Permanent Magnet Synchronous Generator System Research Articles

Aggregation Equivalence Method for Direct-Drive Wind Farms Based on the Excitation–Response Relationship

The grid interconnections for direct-drive wind farms have triggered multiple new sub-synchronous oscillation events, which can prevent the power system from operating safely and stably. However, the excessively high order of the detailed model for large-scale wind farms with multiple direct-drive permanent magnet synchronous generators (PMSGs) connected to power systems poses a challenge when investigating small disturbance stability and instability mechanisms. This study establishes a model of the grid-connected PMSG system based on the voltage/power excitation–response relationship to describe the dynamic characteristics of the port of the PMSG, and the analysis of active and reactive response characteristics of PMSG lays the foundation for model simplification. Based on the unit model, a direct-drive wind farm aggregation equivalence method based on the excitation–response relationship is proposed. The equivalent model obtained by this method is suitable for the small disturbance stability analysis of direct-drive wind farms grid connected system, with good accuracy. The simulation verified the effectiveness of the aggregation model.

A new passive‐based active disturbance rejection control for PMSG system with saturation constraints

AbstractThe disturbance in wind energy conversion system has a serious negative impact on the maximum power tracking performance of the system, and the saturation constraint problem also seriously restricts the stability of the control system. Therefore, a novel model compensation passive‐based active disturbance rejection control strategy is proposed to suppress the disturbance and saturation constraints, thus improving the tracking performance of the permanent magnet synchronous generator system in this paper. Taking advantage of the fact that active disturbance rejection control technology can estimate and compensate for the disturbances of the system in real time, a model compensation active disturbance rejection control method is proposed to make the system more robust to the changes in its own parameters and external disturbance. At the same time, the control input signal of the controller is given. A model compensation passive‐based active disturbance rejection controller is designed by using the passive control method, and the nonlinear sector method is introduced to solve the saturation constraint problem of the system. Simulation results show that the control strategy can effectively reduce overshoot, improve the system's response speed, have a good anti‐interference ability, and effectively suppress the influence of saturation constraints on the system.

A Temporary Frequency Response Strategy Using a Voltage Source-Based Permanent Magnet Synchronous Generator and Energy Storage Systems

A Temporary Frequency Response Strategy Using a Voltage Source-Based Permanent Magnet Synchronous Generator and Energy Storage Systems

Frequency regulation strategy of direct drive permanent magnet synchronous wind power generation system based on RPC principle

Frequency regulation strategy of direct drive permanent magnet synchronous wind power generation system based on RPC principle

Direct Predictive Voltage Control for Grid-Connected Permanent Magnet Synchronous Generator System

In this paper, a direct predictive voltage control (DPVC) is proposed for the grid-connected permanent magnet synchronous generator (PMSG) system. In the proposed strategy, the dc-link voltage regulation and power regulation terms are merged into one cost function, thereby eliminating the conventional cascade control structure. The strategy selects the voltage vector that not only will generate a dc-link voltage closer to the setpoint at instant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$k+2$</tex-math></inline-formula> , but will generate an active power that can further reduce that voltage error for the future instant. To cope with the mismatch between the actual and nominal parameters, Kalman filter has been added to compensate for the steady-state error. Besides, to enhance the dynamic performance and to save the effort of parameter tuning, the weighting factor is further eliminated from the cost function by sorting the terms into two groups and independently evaluating each group in turn. To fully validate the effectiveness of the proposed strategy, the experimental test waveforms of the DPVC strategy with and without weighting factor have been presented and compared with that of the conventional PI-MPC strategy in various testing conditions.

Power electronic transformers in wind power generation systems

Power electronic transformers (PET) have received extensive attention due to their advantages of compensating reactive power, improving power quality, limiting fault current, and reducing the number of traditional transformer materials. At present, it is also an important research topic to replace conventional power frequency transformers in wind power generation systems. This paper first analyzes the topology of the primary circuit of the power electronic transformer. Several common PET topologies are introduced, and their advantages and disadvantages are analyzed. The module cascade topology and modular multilevel topology are mainly introduced, and the topological circuit diagram is given. The paper also comprehensively introduced the research status quo of wind power generation systems based on the interface of PET, permanent magnetic wind turbines and dual-feed fan wind turbines. The traditional structure of the permanent magnet synchronous generator (PMSG) system and the doubly fed induction generation (DFIG) system is shown. Finally, the problems in PET and the future development direction are summarized.

