What is Proportional Integral Controller?
PI controller or Proportional controller is a combination of Proportional controller action and Integral controller action which is designed to regulate a process variable based on its setpoint and manipulated variable. Also, it can be identified as a combination of proportional and integral controllers.
What are Proportional and Integral Controllers?
Proportional Controller: Proportional Controller in electronics engineering continuously adjusts the output based on the current error signal. The p term or proportional term calculate the current error from the setpoint and the current manipulated variable output. It generates a control signal to regulate the error.
Co(t) ∝ e(t)
Co(t) = Kp . e(t) ———–(i)
Where,
Co(t) = controller output at time T,
e(t) = error at time t(SP-PV),
Kp = tuning constrains for proportional action.
Integral Controller : In Integral Controller, the I term or Integral term actuates the past error over time and generates a control action to eliminate the accumulated steady-state error. It ensures that even small errors are eventually corrected. It eliminates offset but can lead to sluggish responses and overshooting if too aggressive.
This is represented as :
It can be represented mathematically as :
Co(t) ∝ ∫ e(t) dt
Co(t) = Ki . ∫ e(t) dt ———–(ii)
Where,
ki = tuning constrains for integral action,
others are same as equation number (i).
Proportional Integral Controller – Control System
The proportional controller commonly known as PI controller is an essential part of the Industrial Automation and Control system. It is a closed-loop feedback control mechanism that aims to adjust the process variable by manipulating the variable based on the error between the setpoint and the process variable. It strikes a balance between quick response to deviations and long-term error elimination. Tuning the controller allows adjustment to meet the desired value.
Table of Content
- Definition
- Equation and Diagram
- Block Diagram
- Effects
- Tuning
- Applications
- Advantages and Disadvantages
- Comparison with Other Types of Controllers