SU1188842A1 - Device for reversible brushless excitation of sync machine - Google Patents

Description

The invention relates to electrical engineering, in particular to devices for brushless excitation of synchronous machines.

The purpose of the invention is the improvement of overall dimensions and energy indicators, as well as improving reliability.

In Fig, 1 presents a schematic diagram of the proposed device; figure 2 - load characteristics. ·

To simplify, power supplies for all static circuit elements are not shown. They can be solved by any known methods, for example, using transformers connected by primary windings to the power output of a synchronous machine.

The reverse brushless synchronous excitation device of the synchronous machine 1 contains the first 2 and second 3 rotary thyristor converters, AC inputs connected to the armature winding 4 of the auxiliary alternator 5, and the first combined outputs of opposite polarity directly to one of the terminals of the excitation winding 6 of the synchronous machine, the other the output of the field winding 6 is connected with the second opposite outputs of the first 2 and second 3 rotating thyristor converters, respectively first 7 and second 8 field current sensors.

The first 9 and second 10 additional generators are mounted on the same shaft with synchronous machine 1 and the armature windings 11 and 12 are connected respectively 5 through the first 13 and second 14 of the control pulse generation system with control inputs of the first 2 and second 3 rotating thyristor converters. The first 10 and second 10 additional generators have each first 15 (16) and second 17 (18) field windings offset in space by an angle of 90 degrees. The first 15 and second 17 excitation windings of the first additional generator 9 through the corresponding first 19 and second 20 amplifiers, covered by current feedback, and the first sine 21 and first cosine 22 functional converters are connected to the first output of the switch 23, the second output of which is connected to the first 16 and second 18 excitation windings of the second additional generator 10, respectively, through the second sine 24 and second cosine 25 functional converters, as well as the third 26 and fourth 27 amplifiers 30, covered by atnoy link current. The first and second control inputs of the switch 23 are connected to the outputs of the first 7 and second 8 field current sensors, and the information input is connected to the output 3 of the automatic control controller 28 of the field circuit 3, 1188842, the first control inputs connected to the outputs of the voltage sensors 29 and current 30 of the synchronous machine 1 , and the second unitary enterprise; the inputs with the first 7 and second 8 excitation current sensors of the synchronous machine 1. The device also contains a fifth amplifier 31, covered by current feedback, connected to the output windings 32 of the excitation windings of the auxiliary alternator 5, the first 33 and second 34 magnetic field sensors integrated respectively in the field windings of the first 9 and second 10 additional generators, the first 35 and second 36 controlled keys included in the communication points between the first and second outputs of the switch 23 2 (and, respectively, the inputs the first 21 and 22 second 24 and 25 functional 'converters. The control inputs of the first 35 and second 36 controlled keys are connected respectively to 2ί outputs of the second 34 and first 33 of the magnetic field sensors. A controllable switch 37 of the signal polarity and connected to its nonlinear output voltage divider 38, the first and second outputs which are respectively connected to data input switch 23 and the input of the fifth amplifier 31, and the data input of controlled switch 37 with polarity ³⁵ I drove connected to the output of automatic excitation regulator 28 and its control inputs - outputs from the first 7 and second 8 excitation current sensor of the synchronous machine 1, for example, via the sixth 39 and seventh 40 amps.

The controlled signal polarity switch 37 may comprise a command element 4-1 and a switching element 42.

F '

The device operates as follows.

For concreteness, when describing the operation of the device, we accept a synchronous machine 1 — a synchronous compensator, which corresponds to the most difficult conditions of the excitation system, which require equivalent operation of the system at different polarity of currents. excitation in the excitation winding 6.

In the mode of reactive power output, we assume that the first rotating thyristor converter is operating

2.

