Study On Predictive Control Of A Motor Fed By Two-stage Matrix Converter

The main power supply equipment of the AC speed control system is the power converter,and the traditional power converter has been unable to overcome itself inherent defects.Two-stage Matrix Converter has no energy storage capacitor in DC side, saving costs while reducing the device size. At the same time it has some advantages in performance ,including sinusoidal input and output current, controllable input power factor and bidirectional energy flowing. Thus, TSMC has become a very promising new "green" power converter. A motor fed by TSMC not only makes the system has excellent transmission performance, but also no harmonic pollution to the grid.TSMC structure is an integration topology structure, where exists mutual coupling problems between the rectifier stage and the inverter stage. In the TSMC driven motor system,voltage and current of converter output side related to the transmission performance of motor,and the input current related to power quality of the grid. However, conventional space vector modulation is an approximate open-loop control, which can not eliminate the coupling disturbance between the two stages. In addition, many occasions requirements are getting higher and higher on the performance of motor control, the traditional control methods have been difficult to meet the demand of high control performance.Aiming at the above problems, predictive control is introduced into the integrated control of TSMC driven motor. The TSMC drive motor system mathematical model is established and discretized by using the input voltage, current, input voltage of switching circuit, TSMC switch matrix model, stator current and rotor angular velocity of motor, establishing the cost function which is composed by the absolute error of the predicted flux magnitude, the absolute error of the predicted torque according to the discrete mathematical model. Then, the switching states of the TSMC are optimized with the cost function as the constraint, realizing motor control by the optimal switching state. The proposed method can ensure the good performance of the grid side and overcome the influence of the uncertain factors such as model error and external disturbance.In order to verify the correctness and validity of the proposed scheme, simulation and experiments are carried out, setting up experimental platform with FPGA as the core control and the system hardware and software are designed on the basis of theoretical.. The results show that the predictive control of TSMC driven motor realizes the effect of high precision of the motor stator flux, electromagnetic torque tracking its reference value and the input reactive power minimum is minimized, so that the system has the excellent network side and transmission performance.