KR20180060076A - Rtgc controlling system and the controlling method thereof - Google Patents

Abstract

The present invention relates to an RTGC control system and method in which a battery is charged by electric energy converted from potential or kinetic energy generated when a cargo is unloaded on the ground, and is discharged when the cargo is loaded. The RTGC control system includes a generator for generating electricity; a rectifier provided on a terminal end of an output unit of the generator to convert the electricity to a DC current; a motor electrically connected to a DC link which is an output of the rectifier, to transfer a cargo by the electricity of the generator; a battery electrically connected to the DC link in parallel with the motor to charge or discharge the energy generated from the motor; a DC/DC converter provided between the battery and the DC link to convert intensity of DC voltage; an inverter provided between the motor and the DC link to convert the DC power to AC power; and a controller for controlling charging or discharging of the battery according to DC-bus voltage measured by the DC link.

Description

TECHNICAL FIELD [0001] The present invention relates to an RTGC control system and a control method thereof,

More particularly, the present invention relates to an RTGC control system and a control method thereof. More particularly, the present invention relates to a RTGC control system and a control method thereof, and more particularly, And to control the charging or discharging of the battery based on the DC-BUS voltage.

RTGC is an abbreviation of Rubber Tyred Gantry Crane. It is a kind of crane for moving cargo such as a container unloaded from a ship to a yard.

The RTGC has its own RTGC and a generator to lift the cargo.

FIG. 1 is a block diagram of a conventional RTGC control system, and FIG. 2 is a diagram for explaining a DC-BUS voltage and a motor input voltage according to the motion of a conventional RTGC.

1, the RTGC control system 100 includes a generator 110 for generating electric power, a motor 130 for moving a cargo using electric power of the generator 110, And a DBU (Dynamic Braking Unit) 160 connected to the generator 110 for exhausting a position or kinetic energy generated by the motor 130.

The motor 130 performs a gantry operation for moving the RTGC itself back and forth, a hoist operation for vertically moving the cargo, and a trolley operation for horizontally moving the cargo. The RTGC can move the cargo in x, y and z directions as desired.

At the distal end of the generator 110, a rectifier 120 for converting its output to direct current is included. The motor 130 and the DBU 160 are electrically connected in parallel between the DC links 1 and 2 of the rectifier 120. An inverter 140 is provided at the front end of the motor 130 to convert the DC power of the DC link 1, 2 into AC power and supply the AC power to the motor.

The RTGC control system supplies the electric power of the motor 130 driving the crane in the generator 110. As shown in FIG. 2, the motion of the crane to lift the cargo during the up-down operation is consumed by power consumption. When the cargo is lowered, the motor 130 performs the power generation operation. The developed electric power operates the DBU 160 while raising the voltage of the DC-BUS to burn it as a resistor. As shown in FIG. 2, the electric power equivalent to the yellow area is burned as a resistor.

In the conventional RTGC control system, the kinetic energy generated when the cargo is lowered downward from the motor or generated during deceleration is exhausted by the DBU 300. Therefore, the energy generated when the cargo is lowered or decelerated is wasted as thermal energy in the DBU.

Prior Art 1: Korea Patent Publication No. 2010-0011039: Power Control Device of Crane with Engine Generator

It is an object of the present invention to provide an RTGC control system and a control method thereof, in which a crane such as RTGC is equipped with a battery for reusing energy generated when a cargo is lifted or decelerated.

It is another object of the present invention to provide an RTGC control system and a control method thereof for controlling charging or discharging of a battery based on a DC-BUS voltage so that the SOC of the battery maintains a target SOC.

According to an aspect of the present invention, there is provided an electric power generator comprising: a generator for generating electric power; a rectifier provided at an end of an output unit for outputting electric power of the generator, A motor that is electrically connected between the DC link and electrically connected to the DC link with respect to the motor, and that charges and discharges energy generated by the motor, A DC / DC converter provided between the battery and the DC link for converting the magnitude of the DC voltage, an inverter provided between the motor and the DC link for converting the DC power into the AC power, And a controller for controlling charging or discharging of the battery according to a DC-BUS voltage measured in the RTGC control The system is provided.

