SU1206909A1 - Thyratron motor - Google Patents

Description

The invention relates to the field. electrical engineering and can be used in control systems of industrial electric drives with a valve electric motor for various technological mechanisms: compressors, j fans, pumps, mining and metallurgical industries.

The purpose of the invention is to increase the speed of the expansion of the functionality of the valve motor in the regulation of reactive power and simplify the design

The imp is a block diagram {Devices.

The proposed scheme contains a synchronous motor 1, rectifier 2, inverter 3, consumers 4

Energia sensor 5 of reactive engine dm, current sensor 6, pulse phase control system 7 (SLFU) 7 rectifier 5 current regulator 8, control speed rrr 9, speed reference source 10, synchronous speed sensor 1 t motor 1., system 12 pulse-phase control (SIFU) of the inverter, source 13 setting the inverter advance angle, unit 14 generating the departure signal, position sensor rotor 15j sensor 16 reactive power of the power system, first adder 17, first multiplier unit 18, scale Hvr unit 19, second sum ator 20, quad Rhatore 21, non-linear block 22 izvle- chen-I. the square root, the second multi-block 23, the non-linear block 24 with the dead zone and the current, the closing contacts 25 and 26, the speed relay 27, 1 generator 28 square impulses. Blocks 5.16, G /, 18,19,20,21,22,23 and 24 functionally form a unit for adjusting the reactive power of the engine.

The device works as follows.

The synchronous motor 1 is powered by expulsion l-pin 2 and the inverter 3 is powered by a power supply from consumers of electric power 4. The control is carried out in line 2 of the valve motor. The control is carried out by means of a subordinate control system including a pulse-phase control system 7 (SIFU) current regulator 8 and speed regulator 9 connected in series. Pa first regulator input 9

ten

15

thirty

thirty

-

206909I

speed receives the reference signal from the speed reference source 10, and the second input is connected to the sensor 11 of the Brau.e1-ha frequency of the synchronous motor 1. The inverter 3 of the valve motor is controlled by the system 12 of the pulse-phase control, the first input of which through the formation unit 14 the control signal is connected to the output of the source 13 of setting the angle of advance of the inverter. Unit 14 is an amplifier with an input filter. The filter time constant is approximately equal to a quarter of the mains voltage period. The signal from block 13 is taken sufficient to set a control advance angle that provides stable inversion. The power system’s reactive power sensor 16 measures the total reactive power consumed by the valve motor and energy consumers 4. Speed relay 27 — an electronic or mechanical relay — has two levels of operation: up to engine speed less than 0.8-0.9 rated contact 25 is closed; at a higher rotational speed, contact 25 opens. When the engine is completely stopped, using the closing contact 26 of the relay 27, a voltage is applied to the input of the generator 28 of rectangular pulses.

The output voltage of the generator 28 square-wave pulses (with a frequency of about 1000 Hz) is fed directly to the puller distributor SIFU 12 of the inverter, with the result that when the motor is completely stopped, all six thyristors are opened.

40

Blocks 18 and 19, adder 20, quad 21, and block 22 implement the following functional relationship. Full power consumed by the engine

. Q

Where

2

engine power is active;

its reactive power in the absence of regulation. If the reactive power of the engine is adjusted, its value will increase by the value of Q, and the total power is determined

J

s; ip + (Q, + Q,) (1)

Total power increment square

LZ (S; f-s; Qj-2Q, -Q. Increment of the total power

uS. (2)

The sign of the increment of the total power must correspond to the sign of the increment Q ,,. The increment and S correspond to the increment of the current of the rectifier and inverter.

m ------ K- | Q + 2p7o7. (s)

46 U,

As follows from dependency (3) and drawing, blocks 18 and 19, adder 20 and quad 21, blocks 22 and 23 realize a current gain & Ii in the valve motor system. The first adder 17 determines the difference between the actual reactive power of the network and the set

Q. Qn - Q

ChAZ

So, if the power system parameters, such as voltage level, are within the limits allowed by GOST, then the output voltage 1 of the first adder 17 is equal to some small value, since the reactive power is within the specified one. If the voltage in the system becomes less than the set value, which corresponds to the reactive power higher than the set value, then the signal from the first adder 17 will be greater than zero.

The correction signal to the engine management system is received only when the output signal of the first adder 17 exceeds the level specified by the dead zone of the nonlinear block 24 with the dead zone and saturation.

If the signal from the output of the first adder 17 exceeds the permissible level corresponding to the permissible deviations of reactive power, then the output of the nonlinear unit 24 with the dead zone and saturation is positive or negative, and the output of the second multiplier unit 23 produces

06909

the value of the increment g S with -nak corresponding to the sign Q.

