Current control in matrix converters connected to polluted AC voltage supplies

The matrix converter features natural bidirectional power flow, sinusoidal current/voltage waveforms, and a reduced size and weighty compared to standard direct static power converters. However, it is sensitive to polluted AC supplies because no storing elements are present and thus any disturbance would reach the load terminals. Typical disturbances in the AC distribution systems are voltage unbalances, sags, swells, and 5^th & 7^th voltage harmonics are also found when nonlinear loads are present in the distribution system. This paper presents a comparison between a classical control strategy such as Venturini modulation with linear current controllers and a proposed predictive control approach for the load currents. The proposed method results easy to implement in digital systems and behaves - in combination with the power topology - as a buffer for the pollution in the AC mains. Simulated and preliminary experimental results show that the proposed strategy achieves sinusoidal load currents even under AC voltage unbalances, sags, swells, and 5^th & 7^th voltage harmonics.