Five-phase Motor Research Articles

Analysis of Third-Harmonic Modulation Capability of Five-Phase Motor Drive and Near-Six-Vector SVPWM Algorithm

Analysis of Third-Harmonic Modulation Capability of Five-Phase Motor Drive and Near-Six-Vector SVPWM Algorithm

Active Disturbance Rejection Control of Five-Phase Motor Based on Parameter Setting of Genetic Algorithm

Five-phase induction motors have the characteristics of high torque density, low torque ripple, and flexible control, making them suitable for medium- and low-voltage power supply situations. However, with the expansion of application scenarios, five-phase motors need to cope with increasingly complex operating conditions. Five-phase motors for propeller propulsion will face various complex sea conditions during actual use, and five-phase motors for electric vehicles will also face various complex road conditions and operating requirements during use. Therefore, as a propulsion motor, its speed control system must have strong robustness and anti-disturbance performance. The use of traditional PI algorithms has problems, such as poor adaptability and inability to adapt to various complex working conditions, but the use of an active disturbance rejection controller (ADRC) can effectively solve these problems. However, due to the significant coupling between the variables of induction motors and the large number of parameters in the ADRC, tuning the parameters of the ADRC is complex. Traditional empirical tuning methods can only obtain a rough range of parameter values and may have significant errors. Therefore, this paper uses ADRC based on genetic algorithm(GAADRC) to tune the parameters of the control and design an objective function based on multi-objective optimization. The parameters to be adjusted were obtained through multiple iterations. The simulation and experimental results indicate that GAADRC has lower startup overshoot, faster adjustment time, and lower load/unload speed changes compared to the empirically tuned PI controller and ADRC. Meanwhile, using a genetic algorithm for motor ADRC parameter tuning can obtain optimal control parameters while the control parameter range is completely uncertain; therefore, the method proposed in this paper has strong practical value.

Predictive Stator Current Control of a Five-Phase Motor Using a Hybrid Control Set

Finite state model predictive control (FSMPC) of multiphase drives can use an extra number of inverter configurations compared with the three-phase case. This, however, requires more computing power for the optimization phase. The application time of each selected voltage vector (VV) is then increased, which can result in higher harmonic content. Reducing the allowed VVs can speed up the computations, thus ameliorating the current tracking/regulation in different orthogonal subspaces. However, the flexibility offered by the reduced set of VVs is less than that of the full set. Furthermore, a lower sampling time can result in an increase in the switching frequency, especially for some speed-load combinations. This article proposes the use of a hybrid scheme where the set of allowed VVs is not fixed but rather selected on-line according to the actual speed and torque producing stator current which are computed by the outer loop. A five-phase induction machine (IM) is used as a test bed for the proposal, showing improved results with respect to the nonhybrid case.

A Novel Three-Layer Symmetry Winding Configuration for Five-Phase Motor

This paper presents a new three-layer, five-phase winding configuration theory of unconventional slot-pole combinations by each layer of winding for a phase vector correction, three layers of winding superimposed together to achieve the results of three-phase symmetry. Since the single-layer unconventional winding has to have an empty slot to meet its symmetry, based on the characteristics of single-layer winding, the unconventional winding design is carried out. Based on the simulation comparison between the single-layer unconventional winding and double-layer unconventional winding, a three-layer, nine-phase unconventional winding is proposed, which is based on the theory of single-layer unconventional winding, and three layers are staggered and stacked to realize nine-phase winding, which not only increases the utilization rate of the winding slot but also improves the fault tolerance performance. In addition, a 105-slot, 20-pole, three-layer, five-phase motor is proposed for a winding configuration and performance analysis to achieve both low torque pulsation and high fault tolerance.

Performance Analysis and Evaluation of Multiphase Split-Source Inverters

Due to their many advantages over their counterparts, such as Z-source inverters (ZSIs), split-source inverters (SSIs) have recently received much attention as single-stage boost inverters. This paper discusses a multiphase version of the SSI topology for the first time. Among multiphase systems undergoing a revolution in the research area, five-phase motor drives are a relatively practical selection in industrial applications. Therefore, this paper focuses on a five-phase SSI as an example. The topology, operating principles, modulation techniques, and performance analysis of the analyzed topology are introduced. A modified space-vector modulation (MSVM) scheme is developed to eliminate low-frequency ripples in the input current. There is also a detailed analysis and graphical evaluation of the output currents ripples using the space-vector approach. It is evident that multiphase SSI is suitable for motor drives, especially when a high-output voltage gain is required. In addition to having a nearly identical ripple in output current to a conventional VSI, it has the benefit of performing the boosting action in a single stage with fewer passive components and a low ripple in input current. Finally, the simulation and experimental results have been conducted to demonstrate the viability of the multiphase SSI studied in the theoretical study and analysis.

