Virtual flux-based dual-PWM frequency converter model prediction direct power control method

Abstract

Disclosed is a virtual flux-based dual-PWM frequency converter model prediction direct power control method. The method comprises the steps of collecting three-phase alternating current power grid voltages e<sa>, e<sb> and e<sc>, rectifier grid side three-phase line currents i<sa>, i<sb> and i<sc>, a direct current bus voltage u<dc>, and three-phase stator currents i, i and i<c>; enabling adifference value between the direct current bus voltage u<dc> and a given direct current bus voltage u<dcref> to pass through a PI regulator to obtain a given load current I<dcref>; enabling the givenload current to be multiplied with the direct current bus voltage to obtain given active power p<ref>, wherein the given reactive power q<ref> is equal to 0; obtaining instantaneous active power andinstantaneous reactive power according to the components of the rectifying side three-phase alternating current voltages and three-phase line currents in an alpha-beta coordinate system and by virtueof the virtual flux <Psi><s>, and solving power differential, and obtaining active and reactive prediction values before the next period is started according to a one-order linear equation; and enabling the inversion side to perform conversion of coordinates according to a rotor flux orientation vector control strategy so as to realize full decoupling of the motor torque and flux control. By virtue of the method, the dynamic response speed of the system is improved, the anti-disturbance performance of the system is improved, and the frequency conversion system has higher advantages.

Description

technical field [0001] The invention relates to the field of power electronics and electric transmission, in particular to a direct power control method based on a virtual flux linkage-based dual PWM converter model prediction. Background technique [0002] In recent years, due to the dual-PWM frequency conversion system has improved the defects of traditional inverters using diode uncontrolled rectification and phase-controlled rectification, it has the advantages of energy can flow in both directions, unit power factor operation, network measurement current harmonic content is small, DC side voltage fluctuations Smaller and other advantages become the focus of current research. The dual PWM frequency conversion speed regulation system has a wide range of applications, but the dynamic and static performance requirements of the system are getting higher and higher, so there are higher requirements for the control strategy of the dual PWM frequency conversion speed regulation...

AI Technical Summary

Problems solved by technology

At present, there are mainly vector control strategies and direct torque control strategies. Direct torque control has poor low-speed performance and produces large torque ripples. Vector control adopts continuous double PI control, and the torque and flux linkage changes relatively smoothly.

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