Bus capacitor bank configuration for a regenerative drive

A method for buffering energy in a regenerative elevator drive device, the regenerative elevator drive device including a inverter having a plurality of power components and a converter having a plurality of power components, the method comprising:

• providing a direct current (DC) link bridging the inverter and the converter, the DC link comprising:
• one or more internal capacitors bridging the inverter and the converter for energy buffering;
• an external capacitor in parallel with the one or more internal capacitors for energy buffering, wherein the capacitance of the external capacitor is greater than the capacitance of at least one of the one or more internal capacitors;
• and
• an inductor located directly between the external capacitor and the one or more internal capacitors.

An elevator system, comprising:

• an elevator car disposed in a hoistway;
• a motor operatively connected to the elevator car, the motor generating a thrust force to move the elevator car within the hoistway;
• a power source operatively connected to the motor, the power source supplying power to the motor;
• and
• a regenerative elevator drive device operatively connected to the power source and the motor, the regenerative elevator drive device comprising:
• an inverter having a plurality of power components;
• a converter having a plurality of power components;
• and
• a direct current (DC) link bridging the inverter and the converter, the DC link comprising:
• one or more internal capacitors bridging the inverter and the converter;
• an external capacitor in parallel with the one or more internal capacitors, wherein the capacitance of the external capacitor is greater than the capacitance of at least one of the one or more internal capacitors;
• and
• an inductor located directly between the external capacitor and the one or more internal capacitors.