Research On Duty-cycle Space-vector Modulation Strategy Of Multiphase Matrix Converter

In recent years,multiphase power converters that power multiphase motors are receiving much attention with an increasing demand for multiphase motor drive systems in many fields.With the continuous development of modern power electronics and automatic theory,multiphase matrix converter(MC)has become one of the most promising members in multiphase power converters and has become a research hotspot in this field due to its advantages,such as,the development direction of modularization,excellent input and output characteristics,controllable input power factor,and so on.Based on three-phase sinusoidal AC power in China,this paper mainly studies the modulation strategy of three-to-P phase MC.Firstly,this paper deeply analyzes and studies the three-to-five phase MC,and proposes a duty-cycle space-vector modulation strategy,and extends it to the MC of arbitrary phase output.Through the research and analysis of the input and output side space vectors based on decoupling transformation,the expressions of 5 duty-cycle space-vectors are obtained;15 duty-cycles are acquired according to the concept of single-phase duty-cycle space-vector;and then,the voltage transfer ratio(VTR)and the number of commutations are analyzed.In addition,this paper deeply studied geometric representation of each duty-cycle space-vector;15 duty-cycles are decomposed,recombined,and represented by 8 recomposition duty-cycles.The space-vector modulation strategy based on recomposed duty-cycles can be obtained,which simplifies the process of solving the duty-cycles in traditional one.Finally,this paper proposes the generalized double line voltage synthesis strategy,which is no segment partitions and combinations and can be easily extended to any number of output phases and greatly reduces the complexity of programming.By using a novel switching sequence arrangement,the relationship among duty-cycles is fixed to one state.This strategy is analyzed in detail taking an example of three-to-five phase MC,and extends it to a multi-phase matrix converter.In addition,this paper proposes that the double line voltage synthesis strategy based on recomposed duty-cycles.The simulation model of three-to-five phase MC is established by MATLAB/Simulink.And the simulation results prove the feasibility of the theoretical method with different S-function.