AC load, it is necessary to set it as the structure from which AC power is output from the power receiving side power converter 12. FIG. Moreover, although the commercial power supply which is AC power supply is used, you may use DC power supply. In addition, when providing DC power supply, it is necessary to delete the power transmission side rectifier circuit 1a from the power transmission side power converter 1. FIG.

(2) In the above embodiment, as a modification, the power receiving side control unit 17 turns on the switching element 13b based on the detection result by the power receiving side current / voltage sensor 15 provided in the subsequent stage of the filter circuit 12b. Although it is determined whether or not, the present invention is not limited to this. For example, a voltage sensor is provided between the power receiving side pad 11 and the power receiving side rectifier circuit 12a, or between the power receiving side rectifier circuit 12a and the filter circuit 12b, and the power receiving side control unit 17 displays the detection result by the voltage sensor. Based on this, it may be determined whether or not the switching element 13b is turned on. That is, when the result detected by the voltage sensor exceeds the threshold value, the power receiving side control unit 17 turns on the switching element 13b.

(3) The resistor 13a is not limited as long as it consumes power as a load. For example, a reactor having the above-described resistance value may be used instead of the resistor 13a.

(4) In the above embodiment, when the switch 14 is turned off, the connection to the battery B is released, and the voltages of the elements constituting the power receiving side pad 11 and the power receiving side power converter 12 of the power receiving device R are reduced. Although described as rising, the present invention is not limited to this embodiment. For example, the present invention can also be applied to the case where the connection between the battery B and the voltage in the power receiving device R increases due to the disconnection of the wiring between the load circuit 13 and the battery B. In this case, the power receiving side control unit 17 can turn on the switching element 13b when the voltage detected by the power receiving side current / voltage sensor 15 exceeds the threshold value.

(5) In the above embodiment, it has been described that the switching of the switching element 13b between the on state and the off state is performed by the power receiving side control unit 17 based on the detection signal of the power receiving side current / voltage sensor 15. The switching control of 13b is not limited to the software control of the power receiving side control unit 17. For example, an operational amplifier / comparator to which an output voltage of the load circuit 13 and a predetermined voltage (a reference voltage determined to be an overvoltage) are input is provided. The operational amplifier / comparator has an output voltage of the load circuit 13 that is equal to or higher than a predetermined voltage. In this case, a signal is output. The output of the operational amplifier / comparator is connected to the control terminal of the switching element 13b such as an IGBT or a bipolar transistor, whereby the switching element 13b is switched to an ON state when an overvoltage occurs. As described above, the switching of the switching element 13b can be realized in hardware without depending on the software processing of the power receiving side control unit 17.

DESCRIPTION OF SYMBOLS S Power transmission apparatus R Power reception apparatus B Battery 1 Power transmission side power converter 2 Inverter circuit 3 Power transmission side pad 4 Power transmission side current / voltage sensor 5 Power transmission side communication part 6 Power transmission side control part 11 Power reception side pad 12 Power reception side power converter 13 Load Circuit 14 Switch 15 Power-receiving-side current / voltage sensor 16 Power-receiving-side communication unit 17 Power-receiving-side control unit 1a Power-transmission-side rectifier circuit 1b Chopper circuit 3a Power-transmission coil 11a Power-receiving coil 12a Power-receiving-side rectifier circuit 12b Filter circuit 13a Resistor 13b Switching element

Claims (4)

A power receiving device comprising: a power receiving side pad that receives power contactlessly fed from a power transmitting device; and a power receiving side power converter that converts power received by the power receiving side pad and supplies the power to a load device,
Between the pair of output terminals of the power receiving side power converter, comprising a load circuit composed of a load and a switching element connected in series,
The load of the load circuit is configured such that when the switching element is turned on due to opening of the connection to the load device, power supply is stopped by transmission of a power supply stop request from the power reception device to the power transmission device. A power receiving device having a resistance value for preventing a voltage of a pad or an element of the power receiving side power converter from reaching a withstand voltage. Comprising a control unit for controlling the switching element;
The power reception device according to claim 1, wherein the control unit turns on the switching element when an output voltage of the power reception side pad or the power reception side power converter exceeds a threshold value. A switch provided between the load circuit and the load device; and a control unit for controlling the switching element,
The power receiving device according to claim 1, wherein the control unit turns the switching element on when the connection to the load device is opened due to the switch being off.   The power receiving device according to claim 1, wherein the power supply stop request is transmitted wirelessly.

Images