Analysis And Optimization Of Variable-Frequency Soft-Switching Peak Current Mode Control Techniques For Microinverters

Keywords

Boundary conduction mode (BCM); microinverters; power loss analysis; soft switching; three-phase inverters; zero current switching (ZCS); zero voltage switching (ZVS)

Abstract

This paper presents a detailed power loss model for a microinverter with three different zero voltage switching boundary conduction mode (BCM) current modulation methods. The model is used to calculate the optimum peak current boundaries for each modulation method. Based on the power loss model, a dual-zone modulation method is proposed to further improve the microinverter efficiency. The proposed modulation method provides two main benefits: the addition of one more soft switching transition and low inductor peak current. The additional soft switching transition reduces switching losses by means of zero current switching. The lower peak current boundary reduces inductor rms current and conduction losses as well as allowing the output filter inductor to be smaller and more efficient. An improved BCM peak current control method was proposed and implemented on a microinverter prototype. The control circuit provides a highly accurate representation of the filter inductor current waveform and also provides galvanic isolation that simplifies control circuit design. The experimental results on a 400-W three-phase half-bridge microinverter validate the theoretical analysis of the power loss distribution and demonstrate that further improvement in efficiency can be achieved by using the proposed dual-zone modulation method.

Publication Date

2-1-2018

Publication Title

IEEE Transactions on Power Electronics

Volume

33

Issue

2

Number of Pages

1644-1653

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/TPEL.2017.2676097

Socpus ID

85034236159 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85034236159

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