Current Sensor Fault-Tolerant Control for Five-Phase PMSM Drives Based on Third-Harmonic Space

According to the different forms of back electromotive force, five-phase permanent-magnet synchronous motors (FPMSMs) can be divided into two types: sinusoidal FPMSMs (SFPMSMs) and trapezoidal FPMSMs (TFPMSMs). In field-oriented-controlled FPMSM drives, current sensors may malfunction in harsh working environments. In this article, two current sensor fault-tolerant control (FTC) strategies based on third-harmonic space, respectively, corresponding to SFPMSMs and TFPMSMs are proposed. Different from three-phase motor, the decoupled model of five-phase motor contains two orthogonal subspaces. The key to both strategies is that the third-harmonic space currents are controlled at zero when current sensors malfunction. Thus, the faulty phase current can be estimated with other phase currents by using the constraint equations of current transformation. For SFPMSMs, vector control and sinusoidal pulsewidth modulation technology are used to control the third-harmonic space currents to zero. For TFPMSMs, offset axis transformation and resonant observer are adopted for third-harmonic space current estimation and the third-harmonic space currents are controlled to zero by using the estimated values as feedback of vector control. The experimental results demonstrate that the robustness of both current sensor FTC systems is well performed in the whole speed range.

Research on Open Circuit Fault Modeling and Fault Tolerant Control Strategy of Five-Phase Induction Motor

Five-phase induction motors have the advantages of high reliability and strong fault-tolerant performance, so it’s open circuit fault model and fault-tolerant control strategy are widely studied. Based on the normal operation of the five-phase induction motor, the mathematical model of the five-phase induction motor under the conditions of single-phase open circuits, adjacent two-phase open circuits, and non-adjacent two-phase open circuits are established by using the reduced order decoupling transformation. Based on the principle of constant magnetic potential, the relationship between magnetic potential and each phase current is analyzed by using the symmetrical component method (MSC). The fault-tolerant control strategy of a five-phase induction motor with the above three open-circuit faults is designed. Through simulation and prototype experiments, the phase current and speed conversion under three open-circuit faults are analyzed. The results show that after the open-circuit fault of a five-phase motor, the residual phase current is no longer balanced, the motor speed is decreased, and the vibration is increased significantly. After fault-tolerant control, the residual phase current is balanced, the rated speed can be reached, and the vibration of the motor is reduced. Thus, the validity and correctness of the fault-tolerant control strategy for a five-phase induction motor are verified.

Sensorless Control of Five-Phase Permanent-Magnet Synchronous Motor Based on Third-Harmonic Space

Different from three-phase motor, the decoupled model of five-phase motor contains two orthogonal subspaces. In this article, a sensorless hybrid control strategy of five-phase permanent-magnet synchronous motor based on third-harmonic space with no need of motor parameters for whole speed range operation is proposed. At low-speed range, a high frequency pulse voltage is injected into the third-harmonic space to obtain the rotor position information, and the torque ripple is reduced by controlling the third-harmonic space current. Meanwhile, linear extended state observers are applied to replace the low-pass and band-pass filters for signal processing. At middle- and high-speed ranges, the back electromotive force at third-harmonic space is obtained to estimate the rotor position by controlling the third-harmonic space current. Compared with conventional methods, motor parameters and additional circuits are not needed. Software phase-locked loops are also adopted to estimate the rotor position. During the switch-over area, the two position estimation methods are both enabled for the sensorless control. The experimental results demonstrate that the robustness of the hybrid sensorless control system is well-performed in the whole speed range.

