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US 6,184,638 B2Granted
Control system for an induction motor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorYoshihiko Kinpara
Life of this patent
Estimating the term…
Abstract
An estimated rotation angular velocity □r0 and an estimated secondary resistance Hr0 are processed using a first feedback gain H1 under a condition that a first state deviation E1 is in phase with a quadrature component of an estimated secondary magnetic flux □r01. An estimated primary resistance Rs0 is processed using a second state deviation H2 under a condition that a second state deviation E2 is in phase with an estimated primary current 02. These values are used to control the speed of an induction motor without an angular velocity detector.
Claims17
A control system for an induction motor comprising:
- current detecting means for detecting a primary current of an induction motor;
- excitation-current command computing means for receiving a secondary magnetic flux command to be output by the induction motor, and processing an AC signal and a DC signal proportional to said secondary magnetic flux command, to thereby produce an excitation current command of the induction motor;
- torque control means for receiving a torque command to be output by the induction motor and said excitation current command, and processing said estimated rotation angular velocity, said estimated secondary resistance and said primary current, and said torque control means controlling a primary voltage of the induction motor so that an output torque of the induction motor follows said torque command;
- first parameter estimating means for processing estimated primary resistance, said primary voltage and said primary current of the induction motor, to thereby produce said estimated rotation angular velocity and said estimated secondary resistance;
- and
- second parameter estimating means for processing said estimated rotation angular velocity, said estimated secondary resistance, said primary voltage and said primary current, to thereby produce said estimated primary resistance,
- wherein
- said first parameter estimating means includes
- a) a first measuring unit for processing said estimated primary resistance, said estimated secondary resistance, said estimated rotation angular velocity, a first feedback gain, said primary voltage and said primary current, to thereby produce estimated secondary current, estimated secondary magnetic flux and first state deviation,
- b) a rotational-speed estimating unit for processing said first state deviation and said estimated secondary magnetic flux, which are derived from said first measuring unit, to thereby produce said estimated rotation angular velocity,
- c) a secondary-resistance estimating unit for processing said first state deviation and said estimated secondary current, which are derived from said first measuring unit, to thereby produce said estimated secondary resistance, and
- d) a first gain computing unit for processing said estimated rotation angular velocity derived from said rotational-speed estimating unit, to thereby produce said first feedback gain so that said first state deviation contains a component orthogonal to said estimated secondary magnetic flux, and
- said second parameter estimating unit includes
- a) a second measuring unit for processing said estimated primary resistance, said secondary resistance, said estimated rotation angular velocity, a second feedback gain, said primary voltage, and said primary current, to thereby produce an estimated primary current and a second state deviation,
- b) a primary-resistance estimating unit for processing said second state deviation and said estimated primary current, thereby produce said estimated primary resistance, and
- c) a second gain computing unit for processing said rotation angular velocity derived from said rotational-speed estimating unit, to thereby produce said second state deviation so that said first state deviation contains a component being in phase with said estimated primary current.
13 more elements
A control system for an induction motor comprising:
- current detecting means for detecting a primary current of an induction motor;
- excitation-current command computing means for receiving a secondary magnetic flux command to be output by the induction motor, and executing a process by use of said secondary magnetic flux command, to thereby produce an excitation current command of the induction motor;
- torque control means for receiving a torque command to be output by the induction motor and said excitation current command, and processing said estimated rotation angular velocity, said estimated secondary resistance and said primary current, and said torque control means controlling a primary voltage of the induction motor in accordance with the result of the processing so that an output torque of the induction motor follows said torque command;
- first parameter estimating means for processing estimated primary resistance, said estimated secondary resistance, said primary voltage and said primary current of the induction motor, to thereby produce said estimated rotation angular velocity;
- and
- second parameter estimating means for processing said estimated rotation angular velocity, said primary voltage and said primary current, to thereby produce said estimated primary resistance and said estimated secondary resistance
- wherein
- said first parameter estimating means includes
- a) a first measuring unit for processing said estimated primary resistance, said estimated secondary resistance, said estimated rotation angular velocity, a first feedback gain, said primary voltage and said primary current, to thereby produce an estimated secondary magnetic flux and a first state deviation,
- b) a rotational-speed estimating unit for processing said first state deviation and said estimated secondary magnetic flux, which are derived from said first measuring unit, to thereby produce said estimated rotation angular velocity,
- c) a first gain computing unit for processing said estimated rotation angular velocity derived from said rotational-speed estimating unit, to thereby produce said first feedback gain so that said first state deviation contains a component orthogonal to said estimated secondary magnetic flux, and
- said second parameter estimating unit includes
- a) a second measuring unit for processing said estimated primary resistance, said secondary resistance, said estimated rotation angular velocity, a second feedback gain, said primary voltage, and said primary current, to thereby produce an estimated primary current and a second state deviation,
- b) a primary-resistance estimating unit for processing said second state deviation and said estimated primary current, to thereby produce said estimated primary resistance, and
- c) a secondary-resistance estimating unit for processing said estimated primary resistance derived from said primary-resistance estimating unit, to thereby produce said estimated secondary resistance,
- d) a second gain computing unit for processing said rotation angular velocity derived from said rotational-speed estimating unit, to thereby produce said second state deviation so that said first state deviation contains a component being in phase with said estimated primary current.
13 more elements
A control system for an induction motor comprising:
- current detecting means for detecting a primary current of an induction motor;
- excitation-current command computing means for receiving a secondary magnetic flux command to be output by the induction motor, and processing an AC signal and a DC signal proportional to said secondary magnetic flux command, to thereby produce an excitation current command of the induction motor;
- torque control means for receiving a torque command to be output by the induction motor and said excitation current command, and processing said estimated rotation angular velocity, said estimated secondary resistance and said primary current, and said torque control means controlling a primary voltage of the induction motor so that an output torque of the induction motor follows said torque command;
- parameter estimating means for processing said primary voltage and said primary current of the induction motor, to thereby produce said estimated rotation angular velocity and said estimated secondary resistance,
- wherein
- said parameter estimating means includes
- a) a measuring unit for processing estimated primary resistance, said estimated secondary resistance, said estimated rotation angular velocity, a feedback gain, said primary voltage and said primary current, to thereby produce estimated secondary current, estimated secondary magnetic flux and state deviation,
- b) a rotational-speed estimating unit for processing said state deviation and said estimated secondary magnetic flux, which are derived from said measuring unit, to thereby produce said estimated rotation angular velocity,
- c) a secondary-resistance estimating unit for processing said state deviation, said estimated secondary magnetic flux, and said estimated secondary current, which are derived from said measuring unit, to thereby produce said estimated secondary resistance,
- d) a primary-resistance estimating unit for processing said estimated secondary resistance derived from said secondary-resistance estimating unit, to thereby produce said estimated primary resistance,
- e) a gain computing unit for processing said estimated rotation angular velocity derived from said rotational-speed estimating unit, to thereby produce said feedback gain so that said state deviation contains a component orthogonal to said estimated secondary magnetic flux,
- f) when a deviation is produced between said rotation angular velocity and said estimated rotation angular velocity of the induction motor, said gain computing unit produces a feedback gain causing a component orthogonal to said estimated secondary flux contained in said state deviation, and,
- g) said secondary-resistance estimating unit executes a process by use of the product of a component being in phase with an estimated secondary magnetic flux contained said state deviation and another component being in phase with said estimated secondary magnetic flux contained in said estimated secondary current, to thereby produce an estimated secondary resistance.
10 more elements
Dependencies are inferred from the claim text.