JP2003209903A - Non-contact power feeder and non-contact power feeding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact power feeder for preventing damage to an apparatus caused by an overvoltage, and provide a non-contact power feeding system for controlling a feeding power current by using a simple means. <P>SOLUTION: An output voltage limiting unit 6 is provided in parallel with a resonance circuit unit 5. When an output voltage at a reference voltage or larger is generated, the output of the resonance circuit unit 5 is shunted and the output voltage is reduced. A current in an AC power supply 4 corresponding to the power consumption of a motor 24 is detected and is differentiated by a load detecting unit 81. When the result is a threshold or larger, it is determined that the power consumption increases, so that the constant current fed from the AC power supply 4 to the power feeding line 40 is made increased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless power supply device and a contactless power supply system for supplying an induced electromotive force generated in a pickup coil near a power supply line through which an alternating current flows to a load.

[0002]

2. Description of the Related Art A contactless power supply system is a contactless power supply system for supplying electric power for driving to a motor such as a carrier or an elevator used in a moving body system and a load such as a device connected to the motor. Supply. Japanese Patent Laid-Open No. 8-308151
In the gazette, an alternating current having a constant amplitude or a constant effective current using a constant voltage alternating current power source and an impedance converter (hereinafter,
A contactless power supply system for supplying a constant current) to a power supply line is disclosed, and Japanese Patent Application Laid-Open No. 8-308150 discloses a constant current by obtaining an induced electromotive force from the power supply line to which the constant current is supplied. A constant voltage is applied to the load by using a resonant circuit section that outputs and a constant current output by the resonant circuit section and an impedance conversion section that converts the constant current into an AC voltage with a constant amplitude or a constant effective voltage (hereinafter referred to as a constant voltage). A contactless power supply system for supplying electric power is disclosed.

FIG. 9 is an electric circuit diagram showing a configuration of a conventional contactless power feeding system. Reference numeral 4 in the figure denotes an AC power supply that outputs a constant current, and supplies a predetermined constant current to a power supply line 40 connected to the AC power supply 4. The non-contact power supply device 70 is mounted on a mobile body, receives power from the power supply line 40, and supplies electric power to a motor for running the mobile body and a load such as a device connected to the motor. The non-contact power feeding device 70 includes a pickup coil 51 wound around a pickup core (not shown) that is close to the power feeding line 40 through which an alternating current flows.
A resonance capacitor 52 connected in parallel to the pickup coil 51, an inductor 31a and a capacitor 3
An impedance conversion unit 31 in which 1b and 31c are arranged in a π type, a rectification unit 32 using a diode bridge for rectifying an alternating current into a direct current, and a smoothing unit 33 using a smoothing capacitor for smoothing a voltage are provided. I have it.

In the non-contact power feeding system as described above, when a constant current is applied to the power feeding line 40, the magnetic flux generated around the power feeding line 40 causes the pickup coil 51 to induce the power, and the pickup coil 51 receives the power and picks up the power. The coil 51 and the resonance capacitor 52 output a constant current, the impedance conversion unit 31 converts the constant current into a constant voltage, and the output power is supplied to the motor and the device via the rectification unit 32 and the smoothing unit 33. . FIG. 10 is a graph showing the relationship between the output power and the output voltage of the contactless power supply device 70 of the contactless power supply system. The horizontal axis represents the output power of the non-contact power supply device 70 (power consumption consumed by the load), and the vertical axis represents the output voltage of the non-contact power supply device 70. When the power consumption increases, the magnetic flux density linked to the pickup coil 51 increases and the resonance shifts, or the rectifying unit 32 and the smoothing unit 3
As shown by the characteristic curve in the figure, the output voltage at maximum load is different from the output voltage at no load due to the drooping characteristic of No. 3 and the output voltage decreases when the output power increases. It is known. That is, when the power consumption changes, the output voltage also changes.

The value of the constant current supplied to the power supply line 40 (hereinafter referred to as the power supply line current) is generally the power required by the load when the moving body is traveling at the speed at which it is normally operated ( The AC power source 4 is set in advance according to the rated load). At this time, the relationship between the output power and the output voltage is shown in FIG.
The characteristic curve shown by the solid line in FIG. The device (inverter, servo driver, or the like) supplied with power from the non-contact power supply device 70 has the upper limit voltage and the lower limit voltage (input voltage allowable range) of the input voltage to the device, and the device is outside the input voltage allowable range. The protection circuit of (3) operates and the device stops. When the device is used, for example, when the moving body accelerates and power consumption increases, and the output voltage becomes lower than the lower limit voltage, the protection circuit operates and the device stops, so that the motor of the moving body is It may stop. In order to prevent the operation of the protection circuit, when the power consumption increases, the AC power supply 4 is controlled to increase the power supply line current. The value of the power supply line current at this time is set in advance in the AC power supply 4 so that the output voltage corresponding to the output power at the maximum load falls within the allowable range of the input voltage. When the feeder current increases, the electromotive force of the pickup coil 51 increases,
Since the output voltage increases, the relationship between the output power and the output voltage becomes like the characteristic curve shown by the alternate long and short dash line in FIG.

[0006]

However, when the power supply line current is increased, the power consumption decreases, and the output voltage exceeds the upper limit of the input voltage of the device fed from the contactless power feeding device 70. In that case, there is a problem that the device may be damaged. In the case of using a contactless power supply device corresponding to a large rated load in order to prevent damage to the device and also to prevent the protection circuit of the device from operating, the contactless power supply device may be a pickup core or a core having a large cross-sectional area. Since the large-capacity smoothing capacitor and the like are provided, there is a problem that the contactless power feeding device becomes large.

When supplying a large power supply line current (for example, a power supply line current set in accordance with the maximum load),
Since the power supply line loss (for example, resistance loss) increases and the cost also increases, it is necessary to adjust the power supply line current according to changes in power consumption. Therefore, JP-A-8-251843
Japanese Patent Laid-Open Publication No. 2001-242242 discloses a contactless power feeding system in which a change in power consumption is estimated and calculated from various amounts detected when an AC power source operates, and the power supply line current is controlled based on the calculation result. In Japanese Patent Laid-Open No. 19120, there is disclosed a contactless power feeding facility that has means for outputting movement status data (starting, deceleration, stop, and constant speed) of a moving body, and controls a power supply line current based on the movement status data. ing.
However, the contactless power supply system disclosed in Japanese Unexamined Patent Publication No. 8-251843 requires a complicated power consumption estimation circuit for estimating the total power consumed, and
There is a problem that the power supply line current cannot follow when the power consumption changes rapidly. In addition, JP 2001-19
In the contactless power feeding equipment disclosed in Japanese Patent Publication No. 120, it is necessary to provide the moving body with the means and a means (for example, an optical communication device) for transmitting movement status data to an AC power source, and the structure of the moving body is There was a problem that it became complicated.

Further, in US Pat. No. 4,914,539,
Disclosed is a contactless power supply system that adjusts an output voltage by shunting an output current of a resonant tank circuit that is inductively coupled to a supplied power supply line with an FET (field effect transistor) in order to prevent an overvoltage of the output voltage. However, since the FET is used to convert a constant current into a constant voltage, the FET shunts the current for a long time, which limits the power receiving capability of the pickup coil to an unnecessarily high level. There was a problem that efficiency deteriorated.

The present invention has been made to solve such a problem, and a shunt that shunts the electric power output by the pickup coil and the resonance capacitor when the output voltage supplied to the load exceeds the reference voltage. By providing the part in parallel with the resonance capacitor,
When the voltage is lower than the reference voltage, the shunt part can be kept in the off state, and therefore, it is possible to prevent the device being fed from the device from being damaged by the excessive output voltage without deteriorating the power receiving efficiency. It is an object of the present invention to provide a contactless power supply device which can be prevented and can be downsized.

Another object of the present invention is to cause the light emitting element of the photocoupler to emit light when the comparator detects that the output voltage supplied to the load has become higher than the reference voltage, and the light receiving element of the photocoupler An object of the present invention is to provide a contactless power supply device that can turn on or off the shunt unit based on the comparison result output from the comparison unit by turning on the shunt unit when receiving light. Another object of the present invention is to
An object of the present invention is to provide a contactless power supply device including a shunt unit that can shunt the power output by a pickup coil and a resonance capacitor by using a rectification unit and a transistor that is turned on or off by a switching unit.

