JP3960555B1 - Control method of harbor handling crane system - Google Patents

Abstract

Provided is a control method for a harbor cargo handling crane system in which energy stored in a capacitor power storage circuit is positively used to improve energy use efficiency of the entire crane system .
A control method for a harbor cargo handling crane system according to the present invention includes a generator 11 having at least a diesel engine 10 as a power source, a rectifier circuit 12 for converting electric power generated from the generator 11 into direct current, and a rectifier circuit. 12, an inverter circuit 16 that converts DC power generated from the AC power into AC power, a capacitor storage circuit 14 that stores DC power between the rectifier circuit 12 and the inverter circuit 16, and an electric motor driven by the output from the inverter circuit 16. 17 and a crane 18 powered by the electric motor 17, the diesel engine 10 is always turned on, the electric power is always generated by the generator 11, and the electric power stored in the capacitor power storage circuit 14 is supplementarily used. The mode and the diesel engine 10 are appropriately turned on, and power is generated by the generator 11 as necessary. It is generated, and an unloading mode is used primarily power stored in the capacitor storage circuit 14.
[Selection] Figure 1

Description

The present invention relates to a control method for a harbor cargo handling crane system for loading containers on a ship or trailer in a yard such as a harbor .

In a yard such as a harbor, transport operations such as loading of a container on a ship or trailer and unloading of a container from the ship or trailer are performed by a crane device. When these containers are loaded and unloaded, the containers are wound and unwound by a motor provided in the crane apparatus.

In recent years, improvement in the handling efficiency of the yard has been demanded, and various techniques for improving the handling efficiency have been proposed. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-131411) discloses a converter device that converts AC power supplied from an AC power source into DC power, an inverter device that converts DC power into desired AC power, and a crane. An AC motor for driving the main operating mechanism, and an AC motor drive operation switch that is closed when the motor is driven, AC power from the AC power source is also supplied to an auxiliary load, and the converter device and the inverter device are In a port control crane control device with a regenerative function capable of returning power generated on the secondary side to the primary side, connected to the secondary side of the converter device, and converts natural energy into electrical energy to convert the converter device A DC generator for flowing through the DC circuit on the secondary side, and a diode for preventing a backflow of DC generated power obtained by the DC generator. And a DC power generator changeover switch for switching between cargo handling work and power generation using natural energy, and a storage battery connected to the secondary side of the converter device for storing DC power generated by natural energy. A crane control device for harbor cargo handling is disclosed.

As another proposed example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-362710) discloses a traveling vehicle that travels by receiving power from a power supply line. A traveling cart is disclosed, in which a motor is operated as a brake by the control unit by driving a motor control unit of the traveling cart with electric power to decelerate and stop the traveling cart.
JP 2006-131311 A JP 2002-362710 A

  Each of the devices described in Patent Document 1 and Patent Document 2 has a power storage unit such as a capacitor, but these power storage units are configured to pool excess regenerative power and natural energy. , Do not actively use this.

In order to solve such a problem, the present invention relates to a generator having at least an engine as a power source, a rectifier circuit for converting electric power generated from the generator into direct current, An inverter circuit that converts DC power generated from the rectifier circuit into AC power; a capacitor storage circuit that stores DC power between the rectifier circuit and the inverter circuit; and an electric motor driven by an output from the inverter circuit; A crane powered by the electric motor, a voltage detection circuit for detecting a voltage applied to the capacitor storage circuit, a current detection circuit for detecting a current flowing through the capacitor storage circuit, the voltage detection circuit, and the current detection circuit of the detection signal and the system control circuit is input, in the cargo handling crane system equipped with a mode frying load in altitude from a low place, the engine Always generates power by always the generator as on the unloading mode using power stored in the capacitor storage circuit as an auxiliary, is a mode of reducing the load at low from a height, as appropriate on the engine An unloading mode in which electric power is generated by the generator as needed and the electric power stored in the capacitor storage circuit is mainly used, and the system control circuit includes the voltage detection circuit and the current detection circuit. Based on the detection signal of the capacitor storage circuit, when the electric power tends to be stored in the capacitor storage circuit, it is determined as the unloading mode, and when the electric power of the capacitor storage circuit tends to be consumed, the unloading mode is determined. It is characterized by determining .

The invention according to claim 2 is characterized in that, in the method for controlling a harbor cargo handling crane system according to claim 1, regenerative power generated by the motor when the crane is lowered is stored in the capacitor storage circuit. .

The invention according to claim 3 is characterized in that, in the method for controlling a harbor cargo handling crane system according to claim 1 or 2, regenerative power generated by the electric motor is consumed by a resistor when the crane is lowered. .

