DE2847406A1 - Automatic mooring winch system for ships - has winch drum driven by polyphase motor supplied from static converter with speed feedback - Google Patents

Abstract

The mooring system has a winch with a drum driven by a polyphase motor supplied from a static converter consisting of a static inverter and a rectifier. The motor's speed is monitored, eg. by a tachometer, and used to control the static inverter in order to change the motor's excitation. The monitor's output is connected to a detector designed so that the polarity of the signal from the monitor is preserved despite changes in the direction of rotation of the monitor as a result of a switch and parallel circuit path containing an inverting amplifier coupled into the actual speed feedback path.

Description

Automatic mooring winch device

(Addition to ... patent application P 27 53 729.7) the The invention relates to an automatic mooring winch device according to the preamble of claim 1 (addition to ... P 27 53 729.7).

The invention is an improvement on the patent ... (patent application P 27 53 729.7).

In this patent ... (patent application P 27 53 729.7) is the Winch motor continuously energized to torque for automatic mooring in the direction of the rope retrieval even when the ship's movement has a Issue of the rope conditional. This way the tension is maintained at all times. As before, a converter with a rectifier and an inverter is used.

For all normal automatic mooring work are the ship movements relatively low and the winch motor remains continuously in line with the rope retrieval when energized, as in the earlier device.

However, an amendment is made here according to which the motor speed by a tachometer generator or other device monitored and, if that Rope pulling ship movement exceeds a predetermined value, this is determined and the direction of motor excitation is reversed.

The motor is then excited in the sense of a rope output. However drives the motor continues, as in the previous case, a torque in the sense of a rope retrieval to withstand the pull-out movement of the rope and maintain tension.

The device preferably performs normal as well as automatic mooring work without the need for a different arrangement for power supply to switch as described in the previous case.

In the case of a mooring winch device, this improvement is described in the introduction mentioned type achieved in that the motor by a converter device is fed, which comprises a rectifier and an inverter, and that the speed of the motor by a device, e.g.

a tachometer generator, is monitored, and that a change in the Detector devices responding to the signal from the device are provided, to change the mode of operation of the inverter to change the direction of excitation of the Change engine.

The following is an embodiment of the invention based on Description of the drawing, which is a block diagram of the device.

The device comprises an AC squirrel cage motor 10, which drives a tachometer generator 300. The motor 10 is powered by an inverter 320 is fed with a quasi-square-wave current, which is similar to Is constructed in the same way as the inverter 120 already disclosed, although it in the present case a current inverter instead of the one described in the previous case Voltage inverter is.

The inverter 320 is via an inverter 322 by a Variable voltage constant direct current regulator 324 connected to a Three-phase AC power source 326 is connected.

The inverter 320 has six arranged in a bridge circuit Thyristors, which are activated by pulses from an electrical and the timing circuit already described can be generated. A detailed explanation of the inverter 320 and the direct current regulator, which the direct current »Downshift 106 and accordingly is similar to the circuit described in the previous case therefore not necessary.

The frequency of the output of inverter 320 is variable and is a feedback voltage signal is derived by the tachometer generator 300, which is related to the speed of the winch motor 10 is proportional. The feedback signal is used to determine the speed or speed of the winch motor 10 is used.

The signal is also used to control the DC regulator 324 used.

The device comprises a manually controllable device 330 to enter a "speed requirement", which during manual control the winch for purposes other than automatic mooring used to change the speed and direction of rotation of the winch.

The same control is set to maximum speed in the rope retrieval direction when the device is set to automatic mooring mode.

This "speed requirement" or "speed requirement" results in a "slip frequency requirement", which also leads to the current control so that the output current from the inverter 320 to the size of the "slip frequency requirement" is directly proportional.

The minimum output current from inverter 320 is controlled by a controller 332 for minimum current ", which is independent of the slip frequency is.

The output current from the inverter 320 is kept at the level which by comparing the required current value with the value of the current the main grid and to regulate the current fed to the inverter for reduction the difference to zero is required. In other words, in addition to a speed value feedback control is a current value feedback control used.

A reference to the drawing is sufficient for the control signal system, given the details of the derivation, comparison and abandonment of the various Signals required circuits are known.

