Permanent Synchronous Machine Research Articles

Rotor-Flux Vector Based Observer of Interior Permanent Synchronous Machine

The sensorless control system of the interior permanent magnet machine (IPMSM) is considered in this paper. The control system is based on classical linear controllers. In IPMSM, there occurs non-sinusoidal distribution of rotor flux together with the slot harmonics, these are treated as control system disturbances. In this case, the classical observer structure in the (d-q) is unstable for the low range of rotor speed resulting in disturbances. This negative effect can be minimized by using the observer structure which is based on the rotor flux vector in (α-β) stationary frame together with the classical rotor speed and position law of estimation. The performance of the observer structure is validated by simulation and experimental results in the sensorless control system with field-oriented control.

Artificial Intelligence Approach for the Control of SPMSG Based Grid Connected WECS

In India, power plant requirement is rapidly increasing as non-conventional sources are in current need. Government financial aid plays important role for generator plant execution because of its tedious procedure. If the utilization of wind power production has to be doubled, then machines, turbines and converters are essential in two numbers. The research work includes parallel connection of two machines using star-delta-star transformer fashion resulting in six-phase permanent synchronous machine. This arrangement is more economical as the number of converters are reduced thereby increasing the efficiency by minimizing the switching losses. Initially rectifier setup is used wherein high frequency AC is converted to low frequency and maximum power point tracking is done with the aid of a converter. It is DC-DC conversion by decoupled DQ strategy. Later, it is again converted back to three phase AC so as to synchronize it to the grid. The system response is analysed by conventional PI controller by reducing the noise in the real & reactive power generation. Further, ANFIS-PI controller is implemented to improve the response of PI controller which is much essential for wind power generation. The MATLAB simulated results of PI controller system response and ANFIS-PI controller is presented in this paper.

Efficient Maximum Torque Per Ampere (MTPA) Control of Interior PMSM Using Sparse Bayesian Based Offline Data-Driven Model With Online Magnet Temperature Compensation

The maximum torque per ampere (MTPA) is popular control strategy for interior permanent synchronous machines (PMSMs) and MTPA point is dependent on the magnetic saturation and magnet temperature. This paper proposes a novel MTPA control method combining offline model and online compensation model for interior PMSM control. In the proposed approach, an offline sparse Bayesian based data driven model is derived from the machine equations to consider magnetic saturation, and an online compensation model is proposed to compensate the magnet temperature. The MTPA point can be derived by combining both the offline and online models, in which both saturation and temperature effects are considered to ensure the performance of MTPA point tracking. Compared with the offline methods, the proposed approach employs the sparse vector to represent the MTPA model with less computation and memory consumption and considers the temperature effect with better robustness. Compared with the online methods, the proposed approach only compensates the offline model with online temperature effect, which is less sensitive to noise and uncertainties and involves less computation. The proposed approach is validated with comparisons and experiments on a laboratory interior PMSM drives.

Robust adaptive direct speed control of PMSG-based airborne wind energy system using FCS-MPC method

Electricity generation using airborne wind energy system (AWES) tends to be more efficient than that of conventional wind turbines due to their ability at extracting higher speeds from wind at higher altitudes by the tethered kite generator system (TKGS). The speed regulation of a permanent synchronous machine (PMSM) attached to a kite to maximize harvested power from wind is the topic of the present research. To track the optimal speed produced by TKGS, a finite-control-set model predictive control (FCS-MPC) with a new cost function is directly employed to generate appropriate gate signals for a 3-level neutral point clamped (3-L NPC) inverter that drives a PMSM. A novel adaptive algorithm is also provided for adjusting the weight coefficients of the cost function to improve the system’s performance across a wider range of change in the operating conditions. Moreover, a terminal sliding mode disturbance observer (TSMDO) is designed to estimate the load torque. A terminal sliding mode speed controller (TSMSC) is also used to produce the current reference for the optimizing algorithm in FCS-MPC. The proposed control scheme eliminates the need for a cascade structure while significantly reduces current deformation and torque oscillations. Additionally, the controller operates as fast as a traditional direct speed controller without the use of a cascade structure and is more robust against parameter uncertainties. To illustrate the success of the suggested controller, the results of simulations are presented in MATLAB/SIMULINK® software. The performance of the proposed technique is evaluated in three situations which simulates a grid-connected PMSM fed by a back to back 3-L NPC. In the first scenario, it is demonstrated that the suggested technique performs well when the system’s operational conditions vary. The performance of the adaptive tuning mechanism of the cost function weight factors is investigated in the second scenario, which takes into account model parameter uncertainty. The impacts of the disturbance observer (DO) on the system performance are explored in the final scenario, and it is discovered that the disturbance observer may increase the speed response and DC link voltage tracking performance. All of the simulation results show that the new technique outperformed the traditional FSC-MPC.

