One, since communication servo electric machinery and its timing classification and characteristic are long-term, in the circumstance that asks timing performance is higher, what hold dominant position all the time is the timing system that uses dc motive. But the defect that dc motive puts in a few solid to have, if brush and commutator are easy,wear away, need to often be safeguarded. The meeting when commutator inverting produces scintilla, make the top speed of electromotor is restricted, also make apply an environment to be restricted, and dc motive structure is complex, production difficulty, place is used up with steely material big, production cost is high. And AC motor, especially squirrel-cage induction motor does not have afore-mentioned defect, and rotor inertia relatively dc chance is little, make trends is answered better. Below similar volume, power of AC motor output can raise 10 ﹪ ～ than dc motive 70 ﹪ , in addition, the capacity of AC motor can be built greatly than dc motive, reach taller voltage and rotate speed. Machine tool of contemporary numerical control the tendency introduces communication servo drive, communication servo drive already had the power that replaces dc servo drive. Classification and characteristic 1. What electromotor of servo of asynchronous of electromotor of asynchronous communication servo communication points to is communication induction motor. It has three-phase and single-phase branch, also squirrel-cage and line confuse form, normally multi-purpose squirrel-cage three-phase induction motor. Its structure is simple, compare with the dc motive photograph that is the same as a capacity, quality light 1/2, the price is the 1/3 of dc motive only. Defect is cannot the flowing timing with very wide range of economic ground implementation, must absorb the excitation electric current of lag from electrified wire netting. Make consequently addle of factor of power of electrified wire netting. Abbreviation of electromotor of servo of the asynchronous of rotor of this kind of squirrel cage communication is electromotor of asynchronous communication servo, express with IM. 2. Electromotor of servo of synchronism of electromotor of synchronism communication servo communication although relatively induction motor is complex, but simpler than dc motive. Its stator and induction motor are same, there is symmetrical three-phase winding in stator jacket. And rotor is different however, distribute electromagnetism type and blame electromagnetism form again by different rotor structure two kinds big. Blame electromagnetism type is divided again for magneto and magnetic hysteresis type, reaction type a variety of. Among them magnetic hysteresis type and efficiency of existence of electromotor of reaction type synchronism factor of low, power poorer, production capacity wait for defect not quite. In numerical control machine tool multi-purpose magneto synchronism electromotor. Compare with electromagnetism type photograph, magneto advantage is a structure simple, run reliable, efficiency taller; Defect is bulk the big, character that start owes beautiful. But magneto synchronism electromotor uses tall remanence response, the rare earth of force of tall correct dense kind after magnet, can move over all dimension to make an appointment with small 1/2 than dc, quality reduces 60 ﹪ , rotor inertia decreases the 1/5 of dc motive. It and asynchronous electromotor are compared, because used permanent magnet excitation, eliminated excitation loss and the stray loss that concern, efficiency is so tall. The collector ring that because do not have electromotor of electromagnetism type synchronism,wants again and brush, its machinery dependability and induction (asynchronous) electromotor is identical, and power factor however greatly electromotor of prep above asynchronous, make permanent magnetism somes the volume of electromotor is minorrer than asynchronous electromotor more synchronous thereby. Because be when low speed,this is, induction (asynchronous) electromotor because power factor is low, when outputting power of same have rendered great service, its inspect get greatly in power much, and electromotor is main size is decided in power according to inspecting. 2, the pace enters electric machinery (one) the structure that the pace takes electric machinery and working principle 1. Structural pace is comprised by rotor and stator into electric machinery. Rotor and stator by the silicon steel that takes a tooth-like part of anything piece fold. There is winding cent to be a certain number of photographs on stator 3, 4, 5, 6, 8, 10. Normal Align=center> graph takes a tooth-like part of anything on stator of graph of principle of electric machinery structure and rotor is same, but, on stator each photograph pole tine arranges mutual and stagger photograph to count 1/0 pitch in Zhou Xiang. Each photograph winding can be arranged in radial---Type of radial split phase (graph 4-3) , also can arrange in axial section---Type of axial split phase (graph 4-4) . Graph 4-4 pace enters the pitch Normal Align=center> graph to react type servo pace enters principle of electric machinery structure to pursue 2. Pace of 4-6 of working