The Improvement And Analysis On Stability Of Matrix Converter System

Currently, the research focused primarily on matrix converter application of a series of problems, such as uneven curb, switches depletion, stability, the matrix will be applied to the vector control and direct torque converter control asynchronous motor adjustment system, and other issues research. To further advance the process of matrix converter practical for matrix converter system stability analysis is particularly important. Currently, the international community, the stability of the matrix converter study has just started, matrix converter stability mechanisms to be in-depth research.Firstly, the stability of an electrical drive fed by a three-phase to three-phase matrix converter is analyzed by a small signal model .A state average model of the whole system,which takes into account the parameters of the power supply and the input L-C filter, is proposed .The stability of the system is evaluated by analyzing the migration of eigenvalues of the system, which is linearized around a steady-state operating point. Based the model two improvement methods are proposed. One of methods is improvement on the structure of input filter; the other is improvement on the control schemes. Usually, the duty-cycles of the switching configurations are calculated on the basis of the instantaneous input voltage values, whereas for improvement on the system stability, they are calculated applying a digital low-pass filter to the input voltage.Secondly, in high-power wind power generation system, voltage source grid-connected inverter is important for power transporting and energy converting. But the output current with harmonic distortion is increased due to lower switching frequencies. An alternative filter is a T-filter, which can achieve reduced levels of harmonic distortion at lower switching frequencies. But it make instability is bring to system by using a T-filter. The strategy integrates a loop bridge current regulator with grid current and voltage feed forward to stabilize the system.Theoretical considerations are supported by simulation results.