Phase Open-circuit Fault Research Articles

A Novel Fault Tolerance Structure of Arc Linear Flux Switching Permanent Magnet Motors Based on Redundant Winding

This paper presents a novel structure of the arc linear flux switching permanent magnet motor based on the redundant winding to inhibit the rises of the motor losses and temperature due to the open circuit fault tolerance. Firstly, the structural characteristic of the arc linear flux switching permanent magnet motor is introduced. Then, the fault tolerance current of single phase open circuit fault is calculated for different winding connection forms. The fault tolerance performances under different conditions are compared from a special view of motor temperature rises. Finally, a novel structure for fault tolerance enhancement is proposed, which can effectively improve the freedom degree of the fault tolerance current by using the redundant winding. This novel structure takes full advantage of the circumferential air gap between the arc stator. The calculation results show that the novel structure can allow the fault tolerance of open circuit fault has little influence on the motor copper losses and temperature rises while maintaining the on-load torque.

High-Frequency Square-Wave Signal Injection Based Sensorless Fault Tolerant Control for Aerospace FTPMSM System in Fault Condition

To enhance position detection reliability, this article proposes a new high-frequency square-wave signal injection (HFSWSI) based sensorless control for aerospace fault tolerant permanent magnet synchronous motor (FTPMSM) drives, which can be configured as the nonsimilar redundancy for a physical sensor. The novel sensorless control scheme with HFSWSI in two nonfault windings is first proposed for the FTPMSM system under each phase current independent control frame, which is free of the coordinate transformation. The HFSWSI-based position detection is then proposed for rotor position estimation via HF response currents even in phase open-circuit fault (OCF) and short-circuit fault (SCF) conditions. To enhance the dynamic performance, a novel dual-output filter is proposed for the fundamental and HF response current component extractions with almost no phase lag. To guarantee the fault tolerant performance, the optimal torque control (OTC) is utilized to ensure that the FTPMSM system generates the ripple-free torque even in fault condition. The resulting sensorless FTPMSM system has outstanding low-speed sensorless control performance both in normal and fault conditions, which is also experimentally validated on a six-phase FTPMSM platform.

Remedy Strategy for Five-Phase FTPMMs Under Single-Phase Short-Circuit Fault by Injecting Harmonic Currents From Third Space

This article proposes a new fault-tolerant control for five-phase fault-tolerant permanent-magnet motors under single-phase short-circuit fault. In the proposed method, the effect on torque performance caused by a short-circuit fault is attributed into two parts: the loss of the short-circuited phase, which is equivalent to a phase open-circuit fault, and the resultant short-circuit current. The remedial action for loss of a phase is realized in the fundamental space, while the torque ripple caused by the short-circuit current is compensated by the harmonic currents in the third space. To decouple the control of the fundamental and third space, the reduced-order Clarke and Park transformation matrixes for the two spaces are obtained separately under single-phase short-circuit fault. Afterward, the fundamental currents with minimum joule losses or equal joule losses for loss of a phase, and the harmonic currents in the third space for torque ripple reduction are derived. Hence, the proposed method can realize torque ripple-free operation under single-phase short-circuit fault. Finally, the effectiveness of the proposed method is verified by experimental results under various operational conditions.

A differential operation principle of the automatic bus transfer system pickup unit as a way of decreasing the emergency clearing time.a

A proper choice of the design and operation algorithm of emergency control devices like high-speed bus transfer (HSBT) is only possible proceeding from a study and analysis of steady-state and transient processes in emergency modes of operation (short-circuit faults, power supply disconnection, or phase open-circuit fault). The numerical experiments for studying such modes that were carried out, using the Matlab Simulink software package, on the mathematical models of an industrial power supply system involving synchronous motors connected to it made it possible to synthesize a new differential HSBT pickup unit featuring a high-speed response to emergency events. In doing so, special attention was paid to an analysis of transient operation modes with the aim of minimizing the probability of false actuations. The obtained study results have found practical application in the HSBT devices installed at the facilities of PJSC MOSENERGO. The experience gained from the operation of a new device jointly with high-speed circuit breakers produced by the Tavrida-Elektrik state-owned corporation has demonstrated essential advantages in comparison with the conventional HSBT designs.

