Recently, an efficient multistep direct model predictive control (MPC) scheme for power converters has been proposed. It relies on the Sphere Decoding Algorithm (SDA) to solve the associated long-horizon optimal control problem. Since the SDA evaluates only a small number of candidate solutions to find the optimal one, a significant reduction in the average computational burden can be achieved compared to the basic exhaustive search approach. However, this is only true during steady-state operation. In fact, the SDA still requires a large execution time during transients. This paper shows that if not properly addressed, the dynamic performance of the system may be degraded, which clearly limits its practical application. To mitigate this issue, which particularly arises during transients, an efficient preconditioning approach for the SDA is proposed. This approach ensures that only a small number of candidate solutions are evaluated during both steady-state, and transients. This allows the multistep direct MPC to become a viable control alternative for power converters operating at low semiconductor switching frequencies, e.g., below 450 Hz. The proposal is validated using a grid-connected three-level converter as a case study. Both processor-in-the-loop simulations, and experimental results on a scaled-down 2.24 kVA laboratory setup are presented.

中文翻译：

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为电源转换器的瞬态操作启用多步模型预测控制

最近，已经提出了一种用于功率转换器的有效的多步直接模型预测控制（MPC）方案。它依靠球面解码算法（SDA）来解决相关的长视距最优控制问题。由于SDA仅评估少量候选解决方案以找到最佳解决方案，因此与基本的穷举搜索方法相比，平均计算量可大大减少。但是，这仅在稳态操作期间适用。实际上，在瞬态过程中，SDA仍然需要大量的执行时间。本文表明，如果解决不当，系统的动态性能可能会降低，这显然限制了其实际应用。为了减轻这个问题，尤其是在瞬态过程中，提出了一种有效的SDA预处理方法。这种方法可确保在稳态和瞬态期间仅评估少量候选解决方案。这使得多步直接MPC成为在低半导体开关频率（例如，低于450 Hz）下工作的功率转换器的可行控制替代方案。该提案已通过并网三级转换器作为案例研究进行了验证。展示了处理器在环仿真以及按比例缩小的2.24 kVA实验室设置的实验结果。低于450 Hz。该提案已通过并网三级转换器作为案例研究进行了验证。展示了处理器在环仿真以及按比例缩小的2.24 kVA实验室设置的实验结果。低于450 Hz。该提案已通过并网三级转换器作为案例研究进行了验证。展示了处理器在环仿真以及按比例缩小的2.24 kVA实验室设置的实验结果。