JP2012050286A - Non-contact power feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect whether or not a load is connected to a power reception device using a power transmission device based on an unloaded state in standby operation, without requiring the electric power energy on the power reception side to which an electric power is supplied from the power transmission device to the power reception device in a non-contact manner, and to make the electric power transmitted to the power reception device be a constant effective power.SOLUTION: In a phase difference detection circuit 108, an erroneous detection is prevented which is caused by harmonics and spurious component from a power amplification part 102 which are generated by fluctuation of a load from an unloaded state in standby operation, without requiring the electric energy on the power reception side to which an electric power is supplied from a power transmission device 1 to a power reception device 2 in a non-contact manner. In the circuit, whether or not a load 3 is connected to the power reception device is detected. Even if a state of the load fluctuates due to charging operation or the like while power transmission to the load is continued, an effective power by power transmission to the load is assured as a constant power value. Power transmission is performed only in such normal state as a link coil L11 of the power transmission device is connected without disconnection.

Description

  The present invention relates to a non-contact power feeding device that supplies power from a power transmission device to a power receiving device in a non-contact manner, and relates to a non-contact power feeding device having a load detection unit provided on the power receiving device side.

  Conventionally, in a non-contact power supply device for the purpose of non-contact power supply to a load (load device), it is difficult to control power transmission based on load detection or human operation. Even when no load is present, the apparatus generally continues to transmit power, and there has been a problem that meaningless power transmission occurs. Therefore, in order to prevent meaningless power transmission, it is necessary to have means for transmitting power only when the power supply device side detects the presence of the receiving side in a non-contact manner and the receiving side is within a power transmission range. . Such a detection means includes a permanent magnet on the receiver side, a magnetic switch on the power transmission side, and a means for supplying power only during a period in which the permanent magnet is on. A contact charger is known (for example, refer to Patent Document 1).

  Moreover, in recent years, as a non-contact power transmission (non-contact power transmission) that uses electromagnetic induction and enables power transmission even without a metal part contact, a power transmission device (secondary side) to a power transmission device (primary side) ) Is realized by so-called load modulation, and the power transmission device detects the induced voltage of the primary coil by a comparator or the like, so that the power receiving side (secondary side) associated with the insertion of foreign matter or data transmission There is known a non-contact power transmission device that detects a change in the load state (see, for example, Patent Document 2).

JP-A-8-126230 JP 2006-60909 A

  However, according to the non-contact type charger described in Patent Document 1, since the magnetic field is emitted from the permanent magnet of the load device to the outside, not only the outside is adversely affected but also the non-contact distance can be increased. It was difficult.

  Moreover, according to the non-contact power transmission device described in Patent Document 2, since the load state on the power receiving side is detected by comparing the peak voltage of the induced voltage with a predetermined threshold voltage, the power supply voltage fluctuations and between the coils The threshold voltage used for determining the detection voltage also varies due to variations in the distance and position of each element and variations in element constants such as coil inductance, making it difficult to properly detect the load state on the power receiving side. There is a difficulty in using the power receiving side energy for the detection.

  The present invention has been made to solve these problems, and does not require power energy on the power receiving side that is supplied in a contactless manner from the power transmitting device to the power receiving device, and receives power from a no-load state during standby operation. It is an object of the present invention to provide a non-contact power feeding device that detects whether or not a load is connected to the device by the power transmission device and uses the transmitted power to the power receiving device as a constant execution power.

  In order to achieve the above-described object, a non-contact power feeding device according to a first aspect of the present invention includes a power transmission side resonator of a power transmission device and a power reception side resonator of a power reception device each having a predetermined parallel resonance frequency in a near electromagnetic field. This device supplies the power generated by the power transmission device to the power receiving device in a non-contact manner due to magnetic field coupling generated between the power receiving device and the power receiving device. The power transmission device includes an oscillator for generating a traveling wave power signal propagating in a forward direction, a power amplification unit for amplifying the traveling wave power signal generated by the oscillator, and a traveling wave power signal from the power amplification unit And a directional coupler for simultaneously extracting reflected wave power signals propagating in the reverse direction, an arithmetic unit for multiplying the traveling wave power signal and reflected wave power signal extracted by the directional coupler, and an arithmetic unit A phase change detector for detecting the change in the phase difference between the traveling wave power signal and the reflected wave power signal based on the result of the calculation and determining the presence or absence of a load connected to the power receiving resonator of the power receiving device; I have.

