A Low-Complexity Optimal Switching Time-Modulated Model-Predictive Control for PMSM With Three-Level NPC Converter

Conventional finite control set model-predictive control (FCS-MPC) presents a high computational burden, especially in three-level neutral-point-clamped (NPC) converters. This article proposes a low-complexity optimal switching time-modulated model-predictive control (OST-M2PC) method for a three-level NPC converter. In the proposed OST-M2PC method, the optimal switching time is calculated using a cost function. Compared with the conventional FCS-MPC, the proposed OST-M2PC method has a fixed switching frequency as well as better power quality. The proposed OST-M2PC can operate at a 20-kHz sampling frequency, reducing the computational burden of the processor. Simulation and experimental results validate the operation of the proposed method

A Novel Stochastic Predictive Stabilizer for DC Microgrids Feeding CPLs

In this work, a novel nonlinear approach is proposed for the stabilization of microgrids (MGs) with constant power loads (CPLs). The proposed method is constructed based on the incorporation of a pseudo-extended Kalman filter (EKF) into stochastic nonlinear model predictive control (MPC). In order to achieve high-performance and optimal control in dc MGs, estimating the instantaneous power flow of the uncertain CPLs and the available power units is essential. Thus, by utilizing the advantages of the stochastic MPC and the pseudo-EKF, an effective control solution for the stabilization of dc islanded MGs with CPLs is established. This technique develops a constrained controller for practical application to handle the states and control input constraints explicitly; furthermore, as it estimates the current by using the pseudo-EKF, it is a current-senseless approach. As noisy measurements are taken into account for the state estimation, it leads to a less conservative control action rather than the classical robust MPC, whereas it guarantees the global asymptotic stability in the presence of noisy measurements and parameter uncertainty. To validate the performance of the proposed controller, the attained results are compared with state-of-the-art controllers. Furthermore, the implementability of the proposed method is validated using real-time simulations on dSPACE hardware

Penerapan Flower Pollination Algorithm dengan Teknik Clustering dalam Penyelesaian Masalah Diophantine

Permasalahan Diophantine adalah suatu permasalahan yang diwakili persamaan atau sistem persamaan yang memerlukan bilangan bulat non-negatif sebagai solusi. Permasalahan ini banyak dijumpai di berbagai bidang termasuk Computer engineering seperti pengelolaan jaringan dan sinyal. Akan tetapi belum ada metode umum yang secara efektif dapat menyelesaikan permasalahan Diophantine.  Tujuan utama dalam penelitian ini adalah untuk melakukan penyesuaian metode FPAC agar FPAC tidak hanya dapat digunakan pada permasalahan Multimodal tetapi juga dapat dijadikan sebagai alternatif pada permasalahaan Diophantine. Transformasi persamaan ataupun sistem persamaan ke dalam bentuk fungsi optimasi dan transformasi output bilangan real ke bilangan bulat pada setiap tahapan algoritma merupakan kunci utama FPAC dalam menyelesaikan permasalahan Diophantine. Hasil penelitian ini menunjukan bahwa FPAC dapat menemukan seluruh solusi dari persamaan Diophantine baik persamaan yang memiliki jumlah variabel dan pangkat yang berbeda maupun persamaan dalam bentuk eksponensial.  FPAC juga dapat menemukan seluruh solusi yang tersedia pada sistem persamaan Diophantine baik yang berdimensi rendah (kasus 1) maupun dimensi tinggi (kasus 2 dan 3). Secara umum, FPAC terbukti efektif dalam menyelesaikan permasalahan Diophantine baik dalam bentuk persamaan maupun sistem persamaan yang memiliki solusi tunggal maupun jamak dalam sekali running

Decentralized Finite Control Set Model Predictive Control Strategy of Microgrids for Unbalanced and Harmonic Power Management

In this paper, a modified decentralized finite control set model predictive control (FCS-MPC) scheme for the distributed energy resources (DERs) is proposed to improve the power management quality of the prosumers integrated microgrids under the condition of harmonic and unbalance loads. The proposed control strategy for the microgrids mainly consists of the power droop controller, the model predictive controller delay compensation, feedback correction and the unbalance compensation mechanism. The feedback correction method is used to correct the delay compensation, which effectively reduces the average switching frequency (ASF) and voltage total harmonic distortion (THD). By sharing the negative sequence reactive power of the microgrid, power distribution between the prosumers’ DERs is improved. The DERs in the prosumers can be integrated without any communication wire. The transient response and robustness to parameter changes are far superior to hierarchical cascaded control. Moreover, the proposed control strategy can better suppress harmonic and reduce and share fundamental negative sequence reactive power under microgrid unbalance and nonlinear load conditions. Finally, the effectiveness of the proposed FCSMPC control strategy is validated by time-domain simulation results and real-time tests with RT-Lab under the condition of unbalanced and nonlinear loads in the microgrids.Department of Education of Guangdong Province New and Integrated Energy System Theory and Technology Research Group; Brunel Research Initiative and Enterprise Fund BRIEF; National Natural Science Foundation of China; Operation Fund of Guangdong Key Laboratory of Clean Energy Technolog

Voltage Source Converter based Hybrid STATCOM for Reactive Power Compensation in Utility Grid

The availability of high voltage, high current and high-speed power electronic devices has led to increase in popularity of several power electronic applications such as FACTS. A STATCOM is one such power electronic converter, from the FACTS family, which can be used to improve the power factor of a transmission line, maintain the connected bus at the required voltage level, etc. In distribution power level, D-STATCOMs are used to achieve the same objectives. Several power converter topologies have been proposed for STATCOMs and D-STATCOMs, ranging from a standard two-level VSC based topology to a cascaded full-bridge based topology. The cascaded full-bridge based topology might be suitable for high power STATCOM applications but might not be the best option at the lower power level of a D-STATCOM. D-STATCOMs therefore often use a standard two-level converter-based topology owing to cost constraints. The research work presented in this thesis proposes a new power electronic topology which can be used for D-STATCOM applications. This topology is essentially composed of multiple cascaded h-bridge cells in each phase of a standard two-level converter. The two-level converter provides bulk of the power output and operates at a low switching frequency, whereas the h-bridge cell operates at a higher switching frequency and achieve power quality objectives. This research work initially presents simulations to validate the proposed topology. Outer control is proposed to operate the proposed topology as a D-STATCOM. Inner control loops are proposed to maintain the DC-link voltage of the h-bridge cells. An experimental prototype of the proposed topology is also developed. The results obtained from the proposed topology are compared with that obtained from a standard two-level converter-based topology. It is shown that due to the h-bridge cell action in the proposed topology, the obtained current THD is low in comparison to a standard two-level VSC based topology being used as a D-STATCOM