Abstract: Introduced based on the DS80C320 host from the contravariant power source supervisory system’s design proposal, from the hardware architecture, the software establishment and the antijamming measure three aspects has carried on the detailed discussion, and has carried on the introduction to the monolithic integrated circuit phase lock technique. The actual movement indicated that this supervisory system satisfies the actual need completely, the performance is good.
Key word: Monolithic integrated circuit; Contravariant power source; Phase-lock; Antijamming
Introduction
This supervisory system is main inverts the electrical power system design for the railroad with 4kVA/25Hz from the hot backup.
4kVA/25Hz main from the contravariant power source is the electric railway sector signaling system’s key equipment, two output: 110V/1.6kVA partial voltage (A); 220V/2.4kVA track voltage (B); Two are 25Hz, and requests A permanent in advance B 90°. Because the invertor is for the important load power supply, and the load does not permit the power failure, therefore uses the hot backup system, once the main engine breaks down, requests to realize the cut in the scheduled time, therefore, the backup invertor has been at the starting condition. Because the invertor passed through the rectification, inverts two level of energy evolutions, the power is big, and the target request is high, must use the advanced control technology; Simultaneously to realize safely main from the cut, must probably have the consummation supervisory system to realize the phase-lock, the guarantee complete machine security.
1 supervisory system system design request
According to the actual situation, this system mainly completes the following function:
1) main realizes the accurate cut from the cut function from the control, has automatic and the manual two kind of functions, when the guarantee cut voltage same frequency, with phase, same peak-to-peak value;
2) phase-lock function main from unit partial voltage frequency synchronism, in identical unit A permanent in advance B 90°;
3) consummates the protection function has the soft start function, avoids starting the instantaneous voltage overswing to the invertor and the load impact, as well as outputs the pressure, the overflow protection, the frequency, the phase out-of-tolerance protection, the bridge arm has gone nonstop to the protection, overheated protection and so on;
4) demonstrated that the function real time display operational factor and the active status and have the acousto-optics warning function, prompts the attendants prompt trouble clearing;
5) corresponds the function to have main corresponds from the unit, (superior machine) corresponds and so on functions with the monitoring center;
6) the antijamming functional system has the good antijamming ability.
2 system hardware circuit design
2.1 DS80C320 monolithic integrated circuit synopsis
DS80C320 is the DALLAS Corporation’s high speed low power loss 8 monolithic integrated circuits. It and 80C31/80C32 are compatible, use standard 8051 sets of instructions. Compares below with the ordinary monolithic integrated circuit has the new characteristic:
1) was the P1 mouth has defined the second function, thus altogether had 13 interrupt sources (external interrupt 6), 3 16 fixed time/counters, two full-duplex hard serial ports;
2) the high speed performance, 4 clock cycle/machine cycle, the highest oscilation frequency may reach 33MHz, double data indicator DPTR;
3) built-in programmable watch-dog timer, power failure reset circuit;
4) provides DIP, PLCC and the TQFP three kind of seals.
2.2 based on DS80C320 supervisory system hardware circuit design
According to the above system design request, has designed the supervisory system which as shown in Figure 1. The supervisory system uses modular the design concept, divides into the microprocessor and the peripheral device module, the simulation quantity gathering module, the switch quantity gathering module, the frequency and the phase difference survey module, the control quantity output module, the man-machine interface module, the synchronized signal module as well as the connection module.
1) the microprocessor and the peripheral device module microprocessor uses DS80C320, very suitably in monitoring. Front this system full use mentioned the characteristic, simplified the hardware design and the programming, thus enhanced overall system’s reliability. Needed to expand one piece according to the system 8255, piece of E2PROM and a piece 8254.
2) simulates the quantity gathering module according to the gathering accuracy requirement as well as is gathered the quantity change slow characteristic, uses AD Corporation’s high speed 12 to approach type modulus switch AD574A gradually, its internal integration has the transformation clock, the reference potential source and the three states of matter output latch, the switching time 25μs, and through ADG508A expansion simulation quantity input channel.
after 3) the switch quantity gathering module first passes through the light pair carries on the isolation, then through and gate sends in monolithic integrated circuit’s exterior fracture, simultaneously through 8255 sends in the monolithic integrated circuit, way which after adopting interrupts first, inquires.
