Low-frequency dynamic modelling and control of matrix converter for power system applications

High-power density of a matrix converter (MC) necessarily introduces tight dynamic input–output coupling, which complicates controller design for high bandwidth applications. Strong contemporary interest in MC-based solutions for synchronous, power system applications demands high dynamic performance out of the MC, operated as a closed-loop system. The requisite system models reported either treat the MC – with its input and output filters – as a ‘black-box’ characterised by a set of eigenvalues, derived from linearised analysis around an equilibrium point. Alternatively, large-signal system analysis was reported for a feed-forward control approach with prescription of a throughput power boundary for stable operation. This study provides a designer's insight into MC modelling, based on linearised analysis, clearly establishing the influence of individual physical sub-systems on the overall dynamic performance. Onset of a cluster of right-half zeros, decided solely by the input filter, power factor, source voltage and power throughput, is shown to be the only factor threatening closed-loop stability. Subsequently, a controller with output feedback is designed to ensure stable operation well beyond the throughput power limit prescribed earlier. Comprehensive simulation and experimental results are provided to validate the analytical model and controller design.