DE1255773B - Contactless AC regulator - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

G05b

G05f
German class: 21c-46/51

Number: 1255773

File number: S 57518 VIII b / 21c

Filing date: March 25, 1958

Opened on: December 7, 1967

Most of the purely electrical regulators work both in the input circuit and on the Actuator side with direct current. This is due in part to the fact that those on the plant side available components, such as excitation machines, DC motors, synchronous generators, magnetic amplifiers, Power converters, almost without exception, can be controlled with direct current. Furthermore, with DC regulators a stabilization of the control loop can easily be achieved by feedback with reactances.

For many control problems, however, the use of an AC regulator seems appropriate, be it: because the controlled variable or the control deviation occurs as alternating voltage, such as B. in voltage regulation a synchronous generator, or an AC voltage is required on the actuator side, such as this is the case, for example, with the speed sensor-controlled AC servo motor. Here it falls Error message as alternating voltage and is converted into an alternating voltage by a control amplifier Power to the auxiliary phase of the motor converted.

For the use of an AC regulator, which in the following is to be understood as a regulator, which works exclusively with alternating variables in the sphere of activity from the measuring location to the controller output, In addition to reasons that are due to the respective control system, there are also fundamental, specific technical control advantages. For example, there is the problem of zero point drift in the DC regulator (Drift) as well as the potential separation and impedance matching cause considerable difficulties. In the case of an alternating current regulator, on the other hand, drift cannot occur at all, impedance matching and electrical isolation can be easily achieved with the help of transformers.

In the case of AC regulators, there should now also be the possibility of dynamically adapting its transmission behavior to that of the regulator system, similarly as with direct current regulators, where it is known that a PD-IP- or IPD behavior or other transfer functions can be achieved.

For this purpose, an electromechanical alternating current controller has become known in which the controlled variable an alternating voltage amplifier in the form of a carrier-frequency amplitude-modulated by means of a resolver Input signal is supplied and the output of the AC amplifier via an AC motor is converted into a mechanical manipulated variable. To achieve the desired dynamic behavior became feedback contactless with this device, which in itself only acts proportionally AC regulator

Applicant:

Siemens Aktiengesellschaft, Berlin and Munich, Erlangen, Werner-von-Siemens-Str. 50

Named as inventor:

Dr.-Ing. Claus Keßler, Erlangen

or ballasts are provided, which resolver disk induction motor combination for converting mechanical rotations into stresses and vice versa. True, it can be done this way basically achieve any desired dynamic behavior of the AC regulator, the multiple However, the use of rotating transducers means a not inconsiderable effort and also requires maintenance of the moving parts.

Another known possibility for direct lead formation with purely electrical control loops Carrier frequency consists of passive AC filter networks in the input circuit of an AC voltage amplifier to be provided. However, only a so-called PD controller can be implemented with it, which is achieved by using of passive filter networks has considerable disadvantages, which in a highly load-dependent Frequency behavior as well as in the requirement of a highly constant carrier frequency, in particular when used in control loops with large time constants.

It is known in principle, based on the frequency response of a DC regulator of the desired dynamic Behavior, the frequency response of an AC regulator to which a carrier frequency is applied, whose envelope of its AC output signal should behave in the same way as the output signal of the corresponding direct current regulator, to be obtained in that the frequency response of the direct current regulator

ρ ¹ + ω ² Ip

replaced

the operator ρ by the operator

where ω is the carrier frequency. In this context there is the also known suggestion that the usual passive input and feedback networks in direct current regulators to achieve the desired dynamic behavior due to the aforementioned transposition rule in alternating current networks in the form of

709 707/443

3 4

To convert oscillating circles. A disadvantage of this analog can be a time constant element that is used in

Type of ac regulators the requirement for dc regulators the frequency response

a high quality of the oscillation γ used here

circles. _φ (ρ) = y ^ ---

The present invention has the task of 5 "·""' ^τ

the disadvantages of the known AC regulators to and after application of the transposition rule

Avoid by starting from the known trans- ding frequency response

Positioning regulation for the frequency response of a 2Vp

AC circuit this by means of negative feedback F (p) = -— - ^ —— ^ -

electronic amplifier in relatively simple switching ίο ρ ρ - \ - ω

processing arrangements is realized. The invention has been (F = gain, τ = time constant), by a

therefore draws on a contactless AC amplifier circuit according to FIG. 2 can be realized,

controller, which consists of a time constant amplifier 3 with

finally works with dormant means and the gain F ₃ and the time constant T ₃ , the

by the amplitudes of the alternating current quantities defi- 15 via an integrating amplifier 4 with the integrating

ned behavior is fed back to the dynamic behavior of a time T ₁ . The frequency response of the

DC regulator corresponds by in the frequency order according to F i g. 2 is with the ones specified there

passage of the DC regulator the operator / »through the designation

Operator is replaced. π ( _η \

* Ip ao t (ρ) =

According to the invention, to achieve an integral 2T ₃ P ² + 2p - \

Behavior, an integrating amplifier is provided, which has ⁴

another integrating amplifier is fed back. By comparing the coefficients of F (p) with

In a further embodiment of the invention, F '(p) results

Achieving a yield behavior the previously described 25 ^ 2 γ

level arrangement in the negative feedback loop of a line- V ₃ = V, T ₃ = - - τ and T ₄ = - ^ -.

aren amplifier arranged. ^{ω Τ}

In order to achieve a time constant behavior, a follow-up element that is used in the DC regulator

the inventive solution is a time con-frequency response
to provide a constant amplifier that has an integrating 30

amplifier is fed back. <p (p) = V- -γ-

A PD behavior can according to a further I -rρτ

Approach of the invention are achieved by _{hatj can be prepared by the in F} j _{g. 3} illustrated amplifier

that em linear amplifier is provided at whose _SCNA be realized _tung i. It is a linear

