JP2015002598A - Non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and compact non-contact power transmission device, capable of stable power transmission by controlling a voltage to be applied to a load to a predetermined value, and capable of stable power transmission to a variety of loads.SOLUTION: A non-contact power transmission device includes reactive power generation means for generating a reactive power connected in parallel to power reception means and an AC load. The reactive power generation means controls a magnitude of the reactive power in such a manner that an effective value of an AC voltage to be applied to the AC load becomes a predetermined value.

Description

  The present invention relates to a non-contact power transmission apparatus that transmits electric power in a non-contact manner using an electromagnetic induction phenomenon or an electrostatic induction phenomenon.

  Conventionally, a non-contact power transmission apparatus that transmits power in a non-contact manner using an electromagnetic induction phenomenon or an electrostatic induction phenomenon has been proposed. The non-contact power transmission apparatus shown in FIG. 5 is a general configuration diagram of a non-contact power transmission apparatus using electromagnetic induction. The conventional non-contact power transmission device 3 of FIG. 5 includes an AC power source 100, a power feeding coil 210, a power receiving coil 220, and an AC load 300. In the non-contact power transmission device 3, the feeding coil 210 generates a magnetic field according to the output of the AC power supply 100, and an electromotive force is generated in the receiving coil 220 by electromagnetic induction from the magnetic field generated by the feeding coil 210. The AC load 300 consumes the electric power obtained by induction. That is, the power of the AC power supply 100 is supplied to the AC load 300 by electromagnetic induction between the power supply coil 210 and the power reception coil 220 that are magnetically coupled.

  In the conventional non-contact power transmission device, the distance between the feeding coil 210 and the power receiving coil 220 may change, or the impedance of the AC load 300 may change, and stable power transmission may be difficult. For this reason, for example, as shown in Patent Document 1 and Patent Document 2, a variable impedance that can be controlled is inserted between the power receiving coil and the AC load, and the value of the variable impedance is adjusted to obtain stable power. It can be transmitted.

  In patent document 1, in order to transmit stable electric power, the method by which a control apparatus changes the impedance of the variable capacitor inserted between the receiving coil and the load is proposed, and it is mechanical like a motor. The impedance of the variable capacitor is changed by the driving means.

  Patent Document 2 proposes a method for adjusting the impedance of a load.

JP 2010-141977 A JP 2012-182980 A

  However, in the non-contact power transmission apparatus as disclosed in Patent Document 1, in order to change the impedance of the variable capacitor, a mechanical driving means such as a motor is generally required, which is large and expensive. There is a problem of cost. Moreover, in the non-contact power transmission apparatus as shown in Patent Document 2, since the impedance of a normal load is determined in advance by the characteristics of the load and cannot be arbitrarily adjusted, a system to which this load impedance adjusting method can be applied There is a problem that there are very few in practical use.

  The present invention has been made in view of such circumstances, and can control the voltage applied to the load to a predetermined value to realize stable power transmission. An object of the present invention is to provide an inexpensive and small non-contact power transmission device capable of stable power transmission.

  The non-contact power transmission apparatus according to claim 1 includes a reactive power generation unit that is provided in parallel with the power reception unit and the AC load, and generates reactive power, and the reactive power generation unit is configured to determine an effective AC voltage applied to the AC load. The magnitude of reactive power is controlled so that the value becomes a predetermined value.

  The non-contact power transmission apparatus according to claim 2 is provided between the power receiving means and the rectifying means, and includes a reactive power generating means for generating reactive power, and an effective value of the AC voltage on the AC side of the rectifying means is a predetermined value. The reactive power magnitude is controlled so as to be a value.

  According to the present invention, the reactive power generator is connected to the power receiving means, and the reactive power generated by the reactive power generator is adjusted so that the voltage applied to the load is controlled to a predetermined value and stable power transmission is possible. In addition, a non-contact power transmission device that can stably transmit power to various loads can be made inexpensive and small.

It is a block diagram which shows an example of a structure of the non-contact electric power transmission apparatus which concerns on this invention. It is a block diagram which shows the reactive power generator in the 1st Example of the non-contact electric power transmission apparatus which concerns on this invention. It is a block diagram which shows the reactive power generator in the 2nd Example of the non-contact electric power transmission apparatus which concerns on this invention. It is a block diagram which shows the structure of the 3rd Example of the non-contact electric power transmission apparatus which concerns on this invention. It is a block diagram which shows the structure of the conventional non-contact electric power transmission apparatus.