A fuzzy control and neural network based rotor speed controller for maximum power point tracking in permanent magnet synchronous wind power generation system

When the wind speed changes significantly in a permanent magnet synchronous wind power generation system, the maximum power point cannot be easily determined in a timely manner. This study proposes a maximum power reference signal search method based on fuzzy control, which is an improvement to the climbing search method. A neural network-based parameter regulator is proposed to address external wind speed fluctuations, where the parameters of a proportional-integral controller is adjusted to accurately monitor the maximum power point under different wind speed conditions. Finally, the effectiveness of this method is verified via Simulink simulation

Stability augmentation of pitch angle control for maximum power extraction of PMSG-based WTS with pitch actuator uncertainty via [formula omitted] adaptive scheme

This paper presents the stability augmentation of pitch angle control for a permanent magnet synchronous generator (PMSG)-based wind turbine system (WTS) with pitch actuator uncertainty via L1 adaptive scheme. To do this, a novel L1 adaptive scheme is firstly proposed to regulate the pitch angle at above-rated wind speed conditions and maintain the rated rotor speed in the presence of pitch actuator uncertainties in the obtained pitch system. Next, a non-affine PMSG system with uncertainties is utilized to represent the pitch regulated variable-speed WTS. Then, the L1 adaptive scheme is proposed as a stability augmentation system. At this time, the bound conditions are presented to prove the stability and performance evaluation of the proposed L1 adaptive scheme. Finally, through the simulation of the 20−MW PMSG-based WTS, the proposed algorithm proves its efficiency and applicability compared to the existing control methods.

Modified Adaptive Filter Based UPQC for Battery Supported Hydro Driven PMSG System

The standalone three phase system for power quality improvement of both the load side voltages as well as the currents of the machine terminal is presented in this paper. This standalone system consists of a three-phase permanent magnet synchronous generator (PMSG) driven by governor-less hydro turbine as a three-phase source feeding the sensitive/non-linear/linear loads, connected via a unified power quality conditioner (UPQC). The UPQC consists of a back-to-back connected voltage source converters (VSCs) sharing a common DC bus. The series compensator of the UPQC is used to eliminate voltage power quality (PQ) and to maintain the sinusoidal, balanced, and constant amplitude voltages at load terminals irrespective of any variation in the system. Moreover, the current quality such as reactive power compensation, harmonics elimination, etc. are provided by the shunt compensator of the UPQC, simultaneously while improving voltage quality issues. In addition, the efficiency of the overall system is significantly improved by running the generator below its rated voltage and reduces the losses by operating at unity pf. The system frequency and the generated voltage magnitudes are maintained during any load fluctuation or imbalance loading. The model of the UPQC based hydro turbine driven PMSG system is developed in the Simulink-MATLAB environment, and its results are presented for analysis. The validation of the system is also done on the hardware prototype, and it performs effectively for the voltage and current PQ enhancement simultaneously. It significantly improves the PQs at the generator terminals and ensures to adhere the IEC-61727 and the IEEE-519 standards even with either balanced or unbalanced loads.

