Search

This paper reviews fault diagnosis and tolerant techniques for improving reliability of automotive motor control systems which consist of an inverter, permanent magnet synchronous motor and sensors. In order to improve reliability of system, the fault diagnosis is the first step once a fault occurs. An accurate and timely detection and protection can prevent fault propagations and catastrophic consequences. The fault tolerant operation is the next counter measure, which is based on redundancy design. In this paper, statistical survey results on occurrence and failure rate of common fault modes are summarized for inverter, electric motor and sensors, respectively. And then, fault diagnosis and tolerant methods for the main fault modes are discussed based on the researches and literatures which are adequate for automotive applications. Finally, a reliability assessment methodology according to fault mitigation and tolerant concepts is introduced and discussed. [ABSTRACT FROM AUTHOR]

This paper proposes an extended structure of a programmable low-pass filter (PLPF) for direct filtering of three-phase variables in automotive AC drives. The PLPF adjusts its cut-off frequency according to the synchronous frequency of the AC motors. Moreover, it compensates gain attenuation and phase delay of the fundamental component signal. The conventional PLPF can only be applied to variables in the stationary reference frame. In order to obtain filtered three-phase variables, an inverse reference frame transformation is required. However, the extended structure, which includes reference frame transformations, can be directly applied to three-phase variables and remove the noise in the earlier stage before transformation. The extended PLPF is more useful for making signal flows clear and intuitive when organizing an algorithm that directly requires three-phase variables. The extended PLPF requires a moderate computational load corresponding with that of the conventional PLPF because its formula is simplified by use of Kirchhoff's law. The reduction in the execution time is critical for implementing the filter based on low-cost microcontrollers. Using case studies, dead-time compensations and open-phase fault detection for AC drives show the effectiveness of the extended PLPF. [ABSTRACT FROM AUTHOR]

This paper designs an observer-based fault detection method with an adaptive threshold for a rotor-position-sensor fault of permanent-magnet synchronous motor drives in an electromechanical brake (EMB). The observer does not fully agree with the real process due to model uncertainties and parameter variations. To avoid missing or false alarms, a key design issue of the proposed detection method is the adaptive threshold, which is determined by analyzing position estimation errors of the observer. Experimental results using a test bench of an EMB show the effectiveness of the designed method. [ABSTRACT FROM PUBLISHER]

This paper quantitatively analyzes inductance estimation errors due to temperature variation and proposes accurate experimental estimation methods considering the temperature distribution of an interior permanent magnet synchronous machine (IPMSM). Accurate knowledge of direct and quadrature-axis inductances is essential for high-performance control of an IPMSM. From the quantitative error analysis results, it is shown that the temperature variation is a very sensitive factor for the accuracy of the experimental estimation of the inductances. For accurate temperature consideration, two experimental estimation approaches are proposed. One uses the temperature measured at end windings to represent the internal temperature of the machine. The other uses both the measured temperature and other temperature information obtained from a temperature distribution analysis. This paper carries out a case study in which the proposed estimation methods are applied to a sample IPMSM with ferrite magnets. Experimental results are compared with finite element analysis (FEA) results in order to verify the effectiveness of the proposed methods. [ABSTRACT FROM PUBLISHER]

This paper analyzes and compensates unavoidable time delay effects in a hardware-in-the-loop (HIL) simulation for automotive permanent magnet synchronous motordrive systems. The amount of time delay between a digital controller and HIL simulator is investigated. The effects of the time delay are analyzed by use of s-domain representation of the entire closed-loop system. In addition, a stability study has been carried out using a root locus. The analysis results show that the time delay strongly affects the accuracy and stability of the HIL simulation according to increment of the motor angular speed. For an accurate HIL simulation, a compensation of the time delays is applied and verified through comparison with offline simulation results. [ABSTRACT FROM AUTHOR]

This paper presents an improved approach for estimating high-resolution rotor position in permanent-magnet synchronous motor (PMSM) drives with low-resolution Hall-effect sensors. A vector-tracking position observer in conjunction with discrete Hall sensors' output signals has been proposed, which is similar to a phase-locked loop structure. It consists of a position error detector, based on the vector cross product of the unit back-electromotive-force vectors obtained from a stator electrical model, and a proportional–integral-typed controller to make the position error rapidly converge to zero. This structure does not only compensate the misalignment effect of Hall sensors but also enhance their transient operating capability. The effectiveness of the proposed approach has been verified from several experiments in a low-voltage PMSM drive for automotive applications. [ABSTRACT FROM AUTHOR]