Oil pumping unit load-loss protection suspension center following method and system

The invention relates to the technical field of oil pumping units, in particular to an oil pumping unit load-loss protection suspension point following method and system, and the method comprises the steps: controlling a polish rod to operate at a preset operation speed in an operation mode; judging whether the running state of the oil pumping unit is an off-load running state or not according to the relative value of the running speed of the polish rod and the preset running speed and the polished rod load parameters, and if the off-load running state is judged, entering a learning mode; in the learning mode, the running speed of the polish rod is periodically increased by adjusting the running speed of the polish rod to the lowest running speed; and recording the running speed of the polish rod in the previous period when the learning mode is finished and running the polish rod at the speed until the running state of the oil pumping unit in a certain period is an off-load running state. According to the met