SU843139A1 - Method and device for control of load-handling mechanism self-sustained dc drive - Google Patents

Description

The invention relates to electrical engineering and can be used to drive the hoist winch rigs, construction cranes and dru-, GIH similar mechanisms, in which the individual ^e DC generator is driven to rotate the internal combustion engine.

For generators driven by the motor of internal him- ^υ Rania, energy is the most feasible mode of constant power mode. Moreover, below the main frequency of rotation of the motors, regulation is carried out due to 15 regulation of the excitation current of the generator at the rated excitation current of the electric motor, and at the rated excitation current and voltage of the generator, a further increase in the frequency of rotation is made by reducing the excitation current of the electric motor.

There is a known method of controlling an electric drive, in which the excitation current 25 is regulated as a function of the armature current, the task is set to the maximum permissible armature current as a function of the excitation current, and the excitation current is limited when the voltage at the motor armature exceeds the permissible level G1? .

A device for implementing this method comprises adjustable converters in the armature circuit of the electric motor and in the field winding circuit, an armature feedback circuit with a limitation adjustable as a function of the field current, armature current sensors, voltage and field current sensors, a functional converter connected between the armature current sensor and the input controlled inverter circuit excitation winding to an input ¹ which is in series with the nonlinear element is connected a voltage sensor output, and a logic element Serving for adjustment of the excitation current, depending on whether a motor or brake mode is electric.

Regulation of the excitation current as a function of the armature current over the entire range of load and velocity changes provides an increase in the use of the dynamic properties of the electric motor, as well as a slight approximation of the shape of the mechanical characteristics to the characteristics of constant power.

However, this approximation of the shape of the characteristics to the characteristics of constant power is not enough. In addition, this device does not take into account the effect of the voltage at the armature on the switching of electrical machines. 5

Closest to the proposed one is a method in which the excitation current of the electric motor is regulated as a function of the armature current, the task is set to the maximum permissible current "d of the armature as a function of the excitation current and the amplitude of the voltage at the armature of the electric motor G2].

A device that implements this method comprises a unit for setting the rotational speed of the electric motor, a rotational speed regulator in series with a limiting unit in its feedback circuit, and a current regulator with a rotational speed sensor and an armature current sensor 20 in the generator control system supplying the motor armature , exciter., electric motor, in the control circuit of which an excitation current regulator is included, two non-linear elements with a dead zone and output limitation with the needle on the lower and upper levels, one of which is connected between the current sensor of the armature and the second input of the excitation current controller, and the other between the sensor of the excitation current and the adder, the second input of which is connected to the voltage sensor at the armature through the module selection unit, and the output the control input of the restriction unit in the feedback circuit of the speed controller.

The well-known technical solution, designed for use, first of all, in relatively powerful electric networks * ^ 0 does not provide without. shock work of the lifting mechanism during operation of the primary engine with the highest possible Efficiency. 45

The purpose of the invention is the provision of shock-free operation of the lifting mechanism during operation of the primary engine with the highest possible efficiency. jq

This goal is achieved by the fact that in the known method additionally determine the magnitude of the tension of the hoisting rope and the dynamic component of the electric motor moment at a rope tension less than that corresponding to the empty hook, form the signal with the maximum magnitude, and when the tension is greater than or equal to the tension force corresponding to the empty hook 60, this signal is formed proportional to the tension * summarize the received signal with a signal proportional to the dynamic component of the electric motor moment of Tell and inversely proportional to the signal summation result setpoint change limit motor speed.

In the device, the goal is achieved by 5 introducing a proportional amplifier with a restriction block in its feedback circuit, a rope tension sensor, a nonlinearity block with a hyperbolic characteristic, a threshold element, an adder made in the form of an operational amplifier with a zener diode in the feedback circuit, and a speed differentiation signal differentiation unit, while the proportional amplifier is connected between

5. the unit for setting the speed and the speed controller, and to its control input through the series. A threshold element *, an adder, and a nonlinear element with a hyperbolic characteristic are connected, a rope voltage sensor is connected, the output of which and the output of the differentiation unit are connected to the inputs of the adder.

