JPH07298412A - Overload protector of ground propulsion coil of linear motor railway - Google Patents

Abstract

PURPOSE:To protect a ground propulsion coil and improve the reliability by installing an overload protector, in the power supply system to the ground proplusion coil of a linear motor railway. CONSTITUTION:This is provided with an overload protector 1 composed of a timer 1a, an integrator 1b, an operator 1c, a memory 1d, a comparator 1e, and a variable frequency power unit controller 1f, and it seeks given load from the time and current applied to a group of propulsion coils 5, and stops the operation of a variable frequency power unit when this value gets over the stipulated value for judging the overload condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overload protection device in a linear motor railway for the purpose of protecting a ground propulsion coil as an armature of a linear motor from damage due to overload and improving reliability.

[0002]

2. Description of the Related Art As shown in Japanese Patent No. 979735 "Linear motor power feeding device", a driving system of a linear motor railway is synchronized with a train position transmitted from a train position detecting device, and is used in a section where a train is located. This is a method of turning on the switchgear and supplying power from the variable frequency power supply to the ground propulsion coils belonging to that section. That is, the energization to the ground propulsion coil group, which is the armature of the linear motor, is the power supply to the section unit where the train is located.

A known example of a method for preventing overcurrent of a linear motor is as shown in Japanese Patent Application No. 62-268918 "Control circuit for linear motor electric vehicle".
By detecting the rate of change of the voltage supplied to the linear motor with time, a precursor phenomenon leading to an overcurrent is detected, thereby reducing the output voltage from the inverter device to the linear motor coil, and preventing an overcurrent.

[0004]

As described above, the ground propulsion coil is a coil that is energized only when the train is in the section to which the ground propulsion coil belongs, and its rating is a short-time rating. There is. Therefore, if the ground propulsion coil is continuously energized for a long period of time, it is conceivable that the coil body will be burned due to the heat generation.

Even when the train is not continuously energized, the linear motor railway having the above-described structure is energized again when the next train passes through the section where one train passed, so the ground propulsion coil is repeatedly energized in a short time. It is conceivable that burnout will occur due to the accumulated heat.

[0006] The ground propulsion coil is normally rated to withstand the required short-time and long-time energization when the entire system is normal. When the vehicle is moved, the braking force cancels the propulsive force, a larger current is required than in normal traveling, and the energization time to a predetermined section becomes long.

Similarly, when the on-vehicle field (superconducting magnet) causes a failure such as multiple quenches, the propulsive force is insufficient due to the attraction of the magnets and the reduction of the repulsive force, so that the current supplied to the ground propulsion coil increases. .

Further, even if the system is normal, it is considered that the cumulative amount of heat generated by passing a plurality of trains many times becomes a problem as described above.

The present invention has been made in view of such circumstances, and an overload of a ground propulsion coil of a linear motor railway which solves the above problems and protects the ground propulsion coil and improves reliability is provided. The purpose is to provide a protection device.

[0010]

An overload protection device for a ground propulsion coil of a linear motor railway according to the present invention is a ground propulsion device for dividing a power supply range of a ground propulsion coil which is an armature of a linear motor of a linear motor railway. The coil group is divided into a number of sections, each section is provided with a switchgear to supply or cut off the energizing current, and the variable frequency power supply supplies power to the ground propulsion coil group of the desired section via these switchgear. In the system, a closing time measuring means for measuring a closing time of each switching device provided corresponding to each section, an integrating means for integrating a current value of an output current of the variable frequency power supply device, and a closing time measurement. Calculating means for calculating the load of the ground propulsion coil group belonging to each section based on the measured output of the means and the integrated output of the integrating means; A storage unit that stores the calculation output of the calculation unit for each section, and a calculation result of the load of the ground propulsion coil group belonging to each section stored in the storage unit and a specified value for determining an overload state are provided. Comparing means for comparing and a variable frequency power supply device for supplying to the group of ground propulsion coils belonging to the corresponding section when the product of current and time applied to the ground propulsion coil based on the comparison output of the comparison means exceeds a specified value. And a control means for controlling the output of the variable frequency power supply so as to narrow the output current.

