Time Delay Compensation for Output Voltage Vector Selection in Direct Torque Control of Induction Machine

The squirrel cage induction motor direct torque control main problems due to torque and large stator flux pulsation. In this an improved model predictive direct torque control algorithm considering multi-step delay compensation is proposed. At each sampling moment, predict the stator flux linkage and torque at the next moment under each voltage vector. The optimal voltage vector deviation from the stator flux linkage reference value and torque reference value are selected as the minimum objective function. Aiming at the problem of one-shot delay in digital control systems, a multi-step predictive delay compensation measure is studied. Simulation shows that the algorithm can effectively reduce torque and stator flux pulsation, reduce current harmonic distortion, and solve the delay problem in digital systems.

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Modified Look-Up Table for Enhancement of Torque Response in Direct Torque Controlled Induction Machine

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v8.i2.pp522-533 ◽

2017 ◽

Vol 8 (2) ◽

pp. 522

Author(s):

Goh Wee Yen ◽

Nik Rumzi Nik Idris ◽

Auzani Jidin ◽

Tole Sutikno

Keyword(s):

Direct Torque Control ◽

Induction Machine ◽

Drive System ◽

Torque Control ◽

Duty Ratio ◽

Activation Time ◽

Light Load ◽

Look Up Table ◽

Voltage Vector ◽

Torque Response

Basically, the direct torque control (DTC) drive system is operated at light load. At light load, supplying the drive system with rated flux will decrease the efficiency of the system. To maximize the efficiency of drive system, an optimal flux has been applied during steady-state but when a torque is suddenly needed, for example during acceleration, the dynamic of the torque response would be degraded. Therefore, a modification to the voltage vector as well as look-up table has been proposed for the torque response improvement. The proposed voltage vector is generated by adding two adjacent conventional voltage vectors and implemented by using duty ratio. The duty ratio is used to estimate the activation time of each conventional voltage vector in order to produce the proposed voltage vector.

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Novel DTC induction machine drive improvement using controlled rectifier for DC voltage tuning

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v10.i3.pp1223-1228 ◽

2019 ◽

Vol 10 (3) ◽

pp. 1223

Author(s):

Nour Mohamed ◽

Tedjini Hamza ◽

Gasbaoui Brahim

Keyword(s):

Direct Torque Control ◽

Induction Machine ◽

Torque Control ◽

Voltage Source ◽

Voltage Vector ◽

Torque Control Strategy ◽

Torque Response ◽

Induction Machine Drives ◽

The Difference ◽

Machine Drives

<span lang="EN-US">The application of the direct torque control strategy for induction machine drives is mainly characterized by torque and flux distortions caused by voltage vector limitation. The goal of this paper is to perform the conventional DTC induction machine drives and reduce ripples of both flux and torque response. The proposed contribution is based on the control of the DC output side of the rectifier feeding the voltage source inverter by means of PI controller in order to adapt the voltage vector used in typical DTC switching table. Mathematic models are built using MATLAB Simulink and programming environment; the simulation results show the difference between the proposed method and classical DTC.</span>

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