The V/F control of transducer and vector are controlled

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The wide modulation of sine arteries and veins of U/f=C (SPWM) control means its characteristic is control circuit structure simple, cost is inferior, physical characteristic hardness is better also, the flowing timing that can satisfy average transmission asks, already got applied extensively in each domains of the industry. But, means of this kind of control is when low frequency, because output voltage is inferior, torsion suffers stator resistor to control falling impact more remarkable, make output the biggest torsion to reduce. Additional, its physical characteristic does not have dc motive after all hard, dynamic torsion ability and static timing function still are like person meaning very much, and curve of not tall, control can follow systematic performance to change ladenly and change, torsion answers utilization rate of torsion of slow, electric machinery not tall, the because of the existence of stator resistor and effect of inverter dead band function when low speed drops, stability becomes poor to wait. Because this people excogitates vector again,control frequency control. Vector is controlled (VC) the practice of frequency control of means vector control is the Ia of stator electric current below, Ib, Ic fastens asynchronous electromotor in three-phase coordinate, through three-phase - 2 photographs commutation, equivalent becomes the alternating current Ia1Ib1 that dormant coordinate department issues two-phase, repass presses rotor magnetic field directional change coming back is changed, equivalent rotates into synchronism the Im1 of dc electric current below coordinate department, It1 (the excitation electric current that Im1 is equivalent to dc motive; The armature electric current that It1 is equivalent to becoming direct ratio with torsion) , imitate the control method of dc motive next, get the control of dc motive to measure, turn over commutation through corresponding coordinate, realize the control of pair of asynchronous electromotor. It is AC motor equivalent is dc motive character actually, be opposite respectively speed, two heft undertake magnetic field be controlled independently. Through dominating rotor linkage, decompose stator electric current next and acquire torsion and magnetic field two heft, via coordinate commutation, realize orthogonality or solution Ou control. Of vector control method put forward to have epoch-making sense. In applying actually however, as a result of rotor linkage hard accurate observation, the effect that systematic character suffers electromotor parameter is bigger, and the place in the process is controlled to rotate with vector in equivalent dc motive commutation is more complex, make the actual result that dominates the effect to obtain good analysis hard. V/F control and vector are constant torsion control. U/F may change relative to torsion a few bigger. And vector adjusts according to the torsion of need, relatively a few worse to control. To common use. Both and same. 1, control of vector of vector control means, the simplest say, pass timing of alternating current machine a series of equivalent commutation namely, equivalent becomes the timing character of dc machine, so simple, as to thorough knowledge, that has to understand the mathematical model of transducer deep, electric machinery learns to wait for course. Vector control principle is the control principle that imitates dc motive, according to the dynamic maths model of asynchronous electromotor, use a series of coordinate commutation to decompose vector of stator electric current for excitation heft and torsion heft, undertake controlling respectively to the heft of torsion electric current of electric machinery and excitation heft. The solution Ou of magnetic field and torsion comes true after rotor magnetic field is directional, achieve the goal that controls asynchronous electromotor torsion thereby, make asynchronous electric machinery gets immediateness the control function of electric machinery of his encourage dc. Particular way is decompose the vector of stator electric current of asynchronous electromotor the voltaic heft to produce magnetic field (excitation electric current) the voltaic heft with generation torsion (torsion electric current) try to control respectively, control two heft at the same time the amplitude between and phasic, control vector of stator electric current namely, say means of this kind of control calls vector to control fashion so. 2, control of V/F of V/F control means, the ratio that is transducer output frequency and output voltage is constant be worth or become scale. For example, voltage of the output when 50HZ is the word of 380V, voltage is outputted to be 190V when 25HZ. When transducer uses V/F to control fashion, depend on to electric machinery parameter not quite, v/f control is to get ideal torsion - speed is characteristic, be based on while frequency of change power source undertakes timing, the thought that should make sure the magnetic flux of electromotor is changeless again and put forward, general-purpose transducer basically uses means of this kind of control. Structure of V/f control transducer is very simple, but this kind of transducer uses open loop to control fashion, cannot achieve higher control performance, and, when low frequency, must undertake torsion is compensated, in order to change character of low frequency torsion. 3, V/F controls fashion this kind multi-purpose at fan, pump kind energy-saving model transducer. Considered electric machinery character and the scale relation of V and F decides beforehand. 