Recently, considerable interest has been
focused on the development of direct AC-AC
(matrix) converters for variable speed induction
motor drives. The converter is capable of
operating at lagging, unity or even leading
fundamental input displacement factor. The
converter offers the advantages of fourquadrant
operation, sinusoidal input and output
waveforms, minimum energy storage
components and controllable displacement
factor. Despite the inherent: advantages of the
matrix converter, its physical realisation is not
straighlforward due primarily to the absence of
naturally occurring freewheeling paths.
Consequently, the timing of the switch actuation
signals is particularly critical and protection of
the circuit under fault conditions requires very
careful consideration. Another disadvantage of
the converter is that the maximum output
voltage is limited to 86.6 per cent of the input
voltage[4].
A three interval pulse width modulation ( PWM )
has been developed which allows the
implementation of the control algorithm. For the
benefit of a good sinusoidal open-foop output
voltage modulation a compensation of the 5ith
and 7" order voltage harmonics resulting from
the input current modulation has been added