Dynamic Analysis and Fuzzy Fixed-Time Optimal Synchronization Control of Unidirectionally Coupled FO Permanent Magnet Synchronous Generator System

This paper focuses on dynamic analysis and the fuzzy fixed-time optimal synchronization control problem of unidirectionally coupled fractional-order (FO) permanent magnet synchronous generator (PMSG) system. The synchronization model between FO master and slave PMSGs with capacitive and resistive couplings is built. The dynamic analysis fully reveals its abundant dynamical behaviors including chaotic oscillations and gives stability/instability boundaries with the designed numerical method. In controller design, the hierarchical type-2 fuzzy neural network (HT2FNN) with a transformation is designed to approximate unknown functions, the fixed-time command filter matched up with the compensating signal is proposed to achieve precise estimate and fast convergence, and a fixed-time preconfigured performance function integrated with a smooth and invertible function is built to realize fixed-time convergence and performance constraint. Then a fuzzy fixed-time optimal synchronization control scheme fusing with the HT2FNN, filter, performance function and optimal control is developed under the FO backstepping theory. The stability analysis proves that all signals of the closed-loop system are bounded along with the cost function being minimized. Finally, numerical simulation results verify the feasibility and advantages of our scheme.

Stability Analysis of Active Front End and Permanent Magnet Synchronous Generator With Back EMF-Based Sensorless Control for DC Marine Vessels

This article studies the influence of sensorless control on the permanent magnet synchronous generator (PMSG) and pulsewidth modulation (PWM) converter (active front end rectifier, AFE) system for dc marine vessels. Back EMF-based sensorless control is adopted in this article because the minimum speed of PMSG in a dc marine vessel is enough for obtaining a sufficient back EMF signal. First, the output impedance of “PMSG+AFE” system with a typical topology and controller is deduced by small-signal analysis. The stability analysis with constant power load (CPL) is analyzed, including the influence of sensorless control bandwidth on PMSG with a significant per-unit impedance value. Since the inductance parameter affects both the current control and sensorless control, the influence of error in the estimated inductance parameter on the stability of “PMSG+AFE” system is analyzed. To verify the proposed impedance model, output impedance is measured in the simulation and experiment. The stability analysis with the proposed impedance model and load impedance of CPL is provided in MATLAB, and simulation results and experimental measurements are given to verify the analysis.

Modeling and control of islanded DC microgrid fed by intermittent generating resources

In this paper an islanded microgrid fed through the wind and solar energy resources is presented. The power flow within the microgrid is controlled using a Neutral Point Clamped Dual Active Bridge (NPC-DAB) converter. In the proposed dc microgrid, the solar energy source is associated at the low voltage (LV) bus and the wind energy source is connected at the high voltage (HV) bus. A permanent magnet synchronous generator (PMSG) machine is used in wind energy conversion system. The real time solar radiation and wind speed data of Rupangarh, Rajasthan, India is used as an input for renewable energy resource. The NPC-DAB will work as a power electronics juncture for expediting the energy exchange in the islanded DC Microgrid. The proposed closed loop controller based on the capacitor voltage and load voltage will expedite a complete automatic operation of the islanded DC-microgrid considering various load changes. The system is studied without storage element as the automatic control of energy generation and load feeding is carried out by the NPC-DAB, also this makes the scheme cost effective. The optimum duty ratios for NPC-DAB operation are obtained and thus the increased load demand is met. The modeling of PMSG, NPC-DAB and wind energy system is discussed in details in this work. The proposed system is studied in MATLAB/Simulink environment and results are obtained for different load variations. All the wind control parameters, NPC-DAB waveforms, load waveforms are also plotted using MATLAB.

Modeling of Direct-Drive Permanent Magnet Synchronous Wind Power Generation System Considering the Power System Analysis in Multi-Timescales

The dynamics of wind power generation cannot be neglected in the modern power system and could have a great impact on the system dynamics, even raising the risk of a blackout. Because of this, power system simulation has to include the model of wind power generation. However, due to the high order of the full model of the wind power generator, it is impossible to model them in detail in the use of the power system dynamic simulation considering the thousands of wind generators in the grid. In this context, a simplified model is normally used with the trade-off in lower accuracy. As a direct-drive permanent magnet synchronous wind power generation system (D-PMSG) would take up a certain occupation in the modern power system, a proper D-PMSG simplified model is needed in the power system simulation. For a different research purpose in a different timescale, a different complexity of the model can be used to maximize the accuracy, in the meantime speeding up the simulation. This paper proposes a set of simplified models of the direct-drive permanent magnet synchronous wind power generation system (D-PMSG) and classifies them according to the timescale of the dynamics and the use cases, i.e., faults (transient stability analysis), system contingencies (voltage and frequency stability analysis) and wind speed variations (energy transformation). The accuracy of the proposed simplified models is verified by comparing them with the detailed D-PMSG electromagnetic transient mode in Matlab/Simulink, and their use case of the power system simulation is validated based on the case study of the IEEE 39-bus system considering the above scenarios.

