An adaptive, observer-based switching method for B4 inverters feeding three-phase induction motors

摘要

A four-switch inverter called the B4 inverter is areconfigured topology of a B6 inverter, one leg of which isdamaged. The four-switch topology provides the overallsystem with fault-tolerant characteristics. However, thisreconfiguration will not only change the system dynamicsbut also degrade the system performance. For overcomingwith these issues, this paper presents an adaptive switchingmethod based on DC-link voltage control. In theproposed method, the selection of active vectors and thecalculation of switching times are made according to anadaptive, observer-based algorithm which will reduceDC-link voltage oscillations and adjust unbalancedcurrents fed to induction machines. In this algorithm, anonline, designed observer is utilized so as to estimate theDC amount of the DC-link voltage. Applying this method,we will decrease flux and torque ripples as well as increasethe inverter efficiency and performance. The simulationresults presented in the MATLAB environment evaluateand validate the performance and effectiveness of thisapproach.