阅读说明：本技术 三相全控整流桥触发脉冲的相序自适应控制系统及方法 (Phase sequence self-adaptive control system and method for three-phase full-control rectifier bridge trigger pulse ) 是由 林元飞 许其品 朱宏超 赵志成 徐春建 季婷婷 郝勇 王亚婧 郑尧山 于 2019-09-25 设计创作，主要内容包括：本发明公开了一种三相全控整流桥可控硅触发脉冲的相序自适应控制系统及方法,包括：测量整流桥三相交流电源的相序,若存在负序并经用户确认后,则根据交流电源相序实时调整励磁系统输出的触发脉冲,从而保证三相全控整流桥的正确输出,无需调整交流电源进线。本发明可以解决调试检修过程中,由于铜排设计错误或人为接线错误导致励磁系统无法正常运行的问题。本发明完善了励磁调节器触发脉冲的控制逻辑,提升了励磁系统的冗余容错能力,通过减少工作量提高了现场调试效率。(The invention discloses a phase sequence self-adaptive control system and method for silicon controlled trigger pulse of a three-phase full-control rectifier bridge, which comprises the following steps: and measuring the phase sequence of the three-phase alternating current power supply of the rectifier bridge, and if a negative sequence exists and is confirmed by a user, adjusting the trigger pulse output by the excitation system in real time according to the phase sequence of the alternating current power supply, so that the correct output of the three-phase fully-controlled rectifier bridge is ensured, and the incoming line of the alternating current power supply is not required to be adjusted. The invention can solve the problem that the excitation system cannot normally operate due to wrong copper bar design or artificial wiring errors in the debugging and overhauling process. The invention improves the control logic of the trigger pulse of the excitation regulator, improves the redundancy fault-tolerant capability of the excitation system, and improves the field debugging efficiency by reducing the workload.)

1. Three-phase full control rectifier bridge trigger pulse's phase sequence adaptive control system, its characterized in that includes:

the synchronous voltage loop is used for sampling a three-phase alternating current synchronous signal, finishing primary amplitude transformation and isolation of voltage, carrying out secondary amplitude transformation of the voltage and converting the three-phase alternating current synchronous signal into a synchronous square wave signal;

the synchronous phase sequence measuring unit is used for judging the positive sequence and the negative sequence of the synchronous phase sequence;

and the silicon controlled trigger pulse control unit is used for generating silicon controlled trigger pulses and realizing selection and switching control of the output silicon controlled trigger pulses through the positive sequence/negative sequence gating switch.

2. The system of claim 1, wherein the synchronous voltage loop is configured to sample a three-phase ac synchronous signal through a three-phase synchronous transformer TBB and perform a first amplitude transformation and isolation of voltage, perform a second amplitude transformation of voltage through a three-phase isolation transformer and an RC filter, perform phase matching and harmonic suppression processing, perform amplitude adjustment of synchronous voltage using an operational amplifier, and convert the three-phase ac synchronous signal into a synchronous square wave signal through a hysteresis comparator.

3. The adaptive control system for the phase sequence of the trigger pulse of the three-phase fully-controlled rectifier bridge according to claim 2, wherein the three-phase synchronous transformer TBB is connected with the output end of the excitation transformer LCB in a Y/. DELTA.11 connection.

4. The system of claim 2, wherein the three-phase isolation transformer is connected to the output of the three-phase synchronous transformer TBB in delta/Y-11.

5. The system according to claim 1, wherein the synchronous phase sequence measuring unit is configured to record a level of a current three-phase synchronous square wave signal according to a rising edge and a falling edge of the synchronous square wave signal to obtain a phase sequence of the synchronous square wave signal;

and judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence.

6. The system of claim 1, wherein the scr trigger control unit is configured to generate a double narrow pulse, a first pulse signal of the double narrow pulse is generated according to a synchronous square wave signal, and a second pulse signal is generated by a pulse post-compensation of a next scr-on pulse.

7. The system according to claim 6, wherein the scr trigger control unit is specifically configured to generate + a-phase and-a-phase scr trigger pulses according to the delay angles of the rising edge and the falling edge of the a-phase synchronous square wave signal if the synchronous phase sequence is a positive sequence; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the B-phase synchronous square wave signals; generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals;

if the synchronous phase sequence is a negative sequence, generating a + A phase silicon controlled trigger pulse and a-A phase silicon controlled trigger pulse according to the delay angle of the rising edge and the falling edge of the B same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals; and generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the A same-step square wave signals.

