JPH10174205A - Power-supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a power-supply apparatus by which a current flowing to a transmission line is increased while the current capacity of an inverter is reduced by using a voltage inverter and a parallel resonance circuit, which reduces a voltage drop due to a reactor for current control and further reduces harmonics. SOLUTION: A voltage inverter 3 is connected to a DC constant-voltage power supply 2, and a capacitor 19 for parallel resonance is installed on its output side so as to be in parallel with a power-supply line 4. Then, a reactor 20, for control, which is required to combine the voltage inverter 3 with a parallel resonance circuit is installed, and a capacitor 21 for parallel resonance is connected to the reactor. Thereby, an impedance is reduced, the Q of the parallel resonance circuit is increased, and harmonics can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device applied to a power supply facility for an article transport cart.

[0002]

2. Description of the Related Art Conventionally, various power supply devices for supplying electric power to a self-propelled moving body or the like from the outside have been known. For example, a conveyance system in which a self-propelled conveyance vehicle moves along a rail track. In the above, a trolley wire is arranged on a rail track, and a current collector that is in sliding contact with the trolley wire is mounted on a transport trolley, electric power is transmitted from the trolley wire to the current collector, and a motor or the like provided on the transport trolley is driven Is generally known. However, according to such a so-called contact-type power supply device, the trolley wire and the current collector are in sliding contact with each other, so that dust due to abrasion is generated, and sparks are easily generated in the sliding contact portion, which may cause a clean room or ignition. Not suitable for location use.

Therefore, as shown in, for example, Japanese Patent Application Laid-Open No. 5-207606, a power supply facility has been proposed in which power is supplied in a non-contact manner using electromagnetic induction so as to prevent generation of dust and the like. I have. That is, in the non-contact power supply equipment disclosed in this publication, a transmission line is arranged along a rail track, and the transmission line is connected to a power supply device having an inverter so that a high-frequency current flows through the transmission line. At the same time, a pickup unit in which a pickup coil is wound around a core member made of a magnetic material is mounted on the carrier, so that an induced electromotive force corresponding to a high-frequency current flowing through the transmission line is generated in the pickup coil.

[0004]

To reduce the current capacity of the inverter of the power supply device while allowing a relatively large current to flow through the transmission line in this kind of non-contact power supply equipment, the above publication is also disclosed in the above publication. As described above, it is desirable that a capacitor is provided in parallel with the transmission line to form a parallel resonance circuit, and that a resonance phenomenon causes a current larger than the inverter current to flow through the transmission line. In this case, the parallel resonance circuit can be directly driven by using a current source inverter as in the power supply device disclosed in the above publication, but this device requires two reactors for current control and commutation, Since the reactor is heavy and bulky, the device becomes heavy and large.

On the other hand, if a voltage-type inverter is used as the inverter, the parallel resonance circuit cannot be directly driven by this inverter, and it is necessary to separately provide a current control reactor. In this case, since the realtor is installed on the AC side, the voltage drop increases. If the inductance is reduced to reduce the voltage drop, there is a problem that the harmonics increase.

In view of the above circumstances, the present invention uses a voltage type inverter and a parallel resonance circuit to reduce the current capacity of the inverter while increasing the current flowing through the transmission line, and to reduce the voltage drop due to the current controlling reactor. It is an object of the present invention to provide a power supply device capable of reducing the harmonics and reducing the harmonics.

[0007]

In order to achieve the above object, the present invention comprises an inverter on a power supply side of a transmission line, a resonance circuit provided in the inverter, and a high-frequency current flowing through the transmission line. In the power supply device, a voltage type inverter is connected to the DC constant voltage power supply, and on the output side of the inverter, a capacitor for parallel resonance connected in parallel with the transmission line is provided, and a control reactor is connected in series with the transmission line. And a capacitor for series resonance.

