| 摘要 |
<p>A variable speed drive (VSD) for heating, ventilation, air-conditioning and refrigeration (HVAC & R) applications includes a variable speed drive system configured to receive an input AC voltage at a fixed AC input voltage and provide an output AC power at a variable voltage variable frequency. The variable speed drive includes a converter stage connected to an AC power source providing the input AC voltage, the converter stage being configured to convert the input AC voltage to a boosted DC voltage; a DC link connected to the converter stage, the DC link being configured to filter and store the boosted DC voltage from the converter stage; and an inverter stage connected to the DC link, the inverter stage being configured to convert the boosted DC voltage from the DC link into the output AC power having the variable voltage and the variable frequency. The variable speed drive also includes a ground fault protection system for interrupting fault current flowing to an input phase of the active converter, the ground fault on an input phase of the active converter, and the controller; wherein the active converter further includes at least two semiconductor switches for each power phase of the AC power source; each of inversely connected to switch in parallel, wherein each of the reverse lGBTs inversely connected to switch the RB IGBTs to a nonconductive state in response to a sensed ground fault current.</p> |