  The non-contact power transmission device 1 according to the present invention shown in FIG. 1 transmits power from the feeding coil 210 in a non-contact manner due to an electromagnetic induction phenomenon between the feeding coil 210 as the feeding means and the receiving coil 220 as the power receiving means. The AC power thus transmitted is transmitted to the AC load 300 connected to the power receiving coil. When electric power is transmitted in a non-contact manner by the electrostatic induction phenomenon, a power feeding electrode is used as the power feeding means, and a power receiving electrode is used as the power receiving means. In the following description, the case of the electromagnetic induction phenomenon using the feeding coil 210 and the power receiving coil 220 will be described. However, the operation of the reactive power generating means is the same as that of the electromagnetic induction phenomenon even when the electrostatic induction phenomenon is used. Is omitted.

  The non-contact power transmission device 1 includes an AC power supply 100, a power feeding coil 210, a power receiving coil 220, a reactive power generation device 400 (401), and an AC load 300. The feeding coil 210 generates a magnetic field according to the output of the AC power supply 100, and an electromotive force is generated by electromagnetic induction from the magnetic field generated by the feeding coil 210 in the power receiving coil 220, and the power is transmitted to the AC load 300. The

  The AC power source 100 is a power source that operates as a voltage source that generates an AC voltage. The voltage and frequency of the AC power supply 100 are appropriately selected so as to obtain desired power transmission characteristics in accordance with the overall configuration of the non-contact power transmission device 1, and the voltage waveform includes an arbitrary number of harmonic components other than a sine wave. For example, a rectangular wave may be used.

  Here, reactive power generator 400 (401) is connected in parallel to power receiving coil 220 and AC load 300. The reactive power generation device 400 (401) is reactive power generation means for generating reactive power, and controls the magnitude of reactive power so that the effective value of the AC voltage applied to the AC load 300 becomes a predetermined value. To do. The reactive power generators 400 and 401 have various forms, and will be specifically described below in the examples.

  FIG. 2 is a configuration diagram showing the reactive power generation device in the first embodiment of the contactless power transmission device according to the present invention. The reactive power generation device 400 includes transistors, IGBTs, and the like, and includes semiconductor switching devices 411 and 412, capacitors 421 and 422, a reactor 430, a power reception voltage sensor 440 that detects a power reception voltage received by the power reception coil 220, and a phase of the power reception voltage. Received voltage phase detection circuit 492 to detect, gate command generation circuit 480 to generate a gate command for turning on / off the semiconductor switching devices 411 and 412, and set and instructed as an electrical signal in consideration of the phase of the received voltage As an electric signal, a reactive power control circuit 460 that outputs a reactive power command to the gate command generation circuit 480 so that a deviation between a received voltage command that is a target value of the received voltage and a received voltage detected by the received voltage sensor 440 becomes zero. Capacitors 421 and 422 that are preset and indicated An active power control circuit 470 that outputs an active power command to the gate command generation circuit 480 so that the deviation between the DC voltage command that is the target value of the DC voltage and the DC voltage detected by the DC voltage sensor 450 becomes zero. Yes.

  Next, the operation of the non-contact power transmission device 1 including the reactive power generation device 400 will be described. A magnetic field is generated in the feeding coil 210 according to the voltage generated by the AC power supply 100, and a voltage (electromotive force) is generated in the receiving coil 220 in response to the magnetic field. The voltage generated by the power receiving coil 220 changes according to the distance between the power feeding coil 210 and the power receiving coil 220 and the impedance of the AC load 300 even when the voltage of the AC power supply 100 is constant. The power reception voltage is controlled to a predetermined value by adjusting the reactive power generated by 400.

  Next, the operation of the reactive power generation device 400 will be described. The reactive power generation device 400 outputs an arbitrary voltage Va by turning on / off the semiconductor switching device 411 and the semiconductor switching device 412 by pulse width modulation or the like. More specifically, the reactive power control circuit 460 considers the phase of the received voltage detected by the received voltage phase detection circuit 492, and the voltage Vr of the receiving coil 220 detected by the received voltage sensor 440 and a predetermined received voltage command. The reactive power control amount is output to the gate command generation circuit 480 so that the deviation from (target voltage) becomes zero.

  In addition, the active power control circuit 470 has effective power so that the deviation between the voltage across the capacitor 421 and the capacitor 422 connected in series detected by the DC voltage sensor 450 and a predetermined DC voltage command (target voltage) becomes zero. The control amount is output to the gate command generation circuit 480.

  In the gate command generation circuit 480, a gate for turning on / off the semiconductor switching devices 411 and 412 according to the reactive power control amount output from the reactive power control circuit 460 and the active power control amount output from the active power control circuit 470. The command is output by pulse width modulation. Here, in the first embodiment, the switching frequency (modulation frequency) of the gate command is assumed to be several tens of times the frequency of the AC power supply 100. For example, if the frequency of the AC power supply 100 is 20 kHz, the reactive power generation device The switching frequency of 400 is about 500 kHz or more.

