SU1757073A1 - Method of starting synchronous machine - Google Patents

Abstract

Use: implementation of the start-up of gas-turbine installations, turbogenerators of synchronous compensators. SUMMARY OF THE INVENTION: Interrogation impulses are applied to the phase pairs of the winding of the core by alternately switching on the corresponding groups of frequency converter gates, and the emf induced in the inductor winding is measured. At each interrogation pulse, the valve group of the frequency converter is determined, which must be turned on first to create the maximum starting torque, the amplitude of the current interrogation pulses in the phases of the winding core, the magnitude of which is controlled by the groups of converter valves, is measured, and after the control of all valve groups This valve group is turned on. 2 Il. with C

Description

The invention relates to electrical engineering, and more specifically to methods for starting synchronous machines, and can be used for starting gas turbines, turbine generators, synchronous compensators, etc.

A known method of starting a synchronous machine is to connect the winding of the core of a synchronous machine to a frequency converter controlled from a rotor position sensor. However, it is not always possible to install the rotor position sensor on the machine in operation.

The closest in technical terms to the invention is a method for starting a synchronous machine with a multi-phase winding of a core connected to a frequency converter and with a single-phase winding.

the inductor, in which current pulse pulses are alternately applied to the phase pairs of the core winding by alternately turning on the respective groups of frequency converter gates, the emf induced in the inductor winding during each interrogation pulse is measured, the group of frequency converter gates is determined, which must be turned on first to create the maximum starting moment, followed by its inclusion.

With a fully functional frequency converter, this method ensures that the synchronous machine starts in a strictly specified direction. However, if the controllability of at least one of the valves of the frequency converter is impaired, the start-up may be accompanied by fluctuations in the rotational speed, change in direction

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rotation and toga turns out to be unsuccessful. These reduces reliability.

The purpose of the invention is to increase the reliability of starting synchronous machines by eliminating fluctuations in the rotation frequency and changing the direction of rotation.

The goal is achieved by starting a synchronous machine with a multiphase core winding connected to a frequency converter and a single-phase inductor winding, according to a method in which interrogation current pulses are alternately applied to pairs of phase windings of the core by alternately turning on the corresponding groups of converter gates frequency, measure the emf induced in the inductor winding at each interrogation pulse, determine the group of valves of the frequency converter, which must be turned on first to create the maximum With each interrogation pulse, the amplitude of the current in the phases of the winding of the core, according to the magnitude of which is judged on the controllability of the converter valve groups, and after establishing the controllability of all the groups of valves, .

Fig, 1 shows a functional diagram of the device that implements the proposed start method; Fig, 2 timing charts of his work.

The synchronous machine contains the core winding 1 and the winding 2 of the inductor. The armature winding is connected to a frequency converter consisting of controlled rectifier 3, a smoothing reactor in DC link 4 and dependent inverter 5. A controlled exciter b and voltage sensor 7 are connected to coil 2 of the inductor. System 8 pulse-phase control the controlled rectifier 3 generates a control pulse for the yentile controlled rectifier 3, and the system 9 of the pulse-phase control of the dependent inverter 5 generates the control pulses for the valves of the dependent inverter 5, the sync voltage control systems come from sensors 10 and 11 of synchronization voltages, respectively, of the rectifier and inverter. The rectified current in the DC link is maintained by the current regulator 12, the input of which receives the current imbalance signal from the output of the adder 13. Feedback signal the current is fed to the input of the adder 13 of the rectified current rectifier; current task Generates the speed controller 15, to which the velocity imbalance signal arrives from the output of the adder 16. The feedback signal on the speed arrives one and inputs of the adder 16 pay-offs 17 speed. On the other input of the accumulator 16 receives the signal speed. A current reference signal is generated by a speed controller 15 with a limit at the level corresponding to the rated current of the frequency converter.

0 Controlled rectifier 3 can operate in the control mode of the rectified current or in the limit inverter mode, the transition to which is produced by a signal produced by the logic

5 by the element 18, which implements the logical function I. The first input of the logical element 18 And receives the signal Acceleration, the second - the signal from the output of the generator 19, which generates at the time of formation

0 current interrogation pulses signals to transfer the controlled rectifier 3 from the inverter mode to the rectified current control mode. The generator 19 has two start inputs, united according to the logic OR scheme, the first of which is given a Start signal, and the second is the End polling signal. The output of the generator 19 is also connected to the input of the generator 20 of the strobe pulse. The first input of the comparator 21

0 is connected to the output of the excitation voltage sensor 7, and the second to the output of the setting unit 22 of the threshold voltage Uo. The direct output of the comparator 21 is connected to the first S input of the R S trigger 23, the second S - input

5 trigger 23 is connected to the output of the generator 20. The inverse output of the comparator 21 is connected to the first S input of the RS flip-flop 24. The second S - input of the trigger 24 is connected to the output of the generator 20, and the third to the output

0 trigger 23. The output of the trigger 24 is connected to the second input of the generator 19, as well as to the exit End of the survey. The outputs of the sensor 25 current and the AC circuit dependent inverter 5 is connected to the first inputs

5 six comparators 26, the second inputs of which are connected to the outputs of the setpoint adjuster 27 of the current setting 10. The outputs of the comparators 26 are connected to the information inputs of the register 28, the zeroing input

0 which is connected to the Start input. The outputs of the register 28 are connected to the inputs of the six-input logic element 29, which implements the logical function OR. The output of the logic element 29 OR is connected to the inverse R inputs of the flip-flops 23 and 24.

