Siding Mode Control for PMSG based Wind Energy Conversion System connected to the grid

Wind energy is one of the most available and exploitable forms of renewable energy. Variable speed PMSG based Wind Energy Conversion System (WECS) offers many advantages compared to the fixed speed squirrel cage induction generators such as improved stator output operation at better power factor, no maintenance cost for gear box (as it is direct-driven) reduction in weight and losses, higher efficiency and ability to run at low speeds. The elimination of the gear box and brushes can enhance the efficiency of wind turbine by 10%. In this paper a Permanent Magnet Synchronous Generator (PMSG) is modeled whose stator is connected to the constant single phase load (in place of grid) through AC/DC thyristors based rectifier followed by capacitor (dc-link) and DC/DC converter control. Overall arrangement provides constant output to connected load if applied with proper controlling techniques. Hence this proposed wind generation system design can be extended for grid connection also via DC/AC inverter control. Results are simulated and verified in MATLAB/Simulink platform at constant rated (12m/s) and varying (stepped) wind speed for smooth and constant output voltage. DOI: http://dx.doi.org/10.11591/telkomnika.v13i3.7097

This study recommends a robust modified perturb and observe (MPO) for tracking the maximum power point (MPP) based on the variable speed - wind energy conversion system (VS-WECS) to reduce downsides of traditional P& O algorithms. The MPO separates the power-speed (P-o)) curve into several operating regions (each region has a definite step-size) by associating a suggested ratio, that hangs on estimating of the reference power, with a predefined value. For the regions nearby the peak, a small step-size is used. Else, a large one is employed which enhances the tracking speed. To minimize fluctuations around the MPP, small different step-sizes are applied in the reverse direction compared to the forward direction. The VS-WECS scheme contains a multi-phase permanent magnet synchronous generator (PMSG) with the support of the frequency converter and the dc-link capacitor for the grid amalgamation. Simulation results show that the MPO raises the WECS efficiency by 4.0% with reduction on oscillation levels. The dynamic performances of the VS-WECS is established using MATLAB/SIMULINK.

This paper aims to develop a coordinated controller to enhance the low voltage ride through (LVRT) performance of a permanent magnet synchronous generator (PMSG) based variable speed wind energy conversion system (WECS). This coordinated control comprises of a pitch angle control, a flux weakening control and a static synchronous compensator (STATCOM) control. The pitch angle control is adjusted to smooth the WECS output power fluctuations or to enhance the LVRT performance. The flux weakening controller is used to reduce the overvoltage of DC-link capacitor, and the STATCOM control is used to ensure continuous operation of WECS during symmetrical and asymmetrical grid faults. The proposed coordinated control method is compared with the conventional LVRT strategy based on the braking chopper (BC) via time series simulation results and effectiveness of the proposed control is verified.

Conventional wind energy conversion systems (WECS) typically employ rotor side synchronous frame current control strategies to regulate the active/reactive power supplied by the WECS generator. Such strategies require accurate information regarding the rotor position and speed in order to set the dq frame reference currents and to perform the necessary frame transformations. This information can be obtained using a rotor speed sensor (i.e. a shaft encoder) or via a sensor-less strategy in which a dynamic machine model and stator current measurements are used to estimate the true rotor position. This paper now presents an alternative approach to control the active/reactive power supplied by the WECS permanent magnet synchronous generator (PMSG). The proposed strategy uses the three phase converter modulation commands to identify the phase and frequency of the PMSG stator terminal voltages. This enables the direct regulation of the real and reactive power extracted at the PMSG terminal voltages using a stationary frame Proportional + Resonant (PR) stator current regulation strategy, without requiring precise knowledge of the rotor position. Maximum power point tracking (MPPT) functions are realized using the measured PMSG terminal voltage frequency to form an estimate of the rotor speed. The result is a simple robust WECS control strategy that rapidly and accurately tracks rotor speed changes caused by wind speed variations. Detailed simulation and experimental results obtained for a scaled laboratory prototype system are presented to validate the proposed strategy.

