JP4945313B2 - Regenerative resistance fault judgment system - Google Patents

Description

  The present invention relates to an electric hoisting machine, a trolley device, and a saddle device that perform rotation speed control with a frequency converter and perform processing of regenerative electric power with a regenerative resistor.

  As a device for protecting a regenerative resistor, Japanese Patent Application Laid-Open No. 5-336758 discloses a protection resistor for a regenerative resistor when a switch power semiconductor fails as a known example of an inverter.

JP-A-5-336758

  A problem to be solved by the present invention will be described with reference to FIG. 1 in Japanese Patent Laid-Open No. 5-336758. In the inverter regenerative resistance protection device described in the patent document, when the fuse 5 attached for protection deteriorates due to the inrush current of the regenerative current or is disconnected, or when the thyristor switch 6 is short-circuited, the fuse 5 is blown or regenerated. When the disconnection due to the deterioration of 4 occurs, the regenerative power cannot be normally consumed in the regenerative circuit unit 7. That is, during the regenerative operation of the electric motor 10, the regenerative energy cannot be consumed, the voltage VDC of the rectifier 1 of the inverter device rises, an overvoltage protection operation occurs, and the operation stops.

  This can be wound in an electric hoist, but cannot be wound. In the trolley device and the saddle device, the electric motor suddenly stops at the deceleration portion. Some operations could not be performed until the parts were replaced, and there was a lack of consideration in the countermeasures after the protection occurred.

The present invention is to provide above-mentioned problems by the electric hoist, trolley equipment, early detection regenerative resistance failure of the saddle device, an inverter regenerative resistor fault decisions system for preventing to become completely inoperable is there.

  In order to solve the problems according to the present invention, a description will be given with reference to FIG. In the present invention, the regenerative resistor is composed of a plurality of resistors 11 to 15 in parallel, and the regenerative resistor failure determination circuit 16 is configured by combining with the current detector 3 that detects the regenerative current value flowing through the entire regenerative resistor. . With this configuration, the number of stepwise resistance breaks is determined according to the current value. In this circuit diagram, five regenerative resistors are shown, but any number of regenerative resistors may be used.

The information obtained from the regenerative resistance failure judgment circuit 16 is achieved by means for taking in the control unit that performs frequency control and performing control to lower the frequency of the frequency converter in accordance with the current value.
The regenerative resistance failure judging means and means comprising a display device, a speaker device, a vibration generating device and the like are provided.

According to the regenerative resistance fault determination system of the present invention, when one of the regenerative resistors configured in parallel is disconnected, a change in the regenerative current value corresponding to the increase in the combined resistance value is detected by the current detector, and the control unit By taking in and performing control to lower the frequency control of the frequency converter, further disconnection of the regenerative resistor can be prevented. As a result, the hoisting machine can avoid a stop, so that an emergency lowering operation can be performed.

  Furthermore, it is possible to notify the disconnection state to the outside by notifying immediately by display or sound, vibration, etc., and it is possible to replace the regenerative resistor before the frequency converter is completely stopped. Furthermore, since the number of failures is known in advance, there is no waste in preparing parts. In addition, since overhead cranes are high-place work, the work required is minimal, so the work time can be shortened and safety can be improved.

  In addition, effects such as simplification of the circuit protection device can be obtained.

  First, the overall configuration and operation status of the inverter crane apparatus will be described with reference to FIGS. In FIG. 3, crane saddle devices 17 and 30 move the electric hoisting machine 23 and the trolley device 20 incorporated in the girder in the e direction or the f direction on the saddle rail by the saddle electric motors 18 and 31. The saddle motors 18 and 31 are controlled to have necessary frequency, voltage, and current characteristics by an instruction from the operation input device 27 and the saddle frequency converter 28.

  The trolley device 20 uses the trolley motor 19 to move the electric hoisting machine 23 in the c direction or the d direction along the girder. The trolley motor 19 is controlled to have necessary frequency, voltage, and current characteristics by an instruction from the operation input device 27 and a trolley frequency converter 29.

  The electric hoisting machine 23 moves the load in the a direction or the b direction by the hoisting electric motor 24. The hoisting motor 24 is controlled to have necessary frequency, voltage, and current characteristics by an instruction from the operation input device 27 and the hoisting frequency converter 21.

  This inverter type crane device is moved in the e and f directions of the crane saddle devices 17 and 30 by the operation instruction from the operation input device 27, moved in the c and d directions by the trolley device 20, and the electric hoisting machine 23. The movements in the directions a and b can be processed in parallel.

  FIG. 4 shows the operation pattern during operation of the trolley device, crane saddle device, and electric hoist. In each operation pattern shown in FIG. 4, the hatched portion is a portion that generates regenerative energy. When the crane saddle devices 17, 30 and the trolley device 20 decelerate from running, the electric hoist 23 is when unwinding. This applies when decelerating from the hoist.

