DD272749A1 - METHOD FOR CONTROLLING INTERFERENCE IN THREE-PHASE CIRCUITS WITH VECTORIAL CURRENT CONTROL - Google Patents

Abstract

The invention is used in particular for the compensation of interfering forces, which are caused by alternating components in the intermediate circuit voltage of pulse converters. According to the invention, the current control is extended by additional controllers for both current components, which operate in a coordinate system with a fixed frequency (the dominant interference erosion frequency) by subjecting the system deviations present in the synchronous coordinate system of the fundamental frequency to a further coordinate transformation. The measure considerably improves the dynamics of the regulation. figure

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a process for the A usregelung of at Siöreinflüssen of inverters fed three-phase systems, the werdon caused by the AC components in the input voltage of the inverter. It is applicable, for example, in frequency-controlled three-phase motors operated via a pulse converter, in particular when using line-side converters with a low number of pulses or a low network-side phase number (mains converter on the single-phase network).

Characteristic of the known state of the art

From DE-OS 3116342 (H02 P13 / 18) a method is known in which the voltage generated by sinusoidal pulse width modulation can be corrected by measuring the intermediate circuit voltage and subsequent multiplication with the triangular auxiliary voltage required for pulse width modulation o'er output voltage. Similar methods are the subject of DE-OS 3211183 (H02 P13 / 18) and DD-PS 255011 (G 05 B13 / 02). The method has advantages in such voltage-controlled machines, but has dynamic disadvantages in the case of other drive methods, especially if superimposed current-regulating loops are present, since phase shifts result due to the different signal propagation times in the control loops. However, the current control alone is not able to compensate for the disturbances, because the controller can not be set simultaneously to optimal Störgrößenverhalten and optimal command variable behavior.

From DE-OS 2932091 (H02 M Vm) an arrangement for the suppression of Störsignalcn in control devices for the input-side converter (mains converter) is known, in which an additional control channel consisting of a selective filter and a PD element, starting from the interfering signal-affected actual value the mains current, is provided, whose

Output variable is connected to the controller output of the mains control circuit. This ensures that the interference frequency can be selectively cedämpft without the dynamics of the Hauptrogolkreises for the Netistrom is adversely affected. However, this solution is only suitable for Weachseigrößeregclungen.

Object of the invention

Object of the invention is ns the influence of Wechselanteilon in the DC link voltage on the harmonic content of the motor currents to verr ngern and thus to avoid the emergence of additional Per.delmomente.

Explanation of the West ns of the invention

The invention has for its object to provide a method for Avisregelung of harmonics' n the motor currents, which are caused by alternating components of known frequency in the DC link voltage.

According to the invention, the object is achieved in that a current vector control operating in the synchronous coordinate system (KOS) of the common frequency f is supplied on the input side to the current vector nominal values and actual values in the synchronous coordinate system and which generate control voltage components of the voltage vector u u in the same coordinate system on the output side. which are then transferred via a nachgeordneta back transformation into the stationary coordinate system, is extended by additional controller for both current components. These work in the fixed-frequency coordinate system f _x = f, + f "by transforming the control deviations present in the synchronous coordinate system of the fundamental frequency with the angle θ, = 2n · f, t into the coordinate system rotating with the interference frequency ω, + ω , so that there are equal quantities with respect to the Störf.-equenz. The Zusatzregier preferably have the same structure with I-shares. Their output quantities y "y _y are transformed back into the synchronous coordinate system of the fundamental frequency f 1 via the transformation angle _z and applied to the controller output variables of the current component controllers in the synchronous coordinate system.

It is advantageous to tune the additional controller and the additional coordinate transformation to the highest dominant or essential Siörgrößenfrequenz.

If there are several significant interference frequencies, then a parallel extension can be realized by additional additional controllers with appropriate coordinate transformation.

Furthermore, 3s is cheap; the coordinate transformation subsequent to the additional controllers in the synchronous coordinate system of the fundamental frequency f, with the additional angle θ = θ, + f (ωβ T) compared to the input side transformation θ = -θ, to compensate for runtime effects of the control.

In addition, it is expedient to nachi-chalten the additional controllers a decoupling network in order to avoid mutual coupling of the additional control loops depending on the Sukfrequenzen ausuregelnden.

embodiment

The invention will be explained in more detail with reference to the following embodiment of the control of a three-phase motor. The drawing shows the in synchronous KOS the fundamental frequency f ₍ working current component control circuits, consisting of the two controllers 1 the decoupling network 2, the vector rotator 3 for coordinate transformation of the synchronous to the stator KOS, the inverter 5 for feeding the AC motor 6, the coordinate converter 7 Formation of the stator-fixed current component actual values , _αιι χ, i, pi, ₍ from the actual phase current values and the vector master 4 for coordinate transformation of the current distance from the stator to the synchronous KOS, i _sc j ist.

