Control and current sampling method for brush direct current motor

The invention provides a control and current sampling method for a brush direct current motor, and the method comprises the following steps: S1, calculating the duty ratio of A-phase PWM and B-phase PWM according to a modulation coefficient, and carrying out the phase shift modulation of the duty ratio; s2, the modulated PWM controls an MOS tube of an H bridge in a pre-driving mode, and a brush direct current motor is driven to rotate forwards or reversely; s3, sampling the current of the motor through an Rs sampling resistor while driving the motor; on the basis of low-side single-resistor sampling, small current is effectively sampled in a PWM phase shift mode, so that current sampling of a full modulation area is achieved, the requirement for devices is low, and cost is low. 本发明提供了一种有刷直流电机的控制和电流采样方法，包括以下步骤：S1、根据调制系数计算出A、B相PWM的占空比，并对其进行移相调制；S2、经调制后的PWM经预驱控制H桥的MOS管，驱动有刷直流电机的正转或反转；S3、在驱动电机的同时，通过Rs采样电阻对电机电流进行采样；本发明基于低边单电阻采样，通过PWM移相的方式对小电流进行有效采样，从而实现了全调制区的电流采样，对器件的要求低、成本低。