Design
Kinestas develops its electrical machines through a specific process. The first step is the initial design phase where the concept is established, and where we define the EM type, basic parameters and size of the motor. Each electric motor type has a particular performance and field of application, so it is important to make a good decision about the type of motor at the very beginning of the design process.
The division is to AC and DC. AC motors can be synchronous and asynchronous (induction). Synchronous can have a permanent magnet or a wound rotor. Asynchronous motors are mainly used in the industry and in applications where robustness and lower cost is preferred, while permanent magnet motors are used where the highest efficiency is required. The reluctance motors (synchronous or switched), are becoming popular nowadays because they represent a compromise between high performance and low price, so they are typical examples of a cost-driven solution.
A detailed electromagnetic design combining analytics and FEM
The next phase is a detailed electro-magnetic design. At this stage, all electrical parameters and design of the magnetic circuits and winding are defined in detail. The propagation of the electromagnetic field in the machine, different winding configurations are analyzed and efficiency and power loss are checked. For all this, we typically combine analytical equations and FEMM in the so-called hybrid approach which provides calculation speed and accuracy at the same time and thus enables the application of modern optimization algorithms in the later design stage.
Thermal and structural design
In the third phase, thermal and structural designs are coupled with electromagnetic properties. We analyze the thermal performance of the motor and how it affects the motor output. This is coupled with the design of a proper cooling system that enables efficient removal of generated heat inside the motor parts. This also includes the analysis of safety margins for temperatures in critical parts like magnets and wire insulation, as well as mechanical stress in the rotor parts like magnet pockets, rotor slots in induction motors, shaft, bearings, etc. Structural design involves the design of all mechanical parts of the motor including housing with the associated cooling system.
NVH analysis
NVH involves Noise, Vibration and Harshness analysis. In this step we analyze the possible causes of noise and vibration and, if necessary, measures are taken to modify the mechanical and/or electromagnetic design. In this way, we detect potential NVH problems which design might inherently have and do necessary changes in the main design parameters before we go into the optimization process.
Optimization
An electric motor can be optimized by one or more criteria at a time. Kinestas team goes deep into optimization to provide the best performance of our motors. We use well-proven, as well as new optimization techniques in combination with fast motor models. Optimization is done not just according to common optimization goals (higher torque density, lower cost) but also according to customer’s specific requirements.
Prototyping and testing
The last phase is rapid prototyping, as well as testing of electric machines according to standard or customer-specific tests.
