| The PWM rectifier can be applicated to the frequency control system,and it has a high power factor,low current harmonic wave,energy feedback and quickly dynamic response etc.These advantages can make the PWM rectifier as an ideal interface of the electric appliance or electric net with other electric equipment.Topology,the mathematical model,working principle and control strategy of PWM rectifier are analyzed in detail in this paper.The direct power control(DPC) topology structure, principle and the structure of switching table are described and analysed in detail based on three phase mathematical model of rectifiers.In view of the present traditional switch table insuffi-ciency, which conduces to active power and reactive power adjustment weakly.constructing the new switch table is proposed,thus the system output performance is improved.The simulation result verifies the feasibility of the strategy.In order to meet working situation's need,a dual single-input single-output(DSISO)model based on six intervals is proposed, and the three-phase PWM rectifier is equivalent to two single-phase full-bridge PWM rectifiers,which can imple-ment directional power flow. Based on the model and space vector modulation, the control strategy is analyzed to determine switching control signals in a switching period.The resisitor experiment, motor experiment without load, and motor experiment with load are carried out.The experimental results confirm the validity of the DSISO model and its control strategy.According to the DSISO model based on six intervals,the nonlinear characteristics of PWM rectifier are studied in detail with phase-space reconstructing algorithm.Quantitative chaos analysis is implemented by phase graph and power spectrum, and qualitative chaos analysis is implemented by calculating the maximum Lyapunov exponent and correlation dimension.By analysis, calculation and simulation, the chaotic characteristics of PWM rectifier are verified.
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