Five-phase Permanent Magnet Synchronous Motor Research Articles

Cascade Model Predictive Current Control for Five-Phase Permanent Magnet Synchronous Motor

As to the model predictive control for five-phase permanent magnet synchronous motor (PMSM), it is difficult to ensure the optimal control performance by using calculation method to obtain the weighting factor. To solve this problem, a cascade model predictive current control based on the idea of sequential model predictive control is proposed for five-phase PMSM for the first time. Firstly, the principle of selecting the optimal voltage vector by the proposed method is analyzed in detail. Then, combined with the characteristics of five-phase PMSM, the control priority of controlled variables is set for designing two cost function schemes without weight factor. The maximum torque scheme can generate a trapezoidal stator voltage, improving the DC bus voltage utilization rate and the system loading capacity. The minimum harmonic current scheme can reduce the harmonic of stator current, obtaining small system noise and vibration. The experimental results indicate that the proposed method can ensure the optimality of the voltage vector applied. Therefore, the five-phase PMSM obtains good performance under different working operation, such as small torque ripple, fast dynamic response, and small harmonic current.

Speed sensorless FCS-MPTC based on FOSM-MRAS five-phase permanent magnet synchronous motor

Speed sensorless FCS-MPTC based on FOSM-MRAS five-phase permanent magnet synchronous motor

Sliding-Mode-Based Current and Speed Sensors Fault Diagnosis for Five-Phase PMSM

The present paper deals with an active fault-tolerant speed tracking of a five-phase permanent magnet synchronous motor with currents and speed sensor failures. The active fault tolerant control scheme, integrating a sliding mode observer and backstepping controllers, is proposed to provide a continuous drive operation of the five-phase permanent magnet synchronous motor, even during more than one sensor fault occurrence. The sliding mode observer is designed to generate the residual signal necessary for the detection stage, whereas speed and current backstepping controllers handle the operation of the five-phase permanent magnet synchronous motor thanks to their ability to consider the nonlinearities of the system model in generating a control law that is robust enough in healthy and faulty cases. Furthermore, the FTC strategy uses the information received from the fault-tolerant switching block in terms of the measured and the observed currents and speed signals. To gain the maximum benefit of the sliding mode observer’s robustness to random noises and its ease of implementation, the observed currents and speed of the five-phase permanent magnet synchronous motor have been estimated. The simulation results are conducted to show the effectiveness of the proposed FTC control scheme and to prove its high performance in fault detection and tolerant control for the five-phase permanent magnet synchronous motor, since it significantly outperforms the performance provided by traditional methods.

Performance analysis and comparison of two fault-tolerant model predictive control methods for five-phase PMSM drives

Model predictive current control (MPCC) and model predictive torque control (MPTC) are two derivatives of model predictive control. These two control methods have demonstrated their strengths in the fault-tolerant control of multiphase motor drives. To explore the inherent link, the pros and cons of two strategies, the performance analysis and comparative investigation of MPCC and MPTC are conducted through a five-phase permanent magnet synchronous motor with open-phase fault. In MPCC, the currents of fundamental and harmonic subspaces are simultaneously employed and constrained for a combined regulation of the open-circuit fault drive. In MPTC, apart from the torque and the stator flux related to fundamental subspace, the x-y currents are also considered and predicted to achieve the control of harmonic subspace. The principles of two methods are demonstrated in detail and the link is explored in terms of the cost function. Besides, the performance by two methods is experimentally assessed in terms of steady-state, transition, and dynamic tests. Finally, the advantages and disadvantages of each method are concluded.

