Enhancing the current stability of the TPS booster ring dipole magnet power supply in DC mode

The Taiwan Photon Source is a third-generation 3 GeV synchrotron light source. Since the successful operation of its first beamline in 2013, efforts have been made to improve the low-current output stability of the dipole magnet power supply in the booster ring under DC operation mode. This paper proposes a solution to enhance the thermal management of the power supply control board by enclosing the current control and compensation circuits within a temperature-controlled housing. This approach reduces the impact of environmental temperature fluctuations on the magnet power supply. In addition, isolated power ICs and DC cooling fans are further introduced to stabilize the internal temperature of the main control board. A new PCB layout was developed using SMT packaging, allowing key components to be integrated into a copper temperature-controlled enclosure and ensuring the current compensation circuit operates under consistent thermal conditions. As a result, the DC stability of the TPS booster dipole power supply has been significantly improved. Experimental results show that at the 100 MeV injection point, where the operating current is 30 A, the current drift was reduced from 35 mA to less than 10 mA. This enhancement markedly improves the performance of the booster dipole power supply in DC mode and lays a foundation for improved reproducibility at the injection point under future AC operation.