High-speed Permanent Magnet Synchronous Generator Research Articles

A Novel Current Harmonic Suppression Method for HSPMSG Based on the Hybrid Rectifier

This paper presents a novel current harmonic suppression scheme for the high-speed permanent magnet synchronous generator (HSPMSG). Aiming to effectively reduce current harmonics for the HSPMSG, this paper focuses on two areas: improving the rectifier power topology and developing a current loop controller. Firstly, a hybrid rectifier based on Silicon-Carbide/Silicon (SiC/Si) is designed to equivalently increase the switching frequency of the HSPMSG to address the problem of low carrier frequency ratio. In addition, an improved space-vector-modulation (ISVM) strategy based on the hybrid rectifier is proposed. However, the harmonic distortion caused by rectifier nonlinearity will deteriorate as the switching frequency is increased. For further suppressing harmonic disturbances caused by rectifier nonlinearity, a resonant-super-twisting (R-STW) controller is designed by combining the resonant controller and the super-twisting (STW) controller in this paper. The stability of the STW is demonstrated by Lyapunov stability theory and the resonant controller is discretized. Finally, a number of simulations and experiments based on a high-speed permanent magnet synchronous generator are carried out to verify the effectiveness of the control method proposed in this paper.

Super Twisting Control Design for HSPMSG Voltage Stabilization Based on Disturbance Observation Compensation

For the purpose to solve the problem of poor anti-disturbance performance and large voltage fluctuations of the high-speed permanent magnet synchronous generator (HSPMSG), this paper proposes a compound control method. The method combines the super-twisting (STW) voltage outer loop controller with the super-twisting disturbance observer (STWO). First, in order to overcome the problem of poor anti-disturbance performance under the conventional PI control method, a voltage outer loop controller based on the STW is designed. Second, a load disturbance observer based on the STW is developed for further improving the anti-load disturbance capability of HSPMSG. The estimated value of the disturbance observer is feedforward into the STW controller as a compensation term. Finally, both simulations and experiments are performed on a HSPMSG to verify the effectiveness of the proposed control strategy.

Optimal design of high-speed permanent magnet synchronous generator based on NSGA-II considering mechanical properties

Although the finite element method (FEM) is highly reliable, it is time-consuming and expensive, for example, substantial computing costs are incurred for coupled analysis while considering the mechanical and electromagnetic properties. Therefore, in this paper, a high-speed permanent magnet generator's electromagnetic and stress characteristics have been mathematically derived, and the optimal point is selected based on NSGA-II. The objective functions are power density and efficiency, with the constraints being the current density, slot fill factor, core saturation, voltage limit, and rotor safety factor. The method presented in this study was verified via FEM analysis and experimental results of the optimal model.

Accurate Calculation of Iron Loss of High-Temperature and High-Speed Permanent Magnet Synchronous Generator under the Conditions of SVPWM Modulation

The high-temperature and high-speed permanent magnet synchronous generator (HTHSPMSG) is the core component ensuring the efficient and safe operation of the high-speed aircraft power supply system. At present, the existing iron loss model fails to meet the requirements for the precise calculation of the iron loss of HTHSPMSG under high-temperature and high-frequency conditions. In this paper, a 40 kW, 18,000 rpm HTHSPMSG is used to study the accurate calculation of iron loss at an ambient temperature of 350 °C. Considering the influence of high temperature and high frequency on the loss and performance of electromagnetic materials, a test platform for the loss performance of the magnetic core materials is established. Then, according to the loss performance of the electromagnetic material, the corresponding iron loss coefficient is fitted by the variable coefficient iron loss separation model. In addition, the digital twin field-circuit co-simulation method is proposed to guarantee the accuracy of the iron loss calculation. Then, the influence of carrier frequencies and modulation ratios on the iron loss characteristics of the HTHSPMSG under the conditions of SVPWM modulation is studied. Lastly, the effectiveness of the proposed method is verified by the experimental results, which provide a reference for the accurate analysis of iron loss of the same type of HTHSPMSG.

Taguchi Method for Design and Optimization of a High-Speed Permanent Magnet Synchronous Generator Protected by Retention Sleeve

