#control system design

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Understanding Control System Design requires an in-depth knowledge of system dynamics, mathematical modeling and control theory. Engineers can explore components, types and tuning methods to design control systems that fulfill even stringent performance specifications thanks to advancements in technology across industries such as aerospace and manufacturing. Regardless of your level of experience or interest in control systems design this book serves as an indispensable guide in navigating through this complex landscape of design and control systems.

A foreword With the development of society, the requirements for service ability are higher and higher, once some important facility power supply systems broke down and cut off the power supply suddenly, will destroy the normal order of the society, even cause great political influence and economic loss. However, the power failure is sudden and strong, the deenergization situation must be considered, so the one that need to accomplish power is incessant, namely is powered by the back up supply at the time of the power supply line black out. The emergency power supply is also called EPS (Emergency Power System) Have the following advantages: ( 1) When the electric wire netting has electricity, in static behavior, there is no noise; While supplying power, the noise is smaller than 60dB. Do not need exhaust fume and resist shock to deal with, have energy-conservation, be environment-friendly, there is no characteristic of the hidden danger of fire; ( 2) Auto-switch, can realize the unattended operation, mutual switching time is 0.1- 0.25s that mains supply and EPS power supply power; ( 3) Bring ability strong year, EPS accommodate the intersection of inductive character and capacitive, and comprehensive apparatus of load, such as the lift, water pump, air blower work the automation equipment, emergency lighting,etc.; ( 4) Operational safety. The host computer life-span reaches the above for twenty-year; ( 5) Adapt to the severe environment. Can put on basement or power distribution room, can also close to, meet an urgent need location of use of load set up by reducing the power supply line in situ. 2 operating principles ( 1) When three phases are normal in main supply, EPS supplies power for load directly all the way, No. one charges accumulator battery through the battery charging unit; ( 2) When three phases are unusual in main supply, the detection device of EPS gives out order immediately, is outputted the three-phase a.c. voltage supply to supply power for load through the inversing device by the direct current of the accumulator battery in 0.1 seconds, the time of supplying power is as 90 minutes; ( 3) EPS supplies power in the course, such as three-phase city power returns to normal, the detection device of EPS gives out order immediately, return to ( 1) in 0.1 seconds Working condition; ( 4) EPS offers and starts the dry joint ( DC24V) long-rangely by force ,Such as detecting DC24V power input, EPS will be switched over and exported to meet an urgent need by force, auto-switch acts; At the time of electroless, EPS work is in the auto-switch state. 3 DSP hardware design This system adopts the Model TMS320F240 DSP device of TI Company as the main control chip, chip instruction execute of this DSP is fast, embedded Flash ROM and RAM, the Administration Module of internal affairs can export the multi-channel PWM wave, include 10 A/D passways of No. 8 and a large number of I/O ports at the same time, when so it constructs the numerical control system, the hardware circuit is simplified greatly. The circuit design of hardware taking DSP chip TMS320LF2407 as the core mainly includes: ( 1) The sample of the emergency power supply to voltage passes circuit implementation of the differentiating. Fig. 2 shows the difference channel that the voltage samples. The sample of the electric current is realized by that Hall's electric current transducer is after filtering the wave, level monitoring. In this design, the exchanging amount needed to calculate its mean value, realized through the rectification, filtering of the sampled value of the instant. [2] Difference channel that the voltage of Fig. 2 samples ( 2) DSP adopts PWM of the timer 1 of EVA module to relatively export to charge control, to reversing and controlling adopting the comparing element 1 of EVA module and comparative output of comparing element 2. Pass the drive electricity that the specialized driver module 2SD315A is the key component The road comes to drive IGBT. 2SD315A driver module is compact, simple to use, reliable, isolate the higher advantage of the voltage. Drive H bridge of the main circuit, only taking plus few outside components with two pieces of 2SD315A module. While connecting driving circuit and IGBT, should notice and is wired it can't be too long, preferably is smaller than 10cm, otherwise will make the driving signal of IGBT interfered with greatly, causes the touching off by mistake of IGBT. In addition, will choose emitter Up and gate electrode of the appropriate collection to drive the resistance according to the characteristic parameters of IGBT. ( 3) DSP gathers and outputs various signals through the mouth of common I/O. Input signals such as fire control, starting up, forcing to reverse, stop, spare,etc., send to I/O mouth through the photoelectric isolating circuit. The control signals of electrical relay, contact apparatus are exported by the supplementary relay by I/O mouth. ( 4) This emergency power supply, to major failures such as overvoltage voltage shortage of the battery, inverter overvoltage, excessive load of the inverter, IGBT trouble,etc., has specially designed the hardware to lock the circuit very much, at the time of systematic power up, it is clear, when the trouble comes, its set, blockade PWM to export at the same time, initiate malfunction interrupt, measures trouble type in the interrupt program of the trouble. Adopt and inquire about the way to the general trouble. ( 5) Ic that DSP gathered the sampling circuit, UH, ib, the working condition of ub isoparameter and trouble type, system that monitors passes CAN bus out to the monitor system of the epistasis. 