Switching power supply control method and device and switching power supply

The invention relates to the technical field of power supply control, and discloses a switching power supply control method and device and a switching power supply, and the method comprises the following steps: obtaining the output voltage of the switching power supply through a sampling circuit which comprises a drain resistor RA and a sampling resistor RS; a support vector machine algorithm is adopted, a voltage sample is projected to a high-dimensional space for fitting, an optimal separation hyperplane is trained for classification regression, and obtained output voltage is analyzed in real time; and adjusting the switching frequency or duty ratio of the switching power supply according to the output of the algorithm, thereby realizing the accurate control of the output voltage. According to the switching power supply control method and device and the switching power supply, the output voltage of the switching power supply is analyzed in real time by adopting an algorithm based on machine learning, and th