The limitations of fossil fuel-based energy sources, such as rising prices, environmental harm, scarcity, and pollution, underscore the urgency of transitioning to renewable energy. Harnessing wind energy efficiently requires implementing various control strategies due to its unpredictable nature. This paper introduces a 3L multilevel converter integrated with a Permanent Magnet Synchronous Generator (PMSG)-based wind energy conversion system (WECS). It delves into the design considerations of WECS components, encompassing the fundamental models of two drivetrains and wind turbines. The adaptive fuzzy logic control, coupled with a PI type maximum power point tracking (MPPT) algorithm, optimizes wind energy extraction. Additionally, the utilization of 3-L multilevel converters enhances the system's efficiency. The primary objective is to maximize energy extraction from the wind, ensuring the system's high efficiency. To achieve maximum power point tracking across diverse conditions, the developed control algorithm undergoes rigorous testing using simulation software. By integrating diode rectifiers, 3-L boost converters, and 3-L multilevel inverters, the system maintains balanced and regulated output voltage, current, and power amidst varying input/output conditions and disturbances. Compared to conventional methods, the Intelligent Control Strategy proves superior, exhibiting enhanced stability, precision, and performance with robust dynamic response under fluctuating wind speeds.

The following topics are dealt with: renewable energy sources; energy conservation; computer aided engineering; thermal power stations; solar power stations; solar absorber-convertors; distributed power generation; photovoltaic power systems; domestic appliances; humidity.

Wind Turbines with Permanent Magnet Synchronous Generator and Full-Power Converters: Modelling, Control and Simulation

Wind energy conversion systems analysis of PMSG on offshore wind turbine using improved SMC and Extended State Observer

Wind energy has established as fastest growing renewable energy technology. During last few decades world has witnessed multidimensional development in this area and made this technology acceptable for efficient production of bulk power. Recent research articles and renewable energy market trends have demonstrated the popularity of permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) for such requirements. Objective of present work is to examine the performance of the cylindrical pole PMSG based wind turbine (WT) interfaced to the grid via back-to-back voltage source converter. Present work focuses on generator performance with zero d-axis current control (ZDC) and maximum torque per ampere control (MTPA), it has been observed that cylindrical rotor PMSG displays identical performance with ZDC and MTPA control. In order to analyze the WECS performance, simulation is done in MATLAB/Simulink platform. Excellent performance is observed and is validated with the obtained performance parameters for the system at steady state. The WECS performance is studied in maximum power point tracking (MPPT) range only.

Recently, as wind energy has increased considerably in the electric power generation system, the wind turbines must maintain connected to the grid and improve the system stability during and after the grid faults. The enhancement of fault-ride through (FRT) capability of permanent magnet synchronous generator (PMSG) based on wind energy conversion system (WECS) is a vital issue. An active crowbar protection system in this paper is proposed to the improvement of FRT capability and the enhancement of the power quality of PMSG based on WECS system during and after the grid faults. The active crowbar in this paper is designed from a series resistor with an insulated gate bipolar transistor (IGBT) switch, unlike the passive crowbar, which has only one resistor. The active crowbar protects the power converters from the damaging effects of overcurrent during grid fault. The main aims of the active crowbar system are reduction of the amplitude of stator fault voltages, remains constant DC link voltage, general enhancement in all response of the PMSG, minimizing in the trigger time of the active crowbar. These aims are achieved with the introduction of the active crowbar between the machine side converter (MSC) and PMSG. The proposed protection system implemented a 1.5MVA PMSG based on WECS during different grid faults conditions using MATLAB/Simulation. The proposed protection system is compared with without protection system during different faults conditions and the validity of the proposed protection system is verified by simulation results.DOI: http://dx.doi.org/10.5755/j01.eie.24.2.20637

