High-efficiency inverter topology

Abstract

The invention discloses a high-efficiency inverter topology which inverts direct current into alternating current in a lower cost and high efficiency manner, simultaneously does not cause a common mode interference problem, and can be conveniently applied to inverter systems without isolation transformers. The principle of the topology is that high-frequency chopping switches are respectively arranged on a positive end and a negative end of a direct current input side and switched on/off simultaneously, and the duty ratios of the switches are regulated so as to vary the amplitudes of the output voltage; flat wave inductors are respectively connected at the rear stages of the switches, and a subsequent flow circuit is arranged at one sides, which are connected with the chopping switches, of the two flat wave inductors, so that the subsequent current of the flat wave inductors are ensured when the chopping switches are switched off; H inverting bridges are arranged at the rear stages of the inductors and invert at the output frequency which is required by an inverter, and accordingly, inverting is realized. By utilizing the topology, the switching voltages of switching tubes are reduced, and accordingly, the switching loss of a system is decreased; and moreover, the topology does not cause the common mode interference problem and can be used for the inverter systems without the isolation transformers.

Description

Technical field [0001] The invention belongs to the field of power conversion. It is a topological structure that converts direct current into alternating current. It can be widely used in inverters that require high conversion efficiency or common mode current suppression, such as photovoltaic inverters and wind power inverters. Changer and so on. Background technique [0002] With the development of industry, the requirements for inverter conversion efficiency are getting higher and higher, especially in industries such as new energy power generation, smart grid, and flexible AC and DC transmission. Increasing the conversion efficiency of the inverter can save more electric energy and also reduce the heat dissipation requirements of the inverter itself. The decisive factor of inverter efficiency is the topology of the inverter. The quality of the topology determines the efficiency and cost of the inverter. Inverters in many applications, such as photovoltaic grid-connected in...

AI Technical Summary

Problems solved by technology

However, the inverter topology without a transformer is prone to high-frequency common-mode leakage current between the two sides because there is no isolation between the input and output sides.

Few existing topologies are suitable for transformerless inverters, and each has its own disadvantages

For example, the traditional H-bridge inverter topology has bipolar modulation and unipolar modulation; if bipolar modulation is used, although there is no high-frequency common-mode leakage current problem, its switching loss is high and conversion efficiency is low; If there is a common-mode leakage current problem when using unipolar modulation

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