A novel approach of torque ripple estimation by inverter generated current slope evaluation in interior permanent magnet synchronous machines

The following work describes a new method for estimating the torque ripples of an interior permanent magnet synchronous machine (IPMSM) by estimating the machine parameters within one PWM cycle using the current slopes caused by the switching of the inverter. The use of test signals and filter-based approaches is avoided. In the first paragraph the state-of-the-art torque estimation algorithms are presented and the difference to the new method explained. Following, the theory of the torque equation is derived and the solution of this equation under the consideration of the different switching states of the inverter is investigated. Finally, all presented theoretical results are validated with measurement results on the test bench.