SU1605296A1 - Method and apparatus for controlling mutual load system in testing - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to reduce the test time by reducing the time required to transfer the unit from one steady state to another. The method of controlling the mutual load aggregate consists in the fact that during acceleration or deceleration of the aggregate, respectively, the generator excitation current decreases or increases from the nominal value. In the process of transferring the unit from one steady state to another, the core current is stabilized at a level exceeding the nominal value by changing the source voltage. At the same time, the rotational frequency is measured and, when its average value is reached, equal to the half-sum of the initial and specified rotational speed values, the sign of the derivative of the generator excitation current is changed. When a predetermined rotational speed is reached, the rated value of the power supply voltage is set. A schematic diagram of the device for implementing the method. 3 hp f-ly, 3 ill.

Description

The invention relates to electrical engineering, namely to electric drives of stands dp used under load of electric machines, as well as gearboxes and other rotating elements of mechanical gears.

The purpose of the invention is to shorten the testing time by reducing the time of transfer of the unit from one steady state to another.

Fig. 1 is a schematic diagram of a mutual load unit control unit; Fig. 2 shows graphs of the generator flux, source voltage e, unit current I, and unit speed CO when the unit is transferred from the source

in a given mode according to the proposed method; FIG. 3 is a schematic diagram of the nporpaNMHoro block.

A device that implements the method of controlling the mutual load aggregate contains a motor and a generator 2, the main circuits of which are connected in series with each other and with the source 3 through the current sensor 4 of Korea, and the shafts of the engine 1 and generator 2 are connected with each other and with the speed sensor 5, - this excitation winding of the engine 1 is connected to the source 6, and the excitation winding of the generator 2 through the sensor 7 of the excitation current is connected to the controller 8.

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about:

The input of the regulator 8 is connected to the switching contact of the first nepeioiK) —chapter 9, controlled by the threshold element 10, the input of which is connected to the output of the first comparing element 11 to the fixed contact of the first switch 9. The other fixed contact of the first switch 9 is connected to the second contact switch a switch 12 controlled by the first comparator 13. The fixed contacts of the second switch 12. connected to bipolar outputs of a source that sets the maximum positive and negative excitation currents of the generator 8; the first input of the pernog. comparator 13 is connected to the output of the speed sensor 5 and the input of the second comparator 14, which controls the third switch 15, the switching contact of which is connected to the input source 3. One fixed contact of the third switch 15 is connected to the output of the second comparing element 16, the input of which is connected to the current sensor 4 of Korea, and the second inputs of the second comparing element 16 5 of the first comparing element 11, the comparators 13 and 14 and the second fixed contact of the third switch 15 are connected to the outputs of the program block 17.

The program block 1 7 sets at its outputs signals determining the levels of the maximum allowable current, voltage of source 3, generator excitation current 2, angular velocity at which generator excitation 2 switches and the set speed of the unit.

Program block 17 contains a clock pulse generator 18, a pulse distributor 19, keys 20-22, potentiometers 23-27,

The output of the generator 18 clock pulses are connected to the input of the distributor 19 pulses 5 whose outputs are connected to their control inputs 1 keys 20-22, Keys 20-22 connected to the middle points their potentiometers 23-27, and the outputs of keys 20-22 are combined and are the outputs of block 17,

The clock pulses of the generator 18 are converted into signals at the corresponding outputs of the distributor 19, which connect the pre-programmed points of the potentiometers 23-27 to the outputs of the program block 17 with the help of their keys 20-22.

The device works as follows.

The software block 17 sets at its outputs signals specifying the values of the maximum permissible current 1 dop "source voltage e., 3, excitation current (flow (rz) of generator 2, switching speed CO" excitation of generator 2 and given set speed 03 of the unit. The signals are pre-set and sequentially switched by the program block 17 in accordance with the test program on the unit. In the initial state, the switches 16 and 9 are in the right position according to the diagram (Fig. 2), which provides the excitation current specified by block 17 torus 2 due to the effect of negative feedback, carried out by the current sensor 7 and the first comparing element 11, and the set value of the voltage BJ of the source 3, which is determined by the signal of the block 17 to the right, the contact of the third switch 15,

The speed of the unit corresponds to a given COj at the output of block 17 connected to the input of the second comparator 14.

