CN101515776B - Braking controlling method for point-to-point position servo of induction machine - Google Patents

Abstract

The invention discloses a braking controlling method for the point-to-point position servo of the induction machine. The energy consumption braking servo phase trajectory of the induction machine runs commonly along the optimum switched-line, which is the time price suboptimum braking controlling method, the braking controlling method is that: the induction machine runs at the predetermined maximum speed according to the error amount deltaX of the initial displacement coordinate X2 and the target displacement coordinate X<x> of the controlled moving object, when the induction machine reach the displacement coordinate X1 of control amount state switch shifting, the Bang-Bang controller in the braking controlling system sends out a braking signal, the power inverter outputs a variable stator braking current with the amount in the certain function relation with the rotor rotating speed omega[r], so that the energy consumption braking phase trajectory of the induction machine runs along the optimum switched-line, accordingly the time price of the target displacement coordinate X<x> is optimal, and the variable current braking energy consumption is less, thus having theory innovation and practical value.

Description

The brake control method that is used for the point-to-point position servo of induction machine

Technical field

The present invention relates to elaborate servo control technology field, relate in particular to a kind of brake control method that is used for the efficient point-to-point position servo of induction machine fast precise.

Background technology

Point-to-point location comes down to the position servo servomechanism according to position closed loop feedback signal, the control of employing digital technology, and its basic task is to realize that actuator follows the tracks of as far as possible fast and accurately to position command.Current, servo servomechanism just develops towards high accuracy, response direction fast, intelligent, low energy consumption, and method of servo-controlling has been proposed more and more higher requirement.Induction machine is big because of its capacity, reliability is high, be applicable to servo very widely field, each department that spreads all over national economy, positioning control as lathe in the mechanical processing process, require welding head can align weld seam exactly in the metallurgical industry to realize the precision welding of seamed steel pipe, the pin position control of textile industry high speed flat seam machine etc.Dynamic braking is a kind of common control method of induction machine servo-positioning, promptly passes to direct current in stator winding, thereby produces a changeless magnetic field, when rotor continues rotation owing to inertia, its winding cuts this magnetic field, produces the torque opposite with rotary speed direction, i.e. brake torque.The advantage of this method is fast and accurate for positioning and non-overshoot, special-purpose brake unit etc. need be installed.But this brake control method is if pass to the constant braking electric current to motor stator in position fixing process, then power consumption is bigger, and this is a big shortcoming.

The control method of fast precise position servo is based on the Bang-Bang optimal theoretical, as shown in Figure 2, establishes the motion object at displacement coordinate x ₁Point intersects at the A point on the optimized switch line 1, and speed is (ω _r) _A, this moment, the controlled quentity controlled variable status switch switched to braking by electronic, and stalling current is got the constant maximum value the inverter margin of safety under, and under the ideal conditions, the motion object (is displacement of targets coordinate x as if converging to the origin of coordinates along optimized switch line 1 non-overshoot ^*), time cost optimum then.But further analyze as can be known, different with direct current machine, induction machine is under the effect of constant energy consumption stalling current, and its operation phase path is to converge on the origin of coordinates, curve A T along optimized switch line bunch (for example line bunch 1～4) _mO is obviously big than curve A O time cost, though and stalling current constant, braking moment is with speed omega _rNonlinear change, maximum only appear at T _mA bit.For shortening the braking convergence time, need to strengthen the constant braking electric current of stator, but in actual applications, the stator current maximum will be subjected to many effects limit, as inverter, motor overheating, inverter overcurrent etc. are from improving the angle of retardation efficiency, strengthening stalling current simply to exchange the optimization of time cost for, is inconsiderable equally.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, a kind of brake control method that is used for the efficient point-to-point position servo of induction machine fast precise is provided.

The objective of the invention is to be achieved through the following technical solutions:

The brake control method of the point-to-point position servo of a kind of induction machine, braking control system mainly is made of digital processing unit, fuzzy controller, Bang-Bang controller, phase sequence generator, PWM generator and power inverter, and the Bang-Bang controller comprises the controlled quentity controlled variable status switch; This method may further comprise the steps:

(1) digital processing unit receive enabling signal make the controlled motion object with certain given maximal rate to displacement of targets coordinate x ^*Operation;

(2) the displacement coordinate value x of the de-fuzzy value decision controlled quentity controlled variable status switch switching of fuzzy controller output ₁, current real-time rotor speed omega _rA variable input as fuzzy controller;

(3) digital processing unit detects the controlled motion object and arrives the displacement coordinate x that the controlled quentity controlled variable status switch switches ₁The time, exciting Bang-Bang controller output brake signal, the phase sequence generator enters the dynamic braking phase sequence;

