Energy savings with optimized motion profiles
AssigneeOtis Elevator Company
InventorsRichard N. Fargo, Richard K. Pulling
Life of this patent
Estimating the term…
Abstract
An elevator system includes a car, a hoist motor for elevating and lowering the car, a brake for limiting car movement, an input device for selecting a destination for a run, and a controller. The controller receives a command from the input device and controls operation of the hoist motor and the brake. The controller has a loss reduction mode wherein the controller selects a velocity profile for the run that varies according to car load, run direction, and run distance to reduce a combined set of energy losses for the run.
Claims15
An elevator system comprising:
- a car;
- a hoist motor for elevating and lowering the car;
- a brake for limiting car movement;
- an input device for selecting a destination for a run;
- and
- a controller for receiving a command from the input device and for controlling operation of the hoist motor and the brake, wherein the controller has a loss reduction mode wherein the controller selects a velocity profile for the run that varies according to car load, run direction, and run distance to reduce a combined set of energy losses for the run;
- wherein the combined set of energy losses is substantially minimized within a set of constraints in the loss reduction mode;
- wherein the set of constraints includes limits on velocity, acceleration, jerk, and time for the run.
An elevator system comprising:
- a car;
- a hoist motor for elevating and lowering the car;
- a brake for limiting car movement;
- an input device for selecting a destination for a run;
- and
- a controller for receiving a command from the input device and for controlling operation of the hoist motor and the brake, wherein the controller has a normal mode that selects a first velocity profile for the run and a loss reduction mode that selects a second velocity profile for the run, wherein the second velocity profile uses less energy for the run than that of the first velocity profile, and wherein the second velocity profile has greater maximum jerk magnitude than the first velocity profile;
- wherein jerk at the beginning and jerk at the end of the first velocity profile have magnitudes greater than jerk at the beginning and jerk at the end of the second velocity profile, respectively.
A method for operating an elevator, the method comprising:
- receiving a command for a run in an elevator car;
- selecting a velocity profile as a function of run direction, run distance, and car load to reduce a combined set of energy losses for that run;
- and
- controlling motion of the elevator car according to the selected velocity profile;
- wherein selecting a velocity profile includes determining the combined set of energy losses for a plurality of potential velocity profiles based upon the run direction, run distance, and car load prior to selecting the velocity profile;
- wherein determining the combined set of energy losses includes:
- determining copper and iron energy losses for a permanent magnet motor to move the elevator car over the course of the run;
- determining energy losses to operate a brake over the course of the run;
- determining switching energy losses to operate an elevator drive over the course of the run;
- and
- calculating the combined set of energy losses to include losses for the permanent motor, the brake, and the elevator drive.
Dependencies are inferred from the claim text.