Multiple low frequency current ripple suppression method based on active virtual inductor

Abstract

The invention discloses a method for suppressing multiple low-frequency current ripples based on an active virtual inductor. The ripple suppression branch consists of an active virtual inductor L vri with capacitor C real It is connected in series and connected in parallel at the DC bus terminal. Active virtual inductor L vri is composed of a pair of complementary conducting switches S a with S b , an inductor L r and a capacitor C r constitute. The multiple low-frequency ripple suppression method absorbs the low-frequency current ripple at the DC bus end, so that the pulsating energy is transferred between the DC bus and the topology structure, and has little impact on the load. This method can deal with single or multiple low-frequency current harmonics at the same time, and has strong generality. At the same time, the topology has good low-frequency ripple suppression effect and fast response speed during circuit operation. The present invention can achieve better ripple suppression effect by using an inductance with a smaller inductance value and a capacitor with a smaller capacitance value, increasing the power density of the system, improving the power supply efficiency, prolonging the service life of the power supply, and enhancing the circuit stability.

Description

technical field [0001] The invention relates to the technical field of power quality, in particular to a method for suppressing multiple low-frequency current ripples based on an active virtual inductor. Background technique [0002] In the AC-DC microgrid with DC bus, there are various types of AC loads, and the output power often presents multiple low-frequency pulsations, which are fed back to the DC bus side, which will cause the DC bus to generate different times of current or low-frequency voltage. ripple. However, most of the distributed power sources are in the voltage source output mode, that is, the DC bus voltage is generally kept constant. Therefore, the DC bus current must contain a large number of superimposed multiple low-frequency ripples. These low frequency ripples can reduce the output power and conversion efficiency of the inverter and cause damage to the power supply. [0003] At present, the effective low-frequency ripple suppression methods for the D...

AI Technical Summary

Problems solved by technology

The traditional method is to connect a large inductor in series or a large capacitor in parallel on the DC bus. Compared with the active energy storage circuit, the power density is low

At present, the most widely used is to use active energy storage circuits for power balance to suppress low-frequency ripples, but the technology for multiple low-frequency ripples has not yet been reported.

Images