After the program block 17 establishes new values of the set signals, the second comparator 14 compares the set signal with the signal of the speed sensor 5 and switches the contact of the third switch 15 to the left position. The source 3 will maintain the maximum permissible current of 1 korea given by block 17 due to the negative feedback provided by the sensor 4 and the second comparing element 16. The first comparator 13 switches the contact of the second switch 12 to the right position if the switching speed specified by block 17 , more than the speed of the unit, controlled by sensor 5 (if the speed of the unit is greater than the specified switching speed, the first comparator 13 will switch the second switch 12 to the left position).

The first switch 9 is set to the left position, since iTopo.roi element 10 responds to the occurrence of a large mismatch at the output of the first comparator

5 .16

element 1) between the signals of the current sensor 7 and the note given by the block 17 signal at the output of the first comparing element 1I.

At the output of the regulator 8, a maximum negative signal appears, which provides the highest rate of decay of the excitation current — generator 2, the unit accelerates with the highest possible speed.

When the speed value exceeds the switching speed set by block 17, the first comparator 13 switches off, the second switch 12 goes to the left position and the excitation current starts to increase at the highest speed determined by the maximum signal at the output of the regulator 8. When the current (flow) is reached excitation equal to 3-given F3; threshold element 10 switches the first switch 9 to the right position and provides the required excitation current. When the speed reaches the preset value 9g, the second comparator 14 switches the third switch 15 to the right position and provides the preset voltage of source 3. The unit switches to the new preset mode. When establishing

the software unit 17 of the new mode of operation of the device is similar to that described above.

In analyzing the method for simplicity, let us assume that the rate of change of the generator excitation current 3 is constant, which is acceptable when there is enough reserve for the voltage of the generator excitation regulator 8, 1 kg, the maximum voltage of the excitation regulator is much greater than the voltage drop across the excitation winding from excitation current

The moment of switching tj should be chosen in such a way that by the moment of reaching the speed of CO the excitation current will take the required value Isj i.e. so that the required speed and current values are achieved simultaneously. By integrating the equation of motion on the sections before and after the switch, we obtain after the conversion of Sop 0.5 (SOC-+ 0h).

35

Formula

the invention

Neither I.

diB

L

L is the inductance of the generator excitation winding, (в is a constant value:

.

We write the equation of motion of the unit

-f- “,

- M - M

about

where I is the moment of inertia of the unit; M., electromagnetic moments

OTBei stb.nno engine and

nerator;

1. The control method when testing a mutual load unit containing 40 dc machines with a series connection of the machine and a korea source, in which the generator excitation current decreases from the nominal generator and the power 45 rotates the voltage

of the switched on source and the excitation current and thereby establish the specified load mode, characterized in that, in order to reduce the test time by reducing the time for the unit to transfer from one steady state to another, when the generator is braked, its excitation current increases from the nominal value , and at 55 transfer of the unit from one steady state to another stabilize the current korg at a level exceeding the nominal value by changing the voltage of the source, while measuring

soge

6

Mp is the moment determined by the mechanical and power losses in the unit.

We believe that in transient regimes, the maximum Korean tech 1d is maintained, and consequently, the maximum moment MD. We also take M kig, where e k cl, oi;

j r V

coefficient of proportionality between the current and the flow of the generator.

When the unit is accelerated from the speed COj to the rate of CO 3, the excitation current (flow) of the generator IB IBH yt is first reduced, then the acceleration currents corresponding to the onset of acceleration and switching moment, Cx) the speedi at which occur

switching.

The moment of switching tj should be chosen in such a way that by the moment of reaching the speed of CO the excitation current will take the required value Isj i.e. so that the required speed and current values are achieved simultaneously. By integrating the equation of motion on the sections before and after the switch, we obtain after the conversion of Sop 0.5 (SOC-+ 0h).

35

Formula

the invention

soge

the frequency of rotation of the unit and when it reaches its value equal to the half sum of the initial and specified values of the rotation frequency change the sign of the derivative of the generator excitation current, and when the specified rotation frequency is reached, the nominal voltage of the source