They are supplemented by additional control loops, the present synchronous KOS control deviations e _d, e are supplied to _q a Vector Design ^r dreher 8, of the KOS the dominating a transformation of the control deviations or to be suppressed harmonic f "= f _s + f, by of the transformation angle ¹ θ ₂ = 2n · f, · t, so that the control deviations e _x , e _y arise, are passed to the two regulators 9 for the χ and y components, which are then due to the contained in their! Proportions generate the manipulated variables y "y _y for the compensation of the interference components. Thereafter, these two manipulated variables are supplied to the vector rotator 10, which by means of the transformation angle θ, performs a back transformation into the synchronous KOS, so that the control voltage signals U _1x , u "arise. For dfe transformation in vector twister 8 applies

e "= coso, ed + sindiOg (1)

e _y = -sinOjed + coso, e ₀ (2)

The inverse transformation in the vector 10 is:

_x -sinö ₂ y _y (3)

u, _y = si η θ, y, + cos Q ₁ y _y (4)

The coupling of the control voltage signals u ", u, _{y of} the additional control loops in the synchronous control circuits is finally

j over the mixing points 11, the modified control signals u _{S (} j *, u _sq .

This makes it possible for d (in the case of an inverter supply via the actuator to be influenced by a low-frequency DC voltage u _d

(5)

UII

or with complex representation

_{U (I} ü (1 ₊ ^ (e _{+ θ} (6)

Ud 2

on the stator voltage vector acting in the stator-fixed coordinate system

_Uz. _(e J (9. + ^ _z - _Wl tv _z ) _{+ e} J (9. + Vz + _{) (7)}

2 ö _d

and the stator currents having the frequencies ω ,, ω. - ω, and ω, + ω, are liable to suppress. The advantages of the invention over previously known solutions are

- That a rapid compensation of certain dominant harmonics in the stator current is possible without significant speed errors;

- That both the follower (+ ω ₂ ) and the counter-rotating | -ω ₂ ) Störgrößenensystem is ausregelbar, as it falls into the transmission band of the additional controller;

- That all disturbances that occur at a frequency ω, <ω <ω _2, can also be quickly corrected kö'.nen, since these disturbances in the coordinate system ω _χ = ω, + ω, act as sub-oscillations;

- That the additional controller may have an identical structure to the main controllers, and thus the otherwise larger Vi Ifalt is reduced by control principles, thereby reducing development, commissioning and testing costs;

- That additional smoothing means can be saved in the intermediate circuit and higher-pulse input power converters are not mandatory.

Claims (5)

1. Method for the control of disturbances in three-phase current systems with vectorial current control, ζ. B. field-oriented bb .. iebener three-phase motors, starting from a nominal Islwert comparison of components of the current vector in the synchronous coordinate system of the fundamental frequency f _s, the control and possibly decoupling of both components is made so that the control voltage components of the control voltage vector in arise the same coordinate system, which then transferred via an output side arranged inverse transformation into the stationary coordinate system and are used to form the voltage vector via the drive, characterized characterized -, the work in a coordinate system with a fixed frequency f _x = f _s + f _z, by the present in the synchronous coordinate system of the fundamental oscillation frequency control deviations (e _d in that the current vector control in the synchronous coordinate system of the Grundschwingungsfrequenzfs expand to additional regulator (9) for both current components e _q ) a further coordinate transformation with the transformation angle θ _ζ = 2π · f _z · t be subjected; - That the additional regulator (9) for both current components I shares and preferably have the same structure; - That the output variables of the additional controller (9) y _x and y _{y are} transformed by means of Transformationswinkgl - θ _ζ back into the synchronous coordinate system of the fundamental oscillation frequency f _s and switched to the controller output variables (u _sd , u _sq ) of the current vector control in the synchronous coordinate system, before these in stationary coordinate system. 2. Moving according to claim 1, characterized in that the additional controller (9) are designed for the highest dominant Störgrößenfrequenz in the system. 3. The method according to claim 1, characterized in that a plurality of parallel operating additional controller (9) are designed for multiple dominant Störgrößenfrequenzen. 4. The method according to claim 1 to 3, characterized in that the additional regulators (9) downstream inverse transformation into the synchronous coordinate system of the fundamental frequency f _s with an additional angle θ - & _z + f (ω _θ · t) relative to the input-side coordinate transformation with θ = -θ _ζ for the additional regulation. 5. The method according to claim 1 to 4, characterized in that the auxiliary regulators is assigned a decoupling network for both current components.