Junction Temperature Control System to Increase the Lifetime of IGBT-Power-Modules in Synchronous Motor Drives Without Affecting Torque and Speed

Load changes of electrical machines driven by inverters cause temperature swings of the semiconductor devices in IGBT modules of the inverters. These temperature swings lead to mechanical strain in the different material layers of the IGBT-power-modules and limit the numbers of cycles to failure and therefore reduce the lifetime of the IGBTs. This paper presents a temperature control system which is paralleled to the standard torque control system. It aims to reduce the magnitude of temperature swings of the semiconductor devices of IGBT modules caused by load changes of an interior permanent magnet synchronous machine. The principle method is, to increase the temperature of the semiconductor devices of the IGBT-modules by creating higher power losses during low load conditions of the machine without affecting torque and speed. This reduces the magnitude of the load induced temperature swings of the semiconductor devices of IGBT-modules and increases its lifetime at the cost of increased power losses. Three variables have been identified that influence the power losses in inverter modules without necessarily affecting the output power of the permanent synchronous machine. These variables are switching frequency of the inverter, length of the clamping area when a discontinuous modulation is applied and the reactive component of the inverter current. The influence of each variable which regards to the losses in the IGBT-power-modules is explained and the related control methodology is described. The analytic results are verified by experimental results obtained from a test set up.

Analysis and Design of a Delta-Type Interior Permanent Magnet Synchronous Generator by Using an Analytic Method

The analytic analysis of delta-type interior permanent synchronous machines is difficult due to the absence of a useful analytic method, especially considering the high magnetic saturation effect of the machine. Hence, the nonlinear magnetic equivalent circuit (MEC) method, which considers the severe magnetic saturation of the iron core, is proposed in this paper. With the proposed nonlinear MEC method, the characteristics of the delta-type interior permanent magnet synchronous generator (IPMSG) are precisely calculated and the computational burden is remarkably reduced. The proposed MEC method is validated by comparing the calculated data with the experimental results.

A Novel Approach for 2-D Electromagnetic Field Analysis of Surface Mounted Permanent Magnet Synchronous Motor Taking Into Account Axial End Leakage Flux

This paper proposes a novel approach for electromagnetic field analysis of surface-mounted permanent synchronous machines taking into account axial end leakage flux. In order to calculate the axial end leakage flux using the 2-D finite-element analysis (FEA), the leakage magnetic flux in the axial direction is reflected to the 2-D model by applying the permeability factor into the slot area. The permeability factor is derived by the equivalent magnetic circuit method. At this time, the permeability factor is calculated by considering the main leakage path in the slot and the leakage path in the axial direction of air region. The effectiveness of the proposed method is verified by comparing the results of the proposed method with the experimental results as well as the conventional 2-D FEA results and the 3-D FEA results.

Direct Drive Permanent Magnet Synchronous Wind Generator Maximum Power Tracking Control

Direct drive permanent magnet synchronous generator have the advantages of direct drive, simple structure, high efficiency and so on, in which make it become one of mainstream models within MW wind turbine presently. Making the direct drive permanent magnet wind power generation system as the main research object, based on the principle of the operating characteristics of direct drive permanent magnet synchronous wind generator ( DDPMG ), establish mathematical model of the whole system including wind velocity, wind turbine, direct drive permanent magnet synchronous generator and machine side converter, Appling the method of stator flux orientation to make the study of vector control strategy, to build the simulation model of direct drive permanent magnet synchronous generator system with Matlab and simulate when wind speed changes by step, the results validate the reasonableness of the model and the correctness and feasibility of the control strategy.