Further, the overload protection device for the ground propulsion coil of the linear motor railway according to the present invention has a large number of ground propulsion coil groups for dividing the power supply range of the ground propulsion coil which is the armature of the linear motor of the linear motor railway. In a system divided into sections, each section is provided with a switchgear for supplying or cutting off a current, and a variable frequency power supply supplies power to the ground propulsion coil group of a desired section through these switchgear, A closing time measuring means for measuring a closing time of each switchgear provided corresponding to each section, an integrating means for integrating a current value of an output current of the variable frequency power supply device, and a ground propulsion coil group belonging to each section. The first temperature characteristic is stored in advance when the temperature of each section rises and falls when power is turned on or off. Storage means, based on the integrated output of the measurement output and integrating means of the closing time measuring means, said first
And a calculation means for calculating the temperature of each section in a predetermined cycle with reference to the temperature characteristics stored in the storage means, and for obtaining a temperature increase when the ground propulsion coil is energized and a temperature decrease when the energization is stopped. A second storage means for storing the calculation output of the calculation means for each section; and a calculation result of the temperature when the temperature of each section stored in the second storage means rises and an allowable limit of the temperature rise. Based on the comparison output of the comparing means for comparing with the upper limit value shown, it is determined whether or not the temperature rise of the ground propulsion coil when repeatedly energized exceeds the upper limit value, and the upper limit value is exceeded. And a control means for controlling the output of the variable frequency power supply so as to narrow down the output current of the variable frequency power supply supplied to the ground propulsion coil group belonging to the corresponding section. And butterflies.

[0012]

The overload protection device for the ground propulsion coil of the linear motor railway configured as described above determines the energization time to the ground propulsion coil from the closed state of the switchgear for each section, and outputs the variable frequency power supply device at this time. The current is integrated and the load applied to the ground propulsion coil is calculated from the product of current and time. If this value exceeds the specified value, the variable frequency power supply is stopped.

In the overload protection device for the ground propulsion coil of the linear motor railway having the above structure, the temperature rise due to the heat dissipation coefficient when the ground propulsion coil is energized and the temperature decrease due to the heat dissipation coefficient when the energization is stopped are constantly calculated, Find the temperature of the ground propulsion coil for each section. When this value exceeds the upper limit value indicating the allowable limit of temperature rise, the output current of the variable frequency power supply device is controlled to be narrowed down.

As described above, the ground propulsion coil is protected and the reliability is improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

First, referring to FIG. 2, a power supply system for a linear motor railway will be described. In the system to which this method is applied, the ground propulsion coil, which is the armature of the linear motor, is divided into a certain unit of coil group (LMn-3 to LMn + 3), and the current from the variable frequency power supply device is divided into sections. There are provided feeder section switchgear (SWn-3 to SWn + 3) for supplying and shutting off.

The energization of the ground propulsion coil is performed by synchronizing only with the current position of the train and turning on only the switchgear corresponding to the section where the train is located. In other words, power is supplied to the ground propulsion coil only to the ground propulsion coil belonging to the section where the train is located. In the present invention, reference numeral SWn
-3 to SWn + 3, the loading / unloading state of the feeder section switchgear is taken in, the closing time is counted for each feeder section switchgear, and the time of energization for each section indicated by the symbols LMn-3 to LMn + 3 The load applied to the ground propulsion coil is calculated from the current, and when the calculated value of this load exceeds the specified value for judging the overload condition, the output current of the variable frequency power supply device is narrowed down to operate the variable frequency power supply device. Is to stop.

FIG. 1 shows the construction of an embodiment of an overload protection device for a ground propulsion coil according to the present invention. In the figure, the drive control device 2 fetches the train position information 6a from the train position detection device 6 and instructs the feeder distribution switchgear 4 of the section synchronized with this position to supply the feeder distribution switch 2
Output c.

Further, the drive control device 2 outputs to the variable frequency power supply device 3 an output current command value 2a and a phase command value 2b for controlling the train to a target speed. The variable frequency power supply device 3 outputs the output current 3 according to the instructed value.
a is output to the ground propulsion coil group 5.

On the other hand, the overload protection device 1 for protecting the ground propulsion coil includes a time measuring device 1a, an integrator 1b, a computing device 1c, a memory 1d, a comparator 1e, and a variable frequency power supply device controller 1f. It consists of and.

The time measuring device 1a fetches the feeding / opening state information 4a of the feeder section switch from the drive control device 2 and counts the time during which the feeder section switch 4 is turned on. Further, the integrator 1b fetches the output current value information 3b from the variable frequency power supply device 3 and obtains the output current value while the feeder section switchgear 4 is turned on. The time and current value obtained above become the time and current when the ground propulsion coil is energized. The load applied to the ground propulsion coil is calculated by the calculator 1c from the time and the current value. This calculation is performed for each section which is a unit for energizing the ground propulsion coil, and the calculation result is stored in the memory 1d.

