Real-Time Implementation of Long-Horizon Direct Model Predictive Control on an Embedded System

Abstract

This paper deals with the real-time implementation of a long-horizon finite control set model predictive control (FCS-MPC) algorithm on an embedded system. The targeted application is a medium-voltage drive system which means that operation at a very low switching frequency is needed so that the switching power losses are kept relatively low. However, a small sampling interval is required to achieve a fine granularity of switching, and thus ensure superior system performance. This renders the real-time implementation of the controller challenging. To facilitate this, a high level synthesis (HLS) tool, which synthesizes C++ code into VHDL, is employed to enable a higher level of abstraction and faster prototype development of the real-time solver of the long-horizon FCS-MPC problem, namely the sphere decoder. Experimental results based on a small-scale prototype, consisting of a three-level neutral point clamped (NPC) inverter and an induction machine, confirm that the algorithm can be executed in real time within the targeted control period of 25 µs.

Heterogeneous Flight Management System (FMS) Design for Unmanned Aerial Vehicles (UAVs): Current Stages, Challenges, and Opportunities

“…Furthermore, Mapping (SLAM) [25], vision sensors are treated as the instance of the sensor side. On the other side, the real-time implementation of the controller presents a challenging task [26]. To further illustrate the notion of heterogeneity, the synergistic development of Permanent-Magnet Synchronous Motor (PMSM) and heterogeneous SoCs as an example of the actuator side is focused on.…”

Long-Horizon Robust Direct Model Predictive Control for Medium-Voltage Induction Motor Drives With Reduced Computational Complexity

“…Notably, the instantaneous value Xσ (see the yellow dash-dotted line) exhibits occasional spikes. These are due to the fact that the estimation scheme relies on the stator current derivatives (see (10)). As a result, the instantaneous estimations can be adversely affected by noise.…”

“…To address this issue, and thus facilitate the real-time implementation of long-horizon FCS-MPC, some methods have been proposed that aim to reduce the computational complexity of the associated optimization problem, such as dedicated branch-and-bound techniques [6], or prediction horizons of nontrivial form [7]. In this direction, and as far as long-horizon FCS-MPC for three-level power converters is concerned, the branch-and-bound strategy called sphere decoder was implemented in real time in [8]- [10]. It is worth noting that the control platform used in [8] was a dSPACE, whereas works [9] and [10] implemented the long-horizon FCS-MPC algorithm on a field-programmable gate array (FPGA).…”

“…In this direction, and as far as long-horizon FCS-MPC for three-level power converters is concerned, the branch-and-bound strategy called sphere decoder was implemented in real time in [8]- [10]. It is worth noting that the control platform used in [8] was a dSPACE, whereas works [9] and [10] implemented the long-horizon FCS-MPC algorithm on a field-programmable gate array (FPGA). Nevertheless, regardless of the control platform, the sphere decoder is executed in a sequential manner, implying that the ability of an FPGA to perform intensive calculations in a highly pipelined and/or parallelized manner was not exploited [11].…”