  The regenerative energy is generated by the saddle regenerative resistance device 29 for the generation of the saddle motors 18 and 31, the regenerative resistance device 26 for the trolley motor 19, and the regenerative resistance for winding by the regenerative resistance device 26 for the hoisting motor 24. It is converted into heat energy by the device 22 and processed.

  The frequency converters 21, 25, and 28 and the regenerative resistance devices 22, 26, and 29 are separately mounted for hoisting, trolley, and saddle, but the regenerative resistance devices for hoisting and trolley are shared. Then, the arrangement may be combined.

  Hereinafter, the present invention will be described with reference to FIG. 4, FIG. 5, FIG. 6, and FIG.

  FIG. 5 shows a block diagram of an electric hoist using the frequency converter of the present invention. When the operation input device 27 gives a driving command for winding up or down the load, the signal is taken into the control device 34. The control device 34 controls the frequency conversion device 33 and the brake device 35 based on information from the operation input device 27 to vary the rotation speed of the hoisting motor 24 continuously or stepwise. A regenerative current flows through the regenerative resistors 11 to 15 in the following state. That is, it is a portion indicated by oblique lines in the electric hoisting machine pattern shown in FIG.

  The regenerative energy generated when the hoisting motor 24 generates a power generation phenomenon during lowering and deceleration increases the regenerative voltage between the hoisting motor 24 and the frequency converter 33 (between the VDC of the rectifier 1 in FIG. 2). Voltage), and when the voltage rise is detected, the control unit 34 controls energization (turns on the power switch semiconductor 2 in FIG. 2), flows as a regenerative current to the regenerative resistors 11-15, and converts it into heat energy. It is processed.

  Next, in describing the regenerative current detection method, first, a change in regenerative current when a plurality of regenerative resistors are disconnected from the normal time will be described. In order to make it easy to explain the regenerative currents flowing through the plurality of regenerative resistors shown in FIG. 5, the resistors 11 to 15 are set to 100 (Ω), and the regenerative device operating point voltage VDC = 350 (V). In addition, FIG. 6 shows a graph showing the change in the regenerative current value so that the change rate can be easily understood.

If the current that flows when all five are energized is the regenerative current I1,
Regenerative current I1 = Regenerative operating voltage / Regenerative resistance total value (5)
= 350 ÷ (100 ÷ 5) = 17.5 (A)
It becomes.

Here, if the current that flows when the resistor 11 is cut is the regenerative current I2,
Regenerative current I2 = Regenerative operating voltage / Regenerative resistance total value (4)
= 350 ÷ (100 ÷ 4) = 14.0 (A)
Current decrease rate = (17.5-14.0) ÷ 17.5 = 0.2
= 20 (%)
Similarly, it is determined that the current reduction rate is 40 (%) when the two are cut, and the current reduction rate is 60 (%) when the three are cut and the current reduction rate is 80 (%) when the four are cut. As described above, if the regenerative current value is always measured on the basis of the normal regenerative current value and the decrease rate is obtained, it is possible to determine the resistance shortage step by step.

Next, the reason why the output frequency of the frequency converter is controlled according to the resistance shortage will be described. As described above, when the regenerative resistor is disconnected, the combined resistance value increases and the regenerative current does not flow. However, since the regenerative power due to the counter electromotive force of the hoisting motor 24 does not change, the regenerative power cannot be consumed, so that the voltage between the VDCs increases, and a means for preventing this causes the lowering frequency of the motor to I have to lower it. Here, the electromotive force P of the motor is: electromotive force P (W) = torque T × rotational speed ω
It is represented by Assuming that the torque T is a force drawn below when the motor is lowered, the weight of the load does not change when the motor is lowered. Therefore, it can be understood that the electromotive force P decreases in direct proportion to the decrease in the rotational speed ω. Here, since the total power capacity of the resistors is 4/5, the electromotive force P must be reduced to 4/5 in proportion. In this case, since the rotational speed and the electromotive force are proportional, the rotational speed may be reduced by 20%. Similarly, the speed is reduced by 40% for two cuts, 60% for three cuts, and 80% for four cuts.

  By controlling the output frequency of the frequency converter according to the regenerative resistance being cut in this way, the object is to always keep the load factor of the resistance below a certain level and prevent the resistance from being cut.

  The operation of controlling the frequency converter 33 and the display device 36 by taking this stepwise current change from the regenerative resistance failure judgment circuit 16 to the control device 34 will be described with reference to the flowchart of FIG.

  In the regenerative current value measurement process a, the control device 34 takes in the regenerative current value during the regenerative operation from the current detector 3. In the regenerative current value change calculation process b, the rate of change is calculated from the current value based on the current value of the normal state stored in advance. When the regenerative resistor is not disconnected at all, the decrease rate is 0%. Therefore, the process proceeds to No in the branch point process c, and the process proceeds to the regenerative current value measurement process a again and repeats again.