  Moreover, the non-contact electric power feeder which is the 2nd aspect of this invention is equipped with the band pass filter for interrupting | blocking frequency components other than the frequency which an oscillator oscillates in the 1st aspect of this invention. Yes.

  In addition, the non-contact power feeding apparatus according to the third aspect of the present invention is the first aspect of the present invention, wherein the power transmission apparatus determines whether or not there is a load based on the detection result of the phase change detection unit. And a control unit for varying the amplification gain of the power amplification unit within a predetermined time measured by the timer.

  The contactless power supply device according to the fourth aspect of the present invention is the amplitude difference detection for detecting the amplitude difference between the traveling wave power signal and the reflected wave power signal in the power transmission device according to the first aspect of the present invention. A circuit and a control unit for varying the amplification gain of the power amplification unit so that the amplitude difference is constant are provided.

  Moreover, the non-contact electric power feeder which is the 5th aspect of this invention is a 1st aspect of this invention. WHEREIN: A directional coupler is couple | bonded with the power transmission side resonator via the link coil for performing impedance conversion. Has been. The power transmission device is connected to a link coil and has an impedance variable element that has a low impedance for DC and a high impedance for a high frequency, and the link coil is disconnected when a direct current flows through the link coil via the impedance variable element. And a state detecting unit for detecting a normal state of being connected.

  Further, the non-contact power feeding device according to the sixth aspect of the present invention is the power transmission device according to the fifth aspect of the present invention, wherein the power transmission device controls the power amplification unit and detects the direction from the oscillator when the detection unit detects a normal state. A control unit for executing power transmission to the sex coupler is provided.

  According to the non-contact power supply device of the present invention, power amplification caused by a load variation from a no-load state during standby operation without requiring the power energy on the power receiving side that is supplied in a non-contact manner from the power transmitting device to the power receiving device. In the phase difference detection circuit that prevents erroneous detection due to harmonics and spurious components from the unit, it is possible to detect whether or not a load is connected to the power receiving device. Even when the load changes its state due to a charging operation or the like, the execution power due to power transmission to the load does not decrease and is secured at a constant power value. In addition, since power transmission is executed only in a normal state where the link coil of the power transmission device is not disconnected and connected, in an abnormal state where the link coil is disconnected or disconnected, for example, a short circuit A failure in the mode can be easily prevented.

FIG. 1 is a circuit block diagram showing a specific configuration of a non-contact power feeding apparatus according to an embodiment of the present invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments to which a non-contact power feeding device according to the invention is applied will be described with reference to the drawings.

  FIG. 1 is a circuit block diagram showing a specific configuration of a non-contact power feeding apparatus according to an embodiment of the present invention. This non-contact power feeding device receives, for example, power transmission side resonator 100 of power transmission device 1 and power reception device 2 each having predetermined parallel resonance frequencies f1 and f2 described later in a near electromagnetic field that is a frequency environment of 400 kHz to 20 MHz. Electric power generated in the power transmitting device 1 is supplied to the power receiving device 2 in a non-contact manner by magnetic field coupling (electromagnetic field coupling) generated between the side resonator 200 and the side resonator 200.

  Next, in describing the configuration of the power transmission device 1, the power transmission device 1 includes a power transmission resonator 100, an oscillator 101, a power amplification unit 102, a directional coupler 103, (two) bandpass filters (hereinafter, Traveling wave BPF and reflected wave BPF) 104a, 104b, (two) distributors (hereinafter referred to as traveling wave distributor and reflected wave distributor) 105a, 105b, arithmetic unit 106, low-pass filter ( (Hereinafter referred to as LPF) 107, a phase change detection unit 108, an amplitude difference detection circuit 109, a smoothing capacitor C11, a (power transmission) link coil L11, an impedance variable element L12, a state detection unit 110, and a control unit 111. .

  In the power transmission device 1, the power transmission-side oscillator 100 includes a pickup coil L10 and a resonance capacitor C10 having a parallel resonance frequency f1 expressed by the equation (1) connected in parallel, and a high frequency (harmonic) connected to the link coil L11. The pickup coil L10 receives a magnetic field generated by the flow of current, amplifies the current obtained by this electromagnetic induction action, and controls it to a constant current.

  The oscillator 101 is for generating, for example, a 1 mW signal wave of the traveling wave power signal Pf propagating in the forward direction. The power amplifying unit 102 amplifies the traveling wave power signal Pf generated by the oscillator 101, the amplification gain of which is controlled by the control unit 111, and transmits the amplified signal as, for example, a 100 W strong radio wave signal. It is. Furthermore, the directional coupler 103 is connected to the power transmission side resonator 100 via the link coil L11 with the link coil L11 connected via the smoothing capacitor C11. The traveling wave power signal Pf (phase signal and amplitude signal) and the reflected wave power signal Pr propagating in the opposite direction (phase signal and amplitude signal) can be taken out simultaneously.

