Three-level Boost converter neutral-point potential balance control method

Abstract

Disclosed is a three-level Boost converter neutral-point potential balance control method. The method is characterized by comprising the steps that 1, a voltage sensor VTincap1 is arranged on a three-level Boost converter output filter capacitor Cb1, detection data is capacitor voltage ucb1, a voltage sensor VTincap2 is arranged on the output filter capacitor Cb2, and the detection data is capacitor voltage ucb2; 2, a controller is connected to a three-level Boost converter, and the controller comprises an AD conditioning circuit, a DSP, an FPGA and a driving circuit; the two input ends of thecontroller are connected with the voltage sensor VTincap1 and the voltage sensor VTincap2 respectively, the sampling signal capacitor voltage ucb1 and the capacitor voltage ucb2 enter the controller,and output signals of the controller are drive pulse connected to two switching tubes Qb1 and Qb2; a deviation voltage gain feature coefficient sectional analytical expression is given, and the sectional fitting method based on maximum deviation voltage conditions is put forwards, so that different duty ratio section phase delay boundary conditions are determined, and therefore the deviation voltage is better and effectively regulated.

Description

technical field [0001] The invention relates to a midpoint potential balance control method of a three-level Boost converter, relates to the field of multilevel conversion, and in particular to a midpoint potential balance control method of a three-level Boost converter. Background technique [0002] The three-level Boost converter evolved from the flying-capacitor-clamped multilevel inverter proposed by Meynard T.A. and Foch H. in 1992, which can effectively reduce the voltage stress of the switching tube, reduce switching loss and reverse recovery It helps to improve the dynamic performance of the system, reduce harmonic distortion and reduce the volume and weight of inductors and capacitors to increase the power density of the system. It has broad application prospects in medium and high-power switching power supplies. However, in practical applications, there are certain differences in the two output filter capacitors, equivalent series resistances, and output loads of t...

AI Technical Summary

Problems solved by technology

Among them, although the duty ratio independent control method can adjust the deviation voltage, the introduction of the deviation voltage control value changes the output characteristics of the three-level Boost converter, and there is a complex coupling relationship, which is not conducive to the controller design; and the pulse The phase delay control method can effectively adjust the deviation voltage without changing the output characteristics of the system. However, in the previous methods, an accurate mathematical model of the system was not established, and there was a lack of guidance for the design of key control parameters, which resulted in the control accuracy and dynamic response. not high speed

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