The method is carried out as follows.

Measure the tension of the rope of the lifting device and, depending on the magnitude of this force, generate a signal so that it is maximum when the tension of the rope is less than when the hook of the lifting device with its own hanging on the rope, and when the tension of the rope is equal to or greater , the tension force with a hook hanging on the rope with the reinforcement, the aforementioned signal was proportional to the tension force of the rope. At the same time, the frequency of rotation of the motor armature is measured, 0 the received signal is differentiated and summed with the signal received earlier, forming a signal proportional to the total moment of the motor. in the function of the signal, which is inversely proportional to the total moment of the electric motor, the task is limited to the maximum permissible frequency of rotation of the electric motor. The signal for setting the frequency of rotation of the electric motor is compared with a signal proportional to the frequency of rotation of the electric motor, and the maximum is limited. the magnitude of the obtained difference in the function of the signals of positive feedback on the excitation current and. negative feedback modulo the voltage at the armature, and the resulting signal is compared with signals proportional to the armature current, and is used as a signal for setting voltage O at the motor armature. In addition, a signal proportional to the current of the armature of the motor is limited at the upper and lower levels and is used as a signal for setting the excitation current of the motor.

The specified method can be implemented in a device, a diagram of which is shown in the drawing.

The anchor circuit contains an electric motor armature 1, which is connected in series with the input of the armature current sensor 2 to the generator armature 3, the excitation coil 4 of which is connected to the output of the generator exciter 5. Anchor 3 of the generator is located on the same shaft with the prime mover. The output of the armature current sensor 2 is connected to the input of the armature current controller 6 and sequentially with the nonlinearity block 7 having a dead zone, the excitation current regulator 8 • is connected to the input of the gate exciter 9, to the output of which the winding 11 is connected in series with the input of the excitation current sensor 10: Kdeniya electric motor. The output of the armature current controller 6 is connected to the input of the pathogen 5, and the input of the armature current controller 6 is connected to the output of the speed controller 12 and to one of the AC inputs of the restriction unit 13, the second AC output of which is connected to the first input of the speed controller 12, and the DC outputs of the restriction unit 13 are connected counterclockwise to the output of the adder 14, the first input of which is connected in series with the nonlinearity unit 15 having an aeon of insensitivity, ^ the output of the excitation current sensor 10, and the second the input of the adder 14 is connected in series with the isolator of the module 16 to the output of the voltage sensor 17, the input. which is connected parallel to the armature 1 of the electric motor. The second input of the speed controller 12 is connected, together with one of the AC inputs of the restriction unit 18, to the output of the proportional amplifier 19, to the first input of which the output of the speed setting unit 20 is connected, and the second AC input of the restriction unit 18 is connected to the second input of the amplifier 19. The DC output of the restriction unit 18 is turned on in the opposite direction to the output of the non-linearity unit 21 c. hyperbolic characteristic, the input of which is connected to the adder 22 and the zener diode 23, the anode of which is connected to one of the inputs of the adder 22. To the other inputs of the adder 22 is connected the direct current output of the sensor 24 of the rope tension (weight on the hook) directly and through the threshold element

25. The fourth input of the adder 22 is connected to the output of the differentiation unit 26, the input of which is connected to the speed sensor 27.

The device operates as follows.