  According to the harbor cargo handling crane system according to the embodiment of the present invention, since it is configured to detect the storage tendency of the capacitor storage circuit and use this as a guide to switch between the unloading mode and the unloading mode, the capacitor The electric power stored in the power storage circuit can be actively used, and the energy utilization efficiency of the entire crane system can be increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a circuit configuration of a harbor cargo handling crane system according to an embodiment of the present invention. In FIG. 1, 10 is a diesel engine, 11 is a generator, 12 is a rectifier circuit, 13 is a charge control circuit, 14 is a capacitor storage circuit, 15 is a DC-DC conversion circuit, 16 is an inverter circuit, 17 is an electric motor, and 18 is an electric motor. The crane operating part, 20 is a voltage detection circuit, 21 is a current detection circuit, and 22 is a system control circuit.

  The power of the diesel engine 10 using heavy oil as an energy source is transmitted to the generator 11 to generate an alternating current. Rectifier circuit 12 is a rectifier constituted by a three-phase bridge of a diode, and converts a three-phase AC voltage of the AC power source into a DC voltage. The charge control circuit 13 controls charging to the capacitor storage circuit 14, and the DC-DC conversion circuit 15 controls input to the inverter circuit 16. The inverter circuit 16 is an inverter composed of a three-phase bridge of a rectification control element composed of a transistor and a free-wheeling diode. The inverter circuit 16 outputs a DC voltage output from the DC-DC conversion circuit 15 as a variable voltage and variable frequency three-phase AC. It is a PWM inverter that converts voltage. The output from the inverter circuit 16 is input to the electric motor 17, and the torque generated thereby is used by the crane operating unit 18 to unload and unload the container. The voltage detection circuit 20 detects the voltage between the terminals T and T ′, and the current detection circuit 21 detects the current flowing between the T and T ′. The system control circuit 22 receives the detection results from the voltage detection circuit 20 and the current detection circuit 21 and controls the entire harbor handling crane system.

  A specific operation in the harbor cargo handling crane system configured as described above will be described. FIG. 2 is a diagram illustrating the operation of the crane in the harbor handling crane system according to the embodiment of the present invention. In FIG. 2, 31 indicates a ship, 32 indicates a yard, and 33 indicates a load such as a container.

FIG. 2A is a diagram showing a situation where the load 33 is lifted from a low place to a high place, and FIG. 2B is a diagram showing a situation where the load 33 is lowered from a high place to a low place. The operation of the harbor handling crane system such as the former will be referred to as an unloading mode, and the operation of the harbor handling crane system such as the latter will be referred to as an unloading mode.
(A) Unloading mode When the crane unloads, the diesel engine 10 is always turned on. The generator 11 is used as the main power of the crane, and the electric power stored in the capacitor in the capacitor storage circuit 14 is used to assist (peak cut) the lifting of the load (such as a container).

Further, when the crane stops or when the crane turns, the electric power from the generator 11 generated because the diesel engine 10 is always on is rectified and charged to the capacitor storage circuit 14 as a constant current source. Note that the regenerative power generated by the electric motor 17 by the potential energy when the load is lowered (when the crane is lowered) may be stored in the capacitor storage circuit 14 as appropriate.
(B) When the crane performs unloading in the unloading mode, the capacitor power storage circuit 14 is used as the main power, and the load is lifted (crane lift) using the power stored in the capacitor power storage circuit 14 in advance. Also, the regenerative electric power generated by the potential energy of lifting (crane descending) is stored in the capacitor storage circuit 14, and only when the stored amount of energy is not less than a certain level (despite storing the potential energy), the diesel engine 10 Is turned on, the generator 11 is operated and charged.

  On the other hand, if the regenerative power exceeds the storage capacity of the capacitor storage circuit 14 by repeating unloading (crane descending) (that is, the stored power by unloading the load is consumed by lifting the load or turning the crane). Since the amount of electricity stored will increase if it cannot be used), it is recommended to use a resistor (not shown) separately installed to cause power generation control to be consumed.

  Next, in the harbor handling crane system according to the embodiment of the present invention, the determination of the unloading mode and the unloading mode will be described. The voltage detection circuit 20 detects a voltage between the terminals T and T ′ and transmits a detection signal related to the voltage to the system control circuit 22. Further, a current flowing between the current detection circuit 21 and the terminal T-T ′ is detected, and a detection signal related to this is transmitted to the system control circuit 22. The system control circuit 22 has arithmetic means such as a microcomputer (not shown), and calculates the product of the voltage value obtained from these voltage detection signals and the current value obtained from the current detection signals. Thereby, the system control circuit 22 determines whether power tends to be accumulated in the capacitor power storage circuit 14 or a power tends to be consumed in the capacitor power storage circuit 14 by a series of operations of the crane, It is determined whether the crane system is to be in an unloading mode or an unloading mode. The system control circuit 22 determines the unloading mode when power tends to be stored in the capacitor power storage circuit 14, and sets the unloading mode when power tends to be consumed by the capacitor power storage circuit 14. judge. Based on the determination as described above, the system control circuit 22 always turns on the diesel engine 10 (that is, whether the generator 11 always generates power) or appropriately turns on the diesel engine 10 ( That is, an on / off signal relating to whether or not electric power is generated by the generator 11 as required is output to the diesel engine 10.

