Bond graph modeling and fault injection of CRH5 traction system

CRH5 electric multiple unit (EMU) traction system is a multi-domain mechatronical system with complex structure. Mechanisms on various faults or failures are not clear yet. To develop accurate system model for fault prognosis, diagnosis and propagation analysis, bond graph (BG) theory is adopted due to its unique ability in multi-domain modeling and clear cause-effect representation. With the aid of a commercial software (20-SIM), a BG topological structure model which contains inverter, motor and gearbox, and direct torque control (DTC) unit have been developed, where DTC control the stator flux and electromagnetic torque. Common faults in EMU traction system such as motor and sensor faults are injected into the BG model. Broken rotor bar fault in driving motors is simulated by increasing gradually the number of broken bars. Three kinds of speed sensor faults are also injected to analyze their influences to the whole traction system. The simulation results are well in accordance with real CRH5 traction systems. The developed model can provide a useful platform for the study and verification of fault prognosis, diagnosis and propagation methods.