Permanent Magnet Synchronous Machine Research Articles

SCADA based common bus regenerative control of PMSM drive for industrial application

AbstractThe emerging trend in sustainable industrial processes focuses on energy‐efficient drives to enhance performance in both intermediate and continuous operating conditions. For decades, researchers have focused on permanent magnet synchronous machines (PMSM) for industrial applications in order to retain consistency in performance and efficiency under wide speed ranges. Common bus regenerative control is an energy‐efficient method used in industrial systems to manage power flow between multiple devices on a shared DC bus. It captures and reuses excess energy generated during braking/deceleration, reducing waste and improving overall system efficiency. The experimental behavior of the drive scheme has been observed as per the standards of the laboratory. In this article, regenerative control of a PMSM drive is using the voltage vector control (VVC+) technique and the SCADA based condition monitoring for the PMSM drive system is integrated to supervise the parameters including current, voltage, power, speed, torque, and temperature under dynamic operating conditions. As a primary step of implementing the drive condition monitoring is carried out through Danfoss's motion control tool software. Further, the SCADA control system is interfaced to FC302 PMSM drive through RS485 Modbus communication to extract the necessary electrical attributes and monitor the same.

Why state-of-the-art analytical models for eddy current losses in PM of PMSM are insufficient for variable speed motors

This is the third paper in a series on novel methods for calculating eddy current losses in permanent magnets (PM) and the shortcomings of previously conducted analyses. In the first paper, Ruoho’s work on homogeneous materials was discussed. The distribution of fields has been expanded to include the reaction field of the eddy currents within the permanent magnets. This approach was based on the methods of the harmonic complex AC calculation. In the second paper, the models were expanded to enable a harmonic calculation of eddy current losses in permanent magnets for homogeneous fields including the effects of eddy current losses in an adjacent ferromagnetic material, leakage flux factors, and source behavior. In this third and final publication, a look at state-of-the-art analytical models will be taken. With regard to the results of the second publication of this series, it can be shown that established analytical models are insufficient when calculating inverter-related eddy current losses in permanent magnets of permanent magnet synchronous machines (PMSM). Furthermore, a short introduction to eddy current loss mechanics in permanent magnets of PMSM will be given.

Full harmonic spectrum calculation of magnetic pressures in synchronous permanent magnet machines based on a new realistic partial analytical model: application to SVPWM and DPWM2

PurposeThe purpose of this paper is to propose a new method that allows to compare the magnetic pressures of different pulse width modulation (PWM) strategies in a fast and efficient way.Design/methodology/approachThe voltage harmonics are determined using the double Fourier integral. As for current harmonics and waveforms, a new generic model based on the Park transformation and a dq model of the machine was established taking saturation into consideration. The obtained analytical waveforms are then injected into a finite element software to compute magnetic pressures using nodal forces.FindingsThe overall proposed method allows to accelerate the calculations and the comparison of different PWM strategies and operating points as an analytical model is used to generate current waveforms.Originality/valueWhile the analytical expressions of voltage harmonics are already provided in the literature for the space vector pulse width modulation, they had to be calculated for the discontinuous pulse width modulation. In this paper, the obtained expressions are provided. For current harmonics, different models based on a linear and a nonlinear model of the machine are presented in the referenced papers; however, these models are not generic and are limited to the second range of harmonics (two times the switching frequency). A new generic model is then established and used in this paper after being validated experimentally. And finally, the direct injection of analytical current waveforms in a finite element software to perform any magnetic computation is very efficient.

