Math Based Approach to Model Active Hall Effect Position Sensors

Active Hall Effect Sensors are used in numerous automotive applications where direction, position, and speed sensing capabilities are required. The primary usage of these devices is in the areas of engine and transmission controls as well as ABS speed monitoring systems. To reliably employ these sensors in such applications requires a thorough understanding of the device electronics and how this component interprets the magnetic fields produced by a ferromagnetic target. The traditional methods involving the construction and test of prototype sensors and targets have been costly, time consuming, and rarely resulted in a robust design. To resolve this problem General Motors Powertrain and Ansoft Corporation have jointly developed the capability to accurately model active Hall Effect Sensors. This paper specifically describes the method developed jointly by these corporations to model a Hall Effect Position Sensor incorporating the material, magnetic, and electrical characteristics of a design. This method of modeling is accomplished through the application of Maxwell®, an Electromagnetic Finite Element (EMFEA) package developed by Ansoft Corporation and Saber™, a Mechatronic Simulator developed by Analogy.