JP5927583B2 - Contactless power supply system - Google Patents

Description

  The present invention relates to a non-contact power feeding system.

  2. Description of the Related Art Conventionally, a non-contact power feeding device that supplies power in a non-contact manner to a self-propelled mobile body has been provided (see, for example, Patent Document 1). This non-contact power feeding device is connected to the DC power supply circuit that converts the AC output of the AC power supply into a DC output of a constant voltage, the inverter that converts the DC output of the DC power supply circuit to the AC output of a predetermined frequency, and the output side of the inverter And a power supply line to which AC power of a predetermined frequency is applied from the inverter, and a capacitor that is connected in series to the power supply line and forms a resonance circuit together with the power supply line. In this non-contact power supply device, the effective power given to the power supply line can be increased while reducing the reactance component connected to the output unit of the inverter by the resonance circuit including the power supply line and the capacitor. That is, the power factor reduction due to the reactance of the feeder line can be compensated for by the above-described resonance circuit.

JP-A-10-174206

  In the non-contact power feeding device shown in the above-mentioned Patent Document 1, although the power factor decrease due to the reactance of the feed line can be compensated for by the above-described resonance circuit, the reactance component changes depending on the line length and load of the feed line. Accordingly, the capacity of the capacitor had to be changed, and it was necessary to replace the capacitor.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a non-contact power feeding system with improved workability of resonance adjustment of a resonance circuit.

  The non-contact power feeding system of the present invention includes a high-frequency power source and a power feeding unit provided with a power feeding line connected in series to the high-frequency power source, and a non-contact arrangement with respect to the power feeding line, which is caused by electromagnetic induction with the feeding line. A power receiving unit that uses the power as the power supplied to the load. The high-frequency power source includes a capacitive reactance that forms a resonance circuit together with the inductance of the feeder line, and a control unit that controls the operation of the capacitive reactance. The capacitive reactance has a bridge circuit composed of four semiconductor elements that do not have reverse blocking capability, and a capacitor that is connected between the midpoints of the bridge circuit and accumulates snubber energy when current is interrupted. Then, the control unit controls the pair of semiconductor elements located on the diagonal among the four semiconductor elements so that the on / off operations are simultaneously performed, and when one pair is on, the other pair is Control to turn off.

  In this non-contact power supply system, the control unit automatically adjusts the resonance of the resonance circuit by adjusting the on / off switching timing of the four semiconductor elements to change the apparent capacitance of the capacitor. It is also preferable to have a function.

  In this non-contact power supply system, it is also preferable that the control unit adjusts the resonance of the resonance circuit at any time by the automatic resonance adjustment function while the system is operating.

  In this contactless power supply system, it is also preferable that the control unit increases the impedance of the resonance circuit by shifting the resonance circuit from resonance when the load of the power reception unit falls below a predetermined fluctuation range.

  In this non-contact power supply system, it is also preferable that the control unit determines whether or not the resonance circuit is in a resonance state based on the output voltage value of the high frequency power supply with no load.

  In this non-contact power supply system, it is also preferable that the control unit determines whether or not the resonance circuit is in a resonance state based on a ripple current of the high-frequency power supply with no load.

  There is an effect that it is possible to provide a non-contact power supply system in which the workability of resonance adjustment of the resonance circuit is improved.

The electric power feeding part of the non-contact electric power feeding system of this embodiment is shown, (a) is the block diagram, (b) is a circuit diagram of the capacitor | condenser part which is the principal part. It is a system block diagram same as the above. (A)-(f) is explanatory drawing explaining operation | movement of the capacitor | condenser part which is a principal part same as the above. It is a current waveform figure at the time of resonance adjustment same as the above.

  Hereinafter, an embodiment of a non-contact power feeding system will be described with reference to the drawings.

  FIG. 2 is a system configuration diagram of the contactless power supply system according to the present embodiment. This contactless power supply system includes a power supply unit 1 and a power reception unit 2 as main components, for example, a motor 3 of an automatic guided vehicle that is a load. In contrast, power is supplied. The load is not limited to the motor 3 and may be other.

  The power supply unit 1 is connected to the high frequency power supply 10 in series to generate a high frequency (for example, 40 kHz) sinusoidal AC voltage from the AC voltage of the commercial power supply 4, and is supplied with the high frequency output of the high frequency power supply 10. And an electric wire 11. The feeder 11 has a length of several tens to several hundreds of meters, has a large inductance component, and is an LR load. In the present embodiment, the return lines of the feeder line 11 are arranged in parallel to cancel the magnetic fields generated from each other (see FIG. 2).