Single-Phase Charging of Six-Phase Integrated On-Board Battery Charger Using Predictive Current Control

Integrated On-Board Battery Chargers (IOBCs) have shown promise as an elegant charging solution for electric vehicles in recent literature. Although the three-phase charging technique of IOBCs has extensively been discussed in the literature, single-phase charging is still a challenging research topic. The Predictive Current Control (PCC) approach has shown many benefits, including a straightforward algorithm, simple implementation, comparatively quick response, and appropriate performance, when compared to conventional control techniques. This paper investigates the impact of single-phase charging of a six-phase-based IOBC system with different winding configurations using PCC, which, up to the best authors’ knowledge, has not been conceived thus far. Under single-phase charging, the zero-sequence current component is utilized to ensure zero torque production during charging mode. Since the impedance of the zero subspace is highly affected by the employed winding design, the performance of PCC with different winding layouts of either induction machine (IM) or permanent magnet synchronous machine (PMSM) is investigated and compared. The proposed method is experimentally validated using a 1.1kW six-phase IM and a 2 kW 12-slot/10-pole PMSM. Finite Element analysis is also carried out to investigate the effect of single-phase charging mode on the induced radial forces and vibration level when PM machine is employed.

Armature MMF Reconfiguration Method of Six-Phase Integral-Slot PMSMs for Zero-Order Vibration Reduction Under Open-Circuit Faults

It is well known that the vibration performance of the permanent magnet synchronous machines (PMSMs) will deteriorate under the open-circuit fault operation. However, the cause of the vibration deterioration and corresponding methods to reduce the vibration are still unclear. This paper reveals the reason of the zero-order vibration deterioration for integral-slot six-phase PMSMs open-circuit fault operation. Furthermore, a magnetomotive force (MMF) reconfiguration method is proposed to suppress the fault-resulted zero-order vibration. The key is to eliminate the fundamental backward-rotating MMF, which contributes to the fault-resulted zero-order radial force under the open-circuit fault operation. With the aid of the response surface method, the analytical expressions of the optimal reconfigured current are derived considering all four open-circuit fault types. Compared with the conventional method, the fault-resulted zero-order radial force is greatly weakened by adopting the proposed method. Finally, the prototype of a six-phase 72-slot/12-pole PMSM is manufactured. The current and vibration tests are carried out to validate the theoretical analysis.

Open-Phase-Tolerant Online Current References for Maximum Torque Range and Minimum Loss With Current and Torque-Ripple Limits for n-Phase Nonsalient PMSMs With Nonsinusoidal Back EMF

Multiphase permanent-magnet synchronous machines (PMSMs) with nonsinusoidal back-electromotive force (back-EMF) offer high fault tolerance and torque density for electric vehicles. Most current-reference generation methods either minimize stator copper loss (SCL) or maximize achievable torque. Optimization of both goals is accomplished by full-torque-range minimum-loss (FRML) strategies, but so far just for sinusoidal back-EMF. Thus, FRML for nonsinusoidal back-EMF should be sought. Moreover, many methods are only suitable for healthy conditions or specific machines, harmonics, or open-phase-fault (OPF) scenarios. Additionally, the torque range may be extended by permitting torque ripple or (transiently) greater rms current, but this approach is not general nor FRML yet. This paper proposes online FRML current-reference generation for multiphase PMSMs with nonsinusoidal back-EMF: nonsinusoidal-back-EMF FRML (NSBE-FRML). When the torque reference is feasible, minimum SCL is attained while maximizing the achievable torque (i.e., FRML). For higher torque references, the instantaneous torque deviation is minimized, and the torque reference is saturated in consecutive samples limiting the torque ripple to a pre-specified threshold. Furthermore, the rms current is limited after transient overload by automatically decreasing the torque reference. The NSBE-FRML is suitable for any harmonics, healthy/OPF conditions, and multiphase PMSMs with negligible saliency ratio. Experiments are performed with a six-phase PMSM.

Open-Circuit Fault-Tolerant Control for Pentagon Winding Connected Five-Phase Current-Source Inverter Based PMSM Drives

