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The purpose of this study is to propose an extended reliability method for an industrial motor drive by integrating the physics of failure (PoF).

Industrial motor drive systems (IMDS) are currently expected to perform beyond the desired operating conditions to meet the demand. The PoF of the subsystem affects its reliability under such harsh operating circumstances. It is crucial to estimate reliability by integrating PoF, which helps in understanding its impact and to develop a fault-tolerant design, particularly in such an integrated drive system. An integrated PoF extended reliability method for industrial drive system is proposed to address this issue. In research, the numerical failure rate of each component of industrial drive is obtained first with the help of the MIL-HDBK-217 military handbook. Furthermore, the mathematically deduced proposed approach is modeled in the GoldSim Monte Carlo reliability workbench.

From the results, for a 15% rise in integrated PoF, the reliability and availability of the entire IMDS dropped by 23%, resulting in an impact on mean time to failure (MTTF).

The integrated PoF of the motor and motor controller affects industrial drive reliability, which falls to 0.18 with the least MTTF (2.27 years); whose overall reliability of industrial drive drops to 0.06 if it is additionally integrated with communication protocol.

This study aims to develop a finite element method based co-simulation platform for the numerical analysis of motor drive system. With the rising requirement of industry, the comprehensive design of motor drive systems has attracted increasing attentions. An accurate model, which considers the coupling between motor and its drive system, is vital for the analysis and design of motor drive system.

Considering the coupling relationship between motor and its drive system, a flexible and extensible co-simulation platform of motor drive system is developed with the C++ language and finite element machine model to carry out the comprehensive analysis of motor drive system. The control system simulation program developed with C++ language adopts the same discrete form as the single-chip microcomputer and can simulate the interrupt mechanism, making the simulation closer to the actual control system. With the finite element analysis results of current step, the winding input voltage of next step is calculated by the executable program of control system and is fed into the finite element analysis, forming the two-way coupling analysis of drive system.

Preliminary studies, such as calculation of machine core losses fed by inverters, and control parameters optimization, are conducted with this platform, which shows the flexibility and expansibility of this platform.

The power inverter circuit along with the controller is modeled using the C++ language, and embedded into the finite element machine model to achieve more realistic motor drive system simulation and complex functions.

This paper seeks to present a fully digital, real‐time (RT) hardware‐in‐the‐loop (HIL) simulator on PC‐cluster, of electric systems and drives for research and education purposes; to use the developed system to conduct several motor drives implementation and to evaluate the motor and the control algorithm performance in RT.

This simulator was developed with the aim of meeting the simulation needs of electromechanical drives and power electronics systems while solving the limitations of traditional RT simulators. This simulator has two main subsystems, software and hardware. The two subsystems were coordinated together to achieve the RT simulation. The software subsystem includes MATLAB/Simulink environment, a C++ compiler and RT shell. The hardware subsystem includes FPGA data acquisition card, the control board, the sensors, and the controlled motor.

The complexity of RT implementation of motor drives is greatly reduced by utilizing this simulator. The detailed operation and implementation of this simulator are presented, together with test results and comparisons with simulated virtual environment for a permanent magnet dc and induction motors (IM). The simulator performance is adequate for both open and closed loops motor drives. The simulation time step is limited by the system Master/Target CPU's speed, the communication network type, and the complexity of the control algorithm.

A typical application for this system is to select and evaluate the performance of electric motors for a hybrid electric vehicle in a real vehicle environment without actually installing that component in the real vehicle.

The use of the developed RT simulator to achieve HIL simulation allows rapid prototyping, converter‐inverter topologies testing, motors testing, and control strategies evaluation. The transition from simulated virtual environment to the HIL mode can be performed by replacing the model of the physical system (e.g. motor) with the DAQ blocks to represent the channels connected to the physical system sensors. The use of a single environment for both simulation and HIL control provides a quick experimentation and performance comparison between the real and simulated systems.

The study aims to show the influence of selected mechanical parameters of the rotor on the maximum speed and parameters of the electric motor.

A simplified mechanical analysis of the rotor of the electric motor was conducted, determining the safety factor of the motor. An analysis of the impact of key rotor parameters (significant from the mechanical strength perspective) on the electromagnetic parameters and the safety factor of the selected high-speed electric motor was carried out. The influence of changes in the rotor’s geometrical dimensions (centrifugal force) on the electromagnetic parameters of the electric motor was shown.

