Current Sensor Fault Diagnosis in PMSM Drives Without Additional Hardware

This study proposes an advanced current and position sensor fault diagnosis mechanism for permanent magnet synchronous motor (PMSM) applications. Machine nonlinear dynamics as well as parameter and load uncertainties are addressed. The features of the results of this study are summarized as follows: 1) a proportional-type full-state observer is combined with a disturbance observer to deal with the model uncertainties, 2) a partial optimal process is introduced for determining the observer gain, 3) the concept of normalized residuals is introduced for fault diagnosis criteria, and 4) a closed-loop analysis of the convergence, performance recovery, and offset-free guarantee is provided. The performance recovery property makes the proposed algorithm robust to parameter uncertainties and load variations, and sensitive only to sensor faults. In addition, the location and type of sensor faults can be identified by the fault diagnosis criteria using the normalized residuals. The performance of the sensor fault diagnosis algorithm was experimentally verified under several credible scenarios using a 7.5-kW PMSM.

Reliable fault diagnosis and identification are essential for permanent magnet synchronous motor (PMSM) drive systems with high-reliability requirements. Since open-switch fault and output current sensor fault both affect the residual of output phase current, it is difficult to identify them apart from each other. Thus, this article proposes an open-switch fault and output current sensor fault diagnosis and identification method for the matrix converter (MC)-based PMSM drive system. The finite control set-model predictive control (FCS-MPC) method is applied in the MC-based PMSM drive system. The fault identification method is proposed based on the extracted different faulty features of the open-switch fault and the output current sensor fault. After the open-switch fault is separated from the current sensor fault, an error-voltage-based open-switch fault diagnosis strategy is applied to locate the faulty switch. Hardware-in-the-loop tests are carried out to verify the effectiveness of the proposed method.

For permanent magnet synchronous motors (PMSMs) supplied with a voltage source inverter, current control strategies are commonly implemented under the synchronously rotating reference frame. In order to simplify the system structure, three-phase currents can be measured with a single DC-link current sensor using the phase current reconstruction technique. However, it still needs to follow the conventional AC current control approach. In this paper, a DC-link current control method for PMSMs is proposed to further simplify the control system. The problem of phase current control was separated into the problems of amplitude control and phase control. Then, amplitude control was achieved using a closed-loop controller directly tracking the DC-link current; while phase control was achieved by AC-side pulse width modulation (PWM) following the phase angle of back electromotive force. The compensation for nonlinear distortion of the inverter was taken into account during the control process. Finally, the proposed method realized three-phase current control with a single current sensor and controller, and achieved the purpose of electromagnetic torque control. Experimental results demonstrate the effectiveness of the proposed method.

This paper presented a vector controlled drives of permanent Magnet Synchronous Motor (PMSM) by using Proportional-Integral (PI) Speed controller based dSPACE implementation. The concept of vector control is applied to PMSM to obtain linear dynamics similar to that of a DC motor. The model consist of two control loops, hysteresis current controller is used for inner loop current control and PI controller for outer loop speed control. PI speed controller selected due to simplicity compare to fuzzy, neutral etc. to make sure dSPACE DS1103 successfully implemented. The PMSM vector control algorithm for a theoretical basic has been verified by experimental results and created a rapid control prototype environment by using MATLAB/ Simulink and the DS1103 DSP of dSPACE.

For the N-module permanent magnet synchronous motor (PMSM) drive system, the same phase currents of different submodules can be redundant with each other for closed-loop control. Fast and accurate replacement of currents measured by faulty current sensors is essential for the highly reliable operation of the system. In this article, a similarity learning-based fault diagnosis method for N-module PMSMs is proposed to achieve faster fault detection than traditional methods. Also, the proposed method can accurately identify all 48 fault combinations of current sensors in the faulty submodule. In particular, a hybrid metric distance (HMD) is designed to extract the different characteristics of the coaxial reference voltage based on a modified coordinate transformation of the different axis directions. Based on the HMD, an accumulative sum trigger value (ASTV) method is designed to accurately locate faulty submodules and sensors in case of gain and zero-offset faults. Based on the discrete Laplace operator can accurately locate the faulty submodule and sensor in case of signal loss and stuck faults. In addition, the discrete Laplace operator is combined with the half-wave symmetry variable for fault-type identification. The performance of the proposed method for single-current sensor and dual-current sensor fault diagnosis is experimentally verified in a four-module PMSM driver.

This paper presents advanced torque and current control techniques for Permanent Magnet Synchronous Motors (PMSMs) with a real-time simulator which has a nonlinear motor model. This model is called a “behavior motor model” and is developed based on finite element analysis results to take into account nonlinear characteristics including spatial harmonics and magnetic saturation. The real-time simulator is implemented within a circuit simulator coupling the behavior motor model with switching circuits in real time and it can be applied to torque and current control as an advanced controller. In this paper, the torque and current control of a PMSM with the proposed system is presented. Effectiveness of this technique is verified by performing some simulations and experiments.

This article presents a Permanent Magnet Synchronous Motor (PMSM) sensorless control system using backstepping control. The Extended State Observer (ESO) is also used to perform the sensorless control, and to estimate the load torque which is considered an external disturbance of the control system. Starting from the classic Field Oriented Control (FOC) type PMSM control structure, the classic PI speed and current controllers i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> , i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</sub> are replaced by a backstepping control structure. The main blocks used for the implementation and numerical simulation in the Matlab/Simulink graphical programming environment are presented. The very good static and dynamic performance obtained through numerical simulations even at high speeds, step variations of the value of the load torque, uniformly distributed noise, and variations of the PSMS nominal parameters can be explained by the fact that the backstepping control is applied to the non-linear system of the PMSM and by the step-by-step method of achieving each iqref, ud and uq control by using a Lyapunov-type function. Future articles propose the approach of real-time implementation of the PMSM sensorless control by using the backstepping control.

