Multi-rotation coordinate phase-locked loop and control method for electric vehicle charger

Abstract

The invention relates to a multi-rotating coordinate phase-locked loop for an electric vehicle charger and a control method. A novel filter structure is adopted, the filter structure can quickly filter an arbitrary-order harmonic component in power grid voltage, and influences on the output angular frequency and the phase information of the digital phase-locked loop by a non positive sequence fundamental component of the power grid voltage can be effectively avoided; in aspects of calculating the angular frequency and the phase information of the power grid voltage, a brand-new design is adopted, the angular frequency and the phase information of the power grid voltage can be outputted almost in a no-delay mode, and thus, the phase-locked speed and the phase-locked precision of the overall digital phase-locked loop can be greatly improved. The multi-rotating coordinate phase-locked loop for the electric vehicle charger and the control method of the invention can be applied to an electric vehicle DC charger in a power grid voltage environment and can be applied to the field of power electronics involving PFC control, and have the advantages of quick phase-lock speed and high precision.

Description

technical field [0001] This patent belongs to a multi-rotation coordinate phase-locked loop and a control method applied to electric vehicle chargers. The electric vehicle DC charger using the new digital phase-locked loop technology has lower grid-side current harmonic content THD, higher grid-side power factor, faster dynamic response of the system, and can adapt to DC electric vehicle charger A variety of complex grid environments. Background technique [0002] With the continuous reduction of non-renewable energy sources, promoting the rapid development of new energy sources has become a top priority. In the automotive industry, electric vehicles have emerged as the times require. As a green vehicle with broad development prospects, their popularity will be extremely rapid in the future. The future market prospect is also extremely huge. As an important supporting facility for electric vehicles, DC chargers for electric vehicles are increasingly valued by society and t...

AI Technical Summary

Problems solved by technology

[0005] At present, the PFC part of the electric vehicle DC charger on the market often adopts the most common three-phase software phase-locked loop (SRF-PLL) based on a single synchronous rotating coordinate system (SRF-PLL) or the most basic zero-crossing phase-locked loop Three-phase grid voltage phase and frequency capture, these phase-locked loops are difficult to suppress the influence of DC bias, harmonics and other interference in the grid voltage signal, resulting in low output phase and frequency accuracy, resulting in large grid-side current harmonic THD , low power factor, and low efficiency will ultimately affect the actual performance of the PFC part of the DC electric vehicle charger

More importantly, commonly used software phase-locked loops such as the three-phase software phase-locked loop (SRF-PLL) based on a single synchronous rotating coordinate system or the most basic zero-crossing phase-locked , it is impossible to ensure effective suppression of grid harmonics, DC bias and negative-sequence fundamental components while maintaining a fast dynamic response speed, which makes the grid-side current of the entire electric vehicle DC charger unable to be fast when the grid voltage is polluted. It also outputs the phase of the positive-sequence fundamental wave component of the three-phase grid voltage with high precision, thereby reducing the quality of the grid-side current and greatly increasing the harmonic content THD of the grid-side current, which affects the normal operation and use of the DC charger for electric vehicles scope

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