Model Predictive Torque Control of Five-Phase PMSM by Using Double Virtual Voltage Vectors Based on Geometric Principle

The conventional model predictive torque control (MPTC) suffers from the heavy computation burden and the uncertainty of the weighting factor. This article proposed a new MPTC scheme for a five-phase permanent magnet synchronous motor by using double virtual voltage vectors (VVVs), in which no weighting factor is required. The VVVs that can restrain the harmonics work as the candidate vectors. The deadbeat principle is adopted to predict the reference voltage, which can be used to select the optimal VVV directly in avoid of testing all candidate VVVs, and hence, the computation burden is reduced. The geometric principle is applied to select the second voltage vector and calculate the vector duration. The second vector can be a VVV or null vector. Therefore, double VVVs or a VVV and a null vector can be synthesized for the next period. It should be noted that no weighting factor is required because of the introduced geometric principle. Due to the selection of the second voltage vector, the torque and flux ripples are reduced and the steady-state performance is improved. The proposed MPTC has the same fast dynamic response with the conventional MPTC. The experiments are presented to verify the proposed MPTC scheme.

Finite‐control‐set model prediction current control of five‐phase permanent magnet synchronous motor based on eight‐switch fault‐tolerant inverter

The existence of unbalanced voltage and current harmonics is one of the most pressing issues when the failure happens on the inverter, which will render the inverter less reliable or even failed. Therefore, an improved finite-control-set model predictive current control (FCS-MPCC) is proposed for eight-switch fault-tolerant inverter (ESFTI)-driven five-phase permanent magnet synchronous motor (FPPMSM). First, the topological structure of the whole system and the mathematical model of FPPMSM are presented. Second, the unbalance voltage and the predictable current vector of the controlled system are analysed in terms of FCS-MPCC. After that, the information of the corresponding control voltage vector is obtained by utilizing the deadbeat current control, which realizes the partial vector enumeration in the ideal voltage vector plane. Furthermore, the concept of two-step forward prediction is integrated to induce the manipulated variables at next sampling time such that the time delay may be alleviated, whose corresponding minimum cost function is constructed by extra considering the fluctuation of the capacitor voltages. Finally, the comparative simulation studies between the traditional FCS-MPCC and the proposed one are carried out to demonstrate the validity and effectiveness of the proposed method.

Diagnosis of open-phase fault of five-phase permanent magnet synchronous motor by harmonic current analysis

A new fault diagnosis strategy is proposed for the single-phase (two-phase) open-circuit faults of the five-phase PMSM (FP-PMSM). Firstly, the output characteristics of the terminal voltage before and after the open-circuit fault are analyzed, and the expressions of the fundamental current in the α-β subspace under 15 fault states and normal states are obtained. The trajectory of the fundamental current in the α-β subspace is circular in the normal state and elliptic in the fault state. Therefore, the open-circuit fault determination is based on the distance from the current trajectory to the origin. Secondly, according to the output characteristics of the terminal voltage under different fault states, the trajectory distribution characteristics of the third harmonic current in the d-q subspace under 15 open-circuit fault states are obtained. By comparison, the trajectory distribution characteristics of different open-circuit faults are very different, which can be used as a basis for fault location. Finally, an experimental platform built with DSP as the core is used to verify the proposed fault diagnosis strategy. Experimental results show that the fault diagnosis strategy quickly determines and locates faults in steady-state and dynamic conditions.

Fault-tolerant deadbeat model predictive current control for a five-phase PMSM with improved SVPWM

The main drawbacks of traditional finite set model predictive control are high computational load, large torque ripple, and variable switching frequency. A less complex deadbeat (DB) model predictive current control (MPCC) with improved space vector pulse-width modulation (SVPWM) under a single-phase open-circuit fault is proposed. The proposed method predicts the reference voltage vector in the α-β subspace by employing the deadbeat control principle on the machine predictive model; thus, the exhaustive exploration procedure is avoided to relieve the computational load. To perform the constant switching frequency operation and achieve better steady-state performance, a modified SVPWM strategy is developed with the same conventional structure, which modulates the reference voltage vector. This new approach is based on a redesigned and adjusted post-fault virtual voltage vector space distribution that eliminates the y-axis harmonic components in the x-y subspace and ensures the generation of symmetrical PWM pulses. Meanwhile, the combined merits of the DB, MPCC, and SVPWM methods are realized. To verify the effectiveness of the proposed control scheme, comparative experiments are performed on a five-phase permanent magnet synchronous motor (PMSM) drive system.