4, circumstance of vector pilot application is the transmission circumstance with higher demand commonly. The index of scope of constant torsion timing that asks for instance is high, the range of constant power timing is wider. And, vector control is different from V/F control, it can output the moment of force of 100% when low speed, and because pitching moment is insufficient,V/F control is in when low speed and misfire. 5, V/F controls a characteristic -- it is a purpose in order to control rate, precision of control characteristic control is not tall, when low speed, moment of force is apparently small, commonly used at transducer lug much circumstance falls. Vector is controlled -- it has speed closed circuit, measure an effective rate from laden end namely, undertake comparative with set-point, can get more the speed control of high accuracy, and be when low speed, also have highest pitching moment output. 2, train of thought of principle of vector control system: The target of vector timing -- dc timing; The independence that realizes excitation electric current and armature electric current hard is controlled; Excitation electric current and each other of armature electric current need 90 degrees of part. Principle: Vector pilot fundamental is through measure and controlling report of asynchronous electromotor stator Liushi is measured, according to magnetic field directional principle is opposite respectively the excitation electric current of asynchronous electromotor and control of travel of torsion report inpour, achieve the goal that controls asynchronous electromotor torsion thereby. Specific be decompose the vector of stator electric current of asynchronous electromotor the voltaic heft to produce magnetic field (excitation electric current) the voltaic heft with generation torsion (torsion electric current) try to control respectively, control two heft at the same time the amplitude between and phasic, control vector of stator electric current namely, say means of this kind of control calls vector to control fashion so. Vector control means has again be based on turn means of control of vector of poor frequency pilot, control means and the vector that have speed sensor to control means to wait without speed sensor vector. Quite: Be based on turn means of control of vector of poor frequency pilot is to undertaking U/f = likewise constant on pilot foundation, through detecting the effective rate N of asynchronous electromotor, get corresponding control frequency F, the torsion that gets according to the hope next, control vector of stator electric current and two heft respectively between phasic, to the output of general transducer frequency F has pilot. Be based on turn the biggest characteristic of means of control of vector of poor frequency pilot is, what can eliminate electric current of rules of dynamic process transfer is fluctuant, improved the dynamic performance of general transducer thereby. Inchoate vector controls general transducer basically is use be based on turn vector of poor frequency pilot controls fashion. 3, vector of vector pilot implementation controls basic concept to rotate no matter be the structure in winding,the ground leaves winding magnetic field only, still go up in pilot means, mix dc motive is the most similar. Tentative idea, in two mutual and perpendicular affluent winding are in a turn coming back together, those who connect is dc electric current, they give what signal is decomposed and come by transducer. two through making shift continuously dc signal turns into two-phase communication signal; In via 2 photographs, three-phase commutation gets three-phase communication controls signal; Conclusion wants to control the random in dc signal only, can control three-phase communication to control signal, also controlled the communication output that communicates transducer. Pass afore-mentioned commutation, alternating current machine control is dc machine to control approximately. Vector pilot gives: 1, in vector pilot function, choose " with " or " need not " . 2, after choosing vector to control, the capacity that still needs to input electromotor, extremely number, rated electric current, rated voltage, rated power. The main use linage that vector control is one electromotor is occupied for the basis, accordingly, the moving data of electromotor appears very important, if use the requirement that electromotor accords with transducer, and transducer capacity and be identical of electromotor capacity photograph, transducer searchs for the parameter of electromotor automatically, determine afresh with respect to need otherwise. The parameter that the transducer of a lot of types measures electromotor to go to the lavatory is designed those who arranged electromotor parameter is automatic determine function. Through this function but accurate determine the parameter of electromotor, and the memory that offers transducer is unit, so that be in vector control,use. Vector pilot asks: 1, a transducer can take an electromotor only; 2, of electromotor extremely the requirement that number wants to press a manual, general with 4 very beautiful; 3, the capacity of electromotor capacity and transducer comparatives, need an order and degree at most; 4, cannot grow even the line of transducer and electric parts too, should be in commonly 30m less than, if exceed 30m, after needing good in join cable, undertake self-correcting leaving a line, with determining afresh the relevant parameter of electromotor. Vector pilot advantage: 1, dynamic high speed is answered; 2, low frequency torsion increases; 3, control is quick; Vector controls applied limits of the system: 1, the job that requirement high speed runs is mechanical; 2, get used to harsh working environment; 3, the electric power of high accuracy procrastinates move; 4, 4 quadrant run; What everybody tells above is vector pilot principle