An approach to induction motor drive with controlled voltage source.

DSP‐based vector‐controlled IM drive system with identification of secondary time constant

“…Voltage Model 2.1 Conditions for vector control [2,8) In the development of the following discussion, we shall explain briefly the vector control conditions based on the voltage model of the induction motor. The voltage equation of a 2-pole squirrel cage induction motor in the d-q coordinates rotating synchronously with the rotating field produced by the power source can be expressed as follows, using secondary flux $2: (3) Now, let us consider the d-axi s as the exciting and the q -ax is as the torque component, a s a conventional dc machine; a nd the secondary flux and the seconda r y current a r e orthogonal to each other; that is , (4) Substituting the secondary fl ux in Eq.…”

“…(1), the a ngul a r frequency of the power s ource W o is given by (5) In this case , the block diagram of the induction motor is represented by Fig. (1) and (2) . Howev e r, if <P2 i n Eq.…”

“…As to their control methods, the current source method based on current model of the induction motor [1) as well as the current control method using a voltage source as represented by PWM inverter [2,3) have been proposed; comparisons between these methods have also been made [4). As to their control methods, the current source method based on current model of the induction motor [1) as well as the current control method using a voltage source as represented by PWM inverter [2,3) have been proposed; comparisons between these methods have also been made [4).…”

“…With the progress of adjustable-speed drive of ac motors, vector-controlled induction motors with high-torque response equivalent to dc motors have been implemented in practice. As to their control methods, the current source method based on current model of the induction motor [1) as well as the current control method using a voltage source as represented by PWM inverter [2,3) have been proposed; comparisons between these methods have also been made [4). Then in the vector control of the slip-frequency control scheme, the fact that the temperature drift of the secondary time constant contained in slip-frequency operation will dominate the torque control performance, has long been recognized as a problem [5).…”