Application and practice of portable bi-directional DC-AC energy storage converter based on second order generalized integrator phase-locked loop and HERIC circuit

Abstract

In various industries, including the production of new energy and electric vehicles, portable bidirectional converters are crucial for enhancing power supply reliability. In recent years, these converters have become increasingly normal in daily life. Bidirectional converters have not been as popular or have not been used as much due to issues with phase tracking on grids connected to leakage current in the converter system. The essential features and principles of the portable bidirectional energy storage converter proposed in this paper, which is based on a second-order generalized integrator phase-locked loop, are theoretically investigated. Formulas are also generated using small signals to address this issue. PLECS simulation software was used for parameter design and algorithm simulation to test the effectiveness of the phase-locked loop under various operating situations. Therefore, a set of appropriate phase-locked structure models for this circuit was developed. An experimental verification platform was constructed to confirm the accuracy of the design parameters: the front stage uses the H-bridge; the backstage, which uses the front stage, adopts the H-bridge; and the rear stage adopts the topology platform of the HERIC topology + LCL filter circuit. The test data indicates that, the addition of the HERIC topology and soft switching resulted in a 94 % reduction in leakage current and a 1.6 % improvement in efficiency. Analysis and comparison results of the test data confirmed the consistency between the experimental effect and the design parameters, achieving the expected effect and proving the accuracy of the topology and mathematical model. The design methodology and design parameters of this thesis are useful and instructive for similar or related research.