THE IMPROVEMENT OF EDM PULSE GENERATOR PERFORMANCES BY USE OF THE NEWS SILICON-CARBIDE MOS TRANSISTORS

Abstract

In the first part of this article the authors make a short presentation of the resistive current limitations technique used in Controlled Pulses Generators for die Sinker Electrical Discharge Machining. In the second part, the inductive current limitations technique and schematic principia of EDM Pulses Generator based on Buck Converter are also presented. The results of circumstantial simulation for basic Buck Converters using different electronic power devices, presented in the third part, gives in evidence the superiority of SiC MOS Buck Converters in terms of electrical efficiency. An electrical schema for the gap emulation is conceived for use in simulation. The behaviour of SiC MOS Full Bridge EDM Pulses Generator is simulated using electrical schema presented in the fifth part, where the peak current limiting technique was used. The possibility to achieve bipolar ignition voltage, for reducing the ignition time, was indicated in presented example. A good electrical efficiency for switching frequency at high values permits to obtain EDM pulses of short duration. In the final part an electrical schema was conceived for simulation, using interleaved technique for achieve high value of positive current discharge for roughing machining. A desired profile of discharge current pulse can be easy obtained and this permits to minimise the electrode tool wear.