Authors: Khadim Moin Siddiqui, Kuldeep Sahay and V.K. Giri
In industries, the three phase squirrel cage induction motor is widely used due to its simple construction, robust design and low operational costs. The exploitation of squirrel cage induction motor with power semiconductor devices based inverters presents the greater advantages on cost and energy efficiency, compared with other industrial solutions for varying speed applications. Since, Inverter fed-induction motors are gathering great attractiveness for multi-megawatt industrial drive applications these days. In the present paper, an extensive simulation has been carried out for open and closed loop models of 3HP, 50 Hz, 1430 RPM switching function based voltage source inverter fed into induction motor. The transient analysis has been carried out by both models. The analysis has been carried out in the recent MATLAB/Simluink environment. The open and closed loop models give encouraging results and observed that the closed loop model gives better results as compared to open loop model with reduced harmonics. Six motor signatures are used for analysis purpose; these are stator current, rotor current, rotor speed, electromagnetic torque, q-axis rotor flux and q- axis stator flux respectively. Though, it has been seen that the stator current parameter has been widely used parameter in last two decades with Motor Current Signature Analysis (MCSA). Therefore, in the harmonic analysis only stator current parameter is used. The torque control method is used for controlling the induction motor in closed loop due to its advantages over vector or field-control method.
Squirrel Cage Induction Motor (SCIM), Voltage Source Inverter (VSI), Pulse Width Modulation (PWM), Direct Torque Control, Open/Closed Loop, MATLAB/Simulink.
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