Another object of the present invention is to provide a contactless power supply device which can be downsized by providing a current limiting means for reducing the current flowing through the shunt portion. Another object of the present invention is to provide a non-contact power feeding device that can further reduce the size of the shunt portion by using a coil as the current limiting means.

Another object of the present invention is to detect a change in the power consumed by the load based on the change in the current or voltage related to the AC power source and control the power supply line current in accordance with the change in the power to obtain the load. It is not necessary to provide a load with a means for detecting the power consumed by the power supply or a change in the power, the power supply line current can be adjusted according to the power, and power is supplied from the device by an excessive output voltage. To provide a contactless power supply system capable of preventing the operation of the device from being stopped due to the activation of a protection circuit of the device, suppressing the loss of a power supply line and an increase in cost, and downsizing the contactless power supply device. It is in. Another object of the present invention is to detect a current or a voltage related to an AC power source, detect an increase or decrease in the power consumed by a load based on a differential value of the current or the voltage, and determine a power supply line current according to the increase or decrease in the power. An object of the present invention is to provide a non-contact power feeding system that can control the power feeding line current according to the power consumed by the load with a simple configuration without providing a means for performing complicated calculation by controlling.

Another object of the present invention is to detect a change in power consumed by a load on the basis of a change in current or voltage related to an AC power source, and based on the change in power and the elapsed time measured from a predetermined time point. It is to provide a contactless power supply system capable of adjusting the power supply line current according to the power consumption with a simple configuration by controlling the power supply line current by means of a simple structure without providing a means for performing a complicated calculation. . Still another object of the present invention is to provide a means for controlling a power supply line current according to a change in power consumed by a load, and a means for limiting an output voltage supplied to the load to a reference value voltage or less, When the power consumption sharply decreases and the output voltage sharply increases, even if it is not possible to sharply reduce the feeder line current to reduce the output voltage, the power receiving efficiency is not deteriorated and excess power is not reduced. An object of the present invention is to provide a contactless power supply system capable of preventing damage to equipment due to output voltage.

[0014]

According to a first aspect of the present invention, there is provided a contactless power supply device, wherein the pickup coil and a resonance capacitor convert a voltage induced in a pickup coil inductively coupled to a power supply line through which an alternating current flows into a constant current, Also, in a contactless power supply device that includes an impedance conversion unit that converts the constant current into a constant voltage, a reference voltage generation unit that generates a reference voltage, corresponding to the reference voltage and the output power in a contactless power supply device that supplies output power to a load. A comparison unit that compares the voltage with
And a shunt unit provided in parallel with the resonant capacitor, the switching unit having an ON state when the comparison unit detects that the voltage has become equal to or higher than the reference voltage. To do.

According to the first aspect of the present invention, in order to compare the reference voltage generated by the reference voltage generator with the voltage (eg output voltage) corresponding to the output power supplied to the load, The reference voltage generating unit and the output unit for connecting a load, for example, are connected in advance. The shunt section is normally kept in the off state, and when the output voltage becomes equal to or higher than the reference voltage, the shunt section is turned on by the switching means, and the shunt section in the on state outputs the power output by the pickup coil and the resonance capacitor. Shunt. At this time,
Since the electric power supplied from the pickup coil and the resonance capacitor to the impedance conversion unit becomes substantially zero, the output power does not exceed the reference voltage and rises, and conversely, the output voltage can be reduced. That is, when the maximum input voltage within the allowable input voltage range of the device fed from the device is used as the reference voltage, damage to the device due to excessive output voltage can be prevented.

Further, since the output voltage can be prevented from excessively rising by shunting the electric power output from the pickup coil and the resonance capacitor, the output voltage from no load to the maximum load can be prevented in order to prevent the damage of the equipment. It is not necessary to use a large contactless power supply device including a component having an input voltage allowable range up to the output voltage, such as a pickup core having a large cross section or a large-capacity smoothing capacitor, and the device can be downsized. . Further, the pickup coil, the resonance capacitor, and the impedance conversion unit receive the constant current output from the pickup coil and the resonance capacitor, which is received by the pickup coil that is inductively coupled to the energized power supply line, and the impedance conversion unit outputs the constant current. Since it can be supplied to the load after being converted to a constant voltage with, it is not necessary to convert the constant current output by the resonance capacitor to a constant voltage with a shunt part using an FET, for example, and the output voltage is less than the reference voltage. In this case, the shunt part can be kept in the off state, and the power receiving efficiency is not deteriorated.

Further, even when the power consumption of the load does not change, for example, when the distance between the power supply line and the pickup coil decreases and the output voltage rises, the device is damaged by the excessive output voltage. Since this can be prevented, the shunt portion can function as a protection circuit for the device.

FIG. 11 is a graph showing the relationship between the output power and the output voltage of the contactless power supply device of the present invention. The horizontal axis represents the output power (power consumption of the load) output from the non-contact power supply device, and the vertical axis represents the output voltage output from the non-contact power supply device. As indicated by the solid curve in the figure, the output voltage decreases as the output power increases.

When the power supply line current is supplied according to the rated load, the relationship between the output power and the output voltage is as shown by the characteristic curve shown by the solid line in the figure. When the power consumption increases and exceeds the rated load, it is prevented that the output voltage falls below the minimum input voltage within the allowable input voltage range of the device and the protection circuit of the device operates to stop the operation of the device. In order to do so, it is common practice to control the AC power supply to supply a large feeder current. At this time, in the present invention,
The relationship between the output power and the output voltage is as shown by the characteristic curve shown by the alternate long and short dash line in the figure. When the power supply current is supplied, the power consumption decreases and the output voltage increases, and when the output voltage exceeds the maximum input voltage within the allowable input voltage range, the shunt section is turned on to prevent damage to the equipment. State,
The output voltage is limited to the maximum input voltage or less. If the output voltage is less than the maximum input voltage, or if the output voltage decreases below the maximum input voltage after the operation of the shunt unit, the shunt unit is turned off, and the output voltage increases the power consumption ( It decreases (increases) according to the decrease.

A contactless power supply device according to a second aspect of the present invention includes a photocoupler having a light emitting element and a light receiving element for receiving light emitted by the light emitting element, and the switching means includes the light receiving element. The shunt unit is configured to be turned on when the light receiving element receives light, and the comparison unit is configured to cause the light emitting element to emit light when detecting that the voltage becomes equal to or higher than the reference voltage. It is characterized by being.

In the second invention, the photocoupler has a light emitting diode and a phototransistor, and the phototransistor is used as a switching means of the shunt portion. The comparing unit is connected to the reference voltage generating unit and, for example, an output unit to which a load is connected, and compares the reference voltage generated by the reference voltage generating unit with the output voltage output by the non-contact power supply device, and outputs the output. When the voltage becomes equal to or higher than the reference voltage, a predetermined current is output to the light emitting diode to cause the light emitting diode to emit light. When the phototransistor receives the light emitted from the light emitting diode, a current is passed through the shunt portion to turn on the shunt portion. The shunt unit shunts the electric power output from the pickup coil and the resonance capacitor, makes the electric power output from the pickup coil and the resonance capacitor substantially zero, and reduces the output voltage.

When the output voltage is less than the reference voltage, the comparison section does not output the current to the photocoupler, and the photocoupler does not flow the current to the shunt section. At this time, the shunt section is turned off, and the power output by the pickup coil and the resonance capacitor is not shunted.
Electric power is supplied from the pickup coil and the resonance capacitor to the impedance converter. As a result, it is possible to efficiently limit the power receiving capacity of the pickup coil and prevent damage to the device being fed from the device due to an excessive increase in the output voltage without deteriorating the power receiving efficiency.

In a contactless power supply device according to a third aspect of the present invention, the shunt section includes a transistor that is turned on when the switching means is turned on, and a rectification section,
The rectification unit and the transistor are provided in parallel with the resonance capacitor.

According to the third aspect of the present invention, the comparison section is connected to the reference voltage generation section and, for example, the output section connected to the load, and the reference voltage generated by the reference voltage generation section is supplied to the load. Output voltage. Since the current flowing through the resonant capacitor is an alternating current, the rectifying section of the shunt section is provided in parallel with the resonant capacitor, and the transistor is provided in parallel with the rectifying section. The transistor is normally turned off, and when the output voltage becomes equal to or higher than the reference voltage, it is turned on by the switching means. The output of the rectification unit is short-circuited using the transistor in the ON state, and the short-circuited output shunts the power output by the pickup coil and the resonance capacitor. At this time, the electric power supplied from the pickup coil and the resonance capacitor to the impedance conversion unit becomes substantially zero, so that the output power does not exceed the reference voltage and rises, and conversely, the output voltage can be reduced. That is, when the maximum input voltage within the allowable input voltage range of the device fed from the device is used as the reference voltage, damage to the device due to excessive output voltage can be prevented.

