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.
Hot reserved redundant sub-modules significantly increase the reliability of MMC systems equipped with considerable sub-modules. This paper presents a fault-tolerant operation scheme for an MMC with a distributed control architecture. The MMC output, internal dynamics and the average capacitor voltages are balanced and well-regulated while asymmetrical sub-modules in arms are bypassed due to faults...
Fault tolerant operation can significantly improve the reliability of a Modular Multilevel Converter (MMC), but the precondition is that a fast and accurate fault detection and localization method has been embedded into the MMC control system. This paper proposes a fault diagnosis method used in a distributed control architecture, which makes the local controllers capable of identifying the switching...
To ensure the reliability of insulation systems of Type-II inverter-fed motors driven by power electronics, endurance tests should be performed at sinusoidal or repetitive impulsive voltage higher than the partial discharge inception voltage (PDIV) on insulation systems/models according to the standards released by the International Electrotechnical Commission (IEC). When repetitive impulsive voltages...
Power electronic converter loads are widespread in DC distributed power system. These tightly controlled converter loads behave as constant power loads (CPL) and may cause stability issue when fed by a source converter. This paper proposes a nonlinear control method to stabilize DC/DC boost converter feeding CPL. The proposed controller is based on adaptive backstepping and nonlinear disturbance observer...
In order to stabilize the power fluctuation caused by distributed energy in the bipolar-type DC micro-grid, a new hybrid energy storage system (HESS) coordination control strategy is proposed in this paper. First, in order to take advantage of lithium battery and super capacitor complementary performances, a cascade structure of the lithium battery and the super capacitor is adopted. Meanwhile, voltage...
In this paper, an adaptive integrated hybrid AC/DC microgrid module is proposed to accommodate a wide range of Distributed Renewable Energy Resources (DRERs), Distributed Energy Storage Devices (DESDs) and Distributed Demand Resources (DDRs) into the existing distribution systems. The concept and the architecture of adaptive integrated hybrid AC/DC microgrid module have been elaborately explained...
This paper explores the interconnection of multiple microgrid with “tie-line”. Tie-line control can be managed to control the power flow from microgrid and voltage at respective microgrid buses at the point of interconnection. Formation of such DC microgrid cluster ensures higher reliability of power supply and flexibility to manage distributed energy resources and loads in the system. Two identical...
The multi-actuation-based model predictive control (MPC) method can significantly improve the steady-state performance of cascaded H-bridge (CHB) inverters. However, a large computational burden is generated on digital controller when this method is applied for CHB inverter due to its large number of control actuations. In this paper, a new MPC method is proposed for a single-phase CHB inverter. In...
A bipolar dc microgrid features three voltage levels and is capable of transmitting power more efficiently than a unipolar system. This paper proposes a droop control to achieve load sharing and voltage balancing in such a microgrid system. Droop control is adopted to ensure that autonomous sharing of load power can be realized without communication. Moreover, the positive and negative pole voltages...
Hybrid energy storage system (HESS) facilitates the integration of various energy storages (ESs) with different ramp rate. Virtual capacitive control (VCC) is used to ensure the idle condition of supercapacitors (SCs) when HESS is in steady state and dynamic power sharing in transion. Improved virtual capacitive droop (IVCD) is proposed in this paper by introducing DC bus voltage regulation for batteries...
Repetitive wave voltages should be used to perform partial discharge inception voltage (PDIV) tests on insulation systems of type I rotating machines fed by power electronics in qualification and type tests according to new standards published by International Electrotechnical Commission (IEC). To obtain objective test results, the influence of waveform parameters on PDIV results should be carefully...
Microgrid is widely implemented for system with high penetration of renewable energy sources. Multiple microgrids can be interlinked to form a Power Park which can be used for wider area applications. Centralized power park control, in which one of the microgrid operate as the voltage/frequency regulator while the power exchange of the rest microgrids with power park network, is determined by the...
This paper presents a review of secondary control strategies for DC microgrids (DC MGs) and compares centralized, decentralized and distributed control approaches. The conventional droop control provides proper power sharing among converters with the increment in droop gain. However, this droop gain is inversely proportional to the output current consequently leading to current sharing inaccuracy...
Multiple-voltage-region control, in which the bus voltage range is divided into several regions, is usually implemented for DC microgrid operation in distributed manner. Voltage/power droop relationships are imposed for active power sharing among slack terminals. Conventionally, threshold voltages for voltage region partition are determined with fixed percentage of variation around the nominal value,...
In a DC microgrid (MG) with droop control system only, there exists an inherent deviation between DC bus voltage and its rated value during the steady-state operations. In order to eliminate the inherent deviation, a secondary voltage regulation system (SVRS) based on vanadium redox battery (VRB) storages is proposed in this paper. It adopts double closed loop control strategy coordinating with the...
In this paper, a new coordination photovoltaic/battery micro-grid control strategy is proposed to improve the micro-grid fault ride-through capability. Under normal condition, the proposed strategy can restrain the influence of load fluctuations. When symmetrical grid fault happens, the micro-grid can ride through it by the proposed strategy. The DC-link bus voltage and AC current could be kept stable...
To ensure insulation system reliability of rotating machines driven by power electronics, accelerated tests under repetitive impulsive voltages should be performed on turn-to-turn insulation according to technical specifications provided by the International Electrotechnical Commission. Due to the fact that the voltage parameters of repetitive impulsive voltage can influence the insulation lifetime...
The differential current in Modular Multilevel Converters (MMCs) is inherently subjected to even order harmonics, which are mainly caused by the voltage mismatch between phase legs and dc bus. This issue may exist in both single-phase and multi-phase MMC systems and can be eased by repetitive control based active harmonic suppression methods, which regulate the circulating current through legitimate...
For battery-based energy storage systems, cell equalizer is essential to improve battery life cycle and maximize capacity utilization. However conventional cell equalizers require long durations to accomplish cell balancing due to power rating and output current limitation. For high power application such as in green building, renewable energy and electrical vehicles, fast equalizing is vital. In...
Two-level energy management system is proposed and developed for coordination control of practical microgrid with distributed renewable sources and energy storages. A SCADA system has been developed to provide real time information of network information and individual components and to control operation of individual inverters and converters in order to achieve smooth and quick system operating mode...
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.