Direct-current electrical systems integration on a hybrid skidder using a parallelized step-down power converter array

Abstract

This paper deals with the control of the direct-current to direct-current (DC/DC) energy conversion between high voltage and low voltage systems within a hybrid electric power-train structure intended to be used in articulated forestry tractor, also known as skidder. Electrical part of the hybrid power-train is modeled for the case of utilization of a parallel array of step-down (buck) DC/DC power converters as a bridge between the high and low voltage DC buses. Thus obtained models are used to derive the control laws for the primary-level (power converter voltage/current) control systems, and the secondary level (power allocation) control strategy, which are simulated within the MATLAB/SimulinkTMsoftware environment, and subsequently verified by means of laboratory experiments. Final results are also used to gain insights about the efficiency of the DC/DC conversion process and to formulate practical rules for parallelized DC/DC converter operation aimed at maximization of overall DC-to-DC power conversion efficiency.

Keywords

• Step-down DC–DC converter
• Power distribution system
• Hybrid skidder
• Efficiency analysis