In this study a new technique of Direct power control (DPC) is proposed to connect distributed generation sources to the nationwide grid. This technique not only adds power of distributed generation sources to the grid, but also is capable to compensate the reactive and harmonic power of non-linear loads as well. In this study, converters’ voltage references for generating compensation current are Directly calculated in synchronous rotating coordinate system in each period of sampling; then, a proper pulse width modulation (PWM) generates the used voltages. The proposed DPC technique has some advantages including simple algorithm of fast dynamic as well as fixed switching frequency and small sampling frequency. The performance of the proposed Direct control technique is confirmed by simulation results.

This paper proposes the virtual flux based Direct power control for Vienna rectifier. No need for the input voltage sensors, the current regulation loop and PWM voltage modulation block along with the active and reactive power decoupling are some of the salient advantages of this method that make it suitable for controlling the conventional active rectifiers. However, due to the three-level nature of the Vienna configuration, balancing the output capacitors voltages is inevitable leading to a modified virtual flux based technique. Applying this modification, a separate switching table has been jammed into the proposed technique in order to control the capacitors voltages. Simulation results show the superiority of the virtual flux technique over the conventional Vienna control techniques from point of the mentioned advantages.

In this paper, a grid connected PV system acting as shunt active power filter for power quality enhancement is presented. Further, a DC-DC boost converter is used to interface the photovoltaic generator with the grid, which provides a continuous power flow from the PV generator into the grid through a Voltage Source Inverter (VSI). Hence, a nonlinear backstepping control method with predictive Direct power control for the shunt active power filter side is presented, and a suitable backstepping DC-DC boost converter is also developed, with a view to reduce harmonic currents and insuring reactive power compensation under nonlinear loads variations on the utility grid, and also extracts the maximum amount of power from the photovoltaic generator. Processor in the Loop (PIL) co-simulation results prove the performances efficiency of the implemented control algorithms under a nonlinear load operating condition.

Among a multitude of diverse control methods proposed for doubly fed induction generator (DFIG) based-wind energy conversion systems, Direct power control (DPC) method has demonstrated superior dynamic performance and robustness in presence of disturbances. However, DPC is not a flawless method and shortcomings like necessity for high sampling frequency, high-speed sensors and less noise-affected sampling circuit need to be mitigated by utilizing fuzzy controllers. Parameter setting in a fuzzy controller plays a vital role, especially under non-ideal grid conditions. In this paper, a fuzzy-genetic algorithm-based Direct power control (FGA-DPC) method is proposed for DFIG, while, the parameters of the fuzzy controller are optimized by genetic algorithm. The objective of the optimization is to minimize the stator active and reactive power errors to increase the precision of reference tracking. The objectives of the controller are also optimizing active power absorption based on the zone of operation and adjustment of reactive power according to grid requirements. The proposed method improves the overall precision and speed of transient response as well as significantly reducing power oscillations under nonideal grid conditions. Finally, to demonstrate the effectiveness of the proposed method, extensive simulations are performed in Matlab/Simulink under different conditions.

Brushless DC (BLDC) motors are used in a wide range of applications due to their high efficiency and high power density. In this paper, sensorless four-switch Direct power control (DPC) method with the sector to sector commutations ripple minimization for BLDC motor control is proposed. The main features of the proposed DPC method are: (1) fast dynamic response (2) easy implementation (3) use of power feedback for motor control that is much easy to implement (4) eliminating the torque dips during sector-to sector commutations. For controlling the motor speed, a position sensorless method is used enhancing drive reliability. For reference speed tracking, a PI control is also designed and tuned based on imperialist competition algorithm (ICA) that reduces reference tracking error. The feasibility of the proposed control method is developed and analyzed by MATLAB/SIMULINK® . Simulation results prove high performance exhibited by the proposed DPC strategy.

