KR20060026638A - Control system of rtgc (rubber tyred gantry crane) based on supercapacitor - Google Patents

Abstract

The present invention is a system for controlling a crane capable of moving a load vertically or horizontally, comprising an engine-generator, a load moving motor unit, and a supercapacitor, wherein the supercapacitor generates energy generated by the motor for moving the load. Can be charged and discharged.

The supercapacitor charges and discharges electric energy generated by kinetic energy generated when the load is lowered downward with respect to the ground in the load moving motor unit, or kinetic energy generated during deceleration, thereby providing the potential energy or kinetic energy. Can be recycled. Thus, by the crane control system according to the present invention, it is possible to reduce power consumption and increase energy efficiency.

Description

RCTB control system using supercapacitor {Control System of RTGC (Rubber Tyred Gantry Crane) Based on Supercapacitor}

Figure 1a is a photograph of a rubber tire gantry crane (Rubber Tyred Gantry Crane, RTGC) is a type of crane to which the control system according to the present invention is applied.

Figure 1b is a picture taken an example of a generator used in RTGC.

2 is a block diagram of a conventional RTGC control system.

3 is a view for explaining the basic operation of the RTGC.

Figure 4 is a block diagram of a first embodiment according to the RTGC control system of the present invention.

5 is a block diagram of a second embodiment according to the RTGC control system of the present invention.

6 is a configuration diagram of a DC / DC converter used in the RTGC control system of the second embodiment.

FIG. 7 illustrates current waveforms of respective currents ia, ib, ic, and io corresponding to the operations of switches Q1 to Q6 in the DC / DC converter of FIG.

8 is a graph showing the amount of power applied to the motor unit for moving goods in the experiment for comparing the operation of the conventional RTGC control system and the control system according to the present invention.

9a and 9b are the results of measuring the voltage, current and frequency of the motor portion or the supercapacitor for the load movement of the conventional RTGC control system and the control system according to the present invention, respectively, in the above experiment.

10 is a graph showing power required when power is supplied by a supercapacitor in the RTGC control system according to the present invention, supply power of an engine-generator, and supply power of a supercapacitor.

The present invention relates to a system for controlling a crane capable of moving a load. More specifically, the crane control system according to the present invention includes an engine-generator, a load moving motor unit, a DC / DC converter, and a supercapacitor, wherein the supercapacitor may charge and discharge energy generated in the load moving motor unit. Can be.

The control system according to the present invention is applicable to a crane capable of moving a load, for example, RTGC. RTGC is an abbreviation of Rubber Tyred Gantry Crane, and is a kind of crane for moving cargo such as a container unloaded from a ship to a yard. 1A is a photograph of a conventional RTGC.

The RTGC is itself provided with a generator for driving the RTGC and lifting loads. Figure 1b is an example of the generator used in the RTGC.

2 is a block diagram of a conventional RTGC control system. As shown in FIG. 2, the RTGC control system includes an engine-generator 100 for generating power; A load moving motor unit 200 for moving the load using the power of the engine-generator 100; And the breaker 300 for exhausting a position or kinetic energy generated in the load moving motor unit 200 and connected to the engine-generator 100 in an electrically parallel form with respect to the load moving motor unit 200. It is provided.

The load moving motor unit 200 performs a gantry operation for moving (driving) the RTGC itself back and forth, a hoist operation for vertically moving the load, and a trolley operation for horizontally moving the load. . Figure 3 shows the direction of the gantry operation, hoist operation and trolley operation of the RTGC. Thus, the RTGC can move the article as desired in the x, y and z directions.

In addition, the RTGC control system further includes an auxiliary load driver 400 for driving auxiliary devices such as an air conditioner, a fan, or a pump. The auxiliary load driver 400 is directly connected to the three-phase AC winding of the engine generator 100, and is driven by the power of the engine generator 100.

The distal end of the engine-generator 100 includes a rectifier 110 for converting its output into direct current. The load moving motor unit 200 and the breaker 300 are electrically connected in parallel between the DC links 1 and 2 of the rectifier 110. The inverter 210 for converting the DC power of the DC link (1, 2) to an AC power supply to the motor at the front end of the load moving motor unit 300 is provided.

In the conventional RTGC as described above, the kinetic energy generated when the load is lowered in the load moving motor unit 200 or deceleration is depleted by the breaker 300. Therefore, the energy generated when laying down the load or decelerating is wasted as heat energy in the breaker.

The present invention has been made to solve the above problems, and relates to a crane control system having a supercapacitor for recycling energy generated when a crane such as RTGC puts down a load or decelerates. When using the crane control system according to the invention, it is possible to reduce power consumption and increase energy efficiency.

It is therefore an object of the present invention to provide a new crane power control system.