In the figure, the following components represent the control signal system shown: Variable potentiometers 330, 332, 334 and 336 for adjusting the comparison voltage values, a variable resistor 338, which means for limiting the upper Represents current value, solid-state amplifier switching device 340, 342, 344, 345, 346 and 347, typically type 741 or 747, solid-state switching devices 354, 356 and 357, typically types 4016 or 4019, are a solid state device 358 of type 4046, rectifier devices 359 and 360, solid state summing devices 361, 362, 364, 366 and 368, a ramp device 365, detector devices 367 and 369, the first controlling a switching device 408 and the second controlling the switching devices 354, 356 and 357 controls, two voltage controlled oscillators 371 and 373 as well two drive devices 375 and 377.

Current transformers are used to generate a current feedback signal 370, 372.

The maximum speed of the winch motor 10 can be controlled by a control of potentiometer 334 can be adjusted. The maximum slip frequency can go through Regulation of the Potentiometer 336 can be adjusted. The signal from the tachometer generator 300 is via a first switching line 400 via the potentiometer 334 and the connecting member 362 are guided to the switching device 357. The signal arrives then either directly to potentiometer 336 or via amplifier 340, depending on the state of the switching device 357, inverted.

The signal from potentiometer 336 goes directly to the summing connector 364 and via the rectifier device 360 to the summing link 364.

The signal from the tachometer generator 300 is passed along a second conduction path 402 passed via the switching device 354 to the summing link 364 :, wherein the signal either reaches link 364 ummitfelbar, or through the Amplifier 347 is inverted depending on the state of switching device 354.

Thus, summing junction 364 receives over line 400 a first signal which is the difference between the actual speed of the motor and the required speed as set at 334. This difference is derived by link 362. The first signal is also representative of the direction of rotation of the motor, as set at 330. By the connecting member 364 receives a second signal input via the switching path 402, ' which represents the actual speed of the motor 10. The exit from summing link 364 becomes devices via device 342 377, where the DC voltage pulses at a repetition frequency which are generated by the voltage value of the generated by the connector 364 Signal are dependent. The pulses are sent to inverter 320 and activated or switching the thyristors used in the inverters. The consequence of activation is determined by the polarity of the signal generated by connector 364. As a result, the phase in which the motor 10 is fed is determined. The automatic mooring adjustment is one in which the motor is excited so that it is free from load runs in the rope hauling direction.

When the repetition frequency of the pulses from device 371 drops to 0.1 Hz during the automatic masking operation, the device generates 369 an output signal in the form of direct current voltage pulses, which is used for switching of devices 354 and 356 is used from one state to another.

Switching the device 356- changes the sequence of activation pulses, which are fed to the inverter 320, so that the phase of the motor supply is reversed.

The switching of the device 354 is effected such that the from Tachogenerator 300 is inverted via the line path 402 coming Siqnal, if regardless of the direction of the engine rotation, that by the link 364 from Connecting link 361 received signal consistently same polarity having.

The switching of the device-357 is effected in such a way that then, when approximately forward rotation of motor 10 is requested at 330, the signal passes the inverting amplifier 340 is passed, but the signal is passed directly to the Potentiometer 336 and thence to summing link 364 when reverse rotation is required.

The device 365 ensures that an excessively quick change in the. Direction.

the required rotation at 330 does not adversely affect the system influenced overall. The device 365 ensures a relative. even Rate of change of the signal, whatever the degree of change in the setting of the Device 330 is.

That. A signal representing the actual speed of the motor 10 is via the conduction path 406 via the switching device 408 (which responds to signals. from the device 367 responds) and the amplifier device 346 out. the Device 367 can only be actuated when the requested speed signal which is set at 330 exceeds a certain value.

The detector device 367 causes the device 408 to generate a signal to the amplifier 346 outputs which on the link 366 to the speed request signal is added. In this way, the non-linearity of the operating characteristic of the engine 10 will be charged.

The link 366-compares the required current as he does is represented by the voltage signal from the tachometer generator, with the minimum Current value, which is input at 332, and generates a corresponding output voltage signal. This output is amplified by device 344 and to the summing connector 368 led. Link 368 compares the signal for that effectively required Current received by the device 344 with the value of the from the Power grid received current, which value is detected by the transformers 370 and 372 will.