Guaranteeing the fault transient performance of aerospace multiphase permanent magnet motor system: An adaptive robust speed control approach

To enhance the fault transient performance of aerospace multiphase permanent magnet synchronous motor (PMSM) system, an adaptive robust speed control is proposed regardless of the phase open-circuit (OC) and short-circuit (SC) fault in this paper, which can be applied for both the redundant motor system and fault tolerant motor system. For aerospace multiphase PMSM system, besides external load disturbance and system parameter perturbation, there inevitably exists the electromagnetic torque ripple in fault transient process, which can degrade the system performance and even cause the system instability. To cope with this issue, the electromagnet torque ripple of the multiphase PMSM system in fault transient process is first analyzed. Then, by considering the electromagnet torque fluctuation caused by fault transient as a system uncertainty, a novel adaptive robust speed control scheme is proposed, while the adaptive law is constructed to emulate the total system uncertainty bound, which include the load disturbance, the parameter variation, and the electromagnetic torque fluctuation due to fault transient. The resulting control can ensure the speed control performance even in fault transient process regardless of the uncertainty, in which no prior estimation of the uncertainty bound is required. In addition, the proposed adaptive robust speed control is demonstrated by a six-phase PMSM experimental platform. The novelty of this research is to explore a novel adaptive robust speed control to strengthen the fault tolerance performance of multiphase PMSM system even in fault transient process, which requires no prior estimation of the uncertainty bound.

Realization of fault tolerant capability in a multiphase SRM drive using wavelet transform

Switched Reluctance Motor (SRM) are widely used in drives market because of its elegant features such as simple arrangement, manufacturing cost, minimal maintenance and wide speed range. Significant investigation has been conducted to lengthen the feasibility of SRM drive technologies in various aspects such as control strategy, torque ripple minimization, an optimal winding arrangement, etc. Even though it has numerous virtues, there are few noticeable issues that occur in SRM. In this paper, the issues like phase open circuit fault, phase-phase short circuit fault, power switch failure, dc link capacitor failure, and encoder faults are discussed using Wavelet Transform (WT) with their experimental results. A multi-phase (10/8 pole) SRM motor is considered to investigate the fault tolerance proficiency and other performance parameters. Initially, a healthy condition of multi-phase SRM is simulated then faults are injected at different phases which are analyzed and validated using MATLAB simulink tool and the same is validated through experimental results. The performance parameters of SRM drive during various faults conditions are analyzed and the impacts of speed and torque are illustrated.

Sensorless Fault-Tolerant Control With Phase Delay Compensation for Aerospace FTPMSM Drives With Phase Open-Circuit and Short-Circuit Faults

To enhance the reliability of fault-tolerant permanent-magnet synchronous motor (FTPMSM) drives, a new sensorless control based on the robust observer, nonorthogonal phase-locked loop (PLL), and variable phase delay compensation is proposed, which can guarantee the medium- and high-speed sensorless control performance for the FTPMSM even in the phase open-circuit and short-circuit fault conditions. A robust observer is proposed to achieve any two healthy phase back electromotive force (EMF) estimation, regardless of the parameter variation, external disturbance, and the phase fault. The nonorthogonal PLL is presented to extract the information of the rotor position from the observed two nonorthogonal phase back-EMFs. To enhance the estimation accuracy of the rotor position as the speed changes, the variable cut-off frequency low-pass filter (VLPF) is proposed to eliminate the high-frequency noises of the observed phase back-EMFs, while a phase delay compensation is presented to compensate for the estimation deviation caused by the VLPF. The resulting sensorless FTPMSM system has excellent speed control performance both in normal and fault conditions, which is also demonstrated by a six-phase FTPMSM system experimental platform.

