Pid Controller Literature Review

Chapter 2

Literature Review

Theory and law

PID Controller

PID controller is one of the methods for temperature control and is widely used in process control industry due to simple design and easy to implement in industrial [1]. PID controller consists of three controllers, which is proportional (P) controller, Integral (I) controller, and derivative (D) controller [2]. The equation for output of the PID control can be described as: u(t)=K(e(t)+ 1/T_i ∫_0^t▒〖e(τ) dτ+ T_(d ) de(t)/dt〗) [2]

Which e is the control error, K is the proportional (P) gain, Ti is the integral (I) time, and Td is the derivative time. Figure 1 shows the PID controller design using operational amplifier (op-amp). Figure 1: PID controller design [3] Proportional controller functions as to

Peltier effect was discovered in 1834 in a contact of two metals [13]. The thermoelectric cooling has several benefits, which is free from maintenance, free from moving parts, and free from vibration and acoustic noise. Thermoelectric cooling effect may be replaces the cooling method based on CFC that may cause the thinness of ozone layer [13].

Peltier effect has been defined as absorption of heat absorption of the junction of two conductors or its cooling through which a DC electric current flows. The absorption of this heat or its evolution depends on the direction of the electric current, and per unit time, it is equal to

Q_II=(〖II〗_1-〖II〗_2)J

where 〖II〗_1-〖II〗_2 are the Peltier coefficients of the conducting materials at each side of the junction and J is the total electric current. Figure 4 shows the schematic of the thermoelectric couple [13]. Peltier heat is reversible, and will remain constant but in opposite direction when the direction of current is reversed [14]. Figure 4: Schematic of the thermoelectric