Current-source inverter (CSI) is considered as a prospective solution for modern machine drives, for its higher reliability and superior harmonic suppression. The open-circuit fault-tolerant control for five-phase CSI-fed permanent magnet synchronous machine (PMSM) drive with pentagon winding connection is investigated. The switch open-circuit fault and winding open-circuit fault are studied. For the switch open fault, three cases are discussed including single-phase, adjacent two-phase, and nonadjacent two-phase faults. It is indicated that in pentagon circuit, despite the switch of fault phase is disabled, the corresponding phase winding is still connected in the end-to-end power circuit and contributes for torque generation. The new sets of coordinate transformation are proposed, and the mathematical modeling is presented. The fault-tolerant space vector modulation (SVM) techniques are proposed based on the reconstructed vector planes. In addition, the single winding open fault is studied, which is a specific fault case and breaks off the closed pentagon connection. An important conclusion is derived that the pentagon winding connected CSI (PWC-CSI) gains inherent fault-tolerant capability against the single winding open circuit. The control algorithm even does not need to be switched during this typical fault. Experiments are performed on verifying the proposed schemes.

Comparative Investigation of Dual Three-Phase Permanent Magnet Synchronous Machines With Different Winding Configurations

Comparative Investigation of Dual Three-Phase Permanent Magnet Synchronous Machines With Different Winding Configurations

Analytical Solution of Magnetic Field in High-Speed Permanent Magnet Synchronous Machines With Novel Composite Rotor

Analytical Solution of Magnetic Field in High-Speed Permanent Magnet Synchronous Machines With Novel Composite Rotor

Comparison of Permanent Magnet Synchronous Machines for Hybrid Light Aircraft with traditional and additive winding technologies

Electrical motors are key components in the electrical transition required for greenhouse gas reduction programs. Future aircraft will certainly employ electrical motors for primary and secondary surface control, for landing gear and for other actuations such as high-lift systems, and they will also need electrical motors for propulsion. The motors pose the hardest challenge due to the high-power density required. Hybrid-Electric propulsion represents one of the most important topics in the aerospace industry and offers an opportunity to pursue the electrification change especially in light aircraft segments. The focus of this paper is the comparison among permanent magnet synchronous motors for Hybrid Light Aircraft propulsion with traditional and additive winding technologies.

A composite sliding mode control with the first-order differentiator and sliding mode observer for permanent magnet synchronous machine

This paper proposes a composite sliding mode control (SMC) to optimize the tracking performance and the anti-disturbance performance of permanent magnet synchronous machine (PMSM) speed regulation systems. The differential term in the control law can magnify the measurement noise, resulting in more discontinuity. To filter out the high frequency noise and make the control law smoother, the first-order differentiator (FOD) is employed to estimate the speed error and its derivative. Since the feedforward compensation can improve the robustness of the system, a disturbance observer (DOB) based on the sliding mode observer (SMO) is designed to reinforce the dynamic performance under disturbance variation. Under the effect of the feedforward compensation, chattering can be further weakened by decreasing the switching gain appropriately. Finally, the effectiveness of the proposed methods is confirmed by various experimental results.

Driving a Symmetric Permanent Magnet Synchronous Six-Phase Machine with Consecutive Three Phases

This paper investigates a driving method for a Permanent Magnet (PM) Synchronous six-phase machine by using its consecutive three phases. The torque of PM synchronous machine is the division of instantaneous power (I-power) of the machine to the rotor speed. The I-power of a machine gives information about the torque. The torque output of a PM synchronous machine can be predicted by looking at the I-power. This study investigates the torque of a PM synchronous six-phase machine by exciting its phase coils for the combination of conventional three-phase, double conventional three-phase, consecutive three phases of six-phase machine and double consecutive three phases of six-phase machine. This paper also investigates the way of driving a six-phase machine using the balanced three-phase supply. Firstly, analytical studies have been done for these exciting combinations. These analytical results indicate that symmetric six-phase machine can be driven using these combinations. Secondly, a PM synchronous six-phase machine has been designed in a finite element analysis (FEA) software. Lastly, that designed six-phase machine excited with these combinations to observe the torque wave form of the machine. As a result of this study, a symmetric six-phase machine can be run by its consecutive three phases without torque ripple.