Simulation of Magnetization Errors Using Conformal Mapping Field Computations

Due to their production and magnetization process, rare earth magnets, e.g. NdFeB, exhibit deviations from the targeted ideal remanent magnetic flux-density. As a consequence, the calculation of cogging torque, load torque and force computations of a permanent-magnet synchronous machine by means of finite-element analysis are at best in fair agreement to measurements, since the mentioned variations of the magnet material are not covered by standard simulation models. Actual solutions to consider these variations in the simulation of a permanent-magnet synchronous machine consist either in a full-factorial Monte-Carlo simulation or advanced stochastic analysis techniques such as the creation of polynomial-chaos meta-models. Even meta-model techniques result in an exponential growth of repetitive finite element simulations for a rise in the used polynomial's degree or an increment of the input variables. In order to reduce computation time, this paper unveils a methodology to build the magnet rotor field distribution with consideration of magnet faults semianalytically for calculating arbitrary machine operation points. For this purpose a conformal mapping approach is extended to be applicable to stochastic variations. It is shown, how the conformal mapping assumption of symmetrical field conditions can be overcome. As a result, the proposed approach is applied to the calculation of cogging torques for stochastic varying magnetizations in a permanent synchronous machine.

Design and Performance Analysis of an Integrated Starter-Alternator for Hybrid Electric Vehicles

In automotive applications, the requirements for the electrical machines are about performance and reliability - the permanent magnet synchronous machines ensure these requirements are fulfilled. The approach of the present paper is to analyze the permanent synchronous machines suited for the integrated starter-alternator (ISA) applications. The study design requires some analytical, followed by a numerical analysis and also a finite element method in order to achieve the performances of the machine. The operation modes of an ISA system and the constraints for an electric machine acting as an ISA are detailed. Finally a model for a ISA hybrid vehicle, developed in AMESim is presented and the results of a simulated drive cycle are presented.

Thrust Optimization of a Flux-Switching Linear Synchronous Machine With Yokeless Translator

Linear permanent magnet machines have been increasingly used in several applications that require high reliability and good dynamic characteristics. In this paper, a novel double-sided design of a 3φ permanent magnet flux-switching linear synchronous machine (FSLSM) with a yokeless translator is proposed. It is found that the proposed design can achieve more than 50% higher thrust than a conventional FSLSM and excellent linearity even under high excitation currents. Optimization of the proposed machine is performed using individual parameter optimization and is compared with results from global optimization using genetic algorithm (GA). Force analysis of the proposed design is performed to establish the mechanical integrity of the design. The proposed FSLSM is most suitable for long-stroke applications and intermittent oscillatory type applications.

Robust Multilevel Optimization of PMSM Using Design for Six Sigma

In this paper, a robust optimization method based on design for six sigma (DFSS) is combined to the optimization of a surface mounted permanent synchronous machine (PMSM) by using multilevel genetic algorithm (MLGA). First, MLGA and DFSS are introduced in the robust optimization. Second, by taking into account the tolerances of the motor products, important input parameters could be varied with six sigma distribution and Monte Carlo simulation (MCS) method is used to reduce the calculation cost. Third, to verify the new algorithm, the presented algorithm is applied to the optimization of a PMSM. The results compared with those of traditional GA and MLGA and the discussion of the robust optimization combined with MLGA are presented.

Speed Control of a Permanent Magnet Synchronous Machine Powered by an Inverter Voltage Moment Approach

In this paper, the method of moments is presented in order to synthesize controllers for current and speed of a Magnet Permanent Synchronous Machine (PMSM). The controller’s dynamics are chosen in respect with the time domain constraints, which have equality relationships between the moments of the closed-loop system and those of the reference model. The Linear Matrix Inequality (LMI) formalism is used for the controller synthesis. The proposed controller is applied for the speed tracking of a PMSM to illustrate the performances of the method.