A system-on-a-programmable-chip (SOPC) using an Altera FPGA (Stratix EP1S10) and a Nios embedded processor to develop drive system for permanent magnet synchronous motor (PMSM) is presented in this paper. In this SOPC, it has two modules to construct a fully digital drive controller. One module performs the function of the speed/position loop control and motion trajectory control of PMSM drives. The other module performs the function of the current loop control for PMSM drives, which includes vector control, SVPWM generation, coordinate transformation, PI controller and the pulse detection of the quadrature encoder. The former is implemented by software using Nios embedded processor due to the need of complicated control algorithm and low sampling frequency control (motion trajectory control & position control: less than 1kHz). The latter is implemented by hardware due to the need of high sampling frequency control (current loop: 16 kHz, PWM circuit: 4/spl sim/8 MHz) but simple computation. To confirm the effectiveness of the proposed SOPC, an experimental system with a PMSM, a FPGA experimental board, an inverter and a rectifier has been set up and some experimental results have been validated with the theoretical ones.

Fault probability rises with an increase in the number of current sensors in multi-phase permanent synchronous motor (PMSM) drives. This paper proposes an improved axis rotation method for fault diagnosis and tolerant control to make the multi-phase PMSM drives against current sensor loss signal and gain faults. This method can effectively diagnose and distinguish faults without selecting a threshold value, and the degree of fault can be further estimated. The proposed method makes current sensor fault diagnosis and tolerant control become an integrated module. The validity and accuracy of the proposed method is verified by different fault diagnoses and tolerant control experiments of a 9 kw nine-phase PMSM drive.

Five-phase permanent magnet synchronous motor (PMSM) is wildly used in the applications with high reliability requirement because of the ability of fault tolerance. Single-phase coil inter-turn short circuit (ITSC) fault is one of the most common faults of PMSM. When PMSM keeps operating under coil ITSC fault condition, the interaction between short circuit current and magnetic field of rotor permanent magnet will generate fault electromagnetic torque, which will cause speed ripple. In this paper, the generation of the fault electromagnetic torque of five-phase PMSM with single-phase coil ITSC fault is theoretically analyzed, and a single-phase coil ITSC fault-tolerant control strategy based on speed ripple compensator (SRC) is proposed. The SRC, which has the advantages of simple structure and less computational burden, can suppress pulsating components of different frequency in the speed ripple caused by the fault electromagnetic torque at the same time without changing the control parameters. The simulation results show that the torque ripple and speed ripple can be reduced significantly by the SRC.

Control of the current harmonics is a critical issue for dual three‐phase (DTP) permanent magnet synchronous motors (PMSMs). Considering the limitations of conventional synchronous frame proportional‐integral (PI) current regulator, this paper presents a hybrid current controller that combines the PI current regulator with a multiresonant controller. With the proposed hybrid current controller, precise current control can be achieved with only a slight increase in the computational effort. Theoretical analysis and experimental results confirm the effectiveness of proposed current controller. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.

This paper proposes an innovative current control strategy for permanent magnet synchronous motor (PMSM) drives with both isotropic and anisotropic rotors, based on Pontryagin's time optimal control (TOC) theory. The control strategy assures the fastest current response after any demanded torque reference variation. It can be demonstrated that such a control exhibits faster response than hysteresis control, even if the latter is often considered the fastest control scheme. The theoretical principle of TOC is at first illustrated. It is then applied to PMSM drives and verified by simulations. Comparison to other control strategies is included in the paper. At last, an experimental validation is carried out and measured results are presented and discussed.

This chapter describes the sliding-mode control of permanent magnet synchronous motor (PMSM) servo systems. The typical structure of the systems consists of the position, velocity, and current control loops. The design of three controllers, position controller, speed controller, and current controller, and a filter in speed loop has been described respectively, aimed at reaching high-performances of PMSM servo systems, such as fast response, strong robustness, and high precision. The digitization of terminal sliding-mode (TSM) controllers of PMSM servo system has been discussed for the purpose of practical implementation.

This paper reports a novel position detection method for permanent magnet synchronous motors (PMSM) operating at standstill and low speed via the application of carrier phase-shifted PWM technology. And also a polarity identification method for PMSM in a rotary frame along with the position detection by using the neutral voltage is proposed. The new technique identifies PMSM motor position from simple measurements on the neutral point voltage which affected by the variation of inductances in responding to rotor position. Then, along with the current vector control, the developed methods are applied in driving a PMSM start at standstill and low speed. The theoretical analysis results are verified by the experimental data obtained from tests at different rotor positions within one electrical cycle during operating of both standstill and low speed.

Online monitoring and diagnostics of permanent magnet synchronous motors (PMSMs) is becoming important with the increasing demand in PMSM applications. Most of the research effort focuses on motor current signature analysis (MCSA) as it can provide remote, online monitoring at low cost. However, all types of defects that produce asymmetries in the PMSM rotor or load produce identical rotor rotational frequency components. This is a serious limitation when applying MCSA since it can produce false indications and degrade the sensitivity of fault detection. The requirement of complex time-frequency analysis techniques is another limitation of MCSA for applications with speed variations. In this paper, the feasibility of using analog Hall sensor signals to complement MCSA for detection and classification of rotor- and load-related defects is investigated. It is shown that Hall sensors installed in machines for initial rotor position estimation can be used with minimal hardware modifications to detect and classify signatures produced by the rotor and load for cases where MCSA fails, even during transient conditions. Experimental testing performed on an interior permanent magnet synchronous motor (IPMSM) under eccentricity, local demagnetization, and load unbalance conditions shows that the reliability and sensitivity of fault detection in PMSM systems can be improved at low added cost.