The comparator 1e compares the calculation result of the load of the ground propulsion coil group belonging to each section, which is obtained by the calculation unit 1c, with a predetermined value for judging the overload state, and the calculation result is obtained. If it exceeds the specified value, the variable frequency power supply controller 1f outputs a variable frequency power supply stop command 1g to the variable frequency power supply 3 to stop the variable frequency power supply 3.

The contents of the calculation executed by the calculator 1c are as follows.
The load, that is, the amount of heat generated is calculated for each section based on the current-time product.

Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of the overload protection device according to this embodiment is basically the same as that of FIG.
The functions of c, the memory 1d, and the comparator 1e are different. That is, in the present embodiment, the temperature increase when the ground propulsion coil is energized and the temperature decrease due to the heat dissipation coefficient when the energization is stopped are constantly calculated to obtain the temperature of the ground propulsion coil for each section. When this value exceeds the upper limit value indicating the allowable limit of temperature rise, the output current of the variable frequency power supply device is controlled to be narrowed down. Therefore, the calculation content of the arithmetic unit 1c, the storage content of the memory 1d, and the comparison target of the comparator 1e are different. Hereinafter, the contents of this embodiment will be specifically described.

FIG. 3 shows a temperature rise curve when a continuous maximum allowable current I ₀ is applied to the ground propulsion coil, which is an armature of a linear motor, and a current is supplied to the ground propulsion coil after the temperature becomes saturated. The temperature fall curve when stopped is shown.
In the figure, the curves when the temperature rises and when the temperature falls can be expressed by equations (1) and (2), respectively.

[0026]

[Equation 1]

[0027]

[Equation 2]

Here, τ is a temperature rise value, τ _e is an allowable maximum temperature rise value (saturation temperature), Ts is a thermal time constant, and t is an elapsed time.

The maximum allowable temperature rise value τ _e is expressed by the following equation (3).

[0030]

[Equation 3]

Here, K is a heat radiation coefficient, A is a heat radiation area, and Q is a heat quantity. Since the heat quantity Q is the energy supplied during a unit time and is proportional to the square of the current, the equation (3) can be rewritten as the following equation.

[0032]

[Equation 4]

Here, K ₁ and K ₂ are constants, and K ₂ = K ₁ /
It is KA. In this embodiment, assuming that the upper limit value Ks for determining the limit of temperature rise is the temperature at 2Ts, which is twice the thermal time constant, the ratio to the maximum allowable temperature rise value τ _e is shown in FIG. As is clear from, Ks = 0.86τ _e .

Next, the temperature rise characteristics when current is supplied to the ground propulsion coil and the temperature decrease characteristics when current supply is stopped will be described more specifically. FIG. 4A shows the temperature rise characteristics when the continuous maximum allowable current I ₀ is flowing and when the thermal equivalent current im is flowing. Since the temperature rise value is proportional to the square of the current, the temperature rise value τ _e when the continuous allowable maximum current I ₀ is flowing and the temperature rise value τ _es when the thermal equivalent current im is flowing are expressed by the following equation ( It can be represented by 5) and (6).

[0035]

[Equation 5]

[0036]

[Equation 6]

Therefore, the temperature rise values τ _e1 and τ _e2 at the time when time t has elapsed from the time when the current started to flow in the ground propulsion coil are expressed by the following equations (7) and (8).

[0038]

[Equation 7]

[0039]

[Equation 8]

Therefore, the temperature rise value τ _e2 and the temperature rise value τ
the ratio τ _e2 / τ _e1 with _e1,

[0041]

[Equation 9]

In addition,

[0043]

[Equation 10]

Here, ts is a calculation cycle, and i is a current value flowing in the ground propulsion coil at the time of calculation. The formula (10) is the formula (1
It can be rewritten as in 1).

[0045]

[Equation 11]

Therefore, the temperature rise value τ _e2 at the time point when the time t has passed from the time point when the current starts to flow in the ground propulsion coil is _calculated from the equations (9) and (11).

[0047]

[Equation 12]

It becomes Here, τ _e1 is the temperature at time t after the continuous maximum allowable current I ₀ is started to flow through the ground propulsion coil. If the continuous maximum allowable current I ₀ and the thermal time constant Ts are known in advance by measurement, the temperature rise value τ
_{From the} exponential function table shown in FIG. 5, _e1 can be known as a ratio of what% of the maximum allowable temperature rise value τ _e . If the maximum allowable temperature rise τ _e is known, the temperature rise τ _e1 itself can be _calculated .

