FI123242B - Procedure and arrangement for use of winch - Google Patents

Description

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Method and arrangement for operating the winch

FIELD OF THE INVENTION

The invention relates to a method and arrangement for driving an electric motor driven winch.

BACKGROUND OF THE INVENTION

Winches used on ships or other vessels or in ports, such as anchor winches, mooring winches or towing winches, are generally driven by hydraulic systems. However, the use of hydraulic systems presents a potential risk of contamination or damage to the cargo being transported in the event that the hydraulic oil used by the hydraulic system escapes from the system. In addition, hydraulic systems typically require continuous operation to keep the system pressurized. This consumes energy. For these reasons, electronic systems are becoming more common in the propulsion of ships and similar winches. Electric drives that drive the winches with one or more electric motors are simple to install and control during operation. In addition, electric drives are maintenance-friendly and can provide significant energy savings and increase the reliability of winch drives.

The electric drive, comprising the motor and the inverter supplying it, provides the ability to control the speed of rotation of the motor and the torque it produces, and thereby the drive speed and torque of the winch driven by the motor. When operating below the rated motor frequency, the so-called "motor" frequency. in the constant flow range and the corresponding rotational speed range, the maximum torque produced by the engine can be kept constant. When operating above the nominal frequency of the motor nominal-25, there is a so-called. in a field weakening situation where there is no possibility of increasing the speed by increasing the input frequency and voltage of the motor, but the only way to increase the frequency is to keep the voltage constant and thereby reduce the excitation. However, weakening the magnetization in this way rapidly reduces the engine's ability to generate torque, i.e. the maximum torque produced by the 30 engines decreases as the speed increases above nominal.

In winch drives, there may be situations where it would be advantageous to operate the winch and the motor driving it at higher than rated speeds. For example, when driving a ship's rope in or out with the rope unloaded 35, it is preferable that it be made at a higher speed than the nominal. However,

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Also, since the maximum torque produced by the engine decreases as the speed increases, ofla may need to limit the speed of the winch and the engine in the event of torque being applied to the engine. This can be done by always limiting the engine speed according to the torque 5 applied to the engine in each case.

The problem with the above solution is that such a limited speed may lead to a situation where, when driving the winch out of the engine, the torque obtained is no longer sufficient to stop the winch.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the invention to provide an apparatus so that the above problem can be solved or at least alleviated. The object of the invention is achieved by a method, a computer program product and an arrangement characterized by what is stated in the independent claims 1, 5 and 6. Preferred embodiments of the invention are the subject of the dependent claims.

The invention is based on limiting the maximum speed of electric drive in reverse operation, in which the electric motor drives the winch outwards, further on the basis of a predetermined first torque buffer value.

An advantage of the solution according to the invention is that the solution can take into account any additional torque needed to reduce the speed of the winch and / or to stop the acceleration of the accelerator during reverse operation of the winch drive.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in more detail in connection with preferred embodiments, with reference to the accompanying drawings, in which: Figure 1 shows a block diagram of an arrangement according to one embodiment; Fig. 2 shows an example of a rotation speed-torque curve; ^ 30 and tn ^ Fig. 3 shows a diagram of limiting rotation speed according to one embodiment, δ

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DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 is a block diagram of an arrangement according to one embodiment. The figure shows only the components essential to an understanding of the invention. The arrangement of the figure comprises a winch 20, which may be exemplary of a ship or other vessel, an oil or gas rig or a port winch such as, for example, anchor winch, mooring winch or towing winch. The winch 20 may comprise a rope, a wire, a chain or the like (not shown separately) which can be wound inwardly and outwardly by the winch. The winch 20 is driven by an electric motor 30 for rotating the winch. The motor 30 may be an asynchronous motor, such as a short-circuit motor, or a synchronous motor or a DC motor. Further, the invention is not limited to any system using a particular frequency or to any particular voltage level. In the example of Fig. 1, motor 30 is a short-circuit motor fed by inverter 60 from DC source 70. The inverter is a device used, for example, to control 15 motors, and inverter 60 can control power output from DC 70 to motor 30. By means of the inverter 60, the motor 30 can be controlled in a reliable manner so that the motor executes precisely the desired speed or torque reference, for example. The exemplary arrangement further comprises a separate control unit 40 which can be used to control the inverter 60 and thus the motor 30 and the winch 20. The control unit may also receive the necessary information from inverter 60 and motor 30, such as motor speed information or torque information on the motor. The control unit 40 may also be part of the inverter 60 or some other unit. The control unit 40 may be associated with one or more I / O (Input-Output) devices 50 comprising e.g. a display and a keyboard and providing a user interface to the control unit 40. Thus, the system user may, for example, control the winch 20 and change system parameters through the user interface. The control unit 40 may also comprise, in addition to or instead of a separate I / O device, suitable I / O means for providing a user interface to the user.

