High power and high step-up ratio photovoltaic DC converter device and control method

Abstract

The invention discloses a high-power and high-step-up ratio photovoltaic DC converter device and a control method. An intermediate frequency 400Hz transformer-based high-power and high-step-up ratio photovoltaic DC converter device with low cost and high efficiency is firstly provided. The high-power and high-step-up ratio photovoltaic DC converter device comprises a multi-channel boost DC transformer, a modular parallel photovoltaic inverter, an intermediate frequency 400Hz three-winding boost transformer, three-phase diode rectifier bridges and high-voltage filter circuits. A control method is disclosed according to the converter device. According to the control method, voltage of an output end of a photovoltaic array is firstly adjusted by using the boost DC transformer, so that the power of the output end of the photovoltaic array is adjusted, and then the power of the output end of the photovoltaic array is transmitted to a transformer side through double loop control of AC / DC side voltage and bridge arm side inductance current of the modular parallel photovoltaic inverter and is transmitted to the final high-voltage DC bus through transformer boosting conversion, diode rectification and the high-voltage filter circuit.

Description

technical field [0001] The invention relates to a photovoltaic DC converter device and a control method, in particular to a photovoltaic DC converter device with high power and high step-up ratio and a control method. Background technique [0002] In recent years, with the continuous development of new energy technologies, photovoltaic power plants will continue to develop in the direction of high power. The capacity of a single photovoltaic power station will reach the GW level, and the AC cable will exceed 100 kilometers. The mutual coupling between a large number of inverters and long-distance cables, the long-distance transmission reduces the overall efficiency of the system, and increases the investment cost. The coupling problem between multiple inverters makes the stability of the AC grid continuously decline. The losses and costs of the grid further increase. [0003] On the other hand, with the development and maturity of power electronics and DC transmission tech...

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is to overcome the limitations of the above-mentioned various technical solutions, and the high-power high-voltage DC photovoltaic converter for large-scale photovoltaic power plants has a small monomer capacity, high DC step-up ratio difficulty, low conversion efficiency, and high cost , low reliability, difficulty in making medium-frequency high-power magnetic components, high cost, etc., to provide a high-power high-step-up ratio photovoltaic DC converter device and control method

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