High-efficiency module combined type photovoltaic inverter

Abstract

The invention discloses a high-efficiency module combined type photovoltaic inverter which comprises three parts, namely n DC / DC conversion circuits, n power sub-modules and a DC / AC conversion circuit. The inputs of the n DC / DC conversion circuits are connected with n photovoltaic modules, and the outputs of the n DC / DC conversion circuits are connected with n PSMs; the n PSMs are connected in series and then are connected with the input electrode of the DC / AC conversion circuit; and the output of the DC / AC conversion circuit is an alternating-current power grid or a load. According to the invention, the modules are combined and superposed to form multiple levels to realize high-voltage output; each photovoltaic module has independent MPPT control, so that the defect that the output powerof string-type and array-type inverters is reduced due to characteristic differentiation and local shadows of the photovoltaic modules is overcome, and the power generation efficiency of the system ishigher; the cost is low; only one DC / AC circuit is used at the output end, and power flow can be inverted in a centralized mode through power frequency overturning conversion; and multiple assembliesshare the inverter circuit, and thus the cost of the grid-connected link is saved.

Description

technical field [0001] The invention relates to the photovoltaic field, in particular to a high-efficiency module-combined photovoltaic inverter. Background technique [0002] As the cleanest energy source, solar energy has been widely used in recent years. The most common way of photoelectric conversion is photovoltaic power generation, and the open circuit voltage of a single photovoltaic module is a low voltage of about 30V-50V. Many topological structures have been proposed to achieve low voltage and network requirements. [0003] The patent with the notification number CN202406054U discloses a photovoltaic inverter main topology circuit, which applies the traditional three-phase full-bridge inverter to the photovoltaic grid-connected system. Although the circuit has obvious advantages in structure, it has In order to cooperate with this structure, a large number of photovoltaic modules need to be boosted in series, and the higher DC bus voltage is gathered as the input...

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Problems solved by technology

[0003] The patent with the notification number CN202406054U discloses a photovoltaic inverter main topology circuit, which applies the traditional three-phase full-bridge inverter to the photovoltaic grid-connected system. Although the circuit has obvious advantages in structure, it has In order to cooperate with this structure, a large number of photovoltaic modules need to be boosted in series, and the higher DC bus voltage is gathered as the input pole of the inverter. This will cause the photovoltaic modules that generate electricity to become loads due to inconsistent output characteristics of the photovoltaic modules, consuming power generation, greatly reducing the efficiency of grid connection

[0004] The patent with the notification number CN204334377U discloses a micro photovoltaic inverter based on a flyback transformer, which can improve the distortion of the grid-connected current, but the topology of the micro inverter is complex, and each photovoltaic module output needs A set of independent booster circuit, grid-connected circuit and control circuit has high cost and is not conducive to engineering application

[0005] Series boosting is the simplest and cheapest way to obtain high voltage technology, but the simple series connection of photovoltaic modules loses the power generation efficiency, so it is urgent to provide a new type of photovoltaic inverter to solve the above problems

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