  The traveling wave BPF 104 a is a frequency component other than the frequency oscillated by the oscillator 101 among the frequency components of the traveling wave power signal Pf (phase signal and amplitude signal) extracted by the directional coupler 103, that is, the fundamental wave. This is for blocking frequency components other than. Further, the reflected wave BPF 104 b blocks frequency components other than the similar fundamental wave oscillated by the oscillator 101 from the frequency components of the reflected wave power signal Pr (phase signal thereof) extracted by the directional coupler 103. Is for.

  The traveling wave distributor 105a is for distributing and transmitting the output signal from the traveling wave BPF 104a to the arithmetic unit 106 and the amplitude difference detection circuit 109, respectively. The reflected wave distributor 105b is used to distribute and output the output signal from the reflected wave BPF 104b to the arithmetic unit 106 and the amplitude difference detection circuit 109, respectively.

  The computing unit 106 is a traveling wave power signal Pf (phase signal and amplitude signal) and a reflected wave power signal Pr (phase signal and amplitude signal) extracted by the directional coupler 103, and is used for the traveling wave BPF 104a. And the reflected wave BPF 104b, the traveling wave distributor 105a, and the reflected wave distributor 105b are multiplied by the corresponding signals. The LPF 107 is for blocking high-frequency components of the output signal from the arithmetic unit 106.

  The phase change detection unit 108 detects a change in the phase difference between the traveling wave power signal Pf and the reflected wave power signal Pr based on the output signal from the LPF 107, and will be described later in the power receiving side resonator 200 (described later). This is for determining the presence or absence of the load 3 to be connected (via the link coil L21).

  The amplitude detection circuit 109 is a traveling wave power signal Pf (phase signal and amplitude signal) and a reflected wave power signal Pr (phase signal and amplitude signal) extracted by the directional coupler 103, and is used for the traveling wave. This is to detect the amplitude difference between the signals that have passed through the BPF 104a and the reflected wave BPF 104b.

  The smoothing capacitor C11 is for smoothing the traveling wave power signal Pf which is an output signal from the directional coupler 103. The link coil L11 is an impedance that converts a constant current that is an output from the directional coupler 103 via the smoothing capacitor C11 or a constant current of the DC power source Vcc that passes through the impedance variable element L12 and the detection unit 110 into a constant voltage. It is for performing conversion. Furthermore, the variable impedance element L12 is constituted by, for example, a choke coil connected to the link coil L11, and has a low impedance for direct current and a high impedance for high frequency.

  The state detection unit 110 detects a normal state in which the link coil L11 is not disconnected and connected when a direct current flows from the DC power source Vcc to the link coil L11 via the variable impedance element L12. The relay 110a and the switch 110b are used.

  The control unit 111 includes a timer 111a for measuring a predetermined time T after determining the presence or absence of the load 3 based on the detection result of the phase change detection unit 108, and the timer 111a measures the time. The amplification gain of the power amplification unit 102 is varied within a predetermined time T, and the amplification gain of the power amplification unit 102 is varied so that the amplitude difference between the traveling wave power signal Pf and the reflected wave power signal Pr is constant. Furthermore, when the state detection unit 110 detects a normal state, the power amplification unit 102 is controlled to execute power transmission from the oscillator 101 to the directional coupler 103.

  Note that the configuration of the power transmission device 1 is not limited to the mode provided in the control unit 111, and the timer 111 a may be provided separately from the control unit 111 and controlled by the control unit 111. Good.

  Next, in describing the configuration of the power receiving device 2, the power receiving device 1 includes a power receiving side resonator 200 and a (power receiving side) link coil L21.

  In the power receiving device 2, the power receiving-side oscillator 200 includes a pickup coil L20 having a condition of a parallel resonance frequency f2 and a resonance capacitor C20, which are connected in parallel. The pickup coil L20 uses electromagnetic induction. The current is taken out in a non-contact manner, and the current is amplified and controlled to a constant current.

  The link coil L <b> 21 performs impedance conversion for converting a constant current, which is an output from the power receiving-side oscillator 200, into a constant voltage, and supplies power to the load 3.

  In the non-contact power feeding apparatus according to the embodiment of the present invention configured as described above, a specific operation will be described below.