When the phototransistor of the photocoupler is used as the switching means of the transistor, the comparison unit compares the reference voltage generated by the reference voltage generation unit with the output voltage output by the non-contact power supply device. hand,
When the output voltage becomes equal to or higher than the reference voltage, a predetermined current is output to the light emitting diode of the photocoupler to cause the light emitting diode to emit light, and the phototransistor receiving the light emitted by the light emitting diode supplies a current to the transistor. The shunt part can be turned on by pouring.

A contactless power supply device according to a fourth aspect of the present invention is characterized in that the shunt portion has current limiting means for reducing a current flowing through the shunt portion. In the fourth invention, for example, a resistor is used as the current limiting means, and when the shunt portion is turned on, the current flowing through the shunt portion is reduced by the resistor to limit the current. When the shunt portion is configured by using the component having the current capacity corresponding to the current thus limited, the component has the electric capacity corresponding to the current when the current flowing through the shunt portion is not limited. It has a smaller electric capacity and a smaller size.
That is, by providing the shunt portion with the current limiting means, the shunt portion can be downsized.

In the contactless power supply device according to the fifth aspect of the present invention, the current limiting means is a coil.
In the fifth aspect of the invention, for example, the shunt unit is configured using a rectifying unit that uses a diode bridge that rectifies an alternating current into a direct current and a transistor, and the rectifying unit is provided in parallel with the resonance capacitor. , A transistor is provided in parallel with the rectification unit, and in series with the transistor,
A coil that is a current limiting means is provided. When the shunt portion is turned on, the current flowing through the transistor has a full-wave rectified waveform rather than a complete DC waveform.
At this time, the current is reduced by making the coil blunt the current waveform of the current.

The shunt section as described above obtains a similar current limiting effect as compared with a shunt section in which a resistor is provided in place of the coil for the shunt section (a current capacity corresponding to the limited current is obtained). When the shunt portion is miniaturized by using the transistor included therein, the shunt portion can be further miniaturized because it can be configured by using a coil having a resistance value smaller than that of the resistor. Further, since the resistance value of the coil is smaller than the resistance value of the resistor, the loss in the coil is smaller than the loss (resistance loss) in the resistor. Therefore, the amount of heat generated by limiting the current can be reduced.

A contactless power supply system according to a sixth aspect of the present invention is a contactless power supply system which includes a contactless power supply device for contactlessly receiving power from a power supply line through which an alternating current flows and supplying power to a load. A detector that detects a current or a voltage related to a power source, a power detection unit that detects whether or not the power consumed by the load has changed, based on a change in the current or the voltage detected by the detector, and the power detection When the unit detects a change in the electric power, the unit includes a control unit that controls the AC power source to supply a current according to the change in the electric power to the power supply line.

According to the sixth aspect of the invention, a detector for detecting a current or a voltage is provided, wherein the detector changes the current or voltage (the output power of the contactless power supply device) in accordance with a change in the power consumption of the load. For example, it is provided at an appropriate position inside the AC power supply or outside the AC power supply in order to detect a current that increases when the power consumption increases. Unlike the heat source, the load of the motor and equipment provided in the moving body generally increases gradually without sharply increasing the power consumption. In addition, usually, the moving body,
The operation is repeated by stopping, accelerating, moving at a constant speed (constant speed), decelerating, and stopping, so the power consumption gradually increases when acceleration starts and decreases when the acceleration ends. However, the power consumption is substantially constant during constant speed and stop. Moreover, during deceleration, power consumption tends to be substantially constant or decreasing.

Therefore, when the current or voltage maintains a substantially constant value and then the current or voltage starts to increase or decrease, the power consumption is increased after the current or voltage starts to increase or decrease. Can start increasing or decreasing. Therefore, the power detection unit can detect the time point when the power consumption starts to increase or the power consumption starts to decrease based on the detection result of the detector. At this time,
Since the control means can adjust the power supply line current according to the change in the power consumption, the protection circuit of the device fed from the non-contact power feeding device is activated by the excessive output voltage to operate the device. It is possible to prevent the power supply from stopping, and to prevent the power supply line loss from increasing and the cost to increase by continuing to supply the increased power supply line current.

When the power supply line current is increased when the power consumption is increased, the coil current flowing in the pickup coil provided in the contactless power supply device can be reduced,
Therefore, the heat generation of the coil can be reduced, and the magnetic flux density linked to the pickup coil can be reduced, so that the pickup core and the pickup coil can be downsized. Further, since the current (voltage) of the resonance capacitor provided in the contactless power supply device can be reduced, the resonance capacitor can be downsized. That is, the device can be downsized by increasing or decreasing the power supply line current according to the power consumption.
Furthermore, since a detector for detecting current or voltage can be provided in the AC power supply, it is not necessary to provide a detector for detecting power consumption in the mobile body.

FIG. 12 shows the output voltage and output power (power consumption of load) of the contactless power supply device of the contactless power supply system of the present invention, the current inside the AC power supply corresponding to the output power, and the power supply line current. It is a graph which shows the relationship of. 12
In each of (a) to (c), the horizontal axis represents time, and the vertical axis in (a) represents the output voltage of the contactless power supply device and the power consumption of the load.
The vertical axis in (b) is the current inside the AC power supply corresponding to the power consumption, and the vertical axis in (c) is the feeder current. A moving body such as a transport vehicle or an elevator repeats stop, acceleration, constant speed, deceleration, and stop over time.

When the moving body is stopped (no load), the power consumption is substantially constant at the minimum value and the output voltage is substantially constant at the maximum value. For this reason, the current inside the AC power supply corresponding to the power consumption is also substantially constant at the minimum value. At this time, the first current is supplied to the power supply line. When the mobile body accelerates (no load to maximum load), the power consumption increases, and the output voltage decreases as the power consumption increases. Therefore, the current inside the AC power supply corresponding to the power consumption also increases.
When the current starts increasing, a second current larger than the first current is supplied to the power supply line.

When the moving body stops accelerating and moves at a constant speed (rated load), it consumes less electric power than during accelerating, and the output voltage corresponding to the electric power becomes greater than during accelerating. Therefore, the current inside the AC power supply corresponding to the power consumption is also smaller than that during acceleration. Further, when the moving body decelerates and stops, it consumes less electric power than the electric power, so that the power consumption gradually decreases and the output voltage gradually increases. Therefore, the current inside the AC power supply corresponding to the power consumption also decreases in a stepwise manner. The power supply line current is at a predetermined timing (for example, from the time when the moving body starts decelerating,
When the average time required for the moving body from decelerating to stopping has elapsed), the second current is returned to the first current. Note that substantially the same result is obtained even when the voltage inside the AC power supply corresponding to the power consumption or the power supply line voltage is used as the vertical axis in FIG. 12B.

In the contactless power supply system according to the seventh aspect of the present invention, the power detection unit differentiates a signal of current or voltage (current or voltage related to an AC power source connected to the power supply line) detected by the detector. It is characterized by detecting whether or not the power has increased or decreased. In the seventh invention, for example, a known differentiating circuit is used as the power detection unit,
The current or voltage signal detected by the detector is input to the power detection unit to differentiate the current or voltage (time differentiation). When the differential value, which is the rate of change of the current or voltage, holds approximately 0 and then increases or decreases, it can be seen that the power consumption has started increasing or decreasing. That is, by detecting the time when the differential value starts to increase or decrease based on the detection result of the power detection unit, it is possible to detect the time when the power consumption starts to increase or the time when the power consumption starts to decrease. Therefore, it is possible to detect an increase or decrease in power consumption and efficiently adjust the feeder current with a simple configuration without performing complicated calculations.

FIG. 13 shows the relationship between the current inside the AC power supply corresponding to the output power (power consumption of the load) of the contactless power supply of the contactless power supply system of the present invention, the differential value of the current, and the power supply line current. It is a graph shown. 13 (a) to (c)
Is the time on the horizontal axis, the vertical axis of (a) is the current inside the AC power supply corresponding to power consumption, the vertical axis of (b) is the differential value of the current, and the vertical axis of (c) is the feeder line. It is an electric current. When the moving body is stopped (no load), the current inside the AC power supply corresponding to the power consumption is a minimum value and substantially constant. For this reason,
The differential value of the current is approximately zero. At this time, the first current is supplied to the power supply line. When the mobile body accelerates (no load to maximum load), the current inside the AC power supply corresponding to the power consumption increases. Therefore, the differential value of the current becomes a positive real value. At this time, the second current larger than the first current is supplied to the power supply line.