High-speed permanent magnet synchronous generators (HS-PMSGs) suffer from mechanical stresses due to high speeds. With the predicted mechanical stresses that may occur in the rotor of the HS-PMSGs, the design of these machines should be very accurate. So, for the HS-PMSGs, a proper electromagnetic coupled with mechanical design is a critical issue. This paper presents a novel method for the electromagnetic and mechanical design of an HS-PMSG by finding an appropriate dimension of the retention sleeve and permanent magnets (PMs) based on the well-known Taguchi optimization method. A 40-kW, 60-krpm, 2-poles and 18-slots HS-PMSG is designed at the first step, and next, it has been optimized by the proposed optimization method, and finally modeled and analyzed through Finite-Element Method (FEM). Results obtained from the electromagnetic and mechanical simulations of the HS-PMSG show that in the optimized design of the HS-PMSG some parameters changed and the HS-PMSG has a better performance compared to the initial design. For example, The effective air gap has been reduced which leads to the better electromagnetic and mechanical performance of HS-PMSG compared to the initial design. By the reduction in the thicknesses of the retention sleeve and the PM, it can be concluded that the total size and dimensions of the HS-PMSG have been reduced. The weight of the PM and the retention sleeve are reduced by about 16.31% and 29.28% responsively, and as a result, the total weight of the HS-PMSG is reduced by approximately 1.94%, The Joule loss is reduced by about 9.80%, the HS-PMSG efficiency has been improved by 0.02%, and finally, the cogging torque is reduced by 27.87%, comparing with the initially designed. The FEM results ensure the electromagnetic and mechanical performance of the machine around the predicted speed of 60-krpm.

Design and Modeling of a High-Speed Permanent Magnet Synchronous Generator with a Retention Sleeve of Rotor

In this paper, the authors present a novel approach to design a high-speed permanent magnet synchronous generator (HS-PMSG) with a retention sleeve. The importance of the retention sleeve becomes conspicuous when the rotor suffers from the radial and tangential stresses derived from a high speed say 60 krpm. With respect to the mechanical property of Titanium, this material has been demonstrated that it could be a proper material for the retention sleeve. The investigations of this paper are concentrated on the electromagnetic coupled with mechanical design of a 2-poles, 18-slots, 40 KW HS-PMSG which is carried out through FEM analysis using JMAG 17.1 and ABAQUS CAE and optimized through the well-known Taguchi optimization method. The obtained results assure the robust mechanical behaviour of the HS-PMSG at a rotational speed of about 60 krpm meanwhile the cogging torque, the Joule loss, and the total weight of the optimally designed HS-PMSG are reduced 44.71%, 27.87%, and 2.78%, respectively compared with the initial design.

Design of the High-Speed PMSG with Two Different Shaft Material Considering Overhang Effect and Mechanical Characteristics

In general, high-speed machines should be designed to satisfy electromagnetic and mechanical characteristics. In this study, the design of high-speed permanent magnet synchronous generator with two different shaft materials considering overhang effect and mechanical characteristics was performed. It was confirmed that the leakage magnetic flux generated by the two shaft materials electromagnetically affects the high-speed generator. Additionally, it is important to accurately predict the natural frequency mode and critical speed to prevent damage and vibration of the rotating body owing to scattering during high-speed rotation. Therefore, the mechanical characteristics of the designed model were analyzed. In this study, we propose a design method that considers both the electromagnetic effects and mechanical characteristics. Subsequently, verification was performed through experiments and comparisons for the validity and reliability of the proposed design method.

Experiments and Design Criteria for a High-Speed Permanent Magnet Synchronous Generator With Magnetic Bearing Considering Mechanical Aspects

In this work, the design and experimental analysis of a high-speed permanent magnet (PM) synchronous generator (PMSG) with a magnetic bearing without mechanical friction were performed. The rotor size was derived using the torque per rotor volume method and an analytical method. Rotor structure analysis was performed to verify the validity of the selected sleeve and PM thickness. The magnetic bearing was designed considering the input aerodynamic force and DN-factor. Then, the validity of the proposed design method was verified through the electromagnetic and mechanical analysis, design, and comparison with the experimental results of a high-speed PMSG (124 kW and 36 krpm).

Design and Analysis of High-Speed Permanent Magnet Synchronous Generator With Rotor Structure Considering Electromechanical Characteristics

In high-speed permanent magnet synchronous generator (PMSG), the rotor design should not only ensure mechanical stability at high speeds but also ensure the required electromagnetic (EM) performance. This paper deals with the EM analysis and design of high-speed PMSGs considering the rotor structure. In particular, the effects of active power and output voltage due to internal impedance from leakage flux are presented. The relationship between design variables of rotor and performance is analyzed using three-dimensional static finite element analysis and simplified equivalent circuit method. Based on the analysis results, a model with improved EM performance using a nonmagnetic pad is presented according to design parameters of rotor structure. The EM performance and the mechanical reliability of the designed model are validated by comparing the FE results with experimental results.

Characteristics analysis of a high-speed permanent magnet synchronous generator considering magnetic reactance derived from short circuit analysis

In this paper, the characteristics analysis of a high-speed permanent magnet synchronous generator (PMSG) was performed considering saturation reactance. The equivalent circuit method (EMC) is a method for predicting performance in the design process of a generator. When using EMC, if the inductance of the equivalent circuit is not considering saturation, it is difficult to predict the performance of a generator accurately. Therefore, we applied a reactance that considered saturation to derive more accurate performance prediction through short-circuit analysis. The proposed method was verified using finite element method.

