Coordinated fault-tolerant control method

A coordinated fault-tolerant control method for a power system with a plurality of two-stage power modules, each of the plurality of two-stage power modules comprising a front-stage circuit and a rear-stage circuit, the front-stage circuit having a DC midpoint, each of a first side circuit and a second side circuit of the rear-stage circuit comprising two rear-stage switch sets, each of the rear-stage switch sets comprising two switches in serial connection, the coordinated fault-tolerant control method comprising:

• when one switch in one of the two rear-stage switch sets in the first side circuit of the rear-stage circuit in a specified two-stage power module of the plurality of two-stage power modules fails, disabling the other switch in the rear-stage switch set with the failed switch;
• operating the other rear-stage switch set in the first side circuit of the rear-stage circuit in the specified two-stage power module in high-frequency switching;
• operating one of the two rear-stage switch sets in the second side circuit of the rear-stage circuit in the specified two-stage power module in high-frequency switching, and disabling the other of the two rear-stage switch sets in the second side circuit of the rear-stage circuit;
• and
• when any switch in the specified two-stage power module fails, controlling a potential of the DC midpoint in the specified two-stage power module to be regained balance.

A two-stage power module, comprising:

• a front-stage circuit having a DC midpoint;
• a rear-stage circuit electrically connected the front-stage circuit, wherein each of a first side circuit and a second side circuit of the rear-stage circuit comprises two rear-stage switch sets, and each of the rear-stage switch sets comprises two switches in serial connection;
• and
• a controller is configured to:
• when one switch in one of the two rear-stage switch sets in the first side circuit of the rear-stage circuit fails, disabling the other switch in the rear-stage switch set with the failed switch;
• operating the other rear-stage switch set in the first side circuit of the rear-stage circuit in high-frequency switching;
• operating one of the two rear-stage switch sets in the second side circuit of the rear-stage circuit, and disabling the other of the two rear-stage switch sets in the second side circuit of the rear-stage circuit;
• and
• when any switch in the two-stage power module fails, controlling a potential of the DC midpoint such that a current flowing the DC midpoint is essentially equal to zero.