In the absence of voltage at the output of the task unit 20 and, consequently, a proportional amplifier 19 and the presence of a load on the hook in case of mechanical brake release in the armature circuit of the generator and electric motor. current flows due to the acceleration of the motor armature 1 under the action of a pulling load on the hook. When accelerating the motor, a signal appears at the output of the speed sensor 27. This signal causes the signal at the output of the regulator 12, the rotational speed, which, acting on the input of the current controller 6 _f causes, in turn, the occurrence of such a signal at its output, which opening exciter 5 generator causes (increase braking current in the armature / chain Under the action of current in the anchor circuit, a signal will appear at the output of the armature current sensor 2, which will suppress, if necessary, the residual magnetization of the generator, as well as an increase in the signal at the output of the nonlinearity block 7, reg insulator 8, the driving current of the motor exciter 9 and increasing the excitation coil current 11 and the braking torque of the electric motor, whereby the rotational speed of the armature 1 will be negligible.

If there is a load on the hook of the lifting device and, therefore, a relatively large signal at the output of the sensor 24, the maximum signal will be at the output of the adder 22 and the non-linearity block 21.

When a reference signal is given for lifting the load from the output of the reference unit 20, a voltage appears at the output of the proportional amplifier 19, which can be at U _{e (j |) <fe} <ΙΙ _β6ιχ . proportional to the job or limited by the voltage backwater block 18 restrictions, i.e. voltage at the output of block 21 nonlinearity. Under the action of the voltage from the output of the amplifier 19, the voltage at the inputs and outputs of the speed controller 12, the armature current controller 6 of the armature exciter 5 changes. The voltage at the output of the controller 12, which is a reference to the armature circuit current, is limited by the block, 13 restrictions, voltage the backwater of which is determined by the signals at the input of the adder 14, formed in accordance with the laws of switching using block 15 of nonlinearity from a signal proportional to the excitation current and taken from the output of the sensor 10 current uzhdeniya, extractor 16 and voltage module, which is fed to the input signal from the sensor 17 output voltage. After the growing moment of the electric motor, due to the increase in the armature current and the excitation current, exceeds the load moment, the motor starts to accelerate. A signal will appear at the output of the differentiation block 26, which will increase the signal at the output of the adder 22 and the input of the nonlinearity block 21. As a result of this, the signal at the output of the non-linearity block 21 will decrease, which will lead to a further limitation of the signal at the output of the amplifier 19 and? limiting the load of the prime mover. As the motor accelerates and the dynamic component of the moment decreases on its shaft, the total load on the primary motor * shaft decreases, therefore, the signal at the output of the adder 22 decreases and the signal at the output of the non-linearity block 21 increases, which leads to blocking of the restriction block 18, and the signal the output of the amplifier 19 will be determined only by the speed reference signal.

, If at the beginning of the acceleration the ropes had slack, then the signal at the output of the sensor 24 will be zero, and therefore at the output of the threshold element 25 there will be 25 the maximum signal, which will condition the signal at the input of the speed controller 12 at a minimum level and therefore minimum rope jerk after finishing slack selection.

. Thus, implemented by introducing a limitation of the power of the prime mover in high load conditions on the motor shaft, i.e. ensuring the operation of the primary engine in the mode with maximum efficiency, the efficiency of the system as a whole is increased and at the same time such regulation provides a limitation of rope jerks and impacts when choosing slacks.

Claims (2)

