An Improved Scheme for Extended Power Loss Ride-through in a Voltage Source Inverter fed Vector Controlled Induction Motor Drive using a Loss Minimisation Technique

Abstract

The ability of an electrical drive to continue operation without tripping in spite of short-duration voltage sags or power supply interruptions is known as power failure ride-through capability. Critical production processes in industries require the drives to smoothly ride-through during momentary power interruptions. The reliability of the drive is dependent on the maximum duration for which a total power supply failure can be tolerated without process interruption. This paper presents a method to extend the duration of the ride-through in voltage-source-inverter-fed vector-controlled induction motor drives with a front-end diode bridge rectifier. The proposed method minimizes the losses in the system during the ride-through, thereby enabling a longer ride-through duration. The method only requires a modification of the control software and hence is easy to implement. This paper also briefly describes two conventional methods used for ride-through and compares the proposed method with the conventional methods to clearly bring out its advantage. Simulation study using MATLAB/PLECS verifies the effectiveness of the proposed method. Hardware implementation of the method on a 30-kW induction machine indicates an extension of up to 34% in the ride-through duration with the proposed method, as compared with the conventional method.