Parameter Identification for Maximum Torque per Ampere Control of Permanent Magnet Synchronous Machines under Magnetic Saturation

This paper applies the identified parameters of permanent magnet synchronous machines (PMSMs) for the maximum torque per ampere control (MTPA) under magnetic saturation. The variation in magnet flux with current is determined using a position offset approach while the variation in q-axis inductance with the current is estimated from the d-axis voltage equation afterward. In addition, the d-axis inductance is estimated at standstill by the injection of a small amplitude of high frequency d-axis current. The curve-fitted results of estimated parameters under different saturation conditions are then employed to aid the derivation of MTPA control law. The proposed method is experimentally verified on two prototype PMSMs. Experimental results show that compared with conventional MTPA schemes using fixed values of magnetic parameters, the proposed method can increase maximum output torque by 2.1% and 3.2% on two prototype PMSMs, respectively.

Design and Optimization of a Five-Phase Permanent Magnet Synchronous Machine Exploiting the Fundamental and Third Harmonic

This paper deals with the design of five-phase permanent magnet synchronous machines (PMSMs) exploiting the third harmonic for torque generation. Through the optimization of the stator size and rotor structure, the objective functions related to mass and electric losses are minimized for a targeted electromagnetic power (10 kW and 400 rpm) and a given volume. The study takes into account saturation, thermal, electrical and mechanical constraints. On that note, a 1D analytical magnetic model, considering the existence and use of the third harmonic, is presented. The design optimization then shows how the use of harmonic 3 can improve the machine’s performance. It will be shown that, for a given electromagnetic torque, taking the third harmonic into account in the sizing process leads to a mass reduction that can reach 20% and electrical losses that can go up to 21%. A finite element analysis model of the five-phase PMSM is then established in order to verify the results of the optimization and validate them.

Nonlinear Magnetic Model of IPMSM Based on the Frozen Permeability Technique Utilized in Improved MTPA Control

In this paper, the enhanced nonlinear magnetic model of the low voltage interior permanent magnet synchronous machine (IPMSM) is developed using the frozen permeability (FP) technique in finite element analysis (FEA) FEMM 4.2 software. The magnetic model is derived by obtaining flux saturation maps for a wide range of dq stator currents. Furthermore, the FEA FP technique accounts for the corresponding offset in the flux maps due to the excitation of the permanent magnets, and well as for fitting the coefficients for the curve-fitting procedure. In order to demonstrate the usefulness of the proposed magnetic model, a nonlinear control strategy based on the maximum torque per ampere (MTPA) optimal algorithm for IPMSM is employed. The magnetic model and the MTPA control strategy are validated through a variety of computer simulations based on FEMM 4.2 and MATLAB R2023a software, as well as on a real IPMSM electric vehicle (EV) traction drive experimental setup.

High Bandwidth Current Regulator Design for PMSM Based on Frequency Sweep Correction

How to automatically correct controller para- metric mismatch and improve motor current closed-loop bandwidth in gain scheduling is an important issue for general motor drives. This paper firstly introduces the frequency domain tuning method of current controller. Then, the time delay identification and model parameters self-correction method based on frequency sweep is introduced to avoid the influence caused by parameter mismatch between plant and controller model. On this basis, phase lead module combined with active resistance term, is designed as a prefilter for current regulator, so as to achieve faster current dynamic response and improve disturbance rejection. Finally, the parameter setting for proposed current regulator is introduced to better practice. Experiments for different permanent magnet synchronous machines are carried out on a miniature drive system, the results fully verify the effectiveness of proposed scheme.

Comparison and research on load characteristics of PM in different permanent magnet synchronous machines

PM enable PMSMs to have higher torque-density and power-density, however the machine performance is closely related to its load characteristics. When the armature excitation does not match the load characteristics of the PM and machine, it can lead to demagnetization and performance degradation. By comparing and studying the IPMSM’s and SPMSM’s load characteristics, a more reasonable machine topology of components such as PM can be obtained, and high-performance machines can be designed more efficiently. Based on the material characteristics of the PM, the armature reaction law of different machines and the demagnetization law of the PM at different current angles were analyzed. There are different magnetic field distribution patterns in IPMSM and SPMSM, and their different load characteristics are compared to study the methods for improving the anti-demagnetization ability of PMs based on different machine structures.

