초록 ▼

An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, i

An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.

대표청구항 ▼

[ We claim:] [1.] A method of controlling a three-phase induction motor including a three-phase stator and rotor using direct vector control at all rotor speeds including zero speed, the method comprising the steps:transforming stationary reference frame three-phase stator current components to stat

[ We claim:] [1.] A method of controlling a three-phase induction motor including a three-phase stator and rotor using direct vector control at all rotor speeds including zero speed, the method comprising the steps:transforming stationary reference frame three-phase stator current components to stationary reference frame orthogonal two-phase current components;transforming stationary reference frame three-phase stator voltage components to stationary reference frame orthogonal two-phase voltage component;estimating a first set of orthogonal stator flux components from the stationary reference frame orthogonal two-phase current components and a null rotor speed;estimating a second set of orthogonal stator flux components from the stationary reference frame orthogonal two-phase current components and stationary reference frame orthogonal two-phase voltage components;using the first set of orthogonal stator flux components in direct vector control of the induction motor while the rotor is substantially static; and,using the second set of orthogonal stator flux components in direct vector control of the induction motor while the rotor is substantially dynamic.