This chapter details the design of a new innovative solid bar winding for electrical machines (either motors or generators) dedicated to the electric propulsion. The goal of this new winding technique is to enhance the performance by better utilizing the stator slot and increasing the copper fill factor to higher than 75%, and also to reduce the inactive copper at the end-windings. Accordingly, many advantages arise from the application of this solid bar winding: higher torque-to-weight ratio, better thermal behavior, lower rotor losses, higher efficiency, higher reliability and lower cogging torque. However, the solid bar has its inherent constraints, which should be considered with care when designing an electric motor: the AC copper losses and the manufacturing process. The suggested winding technique aims at addressing these challenges.
Part of the book: Emerging Electric Machines
Electric vehicles are often designed in the same way as their conventional counterparts based on the internal combustion engine, they are heavy machines for comfort and safety reasons, and increasingly powerful. Under these conditions, in order to simplify the motor electrical supply system by reducing the current levels, the voltage chosen for the battery is very high and can go up to 700 V. However, for many applications where the power is relatively low (< 30 kW per motor), it can be more beneficial to size the system at very low voltage (< 60 V). This approach allows to overcome many constraining safety requirements and also to use off-the-shelf components (motor controllers, connectors, etc.) that are more easily available on the market in this voltage range. There are also many regulatory provisions that may require to stay within this voltage limit. This article presents a variety of very low voltage motorisation solutions with a required power up to 100kW. They use two complementary approaches. The first is to implement an original permanent magnet synchronous machine technology with an optimised armature winding for low voltage operation. The second is based on power splitting where the electrical machine being designed to be driven by multiple controllers. Many examples of low-voltage motorised vehicles (sporty vehicle, tractor, re-motorised automobile, etc.) are illustrated in this article.
Part of the book: New Perspectives on Electric Vehicles