Patent ID: 8590672

Claim:
A method for managing power in an elevator system including an elevator hoist motor, a primary power supply, and an electrical energy storage (EES) system, the method comprising: determining a power demand of the elevator hoist motor; determining a state-of-charge (SOC) of the EES system; and controlling power exchanged between the hoist motor, the primary power supply, and the EES system based on the power demand of the hoist motor and the SOC of the EES system; wherein, when the power demand of the elevator hoist motor is negative, the controlling step comprises: storing all energy generated by the elevator hoist motor in the EES system if the SOC of the EES system is below a minimum threshold SOC; delivering all energy generated by the elevator hoist motor to the primary power supply if the SOC of the EES system is above a maximum threshold SOC; and distributing the energy generated by the elevator hoist motor between the primary power supply and the EES system when the SOC of the EES system is between the minimum threshold SOC and the maximum threshold SOC, wherein the energy is distributed in a ratio that is a function of the SOC of the EES system.