The study shows the impact of changes in selected rotor parameters on electromagnetic parameters and the safety factor of a high-speed electric motor (at its required operating point of 45,000 rpm). The dependence of the safety factor as a function of the maximum motor speed was determined for the proposed rotor modifications.

The proposed modifications can be used in larger drive systems. They have practically no impact on increasing the value of the motor’s moment of inertia (they do not degrade the dynamics of the motor’s operation).

It was proposed to use a new design coefficient which is in relation to the motor’s safety coefficient. It has been shown that a minimal modification of the motor rotor allows to increase its maximum speed by several dozen per cent (while maintaining the safety factor). It has also been shown that when operating at maximum speed within the safe range, the change in the geometrical dimensions of the rotor hardly influences the change in the value of the centrifugal force.

The purpose of this paper is to propose an analytical method for prediction of self‐sustained oscillations that might happen during low‐cost induction motor drive application. This forecast is needed to avoid unwanted oscillations that can be encountered for in fan, compressor and pump drives utilizing open‐loop frequency‐controlled three‐phase induction motor drives.

The paper presents the model of the induction motor drive system that includes inverter switches dead‐time and allows discontinuous current of front‐end rectifier. Stability analysis of proposed model was performed by tracing the eigenvalues of the overall system matrix.

Discontinuous rectifier current at light loads and the dead‐time of the inverter switches are the main sources of undesired low‐frequency self‐sustained speed oscillations in open‐loop controlled induction motor drives. The evaluated risk prediction is a function of drive and motor parameters and load level.

The proposed induction motor drive system model highlights the direct connection between the self‐sustained speed oscillations and the system parameters like inverter dead time, dc capacitor values, motor parameters and motor load level. Good accuracy of instability prediction is verified by dynamic simulation and by extensive experimentation.

The aim of this paper is to undertake analysis and comparison of the closed‐loop and sensorless control systems sensitivity to the broken rotor for diagnostic purposes. For the same vector control system induction motor drive analysis concerning operation with the asymmetric motor, broken rotor fault handling and operation were investigated. Reliability, range of stable operation, fault symptoms and application of diagnosis methods based on control system variables utilization was analyzed.

Induction motor drive vector control system synthesis was applied using the multiscalar variables of the machine model with nonlinear feedback linearization applied to use classical cascaded PI controllers for the speed‐torque and flux decoupled control. Speed observer was applied for the rotor flux and rotor speed estimation for the sensorless control system synthesis.

Relative sensitivity of the state and control system variables to broken rotor fault based on experimental results for the closed‐loop and sensorless control systems is presented and compared. Drawbacks of using the MCSA analysis for the rotor fault diagnosis in the closed‐loop and sensorless control systems are pointed. Advantages and drawbacks of the state space estimators filtering characteristics in the sensorless control system are described.

Asymmetric IM motor drive handling and diagnosis. Broken rotor range diagnosis inconsistency using the popular MCSA method should be considered in the closed‐loop and sensorless control system of the induction motor drive. Depending on the IM motor drive application and the operation requirements the results can be used for asymmetric machine proper handling, choosing proper control system structure and control system variables for rotor fault early diagnosis.

Sensitivity of the state and control system variables to broken rotor fault based on experimental results for the closed‐loop and sensorless control systems is presented, which implies motor handling procedures and fault diagnosis.

The purpose of this paper is to present a fixed‐point implementation of a complete direct torque control (DTC) algorithm connected with a rotor speed estimation algorithm for the induction motor drive, using field‐programmable gate array (FPGA).

The parallel processing approach is described, which requires a decomposition of the control and estimation algorithms for the converter‐fed induction motor to several tasks, realised in parallel. The advanced data processing techniques are described, like PIPELINE technique for data streams design, coordinate rotation digital computer algorithm for transformation of stator flux vector components from Cartesian to polar coordinates. Moreover, the method for the qualitative analysis of the full‐order state observer's sensitivity to the variations of the induction motor equivalent circuit parameters is presented.

It is shown that the developed FPGA‐based DTC structure enables designing an efficient application for the induction motor control. Owing to the high‐processing frequency, the digital FPGA‐based DTC application is similar in its features to the analogue realisation based on the comparators. Yet all the advantages of the digital structure, i.e. high flexibility, parameterization capability, etc. remain unchanged. Furthermore, FPGA is hardware realisation of a digital data processing algorithm; hence the reliability of the control system is improved.

The investigations are performed in the developing prototype setup, based on PXI‐1042 Industrial PC equipped with Xilinx Virtex‐II FPGA matrix, programmed with LabVIEW.

