Permanent Magnet Synchronous Generator System Research Articles

Design of a transverse-flux permanent-magnet linear generator and controller for use with a free-piston stirling engine

Transverse-flux with high efficiency has been applied in Stirling engine and permanent magnet synchronous linear generator system, however it is restricted for large application because of low and complex process. A novel type of cylindrical, non-overlapping, transverse-flux, and permanent-magnet linear motor(TFPLM) is investigated, furthermore, a high power factor and less process complexity structure research is developed. The impact of magnetic leakage factor on power factor is discussed, by using the Finite Element Analysis(FEA) model of stirling engine and TFPLM, an optimization method for electro-magnetic design of TFPLM is proposed based on magnetic leakage factor. The relation between power factor and structure parameter is investigated, and a structure parameter optimization method is proposed taking power factor maximum as a goal. At last, the test bench is founded, starting experimental and generating experimental are performed, and a good agreement of simulation and experimental is achieved. The power factor is improved and the process complexity is decreased. This research provides the instruction to design high-power factor permanent-magnet linear generator.

Verification of Parametric Average-Value Model of Thyristor-Controlled Rectifier Systems for Variable-Frequency Wind Generation Systems

Line-commutated thyristor-controlled rectifiers are often used in many industrial and renewable energy applications where controllable dc voltage is required. The derivation of accurate dynamic average-value models for thyristor-controlled systems is challenging. The recently proposed parametric average value modeling (PAVM) avoids the discrete switching states of the converters and results in computationally efficient models that are suitable for system level studies. This paper extends the PAVM recently developed for synchronous-machine-fed thyristor-controlled-rectifier systems to a permanent magnet synchronous machine wind generation system where the operation in variable speed and frequency is required.

Current Zero-Crossing Duration Reduction of a Semicontrolled Open-Winding PMSG System Based on Third Harmonic Current Injection

The open-winding permanent-magnet synchronous generator (PMSG) fed by a semicontrolled converter is a promising configuration due to lower expense, simplified driving circuit, and reliable operation capability. When supplied by a common dc bus, the open-winding PMSG system can be more simplified. Because the voltage output by the diode converter is decided by the three-phase current polarity, the available voltage vector modulation range of the voltage source converter is limited. As a result, the current zero-crossing duration behavior is determined by the power factor angle, which will lead to zero-crossing voltage pulse disturbance, serious electromagnetic interference, and unexpected diode switching loss. This paper aims to reduce the current zero-crossing duration by injecting the third harmonic current into the zero-sequence current. A proportional resonant regulator is proposed to control the zero-sequence current. Finally, the proposed method is validated in a 1-kW semicontrolled open-winding PMSG experimental system.

A Novel Maximum Power Tracking by VSAS approach for Permanent Magnet Direct Drive WECS

This paper presents control schema of a permanent magnet synchronous generator (PMSG) system with two controllers for generator side and grid side converters in a variable speed wind turbine (VSWT) application. In generator side converter, the most efficient algorithms designed to track the maximum power point (MPP) for catching the maximum wind power is reviewed. For this approach we then design a new maximum power point tracking (MPPT) algorithm using the Variable Structure Automatic Systems approach (VSAS).The proposed approach leads efficient algorithms as shown in this paper by the analysis and simulations. The obtained results show clearly the superiority of the Modified Enhanced Perturb and Observe (MEPO) technique. Using this MPPT method the generated power by the turbine is considered to be, in terms of power control, an auxiliary source feeding a grid. In the grid side converter, active and reactive power control has been achieved by controlling d-axis and q-axis grid current components respectively. The simulation results show the efficiency and reliability of the control strategy proposed in this paper.

Control strategies for variable-speed permanent magnet synchronous generator systems

Purpose – The purpose of this paper is to focus on various control strategies for permanent magnet synchronous generator (PMSG) systems, in order to stabilize the dc link output voltage over a wide operation speed range. Design/methodology/approach – Two control methods, namely, the flux regulation control (FRC) which adjusts the stator flux linkage and then indirectly stabilize the dc link voltage, and the direct voltage control (DVC) which directly stabilize the dc link voltage by regulating the power angle, are proposed in this paper. Both methods can be realized by either approach of the conventional space vector pulse width modulation (SVPWM) or the proposed single voltage vector modulation (SVVM). Findings – The FRC can optimize the field in the PMSG, however, the realization is complicated. The DVC need not estimate and regulate the stator flux linkage, hence is easy to implement. On the other hand, the SVPWM can provide smooth armature current and dc link voltage, while the SVVM applies only one voltage vector during each control cycle, hence, is simple to realize and requires the minimum switching on the PWM rectifier. All cross-combinations between the two control methods and the two realization approaches work well. Originality/value – The proposed FRC and DVC methods are simpler than the conventional field oriented control, while the proposed SVVM is a novel and efficient approach to generate the PWM status. Optimal cross-combination, either of SVPWM-FRC, SVVM-FRC, SVPWM-DVC and SVVM-DVC, can be chosen to satisfy the system characters and requirements.

