A method for torque-ripple compensation in non-ideal permanent magnet machines

Real permanent magnet synchronous machines often suffer from significant deviations from ideal ones. They usually occur as the result of simplified and cost-effective manufacturing, but they are also the source of performance degradation. The main problem is the torque-ripple, which is inadmissible in most of the applications. This paper analyses the main sources of this torque-ripple and presents a method to compensate it. The technique used is based on measurements and off-line calculations, followed by real-time control algorithms. The effectiveness of the method is demonstrated on an experimental setup.