Optimising the start-up of a 10Hz booster power supply

The Synchrotron Radiation Source (SRS) at Daresbury Laboratory has a 600MeV Booster, fed by an energy storage power supply configuration (White Circuit). The design consists of two power supplies : an AC source to supply the losses to the parallel resonant circuits and a DC supply to fully bias the AC sinewave. In a recent modernisation of the control electronics, different methods of achieving reliable synchronisation of the AC source on switch-on have been investigated. The circuitry must deal with the high Q value of the resonant circuits and variation in resonant frequency with both ambient temperature and the applied DC current. This paper presents the different designs explored to improve the efficiency of start-up and discusses the problems encountered. The chosen design and test results are detailed with recommendations for future investigations.