Control strategy of matrix converters

The author describes a new control strategy for a matrix converter that transforms an N-phase system with frequency f₁ directly to an M-phase system with frequency f₂. In this converter each branch can conduct current in both directions and can be switched on and switched off by semiconductor power electronic devices in an arbitrary time instant. This control strategy is mathematically described by relationships between state functions that determine the state of each converter branch. It is proved that this strategy keeps symmetry in both input and output systems of voltages and currents. Reinterpretation of the state functions as functions of two variables and its geometrical representation is shown, which leads to a very simple determination of the time instants of the state changes of each converter branch. As an example, the time instants of state changes of all semiconductor power switching devices for a 3-phase to 3-phase frequency converter is determined