To address the stochasticity issues of wind power generation, this article proposes an anti-disturbance full-order sliding-mode control (FOSMC) strategy for the current control of permanent-magnet synchronous generator (PMSG)-based wind energy conversion systems (WECSs). An extended state observer (ESO) is designed to estimate the uncertainty of the external disturbances and internal model parameters in real time. An FOSMC strategy is designed for the current control of the PSMG. The FOSMC uses a continuously controlled sliding mode to solve the chattering problem and the disturbances estimated by the ESO to improve the antidisturbance capability while ensuring finite-time convergence of the system states. Experimental results for a 900 W emulated PMSG-based WECS are provided to validate the superior current tracking, chattering suppression, and antidisturbance performance of the proposed ESO-FOSMC strategy over a sliding-mode current controller using the same ESO for antidisturbance.

To enhance the control and stability of the wind energy conversion system (WECS) based on direct drive permanent magnet synchronous generator (PMSG), this artefact presents a modified sliding mode control approach. A detailed time domain dynamic model of PMSG-based WECS integrated to infinite bus is also presented in terms of d-q reference frame. In order to compensate the general limitations with regard to various control strategies, a proportional integral (PI) type sliding surface-based fast sliding mode control is executed for the above. A current control strategy has been suggested for real and reactive power control keeping voltage under the desired limit. To justify the superior performance of the proposed controller in terms of robustness, reliability and accuracy compared to PI controller, the control strategy is validated through MATLAB simulation, when the system is subjected to diverse operating conditions like wind speed and system parameter variations.

Today wind energy has emerged as an alternative energy source for power generation. This paper investigates about standalone Permanent Magnet Synchronous Generator (PMSG) based wind energy conversion system (WECS) with Maximum Power Point Tracking (MPPT). The proposed system comprises of Wind turbine (WT), PMSG, boost converter, uncontrolled diode rectifier, battery bank, bidirectional buck boost converter and dc load. Multi pole PMSG is best suited for low speed, wide range variable speed wind energy applications. Wind flow varies with time; as a result power produced also varies. As maximum power has to be tracked for varying wind speeds, perturbation & Observation (P&O) algorithm is implemented for MPPT. Battery storage system is essential to supply the load during low wind speed condition. In this paper, a simulation study of the proposed standalone system is done using SIMULINK in MATLAB.

Wind energy production systems (WEPS) are increasingly vital in the transition to renewable energy sources, with permanent magnetic synchronous generators (PMSG) being widely adopted due to their high efficiency and reliability. Developing robust control methods is essential to ensure that WEPS operate efficiently even under adverse conditions. This study focuses on optimizing control strategies for WEPS utilizing a 5‐phase PMSG and addresses challenges posed by double‐phase open fault (DPOF) scenarios. Unlike conventional second‐order sliding mode control (SOSMC) based on the super‐twisting algorithm (STA), the proposed method enhances performance by elevating the sliding surface time derivative degree to a third order and modifying the discontinuous term of STA with an arctangent function, promising to reduce chattering effects. Additionally, an adaptation law adjusts the improved STA gains, forming adaptive‐gain third‐order sliding mode control (AG‐TOSMC), which outperforms SOSMC under various disturbances such as wind speed fluctuations, parameter changes, and DPOF scenarios. The AG‐TOSMC enhances the quality of active and reactive power by reducing fluctuation ratios compared with the SOSMC. The efficiency of WEPS increases to 98.5% with AG‐TOSMC, surpassing the 93.5% achieved with SOSMC. Additionally, a DPOF test confirms the aptitude of the 5‐phase PMSG to work under degraded circumstances, supplying appropriate electrical power to the network without significant adverse effects. Numerical simulations validate the efficiency of the suggested WEPS and its control, demonstrating superior performance achieved with AG‐TOSMC.

Augmenting effectiveness of control loops of a PMSG (permanent magnet synchronous generator) based wind energy conversion system by a virtually adaptive PI (proportional integral) controller