4) the frequency and the phase difference survey module signal the process has the sluggish characteristic zero crossing comparator to transform first into the square-wave, then four chooses a switch through the pair 4052 to send in the monolithic integrated circuit, calculates the frequency and the phase difference through timer T0.
5) controls the quantity output module transmitted light pair control output, realizes the reliable isolation.
6) man-machine interface module including pressed key and demonstration part. Through the simple pressed key choice, realizes the electric current, the voltage, the frequency and the phase difference demonstration. The demonstration part uses 8279 actuates 8 LED to demonstrate, simultaneously through light emitter diode and buzzer prompt running status.
7) synchronized signal module this module uses for to realize the phase-lock. The monolithic integrated circuit controls 8254 produces the partial synchropulse and the track synchropulse, the synchropulse uses for to reposition the sine datum. Through the software control synchronized signal’s frequency, may realize main from the phase-lock and partial and track’s phase track. Will realize the process specifically in as follows specification.
the connection module has used RS232 and RS485LIANG the mailing address. 0 use RS232 using the serial port to realize monitors the unit with another unit the correspondence, gains opposite party unit status messages; 1 uses the RS485 standard interface using the serial port to realize with the superior machine correspondence, completes functions and so on transmission data and long-distance warning.
3 system software designs
3.1 system software flows
Master routine flow chart as shown in Figure 2. On after system electricity replacement, first to the monolithic integrated circuit, the periphery chip and the control state carries on the initialization; Then reads the AC/DC module the active status, if normal, then starts the DC/AC module, otherwise transfers the failure processing; After opening DC/AC, reads in its active status and judges the output voltage whether to satisfy requests, has the breakdown to transfer the failure processing, normal, then opening breakdown interrupt; Then carries on main from the unit judgment and the phase track, realizes main from the phase sync and partial and the orbital voltage phase-lock; Only then after realizing the phase-lock, only then uses the inquiry way processing keyboard and the survey demonstration. In the software establishment, the keyboard interrupt is the closure. The experiment proved that uses this inquiry processing method to the man-machine interaction channel, definitely may satisfy system’s real-time request. The switch quantity’s input adopts has the interrupt first, latter inquires the method, has guaranteed the response timeliness and the contravariant system’s security.
3.2 systems use main algorithm and technology
3.2.1 exchange sampling algorithm
The survey demonstrated when big signal exchange quantity, obtains through the mutual inductor suits the exchange small signal which A/D transforms, then carries on the sampling to the small signal, finally uses certain algorithm to the sampled data, obtains the correct demonstration value. The root-mean-square law is present commonly used algorithm, its basic philosophy is rests on the cyclical continuous function the effective value definition, continuous function discretization, thus obtains the voltage the expression
In the formula: n is each cyclical even sampling points;
ui is the ith spot voltage sampling value.
3.2.2 digital filtering algorithm
When A/D transformation, is possibly received by the sampling signal disturbs, the software algorithm which withdraws from the sampled data row approaches when true value data uses, is called the digital filtering algorithm. At present the commonly used method has the procedure to judge the filter, the value filter, the arithmetic mean filter, the weighted average filter, the running mean filter and so on. To gathers the precision according to this system to have the high request as well as the simulation quantity change slow characteristic which gathers, uses filter method which the procedure judgment filtering and the arithmetic mean filter law unifies, namely carries on the multi-cyclical sampling, takes its arithmetic mean value to take the effective sampling value. After each time sampling, and previous effective sampling value comparison, if the change scope does not surpass certain peak-to-peak value, the sampling is effective; Otherwise regards as gives up invalid.
3.2.3 monolithic integrated circuit phase lock technique
This supervisory system very important function realizes the phase sync, namely guarantees main from unit’s phase sync and the unit the partial voltage phase permanent in advance track voltage phase 90°. This system phase-lock’s basic principle is, regarding the frequency is the same, but phase not synchronization two groups signals, for instance A road and B group, if A group is a datum, B group (lag) certain phase, may through reduce suitably in advance (increases) B group signal frequency to realize the phasing then phase-lock, finally sets at again B group frequency for the original frequency value.