4 software design μ C/OS-II is a kernel of a real-time operating system, its most source codes use ANSI C to write, there is very strong transplantation. Its kernel function is abundant, can have cutting down nature, users can dispose and compile the condition according to one's own need, cut out the real-time kernel and meet the minimum state of one's own function. In it is at this for system,it have to write by uC/OS-II last procedure and hardware the driver programs of circuit. Utility program from function main () At the beginning,main () The content is as follows: void main(void) { SysInit () ; /*System initiation * / OSInit() ; /*Initialized u C/OS-II * / OSTaskCreate(TaskStart, (void*) 0,(void*) &TaskStk[0][0], 5) ; /*Setting-up initial task * / OSStart() ; /*Beginning many task scheduling * / } Among them,SysInit () The initialisation work to the system mainly includes: Set up correlation parameter and variable, set up various to cut off, and carry on initialisation to every device, OSInit() Used for carrying on initialisation to uC/Os-II operating system. Initial a task TaskStart ') It is a task of setting up other tasks. Then, set up postbox, used in communication among the task, next, spend OSTaskCreate ') Set up the task of different functions in function: SCI communication task SCIComm_Task () , LCD liquid crystal screen breaks the task LCD_Fresh_Task ') , pulse width calculates the task PW_Calculate_Task ') , output voltage of inverter gathers the task Vo_Sample_Task ') , keyboard scans the task Key_Scan_Task ') , clock updating task Time_Fresh_Task () , voltage of city power gathers and monitors the task Vi_Sample_Task ') . The definite principle of task priority is that the operating frequency is the higher, the higher the priority of the task is. The communication between the tasks is realized by sending or accepting the news, signal or data queue. In addition, uC/OS-II transplantation and method of the disposition on F2407 are as follows: (1)It is associated and great to define in OS_ CPU.H, data pattern and heap declaring to be able to be discerned increase the direction. Define 6 functions of the following in OS_ CPU C.C: OSTaskStklnit ( ) , OSTaskCreateHook () , OSTaskSwHOok () , OST&W_lefook () , OSTaskStatHook () , OST3meT5ckHook () . Need define there is only OSTaskStklnit really in fact ') ,Other 5 only need to declare, might not there should be actual contents, these 5 functions need by the interface function of user-defined. (2)Revise the following several in OS_CPU_A.ASM and collect the function: OSStartHighRdy, OSCtxSw, OS1ntCtxSw, OSTickISR. The function of OSStarthighRdy is the most high ready task of the operation priority, this function is by OSStartp function reference, OSStart() Call setting-up in OSInit () Call and with one piece task in tomb plinth; OSCtxSw is a task switch function of grade of a task, the call in the task of this function; OSIntCtxSw is a task switch function of an interrupt level; OSCtxSw is the interrupt servicing function of the clock, the clock interrupt program runs with all and regular and relevant work, for instance time delay, waiting for of the task,etc., will inquire about the task in waiting for state in clock interrupt, judge that it is over to delay time, will carry on task scheduling again. (3)Increase OS_CPU.H, OS_CPU_C.C and OS_ CPU_A.ASM in the main head file INCLUDES.H. Because INCLUDES.H is a main head file, it will be called by all final-stage. The file of C includes. During transplantation, need to rewrite this file, increase the following files in the file end: #include #include #include (4)In the configuration file OS_CFG.H, defines the major issue is counted the most, most memory deblock and count, most news team's column numbers, the mulitasking is counted the most, the lowest task priority, the enabling signal can enable, allow the postbox and can enable, whether allow the message queuing and can enable, the clock beat counts and some miscellaneous dispositions. Through revise arrangement the, can go on, cut out to uC/OS-II, make the intersection of adaptation and concrete need of system this it. System adopt interrupt mode receive order of upper computer, adopt, inquire way send. After the upper computer sends out reading, starts or stops the operational command, the embedded system will be cut off, and send the answer back signal, then operate correspondingly according to the order type received. Transformation algorithm of power 5 This systematic impulse width calculates to adopt the rule to sample the law, the formula such as formula ( 1) : (1) Among them Usm is the amplitude of the sine wave, Utm is the amplitude of the chopping sea, N is the carrier to noise ratio. [1] The ultraharmonic amplitude of the power of alternation is: (2) By (2) The type can find out N the larger, the smaller the ultraharmonic amplitude is. On the basis of the characteristics of part of IGBT, N can't be infinitely great, fetches N =400,Ultraharmonic amplitude Um(n) It is very easy to be filter by the electric-wave filter. While considering that is in IGBT tube in the switch working state to transfer from opening to a cutoff state, easy to produce more long " Tailing " The phenomenon, and then cause IGBT to influence the reliability of EPS inverter because the instant power consumption is simply big, so, are using the formula (1) There are at the time of pulse width on what has been calculated rectangular wave,it add by feedback element into system, be sampled for lasting control devicing voltage of actual output, regulate and dispel the systematic static error with PI, increase the stability of the system. 6 conclusions This text combines the nuclear advantage in TMS320LF2407 chip and μ C/OS-II real-time operating system, design the emergency power supply control system based on DSP and μ C/OS-II. Through transplanting μ C/OS-II on DSP, the cycle for system design can be reduced, the readability of the software can be improved, thus has saved system development and expenses safeguarded. At present, this system engineering prototype operates steadily reliably. From: http://www.xbgk.com/Technique/TechLunWenView.asp? Aid =4095