Deployment and performance measurement of renewable energy based permanent magnet synchronous generator system

Permanent magnet synchronous generator (PMSG) is one of the promising solutions for large power generation systems due to its many advantages. The off-grid and micro/pico-hydro power stations are located near to the loads and equipped with constant speed/power turbine sources. In this paper, an attempt is made to design, develop, and deploy a three-phase PMSG generating system for the small scale off-grid dedicated load applications. In this experimental study, a constant speed source, which is an emulation of a micro/pico-hydro turbine is used as the prime mover to the generator. The prime mover is mechanically coupled to the rotor of the generator and which is controlled by an AC driver to make the PMSG run at synchronous speed for all the time of the experiment to generate the required voltage and frequency. The performance of the three-phase PMSG is measured and analyzed so that the proposed system obeys the good power quality for the pre-defined various maximum loading conditions.

Intelligent approach on sensorless control of permanent magnet synchronous generator

In this paper, a standalone permanent magnet synchronous generator (PMSG) system is designed to generate power at maximum power point (MPP). The variable speed operation of wind energy conversion system consists of PMSG, controlled rectifier and voltage source inverter co to the load. Proportional integral (PI), sliding mode (SM), and feed forward neural network (FFNN) control strategies are applied in field oriented control (FOC) at generator side converter. A comparative study on power generated at maximum power point (MPP) is done with these controllers using simulation. Hill climb search (HCS) method is applied to attain MPP. Load side inverter control strategy involves the PI and SM controllers in order to maintain the unity power factor and to control the active and reactive power for nonlinear load. The control strategies are modelled and simulated with MATLAB/Simulink. The effectiveness of proposed control method is demonstrated using simulation results.

Study of shoot-through control pulse generation for a Z-source converter with wind turbine energy system

In this paper, there is a discussion about different modulation schemes for a dc-to-ac ZSC, also named Z-source inverter (ZSI), for triggering the main switches of three-phase legs or poles of an inverter. A prototype of an 8.5-kilowatt wind turbine with a 5.8-kilowatt Permanent Magnet Synchronous Generator (PMSG) system employed with voltage-controlled ZSI is implemented in this paper. For voltage control of load side of a wind turbine generation system (WTGS), a Proportional Integral (PI) controller is used. Three types of PWM schemes namely simple boost pulse width modulation (SB-PWM), third harmonic injection boost control (THIBC-PWM) and the space vector pulse width modulation (SV-PWM) techniques are compared on the basis of total harmonic distortion of the output ac-waveform of the Z-source Converter (ZSC) to find out that, which modulation technique is the best fit for a ZSI integrated with WTGS. The pros and cons of these techniques are compared in terms of line-voltage harmonics, phase-voltage harmonics, phase-current harmonics and switching stress of switches with detailed simulation results. These different modulation techniques are implemented on the MATLAB-Simulink domain. From Total Harmonic Distortion (THD) analysis, simple boost control technique is found to be the most appropriate shoot-through control technique for a ZSI in collaboration with WTGS.

Comparative analysis of maximum power extraction and control methods between PMSG and PMVG-based wind turbine systems

The objective of this study is to compare, analyze and evaluate the performance between permanent magnet synchronous generator (PMSG) and permanent magnet vernier generator (PMVG)-based wind turbine systems (WTSs) using maximum power point tracking (MPPT) control technology. To do this, first, the dynamical model of the PMSG and PMVG-based WTS is constructed. Next, the traditional and improved optimum torque control-based MPPT schemes are employed to validate the dynamical performance between the PMSG and PMVG-based WTS. And then, the generator current augmentation-based optimum torque control strategy is proposed to extract the maximum output power from various wind conditions. This method can effectively reduce the influence of the moment of inertia in WTS and ensure the transient performance of the MPPT scheme. Further, an analytical model of 5-kW PMSG and PMVG-based WTS is presented to provide a fair comparison with MPPT schemes and outline their respective advantages and disadvantages. Finally, the comparative simulation and experimental results demonstrate the feasibility of employing PMSG and PMVG in WTS.

