Rejection of undesirable effects of input DC-voltage ripple in single-phase PWM inverters

A new technique to cancel the effects of the ripple in the input DC-voltage of single-phase full-bridge voltage-source PWM inverters is discussed. From the analysis of the inverter output voltage, it is shown that its harmonic components are considerably affected by the input DC-voltage ripple, when the same PWM control scheme as for a constant input voltage is used. More precisely low order harmonics appear in the output voltage which are difficult to filter. With the new proposal based on the notion of conversion function, it is possible to reject all the low order harmonic components of the output voltage. Trade-offs involved in acquiring the immunity to DC-link voltage ripple are also discussed. Selected experimental results are presented. They show good concordance with expected results.