Abdul Motin Howlader

An Integrated Power Smoothing Control for a Grid-Interactive Wind Farm Considering Wake Effects

This paper presents a power smoothing control scheme for a permanent-magnet-synchronous-generator-based wind farm considering wake effects. The integrated power smoothing method consists of a pitch angle control system, a kinetic wind-energy turbine inertia control system, and a dc-link voltage control system. Low frequency range power fluctuations caused by wind speed variations are smoothed by the pitch angle control system and the kinetic wind-energy turbine inertia control system. Power fluctuations in the high frequency range are smoothed by the dc-link voltage control system. This power smoothing approach is cost-effective because the power smoothing is made possible without additional energy storage devices. In addition, the wake effects of the wind farm are considered for power smoothing with different tower spaces. The proposed method is compared with the conventional maximum-power-point-tracking method. Simulation results confirm the proposed method efficacy in smoothing the power injected by a wind farm.

Optimal PAM Control for a Buck Boost DC-DC Converter with a Wide-Speed-Range of Operation for a PMSM

A pulse width modulation-voltage source inverter (PWM-VSI) is used for variable speed permanent magnet synchronous motor (PMSM) drives. The PWM-VSI fed PMSM has two major disadvantages. Firstly, the PWM-VSI DC-link voltage limits the magnitude of the PMSM terminal voltage. As a result, the motor speed is restricted. Secondly, in a low speed range, the PWM-VSI modulation index declines. This is caused by a high DC-link voltage and a low terminal voltage ratio. As a result, the distortion of the voltage command and the stator current are increased. This paper proposes an optimal pulse amplitude modulation (PAM) control which can adjust the inverter DC-link voltage by using a buck-boost DC-DC converter. At a low speed range, the proposed system can reduce the distortion of the voltage command, which improves the stator current waveform. Also, the allowable speed range is extended. In order to verify the proposed method, experimental results are provided to confirm the simulation results.

Output Power Leveling of a Wind Generation System Using Inertia of a Wind Turbine

Wind energy conversion systems have become important in the research of renewable energy sources. This is in no small part due to the rapid advances in the size of wind generators as well as the development of power electronics and their applicability in wind energy extraction. However, wind energy has a drawback of having only 1/800 (gm per cubic cm) density as compared to that of water energy. Wind energy does not remain constant and wind turbine output is proportional to the cube of wind speed, which causes the generated power of the wind turbine generator (WTG) to fluctuate. In this paper, a technique is proposed for output power leveling of a wind generation system. Wind turbine blades have a large inertia compared to the inertia of a generator. The inertia of the rotor behaves like an inductor in an electrical circuit. It helps smooth the wind turbine output power, stores energy during acceleration, and restores energy during deceleration. The effectiveness of output power leveling control is verified by simulations for the wind power generation system.

Parameter Identification of Wind Turbine for Maximum Power-point Tracking Control

Wind energy is a significant and powerful resource. It is safe, clean, and abundant. Variable speed power generation for a wind turbine is attractive, because maximum efficiency can be achieved at all wind velocities. However, this system requires parameters of wind turbine for calculation of the optimum wind turbine operation speed. In this paper, a technique is proposed for maximum power point tracking control of a wind generation system. The optimum operation speed to which the maximization of the output power of the wind turbine is determined takes into consideration identification of parameters by an iterative least squares technique. The effectiveness of maximum power point tracking control with the identified parameters is verified by simulations for the wind power generation system. Additionally, the paper addresses the effect on the rotational speed and output power in the event that the wind turbine parameters used in optimum rotational speed determination have error.

Fuzzy controller based output power leveling enhancement for a permanent magnet synchronous generator

Due to irregular wind velocity, the output power of a wind turbine generator system (WTGS) is fluctuated. There are many methods to propose to generate smooth output power of a wind turbine. For example, energy storage devices, electric double layer capacitors, flywheels are well-known. But these methods are required a significant extra cost for installation and maintenance. In recent years, some researches have been conducted to generate smooth output power by using inertia or by controlling kinetic energy of a wind turbine. The major benefit of this method, it does not require extra energy storage to generate smooth output power. So, it can reduce of a system cost significantly. But this method is reduced output power radically at the steady wind velocity as compare with maximum power point tracking (MPPT) control method. To overcome this problem, this paper is proposed a fuzzy controller based output power smoothing method by controlling kinetic energy of a wind turbine. The generator electrical speed is controlled by the proposed method that helps to generate efficient smooth output power at different wind speeds. The proposed method is compared with conventional method and MPPT control method. The effectiveness of the proposed method is verified by MATLAB SIMULINK with SimPowerSystems and Fuzzy Logic Toolbox.

