Induction motor vector control
First Claim
1. A method for vector control of an adjustable-speed induction motor having a secondary resistance, a secondary inductance, and a secondary time constant generally equal to the secondary resistance divided by the secondary inductance, and including means for applying a primary current and voltage to drive the induction motor, comprising the steps of:
- setting a desired motor torque;
setting a desired motor flux;
calculating a slip frequency based on the desired motor torque, the desired motor flux, and the secondary time constant;
sensing the primary current and voltage;
estimating a value for induction motor angular velocity as a function of the sensed primary current and voltage;
summing the calculated slip frequency to the estimated angular velocity to calculate an angular frequency; and
controlling the motor driving means based on the desired motor torque, the desired motor flux, and the calculated angular frequency to vary the primary current and voltage so as to drive the induction motor with no β
-axis secondary flux.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus for vector control of an induction motor. A slip frequency is calculated based on a desired motor torque, a desired motor flux and a motor secondary time constant. An actual value for induction motor angular velocity is estimated as a function of primary current and voltage applied to drive the induction motor. The calculated slip frequency is added to the estimated angular velocity to calculate an angular frequency. The calculated angular frequency is used along with the desired motor torque and the desired motor flux to vary the primary current and voltage so as to drive the induction motor with no β-axis secondary flux.
50 Citations
12 Claims
-
1. A method for vector control of an adjustable-speed induction motor having a secondary resistance, a secondary inductance, and a secondary time constant generally equal to the secondary resistance divided by the secondary inductance, and including means for applying a primary current and voltage to drive the induction motor, comprising the steps of:
-
setting a desired motor torque; setting a desired motor flux; calculating a slip frequency based on the desired motor torque, the desired motor flux, and the secondary time constant; sensing the primary current and voltage; estimating a value for induction motor angular velocity as a function of the sensed primary current and voltage; summing the calculated slip frequency to the estimated angular velocity to calculate an angular frequency; and controlling the motor driving means based on the desired motor torque, the desired motor flux, and the calculated angular frequency to vary the primary current and voltage so as to drive the induction motor with no β
-axis secondary flux. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. An apparatus for vector control of an adjustable-speed induction motor having a secondary resistance, a secondary inductance, and a secondary time constant generally equal to the secondary resistance divided by the secondary inductance, and including means for applying a primary current and voltage to drive the induction motor, comprising:
-
a first source for producing a torque command signal indicative of a desired motor torque; a second source for producing a flux command signal indicative of a desired motor flux; means for calculating a slip frequency based on the torque command signal, the flux command signal, and the secondary time constant to produce a slip frequency signal indicative of the calculated slip frequency; sensor means for sensing the primary current and voltage; means coupled to the sensor means for estimating a value for induction motor angular velocity as a function of the sensed primary current and voltage to produce an estimated speed signal indicative of the estimated motor angular velocity; means for summing the slip frequency signal to the estimated speed signal to provide an angular frequency signal; and a control circuit responsive to the torque command signal, the flux command signal, and the angular frequency signal for controlling the motor driving means to vary the primary current and voltage so as to drive the induction motor with no β
-axis secondary flux. - View Dependent Claims (8, 9, 10, 11, 12)
-
Specification