| Electric traction drive system is the key and difficulty to the equipment of metro cars. At present, the traction drive system and crucial techniques of metro cars are still monopolized by foreign enterprises, which greatly hampers the development of civil urban rail transportation equipment. On sponsored by National Key Technologies R&D Program for the "11th Five-year Plan"-"Development of Energy Reclaiming Traction Power Supply System and Traction Drive System for Urban Rail Transportation", this paper focuses on the discussion of crucial techniques of traction converter, traction motor and the stability of electric traction drive system for metro cars, and then verifies the correctness of the theoretical research by amounts of simulations, ground tests and field trails.To address the feature and constraints of pulse-width modulation at low switching frequency, one hybrid PWM algorithm based on synchronous SVM and optimized synchronous SHE-PWM is proposed; the smooth transition technologies between multi-mode modulation are researched; the intergrated digital hybrid PWM technology based on FPGA is achieved, which is also compared with modulation strategies of foreign traction converter at all round; with the simulation and experiments, the effectiveness of proposed hybrid PWM strategy is verified.The pole distribution law of traction motor based on complex model is deduced and analyzed, based on this, the problem and limitation of the traditional discrete rotor flux observer in low switching frequency are researched; with design of discrete flux observer, the stability is discussed and the discrete error is analyzed with matrix ω-norm; The new discrete rotor flux observer based on stabilization in high speed region and phase compensation with low calculation frequency is established and compared with the proposed new high-order Euler discrete method in this paper; Based on analysis of the pole placement strategy for the closed-loop rotor flux observer and the comparison discussion of motor parameters sensitivity, the precision and robustness of dicrete observer are improved.Based on hybrid PWM, the double-mode control strategy combined vector control and scalar control is proposed, and then, the feedforward decoupled pre-control, the phase angle control, synchronization between PWM and motor control and smooth transition between double-mode control are emphatically analyzed; To improve the performance of torque control of traction motor, a better control timing and related time-delay compensating approach are proposed based on complex current closed-loop model and a real-time correction strategy of flux orientation based on q-axis rotor flux error is discussed.The active damping stability control of traction electric drive system and optimized design of DC-link LC filter are realized. A traction converter-traction motor system model is established, based on this, the system stability effect of DC-link filter parameters is analyzed in details; with the analysis of system input impendance, system stability is researched, along with the stability aera of traction electric drive, acting as reference to design and optimization of the DC-link filter; The small-signal model based on DC-Link of electric traction system is established, then the instability nature of DC-link negtive impedance is discussed; An active damping stability control strategy is proposed, and the design principle and value determination of key parameters for the control strategy are analyzed.At last, the completely independent traction converter of metro car is realized. Through the reciprocal power-fed ground testing system for traction drive and field trial on Guangzhou Metro, a lot of validation and assessment tests are finished, comprehensive test waveforms and data are acquired, and the scientific and feasibility of the above proposed crucial technologies and engineering practice methods for traction electric drive system control of metro cars are verified one by one.Figures:172, Tables:6, References:161.
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