Automatic HF model generation and impedance optimization for low voltage DC motors
Purpose - The purpose of this paper is to create a model to calculate the high frequency (HF) complex impedance of common low-voltage DC motors from construction parameters to predict their electromagnetic compatibility (EMC) emission behaviour and perform sensitivity analyses, and an optimization routine is developed to find combinations of construction parameters which best match a desired impedance curve. Design/methodology/approach - The motor is divided into components. For each component, its electrical behaviour including parasitics is derived from material and geometry, and the electromagnetic interactions between components are defined. These results are then reproduced using inductances, capacitances, and resistors where applicable. Mathematical expressions are given to calculate their value from the material and geometrical parameters. Findings - The complex impedance of DC motors can be accurately constructed from geometry and material parameters within a small range. The optimization routine successfully finds parameters to match a desired curve within specified parameter ranges. This can help finding a motor with lower conducted electromagnetic interference. Originality/value - This analytically parameterized model constitutes a new way to describe electrical motors from an EMC perspective and define critical parameters.