The experimental tests of the FPGA‐based implementation of the whole control structure of the sensorless DTC drive system are demonstrated. It is also shown, that the full‐order state observer with the speed adaptation loop is significantly sensitive to motor parameter variations in the low‐speed region, which must be taken into account while designing the adaptation algorithm for speed estimation in real application.

The paper's value lies in the overall, FPGA‐based design of the speed sensorless DTC structure for the induction motor including motor speed, torque and stator flux control loops, stator flux and rotor speed estimation.

The purpose of this paper is to develop an electronic solution to effectively lock swivelling wheel steering positions to driver‐control. Simple and affordable systems are described to assist forklift users in steering their walkie type forklifts or pallet jacks across sloping ground.

A rolling road was created as an assessment tool and trials with both the test bed and in real situations were conducted to evaluate the new systems. The small swivel detector that was created could be successfully attached to swivelling wheel swivel bearings.

The new system was successful, robust and was not affected by changeable parameters. The simple systems assisted hand truck operators in steering their forklifts across sloping ground without veering off course. The systems overcame the problems associated with forklifts that steer using two swivelling wheels and meant that less work was required from hand truck operators as their forklifts tended to travel in the desired direction

Experiments demonstrated that calibrating forklift controllers for straight‐line balance and optimizing motor‐compensation did not solve this problem. Instead, swivelling wheel angle was selected to provide feedback. At the point when veer is first detected, a forklift has already begun to alter course and the job of the correction system is to minimize this drift from the desired course.

The forklifts and pallet jacks often steer by having swivelling wheels but problems with this configuration occur when a forklift is driven along sloping ground because they can swivel in the direction of the slope. Gravity then causes the forklift or pallet jack to start an unwanted turn or “veer” and the vehicle goes in an unintended direction. This situation is exacerbated for vehicles with switch controls, as switches cannot provide fine control to trim and compensate.

Each year in the United States, over 100 employees are killed and 36,000 are seriously injured in accidents involving forklift trucks and pallet carriers. This is the second leading cause of occupational fatalities in “industrial” type workplaces. The research aims to make the use of this type of equipment safer and the systems can be attached to many standard forklifts and pallet jacks.

This paper aims to propose a novel system identification and resonance suppression strategy for motor-driven system with high-order flexible manipulator.

In this paper, first, a unified mathematical model is proposed to describe both the flexible joints and the flexible link system. Then to suppress the resonance brought by the system flexibility, a model based high-order notch filter controller is proposed. To get the true value of the parameters of the high-order flexible manipulator system, a fuzzy-Kalman filter-based two-step system identification algorithm is proposed.

Compared to the traditional system identification algorithm, the proposed two-step system identification algorithm can accurately identify the unknown parameters of the high order flexible manipulator system with high dynamic response. The performance of the two-step system identification algorithm and the model-based high-order notch filter is verified via simulation and experimental results.

The proposed system identification method can identify the system parameters with both high accuracy and high dynamic response. With the proposed system identification and model-based controller, the positioning accuracy of the flexible manipulator can be greatly improved.

Electric vehicles (EVs) require uninterrupted and safe conditions during operations. Therefore, the diagnostic of power devices and electric motor faults are needed to improve the availability of the system. Hence, fault-tolerant control (FTC), which combines switch fault detection, hardware redundancy and post-fault control, is used. This paper aims to propose an accurate open-phase fault detection and FTC of a direct torque control permanent magnet synchronous motor electrical vehicles by using discrete Fourier-transform phase method.

The main idea is to propose detection and identification of open-phase fault (faulty leg) among three phases voltage source invertor (VSI)-fed permanent magnet synchronous motor drives. Once the faulty leg is detected and isolated, a redundant phase leg insertion, shared by a three-phase VSI, is done by using independent bidirectional TRIAC switches to conduct FTC system. This accurate fault detection significantly improves system availability and reliability. The proposed method of open-phase fault detection and identification is based only on stator phase current measurement.

A novel method is proposed with experimental validation for fault detection, isolation and FTC for a three-phase VSI-fed permanent magnet synchronous motor.

The novel discrete Fourier-transform phase method is proposed to detect an open phase based on the measurement in real time of the instantaneous phase of stator current components in the stationary frame. The experimental implementation is carried out on powerful dSpace DS1104 controller board based on the digital signal processor TMS320F240. The validity of the proposed method has been experimentally verified.