The invention relates to electrical engineering and can be used to drive hoisting winches of drilling rigs, construction cranes and other similar mechanisms in which an individual DC generator is driven by an internal combustion engine. For generators driven by internal combustion engines, the most vigorous mode is the constant power mode. Moreover, below the main rotation frequency of the motors, regulation is performed by adjusting the generator excitation current at the rated excitation current of the electric motor, and at the rated excitation current and the generator voltage, a further increase in the rotation frequency is due to a decrease in the excitation current of the electric motor. There is a known method of controlling an electric drive, in which the excitation current is controlled as a function of the current of the core, the reference is set to the maximum allowable current of the core as a function of the excitation current and the excitation current is limited If the voltage is exceeded, on the motor core an acceptable level Til. The device for implementing this method contains adjustable transducers in the electric motor circuit and in the depot of its excitation winding, a feedback circuit with a controllable limitation adjustable as a function of the excitation current, and a transducer for the current, an input current connected between the current sensor. the core and the input of the adjustable converter in the field of the excitation winding, to the input of which, in series with the nonlinear element, the output of the voltage sensor, as well as a logic element m and serving to adjust the drive current depending on a braking or motoring mode is electric. Regulation of the excitation current as a function of the current over the entire range of load and speed variations provides increased utilization of the dynamic properties of the electric motor, as well as some approximation of the forv; mechanical characteristics to characteristics of constant power. However, this approximation of the shape of the characteristics to the characteristics of a constant power is not enough. In addition, this device does not take into account the effect of the voltage on the bark on the commutation of electrical machines. The closest to the proposed method is to regulate the excitation current of the motor as a function of the current of the core, regulate the reference to the maximum allowable current of the core as a function of the excitation current and the amplitude of the voltage on the core of the electric motor r2jf. A device that implements this method contains a motor speed setting unit, a rotational frequency controller connected in series with a limitation unit in its feedback circuit, and a current controller with a rotation frequency sensor connected to their inputs and a core current sensor in the control system the generator that powers the motor, the causative agent, the motor, in the control circuit of which the field current regulator is turned on, two nonlinear elements with the dead zone and the output bias drove through the lower and upper levels, one of which is connected between the current sensor core and the second input of the excitation current controller, and the other between the excitation current sensor and the adder, the second input of which is connected to the core voltage sensor and output - with the control input of the limiting unit in the feedback circuit of the rotational speed regulator. The well-known technical solution, designed for use, first of all, in relatively powerful electric networks, does not provide unaccented operation of the load-lifting mechanism during the operation of the prime mover with the highest possible efficiency. The purpose of the invention is to provide a shock-free operation of load-lifting meganism during the operation of the prime mover with the highest possible efficiency. This goal is achieved by the fact that in a known method, the tension of the lifting rope and the dynamic component of the torque of an electric motor are additionally determined when the tension of the rope is less than that of an empty hook, and when the tension is greater than or equal to The tension corresponding to the empty hook, form this signal proportional to the tension, sum the received signal with the signal proportional to the dynamic component of the moment. l and inversely proportional to the signal summing result, alter the setpoint limit motor speed. In the device, the goal is achieved by introducing a proportional amplifier with a limiting unit in its feedback circuit, a cable tension sensor, a nonlinearity block with a hyperbolic characteristic, a threshold element, a sug / beeator, made in the form of an operational amplifier with a zener diode in a reverse circuit. connection, and the differentiation unit of the rotational speed sensor signal, wherein the proportional amplifier is connected between the speed setting unit and the rotational speed regulator, and to its control input through Tel'nykh connected threshold element, an adder and a nonlinear element connected to a hyperbolic characteristic of the sensor voltage of the rope, which output and differentiating unit connected to the inputs of the adder. The method is carried out as follows: 3 O1L. The tension force of the rope of the lifting device is measured and, depending on the magnitude of this force, form a signal in such a way that it is maximum when the tension of the rope is lower than with a hook of the lifting device with its reinforcement, and when the rope is under tension