Enhanced Control for a Direct-driven Permanent Synchronous Generator Wind-power Generation System with Flywheel Energy Storage Unit Under Unbalanced Grid Fault

—This article presents an enhanced control strategy for a direct-driven permanent synchronous generator based wind-power generation system with a flywheel energy storage unit. The behaviors of the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit under unbalanced grid fault conditions are investigated. Three control targets for the grid-side converter during network unbalance conditions are identified, including eliminating the oscillations in the total active power or reactive power or no negative-sequence current injecting into the grid. Meanwhile, the DC-link voltage oscillations can be effectively suppressed during the unbalanced grid fault by controlling the flywheel energy storage unit. Furthermore, a proportional–integral-resonant controller is designed for the flywheel motor to eliminate the oscillations in the DC-link voltage. Finally, the proposed coordinated control strategy for the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit has been validated by the simulation results of a 1-MW direct-driven permanent magnet synchronous generator wind power generation system with a flywheel energy storage unit under unbalanced grid fault.

Machine design and control strategy for wide-speed-range PMSG systems

Purpose – The purpose of this paper is to focus on the machine design and control strategy of the permanent magnet synchronous generator (PMSG) system, especially utilized in variable speed applications, in order to stabilize the output voltage on the dc link over a wide speed range. Design/methodology/approach – Different ac/dc power converter topologies are comparatively studied, each with an accordingly designed PMSG, so as to investigate the influence of the armature winding inductance as well as the relationship between the PMSG and power converter topologies. Findings – Pulse width modulation (PWM) rectifier is preferable for the said application due to its good performance and controllability. Moreover, by employing the PWM rectifier, relatively large inductance of the PMSG is considered for both short-circuit current reduction and field regulation. Originality/value – Field-regulating control is realized with a space vector PWM (SVPWM) rectifier, which can weaken the PMSG magnetic field during high-speed operation, while even properly enhance the field at low speed, ensuring a small change of the PMSG output voltage and a stable dc voltage.

Investigation of Open-Winding PMSG System With the Integration of Fully Controlled and Uncontrolled Converter

An open-winding permanent-magnet synchronous generator (PMSG) system with the integration of fully controlled and uncontrolled converter is investigated in this paper, in which half the amount of controllable power switches are needed compared with the conventional open winding system fed by two voltage source converters. The voltage space vector of open winding PMSG is modulated by controlled converter, which will be integrated with the voltage vector by uncontrolled converter to implement the operation of open winding PMSG. In order to analyze and compare the operation capability on the different dc voltage ratios, the available modulation range of the open winding PMSG is analyzed in detail. Moreover, unity power factor control is proposed as the optimized control method to achieve the maximum modulation index. Finally, a 1-kW experimental setup is built to validate the theoretical investigation on the open winding PMSG system.

SMR 회로를 이용한 소형풍력발전 시스템의 센서리스 퍼지 MPPT제어

This paper proposes a low-cost switched-mode rectifier (SMR) for a small-scale wind turbine with a permanent magnet synchronous generator (PMSG) system. Also, a sensorless Fuzzy MPPT control is realized by the proposed system. In the PMSG system with the SMR, the synchronous impedance can be replaced as the input inductor of a boost converter. Moreover, the sensorless MPPT control using the Fuzzy technique is carried out by the duty-ratio regulation of the SMR. The relation between the generating power and the duty-ratio is ruled by the chain rule. The wind turbine model is implemented by the squirrel cage induction motor and generated the variable torque when the generator speed is varied. To verify the performance of the proposed system, simulation and experimental results are executed.

Adaptive Controller for Drive System PMSG in Wind Turbine

This paper proposes adaptive Maximum Power Point Tracking (MPPT) controller for Permanent Magnet Synchronous Generator (PMSG) wind turbine and direct power control for grid side inverter for transformer less integration of wind energy. PMSG wind turbine with two back to back voltage source converters are considered more efficient, used to make real and reactive power control. The optimal control strategy has introduced for integrated control of PMSG Maximum Power Extraction, DC link voltage control and grid voltage support controls. Simulation model using MATLAB Simulink has developed to investigate the performance of proposed control techniques for PMSG wind turbine steady and variable wind conditions. This paper shows that the direct driven grid connected PMSG system has excellent performances and confirms the feasibility of the proposed techniques. While the wind turbine market continues to be dominated by conventional gear-driven wind turbine systems, the direct drive is attracting attention. PM machines are more attractive and superior with higher efficiency and energy yield, higher reliability, and power-to-weight ratio compared with electricity-excited machines.

