CN203278626U - Microcomputer triggering control device of thyristor rectifier circuit - Google Patents

Abstract

The utility model discloses a microcomputer triggering control device of a thyristor rectifier circuit. The microcomputer triggering control device comprises an MCU, a given signal generating circuit, a voltage transformer, a current transformer, an A/D converter, a synchronous signal acquisition circuit, an LED lamp, a pulse forming circuit and a power amplification circuit. The output signals of the given signal generating circuit, the voltage transformer and the current transformer are connected with an input end of the A/D converter. An output end of the A/D converter and an output end of the synchronous signal acquisition circuit are connected with an input port of the MCU. An output part of the MCU is connected with an input end of the pulse forming circuit. An output end of the pulse forming circuit is connected the power amplification circuit. The power amplification circuit outputs six paths of triggering pulse to triggering ends of six thyristors in the thyristor rectifier circuit. The LED lamp is connected with the MCU. According to the microcomputer triggering control device of the thyristor rectifier circuit, the long-term stable operation of the rectifier circuit can be ensured, and the stability of output voltage is high.

Description

A kind of microcomputer trigger control device of scr rectification circuit

Technical field

The utility model belongs to the application of power electronics in electric power system, relates to a kind of microcomputer trigger control device of scr rectification circuit.

Background technology

Rectifying device is widely used in many industrial circles.In the industries such as electric power, chemical industry, metallurgy, iron and steel, thyristor rectifier is usually in the critical workflow for the production of technique, will cause great economic loss in case thyristor rectifier breaks down, guarantee that therefore the reliable and stable triggering operation of thyristor rectifier device seems particularly important.And trigger control circuit is the core control technology of thyristor electric power unsteady flow, due to controlled device complexity and the time variation of rectifying device, keeps the stable of rectifying device output, and makes each controlling unit reasonably be connected to reach optimal control to seem particularly important.Therefore to go out control precision high for research and design, rapid dynamic response speed, and the pulse-control system that antijamming capability is strong has important theory significance and practical value.

The problem that the pulse trigger that uses at present exists is as follows:

1. there is phase difference between voltage sample synchronizing signal and three-phase mains voltage.In traditional arteries and veins trigger equipment, what usually adopt is the three-phase synchronous transformer, adopts that this mode obtains synchronizing signal, hardware circuit is simple.But maybe when power phase shortage occurring, the voltage-phase of transformer output is often asymmetric for the asymmetry that itself may exist due to the three-phase synchronous transformer, and the trigger impulse that produces is asymmetric or pulse is disorderly thereby cause.

2. the poor reliability of trigger impulse.Pulse-triggered mode commonly used has two burst pulses to trigger and broad pulse triggers two kinds of forms, may occur the phenomenon of pulse missing during less than power-factor angle when the angle of required Trigger Angle, and when the triggering of employing broad pulse, the gate pole loss of thyristor increase.

Therefore, be necessary to design a kind of microcomputer trigger control device of scr rectification circuit.

The utility model content

Technical problem to be solved in the utility model is to provide a kind of microcomputer trigger control device of scr rectification circuit, the microcomputer trigger control device of this scr rectification circuit can guarantee rectification circuit operation steady in a long-term, and output voltage (electric current) stability is high.

The technical solution of utility model is as follows:

A kind of microcomputer trigger control device of scr rectification circuit comprises MCU, given signal generating circuit, voltage transformer, current transformer, A/D converter, synchronous signal obtaining circuit, LED lamp, pulse shaping circuit and power amplification circuit;

The output signal of given signal generating circuit, voltage transformer summation current transformer is all joined with the input of A/D converter; The output of the output of A/D converter and synchronous signal obtaining circuit all is connected with the input port of MCU;

The output port of MCU connects the input of pulse shaping circuit, and the output of pulse shaping circuit connects power amplification circuit; The trigger end of 6 thyristors of power amplification circuit output 6 road trigger impulses in the scr rectification circuit;

The LED lamp is connected with MCU.

Described MCU is the MPC89E52 processor; Pulse shaping circuit is 6 road generation of doubled pulses circuit based on latch 74HCT174; A/D converter adopts the TLC1543 chip.

