Transducer is basic structure and control brief introduction

The basic structure transducer of 1 transducer is a labour frequency power source (the alternating current source that 50Hz or 60Hz) commutation become all sorts of frequency, in order to realize the facility that the gearshift of electric machinery runs, control circuit to finish the control to main circuit among them, rectification circuit becomes alternating current commutation dc, shed intermediate circuit to have flowing filter wave to the output of rectification circuit continuously, inversion circuit goes against dc again become alternating current. For the transducer that to be like vector to control transducer needs a large number of operation this kind, still need to undertake torsion calculative sometimes CPU and a few corresponding circuit. 1.

The classifies transducer classification method of 2 transducer has a variety of, according to main circuit working way is classified, can divide transducer of the profiling that it is report and transducer of electric flow pattern; According to switch means classification, can divide for PAM control transducer, PWM controls transducer and PWM of tall carrier frequency to control transducer; According to working principle classification, can divide control transducer for V/f, turn transducer of poor frequency control and vector control transducer; According to utility classification, can divide wait for general transducer, high-powered special transducer, high frequency transducer, single-phase transducer and three-phase transducer. The commonly used control means 　 in 2 transducer 2.

The means of blame intelligence control that means of control of 1 blame intelligence uses in communicating transducer has V/f cooperative control, turn poor frequency control, vector control, direct torsion control. (Control of V/f of 1)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. (2) turns poor frequency control turns the control means that poor frequency control is torsion of a kind of direct control, it is to be on V/f pilot foundation, according to the power source frequency of the correspondence of actual rotate speed that knows asynchronous electromotor, adjust according to hoping gotten torsion comes the output frequency of transducer, output torsion with respect to what can make electromotor has correspondence. This kind controls fashion, in controlling a system need installs speed sensor, still add sometimes have voltaic feedback, undertake controlling to frequency and electric current, accordingly, this is means of a kind of closed-loop control, can make transducer has good stability, add decelerate and load to change to express have good response characteristic. (Control of vector of 3) vector control is the bulk that controls electromotor stator electric current through vector coordinate circuit is mixed phasic, medium excitation electric current and torsion electric current are fastened in order to achieve to undertake controlling respectively in D, Q, 0 reference axis to electromotor, achieve the goal that controls electromotor torsion then. Through dominating the action order of each vector and time and the effect time of 0 vector, can form all sorts of PWM wave again, achieve all sorts of different control goals. Form the PWM wave with switch least frequency for example in order to reduce switch loss. The vector control means that uses actually in transducer at present basically has be based on turn means of control of vector of poor frequency pilot and the vector that do not have speed sensor control fashion two kinds. Be based on turn the vector control means of poor frequency and turn means of poor frequency control decides constant character bothly to agree, but be based on turn the vector control of poor frequency alternates through coordinate even of pair of electromotor stator electric current phasic undertake controlling, made contented and certain condition, pass the wave motion in crossing a process in order to eliminate torsion electric current. Accordingly, be based on turn the vector control means of poor frequency differs frequency to control means to be able to get very big improvement in output character respect than turning. But, means of this kind of control attributes closed-loop control kind, need installs speed sensor on electromotor, accordingly, applied limits is restricted. Having speed sensor vector to control is to pass coordinate to alternate processing parts to undertake controlling to excitation electric current and torsion electric current, the voltage that goes up through controlling electromotor stator winding next, electric current differentiates the end that rotate speed dominates excitation electric current and torsion electric current with achieving. Range of timing of means of this kind of control is wide, the torsion that start is big, the job is reliable, the operation is convenient, but calculation is more complex, need special processor to have consideration commonly, accordingly, real time sex is not too ideal, control precision is calculated the influence of precision. (4) direct torsion controls direct torsion is the concept that uses dimensional vector coordinate, the mathematical model of AC motor is analysed below stator coordinate department, control the linkage of electromotor and torsion, through detecting stator resistance achieves the goal of observation stator linkage, because of this leave out the complex commutation calculation such as vector control, the system is intuitionistic, compact, computational speed and precision control means to rise somewhat than vector. Although be below the condition of open loop, also can output the rated torsion of 100% , move to procrastinating more have bear to balance a function. (5) best control is best what control is applying a basis mediumly actually to ask is different and differ somewhat, can ask to undertake the optimization of individual parameter to certain control according to best pilot theory. It is for example in the control application of high-pressured transducer, successful adoption time section control and phasic translation control two kinds of strategy, the voltage that falls in order to realize certain condition is best and undee. (Intelligence of 6) other blame controls means to be in actual application, still a few is not intelligence to control means to be able to come true in the control of transducer, change from adaptive control, slippery model for example the structural control, control that differ frequency, circumfluent control, frequency control. 2.