and advantage, I think to begin to learn perhaps cannot understand deeper, tell a bit simplier, vector is controlled even if, electric machinery moves at fixed rate, be like laden increase and decrease, what output pitching moment and carry rate what transducer can adjust electric machinery very quickly is constant, namely dynamic high speed is answered, the electric power of high accuracy procrastinates move, and the ability after the speed when laden increase and decrease is like when V/F is controlled can have bigger change moves at former set rate, output to answer set frequency quickly to starting a process, can have the taller torsion that start. At present the main purpose of domestic use transducer is energy-saving with timing, be aimed at diverse use demand so, also appeared to control the transducer with different function: Groovy V/F controls transducer and vector control transducer. Groovy V/F is controlled, the voltage drop of electric machinery is met reduce and increase of speed relatively as electric machinery, because excitation is insufficient,this is brought about and make electric machinery cannot obtain enough torsion (it is especially when low frequency) . Electric machinery cannot be satisfied when groovy V/F controls transducer to be led in low frequency that is to say the output of rated torsion. Additional, in V/F control, user basis is laden circumstance beforehand set curve of a kind of U/f, transducer outputs the change of frequency with respect to the basis when the job, adjust its to output voltage according to curvilinear character, that is to say V/F control is to make transducer works according to the compensation level that has planned beforehand, cannot follow laden change and change. But be in with energy-saving mix for the purpose to speed control precision asks not tall circumstance V/F controls transducer to superior sexual value is compared and receive wide application with its. The fundamental of vector control transducer is, through measure and controlling vector of electric current of asynchronous electromotor stator, according to magnetic field directional principle is opposite respectively the excitation electric current of asynchronous electromotor and control of travel of torsion report inpour, achieve the goal that controls asynchronous electromotor torsion thereby. Specific be decompose the vector of stator electric current of asynchronous electromotor the voltaic heft to produce magnetic field (excitation electric current) the voltaic heft with generation torsion (torsion electric current) try to control respectively, control two heft at the same time the amplitude between and phasic, control vector of stator electric current namely, say means of this kind of control calls vector to control fashion so. Because vector control can make,transducer is mixed according to frequency laden circumstance is real time change output frequency and voltage, because this its trends performance is relative perfect. Can undertake be controllinged accurately to torsion; The system is answered fast; Timing range is wide; It is good to add decelerate performance wait for a characteristic. Controlling the circumstance with high demand to torsion, with its superior control performance gets the admiration of the user. Now a lot of new-style general-purpose transducer also had vector to control a function, just ask to input complete electric machinery parameter when parameter set. Because vector control is,be a basis with the parameter of electric machinery, accordingly complete electric machinery parameter appears especially important, so that transducer can be effective identify electric machinery, very good undertaking to electric machinery vector is controlled controlling is vector control, v/F is controlled even if V/F is controlled, both has substaintial distinction, control function difference is very big " . 1, vector control, V/F control, both is electric machinery frequency control when, to the control of electric machinery magnetic field; 2, V/F control: 1) it is a kind of rough simple control way, namely mode of V/F= fixed value control; 2) its oversight stator winding resistor is pressed fall the IoR influence to magnetic field, mode of V/F= fixed value control, although prevented frequency to drop, the main problem that magnetic field increases, but magnetic field is not constant, be in as frequency however drop, torsion of weak, electric machinery is not worth the magnetic field when causing low frequency; 3, vector control: 1) vector control, not resistor of oversight stator winding is pressed fall the IoR influence to magnetic field, use (V-IoR) / mode of F= fixed value control, or mode of fixed value control of Io= of excitation electric current; 2) it not resistor of oversight stator winding is pressed fall the IoR influence to magnetic field, (V-IoR) / F= controls mode, or mode of fixed value control of Io= of excitation electric current, magnetic field is constant, is not be in as frequency drop, the torsion of weak, electric machinery is not worth nonexistent magnetic field problem when low frequency; 3) if magnetic field can be controlled,go up in parameter of electric machinery design, the moving parameter when frequency control and the impact that are versed in frequency runs parameter are clear, can calculate accurately rotor rotate speed, implementation does not have the speed closed-loop control of speed sensor; 4, vector control, V/F control, because be field control, when means of these two kinds of control is close to labour frequency to move, magnetic field tends consistent, function tends consistent, so difference of these two kinds of pilot basically is carried in low frequency; "' when load increases, when rotor rotate speed drops, turn difference increases, rotor reaction electromotive force, electric current increases, torsion increases, ' complement, electric current is condition of open loop out of control completely, next consequence is IGBT - - Dong - - blare, whole transducer lamp destroys ash flies (extreme view) . " 1, ' when load increases, when rotor rotate speed drops, turn difference increases, rotor reaction electromotive force, electric current increases, torsion increases ' the working torsion principle that is asynchronous electric machinery, had this one, asynchronous electric machinery just ran a few centuries in labour frequency likely! 