Method for monitoring ESR of direct-current bus capacitor of two-stage single-phase inverter

Abstract

The invention discloses a method for monitoring the ESR of the direct-current bus capacitor of a two-stage single-phase inverter. The method comprises the steps that: 1, high-pass filtering is carriedout on direct-current bus voltage vbus to obtain a direct-current bus voltage alternating-current component vbus_ac; 2, performing synchronous sampling on the direct-current bus voltage alternating-current component vbus_ac and an inverter inductive current iL2; 3, denoising the sampled DC bus voltage AC component vbus_ac and the inverter inductive current iL2; 4, obtaining a peak value iL2_peakof the denoised inverter inductive current iL2 and a voltage break variable delta vbus_ac of the direct current bus voltage alternating current component vbus_ac at the corresponding moment; and 5, calculating the value of the ESR of the direct current bus capacitor according to the obtained peak value iL_2peak and the voltage break variable delta vbus_ac. The method provided by the invention doesnot need to add extra sampling points, does not affect the normal work of the converter, is simple and easy to implement, and provides a basis for the health monitoring of the capacitor.

Description

technical field [0001] The invention belongs to the technical field of inverters, and relates to a two-stage single-phase inverter DC bus capacitor health monitoring method, in particular to a two-stage single-phase inverter DC bus capacitor ESR monitoring method. Background technique [0002] At present, distributed power generation systems such as new energy, aircraft and electric vehicles are usually compatible with traditional low-voltage DC power supply system specifications, such as 28V, 42V and other DC power supplies. In order to obtain the 115V or 220V AC required by the load, it is usually necessary to adopt a two-stage structure - the front-stage DC-DC converter completes the inverter input and output voltage matching and electrical isolation, and the rear-stage inverter completes the DC-to-AC conversion and supplies the terminal power supply to the load. [0003] In the two-stage single-phase inverter, since the instantaneous output power of the latter stage inv...

AI Technical Summary

Problems solved by technology

However, there is still a lack of effective health monitoring methods for electrolytic capacitors on the DC bus side

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