A method for operating a power conversion system, the method comprising: operating a rectifier of the power conversion system in a boost mode to provide a DC bus voltage, Vdc, at a DC bus higher than a peak line to line AC input voltage value, wherein the rectifier is receiving AC power from an external power source through a filter circuit; determining a filter magnetic derating value characterizing the safe operating point with respect to thermal stress on the inductor core structures of the filter circuit according to a line to line AC input voltage value and according to a DC bus voltage boost amount, the filter magnetic derating value being less than or equal to a maximum output current rating for the rectifier; determining a space vector pulse width modulation derating value associated with rectifier switching losses according to the DC bus voltage boost amount, the space vector pulse width modulation derating value being less than or equal to the maximum output current rating for the rectifier; comparing the filter magnetic derating value to the space vector pulse width modulation derating value; providing (114, 120) pulse width modulated rectifier switching control signals to at least one switching device (S1-S6) of the rectifier using discontinuous pulse width modulation, DPWM, if the filter magnetic derating value is greater than the space vector pulse width modulation derating value; and providing (118, 120) pulse width modulated rectifier switching control signals to the at least one switching device (S1-S6) of the rectifier using space vector pulse width modulation, SVPWM, if the space vector pulse width modulation derating value is greater than the filter magnetic derating value. operating a rectifier of the power conversion system in a boost mode to provide a DC bus voltage, Vdc, at a DC bus higher than a peak line to line AC input voltage value, wherein the rectifier is receiving AC power from an external power source through a filter circuit; determining a filter magnetic derating value characterizing the safe operating point with respect to thermal stress on the inductor core structures of the filter circuit according to a line to line AC input voltage value and according to a DC bus voltage boost amount, the filter magnetic derating value being less than or equal to a maximum output current rating for the rectifier; determining a space vector pulse width modulation derating value associated with rectifier switching losses according to the DC bus voltage boost amount, the space vector pulse width modulation derating value being less than or equal to the maximum output current rating for the rectifier; comparing the filter magnetic derating value to the space vector pulse width modulation derating value; providing (114, 120) pulse width modulated rectifier switching control signals to at least one switching device (S1-S6) of the rectifier using discontinuous pulse width modulation, DPWM, if the filter magnetic derating value is greater than the space vector pulse width modulation derating value; and providing (118, 120) pulse width modulated rectifier switching control signals to the at least one switching device (S1-S6) of the rectifier using space vector pulse width modulation, SVPWM, if the space vector pulse width modulation derating value is greater than the filter magnetic derating value.