The device works as follows.

In the initial state, the Start and Overclocking signals are equal to logic 1 (see Fig. 2, curves 1.13), the excitation current is zero. Then, at the outputs of the generator 19 and the logic element 18 AND (see FIG. 2, curve 7), the signals are equal to logical 1, and the controlled rectifier 3 operates in the inverter mode. The currents in the DC link 4 and in the AC output circuit of the dependent inverter 5 are missing (see Fig. 2, curves 4,5,6). Register 28 is reset, so at the output of logic element 29 And the signal is equal to logical 0 (see Fig. 2, curve 8), triggers 23 and 24 are also zero (see Fig. 2, curves 11.12).

When an Start command is received from the outside (see FIG. 2, curve 1), the nulling signal is removed from the zero-reset input of the register 28, and generator 19 forms a burst (see FIG. 2, curve 2), each of which is a command to transfer the controlled rectifier 3 from the inverter mode to the direct mode of operation. On the front of these pulses, coming from the output of the logic element 18 OR to the input of the estimate 9 of the pulse-phase control of the inverter 5, the corresponding groups of valves of the dependent inverter 5 are alternately turned on. Since the rotor of the synchronous machine is still, the feedback signal on the speed is zero, therefore, the speed controller 15 generates the maximum signal for setting the current, determined by its limit setpoint. Each pulse of the COOT-19 generator corresponds to a pulse of rectified current of trapezoidal shape in DC link 4, current pulses in pairs of phases of the winding of the core of a synchronous machine (see Fig. 2, curves 4.5) and voltage pulses induced in winding inductor (see figure 2, curve 9). The current pulses flowing in the phases of the winding of the synchronous machine core go through the current sensor 25 to the inputs of the comparators 26. Comparators 26 actually measure the interrogation current pulses by comparing their values with the threshold value determined by the setting device 27. The alternating occurrence of the inputs of all comparators 26 signals exceeding the threshold value indicate the presence of all the gates of the inverse inverter 5 in the control mode. If there is conductivity in all the gates of the dependent inverter 5 for five interrogation pulses in all six bits of register 28 signals are logic 1, and the output of coincidence gate 19 to a logic 1 signal Vits (see FIG. 2, curve 8) will be recorded. The nulling signal from the R-inputs of the trigger 23,24 is removed / and these Triggers have the ability to perceive

through the S inputs of the signals of the comparator 21, the Comparator 21 fixes the polarity of the voltage pulses induced in the winding of the inductor 2 (see Fig. 2, curves 9,10). The generator 20 forms a packet strobe pulses (see figure 2, curve 3). The trigger 23 is switched when a voltage pulse interval appears on a fixed generator 20 that exceeds the threshold voltage of the comparator 21 defined by the voltage setter 22. The trigger 24 is switched, if the trigger 23 has already been switched and a voltage pulse appears on the interval fixed by the generator 20 and does not exceed the threshold value of the comparator 21 (see Fig. 2, curves 11,12). Switching the trigger 24 causes the generator 19 to stop working, and a signal to the end of the interrogation is formed (see Fig. 2, curve 12).

This signal instructs the controlled driver 6 to set the desired value of the excitation current. After that, the Overclocking command can be issued (see FIG. 2, Krivai 13).

Thus, the start-up is carried out only if the controllability of all groups of dependent inverter 5 is available. It is this that allows you to get a positive effect and increase the reliability of the synchronous machine start-up. A similar system of controllability can be applied in the controlled rectifier 3,

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Claims (1)

Formula invented shadows Starting method of a synchronous machine with a multiphase core winding connected to a frequency converter and a single phase inductor winding, in which interrogation current pulses are alternately applied to the phase pairs of the core winding by alternately turning on the corresponding groups of frequency converter fans, the EMF induced in the inductor winding is measured at each polling pulse, a group of frequency converter gates is determined, which must be turned on first to create the maximum starting torque, followed by switching on It, in view of the fact that, in order to increase the reliability of the start-up of the machine by eliminating fluctuations in the rotational frequency and changing the direction of rotation during the start-up, the amplitude of the current interrogation pulses in the winding core phases is additionally measured at each interrogation pulse controllability valve groups converters, and after establishing the controllability of all groups The valves turn on the indicated group of valves. Yu cemi