Application of a Buck-Boost Converter for Highly Dynamic Power Smoothing in Industrial Applications

Inhalt:
This paper gives attention to the smoothing of maximum power peaks of a load by means of using a dynamic energy storage system. It deals with a metal forming machine tool, which shows comparatively high power peaks during one forming process. The power drawn from the grid while the machine is operating shall be reduced to the mean power consumption of the load. The used energy storage system, which consists of a bidirectional dc-dc converter and electrolytic capacitors, is connected to the dc-link of the forming machine. If the instantaneous power consumption is higher than the mean power consumption of the machine, the difference is provided by the energy storage, otherwise the capacitors are charged. This behavior is realized through the interaction of a PI-based voltage, power and current control. In addition, an approach of connecting a lead acid battery as chemical energy storage was performed to provide the mean power consumption instead of from the grid. This enables the use of renewable energies like photovoltaic energy in combination with energy storages. The performance of the energy storage system is proven by experimental tests. Measurements validate the theoretical considerations and results.