Control device and method for improving the dynamics of a control process

Abstract

The invention relates to a control device (1) comprising a controller (2) for determining a manipulated variable (3) from a reference variable (4) and a measured controlled variable (5), a controlled system (7) containing a controlled variable (6), on which the controller (2) acts via the manipulated variable (3), and a measuring device (8) for providing the measured controlled variable (5) from the controlled variable (6) contained in the controlled system (7). The control device (1) comprises a delay element (9) for the reference variable (4) and a subtracter (10) which, by comparing the time-delayed reference variable (4) with the measured controlled variable (5), provides a control difference (11) which is multiplied by a compensation factor (12) and is added to the measured controlled variable (5) before the latter is supplied to the controller (2). The invention further relates to a method for improving the dynamics of a control process.

Description

[0001] Description

[0002] Control device and procedure for improving the dynamics of a control system

[0003] The invention relates to a control device and a method for improving the dynamics of a control system.

[0004] Cycle time and transmitter speed play a crucial role in the control of dynamic processes. Implementing calculations within a suitable cycle time in the control system is technically straightforward. Transmitters with speeds on the order of approximately 100 ms are commonly available. However, these speeds prove insufficient in highly dynamic processes. Control systems offer limited alternatives for acquiring actual values ​​from an electrical network. If a highly dynamic machine is involved, it can easily begin to oscillate, leading to destabilization of the entire system.

[0005] An exemplary system comprises a combination of diesel generators and battery systems, where the batteries are coupled to the supply networks via inverters and have a control system that operates in the microsecond range.

[0006] This extremely dynamic response speed of the battery systems far exceeds that of the actual value measurements of a conventional control system. When using conventional methods, the control of the inverters is adapted to the performance of the diesel generators and the transmission via the installed transmitters.

[0007] This results in the advantage of highly dynamic converter technology not being utilized. It is known from naval island grids that while calculations are processed in a fast control cycle, the slow actual values ​​were used to slow down the regulation so that extreme overshoots could not occur. The dynamics of the unit being controlled were thus artificially slowed down.

[0008] The object of the invention is to provide an improved control device. A further object of the invention is to provide a corresponding method for improving the dynamics of a control system.

[0009] The invention solves the problem directed towards a control device by providing, in such a control device with a controller for determining a manipulated variable from a reference variable and a measured controlled variable, a controlled system containing a controlled variable on which the controller acts via the manipulated variable, and a measuring device for providing the measured controlled variable from the controlled variable contained in the controlled system, a delay element for the reference variable and a subtractor, wherein the subtractor provides a control difference by comparing the time-delayed reference variable with the measured controlled variable, which is multiplied by a compensation factor and added to the measured controlled variable before the latter is supplied to the controller.

[0010] The control device according to the invention compensates for the lack of dynamics in the measurement. A dead time in the measurement leads to delays in detecting changes in the actual value. A control device that solves the dead time problem can detect the actual value faster and more accurately. This allows the control system to react more quickly to changes and reduce the control deviation. Dead times can also lead to overshoot when the control system reacts to changes in the actual value. An effective solution to the dead time problem helps to minimize this overshoot. Furthermore, it follows that the stability of the control loop can also be improved. The control system can take the necessary compensatory measures to minimize the effects of the dead time and ensure stable behavior.The reference variable typically exhibits no or at least fewer fluctuations than, for example, the manipulated variable and is therefore ideal as a starting value for a correction. Overall, the invention contributes to improved control.

[0011] In an advantageous embodiment of the invention, the compensation factor has at least one constant component. This constant component ensures stability in the control system. If the compensation factor consists only of variable or adaptive components, this can lead to unstable control systems, particularly when unexpected or non-linear effects occur. A constant component acts as a basis or reference point to ensure the stability of the control system. A constant component in the correction factor can be based on prior knowledge or expert knowledge. Corresponding information can also be found, for example, in the datasheet of the transmitter used in the control system. A constant component in the correction factor can also simplify the implementation of the control system. Unlike adaptive or variable correction factors, a constant component does not require ongoing estimation or calculation.

[0012] It is advantageous if the constant value in the control system can be stored. The benefits of preserving information over a specific period and making it accessible for future use are obvious. Storing values ​​allows data to be retrieved and used at a later time. This makes it possible to analyze information, recognize trends, identify patterns, and make decisions based on past data. This can be helpful in troubleshooting. Furthermore, storing values ​​ensures data continuity even if a system or application is restarted or updated.