An Improved Model for Five-Phase Induction Motor Based on Magnetic Noise Reduction Part II: Pole-Slot Scheme

For the reduction in the electromagnetic noise level of three-phase induction motors, many empirical rules and analytical models have been established to select the matching scheme of pole and slot, but they are not fully applicable to five-phase squirrel cage induction motors (FSCIM). In this paper, combined with the slot-number phase diagram (SNPD), and the electromagnetic force-vibration-acoustic analytical model deduced in Part I, the influence of pole-slot schemes, including five-phase regular-size phase-belt and fractional-slot winding, on magnetic noise is analyzed. The feasibility of electromagnetic noise prediction is verified by finite element simulation and experiments. Taking a 4 kW FSCIM as a prototype, noise prediction is carried out for all the slot-number matching schemes with pole pairs not exceeding three. For two noise reduction targets, which reduce the maximum single-frequency noise in the steady-state operation and the average noise during startup, the pole-slot numbers matching rule of FSCIM is given. This improved model is also applicable in different power ranges for the noise reduction design of five-phase motors.

Performance Analysis of Five-Phase NPC MLI with Phase Shifting Carrier Pulse Width Modulation

The five-phase loads with Multi-Level Inverters (MLI) are preferred by industries in high and medium power applications due to lower switching loss, voltage stress across switches, etc. The controlling of a five-phase motor drive is done by Pulse Width Modulation (PWM) techniques. This paper discusses different multi carrier PWM techniques, such as Level Shifting Carrier (LSC) PWM and Phase Shifting Carrier (PSC) PWM techniques available for controlling the inverter drive. The simulation is carried out for all PWM techniques and load voltage, voltage THD, Common Mode Voltage (CMV), and DC-link voltages are noted and compared among the PWM techniques.

Investigation of the Properties of a Five-Phase Induction Motor in the Introduction of New Fault-Tolerant Control

Multiphase electric motors in cooperation with power semiconductor converters belong to the future of electric drives. This is because of their better properties compared to three-phase motors, such as better fault tolerance. How a multiphase motor will behave in a fault state is very important when using such motors in EV and HEV. This is the basis of the research in this article; we investigate the options for operating a five-phase motor in a fault condition in order to improve the drive qualities during fault operation. The complete mathematical expressions of the five-phase induction motor model in the normal operation as well as in fault operation and also the control modification to improve the properties of the drive are presented. The new five-phase field-oriented control is next described, which improves the drive qualities in four-phase operation and is the first fundamental aspect of the study. Another important aspect of the project is the development of a specific control on a real motor, followed by measurements of properties of a five-phase motor in normal and fault operation of one phase without and with control modification to enhance drive characteristics. The qualities and appropriateness of employing a five-phase motor as a drive in EV and HEV are then determined by comparing these results. Finally, a comparison of motor attributes is shown with and without control adjustment.

New SVPWM Used Post a Two-Phase Failure in FOC Five-phase PMSM Drives

One of the pronounced features of the multi-phase machines compared to the conventional three-phases machine is their high-fault capability. This merit is quite important as it contributes to minimizing the number of interruptions in industrial operations. This paper introduces two new Space Vector Pulse Width Modulation Techniques (SVPWM) to be used with the Field Oriented Control (FOC) strategy under two phases failure of the five-phase motor drives. The first SVPWM technique can be used if the failure happens to the adjacent phases while the second one is used in the cases that the failure happens to non-adjacent phases. The proposed modulation techniques are considering the modifications of the remaining healthy stator currents of the five-phase motor under the failure of the two adjacent phases and non-adjacent phases to maintain the torque producing Magneto Motive Force (MMF) and hence maintain the speed. This will enhance the reliability of the whole drive system. Also, the new SVPWM techniques will reduce the harmonics in the currents and hence reduce the ripple in the torque. Simulation results illustrate the capability of proposed new SVPWM techniques to maintain the torque ripple less than 3.6 % and 3.4% post the failure in adjacent phase and non-adjacent phases respectively.

Robust Predictive Current Control for Fault-Tolerant Operation of Five-Phase PM Motors Based on Online Stator Inductance Identification

The parameter mismatch in model predictive control (MPC), especially in fault-tolerant control, will lead to degradation of output performance. This article presents a new robust predictive current control based on online d-q inductance identification for a five-phase permanent-magnet (PM) motor under open-circuit fault. First, the MPC of the five-phase motor under the fault-tolerant operation of A-phase open-circuit is built, and then, the parameter mismatch caused by the d-q-axis inductance and the stator resistance is analyzed and discussed. Afterward, the real-time d-q-axis inductance identified by a fault-tolerance model reference adaptive system is used to replace the original parameters in MPC. Moreover, the flux linkage parameter mismatch can be rejected by the incremental predictive model in the proposed method. Therefore, the proposed method can eliminate almost all parameter mismatches, thereby improving output performance and enhancing parameter robustness under open-circuit fault. Finally, the validity and effectiveness of the proposed method are verified by experiments.

