Microcontroller based design of rectifier for chemical surface treatment

The purpose of this paper is to design a controlled IGBT rectifier which produces a pure DC current used in chemical surface treatment of metal. During the chemical treatment process, the load resistance is changing continuously. To maintain the current fixed at an appropriate value, a feedback signal from the load is read into the control circuit. The outputs of the developed rectifier are 10VDC and current in the range from 0-250 A. The designed rectifier is composed of IGBT´s H-bridge, high frequency center tap transformer, a liquid crystal display to view two values which are the required and the actual currents, a keypad to input the required current, and PIC16F877A microcontroller. The microcontroller´s pulse width modulation (PWM) technology is used to generate a DC current that driving the H-bridge with 150KHZ. Finally, the rectifier circuit is simulated and tested using PROTEUS and PSIM packages before being implemented.