Simplified Topology For Trolley Assist-Capable Electric Drive Truck
AssigneeCaterpillar Inc.
InventorLewei Qian
Life of this patent
Estimating the term…
Abstract
A trolley assist-capable electric drive truck includes a DC link with first, second and third contactors that may be opened and closed in different configurations to operate the truck in different modes. In a normal propel mode, the three contactors are open and electrical power is routed from an onboard electrical power source to electric propulsion motors. During normal retard mode, the three contactors are closed to route electrical energy generated by the electric propulsion motors through a grid resistor of the DC link. In a trolley mode, the first and second contactors are closed, but the third contactor is open, and electrical power is routed from the trolley lines to the motors for propulsion, or in a reverse direction for retarding the truck.
Claims11
A trolley assist-capable electric drive truck comprising:
- a frame;
- a plurality of ground engaging elements coupled to the frame;
- an onboard electrical power source attached to the frame and including an internal combustion engine mechanically coupled to an electrical power generator;
- at least one electric propulsion motor coupled to the ground engaging elements;
- a circuit electrically connecting the electrical power generator to the electric propulsion motor;
- a pantograph supported on the frame and movable between a trolley line engagement configuration and a stowed configuration;
- a DC link electrically connected between the circuit and the pantograph, and including a first contactor electrically separating a positive direct current conductor from a positive pantograph conductor;
- a second contactor electrically separating a negative direct current conductor from a negative pantograph conductor;
- the positive direct current conductor being electrically separated from the negative direct current conductor by the first contactor, a third contactor, a grid resistor and the second contactor;
- and each of the first, second and third contactors being changeable between an open circuit configuration and a closed circuit configuration.
A trolley DC link comprising:
- a first contactor electrically separating a positive direct current conductor from a positive pantograph conductor,
- a second contactor electrically separating a negative direct current conductor from a negative pantograph conductor,
- the positive direct current conductor being electrically separated from the negative direct current conductor by the first contactor, a third contactor, a grid resistor and the second contactor;
- and
- each of the first, second and third contactors being changeable between an open circuit configuration and a closed circuit configuration.
A method of operating a trolley assist-capable electric drive truck, comprising the steps of:
- propelling the truck in a normal propel mode by opening a first, second and third contactor of a DC link and routing electrical energy from an onboard electrical power source to an electric propulsion motor coupled to ground engaging elements;
- propelling the truck in a trolley propel mode by closing the first and second contactors and opening the third contactor and routing electrical energy from a pantograph through the DC link to the electric propulsion motor;
- and
- retarding the truck in a normal retard mode by closing all of the first, second and third contactors and routing electrical energy from the electric propulsion motor through a grid resistor of the DC link.
Dependencies are inferred from the claim text.