Motor tracking control system
AssigneeSeiberco Incorporated
InventorsHung D. Vu, Ralph W. Horber
Life of this patent
Estimating the term…
Abstract
An electronic circuit and software control methodology tracks motor position in a motor drive system. High power consumption position transducers, such as inductive sensors or optical encoders, can be controlled in a variable active duty cycle mode to reduce power and yet maintain motor position information while the main power is off. A lower power battery backup circuit is implemented as a secondary power source, and is automatically brought in operation when the main power supply is disabled. A dedicated control circuit operates during AC power outages, and the circuit average power can be controlled to a minimal rate, based on the rate of change of motor position. The motor can be externally driven, up to a defined limit speed, without losing its actual position information.
Claims29
A control system for the continuous, non-volatile tracking of the position of a motor armature, comprising:
- motor armature position data acquisition and storage means, including an armature position transducer, at least one electronic data processing unit, and sampling means for causing said electronic data processing unit to intermittently access said position transducer, for defined time periods and at controlled variable frequency of access;
- a primary power supply circuit for delivering drive current to the motor;
- a battery-powered secondary circuit;
- and
- means for operatively connecting said primary power supply circuit to said data acquisition and storage means, and for connecting, automatically and only upon disruption of power in said primary power supply circuit, said secondary circuit to said data acquisition and storage means to provide a backup operating mode;
- said frequency of access caused by said sampling means in said back-up mode varying in a direct relationship to the speed of the motor armature, as detected by said position transducer.
A method for the continuous, non-volatile tracking of the position of a motor armature utilizing a control system comprised of motor armature position data acquisition and storage means, including an armature position transducer, at least one electronic data processing unit, and sampling means for causing said electronic data processing unit to intermittently access the position transducer, for defined time periods and with a controlled variable frequency of access;
- and a battery-powered secondary circuit, comprising the steps:
- operatively connecting to said data acquisition and storage means a primary power supply circuit used for delivering drive current to the motor;
- automatically, and only upon disruption of power in said primary power supply circuit, operatively connecting said secondary circuit to said data acquisition and a storage means, to provide a back-up operating mode;
- and
- causing the frequency of access of said data acquisition and storage means by said sampling means in said back-up mode to vary in a direct relationship to the speed of the motor armature, as detected by said position transducer.
A control system for tracking the position of a motor armature, comprising motor armature position data acquisition and storage means, including an armature position transducer, at least one electronic data processing unit, and sampling means for causing said electronic data processing unit to intermittently access said position transducer, for defined time periods and at controlled frequency of access, said position transducer comprising first and second inductive sensors, one of said inductive sensors being configured to generate a first signal set and the other of said sensors being configured to generate a second signal set, each of said signal sets consisting of two sinusoidal signals that are 90° out of phase with one another and that represent sine and cosine functions from which the angle of the shaft of a motor can be determined, said fist signal set representing a minimal whole number of electrical cycles of said two signals and said second signal set representing a multiple whole number of said minimal number of said electrical cycles, said first and second sensors being selectively accessible by said electronic data processing means by way of said sampling means.
Dependencies are inferred from the claim text.