(4) digital processing unit calculates the parabolical switching line coefficient value that Bang-Bang controller output dynamic braking signal initial time A is ordered $P_A=\frac{{\left({\mathrm{\&omega;}}_r\right)}_A}{a{\left({\mathrm{\&omega;}}_r\right)}_A-\mathrm{<figure-callout\; id="2"\; label="b\; I\; s"\; filenames="H2009100967841E00012.png"\; state="\{\{state\}\}">b</figure-callout>}{I}_s^{}{}_2^{}},$ Wherein, I _sBe stator system streaming current, (ω _r) _ABe this real-time spinner velocity constantly, for given induction machine, a, b are definite value;

(5) in next closed-loop adjustment in the cycle, digital processing unit detects new ω _r, order this moment $P=\frac{{\mathrm{\&omega;}}_r}{a{\mathrm{\&omega;}}_r-b{I}_{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="H2009100967841E00012.png"\; state="\{\{state\}\}">s</figure-callout>}}^2}=P_A,$ The digital processing unit required stator system streaming current I of this regulating cycle that seizes back confiscated property out _s, I _sAfter the digital processing unit mark is changed, to stator system streaming current reference quantity I _s ^*Compose new value; Gather I simultaneously in real time _s, to I _s ^*Revise, make actual P=P _AThe pulsewidth of PWM generator is subjected to I _s ^*The stator system streaming current I that power inverter is exported is regulated in modulation automatically _sSize.

The invention has the beneficial effects as follows:

1. control is all finished by digital processing unit, does not additionally increase the hardware detection cost.

2. overcome in the induction machine tradition Constant Direct Current dynamic braking process phase path and bunch converged to the shortcoming that origin of coordinates required time is long, energy loss is big along the optimized switch line, improved retardation efficiency, meet environmental protection and energy saving, for the efficient position servo of fast precise has found a new effective control method.

3. both guarantee positioning accuracy, and can improve the rapidity and the retardation efficiency of location again.

Description of drawings

Fig. 1 is the structured flowchart of braking control system;

Fig. 2 is that the present invention brakes phase path switching line schematic diagram.

Embodiment

Describe the present invention below with reference to the accompanying drawings in detail, it is more obvious that purpose of the present invention and effect will become.

Core of the present invention is that the controlled motion object arrives the displacement coordinate x that the controlled quentity controlled variable status switch switches ₁The time, braking control system is carried out braking to induction machine, output size and rotor speed ω in each closed-loop adjustment cycle _rThe variable stator stalling current I that keeps certain functional relation _s, induction machine dynamic braking phase path being avoided along optimized switch line bunch and converged to the origin of coordinates along certain bar optimized switch line (is displacement of targets coordinate x ^*), referring to Fig. 2, thereby precise high-efficiency is finished servo-positioning in the shortest time.Specific implementation of the present invention is undertaken by following induction machine dynamic braking phase path equation:

$\mathrm{\&Delta;x}=\frac{{\mathrm{\&omega;}}_r}{a{\mathrm{\&omega;}}_r-b{I}_s^2}{\left({\mathrm{\&omega;}}_r\right)}^2---\left(1\right)$

A=(2p wherein _n/ T _L)/J, $b=\left(6x_m^2{R}_r^{\&prime;}\right)/{(x_m+x_r^{\&prime;})}^2,$ p _n: motor number of pole-pairs, T _L: load torque, J: load inertia, x _m: the reactance of excitation phase, x ' _r: the reactance of rotor phase, R ' _r: the rotor phase resistance.For given induction machine, a, b are definite value.Make in the formula (1) $P=\frac{{\mathrm{\&omega;}}_r}{a{\mathrm{\&omega;}}_r-\mathrm{<figure-callout\; id="2"\; label="b\; I\; s"\; filenames="H2009100967841E00012.png"\; state="\{\{state\}\}">b</figure-callout>}{I}_s^{}{}_2^{}},$ Be that P is the switching line coefficient of parabolical braking phase path, corresponding different P values can obtain the brake switch line bunch on Fig. 2 phase plane.

As shown in Figure 1, braking control system mainly is made of digital processing unit, fuzzy controller, Bang-Bang controller, phase sequence generator, PWM generator and power inverter, and the Bang-Bang controller comprises the controlled quentity controlled variable status switch.

As shown in Figure 2, the present invention's brake control method of being used for the point-to-point position servo of induction machine may further comprise the steps:

1, digital processing unit receive enabling signal make the controlled motion object with certain given maximal rate to displacement of targets coordinate x ^*Operation.

The initial displacement coordinate x of controlled motion object ₂With displacement of targets coordinate x ^*Error amount Δ x more little, the maximal rate of permission is then low more, vice versa.When Δ x was higher or lower than certain value, the maximal rate of permission is amplitude limit up and down.

2, the displacement coordinate value x of the de-fuzzy value decision controlled quentity controlled variable status switch switching of fuzzy controller output ₁, current real-time rotor speed omega _rA variable input as fuzzy controller.

Adopt fuzzy controller to find the solution x ₁, the software and hardware resources occupancy is low, method is succinct, overshoot is little, the influence of strong robustness, non-linear factor is little.Corresponding fuzzy implication relation is ω _rBig more, x ₁More little.