Means of control of intelligence of means of 2 intelligence control basically has control of system of nerve network control, ambiguous control, expert, study to wait. There is the model of a few successes in intelligence is being used to control means to be in specific applying in the control in transducer. (1) nerve network controls nerve network to control means application to be in the control of transducer, it is to undertake complex system is controlled comparative commonly, understand to systematic model at this moment very little, accordingly nerve network should fulfil the function that the system differentiates already, want to undertake controlling again. And means of nerve network control can control many transducer at the same time, because this is when many transducer cascade,undertake controlling comparative suitable. But too much algorithmic perhaps too complex metropolis is in the number of plies of nerve network many real difficulty are brought in specific applying. (2) faintness controls faintness to control algorithm to be used at controlling the voltage of transducer and frequency, make litre of fast time of electromotor get controlling, rise in order to avoid fast be opposite too quickly the influence of electric machinery service life and litre fast work efficiency of too slow influence. Ambiguous pilot key depends on talking region, subject degree and of ambiguous level differentiate, means of this kind of control applies to the control system that inputs only output more especially. (System of expert of 3) expert system is to use alleged " expert " experience undertakes pilot controls fashion one kind, accordingly, an expert warehouse should be built commonly in expert system, deposit certain expert information, have inferential mechanism even additionally, seek ideal control outcome in order to facilitate according to foregone information. The design of expert library and inferential mechanism is to be weighed particularly want, the relation is worn expert system pilot actors or actress bad. Applied expert system can control the voltage of transducer already, can control its electric current again. (Control of study of 4) study control basically is the input that is used at repeatability, and regular PWM signal (for example central modulation PWM) satisfies this requirement fitly, because this learns,control also can be used in the control of transducer. Study control does not need to know too much system news, but need 1~2 study is periodic, because this is fast the gender is opposite poorer, and, study needs to realize lead link sometimes in pilot algorithm, this uses imitate parts of an apparatus cannot come true, in the meantime, study controls the issue that still involves a stability, special attention wants when application. 3 transducer pilot looks into the development that waits for new and high technology as network of technology of electric power electron, microelectronics technology, computer, the control means of transducer will develop to the following respects henceforth. (The implementation of transducer of 1) number control now, the control means of transducer can realize more complex operation with digital processor, transducer digitlization will be an important development way, undertake transducer digitlization basically uses sheet at present piece machine MCS51 or 80C196MC, auxiliary wait with SLE4520 or EPLD LCD will achieve more perfect control performance. (The control way with a variety of single union that dominate means is having 2) respective actor defect, do not have " all-purpose " control means, the circumstance is controlled in some, need rises tie of kind of a few control, control study control and nerve network photograph union for example, be united in wedlock from adaptive control and ambiguous control photograph, direct torsion control and photograph of nerve network control are united in wedlock, perhaps say for " mixed control " , such learning from others's strong points to offset one's weakness, dominate the result will better. (3) long-range pilot achieves the progress of computer network, make " if skyline veries close " , relying on computer network to undertake be controllinged remotely to transducer also is direction of a development. Undertake be controllinged remotely to transducer through RS485 interface and agreement of a few networks, do not agree with in some so the situation that the mankind has field work, OK also very easy implementation dominates an end. (4) green transducer puts forward as what can develop the strategy continuously, the protection to the environment more and more get the attention of people. The Gao Cixie wave that transducer generates can bring pollution to electrified wire netting, the noise when reducing transducer to work and the dependability that enhance its to work, security waits these problems a moment, try to be solved through taking right control kind, the design gives green transducer. The control means of transducer of 4 last words is a problem that deserves research, support devotes oneself to the joint efforts of a man of insight of this job, make homebred transducer moves toward world market at an early date and make top-ranking product. CNC Milling