A compare research on third harmonic current control for five-phase permanent magnet synchronous motor

The injection of a third harmonic current can improve the electromagnetic torque output of the five-phase permanent magnet synchronous motor. In this paper, constant copper consumption and constant maximum current are used as constraints, and the influence of the ratio between the third harmonic current and the fundamental current on the electromagnetic torque under the two constraints is analyzed. The electromagnetic torque is the largest when the third harmonic current reference value is equal to the fundamental current reference value of ψf3/ψf times under the premise of the constant copper loss. On the premise that the maximum current is constant, the electromagnetic torque is the largest when the third harmonic current reference value is equal to the fundamental current reference value of kw/(6kw-kw3/3) times. On this basis, according to the vector amplitude, phase and action time, the changing trends of maximum voltage utilization rate with Vref3/Vref1 under three different kinds of methods are given. Finally, through the experimental platform, the control effects of the three kinds of SVPWM are compared under two constraint conditions.

Feedforward Neural Network-DTC of Multi-phase Permanent Magnet Synchronous Motor Using Five-Phase Neural Space Vector Pulse Width Modulation Strategy

In this work, the direct torque control (DTC) is applied to the five-phase permanent magnet synchronous motor (FP-PMSM). The DTC method based on classical space vector pulse width modulation (SVPWM) is a common solution used to overcome traditional problems; such as stator flux ripple, electromagnetic torque ripple and gives more total harmonic distortion (THD) of the stator current. The actual paper is based on improving the performance of DTC-SVPWM by using the feedforward neural networks (FNNs) instead of the proportional-integral (PI) regulators and hysteresis comparators (HCs) of the conventional SVPWM strategy. This algorithm can solve the traditional PI regulators and HCs problems which are represented in responses dynamic and reduce the torque ripple, flux ripple, and the THD of stator current of FP-PMSM drives. The proposed strategy was tested in different tests with simulation using Matlab software.

Switching Regulation in the Control of 5-Phase Permanent Magnet Synchronous Motor Fed by 3×5 Direct Matrix Converter

Matrix converter is an AC-AC direct power converter comprising of an array of bi-directional switches. It does not require an intermediate DC-link and allows sinusoidal output waveforms with varying amplitudes and frequencies. The configuration of these bi-directional switches decides the number of inputs and outputs of the matrix converter. This research uses a direct matrix converter (DMC) as a phase-changing device that can convert a three-phase AC voltage into a 5-phase AC voltage. The DMC is modulated with the model predictive control algorithm. The output of DMC is fed to a five-phase permanent magnet synchronous motor (PMSM). The model predictive current control technique for DMC is carried out by developing a mathematical model of an input filter and PM motor used as a load. The predictive control of DMC results in sinusoidal output current, and it also enables the frequency variation in the output current. This frequency variation is useful in controlling the speed of the motor connected to the load. After controlling the 5-phase motor, the switching frequency regulation is done to observe its effect on the motor's stator current waveforms. Switching frequency regulation helps to limit the unnecessary switching of DMC. We developed a MATLAB-based Simulink model to study PMSM, and detailed results are presented. The results show that switching regulation can significantly reduce the switching frequency without compromising the current waveform quality.

Freewheeling Current-Based Sensorless Field-Oriented Control of Five-Phase Permanent Magnet Synchronous Motors Under Insulated Gate Bipolar Transistor Failures of a Single Phase

Model-based sensorless field-oriented control (FOC) suffers from overparameterization and can be laborious to use for a five-phase permanent magnet synchronous motor. On the other hand, insulated gate bipolar transistor (IGBT) frequently fails in an electric drive. Under IGBT failure, a freewheeling current is observed, and, above all, it carries the failed phase back electromotive force information. Based on this observation, this article presents the design of a brand new sensorless FOC by exploiting the freewheeling current to accommodate both IGBT and position sensor failures, which is expected to further enhance the drive's fault-tolerant capability. The mathematical model of this current is first established to provide a theoretical basis and a comprehensive understanding of the presented sensorless FOC. By virtue of this model, a second-order generalized integrator with a frequency-locked loop can be used as a simple and elegant way to extract position/speed estimates. Experimental results are provided to validate the proposed sensorless FOC philosophy.

