Back to results
US 7,193,387 B1Granted
System and method for motor speed estimation using hybrid model reference adaptive system
AssigneeRockwell Automation Technologies, Inc.
InventorsHaihui Lu, Wei Qian
Life of this patent
Estimating the term…
Abstract
Motor drives, motor speed controllers, motor speed estimation systems, and methods are presented for controlling motor startup speed and for estimating motor speed during startup, in which a speed estimate controller provides a rotor speed estimate based on a first error term from a torque-based MRAS component for a first range of motor speeds and based on a second error term from a rotor flux-based MRAS component for a second range of speeds.
Claims20
An AC motor drive system for operating an AC induction motor, the motor drive system comprising:
- a switching system including a plurality of switching devices coupled between an AC power source and an induction motor, the individual switching devices operative to selectively couple a corresponding motor lead to the AC power source according to a corresponding switch control signal;
- and
- a motor startup control system for controlling the motor speed during startup, the motor startup control system comprising:
- a hybrid model reference adaptive system (MRAS) component including:
- a torque-based MRAS component providing a first error term representing a difference between a calculated torque value and an estimated torque value;
- and
- a rotor flux-based MRAS component providing a second error term representing a difference between a calculated rotor flux and an estimated rotor flux;
- a speed estimate controller providing a rotor speed estimate according to a controller error input;
- a motor controller providing a motor controller output for controlling the motor speed during startup according to a desired startup speed profile and according to the rotor speed estimate;
- a switch control circuit providing a plurality of switch control signals to control operation of the switching devices of the switching system during startup of the motor according to the controller output;
- and
- an error selector operatively coupled with the hybrid MRAS component and with the speed estimate controller to provide the error input to the speed estimate controller, the error selector providing the first error term as the controller error input when the rotor speed estimate is less than or equal to a first threshold and providing the second error term as the controller error input when the rotor speed estimate is greater than the first threshold.
9 more elements
A startup control system for controlling the speed of an electric motor during startup, comprising:
- a speed estimate controller providing a rotor speed estimate according to a controller error input;
- a hybrid model reference adaptive system (MRAS) component, including a torque-based MRAS component providing a first error term representing a difference between a calculated torque value and an estimated torque value, and a rotor flux-based MRAS component providing a second error term representing a difference between a calculated rotor flux and an estimated rotor flux;
- an error selector operatively coupled with the hybrid MRAS component and with the speed estimate controller to provide the error input to the speed estimate controller, the error selector providing the first error term as the controller error input when the rotor speed estimate is less than or equal to a first threshold and providing the second error term as the controller error input when the rotor speed estimate is greater than the first threshold;
- and
- a motor controller providing a controller output for controlling the motor speed during startup according to a desired startup speed profile and according to the rotor speed estimate.
2 more elements
A hybrid model reference adaptive system (MRAS) motor speed estimation system for estimating the speed of an electric motor, comprising:
- a speed estimate controller providing a rotor speed estimate according to a controller error input, the controller including at least one gain factor that is adjusted at least in part according to a stator flux modulus or a rotor flux modulus;
- a torque-based MRAS component providing a first error term representing a difference between a calculated torque value and an estimated torque value;
- a rotor flux-based MRAS component providing a second error term representing a difference between a calculated rotor flux and an estimated rotor flux;
- and
- an error selector providing the error input to the speed estimate controller according to the first error term when the rotor speed estimate is in a first speed range and providing the error input according to the second error term when the rotor speed estimate is in a second speed range.
2 more elements
A method of controlling the speed of an electric motor, the method comprising:
- providing a rotor speed estimate according to a controller error input;
- providing a controller output according to the rotor speed estimate and according to a desired speed profile;
- controlling the motor speed according to the controller output;
- computing a first error term as the difference between a calculated torque value and an estimated torque value;
- computing a second error term as a vector product of a calculated rotor flux and an estimated rotor flux;
- and
- providing the controller error input according to the first error term when the rotor speed estimate is in a first speed range and providing the error input according to the second error term when the rotor speed estimate is in a second speed range.
4 more elements
Dependencies are inferred from the claim text.