Inverter control circuit of motor-driven blower for electric vacuum cleaner, drive control circuit using the same, and electric vacuum cleaner using drive control circuit

The present application is based on Japanese Priority Documents 2000-258763 filed on Aug. 29, 2000 and 2001-251943 filed on Aug. 22, 2001, the content of which is incorporated herein by reference. An electric vacuum cleaner including a motor-driven blower driven by an inverter circuit. The inverter circuit has a plurality of switching elements. The inverter circuit AC-drives a motor-driven blower according to periodic switching between the switching elements. The periodic switching is based on the detected value of physical quantities related to the electric vacuum cleaner. The electric vacuum cleaner can, in the highest operation mode, undergo a sudden fluid load variation. The electric vacuum cleaner is able to limit, by way of the inverter circuit, the unpleasant sound produced by the vacuum cleaner due to the change in rotation velocity of a rotor of a motor of the vacuum cleaner.