Design and FEA analysis of hub based dual rotor machine for optimal energy generation in four wheeled electric vehicle application

This research article focuses on the design and Finite Element Analysis (FEA) analysis of a hub-based Dual Rotor Machine (DRM). Conventional, electric machines can perform either motoring or generating operations at an instant of time for electric vehicle (EV) applications. However, the proposed DRM can perform both motoring and generating modes of operation simultaneously. For this dual operation, a power rating of 15 kW Brushless DC Machine is selected with outer rotor configuration to achieve high starting torque in motoring operation and a power rating of 6 kW Permanent Magnet Synchronous Machine is considered for generating operation with an inner rotor. Based on theoretical results, the design of DRM is developed and analysed using FEA software programs such as MagNet, Jmag and ThermNet. By using a two-dimensional (2-D) transient solver, the proposed DRM performance is simulated and validated with cogging torque, electromagnetic, thermal and stress analysis. The performance of the proposed DRM model is also tested with drive cycle data of WLTP-II (Worldwide Harmonised Light Vehicle Test Procedure) in ANSYS Motor-CAD software. The simulation results confirm the proposed DRM can consume only 252 Wh over 405 Wh energy consumed by a single rotor machine and ensuring its applicability for EV applications.

The Financial Aspects behind Designing a Wind Turbine Generator

This article investigates the construction of a wind power generator requiring the lowest possible cost. The proposed model is an Axial Flux Permanent Magnet (AFPM) Synchronous Machine, which contains two iron rotors and a coreless stator between them, constructed from resin. The scientific contribution relates to the coupling of economic and technical parameters, which will clarify the feasibility, i.e., a wind turbine construction capable of producing approximately 3.5 KW, using a simple mill and a generator of nominal rotor speed 100 rpm. Such studies are few in international literature and mainly concern low levels of rotor speed in relation to the produced output power. For the generator dimensioning, analytical equations are used, while the type and the dimensions of the magnets are determined, before the start of dimensioning. The authors carried out research in the international market, ending up with specific cost-effective magnets, while trying to adjust the remaining dimensions and materials of the machine based on these cost-effective magnets and the aforementioned nominal values of the generator. The machine, whose dimensions are derived by analytical equations, was simulated and analyzed using the Two-Dimensional Finite Element Method (2D-FEM) and the Three-Dimensional Finite Element Method (3D-FEM), for comparison purposes. Moreover, an economic analysis of the generator and its individual parts was conducted. Finally, a novel idea for reducing the total generator cost is proposed, by replacing the rotor disks with rings. The investigation revealed that analytical equations can predict with satisfactory accuracy the generator’s parameters. In addition, as permanent magnets are the most expensive materials in the construction, their predetermination using low-cost magnets can reduce the construction cost. Finally, the proposed concept of a ring-shaped rotor instead of a disk rotor, provides a cost reduction of up to 20%.

Thermal analysis and temperature evaluation on a magnetic‐geared dual‐rotor machine

AbstractThe thermal performance of the magnetic‐geared dual‐rotor machine (MGDRM) is investigated. Because the effective component in the outer airgap magnetic field harmonics is low, the torque production of MGDRM cannot match the regular permanent magnetic synchronous machine (PMSM). Although the analysis shows that the torque generation of the MGDRM is weak, this conclusion is limited in the electromagnetic field. The MGDRM outer rotor should also be considered from the thermal aspect, and the effect on the torque generation should be valued in particular. The outer rotor thermal buffer effect blocks the heating flow from the winding to the inner rotor magnets. Thus, the MGDRM can withstand a heavy electrical load in a short period, producing higher torque. With this understanding, the torque production ability of the MGDRM can extend to a higher level, even close to the regular PMSM. To validate the analysis, a MGDRM machine is prototyped, and the dual‐rotor temperature information acquisition is realised by a wireless data collection. The rotor temperature estimation technology on the dual‐rotor is then investigated as an auxiliary function. The estimation error can be limited around 5°C, which is good for warning the thermal risk. And thus the MGDRM overheating can be safely adopted to extend the torque generation.