| 摘要 |
<p>21- OSH-2526 COMMUTATING CAPACITOR CHARGE DETECTION CIRCUIT AND METHOD A circuit and method is disclosed for detecting the presence of charges of appropriate magnitude and polarity on commutating capacitors of an inverter that converts a DC output current to a drive current of variable magnitude and frequency for driving an AC electric motor producing controllable rotation and torque. The presence of charges of appropriate magnitude and polarity is detected by measuring the voltages across the conduction controlled rectifying devices in the inverter. In addition, the existence of condition controlled rectifying devices in the conducting state is determined by measuring the magnitude of the DC output current. An output signal is generated when the charges of appropriate magnitude and polarity are detected, which output signal is effective to allow the inverter to generate normal drive current. The absence of the output signal is effective to force the magnitude of the DC output current below a predetermined magnitude value and is effective to prevent the sequencing of gating signals to the inverter, whereby the drive current is such that the motor produces substantially zero rotation at substantially zero torque.</p> |