  Here, the voltages of the capacitors 421 and 422 change with the input / output of the active power, but the input / output of the active power is zero when the voltage is constant in the steady state. The active power control circuit 470 operates so as to maintain a necessary voltage by suppressing fluctuations in DC voltage due to transient active power input / output when the distance between the power feeding coil 210 and the power receiving coil 220 or load impedance changes. become.

  In this way, the received voltage can be controlled by changing the reactive power generated by the reactive power generation device 400. When this control flow is shown, first, when the distance between the power feeding coil 210 and the power receiving coil 220 is increased, the mutual inductance between the power feeding coil 210 and the power receiving coil 220 is reduced, and the AC power supply 100 supplies a constant voltage. However, the voltage on the load (power receiving) side is lowered because the magnetic resistance between the power feeding coil 210 and the power receiving coil 220 is increased and the magnetic flux reaching the power receiving coil 220 is decreased.

  At this time, since the energy transmitted through the magnetic circuit (transmission space) is the product of the magnetic flux and the magnetic field strength, the magnetic field strength is increased so as to compensate for the decrease in the magnetic flux, the transmission energy is maintained, and the received voltage is controlled to a predetermined value. can do. The magnetic field intensity can be controlled by adjusting the reactive power supplied from the power receiving side, and accordingly, the received voltage can be controlled by changing the reactive power generated by the reactive power generator 400.

  As described above, according to the contactless power transmission device 1 of the first embodiment, the reactive power generation device 400 that is the reactive power generation unit is connected to the power receiving coil 220 that is the power reception unit, and the reactive power generation device 400 generates the invalidity. By adjusting the power, the voltage applied to the AC load 300 (load) can be controlled to a predetermined value to realize stable power transmission, and stable power transmission can be achieved for various loads. The possible contactless power transmission device 1 can be made inexpensive and small.

  In the first embodiment, an example in which the reactive power generation device 400 is configured by a voltage type inverter has been described. However, a current type inverter or an analog amplifier may be used, and the same effect can be obtained if reactive power is generated on the power receiving side. Is obtained.

  In the first embodiment, the switching frequency of the reactive power generation device 400 is several tens of times the frequency of the AC power supply 100. However, in the second embodiment, the switching frequency of the reactive power generation device 401 is matched with the frequency of the AC power supply. The case will be described. FIG. 3 is a configuration diagram showing a reactive power generation device in a second embodiment of the non-contact power transmission device according to the present invention.

  In FIG. 3, the reactive power generation device 401 is the same as that of the first embodiment because the semiconductor switching devices 411 and 412, the capacitors 421 and 422, the reactor 430, the power reception voltage sensor 440 and the DC voltage sensor 450 are omitted. However, the control circuit portion from receiving the outputs of the power reception voltage sensor 440 and the DC voltage sensor 450 to generating the gate commands for the semiconductor switching devices 411 and 412 is different from that of the first embodiment.

  In FIG. 3, the control circuit portion until the gate command of the semiconductor switching devices 411 and 412 is generated is a power reception voltage effective value calculation circuit 491 that calculates an effective value of the power reception voltage detected by the power reception voltage sensor 440, and an electric signal in advance. Reactive power control circuit 461 that generates a DC voltage command so that the deviation between the received voltage command, which is a target value of the received voltage that is set and instructed, and the received voltage effective value calculation circuit 491 is zero. The active power control circuit 471 that generates the phase shift command so that the deviation between the DC voltage command generated by the reactive power control circuit 461 and the DC voltage detected by the DC voltage sensor 450 is zero, and the received voltage sensor 440 detects Power reception voltage phase detection circuit 492 that detects the phase of the power reception voltage, and the power reception voltage level detected by the power reception voltage phase detection circuit 492 A gate command generation circuit 481 that outputs to the semiconductor switching devices 411 and 412, as a gate command, a pulse signal having a duty ratio of 50% having the same frequency as the received voltage at a phase shifted by the phase shift command output from the active power control circuit 471. It consists of

  By using the reactive power generation device 401 having such a configuration, the output voltage Va of the inverter when the semiconductor switching devices 411 and 412 are turned on / off becomes a rectangular wave having the same frequency as the received voltage. The phase of the output voltage Va is determined by the active power control circuit 471 as a shift amount (phase difference) from the phase of the received voltage, and the amplitude of the output voltage Va is determined by the DC voltage. The amount of reactive power generated can be adjusted by the amplitude of the output voltage Va, that is, the DC voltage, and the amount of active power generated can be adjusted by the phase difference between the output voltage Va and the received voltage Vr. By adjusting the reactive power generated by the device 401, the received voltage can be controlled to a predetermined value.