Beneficial effect:

The microcomputer trigger control device of scr rectification circuit of the present utility model, on the basis of single-chip microcomputer MPC89E52, digital trigger and digital governer are combined, consist of a kind of rectification digit pulse trigger control device that collects pulse-triggered and be controlled to be one, the trigger impulse real-time that produces is good, control precision and extent of stability are high, applied widely, by evidence, this Pulse-trigger control device can guarantee the operation of rectification circuit long-term stability, by closed-loop control, ensure that output voltage (electric current) stability is high.

Description of drawings

Fig. 1 is the utility model overall structure schematic diagram;

Fig. 2 is the major loop winding diagram;

Fig. 3 is the schematic diagram of synchronous signal obtaining circuit;

Fig. 4 is signals collecting and treatment circuit;

Fig. 5 is that trigger impulse produces circuit;

Fig. 6 is the trigger impulse power amplification circuit;

Fig. 7 is that fault detects and the judgement block diagram;

Fig. 8 is the operation circuit block diagram.

Embodiment

Below with reference to the drawings and specific embodiments, the utility model is described in further details:

Embodiment 1:

1, overall structure

Power supply is three-phase alternating voltage 380V, and after power supply/synchrotrans, the one tunnel provides direct current as D.C. regulated power supply for device, and the detection of synchronizing signal is carried out through corresponding circuit in another road.

The power supply that adopts provides power supply for trigger control device, it is input as the 380V industrial frequency AC, be output as+5V ,+15V and+the 24V direct current, wherein+5V and+15V provides working power for each control chip in device ,+24V provides power supply for pulse amplification module and actuating of relay module.

as shown in Figure 1, at first detect judgement by three phase mains being carried out phase sequence, determine phase sequence and phase shortage whether, given signal, the feedback of voltage and current signal inputs to A/D converter after processing by signal conditioning circuit, A/D converter compares given and feedback, carry out the PID computing by single-chip microcomputer and obtain Trigger Angle α, through on-line debugging and analysis, final pid parameter is, P=9, I=3, D=0.02, under this parameter, output can rise to specified process duration from 0 and be about 5s, dynamic property is good, stable state accuracy is high, voltage fluctuation is in 0.5V.single-chip microcomputer produces suitable trigger impulse from trigger 74HCT174 according to different phase sequences, wherein, INH and AMC are control signal, the soft start of control device and manually adjusting automatically respectively, when breaking down in running, after detecting, single-chip microcomputer sends the Reflector signal, action and the malfunction indicator lamp of control relay are indicated, the effect of X5045 watchdog chip is: power down is protected to CPU on the one hand, in case CPU power down, the parameter on the paired pulses control board is preserved, on the other hand, in the process of debugging, X5045 is serving as the storage setting parameter.

2, major loop

At present in various rectification circuits, silicon controlled rectifier, its feature is that capacity is large, power bracket is wide, in the nominal load situation, can obtain gratifying precision, ripple and efficient, particularly on efficient, than the semiconductor device in past, significant raising arranged.And price is not high, and the lead time is short.On performance, controllable silicon not only has unilateral conduction, and it only has the turn-on and turn-off two states.What therefore be most widely used is the three-phase thyristor bridge rectification circuit.

Be illustrated in figure 2 as the main circuit of three-phase full-bridge controlled rectifier; major loop exchanges 380 volts through air switch (overcurrent by power-frequency voltage; overvoltage protection) deliver to step-up transformer to relay, and be that direct voltage is to load by the rectification of Thyristor Three-phase bridge-type all controlled rectifier circuit after fast acting fuse.

Three-phase full-bridge controlled rectifier has six brachium pontis, and a controllable silicon is arranged on each brachium pontis, and wherein VT1, VT3, VT5 negative electrode connect together, and anode is connected to respectively U, V, W three-phase alternating-current supply, consists of the common cathode group and connects; VT2, VT4, VT6 anode connect together, and negative electrode is connected to respectively U, V, W three-phase alternating-current supply, consist of common anode utmost point group and connect.Any moment all has 2 thyristor conductings simultaneously, forms the load supplying loop, and 1 of these two thyristor are from common cathode group (VTI, VT3, VT5), 1 is come common anode utmost point group (VT4 naturally, VT6, VT2), and can not be with two thyristors on brachium pontis.

