The Design of Control System for Low-Power Photovoltaic Grid-Connected Inverter
Abstract
This paper introduces the 200W solar PV grid-connected inverter that can directly converted DC that is generated by solar panels to 220V/50Hz of power frequency AC and output to the grid. This system consists of DC / DC converter and DC / AC inverter. The topology of the DC / DC controller with push-pull circuit, the control chip is SG3525; DC / AC inverter with full-bridge inverter circuit that is controlled with DSP.
1 Introduction
21st century, mankind will be faced with major challenges to achieve sustainable economic and social development. The dual constraints of limited resources and environmental protection, energy issues will become more prominent, which is mainly reflected in: 1 energy shortage; 2 environmental pollution; 3 greenhouse effect.
Therefore, human beings in solving the energy problem and achieve sustainable development, can only rely on scientific and technological progress, large-scale development and utilization of renewable and clean energy. Solar has large reserves, the widespread use of economic, clean environment, etc., so the use of solar energy more and more widespread attention, and become an ideal alternative energy. power 200W solar PV grid-connected inverter is elaborated in this paper, it can directly convert DC that is generated by solar panels to 220V/50Hz of power frequency AC and output to the grid.
2 The Circuit Structure and Working Principle of Photovoltaic
Grid-Connected Inverter The circuit structure of solar photovoltaic grid-connected inverter is shown in Fig. 1. In this system, the 62V DC that is the output of solar panels is converted to 400V DC through DC / DC converter, and then is converted to 220V/50Hz AC through the DC / AC inverter. And this system to ensure that 220V/50Hz sinusoidal voltage the grid-connected inverter output synchronized with the grid voltage.
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| The circuit block diagram |
3 The Control Program of the System
The main circuit topology of photovoltaic grid-connected inverter is shown in Fig. 2. This system consists of DC / DC converter and DC / AC inverter. The inverter circuit of the DC / DC converter with push-pull circuit, it will convert 62V DC voltage of solar panels output into a DC voltage of 400V. The main circuit of the DC / AC inverter adopts full-bridge structures, it consists of four MOS tube, and will convert 400V DC to 220V/50Hz AC voltage.
References:
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5. Zeng, Y., Cai, P.: Application of One-cycle Single-stage Control Method in Grid-connected Photovoltaic Inverter. Journal of Power Supply 3 (2011)
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