By device 359, one of the output of those transformers Directional alternating current voltage removed and via the variable resistor 338 led to connecting link 368.

The output from link 368 is passed through device 346 amplified and led to the regulator, from where to control the regulator like that used to be the difference between the required current and the actual one to reduce the current drawn to zero.

The operating mode for the automatic mooring operation is described below described. When the system is set to automatic mooring, the Control 330 set to maximum rope retrieval speed. I.e. the potentiometer sliding contact is moved to the extreme positive voltage end of the potentiometer. The middle Position represents the signal for zero speed, i.e. unexcited motor, and the opposite extreme position provides the excitation of the motor for one Rope output at full speed. The required motor speed is proportional to the distance to which the potentiometer slide from its mean Position is offset.

The winch then pulls in the rope until the tension in the rope is the same as that set Tension reached. The engine will then stall, i.e.

the motor 10 stops rotating, but is still excited in the sense of Rope retrieval and continuously develops a torque in this sense. The motor 10 'is excited at a frequency of about 2 Hz at which the winch is the set Tension continuous can give off without overheating.

The signal from the tachometer generator is now zero.

The signal from potentiometer 330 for the speed request is the only available control signal. From this signal control signals for the inverter 320 and the regulator 324 derived so as to a constant Maintain excitation of the motor 10. If the water level changes like this, that the tension of the Vertäuseils tends to decrease, turns the winch immediately in the sense of a rope retrieval.

A signal is generated by the tachometer generator 300. The signal is positive, as the direction of rotation is in the direction of retrieval.

The faster the movement of the ship in the direction of stress reduction acts, the faster the winch turns. Already in the mood with the winch movement also accelerates the tachometer generator and the generated signal has a size which represents the winch speed at any point in time.

The generated signal embodies an increase in the 1, speed requirement11 and the inverter thistors are now operated in a rapidly accelerated sequence, so that the motor 10 is energized at an increased frequency. The "speed request" which, as described, is fed back causes the increase in the feed frequency so, so that there is a constant tendency to reduce the slip frequency in order to reduce it to hold at the value of about 2 Hz.

As soon as this slip frequency is built up again, the engine speed remains constant.

The winch hauls in rope to maintain tension and up the movement of the ship decreases and-the rope tension is once more on the "set" Value returned. The speed of the winch rotation then decreases to Zero. The signal from the tachometer generator is also reduced to zero and the excitation frequency of the motor is reduced accordingly in order to maintain the nominal value of the slip frequency. The voltage is kept essentially constant over this entire operating phase.

Should. the movement of the ship due to the movement of the water or the wind power be such that the rope tension very easily over the set If the tension rises, the winch turns in the sense of a rope output. The engine 10 will inevitably moved against the direction of excitation.

However, the motor still delivers torque and maintains the rope tension to a 'value which is very close to the set value. If the motor rotates in the rope output direction, the tachometer generator generates a negative one Voltage signal which reduces the "required speed" signal.

As a result, the repetition frequency of the pulses from the device becomes 358 reduced.

The supply frequency to the motor is reduced.

Should be the speed of the motor rotation in the rope payout direction reach a sufficient value, the frequency of the pulse repetition falls on Output of oscillator 371 to 0.1 Hz, so that the output from amplifier 342 suddenly switches to fully negative output, which is detected by device 369, which causes the devices 354, 356 and 357 to switch.

The circuit sequence of the hydrofistors of the inverter 320 is changed, so that the phase of supply is reversed.

Switching the device 354 causes the negative voltage signal running from tachometer generator 300 through inverting amplifier 347 to on link 364 to generate a positive signal.

Switching the device 357 causes the output from the link 362 is switched by the inverting amplifier 340 to change the polarity of the signal from the tachometer generator 300 to compensate. The result is that when it grows the engine speed with the continued movement of the ship, the rope is paid out, the slip frequency determined by the system is a negative slip frequency and the system responds in a manner to the magnitude of the negative slip frequency to hold at face value.

