Research On Down-hole Driver Of Electrical Submersible Progressing Cavity Pump Servo System Based On Finite Element Thermal Analysis

It is always an important research subject in oil industry to develop the high efficient and energy-saving petroleum production. Electrical submersible progressing cavity pump shows up and has wide foreground because of its better adaptability and lower energy dissipation than other artificial lift technique. Based on the characters that AC servo system has big torque in low velocity and wide velocity modulation region, the direct-driven Electrical submersible progressing cavity pump with high control accuracy and intelligence level was put forward in this paper and the down-hole driver for severe environment with high pressure and temperature in oil well, what was significant for enhancing the life and reliability of the whole system.Design the structure of the down-hole driver combined with the whole system requires and the severe environment. A special magnetic rotary encoder was designed using non-magnetic materials with low magnetic conductivity, which realized the angular displacement detected for the permanent magnet synchronous submersible motor. With the epoxy resin perfusion technology, the down-hole driver and motor was sealed and conducted by designing the high pressure sealing components. The thermal slug structure was determined by contrasting and analyzing the different thermal slug program. The thermal slug structural parameters that could influence the down-hole driver heat dissipation were analyzed, and finally optimized to get maximum heat transfer area.The simplified down-hole driver model was obtained through simplifying the connections and inner hardware circuit. A kind of IPM physical model establishing method was proposed according to the ANSYS analysis based on the practical heat resistance to perfect the simplified model. Deduce the natural convection control equation in limited space, the mathematic model of down-hole driver for analyzing three-dimensional temperature field was established. ANSYS/FLOTRAN software was used to solve the temperature field and others, and the influence of different parameters including heat transfer area, structural parameters and heater position. The better heat dissipation down-hole driver structure was finally confirmed.The experiment platform was established to measure the temperature and other electric parameters near four corners of IPM and simulate the temperature field in servo control cabinet. The simulation results demonstrated the rationality of the IPM physical model establishing method. Finally, the down-hole driver prototype, the permanent magnet synchronous submersible motor and the progressing cavity pump were assembled to build the ground temperature measuring experiment platform. Then the temperature fields of the simplified model were simulated for different operating modes. The results demonstrated the rationality and accuracy of the simulation analyze.