According to one embodiment, the winch 20 may be operated to drive the electric motor 30 in forward motion to drive the winch 20 inward, and in the reverse operation to drive the electric motor 30 outwardly to drive the winch 20. In other words, in the forward operation, the winch 20 ke-35 winds the associated rope, wire, chain or the like inward, and in the reverse operation, the winch 20 winds the associated rope, wire, chain or 4

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similar outward. The torque applied to the electric motor 30, i.e. in practice the torque applied by the winch 20 to the motor 30, is preferably determined substantially continuously. The torque determination can be done in some manner known per se, for example in inverter 60 and / or control unit 40. Existing inverters may have a built-in torque determination function which can be utilized in this context.

The maximum rotation speed of the electric motor 30 is preferably limited based on the specified torque and predetermined parameters. Preferably, the predetermined parameters determine the maximum allowable rotation speed of the electric motor 30 depending on the torque applied to the motor. According to one embodiment, such predetermined parameters may comprise two or more points defining a rotational speed-torque curve by which the maximum speed of the electric motor 30 is limited. Such a rotational speed-torque curve may comprise a forward-motion curve portion and a rearward-curve portion, each curve portion being determined by two or more points. The points defining the curve are preferably adjustable by the system user. In this way, the user is able to determine the system of the curve according to the respective requirements. Fig. 2 shows an example of a rotation speed-torque curve. It should be noted that the curve in Fig. 2 is only one example of a rotational speed-torque curve and the curve shape may deviate from that shown in the figure. The vertical axis represents the torque as a percentage of the motor's maximum rated torque (100%) and the horizontal axis represents the 25 engine speeds. The forward portion of the forward-torque curve of the rotational speed-torque curve of Fig. 2 is determined by points 1-5. The points on the curve between points 1-5 are obtained, for example, by interpolation. Correspondingly, the curve of the reverse function of the rotation speed torque curve is determined by points 6-10. There could be more or less points defining the curve than shown in the example in the figure. The forward-curve portion of the rotation-torque curve and the curve portion of the reverse-rotation operation may be different or similar (mirror images) depending on the system to which the invention is applied. The curve of the example of Fig. 2 can be used to limit the rotation speed of the motor 30 by retrieving from the curve the maximum rotational speed value corresponding to the torque applied to the motor and limiting the maximum rotation speed of the motor 30.

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up to this value. According to one embodiment, there may be two or more groups of predefined parameters such that there is always one set of parameters in each case and the group can be changed, if necessary, for example during operation or when system properties change. Thus, there may be two or more rotational speed-torque curves defined by the parameters, respectively, and the speed is always limited according to the selected curve. The parameter groups can be stored as profiles, for example in the control unit 40 or in the memory connected thereto, and the parameter group (profile) to be used is preferably selected by the user of the system 10. It is also possible that the system selects the parameter group (profile) to be used according to a predetermined condition or conditions.

