DE4026091A1 - Regulation system for electrical machine drive - uses predicted variation for calculation of required optimal compensation - Google Patents

Abstract

The regulation system incorporates prediction and compensation of a periodic variation, with a new prediction determined over each period for the following period. Pref. the period is dependent on the angular velocity or rotation angle of the electrical machine drive. The determination of the optimal correction function for the periodic variation at a constant time point before the occurrence of the real variation is sufficient for the response time of the setting components used for compensating the variation. USE - For compensating periodic torque loading variation.

Description

The invention relates to a control system for drives whose Load moment contains an angular period component.

It is known to be driven, in particular electrically Machines using the angular speed of the machine of a speed control loop.

The main disturbance in such a control system is load the moment of the machine (1).

However, it has proven to be a disadvantage that especially in a load torque fluctuating over the angle of rotation of the machine, the machine runs out of round.

This is due to the fact that a regulation in principle can only react when a disturbance is a deviation has brought about from the ideal state (2).

With a prediction of the load moment it would be possible to Counteract the effect of the load torque before this occurs at all.

The invention has for its object to a control system create that the angle-dependent load torque during operation predicted and thus an optimal feedforward control realized.

Previous solutions have included measuring the disturbance variable Test signals ahead, which was carried out before operating the system must be (3).

The basic idea of this invention is now that Load torque for rotating machines contains a proportion that periodically to the slowest rotating part of the machine. Due to the fact that the main disturbance variable load torque at every revolution newly determined, have slow changes in the system, e.g. B. on Due to temperature dependencies, no more influence.

That is, with the knowledge of the load moment of a previous one You can turn a non-causal disturbance variable make such that z. B. also dead times in the Stell structure of the drive system can be compensated.

In the embodiment of the invention it is proposed that  determine the angle of rotation of the machine related load torque then digitize and in an electrical Store memory.

This load moment can then be reached before it is reached again Angle of rotation be switched so that there is no noticeable Influence of the real load moment comes.

Further embodiments of the invention are in the subclaims and the description below.

The invention is described below using an exemplary embodiment explained in more detail.

Fig. 1 block diagram of the system.

Fig. 1 shows the block diagram of the control system. The control system shown here as a signal flow diagram was implemented as a program in a microcomputer. The coordinate transformers ( 14, 15, 19 and 20 ) and the arithmetic unit ( 18 ) in particular could thus be implemented very easily.

The input signal of the exemplary embodiment is the angle of rotation speed setpoint of the drive.

The difference between the angular velocity setpoint and the actual angular velocity is fed to an angular velocity controller ( 1 ).

The output of the angular velocity controller ( 1 ) is given to the power section of the drive via a maximum torque limiter ( 2 ), modeled by a dead time element ( 3 ) and a 1st order delay element ( 4 ). The output torque of the drive is present at the output of the 1st order delay element ( 4 ). This torque is now fed into the system ( 21 ) to be driven. The system ( 21 ) to be driven is modeled internally by two integrators, ( 5 ) and ( 6 ), which are negative-coupled via a non-linear element ( 7 ) with an upstream multiplier ( 8 ). From the output torque of the drive, the load torque is now subtracted from ( 7 ), thus forming the acceleration torque. The ramp integrator ( 5 ) generates the angular velocity of the drive from this acceleration torque. With this angular velocity, the track integrator ( 6 ) now forms the angle of rotation of the drive. This angle of rotation is now multiplied in the multiplier ( 8 ) by the factor n, which characterizes the reduction ratio to the slowest rotating shaft and thus the period of the load torque.

The real load torque, which corresponds to the output signal of the non-linear element ( 7 ), is determined by means of a Luenberger observer ( 4 ), made up of a model ramp integrator ( 10 ) and a feedback amplifier ( 9 ).

At the output of the feedback amplifier ( 9 ) the observed load torque can now be taken off.