[0013] Furthermore, it is advantageous if the reference input is externally adjustable. This allows the control system to be flexibly adapted to different requirements and operating conditions. This makes it possible to adjust the system's behavior according to current needs. Moreover, external adjustment of the reference input allows the system to be optimized and its performance improved. By varying the reference input, different operating states can be tested and analyzed to find the best control approach. In many applications, the system may also be subject to disturbances or undesirable influences. By externally adjusting the reference input, these disturbances can be detected and compensated for. The control system can then be adjusted accordingly to minimize the effects of the disturbances and keep the system on course.An adjustable control variable also allows the system to be quickly adapted to changing requirements or objectives. For example, if operating conditions change or new targets are set, the control variable can be adjusted to achieve the desired results. Finally, in some applications, it may be desirable for human operators or users to have the ability to adjust the control variable. This enables direct interaction between the human and the system and allows for intuitive control.

[0014] It is advantageous if the compensation factor is the product of a constant component and a nonlinear component. This regularly leads to better control performance compared to purely linear control systems. The constant component can serve as a baseline and ensure stable control, while the nonlinear component allows for fine-tuning and compensation of nonlinear effects. This can result in more precise, faster, and robust control. It is also advantageous if the nonlinear component is dependent on changes in the manipulated variable over time. This allows the compensation factor to adapt to changing operating conditions or system dynamics. This enables the control system to adjust to changes and ensure continuous and optimal control.The non-linear component can be adjusted in real time to take into account the current system conditions and improve the control accordingly.

[0015] The problem directed towards a method is solved by a method for improving the dynamics of a control system, in which a controller determines a manipulated variable from a reference variable and a measured controlled variable and acts on a controlled system with this manipulated variable, and a controlled variable of the controlled system is measured by means of a measuring device in order to obtain a measured controlled variable, wherein according to the invention the manipulated variable is delayed in time, a control difference between the time-delayed manipulated variable and the measured controlled variable is determined, multiplied by a compensation factor and added to the measured controlled variable before the measured controlled variable is supplied to the controller.

[0016] Advantageously, a constant portion of the compensation factor is determined. It is also useful to store this determined constant portion of the compensation factor.

[0017] Furthermore, it is advantageous if the control variable is supplied from outside the controller and is adjustable.

[0018] Finally, it is advantageous if a non-linear component of the compensation factor is determined as a function of a change in the manipulated variable over time.

[0019] Controlled systems sometimes exhibit better behavior than indicated by the measured actual value, for example, due to a time delay in data acquisition. In such cases, the actual value is closer to the setpoint than the measured value; thus, part of the detected control deviation is already compensated for. By appropriately selecting the compensation factors, the invention allows the control dynamics (compared to the uncompensated system) to be increased without causing oscillations.

[0020] The invention utilizes an algorithm that is integrated into the control loop and reduces the delay of the actual value by means of an "assumption," thereby decreasing the control deviation. The known dynamics of the unit are thus factored into the actual value, allowing the control to be set more aggressively. Should the unit being controlled unexpectedly fail to respond, this can be re-introduced into the control loop using a monitoring algorithm.

[0021] The compensation for the delay makes it possible to apply the control loops even to dynamic control loops, so that this dynamic behavior is not slowed down by the slowest component in the control loop. Previously, the control system was optimized according to this slowest component.

[0022] The invention is explained in more detail by way of example with reference to the drawings. They show schematically and not to scale:

[0023] Figure 1 shows a control device according to the prior art, Figure 2 shows a control device according to the invention and Figure 3 shows another control device according to the invention.

[0024] Figure 1 schematically and exemplarily shows a control device 1 according to the prior art. The control device 1 comprises a controller 2 for determining a manipulated variable 3 from a reference variable 4, which can be supplied and adjusted externally by the operator or another technical system, and a measured controlled variable 5. The reference variable 4 is the quantity to which a controlled variable 6 is to be brought. The control device 1 further comprises a controlled system 7 containing the controlled variable 6, on which the controller 2 acts via the manipulated variable 3, and a measuring device 8 for providing the measured controlled variable 5 from the controlled variable 6 contained in the controlled system 7. The instantaneous value of the reference variable 4 is defined as the 'setpoint', while the instantaneous value of the controlled variable 6 is understood as the 'actual value'.If the reference variable 4 does not change over time, the terms 'setpoint' and 'reference variable' are used synonymously. The control principle is the comparison of the setpoint and actual value of the reference variable 4 with the negatively fed-back measured controlled variable 5. Delays in the measured or determined controlled variable 5, i.e., the measured actual value, arise primarily due to non-ideal measurement data acquisition. Particularly in systems with integrative behavior ("memory"), there is a high risk of oscillations. To prevent such oscillations, the control system must be heavily damped, i.e., its dynamics must be reduced.

