Long-Horizon Finite-Control-Set Model Predictive Control With Nonrecursive Sphere Decoding on an FPGA

Long-horizon finite-control-set model predictive control is implemented on a field-programmable gate array (FPGA). To solve the underlying least-squares integer program, a nonrecursive sphere decoding algorithm is developed. By exploiting the problem structure, few multipliers are required, and the algorithm computes the optimal solution in a few clock cycles, thus achieving a resource-efficient implementation on the FPGA. For a prediction horizon of five steps and a three-level converter, 87 digital signal processor blocks, and an execution time of at most 3.4μs was required to solve the optimization problem during steady-state operation. Experimental results verify the effectiveness of the long-horizon controller.