The control unit controls charging or discharging of the battery based on the DC-BUS voltage and the SOC of the battery so that the SOC of the battery maintains the target SOC. When the current SOC is not equal to the target SOC, The target SOC can be reset.

If the current SOC is not equal to the target SOC, the controller obtains a value obtained by subtracting the current SOC from the target SOC with a target error, and when the obtained target error exceeds '0' Reset the product to the target SOC, and maintain the target SOC if the target error does not exceed zero.

When the DC-BUS voltage is equal to or higher than the charge start set voltage and equal to or less than the discharge start set voltage and the SOC of the battery is equal to or higher than the charge completion SOC setting value and is not lower than the discharge complete SOC setting value, the controller operates in the discharge operation mode , The battery is discharged, and when the DC-BUS voltage is equal to or higher than the charge start set voltage and the SOC of the battery is not equal to or higher than the charge completion SOC set value, the battery can be charged and operated in the charge operation mode.

According to another aspect of the present invention, there is provided a method of controlling a battery, comprising the steps of: (a) controlling charging or discharging of the battery based on a DC-BUS voltage and an SOC of the battery and measuring a current SOC; (b) And (c) if the current SOC is not the same as the target SOC, resetting the target SOC and performing the step (b).

If the DC-BUS voltage is equal to or higher than the charge start set voltage and equal to or less than the discharge start set voltage and the SOC of the battery is equal to or higher than the charge completion SOC setting value and equal to or less than the discharge complete SOC setting value, Discharging the battery and measuring a discharge current value, and measuring the current SOC when the measured discharge current value is equal to or less than a minimum charge current value.

Wherein the step (a) comprises the steps of charging the battery by operating in a charge operation mode when the DC-BUS voltage is equal to or higher than the charge start set voltage and the SOC of the battery is not greater than the charge completion SOC setting value, And measuring the current SOC.

In the step (a), the current SOC of the battery can be measured when the DC-BUS voltage is not equal to or less than the charge start set voltage but less than the discharge start set voltage.

In the step (a), if the DC-BUS voltage is not equal to or less than the charge start set voltage but less than the discharge start set voltage and the SOC of the battery is less than or equal to the discharge completion SOC set value, .

Wherein the step (c) includes: obtaining a value obtained by subtracting the current SOC from the target SOC, with a target error when the current SOC is not equal to the target SOC; Value to a target SOC, and maintaining the target SOC when the target error does not exceed '0'.

According to the present invention, in a RTGC control system, a battery charges electric energy generated by kinetic energy generated when a cargo is lowered downward relative to a ground, Or discharging it when it is lifted, it can recycle energy, thereby reducing power consumption and increasing energy efficiency.

In addition, during operation between the voltage of the DBU and the DC-BUS minimum voltage section, surplus power is absorbed so that the DBU does not operate, and the operation loss is minimized while the battery is discharged in a section requiring power.

Further, by controlling the charging or discharging of the battery based on the DC-BUS voltage, the SOC of the battery can be maintained at the target SOC.

1 is a block diagram of a conventional RTGC control system.
2 is a view for explaining a DC-BUS voltage and a motor input voltage according to the movement of a conventional RTGC.
3 illustrates an RTGC control system in accordance with an embodiment of the present invention.
4 is a flowchart illustrating an RTGC control method according to an embodiment of the present invention.
5 is a view for explaining a battery control area applied to an RTGC according to an embodiment of the present invention.

Hereinafter, the RTGC control system and its control method according to the present invention will be described in detail with reference to the accompanying drawings. The embodiments are provided so that those skilled in the art can easily understand the technical spirit of the present invention, and thus the present invention is not limited thereto. In addition, the matters described in the attached drawings may be different from those actually implemented by the schematic drawings to easily describe the embodiments of the present invention.

