Contribution à la montée en performance des alimentations DC-DC bipolaires des électroaimants de correction rapide du Synchrotron SOLEIL

Low-power bipolar DC-DC power supplies for fast trajectory correction electromagnets in particle accelerator require low residual current ripple and large bandwidth. The aim is to ensure good stability of the magnetic field provided by these electromagnets, and to offer speed during fast transitions. However, these two objectives are antimonial. ie, the dynamic/residual constraint cannot be met without compromising on residual/dynamic. So, for the fourth generation of the SOLEIL synchrotron, a new full-bridge bipolar DC-DC converter with very low residual and high bandwidth is studied in this thesis. In order to achieve both constraints, the use of the Pulse Width Modulation (PWM) control mode has been studied, considering electromagnetic compatibility (EMC) constraints in compliance with CISPR11 A. In the same perspective, an increase of the switching frequency (Fsw) has been considered. This increase of Fsw pushed us to use the new technology of power components based on Gallium Nitride (GaN) which can operate at high frequencies without deteriorating efficiency. A comparison is always made with the more popular and mature MOSFET Si technology. The points of comparison are implementation, efficiency and EMC. As the EMC of SOLEIL converters is an important issue, an EMC study of the complete conversion chain (DC source - Cable - Converter - Cable - Load) was carried out in both conducted and radiated modes. Indeed, EMC is a crucial point, since power supplies have to cohabit with other highly sensitive equipment.