Electrical energy storage system for traction power supply

摘要

An energy storage system for connection to a traction power supply that provides power to an electric vehicle. The energy storage system includes a power controller that controls a DC-DC converter to transfer electrical energy from the traction power supply to electrical energy storage when the train is braking. The power controller also controls the converter to transfer electrical energy from the electrical energy storage to the traction power supply when the train is accelerating. The controller slows the rate of energy transfer when upper and lower voltage boundary limits of the electrical energy storage are approached, respectively.

主权项

1. An energy storage system for connection to a traction power supply that provides power to an electric vehicle, the energy storage system comprising:
(a.) a buck-boost DC-DC converter for connection to the traction power supply; (b.) an electrical energy storage; (c.) a storage bus connecting the electrical energy storage to the converter; and (d.) a power controller communicably connected to the converter and being operable in a regeneration mode when the vehicle is braking and in an assist mode when the vehicle is accelerating; wherein when the power controller is in the regeneration mode, the power controller controls the converter to transfer electrical energy from the traction power supply to the electrical energy storage; wherein when the power controller is in the assist mode, the power controller controls the converter to transfer electrical energy from the electrical energy storage to the traction power supply; and wherein the controller slows the rate of electrical energy transfer between the traction power supply and the electrical energy storage when upper and lower voltage boundary limits of the electrical energy storage are approached, respectively, and wherein the power controller comprises a first controller that works to reduce the difference between the voltage of the traction power supply and a reference voltage, a second controller that works to produce a constraint boundary based on the difference between the storage bus voltage and a maximum bus voltage utilizing a gain of the second controller, and a dynamic saturator operable to receive an output from the first controller and to bound the output to upper and lower saturation levels, the upper saturation level being the output of the second controller.