Power Oscillation Analysis of PMSG Wind Power Generation System Considering Power Control Nonlinearity

High proportion of renewable energy generation, especially wind power generation, has changed the dynamic behavior of power systems and leads to emerging stability issues such as oscillation accidents. The commonly used stability analysis methods based on linear system theory cannot tackle the influence of nonlinear elements in the control loop. To fill this gap, the describing function method is used to analyze the stability and power oscillations of a grid-connected permanent magnet synchronous generator (PMSG) wind power generation system in this paper. A complete PMSG system model is taken into consideration, including a wind turbine, a generator, a machine-side converter, a grid-side converter, and a weak grid. Particularly, the nonlinear element introduced by maximum power point tracking control in the power control loop is modeled and analyzed, and the influences of critical system parameters are studied. With the high accuracy of the describing function method, it is revealed that the machine-side converter mainly influences the oscillation amplitude, while the grid-side converter mainly influences the oscillation frequency. Furthermore, the following results can be obtained: 1) High bandwidth of maximum power point tracking control and rotation speed control may enlarge the oscillation amplitude, while a fast current loop of the machine-side converter is beneficial to the stability; 2) Grid-side voltage loop can significantly affect the frequency of the oscillation, and improper high bandwidth of a phase-locked loop (PLL) is harmful to system stability; 3) A stronger grid is not always beneficial to the system stability, and the influence of grid strength should be carefully analyzed and examined when nonlinear elements are considered. All analyses are verified by simulations based on MATLAB/Simulink.

Experimental investigation on performance comparison of self excited induction generator and permanent magnet synchronous generator for small scale renewable energy applications

This paper presents an experimental performance comparison of self-excited induction generator (SEIG) and permanent magnet synchronous generator (PMSG) for renewable energy-based standalone applications. These two generators have gained popularity in constant speed prime mover-driven power generation systems due to their inherent advantages. Many researchers have proposed various configurations with and without power electronics and battery energy storage for SEIG and PMSG systems. In the isolated systems, the maximum generation and load capacities are known and the primary goal is to maintain a constant voltage and frequency across load terminals. In this context, the performance comparison of both generators is needed to identify the simple, viable, and economical solution for a dedicated source and fixed isolated loads. Therefore, an attempt is made on the performance analysis of micro-hydro turbine driven SEIG and PMSG with resistor heating and induction motor driven pump load applications and compared experimentally to identify suitable voltage regulated generator. The proposed study is not employing power electronic based switches for reactive power (VAR) compensation to make the system cost effective with ease of operation. The working procedure and minimum requirements are discussed in detail for the experimental purpose. Keywords - Self-excited induction generator (SEIG), permanent magnet synchronous generator (PMSG), renewable energy sources, power generation, isolated loads, voltage regulation (VR).

Starting Control of Free Piston Stirling Linear Generator System Based on FOC

Aiming at the problem of poor system dynamic performance caused by low parameter matching in the coordinated control of Stirling engine and linear generator in the starting stage control of free piston Stirling linear generator system, a joint control method of free piston Stirling permanent magnet synchronous linear generator system based on field orientation control is proposed, based on the theoretical derivation of the mathematical model of the system and the principle of controller parameters setting, the simulation experiments of the system starting stage under several Stirling engine working conditions are carried out under simulation. The experimental results show that the stability and rapidity of the system are improved, and the dynamic response speed of generator parameters under different working conditions is accelerated, what fully verifies the correctness and effectiveness of the method. It provides an effective way to improve the control performance of the system and stabilize the power generation operation.