In this system, the monolithic integrated circuit controls 8254 produces the 25Hz synchropulse, the synchropulse uses for to reposition the sine datum, causes the datum sine wave again from zero value start. The datum sine wave and the triangular wave comparison have the SPWM wave, obtains after the inversion with the datum sine frequency exchange output, therefore, may change the sine datum through the adjustment synchropulse’s frequency the frequency, then may change is adjusted the output voltage the phase. Must realize system’s phase-lock request, needs to track the main unit from the unit partial voltage the partial voltage, various units track voltage tracks this unit the partial voltage. Therefore, must have main tracks two sub-procedures from the partial phase-lock and the partial orbital phase.
Phase-lock’s flow chart like chart 3 and shown in Figure 4. First wants phase-lock’s two groups signals by the multiway switch choices, by the monolithic integrated circuit survey phase difference, and carries on the essential operation and processing after the obtained phase difference data, judges whether there is the out-of-tolerance. If phase out-of-tolerance, according to out-of-tolerance scope determination synchropulse frequency value. If is advocates from the partial phase-lock, should simultaneously change from the unit partial and track’s synchropulse; Otherwise, if for partial, orbital phase track, then only changes this unit track’s synchropulse. Through the adjustment synchropulse, may realize the phasing. After realizing the phase-lock, synchropulse’s frequency sets is the 25Hz returns.
4 antijamming measures
Because this supervisory system works Yu Qiangdian the environment, very easy to receive each kind of disturbance the influence. Once the disturbance the string enters the system, light will cause the misinformation, will be serious when will cause the overall system paralysis, will create the heavy accident. This system has taken the antijamming measure from the hardware and the software two aspects, has guaranteed supervisory system’s reliability service.
4.1 hardware antijamming measure
1) the electro-optical isolation in inputs and on the output channel uses the light coupled apparatus to carry on the intelligence transmission, in electrical general the monolithic integrated circuit with each kind of sensor, the switch, the implementing agency isolates, may prevent the string mold disturbance well.
2) adds the decoupling circuit to enter the terminal in the power source to add the decoupling electric capacity, weakens each kind of high frequency interference.
3) in the reasonable arrangement ground system’s digit separates with the simulation, finally was connected in a spot, has avoided the digital signal to the simulated signal disturbance.
4) the digital signal uses negative logical transmission harassment source function in the high-resistance line when easy to form disturbs greatly, but when the digital signaling system, outputs the low level the interface resistance wants small, therefore, defines the low level for effective (to enable) the signal, the high level is the invalid signal, may reduce the misoperation which the disturbance causes, enhances the control signal the reliability.
4.2 software antijamming measure
1) uses the programmable hard logical watch-dog and runs the monolithic integrated circuit from the endless loop flies in the condition to pull out, causes the monolithic integrated circuit to reposition. But DS80C320 has provided the internal programmable hard logic watch-dog, cannot the sur- electric circuit, be able to realize the reliable overtime replacement. At the same time, DS80C320 has also provided the visit protection for some important watch-dog control position, after preventing the monolithic integrated circuit out of control, carries on the illegal operation to these important control position, has further guaranteed the procedure security.
2) regarding digital signal gathering, assumes the wool using the unwanted signal spinous, and the response time short this characteristic, is many times redundant gathers, gathers the result until continual two or two times above completely only then to think effectively. When digital signal output, the redundant output identical data, its repetition interval is as far as possible short, causes the external instrumentation to make the effective response without enough time to the unwanted signal.
3) to simulates the quantity the sampling and processing, uses the digital filtering technology.
4) uses the instruction redundancy and the software trap, prevents the procedure to run flies.
5 conclusions
This supervisory system has developed produces the prototype. The practice proved that the system performance is fine, satisfies the contravariant system request completely, has the very good antijamming ability, had guaranteed the complete machine safe, moves reliably.