Simple Carrier-Based PWM for Prolonged High DC-Link Utilization for Symmetrical and Asymmetrical $n$-Phase AC Drives

Square voltage waveforms enable high dc-link utilization (DLU) in multiphase ac drives. Circulating-current filters were devised to attenuate the harmonics in no-torque low-impedance subspaces. Nonetheless, the square-wave harmonics that generate torque ripple are not reduced. Recently, it was proposed to combine circulating-current filters with a carrier-based pulsewidth modulation (PWM) method, which injects harmonics in no-torque subspaces (attenuated by the filter) of five-phase motors to achieve high DLU, without harmonics associated with torque ripple. The filter allows prolonged high-DLU operation without overheating. Compared with other PWM techniques capable of high-DLU operation (overmodulation), the one proposed for said filters is especially convenient because of its simplicity. However, it is unclear if this PWM method can be extended to machines of any phase number n and winding arrangement (symmetrical or asymmetrical); and if so, the resulting performance is also unknown. This article extends this simple carrier-based PWM strategy to n-phase drives, and evaluates its behavior in terms of DLU, distortion, and computational burden. Symmetrical and asymmetrical winding arrangements are considered. The improvement in DLU, compared with conventional PWM with zero-sequence injection, is considerable. Current distortion is negligible with a suitable filter. The simplicity over other high-DLU PWM techniques is remarkable. Experimental results are provided.

Пульсация потенциала общей точки трехфазной и пятифазной обмоток двигателя относительно «нуля» преобразователя

The aim of the study is to determine the parameters characterizing the ripple of a motor's three- and five-phase windings common point potentials (for the star winding connection diagram) with respect to the converter zero point. One of the reserves for decreasing electromagnetically induced vibration of an electric motor with a rotating field is to increase the number of working winding phases. The study subject is a five-phase motor winding connected to a bridge converter, namely, its ability to reduce electromagnetically induced vibration in comparison with that in using a three-phase winding. The common point potential ripple parameters are studied, and an approach is proposed to estimating the amplitude modulation of the space-time voltage vector of three- and five-phase windings under the influence of the common point potential ripple with respect to the converter zero point. Theoretical studies were carried out using the Fourier series expansion method and vector analysis methods. To confirm the theoretical results, experimental studies of the prototypes of three-phase and five-phase synchronous motors with inductors made on the basis of permanent magnets were carried out. The main results have shown the following. With increasing the number of phases of the rotating field motor working winding connected to a bridge converter, the common point potential ripple amplitude with respect to the converter zero point decreases, and the ripple frequency increases. The product of ripple amplitude by frequency remains unchanged. It is assumed that the common point potential ripple of the motor multiphase winding with respect to the converter zero terminal results in the amplitude modulation of the space-time voltage vector. With increasing the number of winding phases, the modulation amplitude decreases, and the modulation frequency increases. A five-phase motor has a lower level of the working winding common point potential ripple with respect to the converter zero point in comparison with a three-phase motor. Thus, it can be assumed that there will be a lower level of electromagnetically induced vibration in using a simple converter operation algorithm. The obtained results can be used in designing electric traction systems with vector control on the basis of multiphase motors. With increasing the number of phases, the common point potential ripple amplitude in a multiphase winding with respect to the converter zero point decreases, and the ripple frequency increases. Thus, the common point potential ripple amplitude in a five-phase winding is 5/3 times less than that in a three-phase winding, and the ripple frequency increases by 5/3 times, respectively. With increasing the number of working winding phases, the amplitude modulation of the resulting space-time voltage vector decreases. This circumstance has a positive effect on decreasing the electromagnetically induced vibration.