In this case, depending on the signals from the voltage and current sensors 29 and 30 of the synchronous machine 1, the automatic excitation controller 28 provides a control signal, part of which is supplied through the non-linear voltage divider 38 to the information input of the switch 23. In this case, the excitation current sensor 7 is activated, which the sixth amplifier 39 acts on the first control input of the switch 23 and at the same time, passes the signal from the output of the automatic excitation controller 28 (through a nonlinear divider, 38 voltage) to the inputs of the first sine 21 th and the first cosine. 22 functional converters, the output signals of which are amplified by the first 19 and second 20 amplifiers and enter the first 15 and second 17 excitation windings of the first additional generator 9, shifted in space by an angle of 90 degrees, and creating a magnetic field in the gap with an amplitude proportional to the sum of the squares of the sine and cosine of the same magnitude, i.e. constant regardless of the magnitude of the control signal. The angle in space of the resulting magnetic field vector, determined by the sine and cosine of the signal from the first output of the nonlinear voltage divider 38, is proportional to this signal. Accordingly, the time angle of the electromotive forces (EMF) induced in the armature windings 11 of the first additional generator 9 also turns out to be proportional to the signal from the first output of the nonlinear voltage divider 38 · (the signal from the output of the automatic excitation controller 28). With a constant time EMF in the armature winding 4 of the auxiliary alternator 5, the EMF of the armature winding 11 of the first additional generator 9 through the first control pulse generation system 13 acts on the control circuit of the first rotating thyristor converter 2 with the corresponding control angle, which determines the magnitude of the current in the winding 6 excitation synchronous machine 1. Such processes would be characteristic at constant current in the excitation winding 32 of the auxiliary alternator 5 . In fact, the signal from the second output of the nonlinear voltage divider 38, through the fifth amplifier 31, changes the current in the excitation winding 32. In the embodiment of the excitation winding 32 shown in FIG. 1, this change does not affect the spatial position of the excitation magnetic field of the auxiliary alternating field generator 5 and the temporary position of the EMF in its armature windings and, therefore, the control angle of the first rotating thyristor converter 2, but it does the amplitude of the ZDS auxiliary generator 5 alternating current. Accordingly, the current of the field winding 6 of the Synchronous Machine 1 will be determined not only by the angle of regulation, but also by the amplitude of the EMF of the auxiliary alternator 5.

With the help of the nonlinear divider 38 (selection of its elements), the characteristics that are configured! the device in the considered mode of operation have the form shown in FIG. 2, where · I is the current in the excitation winding 6 of the synchronous machine; ί is the current in the excitation winding 32 of the auxiliary alternator 5. Curve ΐ ₁ corresponds to the diode mode of operation of the first rotating thyristor converter 2 when it is fully open in the entire control range. Curve ί ₂ corresponds to the considered operating mode. As can be seen from FIG. 2, with 1 = 1n - the rated excitation current of the synchronous machine, the rated excitation current of the auxiliary alternating generator 5 is ϊ _n = = 7 ^g D ^e K-, ^{7 1} , Z-Ηή is the nominal excitation current of the diode analog of the rotating thyristor converter. In this case, K _{1 is} significantly less than the generally accepted force factor K = 2, namely K _l E [1,1; 1.32. Therefore, in the nominal operating mode, the auxiliary alternator 5 will be slightly overexcited in comparison with the diode analog. At the same time, magnetic losses, efficiency, overheating, etc. will be in the auxiliary alternator 5 at the level of the diode analog, i.e. the minimum possible .. When K ,, = 1.1 corresponds to the accepted safety factor for diode pathogens, the dimensions of the auxiliary alternator 5 will not differ from the diode analog.

When the signal is forced from the automatic excitation controller 28, the keys of the first rotating thyristor converter 2 are fully opened along the circuit: 28-37-3823-35- (21.22) - (19.20) - (15.17) 11-13-2 and, at the same time, forcing an auxiliary alternator 5 through channel 28-37-38-31-32.

To the point of intersection of the curves ί and C (figure 2), the forcing process proceeds along the curve ί ₂ , and then along the curve to the specified value.

Regulation in the other direction in this mode of operation is carried out through the same control channels, with 1 = 0, ΐ _β Ψ 0 (figure 2). To accelerate the process of damping the field, ΐ ₀ is chosen so that the voltage of the armature windings 4 of the auxiliary alternator 5 is equal to the boost voltage.

The blanking mode of the field during operation of the first rotating thyristor converter 2 proceeds as follows.

In accordance with the new situation in the power system, the automatic controller 28 changes the output signal to. opposite (negative).

