Temperature Control System Feedforward Control to Prevent Oscillation
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Solution Overview
Problem
Conventional temperature control systems, such as cooling or heating circuits, often experience oscillations and overshooting due to the inertia of the system and simultaneous manipulation by the compressor and expansion valve, leading to instability and longer time to reach the setpoint.
Innovation Solution
Implementing a pilot control method that pre-regulates the manipulated variable and determines the expected time course of the thermal variable, allowing controller intervention only when the deviation exceeds a threshold, thereby preventing oscillations and ensuring stable and quick setpoint attainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feedback control is used with compressor and expansion valve acting simultaneously, then the system can respond to temperature deviations, but controller oscillation occurs due to system inertia and identical manipulated variables
Solution Approach 1:
The patent applies feedforward control by calculating the expected thermal variable profile based on manipulated variable changes before they are actually applied. This preliminary action allows the controller to anticipate system response and avoid oscillations, directly resolving the contradiction between control stability and response time.
2Loss of time
If aggressive controller intervention is applied to quickly reach setpoint, then response time is reduced, but overshoot of the controlled variable occurs due to system inertia
Solution Approach 1:
By determining the expected temporal profile of the thermal variable in advance, the controller can pre-adjust the manipulated variable to account for system inertia. This prevents overshoot while maintaining fast response, resolving the contradiction between response speed and control precision.
Solution Approach 2:
The controller compares the actual thermal variable with the expected profile and adjusts intervention based on the deviation. This feedback mechanism allows aggressive action when needed while preventing overshoot, resolving the contradiction between response time and precision.
3Manufacturing precision
If continuous controller intervention is applied to maintain setpoint, then temperature precision is improved, but controller oscillation occurs due to system inertia
Solution Approach 1:
The controller continuously monitors the deviation between actual and expected thermal variable profiles and adjusts intervention accordingly. This intelligent feedback prevents oscillation while maintaining precision, resolving the contradiction between temperature precision and control stability.
Data Source
Figure 1~2
AI summary
The invention relates to a method (200) for operating a temperature control system (100) comprising at least one compressor (110) and at least one expansion valve (130, 132) as well as at least one component (140, 142) to be temperature controlled, comprising controlling a thermal quantity of the temperature control system (100) to a setpoint using a compression power and/or a valve position of the at least one compressor (110) or the at least one expansion valve (130, 132) as a manipulated variable, comprising pre-controlling (212, 222) the manipulated variable, determining (214) a time-dependent profile of the thermal quantity expected in response to the pre-controlling (212), and controlling (216, 226) the thermal quantity taking into account the determined expected profile. Furthermore, a computing unit (160) and a computer program for carrying out such a method (200) are proposed.