Model predictive control is a promising approach to control a multi-objective modular multilevel converter (MMC). In this approach, the control objectives of MMC are included in a single cost function and evaluated for all possible switching states by using weighting factors. The complexity of weighting factor selection process increases with the number of control objectives, and it affects the performance of MPC as well. To reduce the dependency on the weighting factors, a new model predictive control with zero-sequence voltage injection is proposed. With the proposed approach, some of the control objectives like reduction of submodule capacitor voltage ripple and circulating current can be achieved without using a cost function. The proposed approach also reduces the total harmonic distortion of the output voltage and current waveforms. The performance comparison of the proposed and existing MPC approach has been verified through MATLAB simulations on a three-level flying capacitor (3L-FC) based MMC system.

This paper presents a comprehensive study on the state-of-the-art and emerging wind energy technologies from the electrical engineering perspective. In an attempt to decrease cost of energy, increase the wind energy conversion efficiency, reliability, power density, and comply with the stringent grid codes, the electric generators and power electronic converters have emerged in a rigorous manner. From the market based survey, the most successful generator-converter configurations are addressed along with few promising topologies available in the literature. The back-to-back connected converters, passive generator-side converters, converters for multiphase generators, and converters without intermediate dc-link are investigated for high-power wind energy conversion systems (WECS), and presented in low and medium voltage category. The onshore and offshore wind farm configurations are analyzed with respect to the series/parallel connection of wind turbine ac/dc output terminals, and high voltage ac/dc transmission. The fault-ride through compliance methods used in the induction and synchronous generator based WECS are also discussed. The past, present and future trends in megawatt WECS are reviewed in terms of mechanical and electrical technologies, integration to power systems, and control theory. The important survey results, and technical merits and demerits of various WECS electrical systems are summarized by tables. The list of current and future wind turbines are also provided along with technical details.

This paper presents a new and simple method for capacitor voltages balancing of an n-level diode-clamped multilevel converters using space vector modulation (SVM). The proposed method introduces a generalized approach to calculate dc-link capacitor currents without the use of look-up tables for an n-level diode-clamped converter. This approach balances dc-link capacitor voltages based on minimum energy property. The performance of the proposed method has been studied for a three-level, four-level and five-level diode-clamped converter in MATLAB/Simulink environment.

A new predictive control strategy for current source rectifiers which allows an effective control of source and load currents is presented in this paper. This method uses the commutation states of the converter in the subsequent sampling time according to an optimization algorithm given by a cost function and the discrete system model. The two control goals are: (a) regulation of dc-link current according to an arbitrary reference, and (b) a good tracking of the source current to its sinusoidal reference. The feasibility of the proposed method is verified by MATLAB/Simulink software.