In the meantime, each constituent unit described below is only an example for implementing the present invention. Thus, in other implementations of the present invention, other components may be used without departing from the spirit and scope of the present invention. In addition, each component may be implemented solely by hardware or software configuration, but may be implemented by a combination of various hardware and software configurations performing the same function. Also, two or more components may be implemented together by one hardware or software.

Also, the expression " comprising " is intended to merely denote that such elements are present as an expression of " open ", and should not be understood to exclude additional elements.

3 is a diagram illustrating an RTGC control system according to an embodiment of the present invention.

3, the RTGC control system 300 includes a generator 310 for generating electric power, a rectifier 320 for converting the power of the generator 310 into a DC power, a DC link 1, which is an output of the rectifier 320, 2 and connected to the DC link 1 and 2 electrically in parallel with the motor 330 for moving the cargo using the electric power of the generator 310, A battery 370 for charging and discharging the energy generated by the motor 330, a DC / DC converter 380 provided between the battery 370 and the DC links 1,2 to convert the magnitude of the DC voltage, An inverter 340 which is provided between the DC link 330 and the DC link 1 and converts the DC power into an AC power; And a control unit 390 for controlling the discharge.

The RTGC control system 300 is connected to the generator 310 electrically in parallel with the motor 330 and includes a Dynamic Brake Unit (DBU) 360 for exhausting the position or kinetic energy generated by the motor 330, .

The distal end of the generator 310 includes a rectifier 320 for converting its output to direct current. The motor 330, the DBU 360 and the battery 370 are electrically connected in parallel between the DC link 1, 2 of the rectifier 320.

The motor 330 performs a gantry operation to move the RTGC back and forth, a hoist operation to move the cargo vertically, and a trolley operation to move the cargo horizontally. The RTGC can move the cargo in x, y and z directions as desired.

The battery 370 is an electric motor generated by the motor 330 by the kinetic energy generated when the RTGC itself or the cargo is decelerated by the potential energy generated when the cargo is lowered downward relative to the ground by the hoist operation, Energy can be charged and discharged. The energy stored in the battery 370 can be used to drive the motor 330 by discharging the energy stored in the battery 370 when the motor performs a gantry operation, a hoist operation, a trolley operation, have.

In this way, since the RTGC control system 300 according to the present invention recycles the position and kinetic energy by the battery 370, it is possible to use the lesser sized generator 310. That is, since the electric energy generated by the position energy or the kinetic energy is recycled, the power consumption of the generator 310 can be reduced, and a smaller size of the engine-generator ) Can be used. Therefore, it is possible to reduce the no-load loss of the engine and the generator through miniaturization of the engine and the generator. In particular, in the case of RTGC, since no-load operation reaches 50% of the total operation time, the fuel consumption can be greatly improved by reducing the no-load loss. In addition, since the size of the engine is reduced incidentally, pollution problems such as smoke and noise can be significantly improved.

A DC / DC converter 380 is provided between the battery 370 and the DC links 1 and 2 to convert the voltage of the battery 370, which changes in accordance with the energy charge and discharge, into a DC link voltage.

The generator 310 supplies power to the motor 330 that drives the crane. The movement of lifting the cargo during the up and down operation of the crane is consumed by power consumption. When the cargo is lowered, the motor 330 performs the power generation operation. The developed electric power is supplied to the battery 370 when the motor 330 is driven. In this operation, the operation of managing the SOC of the battery 370 is essential, and the control unit 390 performs the operation of managing the SOC of the battery 370. [

The control unit 390 controls the charging or discharging of the battery based on the DC-BUS voltage and the SOC of the battery 370 so that the SOC of the battery 370 maintains the target SOC, If not, the target SOC is reset. Here, the current SOC means the current SOC value of the battery 370, and the target SOC means the final target SOC value. That is, when the current SOC is not equal to the target SOC, the controller 390 obtains a target SOC minus the current SOC as the target error, and when the obtained target error exceeds '0', the charge current setting value and the target error Is reset to the target SOC, and the target SOC is maintained when the target error does not exceed '0'.

