Post Fault Vector Control of CHB Driven Induction Motor

Fathi, Manochehr | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49342 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Zolghadri, Mohammad Reza
  7. Abstract:
  8. Multilevel converters are considered recently as one of the industrial solutions for high-power and power quality demanding applications. Casacade H-Bridge (CHB) converter is one of the well known topologies among multilevel converters. CHB converter is characterized by its high modularity allowing its power to be easily increased. Modularity also allows any faulty cell to be isolated, so the load can be fed by the remaining operative cells, which leads to an unbalanced output voltage of the CHB converter. To avoid the unbalanced operation, recently a solution based on modifying the phase and the magnitude of the voltage refereces has been proposed. This thesis presents a method to control the CHB fed induction motor when a fault occurs in the converter, using FOC method to control the motor. In the proposed method, the unbalaced line voltages of the converter after fault have been balanced in the first place. Then, some changes have been made in the flux and speed controllers of the FOC control system to achieve the optimal opereation point with a reasonable transient. The modified FOC control system has been verified with simulations for different faults. In the steady state post-fault, the FOC control system already tracks the speed refrence effectively using the proposed method
  9. Keywords:
  10. Vector Control ; Fault Tolerance ; Cascaded H Bridge Multilevel Inverter ; Fault-tolerant Control ; Induction Motors ; Post Fault Operation

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