This paper describes improved torque control of an induction motor. The control is based on direct field orientation with a rotor flux simulator, and motor parameters in the simulator are estimated by a robust identifier with no sensitivity to the stator resistance. Owing to model mismatch in the controller caused by the equivalent core loss resistance, however, both the field orientation and the parameter identification cannot be carried out perfectly, which results in degradation of torque control performance.In order to improve accuracy of the output torque, the proposed system employs a modified machine model taking the core loss into consideration. Consequently, it has been verified through computer simulations that the technique achieves high precision in torque control within a few percent errors.

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Abstract-this paper presents a small electrical power generation for low speed system. The power conversion (roof ventilator) of covert dc voltage to three-phase ac voltage system. The paper proposed two part system, the first part stage about power generate electricity with dc machines, the load will use the energy from the batteries (12V/5Ah) that charged using by roof ventilator. The second part, design 7-level cascade multi-level inverter (INV) topology by using separated dc sources form roof ventilation and batteries. The prototype two part system is built and tested in laboratory. The multi-level INV data collected by MATLAB simulation are used in comparison with the experimental results. This provides guideline to further analyse and improve power conversion in electrical system pertinent to wind turbine roof ventilator generator.

This paper presents an application of an asynchronous back to back VSC-HVDC system, which uses multilevel converter, which uses two-level series voltage connection SPWM converter topology technique. The control strategy is design and implementation of Multi-Terminal on a VSC-HVDC network, representing the future transnational network in Thailand with rated 300MVA (±300kV). The capability to dispatch the offshore wind power as well as the traded power among the onshore grids is explored under wind speed changes. The controller of an asynchronous back to back VSC-HVDC system, the process PQ controller can realize the designated control of active power (P) and reactive power (Q) strategy. The PQ power can exchange controlled independently, the experimental in laboratory tests, and simulation results got from MATLAB/Simulink program software, The Simulation results, the PQ-controller results consist of PMSG rotational speed, voltages and currents, the active and reactive power, DC-bus (kVDC), DC-power (Pdc) and step response command active power, the control of DC-bus voltage is assured by regulation of the active and reactive power. The control strategy of PQ-control to the two-level SPWM converters topology technique for the realization of HVDC system, and to confirm the control strategy provides satisfactory response and strong stability. The system of wind power application is used as a guideline for analyzing and design of the data process control with the PQ-control HVDC system.