Research Of High-power Permanent Magnet Brushless DC Motor Drive System

Due to high efficiency, excellent speed-adjustability, and high feasibility, thehigh-power Permanent Magnet Brushless DC Motor(PMBDCM)drive system has appliedin the domains as ships, aircrafts and so on, where the attention is firstly paid to the runningefficiency and feasibility of drive system. The equipments for high-power PMBDCM drivehave been developed in foreign countries. However, the technique concerned is kept tothemselves. In domestic, the research work is mainly focused on the fractional powerPMBDCM at present, and the work for high-power PMBDCM drive is just kicked on, somany problems exist in the design of high-power PMBDCM proper and the development ofPMBDCM drive system. In order to investigate the performance of one kind of high-power PMBDCM drivesystem, a 50kW multi-phase permanent magnet brushless DC sample motor is developed inthis dissertation. The sample motor is strictly referred to one high-power PMBDCM, andthe structure of drive system is also accorded to the high-power PMBDCM drive system.By dint of the sample motor drive system, this dissertation has expounded the operationprinciple, discussed the parameter choice and analyzed experimental data, and then somevaluable conclusions were drawn for the high-power PMBDCM drive system. Thedissertation is deployed as follows: Firstly, the operation principle of the high-power PMBDCM drive is introduced. ThePMBDCM drive system presented in this dissertation adopts thyristors as the operationpower electronics, and employs capacitor for commutation, so the drive system has aspecial operation manner and control scheme. By sorting out the running status, the triggercontrol rules is formulated and the trigger control scheme is optimized, which lay afoundation for the simulation of the PMBDCM drive, and so do with the development ofpractical drive system. Then, the commutation process of the PMBDCM drive is investigated, and the effectof relational parameters upon the commutation characteristics is sum up, thereafter thecriterion of the parameter choice for drive system is brought out. The criterion has beenverified by the sample drive system. The commutation investigation provides a theoreticsupport for the design of high-power PMBDCM drive. IIIIn order to predict the running characteristics of PMBDCM drive, two mathematicalmodel, electric circuit model and S-function model, for PMBDCM are presented in thisdissertation, the modeling principles and realization of each model under Matlab/Simulinkplatform are detail stated. The circuit model has high simulation efficiency, and is good atoptimizing the main circuit of the motor drive system, whereas the S-function model bringsa feasible approach to investigate the details characteristics of the PMBDCM proper. Thetwo models promote the research of high-power PMBDCM drive. The armature reaction of the sample motor is also discussed in this dissertation. Theanalysis shows that the equivalent magnet circuit is a feasible method to calculate thenon-load operation status, but fail to compute the load operation status. Further researchshows the stator yoke and stator tooth have serious affected the performance of PMBDCM,and high magnet stature is not suitable for the PMBDCM whose magnets are mounted intangent direction. The dissertation has also pay attention to the mechanical characteristics of PMBDCMfed by voltage inverter. The expressions deduced in last chapter dictate the mechanicalcharacteristics PMBDCM fed by voltage inverter is much softer than that calculateddirectly according to the resistor of stator windings. This conclusion gives a valuablereference to PMBDCM design. To sum up, through the research of the multi-phase permanent magnet brushless DCsample motor, we have accumulated the design experience for PMBDCM, and acquired theknowledge of such drive system, which conduces to the development and realization of theequipment for high-pow...