3, synchronous signal obtaining circuit

Synchronous signal obtaining circuit offset of sinusoidal alternating current is processed and is changed, finally being converted to amplitude is to be the square-wave signal of 20ms in the 5V cycle, this square wave signal is delivered to single-chip microcomputer and is carried out phase sequence detection and judgement, this square wave signal has 3 the tunnel, be connected to respectively P3.0, P3.2 and the P3.3 of single-chip microcomputer, wherein P3.2 and P3.3 are the input of external interrupt, by checking the relation of 3 road square-wave signals, judge the phase sequence of power supply and phase shortage whether.

as shown in Figure 3, UV line voltage becomes the AC signal of 5V (effective value) after transformer pressure-reducing, be also the second tunnel output of T1 transformer, through the RC filter circuit, on the one hand in order to eliminate harmonic wave in electrical network to the impact of synchronizing signal, next is additional the shifting to that produces 30 degree, then through D20 is arranged, R52, the circuit and square-wave that R53 and operational amplifier consist of forms square-wave signal, in order to prevent the shake of square-wave signal, keep the stable of square-wave signal, increased again inverter, afterwards in order to prevent that outer signals is to the interference of square-wave signal, added again light to isolate every TLP521-1, the square-wave signal of stable output afterwards.

4, signals collecting and processing

Because voltage feedback signal is 0-10V voltage, given signal is the d. c. voltage signal of 0-15V, and the voltage range that A/D converter can receive is 0-5V voltage, therefore voltage feedback signal and given signal need to be converted to the voltage signal that A/D converter can receive, Fig. 4 is the treatment circuit of voltage feedback signal and given signal.

as shown in Figure 4, voltage feedback signal UF and given signal SV are through electric resistance partial pressure, amplitude reduces by half, wherein C12 and C11 are filter capacitor, the alternating component that may exist in elimination UF and SV, B1 is integrated silicon bridge, model is 2W10, it is equivalent to the amplitude limiter circuit that four diodes form, its effect with voltage feedback signal and given signal limiting between 0.7V-5V, signal after processing is received and is converted to digital signal on A/D converter, A/D converter passes through given and comparison feedback signal, draw difference between the two, then obtain suitable Trigger Angle by the PID computing, it is also the angle of flow of thyristor.

5, trigger impulse produces

pulse-triggered with shift to just contrary according to detected phase sequence of control module, and the size of delay angle produces corresponding trigger impulse, trigger impulse is produced jointly by single-chip microcomputer and latch 74HCT174, trigger impulse is that 2 width are two burst pulses of 30 degree, two pulses be spaced apart 60 the degree, pulse amplitude is 5V, and this trigger impulse can be according to level and smooth the shifting in big or small left and right of Trigger Angle, do not possess the ability that keeps high level due to the thyristor triggering impulse transformer, short of width by the trigger impulse of pulse transformer output, can not satisfy the desired width of thyristor triggered as normal, so, thyristor triggers and will go wrong, the phenomenon of triggering may appear not triggering or leaking, will cause the direct voltage of rectification output to occur interrupted, whole thyristor rectifier system cisco unity malfunction, in order to address this problem, usually the method that adopts is to adopt analog circuit or digital circuit to generate the trigger impulse that high-frequency impulse is listed as to replace the thyristor certain width.In order to produce the high-frequency impulse row, when adopting Two-pulse triggering, require each trigger impulse for sequence of high frequency pulses, in native system, in order to produce high frequency trigger impulse row, the relaxation oscillator circuit that adopts 74HC14 to form.

74HCT174 is six rising edge D-latchs, and the clock pulse rising edge deposits D pin level state in latch, and the latch state only has last rising edge clock D state.74HCT174 /CLR is that high level is effective, and when CLR was low level, no matter why CLK and Dn are worth, output was all low level, and the rising edge that is high level and CLK as CLR comes temporarily, and the value of output Qn is the value of Dn.