principle graph enters Normal Align=center> graph, type of split phase of odd stator radial reacts type situation enters electric machinery, photograph number is 3 (three-phase of A, B, C) , stator all cloth 40 tine, pitch horn 9 ° , stator ages on every magnetic pole 5 times, pitch horn also is 9 ° , each extremely tine staggers 3 ° are arranged. When A photograph electrify, tine of photograph pole of the tine of rotor and A is right neat, as a result of,this is each extremely tine staggers 3 ° are arranged, below B photograph, line of rotor tine center lags behind in the counterclockwise line of stator tine center 3 ° , 6 ° lag behind below C photograph (or clockwise lead 3 ° ) . When electrify condition A photograph turns when be B photograph, in report magnetomotivity falls, rotor tine is attracted with B photograph pole tine is opposite neat, rotor suitable hour hand has turned horn of 3 ° step pitch. At this moment, below C photograph, line of rotor tine center lags behind in the counterclockwise line of stator tine center 3 ° , 6 ° lag behind below A photograph (or clockwise lead 3 ° ) . Turn by B photograph again when electrify condition when be C photograph, rotor tine is attracted with C photograph pole tine is opposite neat, rotor arranges hour hand to had turned again horn of 3 ° step pitch. Such, electrify condition presses A, B, C, A, B, C, A---Such appearance sequence is changed ceaselessly, rotor is met enter the suitable hour hand with successive means to rotate with the pace of horn of 3 ° step pitch. If alternate conversely the appearance sequence of electrify condition---A, C, B, A, C, B, A- - , criterion rotor turns over hour hand to rotate. Summary: Normal >1) go up in the structure, stator the tine of each photograph must stagger each other 1/m tine is arranged. M is winding photograph number. Normal >2) electrify condition is changed by fair look sequence. Normal >3) the way that changes electrify photograph order is changeable the direction of rotation of rotor. Normal >4) step pitch horn is: (° ) Normal > type, z, rotor tine number, m, winding photograph number, k, electrify means coefficient. Normal > is odd 3 send open telegram: A-B-C-A- , k=1normal > double 3 send open telegram: AB-BC-BA-AB- , k=1normal > three-phase 6 send open telegram: A-AB-B-BC-C-CA-A- , k=2. Normal >k= number of beats / photograph number. (2) the pace enters electric machinery type to have the job by instruction pulse control into the drive circuit pace of circuit, pulse frequency---Rotate speed, pulse number---Corner. So, advance the working principle of electric machinery according to the pace, pulse instruction should realize the control that runs into electric machinery to the pace, must solve two problems: Normal >1) the demand that presses instruction pulse sequence of electrify condition appearance undertakes allocation, change pulse is strung together string together for condition of each photograph electrify. Normal >2) undertake to pulse power magnifies. This comes true into the drive circuit of electric machinery by the pace, drive circuit basically includes round alloter and power amplifier composition 1. The requirement that alloter of round alloter round realizes to press instruction pulse sequence of electrify condition appearance namely has distributive function. Strong round alloter: By special and compositive chip or general but composition of parts of an apparatus of process designing logic. Be like: CH250 three-phase pace distributes chip into electric machinery annulus. Soft round alloter: Realize the function of round alloter by software. Design soft round alloter by the law that check a watch: Implementation three-phase pace enters electric machinery three-phase the 6 going in a ring that take allocate. Of photograph of the A that the pace enters electric machinery, B, C connect respectively by the PIO of the computer (collateral input / output interface) the state control of the PA0 of A mouth, PA1, PA2, namely: PA0 is 0 when A photograph cuts off the power, PA0 is 1 when A photograph electrify; PA1 is 0 when B photograph cuts off the power, PA1 is 1 when B photograph electrify; PA2 is 0 when C photograph cuts off the power, PA2 is 1 when C photograph electrify. Such, according to three-phase the 6 electrify state laws that take, the output condition that can design round alloter expresses: Normal TEXT-ALIGN of serial number of Center" Align=center> metre: Center" Align=center>Cnormal Align=center>Bnormal Align=center>Anormal TEXT-ALIGN of Center" Align=center> location: Normal Align=center> direction: Center" Align=center>PA2normal Align=center>PA1normal Align=center>PA0normal TEXT-ALIGN of Center" Align=center> address: Normal Align=center> content: Center" Align=center> inverts Normal Align=center>normal Align=center>normal Align=center>normal Align=center>normal Align=center>normal Align=center> is turning Normal Align=center>0normal Align=center>Onormal Align=center>Onormal Align=center>1normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A00Hnormal Align=center>01Hnormal Align=center>1normal Align=center>0normal Align=center>1normal Align=center>1normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A01Hnormal