When the moving body stops accelerating and moves at a constant speed (rated load), the current inside the AC power source corresponding to the power consumption becomes a substantially constant value which is smaller than that during acceleration.
Therefore, the differential value of the current becomes substantially zero. Further, when the moving body decelerates and stops, the current inside the AC power supply corresponding to the power consumption gradually decreases. Therefore, the differential value of the current is approximately 0. The power supply line current is, for example, after a predetermined time has elapsed after the differential value has reached the real value, or after a predetermined time has elapsed since the differential value has become substantially zero after the differential value has reached the real value, Return from the second current to the first current.

In the non-contact power feeding system according to the eighth aspect of the invention, the current command generating means for generating a plurality of current command signals and the current command signal are received, and a current having a magnitude corresponding to each of the current command signals is generated. And a power supply means for supplying power to the power supply line,
The control means controls the time measuring means and the current command generating means to generate a current command signal so that the power feeding means supplies the first current; and when the first current is supplied, A means for controlling the current command generating means to generate a current command signal so that the power feeding means supplies a second current larger than the first current when an increase in the power is detected; Is detected, or when the decrease in the power is detected after the increase in the power is detected, a means for starting the measurement of the elapsed time using the timekeeping means, and the predetermined elapsed time And a means for controlling the current command generating means to generate a current command signal so that the power feeding means supplies the first current when the elapsed time has elapsed.

In the eighth aspect of the invention, the control means controls the current command generating means to normally generate a predetermined current command signal for supplying the first current to the power supply line. When the current or voltage detected by the detector changes and it is detected that the power consumption of the load increases, the current command generating means is controlled to supply the second current larger than the first current to the power supply line. A predetermined current command signal is generated. In addition, when a predetermined time elapses from the time when the power consumption is increased and the second current is supplied, or when the power consumption is started to decrease during the supply of the second current, the time measuring means is used for a predetermined time. The first current is supplied when is passed. As described above, the first current is normally supplied, the second current is supplied when the power consumption increases, and the first current is supplied again after an appropriate time when the power consumption decreases. The power supply line current can be efficiently adjusted according to the power consumption with a simple configuration without performing complicated calculation.

In the contactless power supply system according to a ninth aspect of the present invention, the contactless power supply device converts the voltage induced in the pickup coil inductively coupled with the power supply line into a constant current, and a resonance capacitor, and A reference voltage generator that includes an impedance converter that converts the constant current into a constant voltage, supplies output power to a load, and also generates a reference voltage, and compares the reference voltage with a voltage corresponding to the output power. And a shunt unit provided in parallel to the resonant capacitor, the switching unit having an ON state when the comparison unit detects that the voltage becomes equal to or higher than the reference voltage. It is characterized by

In the ninth aspect of the invention, when the power consumption sharply decreases and the output voltage sharply increases, even when the power supply line current cannot be sharply decreased to reduce the output voltage. As the non-contact power feeding device, for example, the non-contact power feeding device according to the first invention, the second invention, or the third invention is used, and when the output voltage output to the load is equal to or higher than the reference voltage, the resonance of the resonance capacitor occurs. To prevent the pickup coil from supplying the power received by the pickup coil to the impedance conversion unit to reduce the output voltage, so that the device fed from the contactless power feeding device is damaged by the excessive output voltage. Can be prevented, and the same effect as that of the non-contact power supply line device can be obtained.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. (Embodiment 1) FIG. 1 is a schematic perspective view showing a configuration of a mobile body system using a contactless power supply system according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a rail that constitutes a monorail type moving body system.
Is installed on the ceiling of a factory or warehouse. Rail 1
, Each of which is driven and controlled by the system controller 41, are suspended, and each mobile body 2 obtains driving power through a contactless power supply system including an AC power supply 4. .

FIG. 2 is a schematic side view showing the structures of the moving body 2 and the rail 1 provided in the moving body system, and FIG.
FIG. 4 is a schematic front view showing a configuration of the moving body 2 and the rail 1, and FIG. 4 is a sectional view showing a power supply line 40 and a pickup coil 51 of the contactless power supply system. Rail 1
Has an I-shaped cross-sectional shape, and on one side surface of the rail 1,
The support arms 11, 11, ... Are provided at appropriate intervals in the longitudinal direction, and the rails 1 are suspended substantially horizontally from the ceiling by the support arms. A mounting plate 12a is screwed to the other side surface of the rail 1, and support members 12b, 12 made of a large number of rod-shaped members are provided at the center of the mounting plate 12a.
b, ... Are provided substantially horizontally.

The power supply line 40 is connected to the AC power supply 4, is supplied with a constant current from the AC power supply 4, and is fixed to the tips of the supporting members 12b, 12b, ... It is attached along with. Mobile unit 2
A pair of front and rear body frames 21 and 22 having a U-shape when viewed from the front are provided, and a front wheel 21a and a rear wheel 22a are rotatably provided on upper portions of the body frames 21 and 22, respectively.
a is in rolling contact with the rail 1. In addition, the body frame 21
In the vicinity of the front wheel 21a, a traveling motor 24 connected to the front wheel 21a is fixed. The carrier 23 is the body frame 2
1, 22 provided to the lower part of each body frame 21,
It is hung on the lower side of the rail 1 by means of 2, and it is possible to detachably attach the transported object.

The moving body 2 is configured to obtain driving power from the power feeding line 40 via the non-contact power feeding device 7 mounted on the moving body 2, and the pickup coil included in the non-contact power feeding device 7 is provided. Pickup core 5 wound with 51
3 is fixed to the rail 1 side of the body frame 21. The pickup core 53 is a magnetic body having a U-shaped cross section, and includes a back portion 53c around which the pickup coil 51 is wound, and projections 53a and 53b provided side by side at both ends of the back portion 53c. Have.

When the moving body 2 is mounted on the rail 1, the pickup core 53 faces the power supply line 40 with a predetermined space, and the power supply line 40 is positioned between the protrusions 53a and 53b. To do. The non-contact power supply device 7 including the pickup coil 51 is connected to the motor 24, and when the AC power supply 4 energizes the power supply line 40, the power supply line 40
A magnetic flux that changes with time is formed around the coil, and the induced electromotive force generated in the pickup coil 51 is supplied to the motor 24 by interlinking the magnetic flux with the pickup coil 51. .

FIG. 5 is an electric circuit diagram showing the configuration of the non-contact power feeding device 7 of the non-contact power feeding system. In the figure, reference numeral 40 denotes a power supply line connected to the AC power supply 4, and the pickup coil 51 of the contactless power supply device 7 mounted on the moving body 2 is close to the power supply line 40. The contactless power supply device 7 includes a resonance circuit section 5 having the pickup coil 51 and a resonance capacitor 52 connected in parallel to the pickup coil 51, a power receiving section 3, and an output voltage limiting section 6. The resonance circuit unit 5 is configured so that the inductance of the pickup coil 51 and the capacitance of the resonance capacitor 52 are in resonance with the frequency of the feeder current, and receives the power induced in the pickup coil 51 to function as a constant current source. To do.

The power receiving section 3 includes an impedance conversion section 31 for converting a constant current output from the resonance circuit section 5 into a constant voltage,
A rectifying section 32 using a diode bridge for full-wave rectifying the constant voltage AC current output from the impedance converting section 31, and a smoothing section 33 using a smoothing capacitor for smoothing the voltage output by the rectifying section 32. Equipped with. A motor 24 is connected to an output terminal (not shown) of the power receiving unit 3, and a device (not shown) such as an inverter or a servo driver is connected to the motor 24. The device is supplied with power from the contactless power supply device 7. Impedance converter 31
Is configured such that the inductor 31a and the capacitors 31b and 31c are arranged in a π type, and the inductance of the inductor 31a and the capacitance of the capacitors 31b and 31c are in a resonance state.