equal to or greater than the tension when the hook with reinforcement hangs on the rope, the above signal was proportional to the tension of the rope. At the same time, the rotational speed of the motor crust is measured, the received signal is differentiated and summed with the received / 1 earlier signal, forming a signal proportional to the total motor torque as a signal inversely proportional to the full torque of the motor, limiting the task to the maximum allowable frequency of rotation of the motor. The motor speed reference signal is compared to a signal proportional to the rotation frequency of the motor, and the maximum is limited. The value obtained is the difference in the function of the signals of positive feedback on the excitation current and negative feedback modulo the voltage on the core, and the resulting signal is compared with the signal proportional to the current of the core, and is used as a signal for setting the voltage on the electric motor. In addition, a signal proportional to the current of the electric motor core is limited at the upper and lower levels and is used as a signal for setting the excitation current of the electric motor. This method can be implemented in a device whose scheme is shown in the drawing. The armature circuit contains measles 1 electromotor, which is connected to the core 3 of the generator in series with the sensor input 2 of the current of the core, the excitation winding 4 of which is connected to the output of the valve exciter 5 of the generator. Anchor 3 of the generator is on the same shaft with the prime mover. The output of current corr 2 is connected to an input of current corr 6, and in series with a nonlinearity block 7 having a dead zone, a current current regulator 8 to the input of a valve exciter 9, to the output of which in series with the input of an excitation current sensor 10 an excitation coil 11 is connected electric motor. The output of the current regulator 6, the core, is connected to the input of the driver 5, and the input of the current regulator, the core, is connected to the output of the speed regulator 12 and to one of the AC inputs of the limiting unit 13, the second AC output of which is connected to the first input of the regulator 12 rotational speeds, and the DC outputs of limiting unit 13 are oppositely connected to the output of adder 14, the first input of which is connected in series with nonlinearity block 15 having a dead zone, to the output of excitation current sensor 10, and The input of the adder 14 is connected in series with the selector module 16 to the output of the voltage sensor 17, the input. which is connected in parallel to the koryu 1 electric motor. The second input of frequency regulator 12 is connected with one of the AC inputs of the limiting unit 18 to the output of the proportional amplifier 19, to the first input of which the output of the speed setting unit 20 is connected, and the second AC input of the unit 18 is connected to the second input of the amplifier 19 restrictions. The DC output of the limiting unit 18 is connected in opposite to the output of the nonlinearity unit 21 with a hyperbolic characteristic, to the input of which the adder 22 is connected and the zener diode 23, the anode of which is connected to one of the inputs of the adder 22 ,. The output of the direct current of the cable tension sensor 24 (hook weight) directly and through the threshold element 25 is connected to the LRUG inputs of the adder 22. The fourth input of the adder 22 is connected to the output of the differentiation unit 26, the input of which is connected to the rotational speed sensor 27. The device works as follows. With O1; the absence of voltage at the output of the unit 20 of the task and, therefore, the proportional amplifier 19 and the presence of load on the hook in the event of mechanical brakes in the generator and motor core circuit, the current associated with the acceleration of the motor 1 will flow hoisting load on hook. During acceleration of the motor, a signal appears at the output of the rotational speed sensor 27. This signal causes the appearance of a signal at the output of the speed regulator 12, which, by affecting the input of current regulator 6, causes, in turn, the appearance of such a signal at its output, which, by opening the exciter 5, causes the generator to increase (9) motor circuit. Under the action of a current in the core circuit at the output of sensor 2 of the current of the core, a signal is generated that will provide damping, if necessary, residual magnetization of the generator, as well as an increase in the signal at the output of block 7 the excitation current of the exciter 8, the motor exciter 9 and the increase in the current, the excitation winding 11 and the braking torque of the electric motor, as a result of which the rotational speed of the core 1 will be insignificant If there is a load on the hook of the lifting device and, therefore, a relatively large output signal from the sensor 24 the adder 22 and the nonlinearity unit 21 will have the maximum signal. I When a command signal was applied for lifting a load from the output of the block 20, the -. The tribute at the output of the proportional amplifier 19 appears voltage, which can be at # 8 proportional to the reference or limited by the voltage of the subtime of the limiting unit 18, i.e. the voltage at the output of the block 21 nonlinearity. Under the action of the voltage from the output of the amplifier 19, the voltage at the inputs and outputs of the speed regulator 12, the core