 If, for example, Q is positive, then L S must be negative,

5, in this case, it is necessary to increase the control angle of the sensor 2 and increase the control angle of the inverter 3 (decrease the inverter advance angle). At the same time, at the first input of the controller 8

10 current receives a negative signal, to the input of the controller of the block 14 is positive; The emf of the mitel will decrease, the emf of the inverter will increase. A change in the emf of the mittel and the inverter occurs in accordance with the supply voltage of the respective transducers. It is characteristic that it is impossible to change the current value of the EMF in the interval between the two control pulses. In the specified interval, the emf is equal to the instantaneous value (mains supply voltage for mittel and electromotive voltage of the motor for the inverter). Therefore, at a low frequency

25 rotation of the EMF of the inverter 3 changes slowly, and the decrease in the reactive power of the valve engine mainly occurs due to a decrease in the current Ij caused by a decrease in the voltage of the rectifier 2. A certain decrease in the rotation frequency leads to an increase in the signal fed to the second input of the current regulator 8 rectifier 2 from the output of the regulator 9. The voltage on rectifier 2 with a tempo depending mainly on the mechanical time constant of the drive begins to increase. The current remains unchanged, since during this time the control angle of the inverter 3 is set

40

news at a given level.

At frequencies of engine rotation close to nominal, the effect of reducing reactive power can lead to uncontrollability of the valve engine over the contour of the rotational frequency (the angle of control of the angle can not be less than zero). Therefore, at high rotational frequencies, the reactive power control channel along the circuit of block 23 — the rectifier current regulator is resolved by contact 25. Under the conditions of the analyzed case, the appearance of the signal from the second multiplier block 23 leads to a decrease in the control angle of the inverter and a decrease in the current Ij. The equilibrium of the system is restored using speed feedback (from the output of the rotational speed sensor 11 to the input of the regulator 9).

If the network voltage is higher than the rated voltage (the reactive power is less than the rated power), then the correction signal from the output of the multiplying unit 23 will be positive, which corresponds to an increase in the control angle of the rectifier 2 and an increase in the advance angle of the inverter 3.

At low rotational frequency due to the delay of the inverter, the reactive power increases due to an increase in the current Ij when controlling the drive 2. After the control angles of control of the inverter 3 are established, the voltage of the rectifier 2 will decrease due to the tachometer action. The equilibrium of the system occurs at NEW values of the angles of the advance of the inverter control ,.

With a stationary engine, the control of reactive power through the channel of the inverter is impossible, since its EMF is zero. The generator 28 rectangular pulses is triggered when contact 26 is closed. When pulses appear at the output of the generator, 28 rectangular pulses are open

the SIFU 12 limiter to all thyristors of the inverter 3 receives control pulses with a frequency six times lower than the frequency at the output of the generator 28. The inverter valves are all on. Since the contact 25 of the relay 27 when the engine is stationary is closed, the reactive power in the network is regulated only by the control channel of the actuator in the order considered. The current Ij passes through the top of the inverter and inverter, the mine of the stator winding of the motor.

The operation of the system in the event that the engine is operating in a generator mode is similar to that considered.

The positive effect of the application of the invention is due to the fact that regardless of the engine rotational speed, the inertia of the rotating elements of the drive and the working machine, the response speed of the reactive power control loop is at a high level and is limited only by the speed of the converter at the mains supply frequency. In addition, the device can be used as a regulator of reactive power when the engine is completely stopped.

0

five

with esi

- J -J

CI

VNII1SH Order 8730/56 Circulation Circuit Subsidiary Filial PPP Patent, g.Uzhgorod, ul.Proektna, 4

Claims (1)

1. VALVE ELECTRIC MOTOR containing a synchronous machine connected to the supply circuit through a frequency converter with current inverter, a system of pulse-phase control of a rectifier and an inverter of a frequency converter, speed sensors, motor position and current, system, speed control, containing current regulators, rotational speed, frequency governor, reactive power control unit, the output of which is connected to the input of the inverter control system, characterized in that, in order to increase I have the speed and expansion of the functionality of the valve engine in the regulation of reactive power, it is additionally equipped with a generator of rectangular pulses, a rotation speed relay, the output of the control unit for reactive power is connected through the disconnecting contact of the speed relay with the input of the current regulator, the input of the system of pulsed-phase control of the inverter through the closing contact of the relay for the rotational speed of the motor is connected to the output of the rectangular pulse generator. τ'2. An electric motor according to claim 1, considering that, for the purpose of simplification, the reactive power control unit contains sensors of the engine reactive power and network reactive power, the first and second adders, the first and second multiplying blocks, quad, scale block, nonlinearity with the zone insensitivity and limitation, nonlinear square root extraction block, the output of the engine reactive power sensor is connected to the "first input of the first multiplying unit, the network's reactive power sensor is connected to the input of the first sum- The first output of the first adder is connected to the first input of the second adder via the first multiplier unit and the large-scale block; the second output of the first adder is connected to the second input of the second multiplier block via the quad input to the second input of the second adder the third output of the first adder through nonlinearity with the dead zone and the restriction is connected with the second input of the multiplying unit. £ about 35 ABOUT &