[0025] Measuring device 8 causes a delay in signal processing. This can lead to instability in the control system. Particularly in fast control loops, the delay can lead to undesirable oscillations or even system failure. The signal processing delay can reduce control accuracy. The control system may not react quickly enough to changes in the controlled variable or may not be able to track them accurately enough. When signals are processed with a delay, the system may be more sensitive to disturbances or noise. The delay can cause the system to react too slowly to disturbances or to amplify disturbance signals. The signal processing delay can impair the overall performance of the control system. The system may not be able to achieve the desired performance or efficiency.The invention provides a suitable control device 1 or a corresponding method for improving the dynamics of a control system in order to minimize these potential consequences. Figure 2 shows an embodiment of a control device 1 according to the invention. Compared to the prior art example in Figure 1, the inventive control device 1 further comprises a delay element 9 for the reference variable 4, a subtractor 10 which provides a control difference 11 by comparing the time-delayed reference variable 4 with the measured controlled variable 5. This control difference 11 is multiplied by a compensation factor 12 and added to the measured controlled variable 5 before the measured controlled variable 5 is fed to the controller 2. The compensation factor 12 has a constant component 13 and is typically storable in the control device 1.

[0026] Figure 3 shows a further embodiment of an inventive control device 1. In contrast to the embodiment of Figure 2, the compensation factor 12 results from a product of the constant component 13 and a non-linear component 14, wherein the non-linear component 14 has a dependence on a change 15 of the reference variable 4 over time.

Claims

Patent claims 1. Control device (1) with a controller (2) for determining a manipulated variable (3) from a reference variable (4) and a measured controlled variable (5), a controlled system (7) containing a controlled variable (6) on which the controller (2) acts via the manipulated variable (3), and a measuring device (8) for providing the measured controlled variable (5) from the controlled variable (6) contained in the controlled system (7), characterized by a delay element (9) for the reference variable (4) and a subtractor (10) which provides a control error (11) by comparing the time-delayed reference variable (4) with the measured controlled variable (5), which is multiplied by a compensation factor (12) and added to the measured controlled variable (5) before the latter is supplied to the controller (2).

2. Control device (1) according to claim 1, wherein the compensation factor (12) has at least a constant component (13).

3. Control device (1) according to claim 2, wherein the constant component (13) is storable in the control device (1).

4. Control device (1) according to one of claims 2 or 3, wherein the guide variable (4) is externally supplied and adjustable.

5. Control device (1) according to claim 2, wherein the compensation factor (12) results from a product of the constant component (13) and a non-linear component (14).

6. Control device (1) according to claim 3, wherein the nonlinear component (14) has a dependence on a change (15) of the manipulated variable (3) over time.

7. Method for improving the dynamics of a control system, in which a controller (2) consists of a reference variable (4) and a- a manipulated variable (3) is determined from the measured controlled variable (5) and this manipulated variable (3) acts on a controlled system (7), and a controlled variable (6) of the controlled system (7) is measured by means of a measuring device (8) in order to obtain a measured controlled variable (5), characterized in that the reference variable (4) is time-delayed, a control error (11) between the time-delayed reference variable (4) and the measured controlled variable (5) is determined, multiplied by a compensation factor (12) and added to the measured controlled variable (5) before the latter is supplied to the controller (2).

8. Method according to claim 7, wherein a constant fraction (13) of the compensation factor (12) is determined.

9. Method according to claim 8, wherein the determined constant fraction (13) of the compensation factor (12) is stored.

10. Method according to one of claims 7 to 9, wherein the reference variable (4) is supplied from outside the controller (2) and is adjustable.

11. Method according to one of claims 7 to 10, wherein a non-linear component (14) of the compensation factor (12) is determined as a function of a change (15) of the manipulated variable (3) over time.

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