The motor is fed with an increasing frequency when the motor speed increases, with the frequency determined by the system having a negative slip frequency is and the system responds in a way to the size of the negative slip frequency to hold at face value.

The motor is fed with an increasing frequency when the motor speed increases, the frequency being such that the motor continues to torque generated in the direction of the rope retrieval, which counteracts the movement of the winch drum, the winch now works in the same way as an electric winch when a load is lowered will. This operating mode is also called the "fourth quadrant" operating mode. energy is entered into the winch device by the ship and the inverter source releases energy into the power grid.

The device can be designed such that a constant moment of resistance is generated when the rope is paid out in order to maintain a constant tension in the distribution part to preserve. Alternatively, the device can be designed such that a increasing section modulus is generated when the rope is paid out to a To cause an increase in rope tension.

Ultimately, however, the rope tension must be limited for safety reasons and the device will be designed to prevent the Torque exceeds a safety value.

When the ship's movement decreases, the rope tension and the engine speed decrease to zero.

The signal from the tachometer generator 300 decreases so that the Feed frequency is reduced accordingly. Eventually it’s through the device 358 generated pulse frequency to 0.1 Hz, the detector 369 responds and causes the switching back of the devices 354, 356 and 357 in their original State.

Should the movement of the ship continue in the same sense, will turn the winch in the rope hauling direction to retrieve rope and in the rope maintain a substantially constant tension. The ship will then tend to stay in a fixed position or become tight-fitting in the original Move the mooring position.

During normal conditions it will be when the winch is on automatic mode set rist, the ship's movement will be relatively small and with relatively smaller Amplitude go ahead, as already described in the associated application. The present winch will carry out automatic operation under such conditions while she'continuously energized in the rope retrieval direction, the signal from the tachometer generator 300 never reaches a sufficiently negative value to cause devices 354, 356 and 357 and reverse the direction of excitation of the motor 10.

The relationship between the tension in the rope and the speed of rotation of the engine 10 in the described embodiment is through the devices 348, 352 and 353 determined, whereby the voltage corresponding to their design can be kept constant in the rope or, alternatively, increasing if the Winch must spend rope as mentioned above.

When the winch is hauling in rope, the device preferably holds the set voltage, however, can be achieved by appropriate design of the devices 348, 352 and 353 a different ratio can be selected. -The winch device described above also carries out a non-automatic or other pigeon operation, with the direction and speed of motor 10 manually by adjusting potentiometer 330 can be controlled.

When the rope is first issued for attachment to the mooring the winch can be adjusted by moving the potentiometer slide against the negative End of potentiometer set up to maximum rope payout speed will.

Claims (5)

Claims: a. Automatic mooring winch with a a winch comprising a winding drum, which is driven by a polyphase AC motor is driven by a multiphase alternating current jellyfish, characterized in that that the motor (10) is fed by a converter device which has a Rectifier (324) and an inverter (320), and that the speed of the motor (10) is monitored by a device such as a tachometer generator (300) and that one responsive to a change in the signal from the device (300) Detector device (D2) is provided to monitor the mode of operation of the inverter (320) to change the direction of excitation of the motor (10). 2. Apparatus according to claim 1, characterized in that the detector device (D2) is designed in such a way that the polarity of the signal from the device (300) to be maintained despite a change in the direction of rotation of the device (300) a switch (354) and parallel circuit paths, one of which is an inverting, into the actual speed feedback path arranged Includes amplifier (347). 3. Apparatus according to claim 1 or 2, characterized in that the detector device (D2) is designed in such a way that the pulse is generated by a To change the pulse generator (377). 4. Apparatus according to claim 1, 2 or 3, characterized in that that the detector device (D2) is set up in such a way as to detect the polarity of the signal to be maintained by the device (300) despite a change in the direction of rotation of the device (300) by a switch (357) and parallel circuit paths, of one arranged in the control path for the required speed inverting amplifier (340). 5. Apparatus according to claim 1, 2, 3 or 4, characterized in that that the non-linearity of the motor characteristic is determined by the detector device (D1) which is used to modify the signal in the current feedback path (344, 368, 345, 373, 375) to the rectifier (324) is formed.