The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A simplified current reference control for single-phase shunt active power filter (APF) to compensate the current harmonics and reactive power required by nonlinear loads is being presented in this paper. The key intention of this method is to represent the APF in parallel with nonlinear load as an equivalent conductance. In the proposed technique, first the distorted voltage signal of PCC is made...
New regulatory requirements outlined in the European Grid Code dictate fault ride-through and reactive power support requirements for wind energy conversion systems. This paper introduces a simple emergency control scheme for DFIG-based wind turbines to comply with the grid code requirements. The proposed control design uses an enhanced phase locked loop (PLL) system to extract the synchronization...
Different kinds of sources with different capacities can be connected to a Microgrid. In autonomous operation when Microgrid is disconnected from the main grid, beside feeding total load and sharing power between sources, voltage and frequency requirement of the loads should be met. In this paper a droop control is applied to a standalone multi-converter based power system. Frequency and voltage are...
This paper focuses on an active shunt compensator suitable for reactive, unbalanced and harmonic loads under both balanced and unbalanced operating conditions of the grid. A stationary reference frame based controller with multiple resonant peaks (proportional + multiresonant controller) is used in order to achieve high accuracy of current compensation. However, the performance of the system depends...
The article focuses on control strategies of single-phase two-stage grid connected photovoltaic (PV) generation systems. The principle and digital implementation of instantaneous current control, based upon the parameters of the inverter, is presented. This method can be used to achieve accurate tracking results and lower Total Harmonic Distortion (THD) of current. A novel Phase Locked Loop (PLL)...
The increasing penetration of generation power plants based on renewable energies in the electrical networks has boosted the number of systems connected to the grid. In this scenario the microgrid, providing advanced functionalities to improve the stability and operation of the network, have become very popular. In this paper a control strategy for the microgrid management is presented. The proposed...
In this paper is presented the structure and working principle of the cascaded H-bridge multilevel converter with PWM rectifier and phase-shift transformer. Using the leak inductance as the filter reactor of the PWM rectifier can reducing the volume and cost of the converter; the phase-shift secondary side of the transformer can eliminate the current harmonics caused by the single power unit, restraining...
This paper presents a single phase grid-connected PV system integrating energy storage system (ESS) using cascaded multilevel inverter. A Discrete Fourier Transform (DFT) Phase Locked Loop (PLL) method is proposed to improve system dynamic performance. A coordinated active and reactive power management (ARPM) strategy is developed based on the dual-stage DFT PLL method. The point of common coupling...
This paper presents a control scheme for microgrids with passive loads. The existing control techniques for distributed generation systems are designed to operate either in the grid-connected or in the islanded mode. In the grid-connected mode of operation, a current-controlled scheme based on d-q variables is used for the regulation of real and reactive powers of the converter. In the islanded mode...
Phase locked loop (PLL) is an important part of the current-controlled grid-connected converter. Its job is to estimate the phase angle of the grid voltage. If the PLL is not robust, the grid-voltage distortion will lead to an error in the estimated phase leading to a degradable performance of the converter. In this paper, the effect of the PLL on the operation of a current-controlled voltage-source...
The increasing penetration of generation power plants based on renewable energies in the electrical networks has boosted the number of systems connected to the grid. In this scenario the microgrid, providing advanced functionalities to improve the stability and operation of the network, have become very popular. In this paper a control strategy for the microgrid management is presented. The proposed...
This paper investigates the operation of a current controlled Voltage Source Converter (VSC) under weak grid conditions caused by large grid impedance. Three different current controller structures are investigated; the conventional decoupled PI-controller in the synchronously rotating reference frame, Proportional Resonant (PR) controllers in the stationary reference frame, and the phase current...
Current control is crucial in active power filters. The current controller should provide perfect tracking of reference and total rejection of disturbance (grid voltage). The use of resonant controllers has been often proposed as one of the highest performance alternatives for alternating current and voltage control. In this work it is studied the effect of the discrete-time implementation of resonant...
There are many consumers and equipments in distributed generation (DG) systems and distributed networks which have rapid changes in the reactive power consumption. These changes can result in large variations in the load-side voltage that may affect the operation of other power consumers which are fed from Point of Common Coupling (PCC). In this paper a current control strategy for inverters, based...
Bit-stream is a new technique for controlling power electronics applications by interconnecting appropriate control elements inside an FPGA. This paper presents a Bit-Stream based controller for a three phase, 400 V / 7 kVA reversible rectifier, which is used to transfer power between an AC line and a DC bus in a controlled manner. The proposed controller is based on vector control techniques, which...
This paper compares different control schemes for single-phase PWM inverter to achieve zero steady-state error under large varying load conditions. PR control and load current feedback control improve the steady-state and transient performance respectively. However, the load current feedback control is subject to control stability issue under some load conditions. The PR and synchronous d-q frame...
This paper proposes a mathematical model and a voltage/frequency regulation strategy for an islanded, electronically-coupled, distributed resource (DR) unit. The DR unit can either represent a distributed storage (DS) unit or a dispatchable distributed generation (DG) unit. The proposed control strategy benefits from the power circuit configuration, dq-frame current-control scheme, and the phase-locked...
Islanding of a voltage source converter (VSC) equipped DG unit is considered in this paper. Some internal controller signals are implemented in the islanding detection method in order to provide a robust operation. Particularly, the estimated frequency of the grid voltage along with a point of common coupling (PCC) voltage regulator and a dynamic reference-current limiter are proposed for islanding...
In this paper an implementation of improved voltage oriented control for AC-DC converter has been presented and investigated. Algorithm is based on independent control of positive and negative current sequences. It contains different blocks responsible for grid synchronization, mitigation of 100 Hz component, current control and sequence extraction. Different line voltage feedforwards have been implemented...
For parallel operation of electric network it need to control the current to be in phase with the electric network voltage. This paper presents a control method of phase tracking based on artificial neural network. After comparing the simulation results between BP network and RBF network, it takes the algorithm of RBF network into phase locked loop. It takes the electric network voltage as the expected...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.