Synthesis of the Battery Charging System of a Stand-Alone Electric Locomotive


The paper presents the synthesis of the battery charging system of an electric stand-alone locomotive. The traction converter as boost rectifier is used together with a dedicated control strategy in order to obtain the unity power factor on the grid. Two objectives, often contradic-tory, that can be tracked in the choice of the control mode for the PWM rectifier are highlighted: increasing the per-formance, in order to obtain a rectifier with the best power factor, the best-controlled load current, acceptable switch-ing frequencies for common power transistors, a stable op-eration of the control system, etc.; reducing the complexity and price of the converter by giving up certain elements of the control system, such as the multiplication circuit, the voltage loop, and the use of specialized integrated circuits. A patented structure which responds better to the require-ments and particularities of autonomous vehicles is used. In the control part, direct current control method is adopted and it was implemented by two control loops. The external loop is dedicated to charging current control and the inter-nal loop is dedicated to grid current control. In order to the performance determination, the entire system is analyzed under Simulink environment and the energetic perform-ances are determined. Also, the influence of switching fre-quency is analyzed. images