The output voltage limiting section 6 is provided with an FET 62 and a rectifying section 61 using a diode bridge for rectifying an alternating current into a direct current in parallel with the resonant capacitor 52. In addition, the output voltage limiting unit 6 includes a reference voltage generating unit 65 that generates a reference voltage and a comparing unit 64, and an input unit of the comparing unit 64 includes an output unit of the power receiving unit 3 (the smoothing unit 33 and the motor 24). Between) and the reference voltage generator 65 are connected to each other. Furthermore, the output voltage limiting unit 6 includes a photocoupler 63 having a phototransistor 63a and a light emitting diode 63b, and the FET 62 is connected to the phototransistor 6a.
3a and the comparison unit 64 is connected to the light emitting diode 63b, whereby the comparison unit 64 and the FET 62 are connected by the photocoupler 63. The value of the reference voltage generated by the reference voltage generator 65 is set in advance to a value equal to or less than the maximum input voltage value within the allowable input voltage range of the device.

When the impedance converter 31 is formed by using the inductor 31a and the capacitors 31b and 31c, the inductor 31a and the capacitor 31 are used.
In addition to arranging b and 31c in a π type, the inductor 3
The inductance of 1a and the capacitances of the capacitors 31b and 31c may be arranged in a T-type so that they are in resonance. In addition, the impedance converter 31 has two inductors 1 and 1 arranged in a π-type or T-type so that the inductance and the capacitance are in a resonance state.
It may be configured by using one capacitor. Further, the rectification unit 32 may be configured by using a diode for half-wave rectification instead of the diode bridge for full-wave rectification.

The non-contact power feeding device 7 as described above is provided with the power feeding line 4
When a constant current is applied to 0, the resonance circuit section 5 outputs a constant current in response to the voltage induced in the pickup coil 51 by the magnetic flux generated around the power supply line 40, and the constant current is converted into the impedance conversion section 31. Converts the voltage into a constant voltage and supplies power to the motor 24 and the device via the rectifying unit 32 and the smoothing unit 33.

The comparison unit 64 compares the reference voltage generated by the reference voltage generation unit 65 with the output voltage output to the motor 24. When the output voltage becomes equal to or higher than the reference voltage, the comparing unit 64 causes the light emitting diode 63b of the photocoupler 63 to operate.
When a predetermined current is output to the light emitting diode 63b, the light emitting diode 63b emits light, and an induced electromotive force is generated in the received phototransistor 63a. At this time, FET
A voltage is applied to 62, a current flows through the FET 62, and FE
Since T62 is turned on, the output of the rectification unit 61 is short-circuited, the short-circuited output shunts both ends of the resonance capacitor 52 connected in parallel with the rectification unit 61, and the output voltage of the resonance circuit unit 5 is reduced. And the output current becomes almost 0, and the power receiving unit 3 is no longer supplied with power. Therefore, the smooth portion 3
3 is discharged and the accumulated electric power is supplied to the motor 24, and the output voltage is reduced.

When the output voltage decreases and becomes less than the reference voltage, the comparison unit 64 stops the output of the current to the light emitting diode 63b, the light emission of the light emitting diode 63b stops, and the phototransistor 63a induces. Since no electric power is generated, no current flows in the FET 62 and the FET 62 is turned off, and the rectification unit 61 and the resonance capacitor 52 are not shunted. Therefore, the contactless power supply device 7 operates in the resonance circuit unit 5
Also, power is supplied to the motor 24 via the power receiving unit 3. At this time, the discharged smoothing unit 33 is charged, and the output voltage rises to a voltage corresponding to the output power.

As described above, the non-contact power feeding device 7 of the present embodiment monitors the output voltage using the output voltage limiting unit 6, and when the output voltage is less than the reference voltage, the resonance circuit unit 5 When the output voltage becomes equal to or higher than the reference voltage when the power is supplied from the resonance circuit unit 5 to the power receiving unit 3, the power supply from the resonance circuit unit 5 is cut off, and then the output voltage becomes less than the reference voltage. Then, the supply of power from the resonance circuit unit 5 to the power receiving unit 3 is restarted. That is, the output voltage can be reduced before the output voltage exceeds the input voltage allowable range of the non-contact power supply device 7. Therefore, the contactless power feeding device 7 can prevent the device from being damaged by an excessive output voltage.
Further, since the output voltage can be limited to the reference voltage or less, the fluctuation range of the output voltage can be reduced.

Even if the non-contact power feeding device 7 does not have an AC power regenerating function, a negative torque is applied to the motor 24 to generate regenerative power, and the voltage of the non-contact power feeding device 7 rises abnormally. Since the output voltage limiting unit 6 cuts off the power supply to the power receiving unit 3 and causes the regenerative power to be consumed by another electric device connected to the contactless power feeding device 7, the voltage can be reduced. It is possible to prevent damage to the device due to overvoltage. In addition, even if the distance between the power supply line 40 and the pickup core 53 or the pickup coil 51 becomes smaller than a predetermined distance due to the shaking of the moving body 2, an accident, or the like, and the output voltage rises,
The output voltage limiting unit 6 can prevent the output voltage from exceeding the reference voltage.

Further, since the non-contact power feeding device 7 outputs the constant voltage by using the impedance converter 31 instead of the FET 62, the FET 62 may operate only when the output voltage is equal to or higher than the reference voltage. When the output voltage is less than the reference voltage, the output voltage limiting unit 6 does not operate, so that the capacity of the pickup coil 51 can be maximized. Further, since the FET 62 is turned on / off by the phototransistor 63a and the light emitting diode 63b,
Switching is faster than mechanical switching, and noise does not occur.

(Embodiment 2) FIG. 6 is an electric circuit diagram showing a configuration of a contactless power supply system according to Embodiment 2 of the present invention. Reference numeral 7 in the figure is a non-contact power feeding device, and the non-contact power feeding device 7 includes a power receiving unit 3 connected to a motor 24, a resonance circuit unit 5 having a pickup coil 51 and a resonance capacitor 52, and the resonance circuit unit 5. The output voltage limiting unit 6 for appropriately shunting the output of to limit the output voltage,
The pickup coil 51 and the power supply line 40 are arranged close to each other.

The AC power source 4 rectifies and smoothes the output of the commercial AC power source 408, and a rectifying / smoothing unit 400 composed of a diode bridge and a smoothing capacitor, and the rectifying / smoothing unit 400.
In order to convert the output of the smoothing unit 400 into an alternating current, an inverter unit 401 composed of power transistors, and an inductor 42a, 42b and a capacitor 42c are connected to a T in order to convert the alternating current output from the inverter unit 401 into a constant current. And an impedance converter 402 arranged in a mold. The impedance conversion unit 402 includes the inductor 4
The inductances of 2a and 42b and the capacitance of the capacitor 42c are configured to be in resonance with the frequency of the feeder current. The power supply line 40 is connected to the output section of the impedance conversion unit 402, and the AC power supply 4 supplies a constant current to the power supply line 40.

Further, the AC power source 4 outputs the required power supply line current, the CPU 407, the current command generator 403 which is controlled by the CPU 407 to generate the current command signal which is the reference value signal, and the power supply line. A current sensor 405 that detects the value of the constant current output to 40, and is connected to the current sensor 405 and the inverter unit 401, receives the current command signal, and based on the detection result of the current sensor 405, A pulse width control unit 404 that feeds back the detection result to control the inverter unit 401 and adjusts the constant voltage output from the inverter unit 401.

As the current command signal, the first current command signal and the second current command signal are used, and when the first current command signal is transmitted to the pulse width control unit 404, the pulse width control unit is the inverter. By controlling the section 401 and adjusting the pulse width at which the power transistor of the inverter section 401 is turned on, the first constant current to be supplied to the power supply line 40 at the normal time is generated, and the second current command signal is pulsed. When transmitted to the width control unit 404, a second constant current larger than the first constant current to be supplied to the power supply line 40 is generated when the motor 24 is at maximum load.

The current sensor 82 is provided inside the impedance converter 402. When the current sensor 82 is provided inside the impedance conversion unit 402, a change in the current detected by the current sensor 82 and a change in the output power supplied to the motor 24 (power consumption of the motor 24) are located at positions corresponding to each other. , A current sensor 82 is provided. In the present embodiment, the current of the capacitor 42c is detected. Current sensor 8
The detection result of No. 2 is given to the load detection unit 81, and the load detection unit 81 uses a known differentiation circuit to differentiate the detection result. The differential value output by the load detection unit 81 is less than a predetermined threshold value (approximately 0) when the moving body 2 is stopped, and when the moving body 2 starts acceleration and the power consumption starts to increase. And when the power consumption starts decreasing at or above the threshold value (when the mobile body 2 stops acceleration and starts traveling at a constant speed, decelerates, or stops).
Furthermore, it becomes less than the threshold value.

