Optimal modulation method and optimal modulation system for non-isolated alternating-current bypass single-phase grid-connected inverter

A technology of AC bypass and inverter, applied in AC network circuit, AC power input conversion to DC power output, single network parallel feeding arrangement, etc., can solve problems such as zero-crossing distortion, reverse charging, etc.

Active Publication Date: 2016-09-28
CENT SOUTH UNIV
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Problems solved by technology

[0005] Aiming at the defects in the prior art, the present invention provides an optimized modulation method and system for a non-isolated AC bypass type single-phase grid-connected inverter, which can solve the problem of zero-crossing distortion caused by ignoring the inductor voltage in the existing modulation method and Reverse charging problem due to insertion dead zone

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  • Optimal modulation method and optimal modulation system for non-isolated alternating-current bypass single-phase grid-connected inverter
  • Optimal modulation method and optimal modulation system for non-isolated alternating-current bypass single-phase grid-connected inverter
  • Optimal modulation method and optimal modulation system for non-isolated alternating-current bypass single-phase grid-connected inverter

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Embodiment Construction

[0071] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0072] figure 1 A flow chart showing an optimal modulation method for a non-isolated AC bypass type single-phase grid-connected inverter provided in Embodiment 1 of the present invention, see figure 1 , the optimized modulation method of the non-isolated AC bypass type single-phase grid-connected inverter, comprising the following steps:

[0073...

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Abstract

The invention provides an optimal modulation method and an optimal modulation system for a non-isolated alternating-current bypass single-phase grid-connected inverter. The method comprises the following steps: acquiring the phase angle Omega(t) of the voltage of a power grid; acquiring the phase angle Omega(t)+Beta of the output voltage of an inverter; and judging an interval, needing insertion of a dead zone, of the output voltage of the inverter according to the power factor angle Alpha and the phase angle difference Beta between the output voltage of the inverter relative and the voltage of the power grid, and inserting a dead zone between a bypass freewheeling switch and a main switch in an interval in which the output power of the inverter is negative. By using the optimal modulation method for a non-isolated alternating-current bypass single-phase grid-connected inverter provided by the invention, the problem of zero-crossing distortion caused by ignorance of inductance voltage and the problem of reverse charging caused by insertion of a dead zone for the existing modulation method are solved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an optimized modulation method and system for a non-isolated AC bypass type single-phase grid-connected inverter. Background technique [0002] Solar power generation is one of the important means of efficient energy utilization. In order to realize the grid-connected operation of the photovoltaic system, it is necessary to perform power conversion through power electronic devices. Among them, the inverter plays a vital role as the interface between the photovoltaic system and the grid. Non-isolated photovoltaic grid-connected inverters have the advantages of high efficiency, small size, light weight and low cost. However, due to the existence of the parasitic capacitance of the solar panel to the ground, the switching action of the switching device of the grid-connected inverter may generate a high-frequency time-varying voltage to act on the parasitic capacitance, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02M7/537H02M1/32
CPCH02J3/383H02M1/32H02M7/537Y02E10/56
Inventor 孙尧邓书豪朱奇杨建粟梅
Owner CENT SOUTH UNIV
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