The use of modulation theory to calculate the harmonic distortion in HVDC systems operating on an unbalanced supply

This paper describes a means of calculating harmonic distortion due to a HVDC power converter operating on a nonideal supply. The switching functions of a power converter system are derived including the effects of an unbalanced supply and unbalanced AC side impedance. The paper describes how the functions can be used in the calculation of harmonic and interharmonic currents in HVDC and similar power systems.