The present invention relates to a system for controlling a crane (eg RTGC) capable of moving a load. More specifically, the present invention,

An engine-generator for generating electric power;

A load moving motor unit for moving the load using the power of the engine-generator; And

And a large capacity supercapacitor connected to the engine-generator in an electrically parallel form with respect to the load moving motor part and capable of charging and discharging energy generated in the load moving motor part.

Hereinafter, with reference to the drawings will be described in detail with respect to the RTGC control system as an example of a crane according to the present invention. However, the present invention is not limited by the following examples.

4 is a configuration diagram of a first embodiment according to the RTGC control system of the present invention.

RTGC control system according to the first embodiment, the engine-generator 100 for generating electric power; A load moving motor unit 200 for moving the load using the power of the engine-generator 100; And a large capacity supercapacitor connected to the engine-generator 100 in an electrically parallel form with respect to the load moving motor unit 200, and capable of charging and discharging energy generated by the load moving motor unit 200. 500.

The distal end of the engine-generator 100 includes a rectifier 110 for converting its output into direct current. The load moving motor unit 200 and the supercapacitor 500 are electrically connected in parallel between the DC links 1 and 2 of the rectifier 110.

As shown in FIG. 3, the load moving motor unit 200 performs a gantry operation, a hoist operation, and a trolley operation.

The supercapacitor 500 is a motion generated when the load moving motor unit 200 reduces the potential energy generated when the load is lowered with respect to the ground by the hoist operation, or when the RTGC itself or the cargo is decelerated. A large capacity capacitor capable of charging and discharging electrical energy generated by energy. The energy charged in the supercapacitor may drive the load moving motor unit by discharging the energy charged in the supercapacitor when the load moving motor unit performs a gantry operation, a hoist operation, and a trolley operation to move the load. Can be.

As such, in the RTGC control system according to the present invention, since the position and kinetic energy are recycled by the supercapacitor 500, a smaller size engine-generator 100 may be used. That is, since the electrical energy generated by the potential energy or the kinetic energy is recycled, the power consumption of the engine-generator 100 can be reduced, so that a small engine-generator (1 / of the conventional size) can be reduced. 2 or less) can be used. Therefore, miniaturization of the engine and the generator can reduce the no-load loss of the engine and the generator. In the case of RTGC, in particular, no-load operation reaches 50% of the total operation time, which can significantly improve fuel economy by reducing no-load loss. In addition, since the size of the engine is reduced incidentally, pollution problems such as soot and noise can be greatly improved.

In the RTGC control system according to the present invention, it is preferable to use a large capacity supercapacitor having a capacity of several tens F or more and a maximum allowable voltage of about several hundred V or more. In this example, supercapacitors of 30F and 500V capacities were used.

A DC / DC converter 510 may be provided between the supercapacitor 500 and the DC links 1 and 2 to convert a voltage of the supercapacitor, which changes according to energy charging and discharging, into a DC link voltage.

5 is a configuration diagram of a second embodiment according to the RTGC control system of the present invention. For convenience of description, the same reference numerals are given to the same elements as in the first embodiment of the present invention, and detailed descriptions thereof are omitted.

In the RTGC control system according to the second embodiment, an auxiliary load driver 400 for driving an auxiliary device of an RTGC, such as an air conditioner, a fan, or a pump, may include a DC link (1, 1) of the rectifier (110). It is connected to 2). Accordingly, the auxiliary load driver 400, the load moving motor 200, and the supercapacitor 500 are connected to the DC links 1 and 2 in an electrically parallel form.

As described above, the energy charged in the supercapacitor is charged in the supercapacitor for the operation of the auxiliary load driver 400 as well as the gantry operation, the hoist operation and the trolley operation of the load moving motor unit 200. The charged energy may be discharged to use the charged energy.

An inverter 410 is required between the auxiliary load driving unit and the DC links 1 and 2 to convert a DC power source into a three-phase AC power source having a constant voltage and a constant frequency.

6 is a detailed configuration diagram of the DC / DC converter 510 between the supercapacitor 500 and the DC links 1 and 2. The DC / DC converter 510 includes a plurality of switches Q1 to Q6 connecting the DC link and the supercapacitor. By periodically opening and closing the switches Q1 to Q6, the energy of the supercapacitor may be efficiently controlled.

At this time, the switches (Q1 ~ Q6) is preferably opened and closed with a time difference of each other. In particular, when the switches Q1 to Q6 are opened and closed at intervals of 1/3 time with respect to the entire switch opening / closing period, the pulsating current of the supercapacitor can be minimized. FIG. 7 shows waveforms of currents i _a , i _b , i _c and the sum of i ₀ current (supercapacitor current) according to the operations of the switches Q1 to Q6.

Hereinafter, a simulation example (simulation) for confirming the operation of the RTGC control system according to the present invention will be described.