Input the output voltages of a direct current 35 _{more powerful 5 with the first} amplification F ₆ provided, which is about

PD element and an integrating amplifier sums _an integrating amplifier 6 with the integrating time Γ _β

^{sm <} * · is fed back. The integrating amplifier 6 is over

In the following the realization of the individual to _an integrating amplifier 7 with the integral time T ₁

AC regulator types according to the present invention are counter-coupled. The design rules result

can be illustrated in more detail. The integral term 40 _s j _{cn m}

has the frequency response ₁ -

₁ y _ γ τ = -_ Vx T =

^) = T ^ r- ^s ' ^{6 2} ' ^{7 ω} * ^ντ '

. . In Fig. 4, an AC IP circuit is shown

Then T _{1 means} the integer time. On the basis of the 45 The frequency response of a direct current IP-GHede reads: The above-mentioned transposition precedence results for

the frequency response of the corresponding alternating current ("\ __ * ■ Ί" Ρ ^τ

regulator ^ΨΚΡ} pT _t '

fip \ _ ^ P The AC regulator consists of an encryption T ₁ · (p ² + ω ²⁾ "5o _{stronger 8 m} i _{t of the} reinforcing F _8, in whose input _.., _Λ.. '' _r, which χ sum of the controlled variable and the output This is the Origmalfrequenzgang an alternating _{Int an} e _gr ierverstärkers 9 with the integral time T _9-current Integralghedes that of Figure 1 a metal _{acts the ntegr} i i _he verstärker9 is a integrating amplifier 1 with the integration time Ti is used, ^ "3 ^, - _{10 with} the integration time T ₁₀ on the other hand via a further integrating amplifier 2 with the 55 _{k lt} The dimensioning rules are:
Integration time is negative feedback. The frequency response

this amplifier arrangement has the value ν - JL r - JL r - __? __

" Τ ⁸ Ti ' ⁹ ~ 2' ¹⁰ ~ ω ² τ"

^ ⁼ ~ \ _] _ ^ 2 y jY 'Finally, F i shows g. 5, an AC PD circuit.

° The frequency response of a direct current PD element

The comparison of i ⁷ ! " and F (p) provides the loading i _au tef

measurement specification '

¹ ~ 2 * The frequency response of the corresponding alternating

and ^5s current regulator reads:

² ~~ ω ² Ti '

Claims (4)

According to FIG. 5 realized by an amplifier 11 with the gain V11, at the input of which the output voltages of a (direct current) PD element 12 with the time constant T12 and of an integrating amplifier 13 with the time constant T13 are summed. With these designations, its frequency response results in F '(p) = Vn 2T12-p * + 2p + - £ - 2p By comparing the coefficients of F (p) with F' (p) one obtains V11 = V, K12 = - = -, T13 = 10 ω2 r Instead of, as in Fig. 4, by connecting an I element in parallel with a proportional element, the IP element can also be implemented by connecting an I element and a PD element in series. An IPD element is represented by a series connection of a Φ-ΙΡ element and a PD element in the usual way with direct current regulators. All conventional designs can be used as the actuator for the alternating current regulator according to the invention, with rectification possibly being carried out at the regulator output. However, there are also actuators that can be controlled by changing variables. An example of this is the well-known AC-controlled magnetic amplifier, which itself can be produced with either an AC output or a DC output. The fields of application for the contactless AC regulator according to the invention result directly from consideration of the various control problems. For example, it is excellently suited for regulating AC machines, a Ferrari tachometer machine advantageously serving as the actual value transmitter. The only direct current path in the entire control loop is given by the circuit of the excitation winding of the machine. The so-called electric shafts or servo drives for position control work completely without a direct current path, where, thanks to the invention, modulation and demodulation are no longer necessary. Furthermore, AC regulators will be used advantageously wherever the problems of drift, potential separation and impedance matching already mentioned at the beginning are in the foreground. Patent claims: 1. Contactless alternating current controller, which works exclusively with static means from the measuring point to the controller output and whose behavior, defined by the amplitudes of the alternating current quantities, corresponds to the dynamic behavior of a direct current controller, in that the operator ρ in the frequency response of the direct current controller the operator - ^ ~ - is replaced, characterized in that to achieve a Integral behavior an integrating amplifier is provided, which is connected to a further integrating amplifier is fed back. 2. Contactless alternating current regulator according to claim 1, characterized in that it is used to achieve a yield behavior in the negative feedback circuit of a linear amplifier is. 3. Contactless alternating current controller, which works exclusively with static means from the measuring point to the controller output and whose behavior, defined by the amplitudes of the alternating current quantities, corresponds to the dynamic behavior of a direct current controller, in that the operator ρ in the frequency response of the direct current controller the operator - is replaced, characterized in that a time constant amplifier is provided to achieve a time constant behavior, which is fed back via an integrating amplifier. 4. Contactless alternating current controller, which works exclusively with static means from the measuring point to the controller output and whose behavior, defined by the amplitudes of the alternating current quantities, corresponds to the dynamic behavior of a direct current controller, in that the operator ρ in the frequency response of the direct current controller the operator - is replaced, characterized in that a linear amplifier is provided to achieve a PD behavior, at which Input the output voltages of a direct current PD element and an integrating amplifier are summed up. Considered publications:
Hartmann & Braun publication No. 789, "The inductive control", published December 1955; Journal »Control Engineering«, 6th year (Ί958), pp. 2 to 14; Book by J. G. T r u χ a I: "Automatic Feedback Control System Synthesis", 1955, or German translation: »Draft automatic control systems«, published in 1960 by Verlag Oldenbourg, pp. 414 and 428 / 429 1 sheet of drawings 709 707/443 11.67 © Bundesdruckerei Berlin