Next, when the current is supplied to the ground propulsion coil after the current supply is stopped and the amount of heat remains in the ground propulsion coil, the temperature rise value τ _e2 after the elapsed time Σts is It is obtained as shown in FIG. That is, the initial value τ of the temperature rise value of the ground propulsion coil
Assuming that _ex is known, the time t _m required for the temperature of the ground propulsion coil to rise up to the temperature τ _ex is shown in FIG.
It can be obtained from the exponential function table shown in. The time t _m is the time required from the temperature rise value 0 at the point P to the temperature rise value at the point Q in FIG. 4B.

Therefore, assuming that the time from the temperature τ _ex to the temperature at the point R after elapse of the time of Σ ts starts from the point P of the temperature rise value 0 and the time t _m + Σts has elapsed, the equation (12) Can be asked to return to.

Next, FIG. 4 (c) shows a case in which the current supply is stopped after a certain time has passed from the time when the current flows through the ground propulsion coil, and then the current supply is repeated after a certain time has elapsed. It will be described with reference to FIG. As shown in the figure, the temperature τ _ey at which the current is flowing in the ground propulsion coil is reached, the current supply is stopped at this time, and the temperature τ _ex at the time when Σts has elapsed can be obtained as follows. it can. That is, since the temperature τ _ey is known, the time t _X for going back to the past and processing from the maximum allowable temperature rise value τ _e to the temperature τ _ey can be obtained from the exponential function table shown in FIG. Therefore, it is assumed that the temperature τ _ex when the time Σts has elapsed from the time when the temperature τ _ey is reached is the time t _X + Σts that has elapsed from the time t _i when the temperature is the allowable maximum temperature rise value τ _e . It can be obtained from the exponential function table.

Incidentally, in FIG. 5, the curve M is an exponential curve showing the temperature rise characteristic and the curve N is the exponential curve.

In the present embodiment, the temperature rise is obtained by the calculator 1c from the heat generation amount of the ground propulsion coil when energized for each section and the heat radiation amount when the energization is stopped by the method described above.

In this embodiment, the memory 1d is provided with a (current) ² · time product table and an elapsed time table shown in FIG. 6 for each section, and an X file shown in FIG. 7 as a file common to each section. The Y file and the Z file are provided, and a section temperature table and an exponential function table are common tables for each section.

Here, the X file is a file showing the correspondence relationship between the initial temperature value τ _ex and the time t _m , and the Y file is τ _e −τ _ey = A and the correspondence relationship between the temperature difference A and the time t _X is shown. The Z file is a file showing the correspondence relationship between the elapsed time B and the temperature τ _ex with t _X + Σts = B. The section temperature table is a table for setting the temperature rise value τ _e2 of each section. The exponential function table stores the contents shown in FIG. 5 as a table.

Next, the operation of the overload protection device according to this embodiment will be described with reference to FIG. In the figure, the drive control device 2 fetches train position information from the train position detection device 6,
Select the corresponding section, and through the feeder switchgear 4 corresponding to the selected section, the variable frequency power supply 3
More current is supplied to the ground propulsion coils in the above section (steps 20 and 21). Next, the computing unit 1c takes in the outputs of the time measuring unit 1a and the integrator 1b, and calculates the temperature rise value τ _e2 of the ground propulsion coil group belonging to the relevant section (step 22). This temperature rise value (temperature fall value) τ _e2 is shown in FIGS. 5 and 6 according to the heat generation state of each section.
Also, the data of each table and each file shown in FIG. 7 are read from the memory 1d and calculated by the method described above to obtain the data.

Further, the temperature rise value (temperature fall value) τ _e2 obtained by the computing unit 1c is stored in the memory 1d, and this temperature value τ _e2 is the upper limit value Ks for judging the limit of the temperature rise by the comparator 1e. Is compared (step 23). If τ _e2 <Ks, the selected section is not in the overheated state, and the processing is terminated as it is.

If τ _e2 ≧ Ks, the selected section is in an overheated state, so abnormal processing due to overheating is performed. For example, it is controlled by the variable frequency power supply controller 1f to stop the operation of the variable frequency power supply so as to stop the current supply to the ground propulsion coil belonging to the section (step 24).

[0059]

As described above, according to the present invention,
Since it is possible to prevent an excessive load or an overheated state on the ground propulsion coil, it is possible to improve reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an overload protection device for a ground propulsion coil according to the present invention.

