Pumping units are the main production machinery in the oilfield, and the electrical energy consumed accounts for about 60% of the electrical energy consumed by the oilfield. The requirements of the pumping unit for the electric motor are large starting torque, high efficiency, and a wide economic operation range. If an induction motor is used, in order to meet the requirements of the large starting torque of the pumping unit, a large-capacity induction motor needs to be configured. However, the average load rate during normal operation is low, and the efficiency and power factor are low, resulting in a large amount of waste of electrical energy. Compared with induction motors, applying permanent magnet synchronous motors to pumping units has the following advantages:
① After the reasonable design, a large starting torque can be obtained. Therefore, a permanent magnet synchronous motor with a small frame size can be used to replace an induction motor with a frame size of 1 or 2 larger than that of the permanent magnet synchronous motor, which reduces the volume of the permanent magnet synchronous motor while increasing the load rate;
② High efficiency and high power factor can be obtained;
③ Wide range of economic operations.