The circuit diagram that pulse-triggered produces as shown in Figure 5, because the P0 mouth of single-chip microcomputer is opened the utmost point, there is no driving force, so say single-chip microcomputer P0.1-P0.6 be connected to the input port D1-D6 of 74HCT174 by the pull-up resistor of 1k, the ALE of single-chip microcomputer is connected to the CLK of 74HCT174, for it provides clock signal.

after carrying out phase sequence detection and trouble shooting, if there is no fault, sample and pass through the Trigger Angle that the PID computing obtains thyristor through A/D converter, need to carry out pulse-triggered this moment, trigger impulse is realized jointly by single-chip microcomputer and latch 74HCT174, the single-chip microcomputer P1.0 output cycle is the square wave of 3.3333ms (60 °), each 1.6667ms of height (30 °) is after oscillating circuit, each cycle becomes 26 small-pulse effect row, be used as the CLR of 74HCT174, and P0.1-P0.6 is connected to six tunnel inputs of 74HCT174, so the output of 74HCT174 is deformed into six road trigger impulses, wherein every road trigger impulse is all two burst pulses row of 30 °.when phase sequence is positive sequence, take the g1 trigger impulse as example, number one thyristor in the corresponding three-phase full-controlled rectifier bridge of g1 trigger impulse, the output of g1 trigger impulse is P1.0 and the decision of P0.1 co-controlling again, when and if only if P1.0 is high for low P0.1 is output as, just export the g1 trigger impulse, and the width of g1 trigger impulse equates with the low level width of P1.0, the width that so just produces is the trigger impulse of 30 °, P1.0 sets high afterwards, no pulse output, due to the two burst pulses of needs, so the high level of P0.1 is 120 °, also namely in one-period, P0.1 is the high level of 120 °, the low level of 240 °, 60 ° of g2 trigger impulse hysteresis g1 trigger impulses, 60 ° of g3 trigger impulse hysteresis g3 trigger impulses, the like, therefore the P0.1-P0.6 waveform lags behind 60 ° successively, g1-g6 waveform Sequential output.

6, trigger impulse power amplification

Because the power of two burst pulses of latch 74HCT174 output is less, can not directly drive the thyristor conducting, must add the power amplification link.From latch output six tunnel phase shift triggering signals, through the power amplification of extra pulse amplification board, after exporting to the three-phase full-controlled rectifier bridge of cowling panel, obtain VD.Pulse amplifying circuit as shown in Figure 6, MOSFET carries out power amplification to trigger impulse, the normal operation of light-emitting diode indication trigger impulse, in figure, voltage stabilizing didoe VS1 is when metal-oxide-semiconductor ends, through the afterflow of pulse transformer primary side coil.When P0.1 is high level, the metal-oxide-semiconductor conducting, lumination of light emitting diode, pulse is transferred to secondary by transformer.The diode of pulse transformer secondary has the effect of rectification, can extend the width of high frequency trigger impulse.R7 is current-limiting resistance, and R56 can discharge energy by pulse transformer when metal-oxide-semiconductor becomes cut-off by conducting.Pulse transformer is selected the magnificent electronics KMB518/301 transformer of credit, and this transformer input pulse voltage swing is 24V, and the output pulse amplitude is greater than 6V, and electric current is greater than the gate trigger current of thyristor, and GA+, KA+ connect gate pole and the anode of thyristor.The effect of diode D7 is, guaranteed that the G1 point voltage can be lower than the K1 point, and D1 is fly-wheel diode.

7, fault detect and judgement

After device energising start, single-chip microcomputer powers on, at first single-chip microcomputer carries out fault detect to device, the project that detects comprise single-chip microcomputer, A/D converter chip, power supply whether phase shortage, whether enter debugging mode, overcurrent etc. whether, detect rear if there is fault, carry out corresponding Error Display Program and send alarm signal, return to main program after trouble shooting.If there is no fault, opens interrupters carries out that phase sequence detects, A/D converter begins to sample and according to different phase sequences provide for trigger impulse.So fault judgement and detection are guarantees of device normal operation, examine by fault, can know easily where occurred problem in system, in order in time solve, for maintenance brings convenience, on the other hand, if system breaks down, by fault detect, send fault-signal, and automatically cut off trigger impulse, control corresponding relay and cut-off, can effectively avoid the generation of accident, minimizing hinders the loss that causes for some reason.The flow chart of fault detect and action is illustrated in fig. 7 shown below.