Align=center>03Hnormal Align=center>2normal Align=center>0normal Align=center>1normal Align=center>0normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A02Hnormal Align=center>02Hnormal Align=center>3normal Align=center>1normal Align=center>1normal Align=center>0normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A03Hnormal Align=center>06Hnormal Align=center>4normal Align=center>1normal Align=center>0normal Align=center>0normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A04Hnormal Align=center>04Hnormal Align=center>5normal Align=center>1normal Align=center>0normal Align=center>1normal Align=center>value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A05Hnormal Align=center>05H should have an instruction pulse, with respect to the electrify condition serial number with current foundation, the requirement that electric machinery turns to, find out corresponding and unit address from inside the watch, take out the content of the address, from the A mouth output of PIO. Be like: Turning, current serial number is 2, criterion, serial number + 1=3, the corresponding and unit address that find out is Value="2" HasSpace="False" Negative="False" NumberType="1" TCSC="0">2A03H, take out its content 06H to output the A mouth of PIO from this address, at this moment A mouth is low 3 condition from 010 turn into 110, control electrify state namely from B-BC. To realize the loop of electrify appearance sequence, it is when current serial number 5 (by the watch) when, long instead expresses a serial number. 2. The pulse power that power amplifier outputs as a result of round alloter is very little, accordingly, need power amplifier undertakes enlarge, enter electric machinery with drive pace. Commonly used circuit has the following two kinds. Normal > (1) Normal Align=center> (A) it is circuitry of power supply of a kind of odd voltage. Circuit is shot by 2 class extremely follow implement comprise with reverser of one class power, the first class is shot extremely follow implement have segregation effect. The 2nd class is shot extremely follow implement T2 is in enlarge area, in order to improve result put implement dynamic character. Normal > when round alloter some photograph output is tall n is, the saturation of power canal T3 of this photograph amplifier guides, the direct current source of 60 bend over gives the winding LA of this photograph power supply, the electric current in winding rises to stable state value by exponential rule. When round alloter output is low n, because T1 and T2 are in condition of enlarge of small electric current, t3 does not guide, winding cuts off the power. When T3 by guide turn into when ending, winding inductance will be in two end produce winding very large reaction electromotive force, if be added on T3 together with power source voltage, will caused press puncture. Accordingly, diode of shunt-wound on winding follow on current D2, mix in the collector of T3 shunt-wound RC draws return circuit between radio pole, be not destroyed with T. Normal > establishs ties on winding resistor R0, current limliting of in order to and the time that reduce power supply return are invariable. , shunt-wound capacitance C0 in order to heighten the instantaneous tension of winding, make ascendant rate rises the electric current in winding, raise a pace to enter the starting frequency of electric machinery thereby. Normal > but, after stringing together R, power comsumption increases, to carry stable state electricity, power source voltage increases accordingly, the compression demand that provides to power is higher. To overcome afore-mentioned weakness, appeared circuit of double voltage power supply. (2) amplifier of double voltage power supply pursues 3-4 (B) . The pulse that delivers when round alloter makes T1 canal guides while, spark but D of stable state trigger, what output in D is narrow pulse width year, make T2 guides inside time, high pressure of 60 bend over gives winding power supply, because D bears to be pressed instead, cut off power source of low pressure of 12 bend over. Below high-pressured power supply, the electric current of winding rises quickly, forward position is very steep. When the pulse width that exceeds D output, t canal ends, at this moment, d1 guides, by power supply of low pressure of 12 bend over, need electricity in order to keep place. When T1 canal cuts off the power, of winding make from electrification situation D of diode of follow on current guides, electric current continues to had shed winding. Loop of follow on current is strung together receive resistor to be able to reduce time constant and accelerate process of follow on current. Used above measure to increase the working frequency of electric machinery greatly. Characteristic: Begin tall voltage power supply, make the impulse current in winding rises, forward position is very steep. Benefit starts frequency and frequency of highest and successive job at rising. Hind low voltage power supply is worth with keeping electric current of rated stable state, need very little current limliting resistance only, power comsumption is consequently low. Should work frequency is tall, when its cycle is less than the defer cycle of odd firm D, turn pure high pressure into power supply, can obtain bigger high frequency electric current, have better quadrature frequency character. (3) the application characteristics that the pace takes electric machinery 1. Step pitch error is single-phase when electrify, step pitch error depends on the precision dividing tine of stator and rotor, precision of the amlposition angle of each photograph stator / when polyphase electrify, still concern with the factor such as function of the size of each phase current, magnetic circuit. 