Interturn Short-Circuit Fault Detection of a Five-Phase Permanent Magnet Synchronous Motor

Interturn short circuits are a common fault of permanent magnet synchronous motors (PMSMs). This paper proposes a new method to detect the interturn short-circuit fault (ISCF) of a five-phase PMSM. The method first takes the command voltage and measured current of each phase winding as the original signal and then obtains the delay signal orthogonal to the original signal via Hilbert transform. Then, the generalized instantaneous reactive power of each phase can be calculated from the orthogonal voltage and current signals of each phase. Finally, the influence of the ISCF on the generalized instantaneous reactive power of each phase is analyzed under different working conditions. By comparing the difference in the generalized instantaneous reactive power of each phase, it can be determined which phase winding has the ISCF. The proposed method is verified by simulated and experimental results.

Five phase permanent magnet synchronous motor decoupled model with dual frame frequency adaptive flux observer

In this paper, a five-phase permanent magnet synchronous motor (five phase PMSM) decoupled model is proposed to avoid the inaccuracy and computational complexity of conventional five phase PMSM model, which always ignores the mutual inductance between the fundamental and harmonic flux linkage. Unlike traditional inductances based five phase PMSM model, the proposed five phase PMSM decoupled model is built based on flux linkages. Moreover, to improve the accuracy of the proposed five phase PMSM decoupled model for model predictive control, a duel frame-frequency adaptive flux observer (DF-FAFO) is proposed, which can estimate both fundamental flux linkage and 3rd harmonic flux linkage online. The DF-FAFO can estimate the flux linkages accurately and minimize the unwanted harmonic ripple even if the torque is changed. The effectiveness of the proposed decoupled model and the DF-FAFO is demonstrated by simulations.

Modeling and fault diagnosis of multi-phase winding inter-turn short circuit for five-phase PMSM based on improved trust region

Multi-phase Permanent Magnet Synchronous Motors (PMSMs) are widely used in fault-tolerant control applications. As an electrical fault with a high probability, inter-turn short circuit (ITSC) fault seriously affects the reliability of five-phase PMSM. However, due to high coupling of fault parameters, most of the fault models and diagnosis methods in fault-tolerant control focus on one-phase winding ITSC fault of three-phase PMSM. In this paper, a novel model and a fault diagnosis method are proposed for multi-phase winding ITSC (MP-ITSC) of five-phase PMSM. First, by analysing the related physical parameters of the motor, a mathematic model of MP-ITSC fault is established. Then, a parameter estimation method based on improved trust region (ITR), which accelerates the convergence speed of trust region algorithm and reformulates the fault diagnosis as the extreme seeking for fault parameters is proposed to detect the ITSC fault level. Experimental results provide verification of the proposed model and fault diagnosis method.

Fault-Tolerant Control of Coil Inter-Turn Short-Circuit in Five-Phase Permanent Magnet Synchronous Motor

In the five-phase permanent magnet synchronous motor (PMSM) control system, the torque ripple caused by coil inter-turn short-circuit (ITSC)fault will make the motor performance worse. Due to the existence of the short-circuit current in the faulty phase and the third harmonic component in the permanent magnet flux linkage, the electromagnetic torque will contain even-order ripple components when the faulty phase is removed. Torque ripple also cause speed ripple. In this paper, the repetitive controller (RC) is used to perform proportional gain compensation for speed ripple. By designing the RC and connecting RC and proportional integral (PI) controller in parallel for the speed loop, the torque ripple amplitude can be reduced. It can be seen from the simulation and experimental results that the torque ripple suppression strategy based on RC can effectively suppress the torque ripple under ITSC fault.

