Finite states model predictive direct power control for phase leg faults tolerant operation of bidirectional AC/DC converter

Abstract

Based on the operation analysis of bidirectional AC/DC converter with leg faults, a power predictive model of four-switch three-phase (FSTP) in αβ coordinates is established. The finite states model predictive direct power control (MPDPC) method of fault-tolerant FSTP converter is designed for continuous operation, even if the phase leg of bidirectional AC/DC converter has a fault. According to the power predictive model and cost function, the optimal space voltage vector is selected to achieve flexible seamless switching between inverter and rectifier mode with direct power control. DC-link split capacitor voltage balance control is achieved by injecting a dc bias current into the faulty phase current. The proposed method does not need pulse width modulation signals and current control loop. It has the advantages of only minor calculations are required and it is easy to be implemented. The simulation and experiment results show good steady state and dynamic performance of proposed control method for bidirectional AC/DC converter with leg faults.