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This article proposes a novel application method, inverse application of artificial intelligence (IAAI) for the control of power electronic converter systems. The proposed method can give the desired control coefficients/references in a simple way because, compared to conventional methods, IAAI only relies on a data-driven process with no need for an optimization process or substantial derivations. Noting that the IAAI approach uses artificial intelligence to provide feasible coefficients/references for the power converter control, rather than building a new controller. After illustrating the IAAI concept, a conventional application method of artificial neural network is discussed, an optimization-based design. Then, a two-source-converter microgrid case is studied to choose the best droop coefficients via the optimization-based approach. After that, the proposed IAAI method is employed for the same microgrid case to quickly find good droop coefficients. Furthermore, the IAAI method is applied to a modular multilevel converter (MMC) case, extending the MMC operation region under unbalanced grid faults. In the MMC case, both simulation and experimental online tests validate the operation, feasibility, and practicality of IAAI. [ABSTRACT FROM AUTHOR]

Harmonics generated from power electronic converters will impose significant power quality challenges to the electric grid onboard future aircraft. In this article, we propose an innovative modulation scheme that enables using a buck–boost dc–dc converter as a harmonic absorber. To demonstrate the effectiveness of the proposed method, a hybrid power generation system involving a high-speed electrical generator and a high voltage battery is introduced. The electrical generator is connected to a dc bus through an ac–dc converter and the battery to the dc bus with a dc–dc converter. For the studied hybrid power generation system, it is identified that the first carrier frequency side-band harmonic (fc-3f0) from the ac–dc converter is most relevant and is targeted for cancellation. For the control of the dc–dc converter, a new modulation technique, called equal-gate-width modulation is proposed. It allows active control of the magnitude and phase angle of some specific harmonic components from a dc–dc converter. By properly tuning the phase angle and amplitude, the controlled harmonics can thus be used to cancel harmonics from other converters on a common dc bus. Without losing generality, this article focuses on the development of this specific harmonic cancellation scheme and the effectiveness of our proposed methods has been demonstrated using experimental results. [ABSTRACT FROM AUTHOR]

For the direct-current (dc) electrical power distribution system onboard more electric aircraft, the voltage quality of dc bus is of a great concern since there could be significant harmonics distortions when feeding different power electronics loads. This problem can be potentially addressed by introducing a dc filter to the point-of-load converters regulated by the finite control set model predictive control (FCS-MPC). To optimize this filter, genetic algorithm (GA) is utilized for searching the optimal design, which guarantees a low mass and low power losses. Different from the conventional filter design methods, the proposed method treats $LC$ as design variables, which need to be optimized while ensuring the output power quality. First, relations among variables, operation conditions, and constraints are built based on commercial data and circuit simulations. Then, the design and optimization are developed with these relations and a Pareto front is finally given by GA. After that, the best design is obtained by an index integrating two objectives. Lastly, the design approach is verified by an experiment where an FCS-MPC regulated converter was used as a particular example fed by three different LC filters. [ABSTRACT FROM AUTHOR]

This paper presents an overview of technology related to on-board microgrids for the more electric aircraft. All aircraft use an isolated system, where security of supply and power density represents the main requirements. Different distribution systems (ac and dc) and voltage levels coexist, and power converters have the central role in connecting them with high reliability and high power density. Ensuring the safety of supply with a limited redundancy is one of the targets of the system design since it allows increasing the power density. This main challenge is often tackled with proper load management and advanced control strategies, as highlighted in this paper. [ABSTRACT FROM AUTHOR]

This paper describes a high-performance neutral point voltage balancing technique for a neutral point clamped (NPC) converter. Conventional neutral point voltage balancing methods do not function well under low power factor, low pulse ratio, and near-unity modulation index operation conditions. These conditions are essentially dominant operation conditions for aircraft starter/generator systems. This paper introduces an alternative space vector modulation technique for three-level NPC converters in an aircraft starter generator system. The selection of voltage space vectors is optimized for high modulation index and low power factor operation. Disturbances caused by a low pulse ratio are also compensated. The proposed method maintains neutral point voltage balance and ripple minimization over the full range of operating conditions. This paper also provides a detailed analysis of the sources of neutral point voltage imbalances and ripples in high-speed drives with deep flux weakening. Simulation results obtained from a Simulink/PLECS model and experimental results obtained from a 45 kVA, 32 krpm aircraft starter generator test rig prove that the proposed method eliminates the neutral point voltage imbalance and significantly reduces the neutral point voltage ripple. [ABSTRACT FROM AUTHOR]

Stability studies are a crucial part of the design of power electronic systems, especially for safety critical applications. Standard methods can guarantee stability under nominal conditions but do not take into account the multiple uncertainties that are inherent in the physical system or in the system model. These uncertainties, if unaccounted for, may lead to highly optimistic or even erroneous stability margins. The structured singular value-based $\mu$ method justifiably takes into account all possible uncertainties in the system. However, the application of the $\mu$ method to power electronic systems with multiple uncertainties is not widely discussed in the literature. This paper presents practical approaches to applying the $\mu$ method in the robust stability analysis of such uncertain systems. Further, it reveals the significant impact of various types of parametric uncertainties on the reliability of stability assessments of power electronic systems. This is achieved by examining the robust stability margin of the dc/dc buck converter system, when it is subject to variations in system load, line resistance, operating temperature, and uncertainties in the system model. The $\mu$ predictions are supported by time-domain simulation and experimental results. [ABSTRACT FROM AUTHOR]

This article introduces the more electric aircraft concept and investigate the potential benefits of the technology for manned aircraft. Typical aircraft electrical power systems and loads are described as well as the exciting, future challenges for the aerospace industry. The importance of power electronics as an enabling technology for this step change in aircraft design are considered and examples of typical system designs are discussed. [ABSTRACT FROM PUBLISHER]

To improve the design of electric drives and to better predict the system performance, numerical simulation has been widely employed. Whereas in the majority of the approaches, the machines and the power electronics are designed and simulated separately, to improve the fidelity, a co-simulation should be performed. This paper presents a complete coupled co-simulation model of synchronous reluctance machine (SynRel) drive, which includes the finite element model of the SynRel, the power electronics inverter, the control system, and application examples. The model of SynRel is based on a finite element model (FEM) using Simcenter MagNet. The power electronics inverter is built using PLECS Blockset, and the drive control model is built in Simulink environment, which allows for coupling between MagNet and PLECS. The proposed simulation model provides high accuracy thanks to the complete FEA-based model fed by actual inverter voltage. The comparison of the simulation results with experimental measurements shows good correspondence. [ABSTRACT FROM AUTHOR]

In several industrial sectors, induction machines are being replaced with permanent magnet based alternatives, owing to the potential for higher power density and efficiency. However, high-speed applications feature a wide flux-weakening region, where advanced induction machines could bring benefits in terms of system-level optimization. This paper gives an overview the technological challenges for high-speed drives with induction machines, materials, simulations and future challenges for the power electronics in these applications. The target application is a high-speed induction machine for a naval turbocharging system. The comparison with permanent magnet synchronous machines will demonstrate how the extended flux weakening operation effectively allows for a weight reduction of the overall system. [ABSTRACT FROM AUTHOR]