Capacitor voltage balance control method of three-phase T-type three-level dual-output inverter

Abstract

The invention relates to a capacitor voltage balance control method of a three-phase T-type three-level dual-output inverter, which is characterized in that on the basis of a carrier PWM (Pulse Width Modulation) method of the three-phase T-type three-level dual-output inverter, the influence of midpoint current on capacitor voltage is analyzed; the invention provides a method for deriving a neutral-point average value current mathematical expression in different intervals according to two groups of modulation wavelength division conditions, and further deriving a condition for realizing capacitor voltage balance. The modulation degrees of the upper and lower groups of modulation waves are reasonably configured, so that the integral value of the midpoint average current in one period is zero, capacitor voltage balance is realized, the harmonic content of the output voltage and current of the three-phase T-type three-level dual-output inverter is reduced, the waveform quality is improved, and the simulation result shows the effectiveness of the control method.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a capacitor voltage balance control method for a three-phase T-type three-level dual-output inverter. Background technique [0002] In recent years, T-type three-level inverters have received widespread attention due to their superior performance, such as low conduction loss and uniform heat distribution. Compared with two-level inverters, three-level inverters have many advantages, such as lower harmonic distortion rate and higher efficiency. The dual AC output system has been widely used in fields such as electric vehicles, rail traction, and wind power generation. The core of the dual AC output system is the dual output inverter. The three-phase T-type three-level dual-output inverter combines the advantages of three-level high-efficiency and dual-output applications, and has great development potential and a wide range of applications. However, in the working process, there ...

AI Technical Summary

Problems solved by technology

The three-phase T-type three-level dual-output inverter combines the advantages of three-level high-efficiency and dual-output applications, and has great development potential and a wide range of applications. However, in the working process, there are two DC The unbalanced voltage of side capacitors leads to unbalanced voltage of power switching devices, large output voltage and current harmonic content, and shortens the life of capacitors.

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