Three-wheel air turbocompressor for PEM fuel cell systems

The present invention generally relates to fuel cell systems and, more particularly, to a fuel cell system that utilizes a pair of parallel turbines engaged to a compressor for increased system efficiency. A fuel cell system comprises a compressor and a fuel processor downstream of the compressor. A fuel cell stack is in communication with the fuel processor and compressor. A combustor is downstream of the fuel cell stack. First and second turbines are downstream of the fuel processor and in parallel flow communication with one another. A distribution valve is in communication with the first and second turbines. The first and second turbines are mechanically engaged to the compressor. A bypass valve is intermediate the compressor and the second turbine, with the bypass valve enabling a compressed gas from the compressor to bypass the fuel processor.