8. The phase sequence self-adaptive control method of the three-phase full-control rectifier bridge trigger pulse is characterized by comprising the following steps:

sampling a three-phase alternating current synchronous signal;

carrying out primary amplitude transformation and isolation on the three-phase alternating current synchronous signal, and converting the three-phase alternating current synchronous signal into a synchronous square wave signal after carrying out secondary amplitude transformation on the voltage;

obtaining a phase sequence of the synchronous square wave signal according to the rising edge and the falling edge of the synchronous square wave signal;

judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence;

different signals are respectively adopted as synchronous signals according to the positive sequence and the negative sequence of the synchronous phase sequence, and trigger pulses are respectively generated.

9. The phase sequence adaptive control method of the trigger pulse of the three-phase fully-controlled rectifier bridge according to claim 8, wherein the positive-sequence synchronous phase sequence is as follows:

the negative sequence of the synchronous phase sequence is:

judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence, comprising the following steps:

after the rising edge/falling edge of the A same-step square wave signal is detected, the programmable logic chip reads and records A, B the level of the C synchronous signal, and B and C are the same; after one cycle of processing, if the octal sequence number is 563, the synchronous phase sequence of the positive sequence is determined, and if the octal sequence number is 635, the synchronous phase sequence of the negative sequence is determined.

10. The phase sequence adaptive control method of the trigger pulse of the three-phase fully controlled rectifier bridge according to claim 8, wherein the step of respectively generating the trigger pulse by respectively adopting different signals as the synchronous signals according to the positive sequence and the negative sequence of the synchronous phase sequence comprises the following steps:

if the synchronous phase sequence is a positive sequence, generating a + A phase and a-A phase silicon controlled trigger pulse according to the rising edge and falling edge delay angles of the A same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the B-phase synchronous square wave signals; generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals;

if the synchronous phase sequence is a negative sequence, generating a + A phase silicon controlled trigger pulse and a-A phase silicon controlled trigger pulse according to the delay angle of the rising edge and the falling edge of the B same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals; and generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the A same-step square wave signals.

Technical Field

The invention provides a phase sequence self-adaptive control system and method for three-phase full-control rectifier bridge trigger pulses, and belongs to the technical field of excitation control of generators.

Background

A rectifier cabinet consisting of a three-phase fully-controlled rectifier bridge is an important component of a generator excitation system, rectifies an alternating current power supply into direct current, and transmits the direct current to a generator rotor winding to provide a stable magnetic field. As a controllable power supply circuit, trigger pulse control is a core technology part of a three-phase fully-controlled rectifier bridge, and a three-phase synchronous transformer is required to provide a synchronous signal as a reference signal of a trigger angle. For a three-phase alternating current power supply, the phase of positive sequence power supply is 120 degrees after B phase retardation and 120 degrees after C phase retardation. If the access mode of the three-phase incoming line input end of the synchronous transformer is A, B, C or B, C, A or C, A and B, the phase difference of any two adjacent phases is 120 degrees, and the phase difference is a positive phase sequence; if the access mode is three sequences of A, C, B or C, B, A or B, A and C, the phase difference of any two adjacent phases is 240 degrees, and the phase difference is a negative phase sequence. The phase sequence type of the three-phase alternating current power supply can be obtained by measuring and judging the synchronous phase sequence type.

Only when the externally input three-phase alternating current cable or copper bar is connected in a positive sequence, the trigger pulse output by the excitation regulator can be normally conducted and phase-changed corresponding to the controllable silicon of the rectifier cabinet, and the voltage waveform and the numerical value output by the three-phase fully-controlled rectifier bridge are correct. However, when the negative sequence connection occurs due to a wrong copper bar design or a man-made wiring error, the trigger pulse of the excitation regulator still selects the synchronous reference signal according to the positive sequence and generates a pulse to trigger the silicon controlled rectifier, at the moment, the silicon controlled rectifier cannot correctly change the phase, the output rectified waveform also has an angle error, the output of the rectifier bridge is abnormal, and the excitation system cannot normally operate.