The CPU 407 is also connected to the timer 406. The CPU 407 normally controls the reference value generation unit 403 to generate the first current command signal, determines whether the differential value output by the load detection unit 81 is equal to or more than the threshold value, and is equal to or more than the threshold value. When it becomes, it controls the reference value generation unit 403 to generate the second current command signal, then determines whether the differential value is less than the threshold value, and when it becomes less than the threshold value. Controls the current command generation unit 403 to generate a first current command signal when a predetermined time has elapsed by using a timer 406, and then the differential value is equal to or more than the threshold value. Determine whether or not

The current sensor 82 is the capacitor 42.
Although the current of c is detected, the output current of the inverter unit 401 or the output current of the rectifying / smoothing unit 400 may be detected as long as the current has a change corresponding to the change in the power consumption of the motor 24. . Further, instead of the current sensor, a voltage sensor may be used to detect the voltage having a change corresponding to the change in the power consumption of the motor 24 (the voltage of the capacitor 42c, the voltage output by the rectifying / smoothing unit 400, or the like). In addition, the impedance converter 402 is connected to the inductor 42.
a, 42b and the capacitor 42c, the inductors 42a, 42b and the capacitor 42c
May be arranged not only in the T-type but also in the π-type.
Further, the impedance conversion unit 402 may be configured by using two capacitors and one inductor, and the inductors and the capacitors may be arranged in π type or T type.
Also, one or more of the inductors may be configured by using a power supply line. Furthermore, the load detection unit 81 or the current sensor 82
May be provided inside the AC power supply 4 or outside the AC power supply 4. The other parts corresponding to those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 7 is a flow chart showing a procedure for supplying a constant current by the AC power source 4 provided in the contactless power feeding system. The CPU 407 has a current command generator 403.
To generate a first current command signal (S1).
At this time, the AC power supply 4 supplies the first constant current to the power supply line 40 by the action of the pulse width control unit 404 that has received the first current command signal. The current sensor 82 is the motor 24
The value of the current inside the AC power supply 4 corresponding to the power consumption of is detected (S2). Next, the load detection unit 81 detects the differential value of the detection result using the detection result of the current sensor 82 (S3).

The CPU 407 determines whether or not the differential value is greater than or equal to a predetermined threshold value (S4), and if it is less than the threshold value (NO in S4), the process returns to S2. When it is equal to or more than the threshold value (YES in S4), the current command generating unit 403 is controlled to generate the second current command signal (S5). At this time, the pulse width control unit 4 that has received the second current command signal
Due to the action of 04, the AC power supply 4 is first connected to the power supply line 40.
A second constant current larger than the constant current is supplied. Further, the current sensor 82 detects the value of the current inside the AC power supply 4 corresponding to the power consumption of the motor 24 (S6). Next, the load detection unit 81 uses the detection result of the current sensor 82 to detect the differential value of the detection result (S7).

The CPU 407 determines whether or not the differential value is less than a predetermined threshold value (S8).
(NO in step 8), the process returns to step S6. If it is less than the threshold value (YES in S8), the timer 406 is used to start measuring time (S9), and then it is determined whether or not a predetermined time has elapsed (S10). If it has passed (S
(YES in 10), the process is returned to S1, and the current command generator 4
03 is controlled to generate the first current command signal. If the predetermined time has not elapsed (NO in S10), S1
The processing is returned to 0 and the clocking is continued.

In the contactless power supply system as described above, the AC power supply 4 converts the power supplied from the commercial AC power supply 408 through the rectifying / smoothing unit 400 into the AC current by the inverter unit 401, and the AC current is impedance-converted. Based on the first current command signal generated by the current command generation unit 403 and the detection result of the current sensor 405, the pulse width control unit 404 causes the inverter unit 40 to convert the constant current into a constant current by the conversion unit 402.
By controlling 1, the first constant current is supplied to the power supply line 40. At this time, in the non-contact power feeding device 7, the resonance capacitor 5 receives the electric power induced in the pickup coil 51 by the magnetic flux generated around the power feeding line 40.
2 outputs a constant current, converts the constant current into a constant voltage, and further rectifies and smoothes it to the motor 24 through the power receiving unit 3
Supply power.

When the power consumption of the motor 24 increases (for example, when the moving body 2 starts accelerating), the output power to the motor 24 starts increasing in accordance with the increase in the power consumption, and the output power starts increasing. According to the current sensor 82
The detection result of will also start increasing. When the load detection unit 81 differentiates the detection result and the differential value becomes equal to or larger than a predetermined threshold value,
The AC power source 4 has a second voltage generated by the current command generator 403.
The pulse width control unit 404 controls the inverter unit 401 based on the current command signal and the detection result of the current sensor 405 to supply the second constant current to the power supply line 40. At this time, in the non-contact power feeding device 7, the second power larger than the first power is supplied to the motor 24.

Next, when the power consumption of the motor 24 starts to decrease (for example, when the moving body 2 finishes accelerating), the output power to the motor 24 starts to decrease according to the decrease of the power consumption, and As the output power decreases, the detection result of the current sensor 82 also starts to decrease. When the load detection unit 81 differentiates the detection result and the differential value becomes less than the predetermined threshold value, the AC power supply 4 causes the current command generation unit 403 to generate the first current command signal generated after the predetermined time has elapsed. And the pulse width control unit 404 based on the detection result of the current sensor 405.
Controls the inverter unit 401 to supply the first constant current to the power supply line 40. That is, during the supply of the first constant current, the load detection unit 81 and the current sensor 82 can be used to determine the timing at which the constant current to be supplied to the power supply line 40 is increased to become the second constant current. Therefore, by continuing the supply of the first constant current when the power consumption increases, the output voltage of the non-contact power supply device 7 becomes less than the minimum value of the allowable input voltage range of the device, and the protection circuit of the device operates to operate the motor. It is possible to prevent 24 from stopping.

During the supply of the second constant current, the load detection section 81, the current sensor 82, and the timer 406 are used to reduce the constant current to be supplied to the power supply line 40 to the first constant current. Because you can determine the timing,
By continuing the supply of the second constant current when the power consumption is reduced, it is possible to prevent an increase in power supply line loss and an increase in cost, and it is necessary to provide a large pickup core or a resonant capacitor. Absent. In addition, the load detection unit 81, the current sensor 82, and the timer 406.
Is provided on the side of the AC power supply 4, so that it is not necessary to provide the load detection unit 81, the current sensor 82, and the like on each moving body 2.

Further, since the differential value of the current corresponding to the increase / decrease of the power consumption is used to determine the increase / decrease of the power consumption by the increase / decrease of the differential value, for example, a complicated power consumption estimating circuit for estimating the total power of the power consumption Therefore, the device can be simply configured. Furthermore, when the second power is being supplied to the motor 24 and the power consumption of the motor 24 is rapidly reduced (for example, when the mobile body 2 is suddenly stopped), the motor 2
The output power for 4 sharply decreases as the power consumption decreases, and at the same time, the output voltage rapidly increases. When the output voltage is equal to or higher than the maximum value (reference voltage) of the input voltage allowable range of the contactless power supply device 7, the contactless power supply device 7
In the case where the output voltage limiting unit 6 provided in is operated, the same effect as that of the first embodiment can be obtained, and the control for reducing the power supply line current is not in time for a rapid decrease in power consumption. Even in this case, it is possible to prevent the device from being damaged due to an excessive increase in the output voltage.

When the CPU 407 controls the current command generator 403 to generate the second current command signal, the CPU 407 starts the time measurement using the timer 406, and when the predetermined time elapses, the first time The current command generator 403 may be controlled to generate the current command signal. That is, after increasing the power supply line current, the power supply line current may be decreased after a lapse of a predetermined time without detecting a decrease in power consumption.

(Third Embodiment) FIG. 8 is an electric circuit diagram showing a configuration of a non-contact power feeding device 7 according to a third embodiment of the present invention. The contactless power supply device 7 is provided in, for example, a contactless power supply system such as the contactless power supply system according to the first or second embodiment. The output voltage limiting unit 6 is the FET 6
8 and a rectifying section 61 using a diode bridge for rectifying an alternating current into a direct current having a full-wave rectified waveform, each provided in parallel with the resonance capacitor 52, and a choke coil 67 connected in series with the FET 68. Prepare for Also,
The output voltage limiting unit 6 includes a reference voltage generating unit 65 that generates a reference voltage and a comparing unit 64, and an input unit of the comparing unit 64 includes an output unit of the power receiving unit 3 (between the smoothing unit 33 and the motor 24). ) And the reference voltage generator 65 are connected to each other.