Output power leveling of wind generation system using inertia for PM synchronous generator

Wind energy conversion systems have become important in the research of renewable energy sources. This is not a small part due to the rapid advances in the size of wind generators as well as the development of power electronics and their applicability in wind energy extraction. However, wind energy has a drawback of having only 1/800 density as compared to that of water energy, and it does not remain constant and wind turbine output is proportional to the cube of wind speed, which causes the generated power of wind turbine generator (WTG) to fluctuate. In this paper, a technique is proposed for output power leveling of a wind generation system. Wind turbine blades have large inertia compared to the inertia of generator. The inertia of the rotor behaves like an inductor in an electrical circuit. It helps smooth the wind turbine output power, stores energy during acceleration, and restores energy during deceleration. The effectiveness of output power leveling control is verified by simulations for the wind power generation system.

Output power control of a PMSG based wind turbine in strong wind conditions

This paper presents a method for controlling the output power of a permanent magnet synchronous generator (PMSG) in strong wind conditions. Currently, most of wind turbines are stopped and disconnected from the power system when wind speeds reaches more then 25 m/s. This will lead to detrimental power and voltage fluctuations in the power system. To overcome this problem, output power, pitch angle and rotation speed command values are designated. A novel method, which includes pitch angle and rotation speed control is proposed. Simulation results show that the wind turbine can generate stable power during strong wind conditions.

Optimal scheduling method of controllable loads in smart house considering forecast error

From the perspective of global warming suppression and depletion of energy resources, renewable energies, such as the solar collector (SC) and photovoltaic generation (PV), are getting attention in distribution systems. Houses with PV and heat pump (HP) systems are also gaining wide use recently in residential areas recently because of using time-of-use electricity pricing. Thus, optimal scheduling of the distributed energy resources (DER) is required to reduces the operational cost for the consumers, however DERs of then deviate from forecast data. Hence, optimal scheduling of these appliances may not be achieved due to uncertainty of the weather. In this paper, we propose an optimal scheduling method of controllable loads considering forecast error in the smart house, where HP, fixed battery and EV systems are used as controllable loads. The scenario based approach is applied in roder to solve the optimization problem involving the uncertainty. Furthermore, a novel electricity pricing system is also suggested in this paper. In order to confirm the proposed method is useful, and in to verify the effectiveness of the proposed system, MATLAB® is used for simulations.

Wide-speed Range Operation of Interior Permanent Magnet Synchronous Motor with Parameter Identification

Abstract To realize the maximum efficiency control and/or flux-weakening control for interior permanent magnet synchronous motors, exact motor parameters are typically required. It is well known that motor parameters vary with driving conditions such as temperature and magnetic saturation. In this article, the effect of parameter variations on the performance of maximum efficiency control and flux-weakening control are quantitatively investigated. Then, an on-line parameter identification method is proposed to prevent parameter variation from degrading the control performance. This method simultaneously identifies motor parameters involved in the control strategies by using both the recursive least-squares method and constant gain adaptive identification method. The effectiveness of the maximum efficiency control and flux-weakening control incorporated with on-line parameter identification strategy is confirmed by computer simulations.

A new robust controller approach for a wind energy conversion system under high turbulence wind velocity

Wind energy is a uncertain fluctuating resource, requires tight control management. So, the classical proportional integral (PI) control is not perfect during high turbulence wind velocities. This is raising interest towards the robust control strategies. Due to implementation complexity for a continuous H∞ controller, and availability of the high speedy microcontrollers, the design of a sample-date or digital H∞ controller is very important for practical implementation. This paper is proposed a digital H∞ controller scheme comprises for both generator and grid interactive power converters, and the control performance is compared with the conventional PI controller. Effectiveness of the proposed method is verified by the numerical simulations.