Microinverter for thermoelectric generators for combined feed-in to AC grids and low-voltage battery storage systems

Abstract

The use of thermoelectric generators in stationary applications, for example in heating systems such as pellet heaters or industrial systems with a high amount of waste heat, represents an interesting opportunity to increase the overall process efficiency of these systems. [1] [2] However, the utilization of the generated electrical energy poses a challenge, as the thermoelectric generators supply a low DC voltage, but most of the loads are connected to the AC grid. In addition, the available waste heat is not necessarily available at the same time as the electrical demand of the building. To address this problem, a microinverter is presented that realizes the highly efficient conversion of low DC voltage into AC voltage. The system also has two maximum power point trackers (MPPT) to enable thermoelectric modules to be operated separately and efficiently in different temperature areas. The microinverter also has a module for easy connection to 12V, 24V and 48V battery storage systems. This means that the generation and feed-in of electrical energy can be easily decoupled in terms of time and adapted to the respective demand. The microinverter for thermoelectric generators can be operated in a similar way to the corresponding standards applicable for small solar power plants. [3,4] The system can be easily retrofitted anywhere by plugging it into a standard domestic socket. The maximum feed-in power is 600W. The publication presents the choice of electronics topology and the operating concept. The semiconductor technologies, performance and efficiency data are presented.