2, if load is serious overload, asynchronous electric machinery may enter locked-rotor area, if not seasonable power cut jockeys, can burn electric machinery; 3, frequency conversion person knows this truth, so frequency control dominates circuit, set voltaic stall to protect circuit; 4, everybody is done not have ' when load increases, when rotor rotate speed drops, turn difference increases, rotor reaction electromotive force, electric current increases, torsion increases ' with stall protection regards as contradictory, and regard as supplement each other! Groovy V/F is controlled, the voltage drop of electric machinery is met reduce and increase of speed relatively as electric machinery, because excitation is insufficient,this is brought about and make electric machinery cannot obtain enough torsion (it is especially when low frequency) . Electric machinery cannot be satisfied when groovy V/F controls transducer to be led in low frequency that is to say the output of rated torsion. Additional, in V/F control, user basis is laden circumstance beforehand set curve of a kind of U/f, transducer outputs the change of frequency with respect to the basis when the job, adjust its to output voltage according to curvilinear character, that is to say V/F control is to make transducer works according to the compensation level that has planned beforehand, cannot follow laden change and change. But be in with energy-saving mix for the purpose to speed control precision asks not tall circumstance V/F controls transducer to superior sexual value is compared and receive wide application with its. The fundamental of vector control transducer is, through measure and controlling vector of electric current of asynchronous electromotor stator, according to magnetic field directional principle is opposite respectively the excitation electric current of asynchronous electromotor and control of travel of torsion report inpour, achieve the goal that controls asynchronous electromotor torsion thereby. Specific be decompose the vector of stator electric current of asynchronous electromotor the voltaic heft to produce magnetic field (excitation electric current) the voltaic heft with generation torsion (torsion electric current) try to control respectively, control two heft at the same time the amplitude between and phasic, control vector of stator electric current namely, say means of this kind of control calls vector to control fashion so. Because vector control can make,transducer is mixed according to frequency laden circumstance is real time change output frequency and voltage, because this its trends performance is relative perfect. Can undertake be controllinged accurately to torsion; The system is answered fast; Timing range is wide; It is good to add decelerate performance wait for a characteristic. Controlling the circumstance with high demand to torsion, with its superior control performance gets the admiration of the user. Now a lot of new-style general-purpose transducer also had vector to control a function, just ask to input complete electric machinery parameter when parameter set. Because vector control is,be a basis with the parameter of electric machinery, accordingly complete electric machinery parameter appears especially important, so that transducer can be effective identify electric machinery, very good undertake controlling transducer to electric machinery energy-saving and main because energy-saving space exists on craft,be, transducer is used on the electric machinery of nonexistent energy-saving space, can increase power consumption instead, because transducer also should waste partial electric energy. From say to want it to do work only substantially, be about to waste electric energy, change into other energy, because this affirmation wants to abide by law of conversation of energy, and transducer itself has rectification inversion of intermediate dc circuit, this is about to waste electric energy, told it to just increase specific power consumption from this respect, and be not energy-saving. Still see you as to the energy-saving key of transducer how to use. Transducer moves below labour frequency, have section report function, it is a fact. But his premise condition is: The first, high-power and for fan / pump kind laden; the 2nd, device itself has section report function (software supports) ; the 3rd, move for a long time continuously. This is 3 conditions that reflect section report result. Besides, be indifferent to section report, without what meaning. The physical characteristic curve of general AC motor is certain, theory and already proved actually, when laden power is less than the rated power of electromotor, its efficiency as laden torsion decrease and reduce, that is to say, the meeting when electromotor carries gently expends report relatively. And the size self-correcting V/f with meeting laden ground is worth transducer (among them the voltage that V is electromotor stator winding, the voltage change frequency that F is stator winding) , change the physical characteristic curve of electromotor, make its and laden photograph suit, make efficiency gets rising thereby, achieve energy-saving goal CNC Milling