Sensorless Speed Control of a Fault-Tolerant Five-Phase PMSM Drives

—This paper introduces a novel method to achieve sensorless speed control of a Five-phase Permanent Magnet Synchronous Motor (PMSM) drive in case of a single-phase open-circuit fault regardless which phase is open. The motor performance when an open circuit fault occurs is as good as it is before the fault. The degradation in motor performance, when an open circuit fault occurs, is minimized due to implementing a novel control technique that is using the four remaining healthy currents. This strategy includes introducing two software modifications to the operation of the five motor post the fault. Firstly, an asymmetric SVPWM is used post the fault instead of multi-dimension SVPWM that is used before the fault. Secondly, a new algorithm is introduced to track the saliency post the fault. The new algorithm is considering the application of the new modulation technique. Moreover, it uses only the excitation in the healthy currents of the motor due to the IGBT switching actions. Simulation results presented in this paper shows that the performance of the motor over a wide speed range and at different load conditions is maintained post the fault.

PWM Investigation of a Field-Oriented Controlled Five-Phase PMSM Under Two-Phase Open Faults

The decoupled model of Five-Phase Permanent Magnet Synchronous Motors (5Ph PMSMs) under a two-phase open circuit has been developed recently, yet the corresponding PWM has not been fully exploited. The Pulse Width Modulation (PWM), which is straightforward for a balanced system, can be problematic to fit a 5Ph PMSM under faulty conditions. During the open faults, the neutral voltage is drifting over the mid-point of DC bus, thus, the PWM typically designed for a balanced system always fails. In this article, an affine transformation is first presented to offset the drifting neutral effect, and only then PWMs can be effective. A quasi-sinusoidal PWM, a Space Vector PWM, and a min-max Carrier-based PWM are presented and compared experimentally. Each method has its own merits and demerits, and their effectiveness or rather the proposed affine transformation is validated by the experimental results.

Fuzzy Logic Based-Active Fault Tolerant Control of Speed Sensor Failure for Five-Phase PMSM

The present study seeks to investigate the problem of fault tolerant speed control of the five-phase Permanent Magnet Synchronous Motor (PMSM) in the presence of speed sensor fault. Indeed, the sensors which are the most sensitive elements play a significant role in the closed loop control. In this context, an active Fault Tolerant Control (FTC) is developed based on fuzzy controller. Using the Sliding Mode Observer (SMO), the reconfiguration scheme which alternates between the measured speed value and the estimated one is proposed during failure occurrences so as to preserve the best control performance. The five-phase PMSM is monitored by a fuzzy logic controller to reduce disturbances that can occur under fault conditions. The two techniques which are used to illustrate consistency in the proposed approach are the following: the sliding mode with encoder or without encoder-based control and the fuzzy logic control for efficient decision sent to the field-oriented control. Simulation tests, in terms of the measured and the estimated speed responses, have been carried out on the five phase PMSM drive. The results demonstrate that the proposed FTC scheme can validate the proposed FTC strategy and guarantee service continuity.

SMC based DTC-SVM control of five-phase permanent magnet synchronous motor drive

<span>This article presents an improved Direct Torque Control (DTC) technique with space vector modulation (SVM) for a five-phase permanent magnet synchronous motor (PMSM) using a sliding mode speed control (SMC).The proposed control scheme of the five-phase PMSM combines the advantages of SMC control and the SVM algorithm. The SMC method insensitive to uncertainties, in particular external disturbances and parameter variations. In this paper, the SMC controller is used to control the rotor speed of the five-phase PMSM based on DTC-SVM. The rotor speed response, torque and stator flux are determined and compared with traditional control method. The simulations results confirm the validity and effectiveness of the proposed control technique in terms of performance and robustness against machine parameter variations (inertia variation). The efficiency of the proposed method applied on the five-phase PMSM is verified by the MATLAB/Simulink.</span>