According to this power supply device, high-frequency AC is supplied by the voltage-type inverter, the current flowing through the transmission line is increased by the resonance circuit, and the waveform of the power supply device approximates a sine wave. In particular, a capacitor for parallel resonance is provided so as to be advantageous in reducing the current capacity of the inverter, and a control reactor and a capacitor for series resonance are provided in series with the power transmission line, so that the parallel resonance is provided. By connecting a series resonance capacitor to the control reactor while effectively driving the circuit, the impedance of this circuit is reduced and the voltage drop is suppressed, and the resonance characteristics of this series resonance circuit are reduced. As Q indicating the sharpness is increased, harmonics are reduced.

In this apparatus, the transmission line is disposed on a transfer path in an article transfer system, and an electromotive force caused by electromagnetic induction is applied to a transfer carriage movable along the transfer path in accordance with a high-frequency current flowing through the transmission line. When a power-supplying body causing the above-mentioned is provided, non-contact power feeding by electromagnetic induction from a power transmission line is effectively performed on the transport vehicle.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the power supply device of the present invention. In this figure, 1 is a three-phase AC power supply, 2 is a DC power supply circuit for converting the AC of the AC power supply 1 to DC of a constant voltage, 3 is an inverter connected to the DC power supply circuit 2, and these are power supply lines. (Transmission line) 4 is provided on the power supply side. The DC power supply circuit 2 includes:
Six diodes 5 for full-wave rectification and a smoothing capacitor 6
To output a constant DC voltage.

The inverter 3 converts DC power into AC having a predetermined frequency, and is composed of a voltage-type inverter. In the illustrated example, four transistors 11 to 14 are provided.
And a single-phase bridge circuit having Each of the transistors 11 to 14 is driven by a rectangular signal provided from the control device 30.
, An AC power of a predetermined frequency can be obtained. Note that diodes 15 to 18 are connected in antiparallel to the transistors 11 to 14, respectively.

A power supply line 4 is connected to the output side of the inverter 3 and a capacitor 19 for parallel resonance connected in parallel with the power supply line 4 is provided. Further, a current control reactor 20 and a series resonance capacitor 21 are provided in series with the power supply line 4.

The parallel resonance capacitor 19 and the feed line 4 constitute a parallel resonance circuit, and the series resonance capacitor 21 and the reactor 20 constitute a series resonance circuit. Is inverter 3
Resonate at the fundamental frequency of That is,
Assuming that the capacitance of the capacitor 19 is C1 and the inductance of the power supply line 4 is L1, the resonance frequency f1 of the parallel resonance circuit is as follows.

F1 = {1 / (2π)}｝ {1 / {(C1 · L1)} The basic frequency, the inductance L1 of the feed line 4 and the inductance L1 of the power supply line 4 are adjusted so that the resonance frequency f1 matches the basic frequency of the inverter 3. The capacity C1 of the capacitor 19 is set. On the other hand, when the capacitance of the capacitor 21 is C2 and the inductance of the reactor 20 is L2, the resonance frequency f2 of the series resonance circuit is as follows.

F2 = {1 / (2π)}｝ {1 / {(C2 · L2)} Further, the value of Q indicating the sharpness of the resonance characteristic is as follows in the case of the series resonance circuit.

Q = (1 / R) · √ (L2 / C2) Therefore, the capacitor is set so that the value of Q is sufficiently increased while satisfying the condition that the resonance frequency f2 is made to coincide with the fundamental frequency of the inverter 3. 21, a capacitance C2 and an inductance L2 of the reactor 20 are set.

FIG. 2 shows the internal structure of the control device 30. The control device 30 includes a control amplifier 31, a PWM
It includes a circuit 32, a gate drive circuit 33, and an optimum frequency detecting means. On the input side of the control amplifier 31,
A line current command is given from an external command means (not shown), and a line current detection value i _L is given from the power supply line 4, and the output of the control amplifier 31 is controlled according to a deviation between these values. The optimum frequency detecting means 34 has a line current detection value i _L given from the power supply line 4.
And an inverter current detection value i _I given from the output side of the inverter 3, and a frequency command obtained by a method as shown in FIG. 3 described later based on these signals is output from the optimum frequency detection means 34. .