According to one embodiment, the reverse engine operation further limits the maximum rotation speed of the electric motor 30 on the basis of a predetermined first torque buffer value 15. Preferably, the first torque buffer value corresponds to at least the torque required to slow down the running speed. In this way, the first torque buffer value ensures that the reverse speed can begin to slow down. According to one embodiment, when running at 20 accelerating speed in reverse operation, the maximum speed of the electric motor is further limited based on a predetermined second torque buffer value. The second torque buffer value corresponds to the torque required to stop the acceleration of the running speed. In this way, the second torque buffer value ensures that the acceleration of the driving speed can be stopped when driving in reverse gear at accelerated speed. It is also possible to use only one (first) buffer value in reverse operation, which is set to correspond to both the torque required to slow down the driving speed and the torque required to stop the acceleration of the driving speed. However, the use of two buffer values has the advantage 30 that the speed limits can be more closely adapted to the driving situation, since the torque buffer required for reversing at accelerating speed is typically larger than otherwise for reversing. The required buffer values are determined on a case-by-case basis according to the system characteristics. Preferably, the buffer values are user-adjustable by the system user. This allows the user to configure 6

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buffer values according to the system's current requirements and to modify them if changes occur in the system that affect buffer values.

Figure 3 illustrates an example of limiting rotation speed according to one embodiment when using two torque buffer-5 values. The functionality shown in Fig. 3 may be included, for example, in the control unit 40. The selection unit 41 initially receives input of the state in which the winch is driven. Alternative modes include: forward operation 11, reverse operation at accelerated speed 12, reverse operation at constant speed 13, and reverse operation at decelerating speed 14. The selector unit 41 selects the reference torque to be used for speed limitation based on this. In the case of winch forward operation, the torque TQ applied to the motor 30, which is defined as the torque reference, is selected. Conversely, in the case of reverse operation 12, 13 or 14, the torque TQ applied to the engine is determined as the torque reference and the first torque buffer value TDECB added thereto, which preferably corresponds to the torque required to slow down the running speed. In addition, in the case of reverse operation at accelerating speed 12, another torque buffer value TACCB is added to the torque reference value, which preferably corresponds to the torque required to stop the acceleration of the driving speed. Thus, when the operating condition of the winch is reverse operation at constant speed 13 or reverse operation at decelerating speed 14, the torque reference value is formed as TQ + TDECB. Whereas the mode of operation is reverse operation at accelerating speed 12, the torque reference is formed as TQ + TDECB + TACCB. Preferably, the selected torque reference value is further filtered through filter 42. The purpose of any filtering is to filter out any instantaneous variations from the torque reference value. The filtered torque reference TQREF thus obtained is further fed to a speed limiting unit 43 which, for example, based on the rotation speed-torque curve (or para-30 meters) defining the torque reference value TQREF, corresponds to the maximum rotation speed ΔX. Thereafter, the maximum value of rotation speed of the motor 30 is limited to PSMAX.

According to one embodiment, the rotational speed limiting function described above may, if necessary, be deactivated, for example, by a user. Thus, for example, the system user is preferably able to, if necessary 7

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disable or enable the speed limiter function, for example, while driving the winch 20.

The apparatus implementing the various embodiments described above and the various combinations thereof, such as the control unit 40, may be implemented by one or more units. The term "unit" generally refers to a physical or logical entity, such as a physical device or part thereof, or a software routine.

The hardware according to various embodiments, such as the control unit 40, may be implemented, at least in part, by a computer or equivalent sig-10 signal processing equipment with appropriate software. An example of a suitable signal processing equipment is a Programmable Logic Controller (PLC). Such a computer or signal processing apparatus preferably comprises at least a working memory (RAM) providing a storage area utilized by arithmetic operations and a processor (CPU) such as a general purpose digital signal processing processor (DSP) performing arithmetic operations. The processor may comprise a plurality of registers, an arithmetic logic unit and a processor control unit. The processor control unit is controlled by a series of program commands that are transferred to the processor from the working memory. The processor control unit may comprise micro instructions for basic operations. 20 The implementation of micro-commands may vary depending on the processor structure. Program instructions can be encoded in a programming language, which can be a high-level programming language such as C, Java, etc., or a low-level programming language such as machine language or assembler. The computer may also comprise an operating system that may provide system services to a computer program written by program instructions. The computer or other apparatus implementing the invention or a part thereof, such as a control unit 40 or the like, preferably comprises suitable input means 50 for receiving control or measurement data from the user and / or other devices and output means 50 for printing alarms and notifications and / or control information device control. The apparatus 30 further preferably comprises a suitable user interface 50 through which, for example, the user can set the required parameters. It is also possible to use special integrated circuits, such as ASIC (Application Specific Integrated Circuit), and / or dedicated components or other devices to implement the functionality of the various embodiments according to the various embodiments.

