جستجوی مقالات مرتبط با کلیدواژه « direct power control » در نشریات گروه « برق »

Brushless dc motors (BLDC) are widely used in industrial applications due to their simple structure, high efficiency and long lifetime. The drive of these motors also has a fast transient response and has high quality waveforms in steady state. In this paper, the direct power control using the model predictive method with finite control set (DP-FCS-MPC) is presented in BLDC motor drive and compared with the conventional current control method based on FCS-MPC. This comparison is made under the same operating conditions and includes the steady state operation of the BLDC motor. The simulations performed in PLECS software show the performance of both methods in BLDC motor speed control under sudden load changes. Nevertheless, it is shown that the direct power control using model predictive method with finite control set has better performance in terms of torque ripple reduction, less speed and torque fluctuations, less active and reactive power ripple, and current waveforms with less harmonic distortions.

In this paper, a finite-control-set model predictive control method is presented for closed loop control of an active front-end rectifier. The method used has a discrete-time function and does not require any additional modulators. The interesting point in the control algorithm is how to control the dynamic references. The control strategy is able to provide proper references for source active power and DC voltage, without the need for additional control loops. In order to better understand the performance, the proposed control method is compared with the model predictive direct power control (MPDPC) method. The results obtained using Matlab/Simulink software show that the proposed method, while having all the capabilities of the MPDPC method, including proper tracking of active power and DC voltage and low current THD, by removing the PI controller and its related disadvantages, it has better stability and faster transient response.

One of the most used methods for exploiting wind energy is the use of wind turbines, these turbines are used to generate electricity. They use different electric machines, and among these machines, the two-way induction generator has a greater share due to its advantages.In this article, a direct power control method based on fuzzy controller for wind turbines equipped with DFIG generators is presented.In this method, the required voltages of the converter on the rotor side are calculated directly based on the phase controller, stator voltage, rotor speed and some machine parameters.
On the other hand, PWM modulator has replaced hysteresis comparators. In this presented method, the switching frequency is fixed. The simulations for the presented method have been done in steady and transient conditions

This paper proposes an integral sliding mode direct power control (ISM-DPC) strategy for brushless doubly fed induction generators. Two widely applied control strategies are available for this type of generators: hysteresis-based direct power control and vector control. Direct power control suffers from high power ripples and current distortions produced by variable switching frequency. Moreover, the tuning issues of PI controller, which are highly reliant on machine parameters and operating conditions, and necessity of a phase-locked-loop for frame alignment are accounted as limitation of these methods. The proposed integral sliding mode strategy directly controls active and reactive power to provide fast dynamic response and zero steady-state error. This method is developed in the control winding reference frame to avoid the application of PLL. A large-scale brushless doubly fed induction generator (BDFIG) is simulated to validate the effectiveness and robustness of the proposed ISM-DPC method in comparison with widely applied methods, vector control and direct power control.

In this paper, direct power control (DPC) was used for active and reactive power control of DFIG in constant speed reference and variable turbine speed reference based on the optimal power curve. On the other hand, wide application of nonlinear loads in power networks has caused problems such as high current harmonics. Non-linear loads act like harmonic current sources and inject harmonic currents into the supply network. The presence of harmonics in the network causes the harmonic voltage drop and causes other consumers to receive distorted supply voltage, which may cause overheating of power factor correction capacitors, motors, transformers and cables, and mal-operation of some protection devices. Since DFIG is responsible for injection of active and reactive power to the network, it is possible to compensate for the fluctuation of power due to nonlinear loads in the network by proper power injection. Therefore, in this paper, direct power control is implemented to control the power of DFIG, and also to reduce the network current harmonics in the presence of nonlinear loads by using the proper control methods through the rotor side converter and grid side convertors. In this regard, the Matlab/Simulink software is used to simulate a system including a DFIG-based wind power unit and the results are analyzed and compared in different scenarios. The results indicate that accurate and fast control of the DFIG power is along with a significant reduction of network current harmonics.