The PWM circuit 32 outputs a PWM signal according to the output of the control amplifier 31 and a frequency command from the optimum frequency detecting means 34, and the gate drive circuit 33
According to a signal from the M circuit 32, each of the transistors 11
The drive signals a to d are output to the gates の 14, respectively. In this case, the drive signals a to d have frequencies in accordance with the frequency command from the optimum frequency detection means, and the signals a and d for the transistors 11 and 14 and the signals b and c for the transistors 12 and 13 are mutually different. It is shifted by half a cycle. Moreover, (the ratio of on-time t to the period) the duty of each signal a~d is adjusted based on the difference between the value i _L and the command value of the line current. That is, each signal a~ when the detected value i _L is larger than the command value
d is gradually reduced, and the detection value i
_{When L} is smaller than the command value, the duty of each of the signals a to d is gradually increased. The maximum duty of each of the signals a to d is 50%.

The optimum frequency detecting means 34 in the control device 30 uses a so-called hill-climbing method so as to minimize the inverter current or the output power while keeping the current and load of the power supply line 4 constant. Is adjusted, and more specifically, the frequency is adjusted by a process as shown in the flowchart of FIG.

The process of this flowchart is performed at the time of initialization of the power supply device. When the process is started, first, initialization in the computer is performed (step S1). Next, it is checked whether or not the flag is "1" (step S2). If the flag is not "1", the following processing from step S3 is performed.

[0021] That is, first the frequency is high from a preset fundamental frequency (e.g. 10 kHz) by a predetermined frequency (e.g. 100 Hz) (step S3), and determines whether the inverter current detection value i _I was reduced in that state It is (step S4), and if the inverter current detection value i _I has decreased is flag is "1" with (step S5), and returns to step S3. Then, the process of increasing the frequency by a predetermined frequency, the inverter current detection value i _I is repeated for as long as tends to decrease accordingly.

If it is determined in step S4 that the inverter current does not decrease, the frequency is set to a predetermined frequency (for example, 1).
00Hz) only it is lowered (step S6), and whether the inverter current detection value i _I is reduced is determined in this state
(Step S7), and if the inverter current detection value i _I has decreased flag is "1" with (step S8), and returns to step S6. Then, processing to lower the frequency by a predetermined frequency, the inverter current detection value i _I is repeated for as long as tends to decrease accordingly. If it is determined in step S7 that the inverter current does not decrease, the process returns to step S2, and if the flag is "1", this process ends.

In this manner, the frequency at which the inverter current is minimized is obtained, and this frequency is stored in the nonvolatile memory, and thereafter, the operation is performed at the frequency stored in this memory. The frequency determination process as shown in FIG. 3 may be performed only once in the initial setting stage of the power supply device. However, when the optimum frequency may fluctuate due to aging or the like, the power supply device It may be performed every time at the time of startup, or may be performed periodically.

FIG. 4 and FIG. 5 schematically show the structure of the power transmission line arrangement portion and the power-supplied side when the above-mentioned power supply device is applied to an article transport system. In these figures, 4
Reference numeral 0 denotes a monorail which constitutes a transport path, which is disposed in an elevated state in a factory or the like, is supported by a ceiling or the like via a bracket 41, and the power supply line 4 is connected to one side of the monorail 40. The constituent transmission lines are provided.
The transmission line is attached to one side surface of the monorail 40 via a hanger 43 in a state where the transmission line is connected to the power supply 42 at one end of the monorail 40 and is folded at the other end of the monorail 40 to form a loop. . The power supply device 42 includes an AC power supply 1, a DC power supply circuit 2,
An inverter 3 and the like are provided.

On the monorail 40, a carrier 45 is movably supported. The transport vehicle 45 includes traveling wheels 46 that roll on the monorail 40 and the monorail 4.
The power feeder includes guide rollers 47 and 48 in contact with upper and lower sides, lower sides and a lower surface of the motor 0, a motor 49 for driving the running wheels 46, and the like. The pickup unit 50 is provided. The pickup unit 50 includes a core member 51 made of a magnetic material and having a substantially E-shaped cross section.
And a pickup coil 52 wound around a central projecting portion 51a of the core member 51.
It is arranged so as to correspond to the power supply line 4 arranged at 0. When an alternating current flows through the power supply line 4, a magnetic flux is formed using the core member 51 as a magnetic path, and an electromotive force due to electromagnetic induction is generated by the pickup coil 5.
2, and the electromotive force is supplied to the motor 49 via a controller (not shown) or the like.

