| Direct torque control (DTC) is a kind of new high performance AC driving technique followed the vector control technique, the method hasn't complicated vector transform, and it has simple system structure, good static and dynamic performance. Now, most of the power converters of AC motor control system with DTC technique are AC-DC-AC converters, the widely use of this kind of converters will seriously pollute the power network, in the long run, it can be overcome by two-stage matrix converter (TSMC). In order to achieve high performance as well as to meet the electromagnetic interference requirement, it is adopted a novel DTC method for asynchronous motor fed by TSMC in the paper, it is possible for this kind of compound control system to combine the advantages of TSMC with DTC schemes.The principle and the realization of DTC are introduced, based on the detailed analysis of control scheme of TSMC, the modulation method is proposed. But PI controller is often affected by parameter changed, the adaptability of changing load and anti-disturbance are very poor, owing to the disadvantage of PI controller, this paper introduces a new nonlinear controller—active disturbance rejection-controller (ADRC).In this paper the compound control system is simulated by Matlab/Simulink in detail, the simulation models of two speed controller are constituted. The result of simulation indicates that the proposed modulation method is effective and the performance of compound control system with excellent input characteristics are superior to the DTC system in which the AC-DC-AC converter is used. The result of simulation also shows that using ADRC can obtain better dynamic performance, and ADRC has better adaptability and robustness compared with PI controller.Based on the theoretical research, a experimental system of compound control system is designed in the paper, which includes main power board, sampling circuit and controlling circuit, which a chip of TMS320LF2407A is chosen as main chip to construct the hardware system. The DSP based on control algorithm is implemented in the software design. |