Disclosure of Invention

The invention aims to provide a phase sequence self-adaptive control method of three-phase full-control rectifier bridge trigger pulse, which realizes the phase sequence self-adaptive control of the trigger pulse by measuring and judging a synchronous phase sequence, overcomes the constraint of the phase sequence and solves the problem that an excitation system cannot normally operate due to copper bar design errors or manual wiring errors in the debugging and overhauling process.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

phase sequence self-adaptive control system of three-phase full-control rectifier bridge trigger pulse includes:

the synchronous voltage loop is used for sampling a three-phase alternating current synchronous signal, finishing primary amplitude transformation and isolation of voltage, carrying out secondary amplitude transformation of the voltage and converting the three-phase alternating current synchronous signal into a synchronous square wave signal;

the synchronous phase sequence measuring unit is used for judging the positive sequence and the negative sequence of the synchronous phase sequence;

and the silicon controlled trigger pulse control unit is used for generating silicon controlled trigger pulses and realizing selection and switching control of the output silicon controlled trigger pulses through the positive sequence/negative sequence gating switch.

Further, the synchronous voltage loop is specifically used for sampling a three-phase alternating current synchronous signal through a three-phase synchronous transformer TBB, performing primary amplitude transformation and isolation of voltage, performing secondary amplitude transformation, phase matching and harmonic suppression processing of voltage through a three-phase isolation mutual inductor and an RC filter, performing amplitude adjustment of synchronous voltage through an operational amplifier, and converting the three-phase alternating current synchronous signal into a synchronous square wave signal through a hysteresis comparator.

Further, the three-phase synchronous transformer TBB is connected with the output end of the excitation transformer LCB, and the connection method is Y/delta-11.

Further, the three-phase isolation mutual inductor is connected with the output end of the three-phase synchronous transformer TBB, and the connection method is delta/Y-11.

Further, the synchronous phase sequence measuring unit is specifically configured to record the level of the current three-phase synchronous square wave signal according to a rising edge and a falling edge of the synchronous square wave signal, so as to obtain a phase sequence of the synchronous square wave signal;

and judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence.

Further, the thyristor trigger pulse control unit is specifically configured to generate a double narrow pulse, a first pulse signal of the double narrow pulse is generated according to the synchronous square wave signal, and a second pulse signal is generated by supplementing a next pulse for conducting the thyristor.

Further, the thyristor trigger pulse control unit is specifically configured to generate + a-phase and-a-phase thyristor trigger pulses according to the delay angles of the rising edge and the falling edge of the a-phase synchronous square wave signal if the synchronous phase sequence is a positive sequence; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the B-phase synchronous square wave signals; generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals;

if the synchronous phase sequence is a negative sequence, generating a + A phase silicon controlled trigger pulse and a-A phase silicon controlled trigger pulse according to the delay angle of the rising edge and the falling edge of the B same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals; and generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the A same-step square wave signals.

The phase sequence self-adaptive control method of the three-phase full-control rectifier bridge trigger pulse comprises the following steps:

sampling a three-phase alternating current synchronous signal;

carrying out primary amplitude transformation and isolation on the three-phase alternating current synchronous signal, and converting the three-phase alternating current synchronous signal into a synchronous square wave signal after carrying out secondary amplitude transformation on the voltage;

obtaining a phase sequence of the synchronous square wave signal according to the rising edge and the falling edge of the synchronous square wave signal;

judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence;

different signals are respectively adopted as synchronous signals according to the positive sequence and the negative sequence of the synchronous phase sequence, and trigger pulses are respectively generated.

Further, the positive sequence of the synchronous phase sequence is:

the negative sequence of the synchronous phase sequence is:

judging the positive sequence and the negative sequence of the synchronous phase sequence according to the obtained phase sequence, comprising the following steps:

after the rising edge/falling edge of the A same-step square wave signal is detected, the programmable logic chip reads and records A, B the level of the C synchronous signal, and B and C are the same; after one cycle of processing, if the octal sequence number is 563, the synchronous phase sequence of the positive sequence is determined, and if the octal sequence number is 635, the synchronous phase sequence of the negative sequence is determined.