Fault detect comprises that single-chip microcomputer fault detect, A/D converter failure of chip detect, power supply whether phase shortage, whether enter debugging mode, whether overcurrent and parameter verification mistake.For the single-chip microcomputer fault, the method for detection is that the P3.4 mouth of single-chip microcomputer is connected with light-emitting diode by current-limiting resistance, and diode is the state of going out under normal circumstances, if single-chip microcomputer breaks down, this is that diode does not go out with regard to length is bright, can judge the single-chip microcomputer cisco unity malfunction thus, and solution is, at first check whether crystal oscillating circuit is normal, secondly whether normally starting of oscillation of crystal oscillating circuit is to see whether supply voltage is normal, if all normal, explanation is that single-chip microcomputer damages, and needs to change single-chip microcomputer; The method of A/D converter fault detect is that the digital quantity after the real figure amount of analog signal and A/D converter conversion is compared, if it is too large that error differs, think that A/D converter damages, light-emitting diode dodges and went out one second for three times, and the circulation flicker, need to change A/D converter this moment; Over current fault is the electric current by the sampling circuit under test, compares with the maximum current of setting, if the electric current that sampling obtains is greater than maximum current, circuit overcurrent, indicator light fast blink this moment, and the P1.5 of single-chip microcomputer is set low, make the actuating of relay, cut off the electricity supply.

8, operation circuit

Operation circuit adopts direct current 24V power supply, comprises the power supply separating brake, controls combined floodgate, main road combined floodgate, quick fuse and overcurrent control box fault alarm etc.the power supply separating brake is button SB1, the control switch knob is SB2, KM1 is for controlling closing coil, consist of the combined floodgate self-locking by normally opened contact KM1, the main road switch knob is SB3, KM2 is the main road closing coil, consist of the combined floodgate self-locking by normally opened contact KM2, HL2 is main road combined floodgate indicator light, after major loop closes a floodgate, indicator light HL2 is bright, KA1 is fault sound equipment coil, KA2 is the overcurrent coil, when circuit works, only have the HL2 indicator light bright, when overcurrent appears in circuit, indicator light HL4 is bright, coil KA2 energising, normally opened contact is closed, normally-closed contact disconnects, this moment, normally opened contact KA1 was closed, the fault audible alarm, HL3 is bright for the quick fuse indicator light, the actuating of relay makes normally opened contact KEK closed, fuse blows, the major loop separating brake, after pending fault is removed, pressing the switch knob circuit can work.Fig. 8 is the control chart of operation circuit.

This device can save the trouble that phase sequence detects; device can automatically be judged phase sequence and provide corresponding trigger impulse according to sampled result; the trigger impulse real-time that produces is good; control precision and extent of stability are high; and device possesses fault detect and defencive function, has improved the stability of system works.

Claims (2)

1. the microcomputer trigger control device of a scr rectification circuit, it is characterized in that, comprise MCU, given signal generating circuit, voltage transformer, current transformer, A/D converter, synchronous signal obtaining circuit, LED lamp, pulse shaping circuit and power amplification circuit;

The output signal of given signal generating circuit, voltage transformer summation current transformer is all joined with the input of A/D converter; The output of the output of A/D converter and synchronous signal obtaining circuit all is connected with the input port of MCU;

The output port of MCU connects the input of pulse shaping circuit, and the output of pulse shaping circuit connects power amplification circuit; The trigger end of 6 thyristors of power amplification circuit output 6 road trigger impulses in the scr rectification circuit;

The LED lamp is connected with MCU.

2. the microcomputer trigger control device of scr rectification circuit according to claim 1, is characterized in that, described MCU is the MPC89E52 processor; Pulse shaping circuit is 6 road generation of doubled pulses circuit based on latch 74HCT174; A/D converter adopts the TLC1543 chip.

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