Bidirectional multiport solar‐assisted SRM drive for pure electric vehicle applications with versatile driving and autonomous charging capabilities

Pure electric vehicles (PEVs) offer a solution for achieving a zero-emission transport system. This study presents the work towards the development of a bi-directional multiport solar-assisted switched reluctance motor (SRM) drive for PEV applications having battery-to-vehicle (B2V), photovoltaic (PV)-to-vehicle (PV2V), PV assisted B2V, grid-to-vehicle battery charging and PV2V battery charging functions. The power circuit is formed by the combination of a front-end circuit and a modified-Miller SRM converter. Battery, PV panel, grid and SRM form the four ports of this multiport drive, which with proper control, provide motoring, braking and charging functions. The dc-link voltage is fully controllable which improves the machine performance both at higher and lower speeds. During stand-still conditions, the battery is charged either from the grid at unity power factor or through the PV panel by incorporating the drive components to form an on-board battery charger, thereby reducing the reliance on charging stations. A fault-tolerant control is developed to operate the system with desired performance under single and double phase open-circuit faults. An 8/6 SRM is used for proof of concept and the experimental results confirm the effectiveness of the proposed drive and control strategy.

Fault-tolerant control of Y-connected three-phase induction motor drives without speed measurement

Fault-Tolerant Control (FTC) in adjustable speed drives under open-circuit faults has been broadly investigated in the literature. Nevertheless, studies in this area have been normally focused on sensored machine drives. This research focuses on the FTC approach for Y-connected Three-Phase Induction Motor (TPIM) drives without speed measurement. An Extended Kalman Filter (EKF) and a Rotor Field Oriented Control (RFOC) system are developed in order to control sensorless speed controlled Y-connected TPIM during both healthy and Single Phase Open-Circuit Fault (SPOCF) conditions. Unlike the conventional sensorless control system, the proposed drive system can be used for the sensorless speed controlled Y-connected TPIM during both normal and SPOCF conditions. The performances of the proposed FTC scheme are implemented on a DSP/TMS320F28335 controller board for a 0.75 kW Y-connected TPIM drive system. Different experimental results are shown to verify the effectiveness and possibility of the introduced technique.

Performance assessment of triple redundant nine‐phase delta‐ and wye‐connected permanent magnet‐assisted synchronous reluctance motor under healthy and fault conditions

In this study, the performance of a triple redundant nine-phase permanent magnet-assisted synchronous reluctance motor with delta-connected windings is comprehensively assessed and compared with that of wye-connected winding under healthy and fault conditions, including open circuit, inter-turn short-circuit and terminal short circuit. The steady-state torque behaviour, loss, efficiency and temperature distribution of the two winding configurations are analysed and compared. It is shown that the delta-connected winding has higher output torque under one phase open-circuit fault and lower inter-turn short-circuit current with three-phase terminal short circuit.

A Permanent Magnet Assist, Segmented Rotor, Switched Reluctance Drive for Fault Tolerant Aerospace Applications

This paper presents the design, analysis, prototype, and testing of a new fault tolerant electrical drive topology. The segmented rotor switched reluctance machine (S-SRM) has been modified to include permanent magnet assist by placing magnets in the stator slot opening. This introduces a magnetic bias which extends the magnetic operating region of the machine and results in greater torque when compared to the conventional fault tolerant segmental rotor switched reluctance machine. This new torque dense, fault tolerant topology was investigated using 2-D (two-dimensional) and 3-DFE methods and a prototype machine built, tested and verified against the simulations. Experimental testing was carried out with and without the magnets to assess the effect of the PM assist on torque performance. Static tests were carried out to obtain the torque—flux linkage—angle waveforms and then this information used to tune a bespoke drive and test the system under dynamic conditions. The superior fault tolerant performance of this PMA S-SRM topology is highlighted by measurements taken under phase open and short circuit fault conditions. The tests show that this fault-tolerant topology not only meets the mass requirements of the aerospace application, set originally by a PMSM, but also, with the magnets now placed on the stator the rotational induced EMFs and associated short circuit currents during a fault are drastically reduced. Hence the fault tolerance of this topology is an improvement on the PMSM topology, and it will be of benefit to fault critical systems such as aerospace drives and actuators.

