An opto-isolator based linearization technique of a typical thyristor driven pump

► The proposed optocoupler successfully measure the motor load current and flow rate. ► The nonlinear characteristic of the pump has been successfully linearized. ► Only two op-Amps have been used to design PIDD−1 controller. ►PIDD−1 action reduces the noise due to incidental change of motor speed, supply voltage, etc. ► Percentage deviation within tolerable limits and a very good linearity is observed.