The controller 390 controls charging or discharging of the battery 370 based on the DC-BUS voltage and the SOC of the battery 370. That is, when the DC-BUS voltage is equal to or higher than the charge start set voltage and equal to or less than the discharge start set voltage, and the SOC of the battery 370 is equal to or greater than the charge completion SOC set value and equal to or less than the discharge complete SOC set value, Operates in the operation mode, and discharges the battery 370. If the DC-BUS voltage is equal to or higher than the charge start setting voltage and the SOC of the battery 370 is not equal to or higher than the charge completion SOC setting value, the controller 390 operates in the charge operation mode to charge the battery 370 .

The RTGC control system 300 configured as described above performs charging and discharging of the battery 370 according to the voltage level of the DC-Bus 350. The DBU 360 absorbs surplus power so that the DBU 360 does not operate while the DBU 360 operates and the DC-BUS minimum voltage interval, do. And the target SOC is maintained in the non-driving section.

FIG. 4 is a flowchart illustrating an RTGC control method according to an embodiment of the present invention, and FIG. 5 is a view for explaining a battery control region applied to the RTGC according to an embodiment of the present invention.

Referring to FIG. 4, the RTGC control system measures the DC-BUS voltage and determines whether the DC-BUS voltage is equal to or higher than a charge start voltage (S302). The charge start set voltage may be a preset voltage value.

If it is determined in step S302 that the charging start setting voltage is not equal to or higher than the charging start setting voltage, the RTGC control system determines whether the SOC is equal to or greater than a predetermined charging SOC setting value (S304).

If it is determined in step S304 that the charge completion SOC is not less than the set value, the RTGC control system determines whether the DC-BUS voltage is equal to or less than the discharge start voltage (S306).

If it is determined in step S306 that the discharge start set voltage is not exceeded, the RTGC control system determines whether the SOC is equal to or less than a predetermined discharge SOC setting value (S308).

If it is determined in step S308 that the discharge completion SOC is not equal to or less than the set value, the RTGC control system operates in the discharge operation mode to discharge the battery power (S320).

Then, the RTGC control system measures the discharge current value discharged from the battery and judges whether or not the measured discharge current value is equal to or less than the minimum charge current value for stopping the charge (min charge current) S322).

As a result of the determination in step S322, if the value is less than the minimum charge current value, the RTGC control system determines whether the current SOC is equal to the target SOC (S312).

If it is determined in step S312 that the current SOC is not equal to the target SOC, the RTGC control system determines whether the target error exceeds '0' (S314). Here, the target error may be a value obtained by subtracting the current SOC from the target SOC.

If it is determined in step S314 that the target error exceeds '0', the RTGC control system multiplies the charge current setting value by the target error and resets the multiplied value to the target SOC (S316).

The RTGC control system then performs step S312.

If it is determined in step S314 that the target error does not exceed '0', the RTGC control system maintains the target SOC (S318) and performs step S312.

If it is determined in step S304 that the SOC is not equal to or greater than the charge completion SOC setting value, the RTGC control system operates in the charge operation mode to charge the battery (S310) and performs step S312.

If it is determined in step S302 that the DC-BUS voltage is not equal to or higher than the charge start set voltage, the RTGC control system performs step S306.

If it is determined in step S306 that the DC-BUS voltage is not equal to or less than the discharge start set voltage, the RTGC control system performs step S312.