FIG. 2 is an explanatory diagram showing a power feeding system of a linear motor railway.

FIG. 3 shows a temperature rise curve when a continuous maximum allowable current I ₀ is applied to the ground propulsion coil and a temperature fall curve when the current supply to the ground propulsion coil is stopped after the temperature is saturated. It is a characteristic diagram.

FIG. 4 is an explanatory diagram more specifically showing temperature rise characteristics when current is supplied to the ground propulsion coil and temperature decrease characteristics when current supply is stopped.

FIG. 5 is a diagram showing the contents of an exponential function table used for calculating the temperature of the ground propulsion coil.

FIG. 6 is an explanatory diagram showing contents of a table provided for each section.

FIG. 7 is an explanatory diagram showing contents of files and tables commonly used for each section.

FIG. 8 is a flowchart showing the operation contents of another embodiment of the overload protection device for a ground propulsion coil according to the present invention.

[Explanation of Codes] 1 overload protection device 1a time measuring device 1b integrator 1c computing unit 1d memory 1e comparator 1f variable frequency power supply device controller 1g variable frequency power supply device start / stop command 2 drive control device, 2a output current command Value 2b Phase command value 2c Feeding section switch open / close command 3 Variable frequency power supply 3a Output current 3b Output current value information 4 Feeding section switch 4a Feeding section switch open / closed state 5 Ground propulsion coil group 6 Trains Position detection device 6a Train position information

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeki Koike 1070 Imomo, Katsuta City, Ibaraki Prefecture, Hitachi Ltd. Mito Plant (72) Inventor Masayuki Takayama 1070 Imoge, Katsuta City, Ibaraki Hitachi Ltd. Mito Plant, Ltd. Within

Claims (2)

[Claims] 1. A group of ground propulsion coils is divided into a plurality of sections in order to divide a power supply range of a ground propulsion coil which is an armature of a linear motor of a linear motor railway, and an energizing current is supplied or cut off for each section. In a system in which a switching device for power supply to a ground propulsion coil group of a desired section is supplied by a variable frequency power supply through these switching devices, the closing time of each switching device provided corresponding to each section is measured. Input time measuring means, integrating means for integrating the current value of the output current of the variable frequency power supply device, and ground propulsion coil group belonging to each section based on the measured output of the input time measuring means and the integrated output of the integrating means. Calculating means for calculating the load, storage means for storing the calculation output of the calculating means for each section, and Comparing means for comparing the calculation result of the load of the ground propulsion coil group belonging to each section and the specified value for judging the overload state, and energizing the ground propulsion coil based on the comparison output of the comparison means. Control means for controlling the output of the variable frequency power supply device so as to narrow down the output current of the variable frequency power supply device supplied to the ground propulsion coil group belonging to the relevant section when the current-time product exceeds the specified value. An overload protection device for a ground propulsion coil of a linear motor railway, which is characterized in that 2. The ground propulsion coil group is divided into a plurality of sections in order to divide the power supply range of the ground propulsion coil, which is an armature of a linear motor of a linear motor railway, and the energizing current is supplied or cut off for each section. In a system in which a switching device for power supply to a ground propulsion coil group of a desired section is supplied by a variable frequency power supply through these switching devices, the closing time of each switching device provided corresponding to each section is measured. Turning-on time measuring means, integrating means for integrating the current value of the output current of the variable frequency power supply device, and temperature rise and temperature of each section when energizing or de-energizing the ground propulsion coil group belonging to each section The product of the first storage means in which the temperature characteristic at the time of falling is stored in advance, the measurement output of the charging time measurement means and the integration means. Based on the output, the temperature of each section is calculated in a predetermined cycle by referring to the temperature characteristics stored in the first storage means, and the temperature rise when the ground propulsion coil is energized and when the energization is stopped Calculation means for obtaining a temperature decrease, second storage means for storing the calculation output of the calculation means for each section, and calculation result of the temperature when the temperature of each section rises stored in the second storage means And comparing means for comparing the upper limit value indicating the allowable limit of temperature rise, and it is determined based on the comparison output of the comparing means whether or not the temperature rise of the ground propulsion coil when repeatedly energized exceeds the upper limit value. Then, when the upper limit value is exceeded, the output of the variable frequency power supply device is controlled so that the output current of the variable frequency power supply device supplied to the ground propulsion coil group belonging to the relevant section is narrowed down. An overload protection device for a ground propulsion coil of a linear motor railway, which has a control means.