Further, the output voltage limiting section 6 is provided with a photocoupler 63 having a phototransistor 63a and a light emitting diode 63b.
3a and the comparison unit 64 is connected to the light emitting diode 63b, whereby the comparison unit 64 and the FET 68 are connected by the photocoupler 63. The comparison unit 64 compares the reference voltage generated by the reference voltage generation unit 65 with the output voltage output to the motor 24. When the output voltage becomes equal to or higher than the reference voltage, the comparison unit 64 outputs a predetermined current to the light emitting diode 63b of the photocoupler 63, and when the current is given, the light emitting diode 63b emits light and receives the light. An induced electromotive force is generated in the phototransistor 63a.
At this time, a voltage is applied to the FET 68, the direct current flows through the FET 68, and the FET 68 is turned on.
Further, the choke coil 67 dulls the direct current to limit (reduce) the transient peak current of the direct current.

Since the FET 68 is turned on,
The output of the rectification unit 61 is short-circuited, and the resonance capacitor 5 connected in parallel with the rectification unit 61 by the short-circuited output.
Both ends of 2 are shunted, the output voltage and the output current of the resonance circuit unit 5 become substantially 0, and power is not supplied to the power receiving unit 3. Therefore, the electric power stored in the smoothing unit 33 after being discharged is supplied to the motor 24, and the output voltage decreases.

When the output voltage decreases and becomes less than the reference voltage, the comparison unit 64 stops the output of the predetermined current to the light emitting diode 63b, and the light emitting diode 63b.
The light emission of b is stopped, the induced electromotive force is not generated in the phototransistor 63a, the direct current does not flow through the FET 68, and the FET 68 is in an off state. Therefore, the rectification unit 61 and the resonance capacitor 52 are not shunted. Contact power supply device 7
Supplies power to the motor 24 via the resonance circuit unit 5 and the power receiving unit 3. At this time, the discharged smooth portion 33 is charged,
The output voltage rises to a voltage corresponding to the output power. The other parts corresponding to those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As described above, the non-contact power feeding device 7 of the present embodiment can obtain the same effect as the non-contact power feeding device 7 according to the first or second embodiment. In addition, the rectifying unit 6
Since the output of 1 is the full-wave rectified waveform, the choke coil 67
However, since it functions as a current limiting means for suppressing the transient peak current flowing through the FET 68, the F of the first embodiment is
The device can be configured using the FET 68 smaller than the ET 62. In the present embodiment, it is preferable to use a choke coil as the current limiting means, but instead of the choke coil, for example, a resistor may be used as the current limiting means.

[0079]

According to the non-contact power supply device of the present invention, when the output voltage supplied to the load becomes higher than the reference voltage,
A shunt unit for shunting the power output by the pickup coil and the resonance capacitor is provided in parallel with the resonance capacitor, and a voltage corresponding to the reference voltage generated by the reference voltage generation unit and the output power supplied to the load (for example, the output In order to make a comparison with the voltage), the reference voltage generation unit and the output unit for connecting a load, for example, are connected to the input of the comparison unit. The shunt section is normally kept in the off state, and when the output voltage becomes equal to or higher than the reference voltage, the shunt section is turned on by the switching means, and the shunt section in the on state outputs the power output by the pickup coil and the resonance capacitor. Shunt. At this time, the electric power supplied from the pickup coil and the resonance capacitor to the impedance conversion unit becomes substantially zero, so that the output power does not exceed the reference voltage and rises, and conversely, the output voltage can be reduced. That is, when using the maximum input voltage of the input voltage permissible range of the device being fed from the device as the reference voltage,
It is possible to prevent damage to the device due to excessive output voltage.

Since the output voltage can be prevented from excessively rising by shunting the electric power output from the pickup coil and the resonance capacitor, the output voltage from no load to the maximum load can be prevented in order to prevent damage to the equipment. It is not necessary to use a large contactless power supply device including a component having an input voltage allowable range up to the output voltage, such as a pickup core having a large cross section or a large-capacity smoothing capacitor, and the device can be downsized. . Further, the pickup coil, the resonance capacitor, and the impedance conversion unit receive the constant current output from the pickup coil and the resonance capacitor, which is received by the pickup coil that is inductively coupled to the energized power supply line, and the impedance conversion unit outputs the constant current. Since it can be supplied to the load after being converted to a constant voltage with, it is not necessary to convert the constant current output by the resonance capacitor to a constant voltage with a shunt part using an FET, for example, and the output voltage is less than the reference voltage. In this case, the shunt part can be kept in the off state, and the power receiving efficiency is not deteriorated.

Further, when the comparison section detects that the output voltage supplied to the load becomes equal to or higher than the reference voltage, the light emitting element of the photocoupler is caused to emit light, and the light receiving element of the photocoupler receives the light, the shunt section. The shunt unit shunts the electric power output from the pickup coil and the resonance capacitor, makes the electric power output from the pickup coil and the resonance capacitor substantially zero, and reduces the output voltage. When the output voltage is less than the reference voltage, the comparison unit does not output the current to the photo coupler, and the photo coupler does not flow the current to the shunt unit. At this time, the shunt unit is turned off, and the power output from the pickup coil and the resonance capacitor is not shunted, so that the power is supplied from the pickup coil and the resonance capacitor to the impedance conversion unit. As a result, it is possible to efficiently limit the power receiving capacity of the pickup coil and prevent damage to the device being fed from the device due to an excessive increase in the output voltage without deteriorating the power receiving efficiency.

Further, using a rectifying section and a transistor which is turned on or off by the switching means,
The comparison unit is connected to the reference voltage generation unit and, for example, an output unit to which a load is connected, and the reference voltage generated by the reference voltage generation unit is compared with the output voltage supplied to the load.
Since the current flowing through the resonant capacitor is an alternating current, the rectifying section of the shunt section is provided in parallel with the resonant capacitor, and the transistor is provided in parallel with the rectifying section. Normally, the transistor is turned off,
When the output voltage exceeds the reference voltage, it is turned on by the switching means. The output of the rectifier is short-circuited using the transistor in the ON state, and the short-circuited output is
Shunts the electric power output by the pickup coil and the resonance capacitor. At this time, the electric power supplied from the pickup coil and the resonance capacitor to the impedance conversion unit becomes substantially zero, so that the output power does not exceed the reference voltage and rises, and conversely, the output voltage can be reduced.
That is, when the maximum input voltage within the allowable input voltage range of the device fed from the device is used as the reference voltage, damage to the device due to excessive output voltage can be prevented.

Further, by using, for example, a resistor as the current limiting means for reducing the current flowing through the shunt portion, the current flowing through the shunt portion is reduced and limited. In this case, since the shunt portion can be configured using a small-sized component having a current capacity corresponding to the limited current, the shunt portion can be downsized. Further, for example, when the shunt unit is configured by using the rectifying unit, the output of the rectifying unit is a full-wave rectified waveform, and thus the coil can be used as the current limiting unit. Further, when the current is limited by the full-wave rectified waveform, the coil can be made smaller than the resistor, so that the shunt portion can be further downsized.

According to the contactless power supply system of the present invention, the detector for detecting the current or the voltage is the current which changes in accordance with the change in the power consumption of the load (output power of the contactless power supply device). Alternatively, it is provided at an appropriate position inside the AC power supply or outside the AC power supply to detect a voltage (for example, a current that increases when the power consumption increases). When the current or voltage maintains a substantially constant value and then starts to increase or decrease, the power consumption starts to increase or decrease after the time when the current or voltage starts to increase or decrease. I understand that Therefore, the power detection unit can detect the time point when the power consumption starts to increase or the power consumption starts to decrease based on the detection result of the detector. At this time, the control means can adjust the power supply line current according to the change in the power consumption, so that the output voltage is too small.
It is possible to prevent the operation of the device from being stopped due to the activation of the protection circuit of the device that is supplied with power from the contactless power supply device.
It is possible to prevent the supply line loss from increasing and the cost to increase by continuing to supply the increased power supply line current.