As described above, the RTGC control system basically maintains the target SOC, and when the motor is operated during the operation in the charge mode, the DC-BUS voltage will drop. At this time, the discharge mode is changed to control the DC-BUS voltage. When the discharge amount decreases during discharging, the charging mode is changed again. While operating in the charge mode, the remaining power is charged while controlling the SOC. When the algorithm shown in FIG. 4 is applied, the battery operates in the hatched area as shown in FIG. 5, and maintains the DC-BUS voltage. While maintaining the DC-BUS voltage, the battery is judged to be fluid, absorbing surplus power and compensating for insufficient power.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

310: Generator 320: Rectifier
330: motor 340: inverter
350: DC BUS 360: DBU
370: Battery 380: DC / DC converter
390:

Claims (10)

A generator for generating electric power;
A rectifier provided at an end of an output unit for outputting power of the generator and converting the power of the generator into a direct current;
A motor electrically connected between the DC link as an output of the rectifier and moving the cargo using electric power of the generator;
A battery connected to the DC link in an electrically parallel manner to the motor and charging and discharging energy generated in the motor;
A DC / DC converter provided between the battery and the DC link for converting the magnitude of the DC voltage;
An inverter provided between the motor and the DC link for converting DC power into AC power; And
A control unit for controlling charging or discharging of the battery according to a DC-BUS voltage measured at the DC link;
Gt; RTGC < / RTI > The method according to claim 1,
The control unit controls charging or discharging of the battery based on the DC-BUS voltage and the SOC of the battery so that the SOC of the battery maintains the target SOC. When the current SOC is not equal to the target SOC, And resets the target SOC. 3. The method of claim 2,
If the current SOC is not equal to the target SOC, the controller obtains a value obtained by subtracting the current SOC from the target SOC with a target error, and when the obtained target error exceeds '0', the charge current set value and the target error Resets the product to the target SOC, and maintains the target SOC if the target error does not exceed '0'. The method according to claim 1,
When the DC-BUS voltage is equal to or higher than the charge start set voltage and equal to or less than the discharge start set voltage and the SOC of the battery is equal to or higher than the charge completion SOC setting value and is not lower than the discharge complete SOC setting value, the controller operates in the discharge operation mode , The battery is discharged, and when the DC-BUS voltage is equal to or higher than the charge start set voltage and the SOC of the battery is not equal to or higher than the charge completion SOC setting value, the battery is charged in the charge operation mode. Control system. (a) controlling the charging or discharging of the battery based on the DC-BUS voltage and the SOC of the battery and measuring the current SOC;
(b) determining whether the measured current SOC is equal to a target SOC; And
(c) if the current SOC is not the same as the target SOC, resetting the target SOC and performing the step (b);
Gt; RTGC < / RTI > 6. The method of claim 5,
The step (a)
When the DC-BUS voltage is equal to or higher than the charge start set voltage and equal to or less than the discharge start set voltage and the SOC of the battery is equal to or higher than the charge completion SOC setting value and is not lower than the discharge complete SOC setting value, And measuring a discharge current value; And
And measuring the current SOC when the measured discharge current value is less than the minimum charge current value. 6. The method of claim 5,
The step (a)
Charging the battery by operating in a charge operation mode when the DC-BUS voltage is equal to or higher than the charge start set voltage and the SOC of the battery is not equal to or higher than the charge completion SOC setting value;
And measuring the current SOC of the battery. 6. The method of claim 5,
The step (a)
Wherein the current SOC of the battery is measured when the DC-BUS voltage is not equal to or less than the charge start set voltage but less than the discharge start set voltage. 6. The method of claim 5,
The step (a)
Wherein the current SOC of the battery is measured when the DC-BUS voltage is equal to or lower than the discharge start set-up voltage and not equal to or higher than the charge start set voltage, and the SOC of the battery is less than or equal to the discharge completion SOC set value. . 6. The method of claim 5,
The step (c)
Obtaining a value obtained by subtracting the current SOC from the target SOC as a target error if the current SOC is not the same as the target SOC;
Resetting the product of the charge current set value and the target error to the target SOC when the obtained target error exceeds 0 and maintaining the target SOC when the target error does not exceed 0 Characterized by an RTGC control method.

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