| 摘要 |
An inverter for controlling drive of a motor mounted on an electrically powered vehicle is controlled based on pulse width modulation using a carrier signal. In order to lower electromagnetic noise, normally, a carrier frequency (f1) of the inverter is changed periodically or randomly within a first frequency range (420) set in advance, as the time elapses, While a vehicle speed is low, the carrier frequency (f1) is changed periodically or randomly within a second frequency range (430) set in advance to be wider than the first frequency range (420) and to be equal in central frequency (fa) to the first frequency range (420), as the time elapses. The second frequency range (430) is set to include a resonant frequency (frm) of a specific mechanical oscillation system higher in electromagnetic noise generated at a natural resonant frequency, among a plurality of mechanical oscillation systems formed by equipment mounted on the electrically powered vehicle. On the other hand, the first frequency range (420) is set not to include the resonant frequency (frm). |
