This paper presents a mathematical modelling for design the control system of a liquid. The system are consists of one and two tanks of a liquid. To confirm the achieved mathematical modelling is used to design P PI PD and PID controller in the frequency domain. The experimental results are indicated as the following. An one tank of a liquid controlling The controller can be control the liquid level to set point with in 100s. In the case of a disturbance occurs in the system it is perform by drain a liquid. As same as the controller it can be control the liquid level into the steady state. In the part of the liquid control this is the interaction between two tanks. The experimental results of the system operation the controller can be control the liquid into the set point both occur disturbance and without disturbance respectively

This paper presents a design of the control system to control AC/DC converter. Algorithm of a control system design consists of the output voltage loop control used a fuzzy gain scheduling of PI control and the current loop control used a hysteresis control which is described in this paper. The evaluation of the proposed control system is used to control an isolated CUK AC/DC converter operation with a 250W load and a -48V output voltage. The system is achieved as the following; the tight output voltage both the steady state operation and the transient response a power factor is nearly unity and the waveform of input current is nearly sinusoidal. In addition the control system design is simple and uncomplicated