Interface issues of mining haul trucks operating on trolley systems

A typical mining facility uses off-road mining trucks to haul materials, such as coal, ore, and overburden from the pit to a stockpile where the material can be stored or processed. A conventional haul truck operates with diesel engine, adding considerable fuel expenses to the entire mining operation. Mining haul trucks are one of the most challenging applications of power electronics in vehicular systems. It is established that the use of inverter fed three-phase induction motors with vector control is the preferred solution to reach the required high starting torque and a good dynamic performance. In addition, the system is customized to meet the high shock and vibration limit and a special cooling system because the air has high dust level including conductive and corrosive materials. The objective of the mines is to achieve the movement of the highest possible payload per hour while minimizing operating costs over the lifetime of the machines. Operating the trucks with power from the overhead trolley lines, especially while going up on a grade significantly increases productivity, reduces fuel costs and qualifies as a green solution. This paper presents the overhead power systems interface issues of the trolley assisted haul trucks and their solutions through simulation study and field experimental results.