Carrier-Based PWM Technique and Extended State Observer-Based Current Control Scheme for Current-Source Inverter-Fed Five-Phase PMSM Drives

Current-source inverter (CSI) is considered as a promising candidate for future permanent-magnet synchronous machine (PMSM) drives, for its superior harmonic attenuation and higher reliability. In this article, the control scheme for five-phase CSI-fed PMSM drive system is investigated. First, a carrier-based pulse-width modulation (PWM) technique is proposed for five-phase CSI. From the perspective of space vector mapping, a comparison is presented between the three-value ternary and the two-value binary switching functions, which are suitable for the current-source and voltage-source inverter topologies, respectively. The derivation procedure of switching pattern in five-phase CSI is proposed including logic conversion, phase correction, and zero state assignment. Besides the modulation technique, a current control approach based on the extended state observer is proposed. The parallel resonance of filtering capacitor and winding inductance can be suppressed by feeding back the estimation of differential state. The uncertainties and disturbances in the plant can be compensated by the estimation of extended state. The s-domain modeling of current controller is presented and the key parameter design approach is proposed in consideration of stability performance. Experiments are performed to validate the proposed control schemes.