Considering the need for cost/performance prediction and optimization of superconducting maglev vehicles, we develop and validate here a 3D finite element model to simulate superconducting linear magnetic bearings. Then we reduce the 3D model to a 2D model in order to decrease the computing time. This allows us to perform in a reasonable time a stochastic optimization considering the superconductor properties and the vehicle operation. We look for the permanent magnet guideway geometry that minimizes the cost and maximizes the lateral force during a displacement sequence, with a constraint on the minimum levitation force. The displacement sequence reproduces a regular maglev vehicle operation with both vertical and lateral movements. For the sake of comparison, our reference is the SupraTrans prototype bearing. The results of the optimization suggest that the bearing cost could be substantially reduced, while keeping the same performances as the initial design. Alternatively, the performances could be significantly improved for the same original cost. I. INTRODUCTIONRecently, a full scale superconducting maglev vehicle, named MagLev-Cobra, was successfully demonstrated at the Federal University of Rio de Janeiro, Brazil [1,2]. In order to achieve the superconducting levitation, it uses a permanent magnet (PM) guideway and several cryostats containing YBCO superconducting bulks placed on the bottom of the vehicle. The interaction of the PM guideway static magnetic field with the superconductors produces stable levitation and lateral guidance forces. One issue of this technology is the cost, because of the large amount of rare earth PM used along the entire line. In this context, the optimization of the superconducting linear magnetic bearing (SLMB) focusing on the reduction of PM guideway material used, while maintaining the performances, motivates this work.Lately several models have been successfully developed by different research groups around the world to simulate superconducting magnetic bearings [3,4,5,6,7]. However, their use has been so far generally limited to parametric studies involving few hundred evaluations [8,9]. Indeed the problem is highly nonlinear and intrinsically time-dependent, leading to very large computing time in order to perform the numbers of simulations needed in a stochastic optimization process. This is the reason why, in [10,11], the shape of the PM guideway was optimized considering the superconductor as a perfect diamagnet. A SLMB model based on the critical state approximation was only used in a second step for verification.Besides, in previous works, only vertical motion was considered. But during the regular operation of a maglev vehicle, lateral displacements are to be expected, due to curves for example. This tends to modify the magnetization [12], and as a result to reduce the levitation force and alter the lateral force [13,14]. This should be taken into account during the optimization.We propose here to perform a stochastic optimization of the PM guideway geometry, takin...

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A photovoltaic switched reluctance motor converts light energy into mechanical energy, without power electronics, brushes or magnets. With the rapid decrease of photovoltaic cells price, its simplicity makes it ideal for low cost, autonomous and reliable applications, such as water pumping in isolated areas with good solar irradiation. But the concept does not allow for motion control or variable-speed operation. In order to evaluate its range of application, then to optimize its sizing, we need to understand the complex interactions between the photovoltaic cells and the motor. To this end, we develop here a numerical model of our photovoltaic switched reluctance motor prototype. It takes into account the nonlinearity of photovoltaic cells and of the switched reluctance machine. Despite the uncommon operation of the photovoltaic cells, the agreement between the simulation and the measures is so far good, thus validating our modeling strategy.

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Abstract-A solar-powered switch reluctance motor drive using photovoltaic transistors is presented. The expression "photovoltaic transistor (PVT)" is used to designate a conventional photovoltaic cell used as a light-controlled power transistor. To obtain a motor drive, a set of PVTs controls the current fed from an external DC power source to the motor phases. The control is achieved by modulating the sunlight hitting the PVTs using a shutter driven by the motor rotor. If the external DC source is a solar panel, the resulting system is able to convert light energy into mechanical energy, without the need of any brushes or other power electronics components. This system could be more affordable and reliable than conventional ones, and therefore is well suited for off-grid applications like water pumping. This article first discusses the operation of a photovoltaic transistor through the proposition and the validation of a model. Then, the operating principle of a PVT inverter is clarified. Finally, experimental and numerical results on the first PVT inverter-fed switched reluctance motor are reported. A prototype was built using a switched reluctance motor 6/4 and 12 PVTs. It was here connected to an external 12 V DC power source as a step before using a solar photovoltaic source. Results showed that the PVT inverter-fed switched reluctance motor was operating as expected and provided useful power.