First, in order to drive the conventional RTGC as shown in FIG. 2 and the RTGC of the present invention as shown in FIG. 4, electric power as shown in FIG. 8 was applied to the load moving motor part. At this time, the voltage, current, and frequency in the load moving motor unit or the supercapacitor were measured. 9 is a power waveform during a hoist operation for lifting a load, and it is assumed that power of 0 to 5 seconds is power for driving an auxiliary device, and its magnitude is constant for the entire operation time. In FIG. 9, the 5 seconds to 6.5 seconds section is an acceleration section, the 6.5 seconds to 15 seconds section is a constant speed driving section, and the 15 seconds to 16.5 seconds section is a deceleration section.

The main constants of the engine-generator of the conventional RTGC control system and the RTGC control system according to the present invention used in this Experimental Example are shown in Table 1 below:

[Table 1] Main Constants of Engine-Generators

Conventional RTGC RTGC of the present invention 375kW 122kW Diesel engine Rated power 400 kW 132kW Rated speed 1800r / min 1800r / min Dimensions (L × Ｗ × H, mm) 1379 × 889 × 1295 1182 × 710 × 1137 weight 3410 kg 1498 kg Rated power 375kW 122kW Voltage / current 460V / 588A 220-480V Frequency / PF 60 Hz / 0.8 60 Hz / 0.8 to 1 Top / pole 3/4 3/4

Experimental results in the conventional RTGC is shown in Figure 9a, and experimental results in the RTGC according to the present invention is shown in Figure 9b.

As shown in FIG. 9B, when the RTGC is controlled according to the present invention, it can be seen that the fluctuation of the frequency and the voltage fluctuation in the DC link are very small. Therefore, it can be seen that the electric power is stably supplied to the load moving motor unit. In addition, it can be seen that during the hoist operation of lifting the load, energy charged in the supercapacitor is discharged, and energy is supplied to the load moving motor unit.

FIG. 10 shows power required when electric power is supplementally supplied by a supercapacitor in a situation where a constant power (120 kW) is supplied from an engine generator in the RTGC control system according to the present invention, a power supply of the engine generator, and The power supply of the supercapacitor is shown graphically. In the engine-generator, 120kW of power is supplied, and the electric energy charged in the supercapacitor is discharged during the hoist operation, which requires a lot of power, and thus power is supplied to the motor for moving goods.

Therefore, even when an engine-generator having a relatively low output is used, the RTGC can be normally controlled.

As described above, in the RTGC control system according to the present invention, the supercapacitor is generated by the potential energy generated when the load is lowered downward with respect to the ground in the load moving motor, or by the kinetic energy generated during deceleration. After charging the energy, the energy can be recycled by discharging it when accelerating or raising the load. Thus, by the crane control system according to the present invention, it is possible to reduce power consumption and increase energy efficiency.

In particular, since a relatively small engine-generator of 120 kW class can be used as an engine-generator instead of 350 kW class, no-load loss can be reduced to significantly improve fuel efficiency. In addition, because of the small size and capacity of the engine-generator, fuel consumption is low, and noise generation and emission of environmental pollutants are reduced. In addition, it is possible to stably maintain the voltage between the frequency and the DC link to reduce the inverter capacity of the motor drive system.

Claims (8)

A system for controlling a crane that can move cargo, An engine-generator for generating electric power; A rectifier provided at an end of an output unit for outputting power of the engine generator and converting the power of the engine generator into direct current; A load moving motor unit electrically connected between the DC link which is the output of the rectifier and moving the load using the power of the engine-generator; A supercapacitor connected to the DC link in an electrically parallel form with respect to the load moving motor unit and capable of charging and discharging energy generated by the load moving motor unit; And And a DC / DC converter interposed between the supercapacitor and the DC link and capable of converting the magnitude of the DC voltage. 2. The crane control system according to claim 1, wherein an inverter capable of converting DC power into three-phase AC power is provided between the load moving motor unit and the DC link. According to claim 1, wherein the supercapacitor is electric energy generated by the potential energy generated when the load is lowered downwards with respect to the ground in the load moving motor unit, or the kinetic energy generated when the crane itself or the deceleration of the load Crane control system, characterized in that to charge and discharge. The crane control system according to claim 1, further comprising an auxiliary load driving unit for driving an auxiliary device of the crane. 5. The crane control system according to claim 4, wherein the auxiliary load driving unit is connected to the DC link of the rectifier in an electrically parallel form with respect to the load moving motor unit and the supercapacitor. The crane control system according to any one of claims 1, 4, and 5, wherein the motor for moving goods is driven by discharge of electric energy charged in the supercapacitor. 7. The crane control system according to claim 6, wherein the auxiliary load driving unit is driven by discharge of electric energy charged in the supercapacitor. According to claim 1, The DC / DC converter is provided with three-phase switches for connecting the DC link and the supercapacitor, Each phase switch is a crane control system, characterized in that the opening and closing each 1/3 time interval of the switch opening and closing intervals.

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