DE1263147C2 - PI-CONTROLLER FOR ADAPTING THE CONTROLLER TIME BEHAVIOR TO THE TIME BEHAVIOR OF THE REGULATED SYSTEM - Google Patents

Description

stretch peculiar time constants Γ as a function of which changes proportionally with the time constant. the

of their initial size χ. The for in F i g. 2 shown controller arrangement acts like a

the time constant that is decisive for the controlled system has a PI controller, the reset time of which is proportional to the

So a large controlled system time constant T is changed for small values and a variable controlled system time constant T for large ones

Values of the controlled variable a relatively small value to 5, whereby its integral component is unaffected

and would be z. B. for a power-controlled heating remains. This is an automatic compensation of the

emitters characteristic. operating point-dependent time constants for all

F i g. 2 shows the control device according to the invention, ie. H. the entire work area of the device for a control device symbolized in the form of a block 1 is possible. The accuracy of the Re control system. Most of the time the control loop is still defective if the two are not impaired Further, but not shown elements with memory function generators 4 and S do not exactly agree be present, which coincide, because the integral controller 3 deviate from each rule with the controlled system 1 in the event of a mismatch to chung finally corrects.

unwanted control oscillations give rise to F i g. 3 shows a device-related embodiment. In the block symbol 1 is the time game of the control device according to the invention. For run of the controlled system output variable m dependent - corresponding elements have been given the reference symbols is taken over from a sudden change in the input from FIG. The integral controller 3 is size shown. through a capacitive negative feedback direct current

Depending on the size of the output value, ie implemented at the amplifier 9, with the variable T ₁ characteristic of its dynamic behavior depending on the respective operating point, resulting from the transition functions designated by the promit α to c, resulting in the input resistance R ' _o and the opposite, the transition function α is fixed at a smallest coupling capacitance C. The function and the transition function c are established in the case of a largest generator 4 and S in the illustrated considered value of χ and all the transfer example from two direct current amplifiers 10 output functions strive towards the same final value. The »5 and 11, which are fed back in the same way, frequency response of this controlled system therefore has the all and the gain of which results as a quotient

S ^{ei er} 1C ^ ^{es Ewe} i ' ^s effective negative feedback resistance R _g and the input resistance _{R e} . Parallel to

F _{5 days} gg _e

1 + pT _{x) 30 the resistor labeled R ' _g are further negative feedback paths via the resistors 12

where T, _{tl have} the course shown in Fig. 1 and 13 are provided, each in series with

may. Diodes 14 and IS to different ones, the diodes in

The controlled variable χ is applied in the usual way with voltages applied to the blocking direction.

Setpoint w compared in a mixing point 2 and the 35 are closed, those of a designated with - U

Target-actual value difference can be derived from the input of an integral DC voltage source,

Regulator 3 is supplied, which has a frequency response of When the input signal increases - χ the

Form JL may have. ^Di ° <* ^{en 14} _t ^{and 1} ^ successively permeable and

In this way, pTl ° switch the negative feedback

Both the controlled variable χ and the setpoint w 40 would be 12 and 13 parallel to the resistor R ' _{g, see above}

are via a function generator 4 and 5 each so that the gain factor of the amplifier 10 is

leads, which is increased as the P component in parallel to the integral manner. By appropriate choice

controller 3 (I-Antoil). the blocking force acting on diodes 14 and 15

The output signals of the function generators 4 voltages and, if necessary, by further, pre- and 5 are led to a mixing point 6 and are 45 additional areas containing voltage diodes there subtracted from each other so that the coupling paths can be those in the block symbols 4 passage 7 of the controlled system 1 with a variable and 5 of FIG. 2 function shown as desired which of the difference de- output will be approximated.

signals of the function generators 5 and 4, enlarged. The amplifier labeled 11 in FIG. 3 corresponds to the output signal of the integral controller 3 and corresponds completely to the speaking with regard to its wiring elements. In the block symbols of the function generator amplifiers 10, and with respect to the front gates 4 and S, their static characteristic curves representing voltage supplying voltage source + U are symmetrized, ie the course of their output variables A is constructed in tric format.

Dependence on their input variables E. These are instead of the negative feedback resistance R ' _g

Characteristic curves show the same course and are thus 55 additional parallel paths to the input resistance Re

chosen that z. B. in the function generator 4, the type of F i g. 3 assigned, then with the watchful

Relationship applies sender input variable the gain factor stu-

A = kj (x) d χ , enlarged by a window. If you see these parallel paths in both the input and the negative feedback

where k is a constant and / _(v) the resistance shown in FIG. 1, then functions for the time constant Γ can be calculated in this way. based on various functions, so that the invention

The function generators can therefore not be restricted to a controlled system whose

Amplifiers are understood, the gain of which time constant according to the type of FIG. 1 runs.

