Operation of a Fuzzy Controlled Half-Bridge DC-Converter as a Welding Current-Source

Abstract

AbstrakSebuah sumber arus mesin las terkendali logika Fuzi (FCWM) IntroductionThe arc welding process consists of heating the metal surfaces of the parts to be joined to their plastic Temperature through passage of high AC or DC electric current. The electric arc (that is discharge into a gas) is ignition between the electrode and the pieces at low voltage drops (10-40 V) at high currents (5-2000 A) [1].The manual-metal arc welding with consumable electrodes (sticks) form approximately 30% of all welding systems [1]. The manual welding machines use the high frequency inverters to provide high capacity currents during operation. The inverter operation frequency is between 20-100 kHz through the use of semiconductors devices with power performances (MOSFET and IGBT transistors) [1]. In this paper a Half Bridge high frequency inverter is used to provide an appropriate current on welding point.The conventional analog welding machine generates the steady PWM for driving IGBT of its inverter and controls the output welding current by turning on or off of IGBT switches [4]. So it can not regulate well the quality of welding current to track the setting welding Current [2], [3]. In The other control method, the output welding current controlled by changing the duty cycle of PWM. The changes Based on the error between the values of feedback output welding current and the setting current applied to a fuzzy controller. The requirements for a good DC-arc welding machine can be explained as the following: Firstly, an output welding current easily achieves the setting welding current at first welding. Secondly, the output welding current of an electric arc must be maintained constant during the welding process [2]. In this paper we use a fuzzy controller to change the duty cycle of PWM system. The Fuzzy controller will adjust the e → 0 as t → ∞. Also by using a Hot-Start function the output current of Fuzzy controlled welding machine (FCWM) easily achieves the setting current at welding start of state. So the electric arc