When the power supply line current is increased when the power consumption is increased, the coil current flowing through the pickup coil provided in the contactless power supply device can be decreased.
Therefore, the heat generation of the coil can be reduced, and the magnetic flux density linked to the pickup coil can be reduced, so that the pickup core and the pickup coil can be downsized. Further, since the current (voltage) of the resonance capacitor provided in the contactless power supply device can be reduced, the resonance capacitor can be downsized. That is, the device can be downsized by increasing or decreasing the power supply line current according to the power consumption.
Furthermore, since a detector for detecting current or voltage can be provided in the AC power supply, it is not necessary to provide a detector for detecting power consumption in the mobile body.

Further, a current or a voltage related to the AC power supply is detected, an increase or decrease in the power consumed by the load is detected based on the differential value of the current or the voltage, and the feeder current is controlled according to the increase or the decrease in the power. Thus, for example, a well-known differentiating circuit is used as the power detector, and the current or voltage is differentiated by inputting the current or voltage signal detected by the detector to the power detector. When the differential value holds approximately 0 and then starts increasing or decreasing, it can be seen that the power consumption has started increasing or decreasing. That is, by detecting the time when the differential value starts to increase or decrease based on the detection result of the power detection unit, it is possible to detect the time when the power consumption starts to increase or the time when the power consumption starts to decrease. For this reason, with a simple configuration without performing complicated calculations,
It is possible to detect an increase or decrease in power consumption and efficiently adjust the power supply line current.

Further, the control means controls the current command generating means to normally generate a predetermined current command signal to supply the first current to the power supply line. When the current or voltage detected by the detector changes and it is detected that the power consumption of the load increases, the current command generating means is controlled to supply the second current larger than the first current to the power supply line. A predetermined current command signal is generated. In addition, when a predetermined time elapses from the time when the power consumption increases and the second current is supplied, or when the power consumption starts decreasing while the second current is being supplied, the first time measuring means is used. Supply current. As described above, the first current is normally supplied, the second current is supplied when the power consumption increases, and the first current is supplied again after an appropriate time when the power consumption decreases. The power supply line current can be efficiently adjusted according to the power consumption with a simple configuration without performing complicated calculation.

Further, by providing a means for controlling the power supply line current according to the change in the power consumed by the load and a means for limiting the output voltage supplied to the load to the reference value voltage or less, the power consumption is drastically increased. When the output voltage suddenly decreases and the output voltage suddenly increases, even if the output voltage cannot be decreased by suddenly decreasing the power supply line current, the contactless power supply device may be, for example, one of claims 1 to 3. When the output voltage output to the load exceeds the reference voltage by using the non-contact power supply device according to any one of the above, the resonance of the resonance capacitor is stopped and the power received by the pickup coil is supplied to the impedance conversion unit. In order to prevent the above and reduce the output voltage, the device fed from the non-contact power feeding device is
The present invention has excellent effects such as damage due to excessive output voltage can be prevented, and the same effects as those of the non-contact power supply line device can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a configuration of a mobile body system using a contactless power feeding system according to a first embodiment of the present invention.

FIG. 2 is a schematic side view showing a configuration of a moving body and a rail included in a moving body system using the contactless power feeding system according to the first embodiment of the present invention.

FIG. 3 is a schematic front view showing a configuration of a moving body and a rail included in the moving body system using the contactless power feeding system according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a power supply line and a pickup coil of the contactless power supply system according to the first embodiment of the present invention.

FIG. 5 is an electric circuit diagram showing the configuration of the non-contact power feeding device of the non-contact power feeding system according to the first embodiment of the present invention.

FIG. 6 is an electric circuit diagram showing a configuration of a contactless power feeding system according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure for supplying a constant current by an AC power supply included in the contactless power supply system according to Embodiment 2 of the present invention.

FIG. 8 is an electric circuit diagram showing a configuration of a non-contact power supply device according to a third embodiment of the present invention.

FIG. 9 is an electric circuit diagram showing a configuration of a conventional contactless power feeding system.

FIG. 10 is a graph showing the relationship between the output power and the output voltage of the contactless power supply device of the conventional contactless power supply system.

FIG. 11 is a graph showing the relationship between the output power and the output voltage of the contactless power supply device of the present invention.

FIG. 12 is a graph showing the relationship between the output voltage and output power of the contactless power supply device of the contactless power supply system of the present invention, the current inside the AC power supply corresponding to the output power, and the power supply line current.

FIG. 13 is a graph showing the relationship between the current inside the AC power supply corresponding to the output power of the contactless power supply device of the contactless power supply system of the present invention, the differential value of the current, and the power supply line current.

[Explanation of symbols]

24 motor 31 Impedance converter 4 AC power supply 40 power lines 406 timer 407 CPU 51 pickup coil 52 Resonant capacitor 6 Output voltage limiter 61 Rectifier 62,68 FET 63 Photo coupler 63a Phototransistor 63b light emitting diode 64 comparison section 65 Reference voltage generator 67 choke coil 7 Non-contact power supply device 81 Load detector 82 Current sensor

Continued front page    (72) Inventor Shingo Koyama             2-61, Jomi, Chuo-ku, Osaka-shi, Osaka             Tsubakimoto Chain Co., Ltd. F-term (reference) 5H105 AA09 BA03 BB07 CC02 CC19                       DD10 EE13

Claims (9)

[Claims] 1. A pickup coil and a resonance capacitor that convert a voltage induced in a pickup coil that is inductively coupled to a power supply line through which an alternating current flows into a constant current, and an impedance converter that converts the constant current into a constant voltage. In the non-contact power supply device for supplying output power to a load, a reference voltage generating unit for generating a reference voltage, the reference voltage,
A comparison unit that compares the output power with a voltage, and a switching unit that is turned on when the comparison unit detects that the voltage has become equal to or higher than the reference voltage. And a shunt portion provided in parallel with each other. 2. A photocoupler having a light emitting element and a light receiving element for receiving the light emitted by the light emitting element, wherein the switching means uses the light receiving element, and the shunt portion when the light receiving element receives the light. Is configured to be turned on, and the comparison unit is configured to cause the light emitting element to emit light when detecting that the voltage becomes equal to or higher than the reference voltage. The contactless power supply device according to. 3. The shunt unit includes a transistor that is turned on when the switching unit is turned on, and a rectification unit, and the rectification unit and the transistor are provided in parallel with the resonance capacitor. The non-contact power supply device according to claim 1, wherein the non-contact power supply device is provided. 4. The contactless power supply device according to claim 1, wherein the shunt portion has a current limiting unit that reduces a current flowing through the shunt portion. 5. The non-contact power supply device according to claim 4, wherein the current limiting unit includes a coil. 6. A contactless power supply system including a contactless power supply device which receives power from a power supply line through which an alternating current flows in a contactless manner and supplies power to a load, wherein detection is performed to detect a current or a voltage related to an AC power source connected to the power supply line. And a power detector that detects whether or not the power consumed by the load has changed based on a change in current or voltage detected by the detector, and the power detector detects the change in power. In this case, the non-contact power supply system is provided with a control unit that controls the AC power supply to supply current to the power supply line according to a change in the power. 7. The power detection unit detects whether or not the power has increased or decreased by differentiating a current or voltage signal detected by the detector.
The contactless power supply system described in. 8. A current command generating means for generating a plurality of current command signals, and a power supply means for receiving the current command signals and supplying a current of a magnitude corresponding to each of the current command signals to the power supply line. The control means controls the clocking means and the current command generating means to generate a current command signal so that the power feeding means supplies the first current; and the first current is supplied. A means for controlling the current command generating means to generate a current command signal so that the power feeding means supplies a second current larger than the first current when the increase in the power is detected; When the increase of the electric power is detected, or when the decrease of the electric power is detected after the increase of the electric power is detected, a means for starting the measurement of the elapsed time using the time measuring means, and the elapsed time When the specified elapsed time has passed The non-contact power supply system according to claim 6 or 7, further comprising: a unit that controls the current command generation unit to generate a current command signal so that the power supply unit supplies the first current. 9. The non-contact power supply device converts the voltage induced in a pickup coil inductively coupled to the power supply line into a constant current, a pickup capacitor and a resonance capacitor, and converts the constant current into a constant voltage. A reference voltage generation unit that includes an impedance conversion unit, supplies output power to a load, and that generates a reference voltage, a comparison unit that compares the reference voltage with a voltage corresponding to the output power, and
The shunt unit is provided in parallel with the resonance capacitor, the switching unit having an ON state when the comparison unit detects that the voltage becomes equal to or higher than the reference voltage. Item 9. The contactless power feeding system according to any one of Items 6 to 8.