Current Sensor Fault-Tolerant Operation of Dual Traction Inverters using Six-Phase Current Reconstruction Technique

Fault-tolerant operation of dual traction inverters is vital to reliability of the propulsion system in hybrid electric vehicles (HEVs). This paper presents a six-phase current reconstruction technique for dual traction inverters in case of the failure of phase current sensors. With an extra current sensor installed in the DC link, missing phase currents can be derived from the DC-link current by applying the proposed phase shift strategies to the driver signals. All the current sensor failure scenarios and their corresponding phase shift schemes for current reconstruction are considered. With the proposed current reconstruction scheme, current sensor fault-tolerant operation of dual traction inverters is achieved. Even in the worst case when all the phase currents are missing, the maximum allowable modulation index demonstrates slight degradation. Simulation results are provided to verify the effectiveness of the proposed scheme.