| To meet the special requirements, the modern military mobile diesel generator set(MMDGS) has strict technical indexes in power quality, reliability, adaptalibity, concealmentperformance, etc. The technology of variable speed constant frequency (VSCF) is a hotresearch topic in the fields of aircraft/spacecraft power supply, ships power supply, newenergy power generation and so on. The technology of VSCF can improve the utilization ofenergy and power qualityeffectively, while reducing weight and volume of equipments. Thevariable speed constant frequency diesel generator (VSCFDG) based on technology of VSCFis very suitable to improve the performance of MMDGS, and is considered developing trendsof next generation of diesel generator sets. In order to meet the higher performancerequirements of MMDGS and to keep the leading technology advantage, this dissertationtakes the VSCFDG as the research object, and carries out the research works on controltechnology to improve performance of MMDGS. The dissertation is supported by a majormilitary equipment pre-research project of Architectural Engineering of General LogisticsDepartment of PLA.The control performance of VSCFDG mainly includes operating speed scheduling curvedesign and speed control, mechine-side converter control and grid-side converter control. Allthese control technologies determine the features and performance of VSCFDG, and directlyinfluence the main technical index. Based on the actual special requirements of MMDGS, thedissertation researched the architecture of control system and control technology of VSCF.Specially, this dissertation focused on the research of operating speed scheduling and controltechnology, structure and control technology of converter, control system optimization designand so on.In order to reduce the specific fuel consumption and the noise pollution, the operationspeed scheduling and speed stabilityare researched in this dissertation. Considered thefeatures of integrated generator and the operation laws of generator, the target speed curve ofVSCFDG is determined by experiments.This speed curve reflects the system efficiency, loadpower demand and system reliability.In order to improve the performance of speed controland the consistency of control in wide speed range, a novel hybrid fuzzy self-tuning PIDcontrol strategy is presented. The simulation and experiment results verified rationality of thestrategy, and this strategy could meet all the control requirements of VSCFDG. Comparedwith the traditional control strategy, this one has rapider response and better surge capability. In order to improve the adaptability for load and to impromve power quality of VSCFDG,and according to the instantaneous symmetrical components theory,a double close-loopcontrol strategy based on synchronous rotating frame compensating both positiveand negativesequences is given. This strategy improved the output voltage and output current, andsuppressed the effect of asymmetric load and nonlinear load.Inordertoimprovethesystem reliability, convenience and rapidity of maintenance, theentire control system is divided into several control subsystemsaccording to themodularization design. And a hierarchical distributed architecture of control system ispresented. Each subsystem deals a main control task, and all the subsystems are gathered asan integral system through internal bus. Considered the engineering requirements, the controlsubsystems are designedparticularly, and the redundancy techniques and multiple monitoringmethods are used in this dissertation.At the end of this dissertation, the operation control experiments are completed on theplatform of VSCFDG prototype. The partial control experiments results verified thatsubsystems and strategies meet all requirements of operation control. The system controlexperiments results verified that the system framework is rational and effective. In addition,the proposed scheme, strategy, experiments results have guiding significance for other smalland medium-sized power equipment as well. |
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