35 The various embodiments described above may be implemented in existing systems such as electric drives or components thereof such as interchangeable 8

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and / or use separate elements and devices in a centralized or decentralized manner. Existing devices for electrical drives such as inverters and inverters typically include a processor and memory that can be utilized to implement the functionality of the various embodiments. Thus, the changes and configurations required to implement the various embodiments can be accomplished, at least in part, by software routines, which in turn can be implemented as added or updated software routines. If the functionality of the various embodiments is implemented by software, such software may be provided in the form of a computer program product comprising computer program code which is executed by the computer program code on the computer to perform the functionality of the invention according to the various embodiments described above. Such computer program code may be stored or generally included in a computer readable medium such as a suitable storage medium, for example flash memory 15 or optical memory, from which it can be read to the unit or units executing the program code. In addition, such program code may be downloaded to the unit or units that execute the program code through a suitable data network and may replace or update any existing program code.

It will be obvious to one skilled in the art that as technology advances, the inventive concept can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

Claims (11)

2101036FI A method of operating an electric motor driven winch, the method comprising: controlling the electric motor (30) to drive the winches 5 (20) inward; controlling, in reverse operation, the electric motor (30) to drive the winch (20) outwardly; determining the torque applied to the electric motor (30); and limiting the maximum speed of the electric motor (30) on the basis of the specified torque and predetermined parameters, characterized in that the method comprises: further limiting the maximum speed of the electric motor (30) on the basis of a predetermined first torque buffer value; and 15 is further limited in the reverse operation at accelerating speed by driving the maximum speed of the electric motor (30) based on a predetermined second torque buffer value and the second torque buffer value corresponding to the torque required to stop the acceleration of the driving speed. Method according to Claim 1, characterized in that the first torque buffer value corresponds at least to the torque required to slow down the running speed. Method according to Claim 1 or 2, characterized in that the predetermined parameters comprise two or more points defining a rotational speed-torque curve by which the maximum speed of the electric motor (30) is limited, δ A method according to claim 3, characterized in that the (M +) and the torque-torque curve comprise a forward portion of the forward operation curve and a backward operation portion of the curve, each curve portion being determined by two or more points. £ 5. A computer program product comprising computer program code whose execution of a computer instruction code on a computer causes the computer to perform the steps of one of the claims 1-4, An arrangement for driving a winch driven by an electric motor, the arrangement comprising control means (40) adapted to: in forward motion drive the electric motor (30) to drive the winch (20) inward; to control, in reverse operation, the electric motor (30) to drive the winch (20) outward; and 5 to limit the maximum rotation speed of the electric motor (30) based on the torque applied to the electric motor and predetermined parameters, characterized in that the control means (40) are adapted in reverse operation to further limit the maximum rotational torque of the electric motor (30); and the control means (40) is adapted to reverse the maximum speed of the electric motor (30) in reverse operation on the basis of a further predetermined second torque buffer value and the second torque buffer value corresponding to the acceleration stop speed required. An arrangement according to claim 6, characterized in that the first torque buffer value corresponds at least to the torque required to slow down the running speed. Arrangement according to Claim 8 or 7, characterized in that the predetermined parameters comprise two or more points defining a rotational speed-torque curve on the basis of which the control means (40) are adapted to limit the maximum rotation speed of the electric motor (30). Arrangement according to Claim 8, characterized in that the rotation speed-torque curve comprises a forward portion of the forward curve and a reverse portion of the backward operation, wherein each portion of the curve is determined by two or more points. Arrangement according to one of Claims 8 to 9, characterized in that the winch (20) is a winch for use on a ship or in a port, An arrangement according to claim 10, characterized in that the winch (20) is an anchor winch for a ship. winch or towing winch. 05 h'- LO o o C \ l