Power Storage Control Apparatus for Electric Vehicle Emergency Operation
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Solution Overview
Problem
Electric vehicles, particularly trains, are unable to move independently to a nearest power supply point during overhead wire power failures due to the inability of high-voltage auxiliary power supply units to operate without overhead wire voltage and the main motor being non-battery drivable, leading to occupation of tracks and reduced stopping position accuracy.
Innovation Solution
A power storage control apparatus combining a step-up/step-down chopper and a power storage device, which selectively uses power from overhead wires or the storage device to enable low-speed operation and provide high-voltage auxiliary power, controlled by a unit that switches between normal and emergency running states to maintain operation of auxiliary circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power from overhead wires is used, then the electric vehicle can operate at normal speed with full power, but the vehicle cannot move when overhead wire power supply fails
Solution Approach 1:
The system changes the voltage parameter by using a step-up/step-down chopper to convert between overhead wire voltage and battery voltage, enabling the battery to power the main motor in emergency mode while maintaining normal operation when overhead wires are available
Solution Approach 2:
The battery is designed to serve multiple functions: it acts as an auxiliary power source during normal operation and as a primary power source for the main motor during emergency operation, eliminating the need for separate emergency propulsion systems
2Speed
If a battery is used to power the main motor during emergency running, then the vehicle can move to the nearest power supply point, but the battery voltage is insufficient to drive auxiliary circuits requiring high voltage
Solution Approach 1:
The step-up/step-down chopper acts as an intermediary device that converts the low voltage from the battery to the high voltage required by auxiliary circuits, enabling both main motor operation and auxiliary circuit operation during emergency running
3Loss of energy
If regenerated power is absorbed just before stop, then energy efficiency is improved, but the stopping position accuracy is degraded
Solution Approach 1:
The control system dynamically adjusts the power absorption strategy based on real-time conditions, switching between absorbing regenerated power into the battery and using mechanical brakes to maintain stopping accuracy, optimizing both energy efficiency and position precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables electric vehicles to move at low speed to the nearest power supply point and maintain operation of auxiliary equipment during power outages, improving stopping accuracy and energy efficiency by effectively managing power storage and regeneration.
Implementation Method 1
a step-up/step-down chopper (31) including a first input/output portion that receives the power from the overhead wire via an input circuit (20A) and connected to an input portion of a CVCF inverter (21) for an auxiliary circuit, and a second input/output portion connected to the power storage device
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A power storage control apparatus of one embodiment of the present invention includes a step-up/step-down chopper (31), a contactor (12) and a control unit (100). The control unit (100) is configured to control the contactor (12) so as to make the contactor supply the voltage from the overhead wire to the input portion of the VVVF inverter (15) of the main circuit in a normal running state and supply the voltage of the power storage device to the input portion of the VVVF inverter (15) in the second running state, and control the step-up/step-down chopper so as to make the step-up/step-down chopper perform a step-down operation to charge the power storage device (32) in the first running state and perform a step-up operation to discharge the power storage device (32) and supply the power to the CVCF inverter (21) in an emergency running state.