Christoph Datlinger

Rotor position sensing is necessary in electric traction applications to enhance the reliability of control, and inductive-based sensors such as resolvers and eddy current sensors are most used due to their working well in harsh environment. Since the existing methods show some limitations, it is significant to explore the new type of sensor to improve the performance. This paper introduces a novel angular sensor with novel structure based on magnetically coupled resonant principle. It is made using printed circuit board (PCB), consisting of the excitation circuit and receiving circuit located at the stator side, and the feedback circuit located at the rotor side. Besides, the coil of each circuit is in series with corresponding capacitors to make the whole system work at the same resonant frequency. With this structure, the sensor has sufficient output gain without ferromagnetic material used. The working principle and structural design of the sensor are described in detail, and in the finite element analysis (FEA) the coil structure is calculated to preliminarily verify the sensing accuracy, finally a sensor prototype was fabricated for precision test and its sensitivity test with respect to the stator's misalignment. The experiment results show that the peak-to-peak value of the error is within 1° (electric angle) under quasi-static state, 2.234° (electric angle) at the speed of 20000rpm, and the output gain is about 2.6. Moreover, the test of sensitivity to misalignment shows that the air-coupling-based sensor has good sensing stability with non-negligible mounting shift of the stator, to reflect the reliability in harsh conditions.

Rotor shaft position sensors are required to ensure the efficient and reliable control of Permanent Magnet Synchronous Machines (PMSM), which are often applied as traction motors in electrified automotive powertrains. In general, various sensor principles are available, e.g., resolvers and inductive- or magnetoresistive sensors. Each technology is characterized by strengths and weaknesses in terms of measurement accuracy, space demands, disturbing factors and costs, etc. Since the most frequently applied technology, the resolver, shows some weaknesses and is relatively costly, alternative technologies have been introduced during the past years. This paper investigates state-of-the-art position sensor technologies and compares their potentials for use in PMSM in automotive powertrain systems. The corresponding evaluation criteria are defined according to the typical requirements of automotive electric powertrains, and include the provided sensor accuracy under the influence of mechanical tolerances and deviations, integration size, and different electrical- and signal processing-related parameters. The study presents a mapping of the potentials of different rotor position sensor technologies with the target to support the selection of suitable sensor technologies for specified powertrain control applications, addressing both system design and components development.

Due to the increasing electrification of automotive drive train systems, accurate position and speed sensors play an important role to achieve an optimum drive train performance and driving range. These sensor systems determine the rotor shaft position to deliver exact data for efficient drive train control. The system itself must be reliable, sufficiently accurate and cost efficient at the same time. In this way, the design process of the sensor system is influenced by a trade-off, which influences the system performance in view of different parameters, e.g., resolution and data processing accuracy. The focus of the present work is to introduce a method for benchmarking the performance of not only the rotor shaft position sensor, but the whole electric drive train sensor systems by use of a highly accurate reference system on a specifically developed test bench. To achieve a significant benchmark statement by determination of the rotor position angle error, the independent measuring systems, the automotive drive train system and the reference system are synchronized by the use of a common trigger/clock signal. The mentioned signal defines the time steps of the system under test rotor position angle capturing procedure and those of the reference system simultaneously. This enables a common time-base for two independent working measurement systems. This publication provides information about a concept for enhanced rotor position sensor evaluation that enables the merging of real-time data processing with test bench measurement. This procedure provides an important basis for the selection and optimization of position sensor systems for sophisticated electric powertrains.

This paper deals with the evaluation of rotor shaft position sensor systems used in automotive electric powertrain applications. Those sensor systems comprise of an angular rotor position sensor as well as the powertrain's electronic control unit (ECU), processing the sensor data in terms of digitalization, filtering, position- and speed computation. The work introduces an evaluation method of influencing factors on the accuracy of rotor position measurement, e.g. quantization errors, filter settings and time latency of data processing chain. In this way, performance evaluation and investigation of electric powertrain sensor systems is enabled by combination of specific simulation and measurement procedures.