The operation of the power supply apparatus according to this embodiment as described above will be described below.

By performing non-contact power supply by electromagnetic induction from the power supply line 4 to the pickup unit 50 of the transport carriage 45, dust and sparks are not generated due to abrasion unlike contact power supply. Suitable for use in clean rooms. Then, for this non-contact power supply, a high-frequency current flows from the power supply device 42 having the inverter 3 to the power supply line 4.

In this case, each of the transistors 15 to 18 of the inverter 3 is driven by a signal from the control device 30 to obtain a high-frequency alternating current. Further, the current capacity of the inverter 3 is reduced by the resonance circuit including the parallel resonance capacitor 19 and the like.
Is increased. In addition, although only the inverter 3 including the transistors 15 to 18 produces a square wave AC, the output is approximated to a sine wave by the resonance circuit.

In the case where a parallel resonance circuit is provided for the voltage type inverter 3, a current control reactor 20 is required. This alone causes problems of voltage drop and harmonics as described above. Since the series resonance capacitor 21 is connected to 20, the impedance of this circuit is reduced and the voltage drop is suppressed.

Further, as described above, the capacitance C2 of the capacitor 21 is set so as to sufficiently increase the value of Q of the series resonance circuit.
In addition, it is possible to set the inductance L2 of the reactor 20. When the value of Q is increased in this way, the sharpness of the resonance characteristics increases, and the harmonics become relatively small. Therefore, adverse effects of noise due to harmonics on other devices and the like are reduced.

When the value of Q is increased, the resonance band is narrowed, and the series capacitor 21 and the reactor 20
Since there is an error between the nominal value and the actual value of the inverter 3, the resonance frequency obtained according to the above-mentioned nominal value and the fundamental frequency of the inverter 3 are simply made to coincide with each other. If the frequency is adjusted by the method shown in FIG. 3 in the control device 30 as in the present embodiment, the frequency of the inverter 3 becomes appropriate so as to correspond to the resonance band. It is adjusted to.

In the examples shown in FIGS. 4 and 5, the apparatus of the present invention is applied to a monorail type transport system.
In addition, the apparatus of the present invention can be used to supply power to various moving bodies and the like that move along a fixed path with electric driving means.

[0033]

As described above, the power supply apparatus of the present invention uses a voltage-source inverter, provides a capacitor for parallel resonance connected in parallel with the transmission line on the output side, and controls the power supply in series with the transmission line. Since the power reactor and the capacitor for series resonance are provided, it is possible to effectively supply power while reducing the current capacity of the inverter and making the device compact.
In particular, by connecting a capacitor for series resonance to the control reactor, it is possible to reduce the impedance of this circuit, suppress a voltage drop, and reduce harmonics.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a power supply device of the present invention.

FIG. 2 is a block diagram of a control unit of the power supply device.

FIG. 3 is a flowchart illustrating an example of frequency control.

FIG. 4 is a schematic front view of an article transport system to which the power supply device is applied.

FIG. 5 is a schematic sectional view of a main part of the transport system.

[Explanation of symbols]

 2 DC power supply circuit 3 Inverter 4 Power supply line (transmission line) 19 Capacitor for parallel resonance 20 Reactor for control 21 Capacitor for series resonance

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02M 7/48 B65G 43/00 L // B65G 43/00 H01F 23/00 B

Claims (2)

[Claims] 1. A power supply device comprising: an inverter on a power supply side of a transmission line; a resonance circuit provided in the inverter; and a high-frequency current flowing through the transmission line. A power supply device comprising, on the output side of this inverter, a capacitor for parallel resonance connected in parallel with a power transmission line, and a control reactor and a capacitor for series resonance provided in series with the power transmission line. . 2. An electromotive force generated by electromagnetic induction according to a high-frequency current flowing through the transmission line, wherein the transmission line is disposed on a transportation path in an article transportation system, and the carriage is movable along the transportation path. The power supply device according to claim 1, further comprising a power-supplied body.