Balun Technology for Bipolar Pulsed Power Supply

Abstract：

A new type slotted pipe kicker with advantage of low coupling impedance is adopted for the major upgrading of the Beijing Electron Positron Collider (BEPCⅡ). A bipolar pulsed power supply is needed for the new type kicker. In order to avoid difficulties caused by the floating-thyratron scheme, a balun is introduced into the LC series resonance circuit with a grounded thyratron. The current balance degree between primary and secondary coils must be considered for the balun as a high-voltage fast-pulsed transformer for the special purpose. The unbalanced currents include magnetizing current and equivalent current of eddy-current loss in core. A nanocrystalline tape-wound toroid annealed in transverse magnetic field is chosen for the balun. To reduce leakage inductance, a simply parallel flat structure is adopted in design of transformer primary and secondary conductors. The test results on the prototype confirm the design theory and current balance degree of the balun reaches the design target of D<1%.