Electric power-assisted brake system control method, electric power-assisted brake system and automobile

The invention discloses an electric power-assisted brake system control method which is used for an electric power-assisted brake system and comprises the steps that first phase current and second phase current collected from a power-assisted motor are obtained; in at least one phase current amplitude window period, calculating a phase current amplitude ratio between the first phase current and the second phase current, and judging whether the phase current amplitude ratio is within a preset amplitude ratio threshold range or not; if the phase current amplitude ratio exceeds the amplitude ratio threshold range, generating a fault signal; and controlling the power-assisted motor to stop working according to the fault signal. According to the invention, by calculating and judging the amplitude ratio of the two-phase current of the power-assisted motor collected in the sampling circuit of the electric power-assisted brake system, when the resistance value of the sampling resistor deviates, the fault can be ident