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Ilamparithi T.,Opal - RT Technologies | Nandi S.,University of Victoria | Subramanian J.,University of Victoria
IEEE Transactions on Industry Applications

A novel scheme to reliably monitor the condition of static and dynamic eccentricity (DE) faults in salient-pole synchronous machines (SPSMs) through the standard short-circuit test is proposed in this paper. The detection technique is based on offline current signature analysis that does not require machine disassembly. The procedure is unaffected by machine saturation or supply voltage harmonics. In this scheme, DE fault is monitored by exploiting the presence of inherent static eccentricity (SE), whereas SE fault monitoring is achieved using residual estimation technique. The proposed method is found to work for both star and delta-connected machines. Results obtained from an experimental three-phase 2-kW SPSM have been used to validate the proposed eccentricity condition monitoring method. © 1972-2012 IEEE. Source

Zhang F.,McGill University | Li W.,Opal - RT Technologies | Joos G.,McGill University
IEEE Transactions on Industrial Electronics

In this paper, an improved model predictive control (MPC) of the modular multilevel converter (MMC) with reduced computational burden is proposed. A mathematical model of the MMC system based on the sum and difference of arm voltages are derived. Instead of determining the switching state of individual submodule (SM), the voltage levels of MMC are considered as control options based on the assumption that the SM capacitor voltages are well balanced. The further reduction of calculation effort is realized by using the tolerance band of capacitor voltages. The proposed MPC has a hierarchical structure. The cost function taking into account the ac-side current control, circulating current elimination and arm energy balancing is presented. The optimal voltage level, selected by the cost function, provides the voltage reference for the pulse width modulation modulator. The SM capacitor voltage balancing is done using a separate control loop. The proposed control strategy is investigated using an MMC high-voltage direct current system with 200 SMs in each arm in real-time simulation and hardware-in-the-loop tests. The performance of proposed method is verified by both steady-state and transient-state operations. © 2016 IEEE. Source

Li W.,Opal - RT Technologies
IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society

Industrial modular multilevel converter (MMC) controllers usually implement the sub-module (SM) capacitor voltage balance control (VBC) in field-programmable gate array (FPGA) boards. Conventional VBC methods need to sort out the capacitor voltages, where the sorting algorithm would become too complex to be accommodated in FPGA if the SM number is large. A sorting-less VBC optimized for FPGA implementation is proposed and validated for half-bridge MMC in previous works. This paper continues the work and proposes a compatible VBC FPGA implementation for both half-bridge and full-bridge topologies. The proposed VBC is implemented in an FPGA based real time simulator and investigated in a full-bridge MMC STATCOM test system. The VBC for large MMC (1024 SM per valve) can be implemented in one Virtex 7 FGPA board with an execution cycle time of 250 nanoseconds. The performance is validated in steady states, transients, and fault conditions. © 2015 IEEE. Source

Li W.,McGill University | Joos G.,McGill University | Belanger J.,Opal - RT Technologies
IEEE Transactions on Industrial Electronics

Wind power generation studies of slow phenomena using a detailed model can be difficult to perform with a conventional offline simulation program. Due to the computational power and high-speed input and output, a real-time simulator is capable of conducting repetitive simulations of wind profiles in a short time with detailed models of critical components and allows testing of prototype controllers through hardware-in-the-loop (HIL). This paper discusses methods to overcome the challenges of real-time simulation of wind systems, characterized by their complexity and high-frequency switching. A hybrid flow-battery supercapacitor energy storage system (ESS), coupled in a wind turbine generator to smooth wind power, is studied by real-time HIL simulation. The prototype controller is embedded in one real-time simulator, while the rest of the system is implemented in another independent simulator. The simulation results of the detailed wind system model show that the hybrid ESS has a lower battery cost, higher battery longevity, and improved overall efficiency over its reference ESS. © 2010 IEEE. Source

Mehrjerdi H.,Hydro - Quebec | Ghahremani E.,Opal - RT Technologies | Lefebvre S.,Hydro - Quebec | Saad M.,University of Quebec | Asber D.,Hydro - Quebec
IET Generation, Transmission and Distribution

This study presents a secondary voltage control based on an optimisation algorithm to locate the control buses and regulate the voltage. Control buses are the buses where compensators will be installed on these buses to regulate voltage and avoid voltage violations. Firstly, partitioning algorithm using fuzzy C-means has been implemented on the power network. Partitioning techniques split the power system into regions to avoid the propagation of disturbances between regions by using local controllers. Then, a number of buses are labelled as control buses displaying the critical point for voltage control in eachregion. The control algorithm is a decentralised controller which tries to eliminate voltage violations in power system resulting from load variations and disturbances. The decentralised controllers are implemented using flexible AC transmission system (FACTS) devices such as static synchronous compensator (STATCOM). The methodology is applied to the IEEE 118- bus network. The results show the performance and ability of the partitioning algorithm and bus control selection to regulate the voltage and avoid propagation of disturbances between regions. © The Institution of Engineering and Technology 2013. Source

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