Алгоритмы управления пятифазного преобразователя, реализующие пространственно-векторную модуляцию

Multiphase (five-phase) motors can be considered as an alternative to three-phase motors in implementing electric traction with vector control. The subject of the study is the five-phase winding voltage vector space formed by various control algorithms of a five-phase converter. Thirty logical states of the converter form three types of the vector voltage space of a symmetrical five-phase winding. Each of the vector space types forms the resulting vector of a certain value. The resulting (generalized) voltage vector can take three different values. With the phase time sequence ABCDE of a symmetrical five-phase winding ABCDE with the spatial phase shift equal to 72 electrical degrees, the fundamental harmonic vector is the resulting working voltage vector. With the phase time sequence ACEBD of a symmetrical five-phase winding ABCDE with the spatial phase shift equal to 72 electrical degrees, the resulting voltage vector of the third harmonic is the resulting working vector. The rotation frequency of the resulting third harmonic vector is three times the rotation frequency of the fundamental harmonic vector, and the rotation direction is opposite to the rotation direction of the fundamental harmonic vector. With one of the phase voltage forms and the phase time sequence ACEBD, the modulus of the resulting voltage vector of the third harmonic component is equal to the modulus of the resulting vector of the fundamental harmonic component. There are two converter control algorithms that form the resulting voltage vectors that are equal in modulus, but with different rotation speeds multiple of three. An approach to studying the multiphase phase winding voltage vector space has been elaborated, which can be applied in implementing vector control.

Research on Vector Sequence Optimization of Five-phase SVPWM

In the multi-phase motor drive system, the five-phase motor is the typical representative. But the increase of the number of phases causes the number of IGBTs used by the inverter multiplied, and the use of SVPWM control with high frequency on and off causes the inverter switching loss increased, thus the inverter produces a lot of heat. In this paper, by adjusting the action order of effective vectors in SVPWM and the insertion position of zero vectors, a vector sequence optimization SVPWM technology is proposed. Compared with the conventional NFV-SVPWM technology, under the same frequency the switching times are reduced to 40% of NFV-SVPWM. The vector sequence optimization SVPWM and five-phase induction motor was simulated in Simulink. The simulation showed that the vector sequence optimization SVPWM introduced few harmonic content and the stator phase current distortion of the motor was low.

Basic Comparison and Evaluation of Functionality AC-AC Matrix Converter Concepts for HEV Vehicle - Part II

The paper deals with a modeling and simulation of the direct AC-AC propulsion system and compares two matrix converter concepts with five-phase traction induction motors (IM) for the hybrid electric vehicle (HEV). The simulation results of [3x5] matrix converter and 4Q-converter are done using Matlab-Simulink environment. Part I deals with a theoretical study of converter concepts for hybrid electric vehicle, since the configurations of [3x5]+[0x5] matrix converters with five-phase motor(s) have not been analyzed so far. Based on simulation results the comparison and evaluation of the property and quality of the quantities of different type of the matrix powertrain are discussed in Part II.

Basic Comparison And Evaluation Of Functionality AC-AC Matrix Converter Concepts For HEV Vehicle - Part I

The paper deals with the direct AC-AC propulsion system and compares two matrix converter concepts with fivephase traction induction motors (IM) for the hybrid electric vehicle (HEV) including electronic differential. The first one consists of [3x5] matrix converter and [3x1] active PWM rectifier (4Q-converter) for full power performance. The second one comprises one [3x5] matrix converter for full power and auxiliary [0x5] matrix converter for partial output
 power. Configurations of [3x5] + [0x5] MxC converters with five-phase motor(s) are not analyzed in available literature so far. The advantage of the proposed connection is in supposed higher efficiency of matrix converter then clasiccal VSI one. Part I deals with a theoretical study of converter concepts for hybrid electric vehicle. Based on simulation results the comparison and evaluation of the property and quality of the quantities of different type of the matrix powertrain are discussed in Part II.

Sensorless Control for Five-Phase IPMSM Drives by Injecting HF Square-Wave Voltage Signal into Third Harmonic Space

Compared with the conventional three-phase motor, the five-phase interior permanent magnet synchronous motor (IPMSM) has better advantages on fault-tolerance due to redundant freedom. In order to obtain further fault-tolerance, this paper proposes a new high frequency (HF) signal-injection-based sensorless control strategy for five-phase IPMSM drives. The key is to extend the position sensorless technology based on HF signal injection into the five-phase motor control system, especially proposing a sensorless control method by injecting a HF square-wave voltage signal into the third harmonic space. The induced HF current responses in the third harmonic space can be utilized to track the rotor speed and position accurately. Compared with the conventional HF sinusoidal signal injection methods, the proposed method can effectively reduce the influence of digital filters, such as time delay and decreased performance because the low-pass-filter (LPF) is removed. In addition, the torque ripple caused by the proposed injection method in third harmonic space is reduced compared with the method in fundamental space. The effectiveness of the proposed method is verified by simulation and experimental results.