Fault diagnosis and automatic fault tolerance system and method

The invention provides a fault diagnosis and automatic fault tolerance system and method. The system comprises a main control module and N control modules, the control module is used for detecting whether the buck converter has a fault and detecting the fault type according to the switching state and the voltage value; when it is detected that the buck converter works normally, a first control signal is sent to the main control module; the main control module is used for calculating a working current instruction and a staggered conduction angle of each buck converter according to the number M of the received first control signals; the working current instruction and the interlaced conduction angle are sent to a control module which outputs a first control signal; and the M control modules are also used for forming a new daisy chain communication structure according to the working current instruction and the staggered conduction angle, driving the buck converter to work, rapidly positioning a fault, isolating