  When the non-contact power feeding device shown in FIG. 1 is in a standby operation, the directional coupler 103 of the power transmission device 1 generates traveling wave power that is generated by the oscillator 101 and propagates in the forward direction via the power amplifier 102. The phase signal shown in the equation (3) of the signal Pf and the phase signal shown in the equation (4) of the reflected wave power signal Pr propagated in the opposite direction to the traveling wave power signal Pf are taken out at the same time, and the traveling wave BPF 104a And the reflected wave BPF 104b. Here, “A” and “B” shown in the equations (3) and (4) are amplitude values, and are shown in the equations (3) and (4) and equations (5) and (6) described later. “ω” is an angular frequency, and “Δ (delta) t” is a phase shift.

  The traveling wave BPF 104a blocks a frequency component other than the frequency oscillated by the oscillator 101 from the traveling wave power signal Pf from the directional coupler 103, for example, a frequency component other than the fundamental frequency of 10 MHz, The signals are sent to the calculation unit 106 and the amplitude difference detection unit 109 via the traveling wave distributor 105a. On the other hand, the reflected wave BPF 104b blocks, for example, the frequency components other than 10 MHz, which is the fundamental wave, similar to the above described that the oscillator 101 oscillates, among the frequency components of the reflected wave power signal Pr from the directional coupler 103, The signals are sent to the calculation unit 106 and the amplitude difference detection unit 109 via the reflected wave distributor 105b.

  The arithmetic unit 106 multiplies the traveling wave power signal Pf from the directional coupler 103 via the traveling wave BPF 104a and the reflected wave power signal Pr from the directional coupler 103 via the reflected wave BPF 104b. Thus, the output signal S1 shown in the equation (5) is generated. Here, “C” shown in Expression (5) is “AB / 2”.

  The LPF 107 cuts off the high-frequency component of the output signal S1 from the calculation unit 106 and generates the output signal S2 shown in Expression (6), thereby obtaining the signal proportional to the reflected wave power signal Pr.

  For example, the phase change detection unit 108 performs a differential operation on the temporal change of the output signal S2 from the LPF 107, and the frequency component other than the frequency at which the oscillator 101 oscillates via the traveling wave BPF 104a and the reflected wave BPF 104b. For example, since the frequency components other than the fundamental wave of 10 MHz are blocked, the phase difference between the traveling wave power signal Pf and the reflected wave power signal Pr is detected only with the fundamental frequency for power transmission, that is, the angular frequency ω. For example, when the load 3 fluctuates, erroneous phase detection due to frequency generation other than the frequency at which the oscillator 101 oscillates is generated so that harmonics and spurious components are generated in the traveling wave power signal Pf from the power amplifier 102. If the reflected wave changes as a result of the detection, the power receiving side resonator 200 of the power receiving device 2 is detected. (Via the link coil L21) determines that the load 3 is connected, and sends the detection data S3 to that effect to the control unit 111.

  The control unit 111 detects the reception of the detection data S3 from the phase change detection unit 108 and activates the time measuring function of the timer 111a, and operates for a predetermined time T, for example, when the load 3 is not driven or driven. The time T required for charging the power supply is started, and the amplification gain of the power amplifying unit 102 can be controlled, for example, maximized within the time T, and when the time up is detected, the amplification gain is waited. Return to a predetermined level of state.

  Here, the amplitude difference detection circuit 109 transmits the traveling wave BPF 104a and the traveling wave distribution from the directional coupler 103 within a predetermined time T during the gain control to the power amplification unit 102 by the control unit 111 as described above. Of the traveling wave power signal Pf transmitted sequentially through the coupler 105a and the amplitude of the reflected wave power signal Pr transmitted from the directional coupler 103 via the reflected wave BPF 104b and the reflected wave distributor 105b. The difference is detected, and detection data S4 to that effect is sent to the control unit 111.

  The control unit 111 receives the detection data S4 from the amplitude difference detection unit 109, and the amplification gain of the power amplification unit 102 so that the difference value between the traveling wave power signal Pf and the reflected wave power signal Pr is constant. Can be varied. As a result, even when the state of power transmission to the load 3 is continuing, even if the load changes its state due to a charging operation or the like, the execution power due to power transmission to the load 3 is not reduced and is secured at a constant power value. Will be.

