Optimization of the Superconducting Linear Magnetic Bearing of a Maglev Vehicle

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

A Switched Reluctance Motor Drive using Photovoltaic Transistors: Principle, Prototype, Experimental and Numerical Results

International audienceA 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