Drive system with common DC bus

A method comprising:

• electrically connecting a first switching assembly associated with a first inverter to a common DC bus and to a pre-charge circuit;
• electrically connecting a second switching assembly associated with a second inverter to the common DC bus and to the pre-charge circuit;
• electrically connecting a local DC bus of the first inverter to the common DC bus;
• operating the second switching assembly associated with the second inverter to electrically connect a local DC bus of the second inverter to the pre-charge circuit while the local DC bus of the first inverter is electrically connected to the common DC bus;
• comparing a voltage of a capacitor network electrically connected to the local DC bus of the second inverter to a threshold voltage while the local DC bus of the first inverter is electrically connected to the common DC bus;
• and
• determining whether to disconnect the local DC bus of the second inverter from the pre-charge circuit and whether to connect the local DC bus of the second inverter to the common DC bus based on the comparison.

A system comprising:

• a pre-charge circuit configured to produce direct current (DC) electrical power;
• a common DC bus;
• and
• a plurality of inverters, each inverter comprising:
• a local DC bus, a capacitor network electrically connected to the local DC bus, and an electrical network electrically connected to the local DC bus, the electrical network configured to generate an alternating current (AC) drive signal, and wherein the capacitor network of each inverter is configured to be electrically connected to the common DC bus or the pre-charge circuit via a switching network, the pre-charge circuit is single pre-charge circuit configured to be electrically connected to the capacitor network of any of the plurality of inverters, and the pre-charge circuit is configured to provide the DC electrical power to the capacitor network and the local DC bus of at least one of the plurality of inverters while the local DC bus of at least one other of the plurality of inverters is electrically connected to the common DC bus.

A system comprising:

• a pre-charge circuit configured to produce direct current (DC) electrical power;
• a common DC bus;
• a plurality of inverters, each inverter comprising:
• a local DC bus;
• a capacitor network connected to the local DC bus;
• and an electrical network connected to the local DC bus, the electrical network configured to generate an alternating current (AC) drive signal;
• and
• a plurality of switching assemblies, each switching assembly being associated with one of the plurality of inverters, and each switching assembly configured to electrically connect the local DC bus and the capacitor network of the associated inverter to one of:
• (i) the common DC bus and (ii) the pre-charge circuit, wherein the pre-charge circuit is a single pre-charge circuit configured to electrically connect to the local DC bus and capacitor network of any of the plurality of inverters, the pre-charge circuit is an auxiliary pre-charge circuit, and the system further comprises a common pre-charge circuit electrically connected to the common DC bus, and wherein the common pre-charge circuit is configured to provide a DC pre-charge current to all of the capacitor networks while the capacitor networks are electrically connected to the common DC bus.

A system comprising:

• a pre-charge circuit configured to produce direct current (DC) electrical power;
• a common DC bus;
• and
• a plurality of inverters, each inverter comprising:
• a local DC bus, a capacitor network electrically connected to the local DC bus, and an electrical network electrically connected to the local DC bus, the electrical network configured to generate an alternating current (AC) drive signal, and wherein the capacitor network of each inverter is configured to be electrically connected to the common DC bus or the pre-charge circuit via a switching network, the pre-charge circuit is single pre-charge circuit configured to be electrically connected to the capacitor network of any of the plurality of inverters, the pre-charge circuit is an auxiliary pre-charge circuit, and the system further comprises a common pre-charge circuit electrically connected to the common DC bus, and the common pre-charge circuit is configured to provide a DC pre-charge current to all of the capacitor networks while the capacitor networks are electrically connected to the common DC bus.