Further, the respectively generating the trigger pulse by using different signals as the synchronous signals according to the positive sequence and the negative sequence of the synchronous phase sequence includes:

if the synchronous phase sequence is a positive sequence, generating a + A phase and a-A phase silicon controlled trigger pulse according to the rising edge and falling edge delay angles of the A same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the B-phase synchronous square wave signals; generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals;

if the synchronous phase sequence is a negative sequence, generating a + A phase silicon controlled trigger pulse and a-A phase silicon controlled trigger pulse according to the delay angle of the rising edge and the falling edge of the B same-step square wave signal; generating + B-phase and-B-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the C-phase synchronous square wave signals; and generating + C-phase and-C-phase silicon controlled trigger pulses according to the rising edge and falling edge delay angles of the A same-step square wave signals.

The invention achieves the following beneficial effects:

the invention can solve the problem that the excitation system cannot normally operate due to wrong copper bar design or artificial wiring errors in the debugging and overhauling process.

The invention improves the control logic of the trigger pulse of the excitation regulator, improves the redundancy fault-tolerant capability of the excitation system, and improves the field debugging efficiency by reducing the workload.

Drawings

Fig. 1 is a schematic diagram of a synchronous phase-sequence adaptive control system according to the present invention.

FIG. 2 is a schematic diagram of synchronous phase sequence detection in the present invention, and FIG. 2(a) is a positive sequence detection; FIG. 2(b) is a negative sequence assay;

FIG. 3 is a flow chart of the present invention for determining the synchronous phase sequence.

FIG. 4 is a phase diagram of the synchronous phase voltage and the synchronous square wave in the negative sequence of the present invention.

Fig. 5 is a pulse sequence diagram of a three-phase fully-controlled rectifier bridge in the invention under positive phase sequence.

Fig. 6 is a pulse sequence diagram of the three-phase fully controlled rectifier bridge in the negative phase sequence.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1, an embodiment of the present invention provides a synchronous phase sequence adaptive control system, which includes an excitation transformer LCB for providing a three-phase ac power supply, where the excitation transformer LCB is connected to a three-phase fully-controlled rectifier bridge FLZ through an ac knife switch.

The output end of the excitation transformer LCB is sequentially connected with a three-phase synchronous transformer TBB, a synchronous voltage detection board, an RC filter, a hysteresis comparator and an excitation regulator. The excitation regulator is a control unit of an excitation system, and adopts deviation closed-loop control according to a given value and an actual measurement value, so that a controlled quantity is maintained at a given level.

Furthermore, the connection method of the three-phase synchronous transformer is Y/delta-11, the synchronous voltage detection plate is a three-phase isolation mutual inductor, and the connection method is delta/Y-11.

The phase sequence adaptive control process of the embodiment of the invention is described by taking synchronous generator excitation rectifier bridge pulse control as an example:

the method comprises the following steps: according to the actual connection method of an AC cable or a copper bar from the secondary side of an excitation transformer LCB to the input side of a three-phase fully-controlled rectifier bridge, a three-phase synchronous transformer TBB samples signals and completes primary amplitude conversion and isolation, voltage secondary amplitude conversion, phase matching and harmonic suppression processing are performed through a three-phase isolation mutual inductor and an RC filter, the accessed synchronous signals containing a large number of harmonic high voltage values are converted into AC signals only containing fundamental wave signals, an operational amplifier is used for adjusting the amplitude of the synchronous voltage, and a hysteresis comparator is combined to convert the AC synchronous signals into square wave signals.

According to the connection method of the three-phase synchronous transformer and the synchronous voltage detection board, under positive sequence wiring, the phase of the three-phase synchronous phase voltage subjected to amplitude conversion twice is advanced by 60 degrees of an electrical angle of an original signal, and the phase characteristic of a fundamental frequency signal of the RC filter lags by 90 degrees. Therefore, the final square wave signal lags behind the corresponding phase voltage by 30 ° in electrical angle, and the rising edge and the falling edge of the synchronous square wave signal are just corresponding to the 0 ° trigger angle (natural commutation point) of each phase pulse.

Step two: the level of the current three-phase synchronous square wave signal is recorded by utilizing the rising edge and the falling edge of the synchronous square wave signal, and the phase sequence of the synchronous square wave signal is obtained, as shown in fig. 2, in the figure, the first time and the second time correspond to the moment when the rising edge and the falling edge of the A same-phase synchronous square wave signal read the level of the three-phase synchronous square wave, and the other time points are analogized. The synchronous phase sequence of the positive sequence is shown in table 1 below.

