This article provides a definition of the availability of electrical machines and a method to calculate it. The objective is to propose a method of classifying electrical machines according to their availability and to extract from them the most suitable for applications where the failure of the machine would be critical. The main result of this study is that open-winding machines have the highest level of availability among the studied machines. It also very clearly confirms, through rigorous quantification, that increasing the number of phases improves the availability of electrical machines.

The synchronous reluctance machine is a promising technology in the electrical machine market. They are now considered in various applications such as transportation or industries. Despite the lack of magnet in such machines, a small residual flux may remains in the ferromagnetic material. This residual flux produces back-electromotive forces as the machine rotates. In this paper, two methods are proposed to determine the back-electromotive forces of the machine online. One is based on the measurements of the short-circuit currents, the other utilizes a linear disturbances observer. The estimations of the back-electromotive forces are then used in the control of the machine in order to compensate their undesirable effects such as current ripples. Both techniques require only the knowledge of the speed and classical electrical parameters of the machine. Experimental results are shown to prove the effectiveness of the proposed approaches.

This paper proposes a generalized averaging 1stharmonic state space model for Dual Active Bridge (DAB) converters fitting any triple phase-shift (TPS) modulation as well as classical modulation schemes. The model provides an analysis about steady state and AC behavior and about operating characteristics like RMS current and conducted emissions. Comparison of results with a full order SPICE simulation show a good agreement as well as with regard to the dynamic behavior prediction. With TPS modulation being the most effective means for optimizing the DAB's efficiency, the proposed approach avoids classical implementations' typical drawbacks such as the need for multiple models corresponding to the mapping of different operating space regions with respect to modulations or the need to pre-constrain control variables to specific switching modes. It can also help reduce the impact of large signal transients on the output filter or of the converter performance degradation with aging. The proposed model is suitable for designing a non-linear control scheme allowing better converter performances in relation to a classical one. The interest and accuracy of the proposed approach are shown through a 150W, 28V to 12V DAB design used for a flight computer power supply where the versatility in controller design and the converter efficiency optimization are required.

A novel scheme to supply AC motor drive with a boost function has been proposed. Different from the classic scheme for a three-phase two-level inverter, the main idea of this so-called Neutral Point Supply (NPS) scheme is to move the power supply to the neutral point of machine. It allows to have the capability of boosting DC-bus voltage without adding semiconductor components to inverter. The objective of this paper is to make an in-depth study of this scheme through a permanent magnet synchronous machine (PMSM) drive. Firstly, the principle of the NPS scheme is studied. Then the corresponding control strategy is presented. Meanwhile, the RMS phase currents and additional losses in machine are studied respectively. The effectiveness of a NPS scheme for PMSM drive is demonstrated by simulation.

A hybrid Lyapunov control for a flying capacitor multicellular converter is presented. This control law is based on the Port-Hamiltonian (PH) formalism of power converters and allows to enhance load current quality and reduce switching losses. The proposed control is applied to a three-cell multicellular converter. A procedure for selecting the best weighting parameters in the control law according to a performance criterion is presented. The simulation and experimental results indicate the stability of the control for changes in the reference signals. A comparison with a different Lyapunov control technique shows the performance of the proposed solution and the advantage of such a strategy in order to reduce the switching losses.

The Finite Control Set Model Predictive Control (FCS-MPC) technique is worldwide recognized due to its adaptability and capacity to take into account the discrete characteristics of control systems. However, it shows some limitations when directly used to control power converters, as its variable frequency spectrum, its limited current quality and its low-voltage precision for a given sample time. Therefore this paper presents an improved hybrid Pulse Width Modulation (PWM) technique based on FCS-MPC, that uses the FCS-MPC theory to select the PWM sequence applied on an inverter at each sample time. The choice on the finite set of PWM sequences is made through a trade-off between the minimization of the switching losses and load current distortion. Simulation results are presented to support the developed technique and show some promising results with appreciable reduction of the switching losses.

Magnetic shape memory alloys (MSMA) are relatively new active materials but at this time they are not actually very used as actuators despite a high strain and a small response time. This is probably due in part to a large hysteresis and a strong non-linear behaviour. In this paper, an original hybrid control is designed taking into account dynamical effects and hysteretic behaviour in order to increase static gain of the system. After a short presentation of MSMA behaviour, a modelling is proposed to obtain two different control strategies. Some experimental results are also given.