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.
High speed motors rotating at speeds above 10,000 rpm are gaining more attention nowadays for various high performance applications. High efficiency and reliability are demanded by the applications like centrifugal compressors, pumps, machine tools, drills, aerospace etc. This paper presents novel design and analysis of a high speed axial flux permanent magnet motor for high speed, low power applications...
Modular multilevel converter (MMC) is one of the recent developed converter for high power applications. However, the major drawback of this converter in variable speed drives is that the capacitor ripple voltage increases at lower speed, when the load torque remains constant. This ripple voltage can be reduced by reducing the dc-bus voltage at lower speeds, while the capacitor voltages are maintained...
Recently introduced Bi-directional Z-Source breakers [1] are capable of clearing the short circuit fault within a few microseconds. In this paper, various applications and protection requirements for Bidirectional Z-Source breakers are discussed. Detailed comparison between de-rated AC breakers and Z-Source breakers is discussed. Breaker design criteria are explained with the help of simulation results...
Renewable sources like solar photovoltaic (PV) are preferred to be operated at low voltages. This necessitates high voltage boosting when they have to be connected to the high voltage DC bus. Conventional DC-DC converters (eg. boost and buck-boost) offer high voltage gain at the cost of reduced efficiency. This paper proposes a novel method to integrate low voltage PV power to the high voltage DC...
For high PV penetration, grid ancillary services such as dynamic voltage support and low-voltage ride-through (LVRT) operation are recommended by network operators. This paper proposes an integrated controller for LVRT capability of a three-phase grid-tied PV system connected to a LV grid. Generally X/R ratio is low for LV grids, therefore the active power injection is given higher priority than the...
The major drawback of Modular Multilevel Converter (MMC) based variable speed drives is that the capacitor voltage ripple varies inversely with the output frequency. This voltage ripple can be reduced at lower operating frequency by injecting circulating current into its each arm. However, this circulating current increases the overall current rating of the converter. The voltage ripple can also be...
Future Pressurised Heavy Water Reactors (PHWRs) are expected to use Slightly Enriched Uranium (SEU), which can increase the nuclear burn-up by about three times compared to the current nuclear technology. High speed centrifuge rotating at speeds above 30 krpm is essential for uranium enrichment. This paper presents novel design and analysis of a high speed axial flux permanent magnet motor for centrifuge...
The problem of ever-increasing energy demand and depletion of conventional resources is well known. In order to meet this growing demand, residential rooftop Photovoltaic (PV) systems, which can cater to the household demand and also supply excess power to the grid, are being encouraged. In this paper, a two-stage transformerless single-phase grid-tied PV system for residential rooftop application...
This paper proposes a novel Unified AC-DC (UADC) microgrid. The power from ac and dc sources is distributed through the same line. A Universal AC-DC Converter (UADCC) is used to connect the loads to this grid. The synthesis of unified ac-dc voltage is discussed, followed by topology and control strategy of the UADCC. Simulation studies are carried out in MATLAB/SIMULINK and results for the same are...
DC distribution system with DC appliances offer more efficient use of limited energy resources. A BLDC mixer-grinder is a promising alternative to the presently used inefficient mixer-grinders. This work presents a simple, low-cost control strategy for a DC-operated mixer-grinder with three-phase BLDC motor. A compact BLDC motor-controller is designed and developed. The mixer-grinder having variable...
Hysteresis current control (HCC) based voltage source converters (VSCs) have several advantages like good dynamic response, over-current protection, insensitive to load parameter variation and ease of implementation. The application of HCC technique for two-level VSCs are well established and few modifications of the same are also reported to operate with variable or constant switching frequency in...
Active power decoupling (APD) topologies are well known for improving the reliability of a single-phase inverter by eliminating the need for electrolytic capacitors at the DC-link. In this paper, several APD topologies are analysed for grid connected PV application, where, the common mode leakage currents are one of the main concerns. It is found that few APD topologies can minimize these leakage...
Modified topologies of a Z-Source DC Circuit breaker with bi-directional power flow capabilities are introduced in this paper. Conventional Z-Source breaker (ZSB) topologies can provide protection for unidirectional power flow. Proposed topologies of bi-directional ZSB (Bi-ZSB) and bi-directional ZSB with coupled inductor (Bi-CZSB) can clear the fault in either direction of power flow. Both topologies...
The rms value of capacitor ripple current is one of the important parameters for capacitor selection in Modular Multilevel Converter (MMC) based medium voltage adjustable speed drives. In this paper, an expression for the rms value of ripple current of each submodule capacitor in MMC is derived analytically. The analysis reveals that like capacitor ripple voltage, the ripple current also increases...
Cascaded H-bridge multilevel inverters (CHB-MLIs) are well accepted for medium and high power grid connected photovoltaic (PV) applications. Independent MPPT and modularity are the advantages of these converters over the diode clamped and capacitor clamped MLIs. However, CHB-MLIs are associated with inter-module leakage current through the parasitic capacitor of PV panels even though an isolation...
Droop control techniques reported in the literature mainly use compensator based multi-loop feedback structure. To tune these compensators either trial method or inverter average model based complex compensator design method is used. It is cumbersome to tune these compensators especially when large number of inverters having different power ratings are present in the system. In this paper, two novel...
Cascaded multicell converter is proved to be an effective solution for medium voltage high power drives. Three-phase diode bridge rectifiers with complex transformer configuration are normally used in this converter, which do not have regenerative capability. Three-phase or single-phase pulsewidth-modulated (PWM) rectifiers are used at the front end to achieve regenerative capability and input power...
This paper proposes a novel automatic mode transition control strategy for multiple inverters to operate in grid-connected and islanded modes without communication. When grid is available, all the inverters operate in grid-tied current control mode and transfer available power to the grid. On grid failure, they automatically shift to conventional droop control mode and shift back to grid-tied current...
Optimization plays a crucial role to bring out a trade-off between the cost and efficiency of permanent magnet motors. Optimization algorithm coupled with analytical magnetic circuit analysis, is one such technique to improve the performance of a motor. However, the non-linear effects like saturation, cross-magnetization, etc. are cumbersome to be modelled analytically. In addition, the interdependency...
Bulk electrolytic capacitors are used in single phase inverters to reduce the ripple in dc link voltage which is due to the pulsating nature of the instantaneous power. The reliability of an inverter is limited by the lower lifetime of these capacitors. In addition, the switching devices also deteriorate the reliability, due to their significant failure rate. In order to improve the overall reliability...
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.