  The unloading mode and the unloading mode in the crane system may be configured to be manually switched as appropriate without depending on the determination as described above.

  As described above, the harbor handling crane system according to the embodiment of the present invention is configured to detect the power storage tendency to the capacitor power storage circuit 14 and switch between the unloading mode and the unloading mode using this as a guide. Therefore, the electric power stored in the capacitor storage circuit 14 can be actively used, and the energy utilization efficiency of the entire crane system can be improved.

  Hereinafter, specific examples will be quantified and described. In this example, the crane load is 50 tons. The electric motor 17 that drives this is 150 kW, the capacitor in the capacitor storage circuit 14 has a voltage of DC 600 V, a capacitance of 84 F, and a storage amount of 4.2 kWh. The capacity of the generator 11 is 200 kW. If this storage capacity is sufficient, the load can be lifted to a height of 15 m with only the electric power stored in the capacitor by a 50-ton load, and the baggage can be lowered to a predetermined position. When descending, the motor 17 acts as a generator to charge the capacitor in the capacitor storage circuit 14.

  This is illustrated in FIG. The capacitor is charged to DC 600V at the start-up, and as the load 33 is lifted, the voltage drops to DC 400V at the maximum height. When the DC-DC conversion circuit 15 supplies constant power to the inverter circuit 16, the current value increases as the capacitor storage voltage decreases, so that the DC-DC conversion circuit 15 is normally used up to about DC300V, which is a half voltage.

  When the load 33 is lowered, the braking energy is charged to the capacitor as regenerative power, and the voltage is finally charged to DC538V. The voltage drop DC62V in this cycle is the power conversion loss (0.82 kWh) in this operation. In this example, since the capacitor capacity of the capacitor storage circuit 14 is sufficiently planned, the power supply by the generator 11 is not performed. However, when the amount of electricity stored in the capacitor in the capacitor electricity storage circuit 14 is reduced by half, power shortage occurs during the ascending operation, so the generator 11 needs to be activated.

  This is shown in FIG. In the operation curve in FIG. 4, at the time of 21.4 seconds, the voltage drop of the capacitor in the capacitor storage circuit 14 decreases to DC 400 V or less, resulting in power shortage. Therefore, the generator 11 is started and 163 kW is supplied with the maximum power. ing. In the crane descent operation, a part of the power of the generator 11 and the regenerative power are charged in the capacitor, and finally the voltage of the capacitor in the capacitor storage circuit 14 is DC624V.

  As shown in FIG. 4, even if the generator 11 is started after the power of the capacitor in the capacitor storage circuit 14 is lowered, the peak power close to the maximum power 200 kW of the generator 11 is required and the effect of reducing the capacity of the generator 11 is Few. Further, when insufficient power is supplied to the load after the capacitor is discharged, the capacitor storage circuit 14 is recharged and the capacity for charging the regenerative power becomes insufficient, so that the capacitor storage circuit 14 becomes higher than the initial voltage and the voltage tolerance of the capacitor storage circuit 14 is increased. There is a factor that increases the equipment cost that must be increased.

  Therefore, as shown in FIG. 5, the generator capacity can be reduced by performing constant current charging from the generator 11 during the period in which power is discharged from the capacitor to the load in the capacitor storage circuit 14. That is, in FIG. 5, the capacitor storage circuit 14 is discharged during the ascending operation, and when the capacitor voltage reaches the highest level by charging the capacitor of the capacitor storage circuit 14 with a constant current of 125 A during this period. The inverter input voltage has dropped to a voltage DC300V, which is assumed to be the lower limit. During this time, the maximum power from the generator 11 is reduced to 74.6 kW. In the charging by the regenerative power at the time of descending, it is finally within DC 584V.

  As described above, by charging with a constant current from the generator 11 during the charging period of the capacitor storage circuit 14, the load of the generator 11 is leveled and the power generation capacity can be reduced. However, it is common for a cargo handling crane to lift and unload a load and the load operation is repeated in one direction. When loading a container on a ship, the cargo handling crane repeats the unloading operation. Therefore, the generator 11 is operated in accordance with the discharge from the capacitor storage circuit 14 to supply power in the constant current mode, and the power of the motor 17 is supplied from both. This is the control of the present invention. However, in this case, since the crane descends with no load, the regenerative electric power is charged only with potential energy corresponding to its own weight. Therefore, it is necessary to charge the generator 11 corresponding to the load energy when descending.

