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.
The high penetration level of power electronics interfaced Distributed Generation (DG) systems creates great ancillary services potential through the DG interfacing converters (IFCs) such as the grid unbalanced voltage compensation. However, the unbalanced voltage compensation may cause adverse effects on the IFCs' operation such as output active power oscillation and DC link voltage variations. Moreover,...
CSC topology with natural advantages in terms of simple structure, grid friendly waveforms, controllable power factor, and reliable grid short-circuit protection is considered to be a promising converter configuration for use in mediumvoltage (kV) high-power (MW) PMSG based wind energy systems. In view of this, three types of configurations for current source converter (CSC) based medium-voltage PMSG...
This paper presents a grid-connected seven-level cascaded H-bridge converter operating as photovoltaic inverter. The main issue with this topology are the natural power imbalances between the power cells and the phases of the converter. The control problem is addressed with a Multiobjective Finite Control Set Model Predictive Control, where a dc-link voltage balance among the cells and good tracking...
High voltage direct current (HVDC) transmission systems have proven to be a cost effective solution for very-long distance transmission requirement. Among the different HVDC technologies, the modular multilevel converter (MMC) based HVDC systems have become quite popular. It has the special features like transformer-less operation, completely modular design and a common DC-bus. Due to the above features,...
This investigation presents a grid-connected five-level H-bridge neutral-point-clamped converter operating with a single dc-link as photovoltaic power source. The operation with a single dc-bus is enabled by adding a transformer with open-end winding secondary, where each power cell of the converter is connected. The proposed control scheme is validated trough simulation results and tested under dynamic...
With the high level penetration of power electronics interfaced Distributed Generation (DG) systems, applying these systems to compensate the grid voltage unbalance is becoming an important and interesting ancillary service for the utility. However, compensating the unbalance voltage leads to active power oscillation from the DG and may cause adverse effects of the DG operation. This paper proposes...
This paper proposes a novel architecture for Plugin Electric Vehicles (PEVs) dc charging stations, through the use of a single dc-link 3-level h-bridge (HB) converter as the grid interface. This feature is achieved by the use of an open-ended secondary windings transformer at the grid side. The proposed solution enables fast charging for PEVs concentrating several charging units into a single grid-tied...
Common-mode voltages (CMVs) can lead to premature failure of the motor insulation system in medium-voltage (MV) current source drives. This paper proposes a novel space-vector modulation (SVM) based gating strategy that can significantly reduce the peak CMV by optimizing the switching sequences for MV current source converters (CSCs). In the proposed method, the switching sequence of one side of the...
This paper proposes a novel control technique to improve the power factor over a wide range of wind speed in a wind energy conversion system (WECS) based on a current source inverter (CSI) and an electrically excited synchronous generator (EESG). The system consists of diode rectifier on the generator-side while a pulse wave modulated (PWM) CSI is on the grid-side. In the proposed control scheme,...
The voltage-boost characteristic of the pulse-width-modulated (PWM) current-source inverter (CSI) is in accordance with the nature of a variable-speed wind energy conversion system (WECS). In view of this, low-cost power converter solutions using diode/thyristor rectifier with PWM CSI are proposed and investigated in this paper for wind power generation applications. Detailed steady-state analysis...
A new interconnecting approach for an offshore wind farm is used, where same number of cascaded pulse width modulated (PWM) current source converters (CSCs) are used on both generator and grid side. This paper presents a novel control scheme which enables maximum power acquisition from the wind for every wind turbines in the wind farm and aggregate power is equally shared by the grid side CSCs with...
In this paper, an input power factor compensation method is proposed for a high-power pulse-width-modulated Current-Source-Converter (CSC)-fed Permanent Magnet Synchronous Motor (PMSM) drive system. The proposed method is based on controlling the d-axis stator current component in the field oriented control scheme of the drive system. The CSC-fed PMSM drive system and its field oriented control scheme...
A novel converter configuration is proposed in this paper for mega-watt wind energy conversion system (WECS) using permanent magnet synchronous generator (PMSG). The converter consists of a diode rectifier, a buck converter and a pulse-width-modulated (PWM) current source inverter (CSI). Two DC current requirements in the system are analyzed and compared: one from the generator and diode rectifier...
This paper presents a novel interconnecting approach for an offshore wind farm, where pulse width modulated (PWM) current-source converter(CSC) of each wind generator is series connected and dc output is fed by submarine cable to the series connected PWM CSCs on grid side. The total number of series connected PWM CSCs for the onshore grid connections are equal to the number of wind generators installed...
A fast simulation platform dedicated to Micro Grid (MG) applications is proposed in the paper. The proposed simulation platform is essentially an additional library of the general simulation software PSCAD, which includes components and models in MG application. The content of the proposed simulation platform is introduced with 2 example models. A seamless control strategy is proposed to evaluate...
As more distributed generators join the utility grid, the concern of unintentional islanding increases. This concern is due to the safety hazards this phenomena imposes on the personnel and equipment. Passive anti-islanding methods monitor grid parameters to detect islanding, whereas active methods inject perturbation into current waveform to drive theses parameters out of limit. The performance of...
The increasing influence of wind power in the power system operation has caused the power system operators to include wind power plants in the control of the overall power system, both in steady-state and transient operation. Therefore, the grid connection requirements of the power system operators involve wind power systems. Low voltage ride-through requirement is probably the most demanding grid...
The active islanding detection methods (IDMs) can effectively mitigate the islanding non-detection zones (NDZs) compared with passive IDMs in the inverter based DG systems but the improvement depends highly on the interface control schemes. In this paper, different reactive power variation based IDMs, including Active Frequency Drift method (AFD), Slip Mode Frequency Shift Method (SMS) and Sandia...
This paper presents a generalized direct power control (DPC) scheme for grid connected multilevel converters. The proposed method extends the original DPC operating principle by considering only for selection the closest vectors to the present switching state. This approach requires the power derivatives for feedback, which can present numerical implementation problems in real time. Therefore a grid...
This paper proposes a power factor control strategy for a current source drive with active front end, where the selective harmonic elimination (SHE) modulation is employed for the rectifier and a combination of space vector modulation (SVM) and SHE is used for the inverter to guarantee best waveforms at a low switching frequencies. The proposed power factor compensation strategy comprises two methods:...
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.