MITIGATION OF UNBALANCED INPUT DC FOR INVERTER APPLICATIONS

摘要

Mitigating the DC content of an AC output from an inverter is important for electrical system reliability. The inverter may be powered by unbalanced DC inputs while still mitigating the DC content of the AC output wavefrom. The present invention provides methods to mitigate the DC content in the output DC voltage by reshaping the PWM reference signals (carrier signals) according to the DC content in such a way that the DC content is canceled. These reshaped PWM reference signals may be, for example, unsymmetrical reference waveforms. Unlike conventional methods for providing an AC voltage from a DC voltage with an inverter, which may result in DC content in the output AC voltage when an unbalanced DC input voltage is supplied, the present invention provides methods for mitigating the DC content in an AC voltage, even if the inverter providing the AC voltage is supplied with unbalanced DC voltage.