A new micro fluxgate magnetic sensor using micromachined 3-dimensional solenoid coils has been designed, fabricated, and characterized in this work. The fluxgate sensor adopts a ring-type shape and second-harmonic principle, and is composed of exciting coils, a ring core, and sensing coils. Using a newly developed UV lithography-based thick photoresist process and electroplating techniques, planar three-dimensional magnetic fluxgate sensors were fabricated on a silicon wafer. The measured sensor output shows excellent linear characteristics over the range of ±500 µT with a resolution of approximately 60 nT, achieving the sensitivity of 8360 VT 1 • Furthermore, this sensor also shows a wide sensing range of ± 1.5 mT. Using this highly sensitive, on-chip fluxgate sensor, various applications are expected from space research to portable navigation systems.

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In order to fundamentally solve the potential safety hazard caused by the need to connect the electrical equipment to the high-voltage transformer, the application research of the power battery in the oilfield electrical equipment is organized, and the electrical equipment based on the power battery is developed, which realizes that the wellhead transformer can meet the power load demand of the whole operation process. The field application proves that the power battery can be applied to the electric operation equipment to realize the intrinsic safety of the equipment, and has good energy-saving and environmental protection effect. The novel electrical equipment is easy to operate, simple to maintain, and can be generalized and applied in oilfield.

Aiming at the accurate estimation of rotor speed and position of surface- mounted permanent synchronous motor, a scheme using extended state observer in the two phase static frame is constructed. The conventional method estimating the rotor speed and position in two phase synchronized rotation reference frame has the problem of error accumulation of the estimated rotor position which was calculated by angular velocity estimated value integral. This method avoids those problems and has advantages. The speed and current closed loop control system is constructed by using the auto disturbance rejection controller to replace the PI regulator. The simulation results validate the accuracy of the rotor speed and position is higher, and the system is stable and has good disturbance rejection performance.