Simplified Model Predictive Current Control of Four-Level Nested Neutral Point Clamped Converter

Abstract

Model predictive control (MPC) is an efficient and growing approach to power converter control. This paper proposes an improved and simplified model predictive current control (MPCC) technique for a four-level nested neutral point clamped (4L-NNPC) converter. Conventional MPCC exhibits better performances as compared to the conventional linear control system such as fast dynamic response, consideration of the system constraints, and nonlinearities. However, the application of the conventional model predictive current control (MPCC) approach on complex systems provokes a significant number of calculations, which is the main hurdle to its practical implementation. To fix this flaw, this paper proposes an effective algorithm to shorten the execution time of the conventional MPCC. In this proposed technique, 216 current predictions of the conventional MPCC are skipped and converted into one required voltage vector (RVV) prediction. With this equivalent reference voltage transformation, the calculation burden of MPCC is significantly reduced, while the output performance is not influenced. The results of the simplified MPCC for the 4L-NNPC converter are analyzed and compared with the conventional MPCC. The computational time is reduced by 19.56% using the simplified MPCC, while keeping an approximately similar error of output currents. The switching frequency and total harmonic distortion (THD) of the proposed method are reduced by 8.16% and 0.07%, respectively, as compared to the conventional technique. These results demonstrate the fact that that the performance of a conventional MPCC is enhanced with the proposed MPCC. The proposed algorithm can be applied to several inverter topologies.

Improved Triple-Voltage-Vector Model-Free Predictive Current Control for Synchronous Reluctance Motor Drives

“…where v is the voltage vector synthesized and modulated by three voltage vectors; v 1 , v 2 , and v 3 denote the initial, second, and third applied voltage vectors. The relevance between the combination of switching states is shown in Table 1, and S 1 , S 2 , and S 3 in the given table correspond to the amalgamations of switching states of ITVV modulation; S [1], S [2] and S [3] represents the initial, second, and third voltage vectors of ITVV modulation. Like the DVV modulation strategy for online duty cycle calculation described in [52], the ITVV modulation has the same two-step design strategy.…”

“…With the advent of microprocessors so much faster and more vital in today's world, it has become possible to implement new and more complex schemes with little difficulty. The model predictive current control (MPCC) is one of these complex schemes which has recently gained considerable attention [1]- [5] in terms of its flexibility and its ability to handle constraints systematically despite their complexity. As MPCC employs an insufficient number of switching states, it is utilized in choosing the ideal switching state via the minimization of objective function control technology.…”

Model Predictive Control for Single-Phase Switched-Capacitor Multilevel Inverters

“…[4], [5]. In general terms, there are three classical configurations for MLIs: neutral point clamped (NPC), flying capacitor (FC), and cascaded H-bridge (CHB) configurations [6], [7], [8]. These three configurations can be divided into three classes: switched DCsource MLIs (SDC-MLIs) like CHB-MLI, switched-diode MLIs (SD-MLIs) like NPC-MLIs, and switched-capacitor MLIs (SC-MLIs) like FC-MLIs.…”