Papers by Keyword: Direct Torque Control (DTC)

Abstract: This paper proposes a stator flux and rotor speed estimation method for induction motor (IM) based on extended complex Kalman filter (ECKF). A complex-valued model is adopted that allows a simpler and more effective state estimation of IM. And a third order ECKF has been designed for IM model by neglecting the mechanical equation, which is a valid hypothesis when the motor is operated at a constant rotor speed. The stator flux and rotor speed estimation obtained from ECKF are applied for direct torque control (DTC) of induction motor. This method for state estimation is more effective and easier than the one performed on the corresponding real-valued model, as it obtains observability conditions directly in terms of stator current and flux complex-valued vectors. The proposed ECKF achieves a good performance in DTC of IM. Simulation experiment results in Matlab/Simulink environment validate the proposed method.

Abstract: Because of the reliability requirement for the motor driving system in practical application, and based on analysis of the working principle of a fault-tolerant inverter, the direct torque control (DTC) for brushless direct current motor (BLDCM) fed by four-switch three-phases inverter (FSTPI) when the inverter faults is widely studied. According to the characteristics of (BLDCM), the voltage space vector for BLDCM-DTC fed by FSTPI is redefined due to the dissymmetric voltage space vector of TPFSI. To reduce the number of power device switching, the implementation method of four-switch SVPWM with seven-segment scheme was presented. Therefore, the system model is established as a result of the detailed analysis of voltage space vector and the control principle of the BLDCM-DTC without flux linkage observation fed by FSTPI. The validity and effectiveness of the proposed scheme have been verified through the simulation and experimental results.

Abstract: The simulation model of permanent magnet synchronous motor system based on speed sensor-less direct torque control is built by analysing the mathematic model of permanent magnet synchronous motor and the theory of direct torque control in this dissertation, and the system’s speed and position is estimated by calculating the angle of stator flux linkage. MATLAB/Simulink is utilized to simulate the system, and the simulation results are analyzed, with which the simulation result prove the correctness and feasibility of the estimation using in this dissertation and good dynamic response performance of the system.

Abstract: The paper introduces Working mode of brushless doubly-fed machine（BDFM） and mathematical model in the d-q coordinates for BDFM，a strategy of discrete space vector modulation in direct torque control for BDFM has been Proposed 。The paper uses Matlab / Simulink to model and simulate the system of the direct torque control for brush double-fed motor based on discrete Space Vector Modulation.Simulation results prove that the discrete space vector modulation technique can reduce the torque ripple of traditional direct torque control system for BDFM, and improve waveform of current and Flux of Control winding.

Abstract: In this paper, a method of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) based on fuzzy regulator is proposed. It overcomes the disadvantages such as speed drop with load, torque ripple etc., which happens in the DTC for PMSM based on conventional PI regulator. The simulation results show that, the DTC for PMSM based on fuzzy regulator can effectively improve the system loading capability and significantly reduce the torque ripple and the harmonic content of the system. Therefore, it can comprehensively improve the system performance.

Abstract: Direct torque control (DTC) as a new type of motor control strategy, make the control system has good dynamic regulation performance. In this paper, we use the theory of direct torque control to research the speed regulation system of asynchronous motor direct torque control principle and its main component. Use Matlab/Simulink library to build the simulation model of induction motor DTC complete simulation and results show that the direct torque control run time has good control effect in asynchronous motor.

Abstract: Has the advantages of quick response of PMSM using the method of DTC, but will make the high torque and big magnetic flux linkage ripples. In order to solve this problem, using the fuzzy neural network hybrid system to replace the traditional hysteresis controller, Strong learning ability and fuzzy logic in handling uncertain information has the adaptive ability of neural network, the fuzzy neural network hybrid system to produce the expected voltage vector, the speed of a smooth transition of permanent magnet synchronous motor. The proposed method is validated by simulation under external disturbances in motor is very effective to reduce the ripple of torque and flux, the speed of the fast response and smooth transition.

Abstract: Compared with vector control, direct torque control (DTC) spurned coupling idea and canceled circumgyration coordinates transform. By detecting motor’s stator voltage and current, along with calculating motor’s flux and torque in virtue of the instantaneous space vector theory, DTC controlled flux and torque directly according to the difference between the detecting value and design value. DTC also reduced calculation amount and overcomed the flaw that the system was disturbed by motor’s parameters easily, which were the problems in the vector control. On the basis approach mentioned above, this paper realized the system simulation using DTC. Simulation shows that asynchronous motor control has favorable ability of speed adjusting, short startup time, excellent stability.

Abstract: In order to improve the stability of an electric vehicle on different road conditions, this paper puts forward a fuzzy PI direct torque control of an adaptive, through the electronic differential control, the parameters of two high torque motor is adjusted dynamically, so as to replace the traditional mechanical differential. Analysis for system stability, the simulation results show that, with Matlab/Simulink, in a different way, this method can obtain good steady-state tracking accuracy and small dynamic error integral.

Abstract: This paper presents improved Fuzzy Logic Controller (FLC) of the Direct Torque Control (DTC) of Three-Phase Induction Motor (IM) for high performance and torque control industrial drive applications. The performance of the IM using PI Controllers and general fuzzy controllers are meager level under load disturbances and transient conditions. The FLC is extended to have a less computational burden which makes it suitable for real time implementation particularly at constant speed and torque disturbance operating conditions. Hybrid control has advantage of integrating a superiority of two or more control techniques for better control performances. A fuzzy controller offers better speed responses for startup and large speed errors. If the nature of the load torque is varied, the steady state speed error of DTC based IM drive with fuzzy logic controller becomes significant. To improve the performance of the system, a new control method, Hybrid fuzzy PI control is proposed. The effectiveness of proposed method is verified by simulation based on MATLAB. The proposed Hybrid fuzzy controller has adaptive control over load toque variation and can maintain constant speed.