3, digital processing unit detects the controlled motion object and arrives the displacement coordinate x that the controlled quentity controlled variable status switch switches ₁The time, exciting Bang-Bang controller output brake signal, the phase sequence generator enters the dynamic braking phase sequence.

The A point is and excites Bang-Bang controller output brake signal working point constantly among Fig. 2.Phase plane ω _rOn-the x, induction machine begins to enter the dynamic braking phase path.

4, digital processing unit calculates the parabolical switching line coefficient value that Bang-Bang controller output dynamic braking signal initial time A is ordered $P_A=\frac{{\left({\mathrm{\&omega;}}_r\right)}_A}{a{\left({\mathrm{\&omega;}}_r\right)}_A-\mathrm{<figure-callout\; id="2"\; label="b\; I\; s"\; filenames="H2009100967841E00012.png"\; state="\{\{state\}\}">b</figure-callout>}{I}_s^{}{}_2^{}},$ Wherein, I _sBe stator system streaming current, (ω _r) _ABe this real-time spinner velocity constantly, for given induction machine, a, b are definite value.

Stalling current I _sInitial value is taken all factors into consideration inverter and induction machine allowance power, gets maximum, again according to the detected (ω of A point moment digital processing unit _r) _A, the optimized switch line of expectation is definite thereupon, i.e. optimized switch line 1 among Fig. 2.

5. in next closed-loop adjustment in the cycle, digital processing unit detects new ω _r, order this moment $P=\frac{{\mathrm{\&omega;}}_r}{a{\mathrm{\&omega;}}_r-b{I}_{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="H2009100967841E00012.png"\; state="\{\{state\}\}">s</figure-callout>}}^2}=P_A,$ The digital processing unit required stator system streaming current I of this regulating cycle that seizes back confiscated property out _s, I _sAfter the digital processing unit mark is changed, to the stator system streaming current reference quantity I in the software _s ^*Compose new value; Gather I simultaneously in real time _s, to I _s ^*Revise, make actual P=P _AThe pulsewidth of PWM generator is subjected to I _s ^*The stator system streaming current I that power inverter is exported is regulated in modulation automatically _sSize.

In the whole dynamic braking convergence process, because of ω _rReduce gradually, if stator system streaming current I _sConstant, then parabolical switching line FACTOR P changes thereupon, and braking procedure will (be not P along the P initial value _ABe worth) determined optimized switch line convergence, but, increased time cost and retarding loss along bunch convergence (seeing the dotted line among Fig. 2) of optimized switch line.Obviously, be certain constant as long as keep P, even stator current I _s ²With rotor speed ω _rRatio certain, then induction machine dynamic braking process will converge to initial point, the time cost optimum along the determined optimized switch line of P initial value.In the actual location process, the control of factor word processor discretization, stator current I _sWith rotor speed ω _rIt is many more to regulate number of times, promptly the closed-loop adjustment cycle short more, then dynamic braking phase path is just approached the optimized switch line more, time cost is also just more little.Further analyze $P=\frac{{\mathrm{\&omega;}}_r}{a{\mathrm{\&omega;}}_r-b{I}_s^2}$ As can be known, with the carrying out of braking, ω _rMore and more littler, then required I _sAlso more little, certainly will improve retardation efficiency.

Claims (1)

1. the brake control method of the point-to-point position servo of induction machine, braking control system mainly is made of digital processing unit, fuzzy controller, Bang-Bang controller, phase sequence generator, PWM generator and power inverter, and the Bang-Bang controller comprises the controlled quentity controlled variable status switch; It is characterized in that this method may further comprise the steps:

(1) digital processing unit receives enabling signal the controlled motion object is moved to displacement of targets coordinate x* with certain given maximal rate;

(2) the displacement coordinate value x of the de-fuzzy value decision controlled quentity controlled variable status switch switching of fuzzy controller output ₁, current real-time rotor speed omega _rA variable input as fuzzy controller;

(3) digital processing unit detects the controlled motion object and arrives the displacement coordinate x that the controlled quentity controlled variable status switch switches ₁The time, exciting Bang-Bang controller output brake signal, the phase sequence generator enters the dynamic braking phase sequence;

(4) digital processing unit calculates the parabolical switching line coefficient value that Bang-Bang controller output dynamic braking signal initial time A is ordered

Wherein, I _sBe stator system streaming current, (ω _r) _ABe this real-time spinner velocity constantly, for given induction machine, a, b are definite value;

(5) in next closed-loop adjustment in the cycle, digital processing unit detects new ω _r, make the switching line coefficient of the braking of parabolical this moment phase path

The digital processing unit required stator system streaming current I of this regulating cycle that seizes back confiscated property out _s, I _sAfter the digital processing unit mark is changed, to stator system streaming current reference quantity I _S*Compose new value; Gather I simultaneously in real time _s, to I _s ^*Revise, make actual P=P _AThe pulsewidth of PWM generator is subjected to I _s ^*The stator system streaming current I that power inverter is exported is regulated in modulation automatically _sSize.

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