2. The highest frequency that start and top job frequency are highest the frequency that start: When carrying for nothing, the pace stops to be started suddenly into electric machinery You Jing, do not break pace ground to enter firm fast move, the allows frequency that start. The highest frequency that start and pace are concerned into the inertial J of electric machinery, j increases the highest frequency that start to drop. Top job frequency: The pace enters the highest frequency that when electric machinery moves continuously, can accept. It and step pitch horn decide to implement the rate of the biggest campaign of the component together. Concern with laden inertia, also put the factor such as class to concern with the result of circuit of means of stator photograph number, electrify, control. 3. The torsion of output---Frequency character because winding itself is perceptual load, input frequency is taller, excitation electric current is smaller. Frequency is tall, magnetic flux quantitative change changes aggravate, eddy current loss is increased. Accordingly, input frequency heighten, output pitching moment to reduce. The output moment of force of top job frequency can achieve low frequency torsion only 40, 50% . 3, dc servo electric machinery and its timing system (one) the timing Normal > by formula: Dc machine timing has 3 kinds of methods: Normal > (1) U of voltage of change cable division: Move downward by rated voltage low, rotate speed also is moved downward by rated rotate speed low, timing scope is big. Normal > (2) change flux Φ (change Ke namely) : The resistor that changes excitation loop is changeable Φ . Because excitation loop inductance is big, electric time constant is big, fast sex differs timing, rotate speed can be increased up by rated rotate speed only. Normal > (3) couplet adjustment resistor is strung together in armature loop. Rotate speed can be moved only low, cupreous bad news is big, wasteful. Dc servo electric machinery is used normally pressure regulating timing. (2) electric machinery of servo of big inertia dc calls servo of wide timing dc electric machinery again. 1. Means of structural characteristic excitation is magneto. Structural characteristic is main around raise torque coefficient, increase output moment of force. Φ of torque coefficient KT=CM, CM=pN/2 π A. Use high-powered magnetic data. Produce Φ of strong magnetic field, and the stability of magnetism function is good. Raise the cut area of the groovy number on rotor and chamfer, increase (N) number of armature winding total conductor, (P) extremely logarithm. Use form of single wave winding, reduce logarithm of shunt-wound spur track (A) . Increase extremely logarithm, still can reduce armature inductance, reduce the mechanical constant of electric machinery and electric constant thereby, raise response fast sex. Raise the meaning of torsion to depend on: Low speed torsion is big, overload capability is strong. Inertia is big, output torsion is big, but direct drive is laden, beardless and mechanical decelerate. Timing range is wide, use data of high grade brush, increase the interface of brush to accumulate, increase the stiffness of axis and bearing, thereby better settlement the problem of high speed inverting, raised the working rate of electric machinery. Increase rotor chamfer number and commutator segment number, make alveolar distributing even, reduced the wave motion of torsion, electric machinery still can move smoothly when low speed. Outfit low ripple is measured inside fast dynamo, still but inside outfit position detecting element. Thermal capacity is large, can work for long below natural cooling condition or work below overload condition. 2. Character of working character job is mixed by a few parameter restriction of characteristic curve institute. Speed limit line: Do not produce the line of rotate speed upper limit of mechanical failure. Calorific bounds line: When moving continuously, temperature reachs the limit that insulation place allows. Inverting bounds line: Good inverting / line of instantaneous inverting bounds: Demagnetization bounds line: Torsion moves at this line greatly, can appear irreclaimable demagnetization phenomenon. 