A Fuzzy Controlled Scheme for an Isolated Hybrid MPPT-Photovoltaic Diesel-PMSG System

In this paper, a controlled scheme for a hybrid photovoltaic-diesel–PMSG system is presented. In order to feed a considered load according to power demand, both or one of two generators can be used; the first one is an MPPT fuzzy controlled buck-photovoltaic panel, the second is a permanent magnet synchronous generator (PMSG) driven by a diesel motor. In order to perform the system, a fuzzy controlled supervisor realizes the adequate choose between the generators. So that, in the first case, to feed the considered isolated load when the MPPT fuzzy controlled photovoltaic panel power is sufficient, the load receives the required input power only from the photovoltaic panel through a boost converter and a DC bus. In the other case, when the photovoltaic panel is insufficient, the PMSG is used; a diode rectifier and an LC-LC filter are associated. Thus, in this new case, the considered load is fed by the photovoltaic panel and the PMSG simultaneously. A significant simulation work was presented so as to take out the important results. Different results are presented and discussed in order to justify the important performances of the system. They show clearly how the proposed methodology is an efficient hybrid photovoltaic diesel control procedure

Dynamic control for permanent magnet synchronous generator system using novel modified recurrent wavelet neural network

Because permanent magnet synchronous generator (PMSG) system driven by permanent magnet synchronous motor (PMSM) based on wind turbine emulator (WTE) is a nonlinear and time-varying system with high complication, an accurate dynamic model of the PMSG system directly driven by WTE is difficult to establish for the linear controller design. In order to conquer this difficulty and improve the robustness of dynamic system, the PMSG system controlled by the online-tuned parameters of the novel modified recurrent wavelet neural network (NN)-controlled system is proposed to control output voltages and powers of controllable rectifier and inverter in this study. First, a closed-loop PMSM-driven system based on WTE is designed for driving the PMSG system to generate output power. Second, the rotor speeds of the PMSG, the voltages, and currents of the two power converters are detected simultaneously to yield maximum power output. In addition, two sets of the online-tuned parameters of the modified recurrent wavelet NN controllers in the controllable rectifier and inverter are developed for the voltage-regulating controllers in order to improve output performance. Finally, some experimental results are verified to show the effectiveness of the proposed novel modified recurrent wavelet NN controller for the power output of the PMSG system driven by WTE.

Zero Sequence Current Suppression Strategy of Open Winding PMSG System with Common DC Bus based on Zero Vector Redistribution

The open-winding configuration with a common dc bus provides a zero-sequence current loop which allows the zero-sequence current flowing. With the application in permanent magnet synchronous generator (PMSG) systems, the existing zero-sequence current is inevitably caused by the common mode voltage generated by pulsewidth modulation (PWM) techniques and the third back EMF by the inherent flux harmonic component. With the mathematical modeling analysis, the zero-sequence equivalent circuit based on the PMSG system is proposed. Meanwhile, a zero-sequence current suppression controller is designed. In this paper, a zero vector redistribution PWM technique is proposed. With this technique, the dwell times of zero vectors (000) and (111) for both converters are determined. Meanwhile, it gives the zero-sequence component overmodulation analysis. Both the control method and improved PWM technique are implemented in a 1-kW open-winding PMSG experimental setup, and the experimental results are discussed.

Recurrent wavelet neural network control of a PMSG system based on a PMSM wind turbine emulator

A recurrent wavelet neural network (NN)-controlled 3-phase permanent magnet synchronous generator system (PMSG), which is direct-driven by a permanent magnet synchronous motor (PMSM) based on a wind turbine emulator, is proposed to control the output values of a rectifier (or AC to DC power converter) and inverter (or DC to AC power converter) in this study. First, a closed-loop PMSM drive control based on a wind turbine emulator is designed to generate the maximum power for the PM synchronous generator (PMSG) system according to different wind speeds. Next, the rotor speed of the PMSG, the DC bus voltage, and the current of the power converter are detected simultaneously to yield a better power output of the converter through DC bus power control. Because the PMSG system is a nonlinear and time-varying dynamic system, one online-trained recurrent wavelet NN controller is developed for the tracking controller of the DC bus power to improve the control performance in the output end of the rectifier. Additionally, another online-trained recurrent wavelet NN controller is also developed for tracking the controller of the AC power to improve the control performance in the output end of the inverter. Finally, some experimental results are verified to show the effectiveness of the proposed recurrent wavelet NN-controlled PMSG system direct-driven by a PMSM based on a wind turbine emulator.

