Design and Test of Slender Salient Pole Hybrid Excitation Generator for While Drilling

The voltage-stabilized generator for Measure While Drilling is used in the oil drilling steering system. This kind of generator's design requirements include voltage regulation range, power generation and the slender design space. Base on the axial/radial magnetic hybrid excitation synchronous generator, we propose a voltage stabilizing generator structure of hybrid excitation with slender salient pole which called SSP-HEG which is composed of hybrid excitation and permanent magnet synchronous generator. The magnetic circuit paths are analyzed by electromagnetic field finite element method. The length of the permanent magnet-salient pole hybrid structure was designed and the regulation range of magnetic flux and voltage was obtained. The main parameters of the permanent magnet excitation and electric excitation generators were designed. The study results show that the salient pole structure of electric excitation can adjust the voltage in two directions which we called Bidirectional regulation generator. The voltage regulation capability of permanent magnet-salient pole hybrid structure in the forward direction is much greater than the reverse direction. The reference voltage U-0 = 344 V. When the rotating speed of the test prototype n = 4000 rpm. The maximum output power of the prototype is P = 3.1 kW. The voltage regulation capability is +/- 8%.