| This paper focuses on Dual-Source trolley bus power supply system which has broad application prospect but is rarely studied. Two respects of the power supply system, control strategy and system stability are studie. The main focuses of this paper are as following;(1) Typical load characteristics in the trolleybus power system is analyzed. And According to the theory of hierarchical control, layered energy management strategy of power supply system is proposed.(2) Based on converter circuit topology and control strategy in the power supply system, derived the linearized small signal model of PWM rectifier, off-board charger and driving load.(3) Lyapunov method which is widely used in small signal stability analysis is applied to investigating the stability of single converter and the whole power supply system.For the energy management of power supply system, upper and lower energy management strategies are proposed for the trolleybus power system specific load. For the existing power supply system, energy management of vehicle level is proposed to reduce the special load effect on the power station. For improved power supply system, energy management of power sation is proposed to improve the reliability of power supply system further, which could serve as a template for the large-scale application of dual-source trolleybus.The small disturbance stability of DC power supply system is discussed in this system. First of all, the state space method is adopted to establish the dc power supply system of converter. Based on this, state space equation of DC power supply system is obtained, and the eigenvalues of the system state matrix, which will be used to determine the small disturbance stability of this system, are calculated. And the trajectory of eigenvalues, as the converter control parameter varies, is derived, then the effect of control parameters on the stability of power system can be analyzed. Examples show that when the control coefficient increases to a certain value, eigenvalues with positive real part occur, which means the system is unstable. In order to analyze the transient stability of power supply system, domain simulation is carried out based on these examples, bus voltage curve with different values of the control coefficient is obtained when load surges. On one hand, the simulation results verify the results of stability analysis,that is, when the control coefficient is too large, the system will deviate from the original stable work point:On the other hand, it shows that as long as the control system is stable, the larger the control factor, the better the voltage control effect. Therefore, the reasonable selection of control parameters of current transformers is very important for ensuring the stable performance of the dc power supply system.These results can be applied to similar topology rail transport, electricity and other fields, and have broad application prospects. |
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