Patent ID: 8174225

Claim:
A method for supplying electrical power to at least one mining excavator, each mining excavator comprising at least one electrical motor, the at least one mining excavator comprising a cyclic load, the method comprising: receiving alternating-current electrical power from an electrical power grid; converting the alternating-current electrical power to direct-current electrical power; feeding a direct-current link with the direct-current electrical power; charging an electrical energy storage unit with electrical power drawn from the direct-current link; supplying electrical power to the cyclic load from only the direct-current link when the electrical power drawn by the cyclic load is less than or equal to an upper limit; and supplying first electrical power to the cyclic load from the direct-current link and second electrical power to the cyclic load from the electrical energy storage unit when the electrical power drawn by the cyclic load is greater than the upper limit, wherein the first electrical power is less than or equal to the upper limit.