| 摘要 |
PURPOSE:To reduce electromagnetic noise while suppressing reactive power by driving a plurality of motor drive transistors such that the transient state of motor drive transistors for adjoining phases laps over for a predetermined time between the conducting period and the non-conducting period of the transistor. CONSTITUTION:Sensor signals HU<+>, HU<-> having 180 deg. phase difference are fed to the bases of transistors(Tr) Q7, Q8. Assuming currents flowing through TrQ7, Q8 are I7, I8 and base-emitter voltages thereof are VBE7, VBE8, they satisfy formula 1. Maximum value of current flowing through the TrQ7, Q8 is the current value I0 of a power source CS1. Current flowing through a TrQ9 has maximum value 2XI0 when the current I0 flows through both V-shape transistor Q15 and the TrQ7. A power TrQ4 is driven by half-wave drive current flowing through a TrQ1 and feeds current to three-phase input U. By such arrangement, reactive power can be suppressed sufficiently when the phases are switched and counter electromotive force and electromagnetic noise are also suppressed. |