  When one of the regenerative resistors is cut, the current value acquired in the regenerative current value measurement process a is calculated as 20% decrease in the regenerative current value change calculation process b (see the above regenerative current value decrease rate calculation). Therefore, the process proceeds to the Yes side in the branch process c, and proceeds to Yes in the branch process d. For example, a combination of lighting and blinking using red, yellow, green lamps, etc. as a display example (determining how many times blinking is a combination of one-second lighting, one-second light-off, one cycle and then five-second light-off). When one regenerative resistor has expired, a red light indicates a failure, a yellow flashing three times indicates a regenerative resistance failure, and a green one blink indicates that one regenerative resistor has expired. Then, the control device 34 gives an instruction to lower the winding speed by 20% to the frequency conversion device 33, and the process proceeds to the processing a.

  If two regenerative resistors are cut off, the process proceeds to the Yes side in the branching process e as well, and the display device 36 now turns on the red lamp, blinks the yellow lamp three times, blinks the green lamp twice, and regenerates resistance 2 Notify that the book has run out, and control to lower the number of rotations by 40%.

  In the embodiment, when three regenerative resistors are cut, the branch process f is skipped and the lowering rotation frequency is lowered by 60%. If four pieces are cut, the branching process g is skipped, and the lowering rotation frequency is lowered to 80%. When the five regenerative resistors are disconnected, the regenerative power cannot be consumed. However, in order to prevent an increase in the voltage between VDCs, the frequency converter is suppressed to a frequency at which no regenerative power is generated so that it can be used as soon as possible.

  By operating in this way, when the regenerative resistance of the electric hoist is cut off, the external hoist is informed, the electric hoist is prevented from being completely stopped, and the hoisting operation etc. can be performed quickly. Can do. In addition, it is possible to replace the regenerative resistor that has been cut before the complete stop.

  In this embodiment, the display is used as means for notifying the outside of the resistance breakage, but sound, vibration, etc. may be used as described in the item of means to solve. Although the number of regenerative resistors is five, any number may be used as long as it is plural, and the number of regenerative resistors may be changed so as to increase / decrease the amount of reduction in the lowering rotation speed of the frequency converter in the flowchart according to the use situation. .

  This regenerative resistance failure determination means can be used for the trolley device or saddle device of the inverter type crane device shown in FIG. 3, and is effective in preventing a sudden stop during deceleration.

It is a circuit diagram which shows a well-known regenerative resistance protection and an inverter apparatus. It is a circuit diagram which shows the regeneration circuit apparatus and inverter apparatus of this invention. It is a perspective view which shows the whole structure of an inverter type crane apparatus. It is an operation pattern and regenerative current conduction pattern of an inverter type crane. It is a block diagram which shows the structure of the electric hoist using the frequency converter of this invention. The graph which shows the variation | change_quantity of the regenerative current value in this invention. It is a flowchart of regeneration resistance protection in the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rectifier, 2 ... Switch power semiconductor, 3 ... Current detector, 4 ... Large regenerative resistor, 5 ... Fuse, 6 ... Thyristor switch, 7 ... Regenerative circuit part, 8 ... Rectifier capacitor, 9 ... Frequency conversion , 10 ... electric motor, 11 ... regenerative resistor, 12 ... regenerative resistor, 13 ... regenerative resistor, 14 ... regenerative resistor, 15 ... regenerative resistor, 16 ... regenerative resistance failure determination circuit, 17 ... crane saddle device, DESCRIPTION OF SYMBOLS 18 ... Saddle motor, 19 ... Trolley motor, 20 ... Trolley device, 21 ... Winding frequency converter, 22 ... Winding regenerative resistance device, 23 ... Electric hoisting machine, 24 ... Winding motor, 25 ... Trolley frequency conversion device, 26 ... Trolley regenerative resistance device, 27 ... Operation input device, 28 ... Saddle frequency conversion device, 29 ... Saddle regenerative resistance device, 30 ... Crane saddle device, 31 ... Saddle motor, 3 ... mains, 33 ... frequency converter, 34 ... controller, 35 ... braking unit, 36 ... display device.

Claims (2)

An electric hoist for cargo handling, an electric trolley device, a frequency converter for driving the electric motor of the electric saddle device , and
A regenerative resistor constituted by parallel connection of a plurality of resistors, to process the regenerative power generated from the motor is converted into heat energy,
A detector for detecting the regenerative current flowing through the entire regenerative resistor,
Comparison means for comparing the detected regenerative current value with a preset current value;
Determination means for determining disconnection of the resistor in the regenerative resistor according to the comparison result of the comparison means;
Control means for controlling the output frequency of the frequency converter according to the comparison result of the comparison means ;
A regenerative resistance fault judgment system , comprising: means for informing the judgment result of the judgment means to the outside . In the regenerative resistance fault judgment system according to claim 1,
When it is determined in the determination means that all the resistors of the regenerative resistor are disconnected, the control means controls the output frequency of the frequency converter to be a frequency at which no regenerative power is generated. Regenerative resistance failure judgment system .

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