  FIG. 1A is a block diagram of the power feeding unit 1. The high-frequency power source 10 includes an output unit 10d that outputs high-frequency AC power to the power supply line 11, an output current control unit 10b that controls the output current of the output unit 10d, and a capacitor unit that forms a resonance circuit together with the power supply line 11. 10e, a resonance adjustment control unit 10c that controls the operation of the capacitor unit 10e, and a power supply control unit 10a that performs general control. FIG. 1B is a circuit diagram of the capacitor unit 10e. The capacitor unit 10e is provided to compensate for a power factor decrease due to reactance of the feeder line 11. A capacitor C2 is connected between the output end of the capacitor unit 10e and one end of the feeder line 11. In this embodiment, the capacitor C1 and the capacitor C2 of the capacitor unit 10e constitute a resonance capacitor. The

  As shown in FIG. 1 (b), the capacitor unit 10e is connected between a bridge circuit composed of four IGBTs 12a to 12d (semiconductor elements) having no reverse blocking capability and a midpoint of the bridge circuit to cut off the current. It is comprised with the capacitor | condenser C1 which accumulate | stores snubber energy. Each of the IGBTs 12a to 12d is a forward / reverse bidirectional conduction type element that is configured by a diode connected in parallel with the element in the opposite direction, and that allows current to flow in both directions (forward and reverse directions). And this capacitor | condenser part 10e is connected in series with the feeder 11 and the capacitor | condenser C2, as shown to Fig.1 (a), and comprises a resonance circuit with the feeder 11 and the capacitor | condenser C2. Although not shown, the gate terminals of the IGBTs 12a to 12d are connected to the resonance adjustment control unit 10c, and the IGBTs 12a to 12d are turned on / off according to a control signal from the resonance adjustment control unit 10c. Is done. In this embodiment, a capacitive reactance is configured by the capacitor unit 10e and the capacitor C2, and a control unit is configured by the resonance adjustment control unit 10c.

  As shown in FIG. 2, the power receiving unit 2 includes a pickup 20 in which a winding is wound around a U-shaped core disposed so as to sandwich the power supply line 11, and a space between the pickup 20 and the power supply line 11. A resonance circuit 21 for increasing the electromotive force generated in the winding by electromagnetic induction and a constant voltage circuit 22 for stabilizing the output of the resonance circuit 21 are provided. And the electric power stabilized by the constant voltage circuit 22 is supplied to the motor 3 which is a load. The pickup 20 is movable in a direction parallel to the power feeding unit 11 (in the direction of arrows AB in FIG. 2) as the motor 3 operates.

  Next, the operation of the capacitor unit 10e will be described with reference to FIGS. 3 (a) to 3 (f). FIG. 3A shows a state in which the load current is inverted after the capacitor C1 is charged, and the charge charged in the capacitor C1 is discharged before the inversion. At this time, since the pair of IGBTs 12b and 12c is turned on, the capacitor C1 is discharged along the path of IGBT 12b → capacitor C1 → IGBT 12c (the path of arrows a1 and a2 in FIG. 3A). When the discharge of the capacitor C1 is completed, the current stops flowing to the capacitor C1, and the diode 12 → IGBT 12c path (the path indicated by the arrow a3 in FIG. 3B) and the IGBT 12b → IGBT 12d diode path (FIG. 3 (3)). b) in the path indicated by arrow a4 in FIG. When the pair of diagonal IGBTs 12b and 12c is turned off in this state and the pair of IGBTs 12a and 12d is turned on, the diode path of the IGBT 12a → the capacitor C1 → the diode of the IGBT 12d (in FIG. 3C). The path of the arrows a5 and a6) of the capacitor C1 is charged.

  When the load current is eventually reversed, as shown in FIG. 3 (d), the capacitor C1 is discharged along the path of IGBT 12d → capacitor C1 → IGBT 12a (paths of arrows a7 and a8 in FIG. 3 (d)). When the discharge of the capacitor C1 is completed, no current flows through the capacitor C1, and the diode 12 → IGBT 12a path (the path indicated by the arrow a9 in FIG. 3E) and the IGBT 12d → IGBT 12b diode path (FIG. 3 (3)). e) each is bypassed to a path indicated by an arrow a10), and a current flows through each path. In this state, when the pair of IGBTs 12a and 12d is turned off and the pair of IGBTs 12b and 12c is turned on, the diode path of the IGBT 12c → the capacitor C1 → the diode 12b of the IGBT 12b (arrows a11, The capacitor C1 is charged in the path a12). By repeating the above operation and performing phase control, the capacitor C1 can be used as a variable capacitor for resonance adjustment. Here, when all the IGBTs 12a to 12d are turned off at the same time, no current flows to the capacitor unit 10e. Therefore, when the pair of IGBTs 12a and 12d is turned on, the pair of IGBTs 12b and 12c is turned off at the same time. When the pair is turned off, the pair of IGBTs 12b and 12c are turned on simultaneously.

  Here, the capacitor unit 10e of the present embodiment can change the apparent capacitor capacity depending on how much the on / off switching timing of each of the IGBTs 12a to 12d is advanced with respect to the output voltage phase of the output unit 10d. . Since the resonance circuit composed of the feeder line 11, which is an LR load, the capacitor unit 10e, and the capacitor C2 is brought into a resonance state, the power factor decrease due to the reactance of the feeder line 11 can be compensated. Resonance adjustment of the above resonant circuit is necessary. Hereinafter, the resonance adjustment will be described. At the time of resonance adjustment, the motor 3 is not connected to the power receiving unit 2, that is, resonance adjustment is performed with no load.

