The Design And Implementation Of The Single-phase Grid-connected Inverter For The Fuel Cell

Fuel cell power inverter is a broad prospect of green power generation device, and in the new energy it’s a hot research field. The fuel cell output voltage characteristics are soft with low voltage levels, in the small and medium-sized fuel cell power generation system. Because the required voltage of the grid is generally220V/50HZ AC, the low-voltage must be boost and inverter into high-quality sinusoidal AC power, this paper we regarded single-phase power generation fuel cell system as the study object, and conducted a comprehensive theoretical analysis of the system. We made a detailed analysis and research from the fuel cell power system topology, the network control strategy, and the main circuit parameters selection. The following are the main content of this paper:We chosen the full-bridge main circuit topology for the fuel cell power generation system, and analyzed the full-bridge inverter circuit working principle, and proposed the AC side filter design thinking and processing. This paper modeled the Grid-connected inverter output stage, and derived the open-loop transfer function of the inverter system, and proposed the software control strategies which combined the grid voltage feed-forward and the SPWM current control strategy.This paper designed grid-connected inverter hardware circuitry and software algorithms basined on the TMS320LF2407A processor. The hardware includes signal detection and processing circuit, the high-precision power tube drive circuit and the protection circuit. The software part used the modular programming method, introduced the main program and subroutine flowcharts, focusing on the solving of the SPWM wave generation, the achieving of grid current and grid voltage of the same phase and frequency.This paper analyzed the dual mode of operation of the inverter switching process, proposed and designed an inverter mode switching control strategy. The inverter can work in grid mode of operation; can work in stand alone mode of operation. It could also control and achieve the smooth switching between the two modes of operation. It made the grid interactive use of the fuel cell and the grid, and increased the reliability of power to the load.