A MPPT Strategy for Wind Power PMSG System with Full Power Converter

The direct-drive permanent-magnet synchronous generator (PMSG) system with full power converter can achieve wind maximum power point tracking (MPPT) in wide range variation of wind-speed. In this paper an operating characteristic of PMSG is investigated, a MPPT strategy based on hill climbing method for PMSG are present. Simulation and experimental results show that the controllers can extract maximum wind power in good dynamic performance.

Performance Enhancement of PMSG Systems with Control of Generator-side Converter Using d-axis Stator Current Controller

This paper presents a performance enhancement of a permanent magnet synchronous generator (PMSG) system with control of generator-side converter for a wind turbine application. This method uses zero d- axis stator current control to minimize winding losses of the generator. The electromagnetic torque of the generator is correlated with the magnitude of the qaxis stator current, while the daxis stator current is regulated at zero, the control scheme decouples the dq-axis stator current control through a vector con- trol for the generator-side converter. This paper also presents mathematical analysis of the active power and stator power factor, and the maximum power point tracking (MPPT) operation. Simulation re- sults are provided to guarantee the proposed control scheme, in which the performance enhancement and eciency are evaluated.

Recurrent modified Elman neural network control of permanent magnet synchronous generator system based on wind turbine emulator

The two recurrent modified Elman neural networks (NNs) controlled permanent magnet (PM) synchronous generator system based on wind turbine emulator is proposed to regulate output voltages of rectifier and inverter in this study. First, the wind turbine emulator, which adopts a closed-loop PM synchronous servo motor drive system to act as prime machine, is designed to drive the PM synchronous generator system to yield the maximum power at different wind speeds. Then, the rotor speed of the PM synchronous generator, the DC bus voltage, and current of the rectifier are detected simultaneously to yield maximum DC power of the rectifier through DC bus power control. Moreover, one online training recurrent modified Elman NN controller is developed to regulate DC bus voltage in the output end of rectifier and another online training recurrent modified Elman NN controller is developed to regulate AC power in the output end of inverter in order to improve the control performance. Finally, some experimental results are verified to show the effectiveness of the proposed recurrent modified Elman NN controlled PM synchronous generator system based on wind turbine emulator.

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.

Recurrent modified Elman neural network control of PM synchronous generator system using wind turbine emulator of PM synchronous servo motor drive

The recurrent modified Elman neural network (NN) controlled a permanent magnet (PM) synchronous generator system, which is driven by wind turbine emulator of a PM synchronous motor servo drive, is developed to regulate output voltage of rectifier (or AC to DC power converter) and inverter (or DC to AC power converter) in this study. First, the wind turbine emulator of a closed loop PM synchronous motor servo drive is designed to produce the maximum power for the PM synchronous generator system. Then, the rotor speed of the PM synchronous generator, the output DC bus voltage and current of the rectifier are detected simultaneously to yield maximum power output of the rectifier through DC bus power control. Because the PM synchronous generator system is a nonlinear and time varying dynamic system, the online training recurrent modified Elman NN control system is developed to regulate DC bus voltage of the rectifier and AC line voltage of the inverter in order to improve the control performance. Furthermore, the online training recurrent modified Elman NN control system with the variable learning rate is derived based on Lyapunov stability theorem, so that the stability of the system can be guaranteed. Finally, some experimental results are verified to show the effectiveness of the proposed recurrent modified Elman NN controlled PM synchronous generator system.

Voltage Control of PM Synchronous Motor Driven PM Synchronous Generator System Using Recurrent Wavelet Neural Network Controller

In this paper the two novel recurrent wavelet neural network (RWNN) controllers are proposed for controlling outputdirect current (DC) voltage of the rectifier and output alternate current (AC) voltage of the inverter. The output powerof the rectifier and the inverter is provided by three-phase permanent magnet synchronous generator (PMSG) systemdirectly-driven by permanent magnet synchronous motor (PMSM). Firstly, the field-oriented mechanism isimplemented for controlling output of the PMSG system. Then, one RWNN controller is developed for controllingrectifier to convert AC voltage into DC link voltage and the other RWNN controller is implemented for controllinginverter to convert DC link voltage into AC line voltage. Moreover, two online trained RWNNs using backpropagationlearning algorithms are developed for regulating both the DC link voltage of the rectifier and the AC line voltage of theinverter. Finally, the effectiveness and advantages of the proposed two RWNN controllers are demonstrated incomparison with the two PI controllers from some experimental results.