| 摘要 |
PURPOSE:To prevent a phase short circuit by measuring an ideal gate signal, output phase voltage of an inverter, a current direction by a counter, detecting the direction of the current, measuring difference between the gate signal and the phase voltage, and delaying the phase voltage by the dead time. CONSTITUTION:An AC power source AC, a converter 1, an inverter main circuit 2 and a motor M are connected, and the motor M is driven and power regenerated. A phase voltage detecting comparator 3 detects the phase voltage signals Vu-Vw of the inverter 2. Ideal gate signals U-W from a PWM generator 4 are input to a dead time compensator 5 together with the signals Vu-Vw. The compensator 5 measures, determines positive or negative of phase currents Iu-Iw inverted according to whether the motor M is in a driving mode or a regenerative mode, difference between the signals U-W and the signals Vu-Vw is counted to form compensation gate signals Uo-Wo, and a dead time is generated by a generator 6. The inverter 2 is controlled by the dead time through a base driver 7. Thus, it can effectively prevent an arm short circuit. |