current regulator 6 i of the valve exciter 5 changes. The voltage is not the output of the regulator 12, which is the reference to the current of the core circuit, limited by a block, 13 limits, the voltage of the backpressure of which is determined by the signals at the input of the adder 14, formed in accordance with the laws of switching using the nonlinearity block 15 from a signal proportional to the excitation current and removed from the output of the sensor 10 current ozbuzhdeni and extractor 16 modulation voltage which is applied to the input signal from the output voltage of the sensor 17. After the growing moment of the electric motor, due to the increase in the core current and the excitation current exceeds the load moment, the engine will accelerate. The output of the differentiation unit 26 is in accordance with a VITS signal, which will increase the signal at the output of the adder 22 and the input of the non-linearity unit 21. As a result, the signal at the output of the nonlinearity unit 21 will decrease, which will further limit the signal at the output of amplifier 19 AND: the load limit of the primary Motor. As the motor accelerates and the dynamic component of the torque on its shaft decreases, the total load on the primary motor shaft decreases, therefore, the signal at the output of the adder 22 decreases and the signal at the output of the nonlinearity unit 21 increases, which causes a block of the limitation 18, and the signal at the output of amplifier 19 will be determined only by the reference signal. If at the beginning of the acceleration the ropes had a slab, then the signal at the output of the sensor 24 would be zero, and therefore the output of the threshold element 25 would be the maximum signal, which in this mode would limit the signal at the input of the speed regulator 12 at the minimum level and therefore minimal rope wrench after the selection of the slack. Thus, carried out with the help of input (limiting the power of the prime mover under heavy load on the motor shaft, i.e. ensuring that the prime mover operates in the mode with maximum KED, the efficiency of the system as a whole is increased and at the same time such regulation ensures the reduction of cable jerks and blows — when choosing slacks. 1. The method of controlling an autonomous electric drive of direct current of the load-lifting mechanism, which regulates the excitation current of the electric motor in function and the current cor, regulate the reference to the maximum current of the current cor as a function of the excitation current and the voltage amplitude on the electric motor bark, characterized in that, in order to ensure the loadless mechanism to work without a shock, the primary motor operates with the maximum possible efficiency, The tension of the hoisting rope and the diage component of the 8-lever motor, when the tension of the rope is less than the corresponding empty hook, form the maximum signgsh guise as well. at i6tfle tension, greater than or equal to the tension, corresponding to the void of the hook, form this signal proportional to the tension, cyt omit the received signal with the signal proportional to the dynamic component, the motor torque, and inversely proportional to the / 1 signal of the result of summation, the motor speed limit setting is changed. 2. An apparatus for implementing a method for controlling an autonomous electric drive of a direct current of a load-lifting mechanism, comprising a motor speed setting unit, a series of rotational speed controllers with a limitation unit in a feedback circuit and a current regulator with a speed sensor connected to their inputs; The current sensor core in the control system of the generator, which supplies the measles of the electric motor, the causative agent of the electric motor, in the control circuit is expensively connected to the current regulator of the current (for example, and a nonlinear element with a dead zone and a limitation of the output signal by the lower and upper levels, one of which is connected between the current sensor core and the second input of the field current regulator, and the other between the excitation current sensor and the adder, the second input of which The module allocation unit is connected to the voltage sensor on the core, and the output is connected to the control input of the limiting unit in the feedback loop of the rotational speed regulator, characterized in that, in order to ensure unaccented operation of the load-lifting mechanism and when the primary engine operates with the highest possible efficiency, a proportional amplifier with a limitation unit in the feedback circuit, a rope tension sensor, a nonlinearity block with a hyperbolic characteristic, a corona element, an adder, made in the form of an operational amplifier with a zener diode are additionally introduced into it. in the feedback circuit, a differentiation unit of the signal of the frequency sensor of the frequency control, with a proportional amplifier connected between the frequency setting unit and the control unit rum rotation frequency, and to its control input through a series-connected threshold element, an adder and a nonlinear element with a hyperbolic characteristic connecting a rope tension sensor, the output of which and the output of the differentiation unit are connected to the inputs of the adder Information sources,. taken into account during the examination 1. USSR author's certificate 482854, cl. H 02 R 5/06, 1975. 2. Authors certificate of the USSR 568131, cl. H 02 R 5/26, 1977 il O -x-u