5 afore-mentioned lines, electric machinery moving cent is 3 work area: Area Ⅰ : Successive work area; Area Ⅱ : Knock off makes a division between; Area Ⅲ : Brief work area. (3) the silicon controlled rectifier of dc servo electric machinery (brilliant brake is in charge of) timing system silicon controlled rectifier, working character is similar to diode, add just may guiding to voltage, and guide still depended on spark whether to have spark pulse. When alternating current action at silicon controlled rectifier, be in half weeks, try to spark pulse, guide, electric current sheds overload, lose half weeks, silicon controlled rectifier ends, accordingly, only dc is passed on load, and, the change sparks horn, the average volts d.c. on changeable load. Load is perceptual load (electric machinery) , should spark when horn is less than 90 ° , job of silicon controlled rectifier is in rectification condition, the job when be more than 190 ° is in inversion condition. The system of timing of silicon controlled rectifier of dc servo electric machinery sheds timing continuously by silicon controlled rectifier advocate loop and control loop composition: Advocate loop uses three-phase bridge-type to turn over paralell connection not to have circumfluent and reversible loop more (graph 4-12) , offer for electric machinery but pressure regulating direct current source (bridge-type loop commutate) , and the positive and negative that realizes electric machinery turns (two groups when turn over paralell connection) with fast inverting (inversion) . Control loop is mixed for loop of double-loop of speed, electric current touch hair circuit to comprise (graph 4-11) . Touch hair circuit to give priority to accuse loop to offer spark pulse, control sparks horn. Normal > (4) the system of PWM of abbreviation of system of pulse width timing of dc servo electric machinery, it is to use the high-power transistor with switch taller frequency to regard switch as component, the constant voltage direct current source after rectification, changeover becomes amplitude changeless, but pulse width (duration) adjustable high frequency and rectangular wave, give the armature of servo electric machinery power supply. Change pulse width, with respect to the average voltage that can change armature loop, be opposite thereby electric machinery timing. The pulse of dc servo electric machinery moves principle of wide timing system to be like graph 4-13. Main circuit is PWM of amplifier of wide modulation of transistor arteries and veins. Control circuit includes: Speed controls loop, electric current to dominate circuit of wide modulation of loop and arteries and veins. The Uc of speed instruction volts d.c. that after via speed operating ring and electric current operating ring adjustment alternates, outputs, circuit of wide modulation of it and trigonometry wave passages through which vital energy circulates, modulation hind gets moving broad pulse series, as control signal carries PWM each base of relevant transistor, make move wide pulse to be able to magnify, become the input voltage of armature of dc servo electric machinery. 1. Task of circuit of pulse width modulation: rate instruction voltage signal is changed into pulse cycle fixed, and the pulse voltage that width can dictate by speed the size adjustment of voltage signal changes. Because pulse is periodic fixed, the change of pulse width will make the average voltage of pulse voltage is changed, be changed along with instruction voltage namely and change. After classics PWM magnifies, the voltage that inputs armature also follows a change, achieve the goal of timing thereby. Principle: Circuit of wide modulation of arteries and veins is comprised by trigonometry wave generator, comparator and pulse alloter. Graph 4-14. When trigonometry wave (amplitude and frequency are changeless) with Uc of speed instruction voltage (dc) after inputting comparator, be like the polarity that its mix to be negative, output positive electricity to press square wave, for when, output presses square wave for negaive electricity. If pursue, in 0-t1, trigonometry wave loses amplitude to be more than Uc, polarity is negative, output presses square wave for positive electricity; When T1-t4, polarity is negative, output is negative square wave. Such. Dc changeover is bipolar pulse. When 1 change, pulse width as the change. The pulse signal that comparator outputs, via pulse alloter cent is signal of wide modulation of arteries and veins of quadruplet of Ub1, Ub4, Ub2, Ub3. Regard PWM as the control signal of each transistor base. When Uc from negative increase when the pulse width of Ub1, Ub4 increases, the pulse width of Ub2, Ub3 is reduced. Uc is zero hour, losing pulse width equal. 2. Transistor pulse amplifier pursues 4-15. H form is bipolar wide amplifier of arteries and veins. Add circuit of follow on current to comprise by circuit of bridge of double transistor switch. Normal >T1 and T4 are a group, t2 and T3 are a group. With group two dynatron guide at the same time connect or close. Two groups are connected alternately. It is when Uc when of Ub1, Ub4 pulse width is more than negative pulse width, of Ub2, Ub3 pulse width is less than negative pulse width. Armature adds integrity to shed voltage, electric current sheds A from B, electric machinery is turning, conversely, uc is when losing, electric machinery inverts. The absolute value of Uc is greater, the average tension that is increased on armature is taller, rotate speed is higher. Uc is zero hour, average voltage is 0, electric machinery stops. 