Permanent Magnet Generator System Research Articles

Research on dual‐winding permanent magnet generator system with integrated dual‐channel controller

AbstractThis article presents a dual‐winding permanent magnet generator (PMG) system with integrated dual‐channel controller to meet the requirements of high power density, high reliability, and high output performance of aircraft electric power system. The dual‐winding of the PMG are designed to have the same phase spatially, with which the same rotor position can be applied in independent vector control. In addition, a dual‐channel controller is applied to control the two sets of windings, which achieves high‐performance control under normal state and fault‐tolerant control under fault state. The integrated dual‐channel controller integrates two sets of main power circuits into one controller and uses a main control unit, which simplifies the PMG system leading to reduction in the overall volume and weight. Reliability analysis of dual‐winding PMG system is proposed to be compared with that of the single‐winding PMG system. A dual‐winding cooperative control strategy and a fault‐tolerant control strategy are proposed to achieve high‐performance control of DC‐link voltage under normal condition and redundant functions under fault condition. As a result, the reliability of the PMG system is improved. The experimental results validate the effectiveness of the proposed PMG system and the control strategy.

A phase‐shift‐free synchronous reference frame filter‐based position sensorless control method for open‐winding permanent magnet generator system

An open-winding permanent magnet generator (OWPMG) system that offers features like fewer switching devices and high integration can be used in multi-input generator systems. To achieve high-accuracy position sensorless operation for the OWPMG system, this study investigates a phase-shift-free synchronous reference frame filter (SRFF-PSF) for use in the sliding mode observer (SMO) position sensorless algorithm. The proposed SRFF-PSF can completely restore the fundamental component of back-electromotive force (EMF) without phase shift and filter out the high-order harmonics owing to the following two improvements. First, the fundamental phase lag is eliminated by removing the low-pass filter between the back-EMF and the SRFF. Second, the error iteration of the output position angle is avoided by using the synchronous angle information from an additional phase locked loop module for the coordinate transformation of the SRFF. Based on the aforementioned improvements, the proposed method can effectively solve the phase shift problem in position estimation. The correctness and effectiveness of the method are verified by the experimental results.

Reference voltage vector based model predictive control for semicontrolled open‐winding flux‐switching permanent magnet generator system with a novel zero‐sequence current suppression strategy

Reference voltage vector based model predictive control for semicontrolled open‐winding flux‐switching permanent magnet generator system with a novel zero‐sequence current suppression strategy

Sliding mode control of permanent magnet generator system based on improved exponential rate reaching law

This study focuses on the improvement in the transient performance of DC-link voltage for a permanent magnet generator (PMG) system. Based on the vector control theory and double closed-loop control, the sliding mode control (SMC) method with the improved exponential rate reaching law (IERRL) is proposed in the voltage loop of the PMG system. The switching surface is designed with an integral term of state variable to suppress chattering and increase response speed. In addition, the IERRL that combines the concept of constant-proportional rate reaching law and exponential reaching law is proposed to further suppress chattering and eliminate steady-state tracking error of DC-link voltage. A detailed analysis of control law, system stability, reaching time, and chattering on switching surfaces are presented as well. The SMC method with IERRL improves the transient performance under sudden load changing occasion and eliminates the steady-state tracking error of DC-link voltage. Simulation and experimental results verify the effectiveness of the proposed method.

Dynamic Performance Improvement for Permanent Magnet Generator System Using Current Compensating Method With Two-Degrees-of-Freedom Control

This article proposes a two-degrees-of-freedom (TDOF) control with torque current compensating method (TCCM) to enhance the dynamic performance of permanent magnet generator (PMG) system when load changes. First, the mathematic model of PMG system with active front-end rectifier is introduced. Based on the system model, the proportional-integral controller of current loop is designed, and the TDOF controller designed with internal model control principle is derived for voltage loop control. There are two sets of parameters in the TDOF controller, one is used to regulate the system tracking performance when the command dc-link voltage changes, and the other is used to regulate the system antidisturbance capability when the electrical load changes. Second, the TCCM is proposed to further improve the system dynamic performance. The variation of torque current is applied to revise the command dc-link voltage, namely, the command dc-link voltage increases under loading occasion and decreases when unload occurs. The TCCM needs no additional hardware and is simple to implement. Simulation and experimental results verify the effectiveness of the proposed method.

Single-Phase Grid Connected Axial Flux Permanent Magnet Generator System with Harmonic Mitigation Functionality for Various Types of Nonlinear Loads

This paper proposes the implementation of a single-phase low cost grid connected axial flux permanent magnet (AFPM) generator system with harmonic mitigation functionality for various types of nonlinear loads. The design, construction and testing of the AFPM generator are given. The method of current reference calculation derived from a combination between power transfer and harmonic compensation for nonlinear loads is described. The synchronization with the grid does not require phase locked loop (PLL). It employs a simple technique based on a sinusoidal look-up table The whole converter system is implemented on a low cost dsPIC30F4011 microcontroller. The simulation and experimental results confirm the validity of the proposed system under various conditions.