The multiplier ( 11 ) generates from the measured angle of rotation of the drive by multiplication by the factor n the system angle of rotation to which the load torque is periodic. The observed time-dependent load torque is now transformed into a system torque-related load torque in the coordinate transformer ( 14 ).

These coordinate transformers simultaneously symbolize a memory in which the transformed variable is stored. The multipliers ( 12 ) and ( 13 ) each generate the corresponding lead angle or dead time angle from the constant calculation lead time Tv or the total dead time Tt of the actuating and calculation elements.

The arithmetic lead angle is then subtracted from the angle of rotation that characterizes an entire period of the load torque. In the coordinate transformer ( 15 ), the load torque transformed in the coordinate transformer ( 14 ) is transformed back with the calculated angle. At the output of the coordinate transformer ( 15 ), the predicted load torque is exactly earlier than the real load torque by the calculation lead time Tv.

In the lead element with a proportional component ( 16 ), this predicted load torque is converted in such a way that the influence of the first-order delay element ( 4 ) is just compensated for.

This interference correction function determined in this way is now fed to the model maximum torque limiter ( 17 ). The difference between the output variable and the input variable corresponds to that interference correction function whose value range lies outside the value range that can still be processed linearly by the system. This difference signal can no longer be processed linearly and thus corresponds to the large signal behavior.

The arithmetic unit ( 18 ) adds this difference signal to the output signal of the model torque limiter in connection with the coordinate transformer ( 19 ) so that the resulting disturbance variable correction function does not exceed the maximum value range of the model torque limiter ( 17 ).

This takes place in such a way that part of the difference signal is added up at this point in time before the maximum torque limiter cuts the output signal of the first-order retaining element with a proportional component ( 16 ). To achieve this, the coordinate transformer ( 19 ) is required, which provides the output signal at the right time.

This interference correction function generated in this way is then added by means of the coordinate transformer ( 20 ) during the correct rotation angle to the output signal of the angular velocity controller ( 1 ). The correct angle of rotation is determined by adding the system angle of rotation with the angle of rotation, which corresponds to an entire load torque period, and the dead time angle of the multiplier ( 13 ).

bibliography

(1) Kümmel, F .: Electrical Drive Technology, BerlinDe Heidelberg · New York 1971, pp. 378-388
(2) Unbehauen, H .: Regelstechnik 1, Braunschweig / Wiesbaden 1989, 6th revised edition, pp. 6-12
(3) Kuntze, H.-B., Jacubasch, A., Salaba, M., Hirsch, U., Mitschke, H., Munser, R., Richalet, J .: Experience in the implementation of a novel predictive control concept for Industrial robots, automation technology at., 36th year, issue 6/1988, pp. 208-214
(4) Luenberger, DG: Observers for Multivariable Systems, IEEE Transactions on Automatic Control AC-11 (1966), pp. 190-197.

Claims (9)

1. Apparatus and method for regulating systems whose disturbance variables contain a time or rotation angle period component, characterized in that this time or rotation angle period component is predicted and compensated. 2. Device and method according to claim 1, characterized, that the time or rotation angle periodic disturbances during each period for the subsequent period be newly predicted. 3. Device and method according to claim 1, characterized, that the time or rotation angle period from the angle speed or the angle of rotation of the drive is derived. 4. The device and method according to claim 1, characterized, that the compensation by a non-causal disturbance connection is realized. 5. The device and method according to claim 2, characterized, that the time or angle of rotation periodic disturbances be determined by means of a Luenberger observer. 6. The device and method according to claim 4, characterized, that the optimal interference correction function is always one constant time before the real disturbance variable occurs is determined.   7. The device and method according to claim 4, characterized, that when determining the optimal interference correction function distinguish between large and small signal behavior becomes. 8. The device and method according to claim 4, characterized, that dead times of the actuators in the calculation of the optimal interference correction function can be included. 9. The device and method according to claim 6, characterized, that for determining the optimal interference correction function the interpolated angular velocity change based on the real time of the interference becomes.