  According to the operations described above, power amplification caused by fluctuations in the load 3 from the no-load state during standby operation without requiring the power energy on the power receiving side supplied in a non-contact manner from the power transmitting device 1 to the power receiving device 2 Whether or not the load 3 is connected to the power receiving resonator 200 of the power receiving device 2 (via the link coil L21) in the phase difference detection circuit 108 that prevents erroneous detection due to harmonics and spurious components from the unit 102. In addition, even if the state of power transmission to the load 3 continues and the state of the load fluctuates due to a charging operation or the like, the execution power due to power transmission to the load 3 does not decrease and is constant. This state is maintained even when the link coil L11 is in an abnormal state such as disconnection or disconnection.

  Therefore, according to the state detection unit 100 of the power transmission device 1, when the link coil L11 is in a normal state where the link coil L11 is not disconnected, the direct current from the direct current power source Vcc is transmitted via the impedance variable element L12. Since it flows to L11, the relay 110a is driven, and the switch 110b is switched from the off state to the on state. Upon detecting this, the control unit 111 controls the power amplification unit 102 to execute power transmission from the oscillator 101 to the directional coupler 103, that is, permits transmission of the traveling wave power signal Pr. Since power transmission is not executed in an abnormal state where L11 is disconnected or disconnected, it is possible to easily prevent, for example, a failure in the short mode caused by the power transmission.

  The contactless power supply device according to the present invention has been described with a specific embodiment. However, the present invention is not limited to this embodiment, and any configuration known so far can be used as long as the effect of the present invention is achieved. It goes without saying that even devices can be employed.

DESCRIPTION OF SYMBOLS 1 ... Power transmission apparatus 100 ... Power transmission side resonator f1 ... Parallel resonance frequency (of power transmission side resonator) 101 ... Oscillator 102 ... Power amplification part 103 ... Directional coupler 104a ... Traveling wave BPF ( Pand pass filter)
104b …… BPF for reflected wave (Pand pass filter)
106 …… Calculation unit 108 …… Phase change detection unit 109 …… Amplitude difference detection unit 110 …… State detection unit 111 …… Control unit 111a …… Timer L11 …… Link coil L12 …… Impedance variable element 2 …… Power receiving device 200 …… Receiving side resonator f2 …… Parallel resonance frequency (of receiving side resonator) 3 …… Load Pf …… Progressive wave power signal Pr …… Reflected wave power signal

Claims (6)

Occurs between the power transmission side resonator (100) of the power transmission device (1) and the power reception side resonator (200) of the power reception device (2) each having a predetermined parallel resonance frequency (f1, f2) in the near electromagnetic field. A non-contact power feeding device that supplies electric power generated by the power transmission device to the power receiving device in a non-contact manner by magnetic field coupling,
The power transmission device includes an oscillator (101) for generating a traveling wave power signal (Pf) propagating in a forward direction, and a power amplifying unit (102) for amplifying the traveling wave power signal generated by the oscillator. ), The traveling wave power signal from the power amplifying unit and the reflected wave power signal (Pr) propagating in the opposite direction, and the directional coupler (103) A computing unit (106) for multiplying the traveling wave power signal and the reflected wave power signal, and a change in phase difference between the traveling wave power signal and the reflected wave power signal based on a computation result of the computing unit. And a phase change detection unit (108) for determining whether or not there is a load (3) connected to the power receiving resonator of the power receiving device.   The non-contact power feeding device according to claim 1, wherein the power transmission device includes band-pass filters (104 a, 104 b) for cutting off frequency components other than the frequency oscillated by the oscillator.   The power transmission device counts a predetermined time (T) after determining the presence or absence of the load based on the detection result of the phase change detection unit, and is timed by the timer. The contactless power feeding device according to claim 1, further comprising a control unit (111) for changing an amplification gain of the power amplification unit within the predetermined time.   The power transmission device includes: an amplitude difference detection circuit (109) for detecting an amplitude difference between the traveling wave power signal and the reflected wave power signal; and an amplification gain of the power amplification unit so that the amplitude difference is constant. The non-contact electric power feeder according to claim 1, further comprising a control unit (111) for changing. The directional coupler is coupled to the power transmission side resonator via a link coil (L11) for impedance conversion,
The power transmission device includes a variable impedance element (L12) that is connected to the link coil and has a low impedance for DC and a high impedance for high frequency, and a direct current flows through the link coil via the impedance element. The non-contact power feeding apparatus according to claim 1, further comprising a state detection unit (110) that detects a normal state that the link coil is not disconnected and connected.   The power transmission device includes a state control unit (111) for controlling the power amplification unit to execute power transmission from the oscillator to the directional coupler when the detection unit detects a normal state. 6. The non-contact power feeding device according to claim 5, wherein

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