The nonlinear divider 38 voltage distributes it in this way,. that the fifth amplifier 31 puts the excitation winding 32 in the operating mode with ΐ ₀ (Fig. 2), and the signal from the first output of the nonlinear divider 38 puts the first rotating thyristor converter 2 into the inverter mode. As a result, the field is suppressed in the excitation winding 6 of the synchronous machine 1, which is fixed using the current measuring circuit 6-7-39. The signal through this channel is supplied to the first control input of the switch 23. With a zero current signal, invert the first rotating thyristor converter. 2 is completed, but the magnetic field due to the current of the damper circuits of the rotor of the synchronous machine 1 has not yet gone out.

To completely extinguish it, a negative current is required in the excitation winding 6 of the synchronous machine 1. If, at zero current signal, the signal from the automatic excitation controller 28 5 remains negative, then the switch 23 switches the signal from its first output to the second. The removal of the signal from the first managed key 35 is accompanied by the transfer of the House of the first 19 and second 20 amplifiers to inverter mode, i.e. damping the field in the first 15 and second 17 field windings of the first additional generator 9 and removing 5 control pulses from the first rotating thyristor converter 2. The second controlled key 36 is ready for operation, but it is blocked by a signal at its control input 20 from the output of the first sensor 33 magnetic field until the magnetic field is almost gone. This eliminates the supply of control pulses to the second rotating thyristor converter 3, until the control pulses from the first rotating thyristor converter 2 are removed, which increases the reliability of the system.

Until the lock is removed from the second managed key 36, the signals from the first sensor 7 (through the sixth amplifier 39). and from the output of the automatic excitation controller 28, the action of a controlled signal polarity switch 37 is triggered, which changes the signals at the input of the nonlinear voltage divider 38.

From the output of the latter through the switch 23 and the second controlled key 36, the second rotating thyristor converter 3 · is fully opened and, simultaneously, through the fifth amplifier 31, the current is boosted in the excitation winding 32 of the auxiliary alternator 5. to a value of 1ph (Fig. 2).

This mode of operation is implemented only when the lock is released from the second managed key 36.

Other modes of operation in the device are carried out in a similar way.

Thus, the present invention allows for ease of execution and high reliability to provide good energy and weight and size indicators.

Claims (1)

(5.7) DEVICE FOR REVERSE BRUSHLESS-FREE BRITTLE EXCITATION OF A SYNCHRONOUS MACHINE, containing first and second rotating thyristor converters, AC inputs connected to the armature winding of an auxiliary alternator, and the first combined outputs of opposite polarity - directly to one of the terminals of the excitation winding of another synchronous machine the field winding is connected to the second opposite outputs of the first and second rotating thyristor converters, respectively, through first and second field current sensors, first and second additional generators mounted on the same shaft with a synchronous machine and anchor windings and connected respectively through the first and second control pulse generation systems with controlled inputs of the first and second rotating thyristor converters, the first and second additional generators have each first and second field windings offset in space by an angle of 90 electrical degrees, the first and second field windings of the first additional the generator through the corresponding first and second amplifiers, covered by current feedback, and the first sine and first cosine functional converters are connected to the first output of the switch, the second output of which is connected to the first and second excitation windings of the second additional generator, respectively, through the second sine and second cosine functional converters, as well as the third and fourth amplifiers, covered by current feedback, the first and second control inputs of the switch are connected to the output and accordingly, the first and second field current sensors, and the information input - with the output of the automatic field controller, the first control inputs associated with the outputs of the voltage and current sensors of the synchronous machine, and the second control inputs with the first and second sensors of the field current of the synchronous machine, characterized in that , in order to improve weight and size and energy indicators, as well as increase reliability, a fifth amplifier is additionally introduced into it, covered by current feedback, output sub connected to the excitation windings of the auxiliary alternating current generator, the first and second magnetic field sensors integrated respectively in the excitation windings of the first and second additional generators, the first and second controlled keys included in the communication places between the first and second outputs of the switch and, respectively, the inputs of the first and second functional transducers, the control inputs of the first and second controlled keys are connected respectively to the outputs of the second and first magnetic field sensors, • except oh, a controlled signal polarity switch is introduced and a nonlinear voltage divider connected to its output, the first and second outputs of which are connected respectively to the information input of the switch and the input of the fifth amplifier, while the information input of the controlled signal polarity switch is connected by the high end of the automatic regulation of excitation, and its control with the outputs of the first and second sensors of the excitation current of the synchronous machine.