  The operator estimates the capacitance of the capacitor in which the resonance circuit is in a resonance state from the line length of the feeder line 11 connected to the high frequency power supply 10, and the capacitance estimated by the combined capacitance of the capacitor C1 and the capacitor C2 of the capacitor unit 10e. The capacity of the capacitor C1 is set so as to be larger. Thereafter, the operator turns on the power switch (not shown) to turn on the power, and advances the phase of the capacitor unit 10e while monitoring the output current I1 of the high-frequency power source 10, thereby reducing the apparent capacity of the capacitor C1. Enlarge. At this time, the combined capacitance of the capacitors C1 and C2 is reduced by increasing the apparent capacitance of the capacitor C1. The operator advances the phase of the capacitor unit 10e until the ripple current of the output current I1 falls within a predetermined allowable range d1 (see FIG. 4), and finally resonates by slightly delaying the phase of the capacitor unit 10e. Adjustment is complete.

  Thus, according to the present embodiment, the apparent capacitance of the capacitor C1 can be changed by adjusting the on / off switching timing of the four IGBTs 12a to 12d. Thus, even when the reactance component changes, the apparent capacity can be adjusted without replacing the capacitor, and the workability of resonance adjustment of the resonance circuit can be improved as compared with the conventional example. Further, the resonance circuit can be brought into a resonance state by performing resonance adjustment so that the ripple current of the high frequency power supply 10 is within a predetermined allowable range d1, and as a result, the reactance connected to the output unit of the high frequency power supply 10 It is possible to increase the effective power given to the feeder line 11 while reducing the component.

  In the present embodiment, the operator adjusts the ripple current to fall within a predetermined allowable range d1 while monitoring the output current I1 of the high-frequency power supply 10. For example, the resonance adjustment mode is provided in the high-frequency power supply 10 and this resonance is achieved. When the adjustment mode is set, the above-described resonance adjustment may be automatically performed, whereby the construction time can be shortened and the associated cost reduction can be realized. In addition, the automatic resonance adjustment described above may be performed at any time while the system is in operation, so that the resonance adjustment is performed every time the load changes during the system operation and the reactance changes. Thus, the resonance circuit can be maintained in a resonance state.

  Furthermore, when the load of the power receiving unit 2 falls below a predetermined fluctuation range set in advance, the above resonance circuit may be controlled to shift from resonance. As a result, a drop in impedance can be compensated for, so that an excessive current can be prevented from flowing in the circuit due to the drop in impedance. The predetermined fluctuation range refers to a range that can be normally taken by the load of the power receiving unit 2, and is set according to the load.

  In the present embodiment, the resonance adjustment is performed so that the ripple current of the high-frequency power supply 10 is within the predetermined allowable range d1, but for example, the output voltage V1 (see FIG. 1A) of the high-frequency power supply 10 is set in advance. Resonance adjustment may be performed so that the effective power is applied to the power supply line 11 while reducing the reactance component connected to the output unit of the high-frequency power supply 10. In the present embodiment, the IGBTs 12a to 12d have been described as examples of semiconductor elements having no reverse blocking capability. However, for example, MOSFETs may be used, and the present invention is not limited to this embodiment.

DESCRIPTION OF SYMBOLS 1 Feed part 10 High frequency power supply 11 Feed line 10c Resonance adjustment control part (control part)
10e Capacitor section (capacitive reactance)
12a to 12d IGBT (semiconductor element)
C1 capacitor C2 capacitor (capacitive reactance)

Claims (6)

A power supply unit including a high-frequency power supply and a power supply line connected in series to the high-frequency power supply;
A power receiving unit that is disposed in a non-contact manner with respect to the power supply line and uses electromotive force generated by electromagnetic induction with the power supply line as power supplied to a load;
The high-frequency power source includes a capacitive reactance that forms a resonance circuit together with an inductance of the feeder line, and a control unit that controls the operation of the capacitive reactance,
The capacitive reactance includes a bridge circuit configured by four semiconductor elements having no reverse blocking capability, and a capacitor that is connected between the midpoints of the bridge circuit and accumulates snubber energy at the time of current interruption,
The control unit performs control so that the on / off operations of the pair of diagonally located semiconductor elements among the four semiconductor elements are simultaneously performed, and when one pair is on, the other A non-contact power feeding system that controls the pair to be turned off.   The controller has an automatic resonance adjustment function that automatically adjusts the resonance of the resonance circuit by adjusting the on / off switching timing of the four semiconductor elements to change the apparent capacitance of the capacitor. The contactless power feeding system according to claim 1, wherein   The contactless power feeding system according to claim 2, wherein the control unit performs resonance adjustment of the resonance circuit as needed by the automatic resonance adjustment function while the system is operating.   The said control part increases the impedance of the said resonance circuit by shifting the said resonance circuit from resonance, when the load of the said power receiving part is less than the predetermined fluctuation | variation range. Contactless power supply system.   5. The contactless power supply according to claim 1, wherein the control unit determines whether or not the resonance circuit is in a resonance state based on an output voltage value of the high-frequency power source with no load. system.   The non-contact power feeding system according to claim 1, wherein the control unit determines whether or not the resonance circuit is in a resonance state based on a ripple current of the high-frequency power source without a load. .

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