ANALYSIS OF CONTROL TECHNIQUES OF WELDER POWER SUPPLY

Abstract

Welding is an unavoidable practical unit for every manufacturing industry. In industries like aerospace and nuclear where weld of high accuracy is a must, electron beam welding (EBW) are used. For effective operation of EBW a stable ripple free high voltage DC power supply is essential. More over the filter elements of the power supply should be very less to reduce the stored energy. This dissertation concerns with the analysis of high frequency linked power conversion schemes for power supplies used in specialized application like EBW. The report provides analysis of the chopper inverter based topology and its performance with different controllers. Based on design the simulation model of the converter along with different controller is developed. A type-3 compensator is designed based on Bode plot and implemented to the Power supply unit (PSU) for simulation. PI voltage controller whose parameters has been synthesized using Ziggoler's and Nichol's frequency response method and implemented to the power supply unit. A PI controller whose parameters can be changed dynamically as per the output information is designed and implemented. Fuzzy controller is employed whose membership function and rule sets are simultaneously designed based on expert Knowledge. An Artificial Neural network (ANN) based controller is synthesized and implemented. The Sliding mode controller is employed to the power supply whose gains are synthesized from the mathematical model of PSU. The simulation result for above said controllers has been reported.