A common-mode voltage suppression method for voltage source inverter

Abstract

The invention discloses a common-mode voltage suppression method of a voltage source inverter, which belongs to the technical field of power electronics. In each control cycle of the present invention, an alternative voltage vector is selected according to the voltage vector used in the previous cycle and the sector where the current vector is located in this cycle, and then the objective function is optimized according to the alternative voltage vector, so as to obtain the optimal voltage for this cycle vector and apply it to the inverter. Since the present invention fully considers the influence of the dead zone on the common mode voltage when selecting the alternative voltage vector, the influence of the dead zone can be completely overcome. Therefore, the present invention can be applied to photovoltaic grid-connected inverters or motor drive controllers to reduce the influence of common-mode voltages.

Description

technical field The present invention relates to the application of model predictive control in the field of voltage source inverter control, such as the application of model predictive control in photovoltaic grid-connected inverters and motor drive control, and specifically relates to a voltage source inverter common-mode voltage suppression method . Background technique In the photovoltaic grid-connected inverter system, a large common-mode voltage will generate leakage current to the ground, which will affect the working efficiency of the photovoltaic grid-connected inverter, and even cause harm to personal safety in severe cases. In the field of motor drive control, a large common-mode voltage will generate shaft voltage and shaft current to the motor, which will damage the motor bearing and reduce the service life of the motor. How to achieve common-mode voltage suppression is a research hotspot and difficulty in the field of photovoltaic grid-connected power generati...

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Problems solved by technology

Although the literature "Yan Xueli, Hao Benang, Xia Zitian, et al. Analysis of common-mode voltage suppression strategy based on predictive control [J]. Coal Mine Electromechanical, 2014, (5): 58-64." and the literature "Sung-ki Mun, Sangshin Kwak. Reducing Common-Mode Voltage of Three-Phase VSIs using the Predictive Current Control Method based on ReferenceVoltage[J].Journal of Power Electronics,2015,15(3):712-720.Sung-ki Mun,Sangshin Kwak. Voltage predictive current control method to reduce common-mode voltage of three-phase voltage source inverter [J]. Power Electronics Journal, 2015, 15(3): 712-720.", Chinese Patent "A Permanent Magnet Synchronous Motor Model-predicted common-mode voltage suppression method (201510724306.6)" studies the model-predicted common-mode voltage suppression method of voltage source inverter based on model predictive control, but these methods do not consider the influence of dead zone on common-mode voltage, which leads to common-mode The voltage still has a large voltage spike

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