  Conversely, when unloading containers such as containers from a ship, the regenerative power at the time of descent is greater than the power consumption at the time of ascent with no load, so all the braking energy is absorbed by the limited storage capacity. It is not possible. Therefore, as a countermeasure, it is necessary to detect excess capacity of the capacitor and insert a power generation resistor through a switch to convert the surplus energy into heat. In this unloading work cycle, the power regenerated in the capacitor storage circuit 14 at the time of lowering becomes larger than the discharge power at the increased value, so that the generator 11 does not have to be operated.

  If the system as described above is used, the capacitor storage circuit 14 is charged with a constant current from the generator 11 during the discharge period of the capacitor storage circuit 14 when the load of rising and lowering of the cargo handling is balanced. The electric power is leveled, and the capacity of the generator 11 can be reduced. Further, by charging the capacitor storage circuit 14 with the generated power during the period of braking operation for the amount of storage of the capacitor storage circuit 14, it is possible to avoid an adverse effect, i.e., loss of remaining charge capacity, thereby preventing an increase in storage capacity. In addition, when unloading is continuously performed in one direction, the power necessary for maintaining the power of the capacitor storage circuit 14 is charged with a constant current controlled by the generator 11 when the crane descends, thereby increasing the capacity of the generator 11. Can be reduced. In addition, when unloading is continuously performed unilaterally, the regenerative power is generated and braked by the resistor, so that the action of the mechanical brake can be reduced, and an increase in the storage capacity can be avoided.

It is a figure which shows the circuit structure of the harbor cargo handling crane system which concerns on embodiment of this invention. It is a figure which shows operation | movement of the crane in the harbor cargo handling crane system which concerns on embodiment of this invention. It is a figure which shows an example of the operating curve in the harbor cargo handling crane system which concerns on embodiment of this invention. It is a figure which shows an example of the operating curve in the harbor cargo handling crane system which concerns on embodiment of this invention. It is a figure which shows an example of the operating curve in the harbor cargo handling crane system which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Diesel engine, 11 ... Generator, 12 ... Rectification circuit, 13 ... Charge control circuit, 14 ... Capacitor electrical storage circuit, 15 ... DC-DC conversion circuit, 16 ... Inverter circuit, 17 ... electric motor, 18 ... crane operating unit, 20 ... voltage detection circuit, 21 ... current detection circuit, 22 ... system control circuit, 31 ... ship, 32 ..Yard, 33 ... Load

Claims (3)

A generator having at least an engine as a power source; a rectifier circuit that converts electric power generated from the generator into direct current; an inverter circuit that converts direct-current power generated from the rectifier circuit into alternating current power; the rectifier circuit; A capacitor storage circuit that stores DC power to and from the inverter circuit, an electric motor driven by the output from the inverter circuit, a crane powered by the electric motor, and a voltage detection that detects a voltage applied to the capacitor storage circuit A circuit, a current detection circuit for detecting a current flowing through the capacitor storage circuit, and a system control circuit to which a detection signal from the voltage detection circuit and the current detection circuit is input, and based on two modes In the control method of the harbor handling crane system that controls the entire handling crane system ,
It is a mode to lift the load from a low place to a high place, the engine is always turned on and electric power is always generated by the generator , and the electric power stored in the capacitor power storage circuit is used as an auxiliary power. The crane is operated, and when the crane is stopped or the crane is turned, the electric power from the generator is rectified and charged to the capacitor storage circuit as a constant current source ;
In this mode, the load is lowered from a high place to a low place, the engine is appropriately turned on to generate electric power by the generator as needed, and the crane is operated mainly using the electric power stored in the capacitor storage circuit . The power is stored in the capacitor power storage circuit in advance, and the crane is lifted, and regenerative power generated by the potential energy of the crane descending is charged to the capacitor power storage circuit. An unloading mode in which the engine is turned on and the generator is operated and charged only when the quantity is less than
The system control circuit calculates a product of a voltage value obtained from the voltage detection signal transmitted from the voltage detection circuit and a current value obtained from the current detection signal transmitted from the current detection circuit, and It is determined whether the electric power tends to be stored in the capacitor power storage circuit or the power of the capacitor power storage circuit is consumed, and the power tends to be stored in the capacitor power storage circuit. If, it is determined that the unloading mode, when there is a tendency that the power of the capacitor storage circuit is consumed, the control method of the cargo handling crane system, characterized in that determining a landing mode. The method of controlling a harbor handling crane system according to claim 1, wherein regenerative electric power generated by the electric motor when the crane is lowered is stored in the capacitor storage circuit. The method for controlling a harbor cargo handling crane system according to claim 1 or 2, wherein regenerative electric power generated by the electric motor is consumed by a resistor when the crane is lowered.

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