Among different active front end (AFE) rectifier control methods, model predictive Direct power control (MPDPC) is one of the appropriate and effective one. This method chooses best switching state based on simple calculation of converter behavior due to consideration of all possible switching states. MPDPC present good performance in balanced network condition and can control AFE rectifier with sinusoidal input currents and unity power factor. However, in the network unbalanced condition, the MPDPC shows harmonics and disturbance in the current waveform. It's almost impossible to achieve unity power factor and sinusoidal input current waveform of AFE rectifier in the unbalanced and harmonized supply condition. A new method which is the combination of the virtual flux and MPDPC with active power ripple elimination is proposed in this paper. This method uses new approach to eliminate the active power pulsation based on calculated virtual flux. Furthermore, a new current prediction method based on the virtual flux technique is proposed. This method has the advantages of VF and MPDPC techniques at the same time. control of AFE rectifier with sinusoidal input currents, unity power factor, high robustness in high percentage of unbalance, simple calculation under unbalanced and harmonized condition of the network are some advantages of the proposed method. Unlike the conventional methods, there is no need for the positive and negative sequences extraction which is a complex calculation. Simulation and experimental results are presented to confirm the effectiveness of the proposed method.

Active power filter (APF) can significantly compensate the current harmonics produced by nonlinear loads. To do this feature, harmonic detection beside harmonic generation play vital role. Direct power controller (DPC) has great harmony with instantaneous power compensation (PQ) algorithm as well as ability to eliminate internal current loops. In addition, deadbeat controller (DBC) has high compatibility for digital implementation, superior control performance and fast dynamic response. However, DBC suffers from time delay regarded to control action calculation and digital implementation. In this paper, a new deadbeat-based DPC method is proposed firstly to control and generates the harmonic currents of APF. Several simulations achieved in MATLAB/SIMULINK beside different experimental tests obtained from a DSP-based active power filter are conducted to illustrate and prove the effectiveness and superior performance of the proposed control system. As a result, the THD of grid current decreases from 22% to 3.2% under steady state where dynamic response under with/without compensation validate significant transient response lower than 5ms.

This paper presents a simple and Direct power control approach to control a single-phase grid-connected boost inverter (GCBI) for renewable energy applications. A DC voltage source and a single-phase single-stage boost inverter that is connected to the grid by an L filter form the power injection system (PIS). Unlike the conventional voltage source inverters (VSIs), the boost inverter can generate an AC output voltage with amplitude larger than the DC input one, only in a single stage. In comparison with multi-stage power c0. onversion systems, the aforementioned inverter has less number of devices and components which results in low cost and higher efficiency. Nevertheless, the boost inverter suffers from undesirable dynamic behavior and extreme fluctuation response that makes it difficult to control. Thus, the proposed power injection control system consists of two parts. First, a proper state-feedback control scheme is designed to increase damping and also improve the stability of the closed-loop system. Then, the Direct power control strategy is employed to control and track the desired powers that should be injected into the grid. Simulation results are presented to validate the effectiveness of the proposed control strategy.

Active filters are effective for eliminating harmonic currents and improving reactive power due to nonlinear loads and unbalanced sources. In this paper an effective and new method for control of active filter is investigated. Direct power control (DPC) with space vector modulation is employed for this control scheme. Also, the AC line voltage sensors with a virtual flux (VF) estimator are replaced. The control system is resistant to the majority of line voltage disturbances using by the idea of virtual flux and synchronous double reference frame phase-locked loop (SDRF-PLL) approach. Superior advantages of this method are simple algorithm, good dynamic response, constant switching frequency and resistant to the majority of line voltage disturbances. The operation of proposed control strategy is verified in SIMULINK/MATLAB simulation environment. The simulations show that this active filter is effective for eliminating reactive power injected from nonlinear loads and unbalanced sources. (NF) of low noise amplifier (LNA) are compared with each other.

This paper presents a new fuzzy Direct power control of double-fed induction generators (DFIG) in the wind power system. The most important issue in the application of DFIG generators is proper control of the active and reactive powers of these generators, which are generally carried out by vector control or Direct torque/power control methods. Direct power control (DPC) Directly controls the active and reactive powers of the stator, and stems from results from Direct torque control. To use the vector control method, it is necessary to use conventional PI controllers the main disadvantage being the controller robustness due to the nonlinear behavior of the wind turbine and blade oscillations, and it is unavoidable that after a while, the controller's coefficients need to be updated. Therefore, the main purpose of this paper is to present a Direct power control method based on fuzzy construction to overcome the mentioned problem. Simulation results of the proposed strategy are extracted under different performance conditions, and these results are compared with the conventional vector-oriented control method. These comprehensive results exhibit the effectiveness of the proposed fuzzy DPC method for the DFIGs based wind power systems.