1 sheet of drawings

Claims (2)

ι 2 of the two parts for adapting the regulator period claims: hallcns to the changing time behavior of the controlled system as a function of a control loop variable 1. PI controller, consisting of the parallel switch that can be changed automatically hung a P and an I component, with the 5 A PI controller of this type for regulating the degree of freshness starch is one of the two components for the apit temperature of steam generators after the controller time response has been adapted to the DT-AS 11 06 336 known. There, in order to adapt the changing time behavior of the controlled system, the readjustment can be changed automatically depending on the load-dependent and thus disturbance-dependent dependency of a control loop variable, characterized in that the P component is off when the proportionality remains constant two completely identical structural part changed, in that there is a measuring device for the th amplifiers, the output signals of which are a load-dependent variable, e.g. B. electromechanical can be subtracted from each other so that the adjustment of an amplifier (4) arranged in the input of the I channel only effects the actual value signal and the other resistance. An amplifier (5) which is different from the operating point is only dependent on the setpoint signal, ie is dependent on the rule added and that the characteristic curves of the two variable, changing time constants cannot be compensated for in the amplifier by the change function T = j (x) of the gel because the operating point of the controlled system time constants are essentially adapted to the controlled variable (x), which is independent of disturbance variables. gigen setpoint is closely coupled. Also would with that 2. PI controller according to claim!, Characterized 20 known PI controller with the adjustment of the by means of two function generators (4, 5) with each reset time to the same extent its integrating unit DC amplifier (10, 11), change in the time, since its proportional component remains constant. Negative feedback branches in series with resistance - This would have the consequence that the rise time changes, den (12, 13) by direct voltages so that z. B. the adjustment of a control deviation voltage diodes (14, IS) are arranged (Fig. 3). 25 with increasing enlargement of the normal route line incidents would slow down, so optimal operation would not be possible. The object of the invention is to provide a simple way of avoiding mechanical actuators gen, with which an operating point-dependent change in the controlled system time constants by means of a corresponding In control loops, changes in the reset time that can be stored cause delays in certain elements to be compensated for, without the control deviations being reduced. Control technology speed must be accepted.
If one speaks of such members as inertia, this object is achieved according to the invention by assigning them to their dynamic behavior that the P component is made up of two identical, structurally characteristic time constants. It is customary to have the th amplifiers, the output signals of which are subtracted from each other by the time constants given by the controlled system, of which one amplifier has to be compensated as far as possible, for example only from the actual value signal and the other amplifier through special lead elements or through the fact that 40 is only acted upon by the setpoint signal and the characteristic PI controller is used whose reset time lines of the two amplifiers corresponds to the change function of the time constants to be compensated. of the controlled system time constants as a function of There are now controlled systems whose inertia or whose are adapted to the controlled variable. This time constant, which is relevant to the arrangement, changes with the work, making it possible to change with an unchanged integral point. This is e.g. B. with most I exciter part an additional proportional part and flow control is the case where the quotient with the reset time of the PI controller in the same th of inductance and resistance of the exciter circuit way of the working point as the 6es given time constant with increasing excitation inertia of the controlled system. Btrom decreases as a result of iron saturation. For the optimal purpose, to simulate the operation of such a control loop, function generators would interrogate that the inertia compensating means apply which, in a further embodiment of the invention, continuously adapts its characteristic values to the changing changes in the setpoint and actual value branches similarly adjusted to time constants of the controlled system. built direct current amplifiers are arranged, where-It is to maintain a certain damping with the desired functions with non-linear degrees with working point-dependent change of the 55 negative feedback are realized, which from in series transfer coefficients of the controlled system in the Behar- with resistors and known by equation state, the Proportionality factor voltages biased diodes exist,
of the controller in terms of device technology with the reference variable The adjustment according to the invention proves to be of particular importance (W. Oppelt, "Small according to the device in the regulation of the Ab manual technical control processes", I960, p. . When using a PI controller, the operating point-dependent fluctuations in the time would, however, leave its reset time constant, so the radiator would be quite substantial that such an adjustment would take on the above-mentioned. This is because the emitted compensation is fundamentally unsuitable. Heat output roughly with the fourth power of In contrast, the invention shows a way to increase the radiator temperature. Solution to this problem. It relates to a PI controller, the invention is intended below with reference to the fi consisting of the parallel connection of a P and Guren are illustrated in more detail. In Fig. 1 is an I-component, where the degree of gain of a with f (x) the course of a certain control