A NEW FAST METHOD OF PROFILE AND WAVEFRONT REDUCTION FOR CYLINDRICAL STRUCTURES IN FINITE ELEMENTS METHOD ANALYSIS

We present a new accurate node's renumbering method for minimizing the proflle of stifiness matrix arising in flnite elements problems. This method is suitable for cylindrical structures like electrical rotating machines and is especially intended for movement consideration by the moving band method. The structure is divided into sectors classifled in a special way. The nodes contained in each sector are classifled according to their radius value in regressing order. We show that the performances of the method are better than the most popular ones proposed in the literature. Application for a permanent magnet synchronous machine is presented. Application for flnite elements analysis of a permanent synchronous machine in motion is achieved.

Battery Recharging Issue for a Two‐Power‐Level Flywheel System

A novel battery recharging system for an all‐electric driveline comprising a flywheel with a permanent magnet double wound synchronous machine (motor/generator) is presented. The double winding enables two voltage levels and two different power levels. This topology supersedes other all‐electric drivelines. The battery operates in a low‐power regime supplying the average power whereas the flywheel delivers and absorbs power peaks, which are up to a higher order of magnitude. The topology presents new challenges for the power conversion system, which is the focus of this investigation. The main challenge is the control of the power flow to the battery when the vehicle is parked despite the decay of the flywheel machine voltage; which is dependent on its charge state, that is, rotational speed. The design and simulation of an unidirectional DC/DC buck/boost converter for a variable rotational speed flywheel is presented. Conventional power electronic converters are used in a new application, which can maintain a constant current or voltage on the battery side. Successful PI current control has been implemented and simulated, together with the complete closed loop system.

Performance improvement of permanent magnet machines by modular poles

Modular permanent magnet poles have recently been proposed to enhance the performance of permanent magnet machines and improve the exploitation of used magnet materials. An optimisation method for these poles is proposed for use in linear permanent magnet synchronous machines. The main objective of the optimisation is to select proper dimensions and material properties of modular permanent magnet poles to enhance the machine developed thrust. The optimisation is carried out based on a mathematical model of the machine obtained analytically. In particular, the developed thrust of linear permanent synchronous machines with modular poles is given by the model. Genetic algorithm is then employed to optimise pole parameters where the ratio of thrust ripples to average thrust is chosen as an objective function. Extensive investigations carried out by analytical and finite element methods confirm that substantial lower thrust ripples are produced with almost the same average thrust.

Development of PMSM Drives for Hybrid Electric Car Applications

Permanent synchronous electric machine (PMSM) drives for the FAW hybrid electric car is investigated in this paper. The power system configuration of the FAW is introduced. The influences of the stator winding turn and the permanent magnet width on the torque-speed characteristic are analyzed. The torque-speed characteristic that the specification required is obtained by proper choice of these two parameters. The torque ripple and the harmonic contents of the electromotive force (EMF) are decreased by rotor shape optimizing to improve the traction performance and the supply quality. The rotor shape is optimized by the offset arc method. The analysis is verified by the sample PMSM experimentation

Dual-Inverter Control Strategy for High-Speed Operation of EV Induction Motors

An integrated starter/alternator (ISA) is normally designed to have high pole structure (10-14 poles) for high starting torque. However, its back electromotive force (EMF) at the peak revolutions per minute should be less than its battery voltage for the power flow control. For example, the back-EMF of a 12-pole ISA should be 42 V at 6000 r/min. These types of conflicting requirements lead to a nonclassical motor design that has extremely large field-weakening range (8:1/spl sim/10:1). In this paper, we are considering the use of an induction machine instead of a permanent synchronous machine. As an idea for solving the voltage limit problem, two inverters are utilized with an objective of sharing the required voltage. The secondary inverter only takes care of the reactive voltage component that grows very fast in high-speed operation. Therefore, an extra voltage source is not required for the secondary inverter. Only a capacitor bank suffices for the secondary inverter.

Controller design for applying field-oriented control to the permanent magnet synchronous machine

Abstract Field-oriented control (FOC) has become widely used as a method of enabling the permanent synchronous machine (PMSM) to realize a dynamic performance equal or superior to that of the DC machine. This paper explains the concept of FOC with the aid of the block diagram or functional form of the PMSM's mathematical equations, thereby providing insight into the internal decoupling process that occurs within the machine. It then presents a design process for a high performance field-oriented controlled PMSM speed control system.