Реализация защит от аварийных режимов в электроприводе вентиляторов малой мощности

The paper deals with the design of an inverter supplying power to the drive of fans cooling the subway car brake resistors and the traction electric drive power converter’s heat sink fins. Since this fan drive is a low-capacity one, it was decided to make the inverter for it with the minimal possible cost. To achieve the desired objective, it was decided to exclude protections from certain very unlikely emergency modes. It was proposed to use cheap IC chips of transistor switch drivers and to implement short-circuit protection using current transformers. The current transformers have a very large bandwidth and can be used in the application in question not only to protect the motor, but also to protect the inverter transistor switches. The current transformer signals are rectified by a low-capacity rectifier, thus making it possible to eliminate separate processing of the phase current positive and negative half-waves. The rectified signals are fed to the input of the protection circuit implemented on operational amplifiers. The total time of short-circuit protection system response to the input signal is about 1 μs. In measuring the current transformers’ output signals, it is possible to obtain a sufficient amount of data for making overload protection, phase open-circuit fault protection, load imbalance protection, and thermal protection. Emergency modes detection algorithms for implementing them in the scope of the electric drive microprocessor control system are presented. The proposed solutions were investigated on a mathematical model and on the inverter mockup prototype, and the obtained results have demonstrated their efficiency. &nbsp

Sensorless Control of a Fault-Tolerant Multi-Level PMSM Drive

This paper presents a new technique to track the saliency position in a permanent magnet synchronous motor (PMSM) post a single phase open-circuit fault. The PMSM is driven by a fault-tolerant multi-level inverter that is utilized to implement a fault-tolerant control strategy to minimize system performance degradation post the fault.The fault-tolerant multi-level inverter is consisting of a number of insulated-gate bipolar transistors (IGBTs). The dynamic current reponses of the PMSM motor due to the switching actions of these IGBTs are used extract the saliency position. This process is not introducing any modification to the operation of the fault-tolerant multil-level inverter as it uses only the fundamental pulse width modulation (PWM) waveform. Moreover,it considers the modifications introduced to the PMSM motor and the multi-level inverter post the fault.Simulation results are provided to verify the effectiveness of the proposed strategy of saliency tracking of a PMSM motor driven by a fault-tolerant four-leg multi-level inverter over a wide range of speeds in the case of a single-phase open circuit fault.

Fault‐tolerant electric drive and space‐phasor modulation of flux‐switching permanent magnet machine for aerospace application

This study investigates how to improve the fault tolerance or availability of an electrical drive containing a three-phase 12 stator teeth/10 rotor poles (12/10) the flux-switching permanent magnet machine. In this respect, space-vector modulation and space-phasor modulation will be analysed in this type of machine for control scheme design under three-phase operation. While for safety critical applications, availability requires that during faults, such as loss of one inverter phase leg or open circuit of one machine phase winding, the electrical drive system remains partly operational. Therefore, initial research is given in this study on the implementation of control algorithms that drives the machine under normal condition and preserves the electromagnetic torque under phase open-circuit faults.

