Power electronics plays an important role in a wide range of applications in order to achieve high efficiency and performance. Increasing efforts are being made to improve the reliability of power electronics systems to ensure compliance with more stringent constraints on cost, safety, and availability in different applications. This paper presents an overview of the major failure mechanisms of IGBT modules and their handling methods in power converter systems improving reliability. The major failure mechanisms of IGBT modules are presented first, and methods for predicting lifetime and estimating the junction temperature of IGBT modules are then discussed. Subsequently, different methods for detecting open- and short-circuit faults are presented. Finally, fault-tolerant strategies for improving the reliability of power electronic systems under field operation are explained and compared in terms of performance and cost.

Study and Handling Methods of Power IGBT Module Failures in Power Electronic Converter Systems

In conventional direct torque controlled (DTC) permanent magnet synchronous motor drive, there is usually undesired torque and flux ripple. The existing literature have proposed some methods to reduce torque and flux ripple by optimizing the duty ratio of the active vector. However, these methods are usually complicated and parameter dependent. This paper first compares the performances of three duty determination methods in detail and then proposes a very simple but effective method to obtain the duty ratio. The novel method is superior to the existing methods in terms of simplicity and robustness. By appropriately arranging the sequence of the vectors, the commutation frequency is reduced effectively without performance degradation. To further improve the performance of system, a low-pass filter-based voltage model with compensations of amplitude and phase is employed to acquire accurate stator flux estimation. The proposed scheme is able to reduce the torque and flux ripple significantly while maintaining the simplicity and robustness of conventional DTC at the most. Simulations and presented experimental results validate the effectiveness of the proposed schemes in this paper.

Direct Torque Control of Permanent Magnet Synchronous Motor With Reduced Torque Ripple and Commutation Frequency

Three-phase inverters are currently utilized in an enormous variety of industrial applications, including variable-speed ac drives. However, due to their complexity and exposure to several stresses, they are prone to suffer critical failures. Accordingly, this paper presents a novel diagnostic algorithm that allows the real-time detection and localization of multiple power switch open-circuit faults in inverter-fed ac motor drives. The proposed method is quite simple and just requires the measured motor phase currents and their corresponding reference signals, already available from the main control system, therefore avoiding the use of additional sensors and hardware. Several experimental results using a vector-controlled permanent-magnet synchronous motor drive are presented, showing the diagnostic algorithm effectiveness, its relatively fast detection time, and its robustness against false alarms.

A New Algorithm for Real-Time Multiple Open-Circuit Fault Diagnosis in Voltage-Fed PWM Motor Drives by the Reference Current Errors

Permanent magnet synchronous motor and power electronics-based three-phase inverter are the major components in the modern industrial electric drive system, such as electrical actuators in an all-electric subsea Christmas tree. Inverters are the weakest components in the drive system, and power switches are the most vulnerable components in inverters. Fault detection and diagnosis of inverters are extremely necessary for improving drive system reliability. Motivated by solving the uncertainty problem in fault diagnosis of inverters, which is caused by various reasons, such as bias and noise of sensors, this paper proposes a Bayesian network-based data-driven fault diagnosis methodology of three-phase inverters. Two output line-to-line voltages for different fault modes are measured, the signal features are extracted using fast Fourier transform, the dimensions of samples are reduced using principal component analysis, and the faults are detected and diagnosed using Bayesian networks. Simulated and experimental data are used to train the fault diagnosis model, as well as validate the proposed fault diagnosis methodology.

A Data-Driven Fault Diagnosis Methodology in Three-Phase Inverters for PMSM Drive Systems

Dissolved gas analysis (DGA) is used to assess the condition of power transformers. It uses the concentrations of various gases dissolved in the transformer oil due to decomposition of the oil and paper insulation. DGA has gained worldwide acceptance as a method for the detection of incipient faults in transformers.

A review of dissolved gas analysis measurement and interpretation techniques

Power transformer fault diagnosis based on dissolved gas analysis by support vector machine

This paper deals with multiple insulated gate bipolar transistor (IGBTs) open circuit faults detection and localization in a pulse width modulation (PWM) voltage source inverter (VSI) fed induction motor based on a modified slope method Firstly, a detection algorithm was used to calculate the slope of the current-vector trajectory in complex plan αβ This algorithm detects the faulty bridge Second, the Schmitt-trigger is used for the phase's currents monitoring This circuit determines the phase's currents polarity and detect whether the current in the faulty arm is positive or negative The analysis of two combined information makes it possible to diagnose the two simultaneous IGBTs open circuit fault within inverter The proposed technique is developed and implemented to vector control induction motor drives An experimental setup in the laboratory is used to compare the simulation results and the experimental results and to evaluate the performances of the proposed method

Multiple IGBTs open circuit faults diagnosis in voltage source inverter fed induction motor using modified slope method

This paper aims to provide a high-performance sensorless control of interior permanent magnet synchronous motor (IPMSM) based on nonlinear position and speed observer The proposed nonlinear observer is constructed using the flux linkage as new state variable without speed dependence The nonlinear observer gives estimation of the rotor position using a trigonometric function and the speed estimation is obtained from estimated position using proportional-integral (PI) tracking controller This observer is stable easy to implement and does not require a large computing time At standstill, we used the voltage pulses method to detect the initial rotor position Short voltage pulses are applied to the stator winding and the initial rotor position is estimated from the measured peak current High-dynamic performance is obtained using the vector field-oriented control and the space vector pulsewidth modulation techniques Experimental results with 11-kW IPMSM have validated the effectiveness of the proposed sensorless speed control using nonlinear observer The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the DSP TMS320F240

A Nonlinear Observer for High-Performance Sensorless Speed Control of IPMSM Drive

The industrial requirements for the control of an induction machine without a mechanical sensor continue to be of interest, as evidenced by the most recent publications. The focus is on improvements of control without a mechanical sensor. A new method for the implementation of a sensorless indirect stator-flux-oriented control (ISFOC) of a single-phase induction motor (SPIM) drive is proposed in this paper. The proposed method of rotor speed estimation is based only on the measurement of the main and auxiliary windings stator currents and that of a reference q-axis current generated by the control algorithm. The error of the measured q-axis current from its reference value feeds the proportional plus integral controller, the output of which is the estimated slip angular frequency. Experimental results for sensorless ISFOC speed control of a SPIM drive are presented and analyzed using a dSPACE system with DS1104 controller board based on the digital signal processor TMS320F240. Digital simulation and experimental results are presented to show the improvement in performance of the proposed sensorless algorithm.

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Moncef Gossa

Papers

Power transformer fault diagnosis based on dissolved gas analysis by support vector machine

Multiple IGBTs open circuit faults diagnosis in voltage source inverter fed induction motor using modified slope method

A Nonlinear Observer for High-Performance Sensorless Speed Control of IPMSM Drive

Sensorless Indirect Stator Field Orientation Speed Control for Single-Phase Induction Motor Drive

Induction machine fault detection using stray flux EMF measurement and neural network-based decision