A Controllable Power Distribution Strategy for Open Winding Hybrid Excitation Generator System

The open winding permanent magnet generator system is suitable for applications such as renewable energy power generation systems with multiple power sources, due to its high power density, relatively few power switches, and high degree of integration. However, for this system, it is difficult to quantitatively control the power distribution between different energy sources. In this paper, an open winding hybrid excitation generator system is presented, and for this system, a controllable power distribution strategy is investigated. In the proposed strategy, the excitation current is regulated according to the error in the current loop of the auxiliary energy source, which can achieve the regulation of the output power of the generator and finally realize the power quantitative control of the auxiliary energy source. Then, the topologies of the hybrid excitation machine are analyzed and chosen with emphasize on the influence of the flux regulation capability on the control capability of system power distribution. The experiments are carried out on a parallel hybrid excitation flux-switching (PHEFS) generator system, and the results verify the correctness and effectiveness of the proposed controllable power distribution strategy and the power distribution capability of the PHEFS generator.

Control Integrated Studies on High Speed Permanent Magnetic Generators System

The power converter control system has a great impact on the behavior of the high-speed permanent magnet generator system (HSPGS) due to the high operating frequency. In this paper, a 3-D modeling based on finite-element analysis directly coupled with a power converter control system is built in order to accurately evaluate generator performance. The influence of the control system current time harmonics on the 3-D flux distribution, the vector eddy current in rotor sleeve, and the iron loss of the machine are investigated. The analytical model is validated by experimental test results from a developed prototype of the HSPGS. The obtained results could provide a reference for the system-level design and investigation for the HSPGS in the further design.

A Matrix converter-interfaced PM Generator System with Active Filtering Capabilities

In this paper is presented a matrix converter- interfaced Permanent Magnet (PM) generator system which can provide shunt active filtering in addition to converting and transferring energy. The modulation technique is the simple and well-known indirect space vector modulation. The filtering current injected by the matrix converter and the input filter capacitor voltage are controlled by cascaded proportional control loops. Results showing that the matrix converter successfully provides active power filtering are given. Simulations also indicate that the filtering capability of the system depends on the generator side power factor. An explanation to this effect is given.

Optimization of Multibrid Permanent-Magnet Wind Generator Systems

This paper investigates the cost-effective ranges of gearbox ratios and power ratings of multibrid permanent-magnet (PM) wind generator systems by using a design optimization method. First, the analytical model of a multibrid wind turbine concept consisting of a single-stage gearbox and a three-phase radial-flux PM synchronous generator with a back-to-back power converter is presented. The design optimization is adopted with a genetic algorithm for minimizing generator system cost. To demonstrate the effectiveness of the developed electromagnetic design model, the optimization results of a 500-kW direct-drive PM generator and a 1.5-MW multibrid PM generator with various gear ratios are, respectively, compared with those from other methods. Then, the optimal design approach is further employed for a range from 750 kW up to 10 MW. The optimization results of PM generator systems including direct-drive and multibrid wind turbine configurations are obtained, and the suitable ranges of gear ratios for different power ratings are investigated. Finally, the detailed comparisons of the most cost-effective multibrid PM generator system and the optimized direct-drive PM generator system are also presented and discussed. The comparative results have shown that the multibrid wind turbine concept appears more cost-effective than the direct-drive concept.

Design optimization and site matching of direct-drive permanent magnet wind power generator systems

This paper investigates the possible site matching of the direct-drive wind turbine concepts based on the electromagnetic design optimization of permanent magnet (PM) generator systems. Firstly, the analytical models of a three-phase radial-flux PM generator with a back-to-back power converter are presented. The optimum design models of direct-drive PM wind generation system are developed with an improved genetic algorithm, and a 500-kW direct-drive PM generator for the minimal generator active material cost is compared to demonstrate the effectiveness of the design optimization. Forty-five PM generator systems, the combinations of five rated rotor speeds in the range of 10–30 rpm and nine power ratings from 100 kW to 10 MW, are optimally designed, respectively. The optimum results are compared graphically in terms of the generator design indexes. Next, according to the design principle of the maximum wind energy capture, the rotor diameter and the rated wind speed of a direct-drive wind turbine with the optimum PM generator are determined. The annual energy output (AEO) is also presented using the Weibull density function. Finally, the maximum AEO per cost (AEOPC) of the optimized wind generator systems is evaluated at eight potential sites with annual mean wind speeds in the range of 3–10 m/s, respectively. These results have shown the suitable designs for the optimum site matching of the investigated PM generator systems.

A study of generator system selection for large wind turbine generator system

AbstractThis paper focuses on selection of wind turbine generation systems that include generators, converters, and gears. We study three systems: a permanent magnet generator (PMG) system, a doubly‐fed generator (DFG) system, and a synchronous generator (SYG) system in terms of the system efficiencies and running costs. The system efficiencies and running costs are calculated by considering the relationship between wind power and wind conditions. According to these results, the one‐step gear PMG system is the best choice for a large wind turbine system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(1): 51–57, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20506

A Study of Generator System Selection for Large Wind Turbine Generator System

This paper focuses on selection of wind turbine generation systems that include generators, converters and gears. We study three systems: permanent magnet generator (PMG) system, doubly-fed generator (DFG) system and synchronous generator (SYG) system in terms of the system efficiencies and running costs. The system efficiencies and running costs are calculated with considering relation between wind power and wind condition. According to these results, the 1-step gear PMG system is the best choice to large wind turbine system.

Impact of load on winding inductances of permanent magnet generators with multiple damping circuits using energy perturbation

A computer-aided method for determining the impact of load on winding inductances and other machine parameters of permanent magnet generators with multiple damping circuits is presented. The method is general in nature so that it can be applied to detailed computer-aided design processes of permanent magnet generator systems. The method is based on use of the abc frame of reference for development of the necessary state equations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>