2 The device is installed during and after testing by the unit of mutual load of direct current machines, which contains the power sources of the main circuits and the excitation windings, intended for dp connection to the main circuits and the excitation windings of the tested machines. ., equipped with regulators, sensors, KOBj, voltage and frequency of rotation of the unit, switching units, characterized in that, with shortening test time, equipped with three switches with two fixed and one moving contact and control circuits, two comparators mi and The primary element, the first control unit and the switches, the source of the setpoint signal of the regulator air, the generator, two comparison elements, the program block with five outputs corresponding to the command and current power supply voltage, rotation frequency, switching frequency and excitation current of the generator; the first output of the program block is connected to the crushing voltage, and the current sensor output is connected to the subtractive inputs of the second comparison element, the output of which is connected to first fixed contact There is a switch, another fixed contact of which is connected to the second output of the nporpar-iMHoro unit, while the control input of the power supply of the main circuits is connected to the mobile contact of the third switch, the control which is connected to the output of the second comparator

 which are connected to the rotational speed sensor and the third output of the program block, the first comparator is connected to the rotational speed sensor and the fourth output of the program block by its inputs, and the output to the control circuit of the second switch, the fixed contacts of which are connected to different source signal terminals the setpoint of the generator control unit, and the switching contact is with the fixed contact of the first switch, another fixed contact of which is connected to the output of the first matching element nta and the input of the threshold element, the output of which is connected to the control circuits of the first switch, whose contact is connected to the input of the generator excitation regulator, while the fifth output of the program block is connected to the summing input of the first comparing element, which subtracts the input connected to the output of the excitation current sensor. generator,

Зе The device according to claim 2, that is, with the fact that the program block is equipped with a clock pulse generator, a pulse distributor with four key elements five potentiometers, and the clock pulse generator and pulse distributor are connected in series, and the outputs of the pulse distributor are connected to the control inputs of the key elements, one outputs of which are connected to the middle points of the second, third, fourth, and fifth potentiometers, and others; are the corresponding. outputs of the program block; the first output of the program block is connected directly to the midpoint of the first potentiometer.

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51

Claims (3)

Claim 1. The control method when testing the mutual load unit containing DC machines with a series connection of the armature of the machines and the source, in which, when the unit is accelerating, the generator excitation current is reduced from the nominal one and the voltage of the series-connected source and the excitation current are regulated L is the inductance of the excitation winding of the generator, ψ is a constant value: I ₆ =. We write the equation of motion of the unit and thereby establish the specified load mode, characterized in that, in order to reduce the test time by reducing the time the unit is transferred from one steady state to another, when the generator is braked, its excitation current increases from the nominal value, and when I aggregate inertia moment; electromagnetic moments responsibly of the engine and the generator; transferring the unit from one steady state to another, stabilize the armature current at a level exceeding the nominal value by changing the voltage of the source, measure the speed of the unit and, when it reaches a value equal to half the initial and specified values of the rotation frequency, change the sign of the derivative of the generator excitation current, and when the specified speed is reached, the rated voltage of the source is set. 2 "The control device when testing the unit mutual load DC machines, containing ¹ power supply of the armature circuits and field windings, designed to connect to the armature circuits and field windings of the tested machines, equipped with regulators, current sensors _s voltage and speed of the unit, switching units, different We note that, in order to reduce test time, it is equipped with three switches with two fixed and one movable contact and control circuits, two comparators and thresholds an element that controls the switches, the signal source of the setpoint of the generator excitation regulator, two comparing elements, a program block with five outputs, respectively, with preset values of the armature current, voltage of the power source, speed, switching frequency and generator excitation current, while the first output of the program unit is connected with summing, and the output of the current sensor with subtracting inputs of the second comparing element, the output of which is connected to the first fixed contact of the third switch ator, the other stationary contact of which is connected to the second output, the software unit, and the control power supply input anchor chains connected to the movable contact of the third pereklyuchi-: of Tell, which sub ^{upravlyayuschie.tsepi:} klyucheky to the output of the second comparator, whose inputs are connected to the sensor speed and the third output of the program unit, the first comparator with its inputs connected to the speed sensor and the fourth output of the program unit, and the output to the control circuits of the second switch, stationary its contacts are connected to bipolar clamps of the signal source of the setpoint of the generator excitation controller, and the switching contact is connected to the fixed contact of the first switch, the other fixed contact of which is connected to the output of the first comparison element and the input of the threshold element, the output of which is connected to the control circuits of the first switch, the contact of which is connected to the input of the generator excitation controller, while the fifth output of the program unit is connected to the summing input of the first estimating translates member, the subtracting input of which is connected to the output of the sensor excitation current. generator. 3. The device according to claim 2 ', characterized in that the program unit is equipped with a clock generator, pulse distributor, four key elements, five potentiometers, while the clock generator and pulse distributor are connected in series, and the output of the pulse distributor is connected to the control inputs of the key elements, some outputs of which are connected to the midpoints of the second, third, fourth and fifth, potentiometers, and other outputs are the corresponding block ·, while the first output of the program block is connected directly to the midpoint of the first potentiometer.