Comparison of DC-link and matrix converters for wind PM generator in weak grid systems

Abstract

In weak grid systems that wind power has a significant portion of the power, connecting wind generator output to the network is an important issue. Direct AC to AC converters have become an attractive option for this purpose. They are replacing conventional AC-DC-AC systems and also being used in various industrial applications. These direct converters have more adaptability between input and output characteristics especially when both input and output are not predictable. In this paper the use of two different bidirectional converters in a weak grid system will be studied, DC-Link as an indirect converter and Matrix as a direct converter. The output of a wind power permanent magnet generator (PMG) is first connected to the grid via a DC-Link converter and then the converter is being replaced by a matrix converter (MC). In each step the operation of the system is simulated and the results are compared with each other. Different parameters such as performance, response speed, voltage and frequency regulation and power quality in the operation band are evaluated.