Sensorless Control of a Fault Tolerant PMSM Drives in Case of Single-phase Open Circuit Fault

This paper introduces a sensorless-speed-controlled PMSM motor fed by a four-leg inverter in case of a single phase open circuit fault regardless in which phase is the fault. To minimize the system performance degradation due to a single phase open circuit fault, a fault tolerant control strategy that includes taking appropriate actions to control the two remaining healthy currents is used in addition to use the fourth leg of the inverter. Tracking the saliency is done through measuring the dynamic current responses of the healthy phases of the PMSM motor due the IGBT switching actions using the fundamental PWM method without introducing any modification to the operation of the fourth leg of the inverter. Simulation results are provided to verify the effectiveness of the proposed strategy for sensorless controlling of a PMSM motor driven by a fault-tolerant four-phase inverter over a wide speed ranges under the case of a single phase open circuit.

Wavelet Transform Based Fault Diagnosis of BLDC Motor Drive

Due to the development in science and technology tremendous improvement in solid state devices and circuits, so we need to reduce the complexity of control circuits. The Brushless DC Motor (BLDCM) has simple construction, stator consists of winding and rotor consists of permanent magnet. It has higher efficiency and high speed range. In this paper presents the vibration analysis of single phase open circuit fault conditions and the signals are extracted from the Discrete Wavelet Transform (DWT). The Spartan-6 FPGA processor was implemented due to their high performance of the control applications in recent decades. In this process Sinusoidal Pulse Width Modulation (SPWM) techniques were used to control the speed of BLDC Motor. The experimental analysis is carried out in 3phase, BLDCM drive. The vibration signals are measured by using Accelerometer through Lab VIEW software. DOI: http://dx.doi.org/10.11591/telkomnika.v14i3.7967

Phase Open Fault Tolerant Control of High Reliability Doubly-Salient Wound-Field Machine

Doubly Salient Wound-Field Machine (DSWFM) can be employed on aeronautics starter-generator because it has good performance on both power generation and starting. To improve the system reliability, a three-phase four bridge legs converter which has fault tolerant capability is proposed to solve one phase open-circuit fault problem of the DSWFM. And the advantage of the proposed converter to the full-bridge converter fault-tolerant mode is analyzed. With the study of DSWFM theory and torque equation, a constant torque fault-tolerant strategy is proposed to keep the performance and reduce the torque ripple. The drive system after fault identification can be reconstructed by the proposed method, and the machine performance can recover quickly. Simulations confirm the feasibility of the proposed fault tolerant system.

DTC of Three-Phase PM BLAC Motor Having One Phase Open-Circuit Fault with Current Model Flux Estimator

Direct torque control (DTC) of three-phase permanent magnet brushless AC (PM BLAC) motor having one phase open-circuit fault (OPOF) is presented. Torque and flux linkages of the faulty motor are estimated by proposed estimators. Control topology, voltage vectors and design procedure are described. Simulated results show that the proposed topology can be operated under fault situation at rated torque and speed operation. Performances of the system are validated by the measured data.

Direct Slip Linear Control of Three-Phase Induction Motor with One Phase Open-Circuit Fault Based on Three-Level Inverter

In order to realize high power and reliability of speed control system, fault-tolerant induction motor control system based on three-level inverter is studied in this paper. Based on three-level inverter, a fault-tolerant inverter topology with an extra leg providing the current path during the post-fault operation is proposed. A corresponding control strategy is investigated to avoid voltage drift of the dc link midpoint. In this paper, an induction motor direct slip linear control (DSLC) is employed and investigated to reduce torque ripple and flux magnitude deviation in three-level system. Both simulation and experimental system have been set up to verify the effectiveness of the proposed control strategy.

Rotor losses in fault-tolerant permanent magnet synchronous machines

The necessary reliability of safety-critical aerospace drive systems is often partly achieved by using fault-tolerant (FT) electrical machines. There are numerous published literatures on the design of FT machines as well as on control algorithms used to maintain drive operation with an incurred fault. This study is set to look at the rotor losses in three- and five-phase surface mount permanent magnet machines when operating in faulty mode in order to highlight the influence of the post-fault control strategy and winding configuration. Although the work presented in this study is mainly focused on FT control methodologies targeted at mitigating phase open circuit faults, the implications of short-circuit faults is also considered and discussed.