Design criteria and experiments considering the mechanical characteristics of high-speed permanent magnet synchronous generator of 8kW and 40krpm class

In this study, we designed, analyzed, and tested a permanent magnet synchronous generator by considering the mechanical characteristics of the rotor and the stator of an unmanned aerial vehicle (UAV) system operating at high-speed (40krpm). The size of the generator rotor was determined using the torque per rotor volume (TRV) analytical method. The designed generator uses a sleeve to prevent damage to the magnet during high-speed operation, and this sleeve must be designed to take into account the relationship between its mechanical characteristics and thickness, which affects electromagnetic behavior. Hence, the permanent magnet and the thickness of the sleeve and were selected by analyzing the rotor structure and considering the mechanical characteristics at the rated rotation speed. The characteristics of the designed generator were analyzed using the finite elements method and verified by experimental testing.

A Low THD Three-Level Rectifier For Gen-Set Applications

A low input current total harmonic distortion (THD) rectifier is presented, tailored around an open-end winding permanent magnet synchronous generator. Specifically, a six-level converter topology is obtained by connecting the generator stator winding to a three level T-type unidirectional rectifier on one side, and to an auxiliary two-level inverter on the other side. The T-type rectifier manages the entire active power stream and operates at the line frequency in order to minimize the switching power losses. The auxiliary inverter is instead driven by a standard PWM technique, being tasked to sinusoidally shape the input current and to actively balance the voltage across the dc-bus capacitors of the T-type rectifier. Such an inverter, being rated at a lower power and at a lower voltage than the T-type rectifier, can exploit low-cost power mosfet s. The proposed topology, featuring a very low input current THD, could well supplement in aircraft, portable or distributed generation applications, modern high-speed permanent magnet synchronous generators featuring a quite small stator impedance. Simulation and experimental results confirm the effectiveness of the proposed configuration.

Instantaneous power control of a high speed permanent magnet synchronous generator based on a sliding mode observer and a phase locked loop

ABSTRACTThis paper proposes an instantaneous power control method for high speed permanent magnet synchronous generators (PMSG), to realize the decoupled control of active power and reactive power, through vector control based on a sliding mode observer (SMO), and a phase locked loop (PLL). Consequently, the high speed PMSG has a high internal power factor, to ensure efficient operation. Vector control and accurate estimation of the instantaneous power require an accurate estimate of the rotor position. The SMO is able to estimate the back electromotive force (EMF). The rotor position and speed can be obtained using a combination of the PLL technique and the phase compensation method. This method has the advantages of robust operation, and being resistant to noise when estimating the position of the rotor. Using instantaneous power theory, the relationship between the output active power, reactive power, and stator current of the PMSG is deduced, and the power constraint condition is analysed for operation at the unit internal power factor. Finally, the accuracy of the rotor position detection, the instantaneous power detection, and the control methods are verified using simulations and experiments.

Minimum loss control of high-speed PMSG with variable speed operation

ABSTRACTBy analysing the loss model of high-speed permanent magnet synchronous generator (PMSG), the analytic formula of loss using quadrature–direct axis current and speed is established. It shows that the total loss is concave function with respect to d-axis current and speed so that the mathematical method of solving the extreme value can be applied and then the explicit expression of the two independent variables direct axis current and the speed at the minimum loss point can be achieved. Considering the effect of the maximum current limitation of the hardware circuit on the system speed operation mode, the minimum loss speed and direct current integrated control strategy are raised. The results show that compared with the traditional algorithm, the algorithm has obvious advantages, and the efficiency of the algorithm is improved by 16.91% compared with the traditional algorithm.

Micro-Generator Design for Smart Grid System (Comparative Study)

Abstract High Speed PM Generators driven by micro-turbines are widely used in Smart Grid System. So, this paper proposes comparative study among six classical, optimized and genetic analytical design cases for 400 kW output power at tip speed 200 m/s. These six design trials of High Speed Permanent Magnet Synchronous Generators (HSPMSGs) are: Classical Sizing; Unconstrained optimization for total losses and its minimization; Constrained optimized total mass with bounded constraints are introduced in the problem formulation. Then a genetic algorithm is formulated for obtaining maximum efficiency and minimizing machine size. In the second genetic problem formulation, we attempt to obtain minimum mass, the machine sizing that is constrained by the non-linear constraint function of machine losses. Finally, an optimum torque per ampere genetic sizing is predicted. All results are simulated with MATLAB, Optimization Toolbox and its Genetic Algorithm. Finally, six design examples comparisons are introduced with study of machines waveforms, THD and rotor losses.