4, electric machinery of servo of communication of wide timing of arteries and veins and Normal > dc servo has good timing character and torsion character, but structure complex, production cost tall, volume is large, and brush wears away easily, commutator can produce scintilla, it is its are used be restricted. Normal > communication electric machinery does not have the defect on the structure such as brush and commutator. And, mix as technology of parts of an apparatus of new-style power switch, special integrated circuit, computer the development that controls algorithm to wait, make the timing of drive of servo of alternating current machine characteristic the requirement that can get used to servo of feed of numerical control machine tool more. (one) permanent magnetism synchronism communicates Normal > communication induction simple, capacity big, price is low, use at commonly advocate athletic drive. Normal > servo drive uses communication synchronism electric machinery. Normal > permanent magnetism communicates electric machinery structure. (2) the: of rotate speed formula that communicates the frequency control basis of servo electric machinery to communicate electric machinery? Enlighten paper melt location of of raw meat or fish of admonish of Liang of male of Jian black wrings sword Ha Ormal >1) change pole logarithm (P) , can realize step speed changing only; Normal >2) control slippery difference is led (S) , ability of communication asynchronous electric machinery comes true, and timing range is narrow, control not easily; Normal >3) change communication frequency (F) , can implement the stepless speed regulation of wide range, and rotate speed and frequency become direct ratio; Normal > communication servo uses frequency control. Normal > has the phase voltage formula of alternating current machine: , when frequency F is elevatory, if the phase voltage of the input is changeless, criterion Φ of air gap magnetic flux is reduced; Normal > again by the torsion formula of alternating current machine: , Φ is reduced, of electric machinery rotor faradic also reduce accordingly, electric machinery outputs torsion to drop. Additional, frequency F is reduced, Φ of air gap magnetic flux will increase, this can bring about magnetic circuit saturation again, magnetizing current rises, iron cost leap, power element drops. For this: Normal > frequency control, need changes the phase voltage of stator at the same time, be close to in order to maintain Φ changeless, make output torsion adjacent also and changeless (constant torsion) . Visible, the crucial question that communicates frequency control of servo electric machinery is to should obtain the alternating current source with pressure regulating frequency modulation. Frequency modulation is pressure regulating power source uses communication normally----Dc----The commutation circuit of communication comes true, the main component of this kind of circuit is inverter of three-phase electric current. Graph 4-17 is inverter of three-phase of transistor of the tension that uses extensively at present power advocate loop principle graph. Communication---Dc: Diode works galvanic way, obtain constant volts d.c. Ud; Normal > flows continuously---Communication: The inverter of wide modulation of three-phase arteries and veins that comprises by V1 of component of power transistor switch, V4, V3, V6, V5, V2, obtain the three-phase alternating voltage with frequency and adjustable amplitude. Normal > by wide modulator of arteries and veins of wave of sine of wave of 3 high-speed triangle, of the switch element that controls inverter by definite pattern connect, obtain 3 groups to wait in the output end of inverter thereby, equidistant, but differ wide rectangular pulse, come approximate equivalent at three-phase sine voltage. Normal > triangle wave is shown like graph 4-18 place. Normal >VT is ET for amplitude, what frequency is FT is bipolar trigonometry wave, call carrier wave. VS is sine wave, call control wave, the each photograph of inverter has control all the way wave, amplitude is ES together, frequency is FS together, phasic differ 120 ° . The amplitude of control wave and phasic it is adjustable. According to the node of trigonometry wave and sine wave, can produce to be in TS (=1/fS) the amplitude inside cycle is ES etc, equidistant, but the pulse that width shows sine to distributing. Normal > uses each photograph goes controlling advocate the fluctuation with inphase loop the base of two transistor (like A photograph, tall n controls V1, low n controls V4) , result, the is similar to control pulse series shift that the frequency that outputs end to obtained power of a group of classics to magnify in inverter is FS is broad rectangular pulse, its equivalent is the sine voltage of FS or electric current at frequency. Its base wave voltage amplitude is: Normal > by go up type. U, E is changeless, the amplitude of the sine voltage that through changing the amplitude E of control wave to be able to adjust inverter outputs----Implementation is pressure regulating. The frequency of the frequency that outputs voltage as a result of inverter and control wave is same, same, the frequency that changes control wave can realize frequency modulation. CNC Milling