Effects of input voltage measurement on stability of matrix converter drive system

The effects of different input voltage measurement methods on the stability of a matrix converter drive system are analysed. In particular, with the aim of improving the maximum output power of the matrix converter, the duty cycles of the switching configurations are calculated using input voltages filtered by a digital lowpass filter. A variable state average model of the whole system, which takes into account the grid impedance, the input L–C filter parameters and the load, is used for the theoretical analysis. The stability of the system is evaluated by analysing the migration of eigenvalues of the system, which is linearised around a steady-state operating point. The analytical approach allows the determination of the maximum power for a stable operation of the matrix converter as a function of the time constant of the digital lowpass input voltage filter. Theoretical considerations are supported by simulation results, showing the varying behaviour of the matrix converter that can be achieved in terms of stability as the time constant of the digital filter is changed.