  In the reactive power generation device 401 according to the second embodiment, in addition to the effects of the first embodiment, the switching frequency of the reactive power generation device 401 is made to coincide with the frequency of the AC power supply so that the switching frequency is lower than that in the first embodiment. Thus, it is possible to employ an inexpensive semiconductor switching device that reduces energy loss due to switching and has a slow switching operation.

  In the first embodiment and the second embodiment, the case of the AC load 300 has been described. In the third embodiment, when the load is a DC load such as a storage battery or LED lighting, the AC power received by the reactive power generator 402 is received. A non-contact power transmission device 2 that supplies power to a DC load while converting (rectifying) the power into DC power will be described. In other words, the reactive power generating device 402 according to the third embodiment is provided with a reactive power generating unit that generates reactive power between the power receiving unit and the rectifying unit. In addition, since the direct current load is the storage battery 301, it is provided with a charging function. FIG. 4 is a block diagram showing the configuration of the third embodiment of the non-contact power transmission apparatus according to the present invention.

  The reactive power generator 402 in the non-contact power transmission apparatus 2 of FIG. 4 is a reactive power generator that converts the AC power received by the power receiving coil 220 into DC power to charge the storage battery 301 and generates reactive power. . The reactive power generation device 402 is different from the reactive power generation device 400 of the first embodiment in that a current sensor 451 is added between the capacitor 421 and the storage battery 301 as a load, and the active power control circuit 472 is a storage battery. The difference is that a function of controlling the charging current 301 is provided.

  The operation of the active power control circuit 472 of the reactive power generation device 402 is such that the voltage of the storage battery 301 detected by the DC voltage sensor 450 does not exceed the charging voltage command that is preset and instructed as an electrical signal, and the current sensor 451 The active power control amount that maximizes the charging power is output to the gate command generation circuit 482 so that the detected current of the storage battery 301 does not exceed the charging current command that is preset and instructed as an electrical signal.

  The reactive power generation device 402 operates in this manner, so that in addition to the effects of the first embodiment, the power reception voltage can be controlled to a predetermined value while charging the storage battery 301, and the contactless power transmission device is highly efficient. Can be obtained. In addition, although charging of the storage battery 301 was demonstrated as an example as DC load, the same effect is acquired even if DC load is other DC loads, such as LED lighting.

  As described above, according to the present invention, stable power transmission can be realized by controlling the voltage applied to the load to a predetermined value, and stable power transmission to various loads. A non-contact power transmission device that is possible, inexpensive, and small can be provided.

DESCRIPTION OF SYMBOLS 1 ... Non-contact power transmission device 2 ... Non-contact power transmission device 3 ... Non-contact power transmission device 100 ... AC power supply 210 ... Feeding coil 220 ... Power reception Coil 300 ... AC load 301 ... Storage battery 400 ... Reactive power generator 401 ... Reactive power generator 402 ... Reactive power generator 411 ... Semiconductor switching device 412 ... Semiconductor switching device 421: Capacitor 422 ... Capacitor 430 ... Reactor 440 ... Receiving voltage sensor 450 ... DC voltage sensor 451 ... Current sensor 460 ... Reactive power control circuit 461 ... Reactive power control Circuit 462 ... reactive power control circuit 470 ... active power control circuit 471 ... active power control circuit 472 ... active power control circuit 480 · Gate command generation circuit 481 ... gate command generation circuit 482 ... gate command generation circuit 491 ... receiving voltage effective value calculation circuit 492 ... receiving voltage phase detecting circuit

Claims (2)

Non-contact power transmission for transmitting AC power sent from the power feeding means to an AC load connected to the power receiving means in a non-contact manner by an electromagnetic induction phenomenon or electrostatic induction phenomenon between the power feeding means and the power receiving means. In the device
Reactive power generating means that is provided in parallel with the power receiving means and the AC load and generates reactive power,
The non-contact power transmission device, wherein the reactive power generation means controls the magnitude of the reactive power so that an effective value of an AC voltage applied to the AC load becomes a predetermined value. Due to the electromagnetic induction phenomenon or electrostatic induction phenomenon between the power feeding means and the power receiving means, the AC power sent from the power feeding means is connected to the power receiving means through a rectifying means that converts AC power sent from the power feeding means into DC power. In a non-contact power transmission device that transmits to a dc load,
Reactive power generating means for generating reactive power provided between the power receiving means and the rectifying means,
A non-contact power transmission apparatus that controls the magnitude of the reactive power so that the effective value of the AC voltage on the AC side of the rectifying means becomes a predetermined value.

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