TABLE 1 Sync phase sequence under Positive phase sequence

The negative-sequence synchrotron phase-sequence is shown in table 2 below.

TABLE 2 synchrous phase sequence under negative phase sequence

According to the obtained synchronous phase sequence, the positive sequence and the negative sequence of the synchronous phase sequence are determined, and taking the determination of the synchronous phase sequence by using the rising edge as an example, see fig. 3, the following is detailed:

after detecting the rising edge of the A sync signal, the programmable logic chip reads and records A, B the level of the C sync signal, and B and C are the same. After one cycle of processing, if the octal sequence number is 563, the synchronous phase sequence of the positive sequence is determined, and if the octal sequence number is 635, the synchronous phase sequence of the negative sequence is determined.

The principle of synchronous phase sequence judgment by using the falling edge is consistent with that of the rising edge.

Step three: when the synchronous phase sequence is a positive sequence, the excitation system can work normally. When the synchronous phase sequence is negative, the synchronous transformer (Y/delta-11) lags behind the phase of 30 degrees, the synchronous voltage detection board delta/Y-11 lags behind the phase of 30 degrees, and the synchronous RC filter lags behind the phase of 90 degrees, so that the phase of the synchronous square wave signal lags behind the original phase voltage by 150 degrees in electrical angle. Referring to fig. 4, in the negative sequence case, the B-phase voltage changes from a positive sequence lagging the a-phase by 120 ° to leading the a-phase by 120 °. Therefore, the phase B is used as the phase A synchronous signal, the phase lags by 30 degrees, and the natural commutation point of the phase A thyristor is just corresponded. Similarly, phase C is used as the B same synchronization signal, and phase A is used as the C same synchronization signal. Therefore, under the condition of positive sequence voltage and negative sequence voltage, different signals are respectively adopted for synchronization, trigger pulses are respectively generated, and selection and switching control of output pulses are completed through the positive sequence/negative sequence switch.

The trigger pulse of the controllable silicon is divided into a single pulse, a double narrow pulse and a pulse group, wherein the double narrow pulse is widely applied. The first pulse signal of the double narrow pulses is generated according to the synchronous signal, the second pulse signal is generated after the next pulse for conducting the controllable silicon, and the trigger pulse sequence of the controllable silicon of the three-phase fully-controlled rectifier bridge under the positive sequence phase sequence is shown in fig. 5. In the figure, 1 and 7 are the + A phase and-A phase silicon controlled pulses generated according to the synchronous rising edge and falling edge delay angles of the A phase; 5 and 11 are the + B phase and-B phase silicon controlled pulses generated according to the delay angle of the synchronous rising edge and the falling edge of the B phase; 9 and 3 are the + C phase and-C phase silicon controlled pulses generated according to the synchronous rising edge and falling edge delay angles of the C phase, and 2, 4, 6, 8, 10 and 12 are complementary pulses.

The delay angle is generated after closed-loop adjustment of the CPU, and the value of the delay angle is written into the logic chip through the bus. And (4) delaying after the rising edge, wherein the time is equivalent to an angle, and generating the controllable silicon pulse after the delay.

The conduction sequence of the controllable silicon under the positive sequence is VT6/VT1 → VT1/VT2 → VT2/VT3 → VT3/VT4 → VT4/VT5 → VT5/VT6 → VT6/VT 1. "/" indicates that: the two thyristors are now conducting.

The trigger pulse sequence of the three-phase fully-controlled rectifier bridge thyristor under the negative sequence phase sequence is shown in figure 6. FIGS. 1 and 7 show the + A phase and-A phase thyristor pulses generated based on the synchronous rising and falling edge delay angles of phase B; 5 and 11 are controlled silicon pulses of + B phase and-B phase generated according to the synchronous rising edge and falling edge delay angles of the C phase; 9 and 3 are the + C phase and-C phase silicon controlled pulses generated according to the synchronous rising edge and falling edge delay angles of the A phase, and 2, 4, 6, 8, 10 and 12 are complementary pulses. The conduction sequence of the controllable silicon under the negative sequence is VT1/VT6 → VT6/VT5 → VT5/VT4 → VT4/VT3 → VT3/VT2 → VT2/VT1 → VT1/VT 6.