The working principle of transducer and control means

75 ～ 400kW, working frequency is 0 ～ 400Hz, its main circuit is used hand in, straight, make circuit. Its controlled means to experience the following 4 generation. 2.

The wide modulation of sine arteries and veins of 1U/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. 2.

Vector of 2 voltage space (SVPWM) control fashion it is with three-phase weaveform whole generates the effect to be premise, with approaching the ideal circle of electric machinery air gap to rotate magnetic field contrail is a purpose, generate three-phase modulation weaveform, less than cuts polygon to approach round means to have pilot. Via after practice is used, be being improved somewhat again, introduce frequency compensation namely, can eliminate speed pilot error; Pass amplitude of feedback estimation linkage, remove the effect of resistor of the stator when low speed; closed circuit of output voltage, electric current, in order to increase dynamic precision and stability. But control circuit link is more, and the adjustment that did not introduce torsion, so systematic performance did not get fundamental improvement. 2.

3 vector are 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. 2.

4 direct torsion are controlled (DTC) means 1985, the DePenbrock of rash Er university taught Germany to put forward direct torsion to control frequency conversion technology first. This technology solved afore-mentioned vector pilot inadequacy greatly, and the construction of system with original control idea, concise palpability, good movement condition performance got developing quickly. Current, this technology applies successfully on drive of communication of high-power of tractive of electric power engine. Direct torsion control fastens next mathematical models that analyse AC motor in stator coordinate directly, control the linkage of electromotor and torsion. It does not need to be AC motor equivalent dc motive, consequently leave out vector change coming back changes a lot of medium complex calculation; It does not need to imitate the control of dc motive, also do not need the Ou that it is solution and simplify the mathematical model of AC motor. 2.

5 matrix type is handed in, handing in frequency conversion of control means VVVF, vector to control frequency conversion, direct torsion to control frequency conversion is to hand in, straight, one of making frequency conversion. Its are collective defect is power input factor low, harmonic electric current is big, dc road need is big store can capacitance, second birth energy cannot feedback again wire back net, cannot undertake 4 quadrant move namely. For this, matrix type is handed in, fall frequency conversion arise at the historic moment. Because matrix type is handed in, hand in frequency conversion leave out intermediate dc link, thereby leave out bulk big, price electroanalysises expensively capacitance. It can realize power factor to be L, input electric current is sine and can 4 quadrant move, power density of the system is big. This technology is current although have not mature, but still attracting numerous scholastic development to consider. Not be the indirect control electric current, quantity such as linkage character actually, serve as torsion directly however controlled the capacity will come true. Specific means is: -- control stator linkage introduces stator linkage observation implement, implementation does not have speed sensor means; -- identify automatically (ID) the model of electric machinery maths with mathematical support, identify automatically to electric machinery parameter; -- cipher out is worth saturation of corresponding stator impedance, mutual inductance, magnetism actually speed of linkage of the torsion with the actual cipher out such as element, inertia, stator, rotor undertakes real time is controlled; -- implementation Band, the Band that Band control presses linkage and torsion, Band control generates PWM signal, undertake controlling to inverter switch condition. Matrix type is handed in, hand in frequency conversion to have fast torsion to answer (<2ms) , very tall speed precision (2 ％ of ± , feedback without PG) , tall torsion precision (3 ％ of < ＋ ) ; Still have taller starting torsion and tall torsion precision at the same time, it is especially when low speed (when including 0 rate) , can output 150 ％ ～ 200 ％ torsion. CNC Milling