Introduction:
There are many senseless methods. Which, class to two main kinds, openloop and close-loop. Up to this moment, there are many open-loop sensorless schemes have been presented but all of them have many defected by motor parameters and feed-back variable like stator current and voltage . Which, give many defected to control scheme, therefore they also make defect to operation process of induction motor. This kind of defected belong scheme by scheme of open-loop method. Shortly, this method has many defected by motor parameter and feed-back signals, stator resistance is the most importance defecting parameter. Special in low speed performance of motor and if rotor flux has been estimated by stator flux, it also get the defected by stator resistance. Opposite, close-loop method gives a better solution. It gets very low defected by motor parameter and feed-back variable because calculate and estimate process always have feed-back to adjust transition error. This method manage to estimate rotor speed by two models so call reference model and adaptive model, which work parallel to estimate rotor flux and the error of 2 those signals have been adjusted to zero through PI control unit to get the actual speed of rotor.
The operation of speed controlled ac drives without mechanical speed or position sensors equires the estimation of internal state variables of the machine. The assessment is based exclusively on the stability and capability to compensate machine parameters during operation of motor. This project gives one of the best method to design the drive without speed sensor, MRAS, which estimates speed and compensate machine parameters. Depending on requisition or working condition of the drives, each machine parameter has been monitored and compensated case by case. Stator resistance, Rs, has been compensated in this paper. Beside that, MRAS helps sensorless system work well incase the feedback variables have transition error.
There are many senseless methods. Which, class to two main kinds, openloop and close-loop. Up to this moment, there are many open-loop sensorless schemes have been presented but all of them have many defected by motor parameters and feed-back variable like stator current and voltage . Which, give many defected to control scheme, therefore they also make defect to operation process of induction motor. This kind of defected belong scheme by scheme of open-loop method. Shortly, this method has many defected by motor parameter and feed-back signals, stator resistance is the most importance defecting parameter. Special in low speed performance of motor and if rotor flux has been estimated by stator flux, it also get the defected by stator resistance. Opposite, close-loop method gives a better solution. It gets very low defected by motor parameter and feed-back variable because calculate and estimate process always have feed-back to adjust transition error. This method manage to estimate rotor speed by two models so call reference model and adaptive model, which work parallel to estimate rotor flux and the error of 2 those signals have been adjusted to zero through PI control unit to get the actual speed of rotor.
The operation of speed controlled ac drives without mechanical speed or position sensors equires the estimation of internal state variables of the machine. The assessment is based exclusively on the stability and capability to compensate machine parameters during operation of motor. This project gives one of the best method to design the drive without speed sensor, MRAS, which estimates speed and compensate machine parameters. Depending on requisition or working condition of the drives, each machine parameter has been monitored and compensated case by case. Stator resistance, Rs, has been compensated in this paper. Beside that, MRAS helps sensorless system work well incase the feedback variables have transition error.
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