FPGA-based implementation of digital control for a magnetic bearing

An FPGA-based digital controller is presented for a magnetic bearing control application. A side-by-side comparison of the FPGA- and DSP-based controllers demonstrates the advantages of using an FPGA in terms of design procedures, performance, and hardware utilization. The FPGA-based controller runs two orders of magnitude faster than the DSP-based controller does. The flexibility to customize the bit-widths of the internal variables makes the FPGA-based implementation more accurate than the DSP-based implementation, without increasing total register space. The increased accuracy in the control computation is especially important as fast sampling causes increased computational sensitivity.