VIENNA rectifier neutral point potential alternating-direct-current component balance control method

Abstract

The invention discloses a VIENNA rectifier neutral point potential alternating-direct-current component balance control method which can reduce design capacity of a capacitor on a direct-current side and a filter on an alternating-current side and save cost of a tri-level VIENNA rectifier. On the basis of common mode component injection modulation, a common mode component direct-current compensation coefficient and an alternating-current compensation coefficient are modified dynamically, so that the problem of neutral point unbalance of direct-current and alternating-current components is solved; more importantly, the method guarantees uniformity between triphase alternating-current side harmonic distortion rate and SVPWM while substantially inhibiting neutral point potential low-frequency oscillation in conventional modulation methods and improving quality of output power and can be popularized and applied in the field of battery testing, charging facilities and driving systems.

Description

technical field [0001] The invention relates to the field of power electronics with high power factor and high power density, in particular to a method for controlling the balance of AC and DC components of a VIENNA rectifier midpoint potential. Background technique [0002] Active power factor correction technology is an effective way to solve the problem of nonlinear components injecting a large number of harmonics into the grid. Three-phase three-level VIENNA rectification can realize input unit power factor correction, not only has the advantages of small harmonics, low switching loss and small electromagnetic interference, but also has a simple circuit structure, a small number of switches, and no bridge arm through problems. It is suitable for high-voltage and high-power conversion occasions, but the inherent midpoint balance problem of VIENNA rectifier circuit topology restricts its popularization and application. [0003] The midpoint potential imbalance of VIENNA r...

AI Technical Summary

Problems solved by technology

However, due to the complex factors that cause the unbalance of the AC and DC components of the midpoint potential, it is extremely difficult to control. The traditional SPWM modulation method has a small adjustable output range and large harmonics, so that the AC component unbalance control problem that causes the midpoint potential oscillation has not been solved.

[0004] Midpoint potential oscillation will increase the stress on the DC side capacitor and semiconductor devices, resulting in overdesign of the DC side capacitor, increasing the cost of the converter, and reducing its operational reliability

Especially in the case of high power and high modulation ratio, midpoint potential oscillation introduces low-frequency harmonics on the DC side, resulting in poor power quality

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