Auxiliary Battery Charging Path Selection in Electric Vehicles
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Solution Overview
Problem
In electric powered vehicles, when the auxiliary battery's output is reduced, it can lead to difficulties in initiating the charging system path, potentially causing the vehicle's electrical system to fail, as the power consumption by the DC/DC converter and main relay is high, and the auxiliary battery may not be able to supply the necessary power for system activation.
Innovation Solution
A power supply system with a main power storage device, a charge device, a sub power storage device, a first power converter, and a second power converter, where the control device selectively uses the first and second charge modes to charge the sub power storage device based on its output state, using the second power converter with a lower rated output when the auxiliary battery's output is low, and the external power supply as a source in external charging mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DC/DC converter and main relay are used to charge the auxiliary battery, then the charging path can be established, but the power consumption increases and the auxiliary battery cannot supply enough power for system activation
Solution Approach 1:
The patent dynamically selects between two charging paths based on the auxiliary battery's output state. When the auxiliary battery has sufficient output, the DC/DC converter charges it. When output is low, the system switches to the bidirectional power converter path that can charge the auxiliary battery without requiring high auxiliary battery output for activation, thus resolving the contradiction between establishing a charging path and minimizing power consumption.
Solution Approach 2:
The system monitors the output state parameter of the auxiliary battery and changes the charging path based on this parameter. By detecting whether the auxiliary battery output is above or below a threshold, the control device switches between different charging modes, ensuring reliable system activation while managing power consumption effectively.
2Use of energy by moving object
If the auxiliary battery output is reduced, then the power consumption during charging decreases, but the control device may not operate properly and the vehicle cannot run
Solution Approach 1:
The system performs preliminary detection of the auxiliary battery's output state before initiating charging. Based on this preliminary assessment, it pre-selects the appropriate charging path to ensure that the auxiliary battery will have sufficient voltage for control device operation after charging, thus preventing the contradiction between reducing power consumption and maintaining control device operation.
Solution Approach 2:
The control device continuously monitors the auxiliary battery's voltage and output state, using this feedback to determine the appropriate charging path. This feedback mechanism ensures that the auxiliary battery is charged to a sufficient level to maintain proper control device operation, resolving the contradiction between power consumption reduction and reliable control operation.
3Productivity
If the bidirectional power converter is used for charging, then the charging efficiency improves, but the device complexity increases
Solution Approach 1:
The bidirectional power converter is designed to perform multiple functions: it can convert power from the main battery to charge the auxiliary battery, and it can also operate in reverse during regenerative braking to charge the main battery. This multi-functionality justifies the added complexity by providing improved charging efficiency and versatile power management capabilities in a single integrated device.
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
This configuration ensures a reliable charging path for the sub power storage device using the main power storage device's electric power, even when the auxiliary battery's output is reduced, preventing electrical system failure and ensuring vehicle operation.
Implementation Method 1
a first power converter connected to a path between the main power storage device and the electric motor, and configured to convert the electric power from the main power storage device into the charging electric power for the sub power storage device
Implementation Method 2
a second power converter connected to a path between a connection unit for connection with the external power supply and the main power storage device, and configured to convert the electric power obtained by the second power conversion through the charge device into the charging electric power for the sub power storage device
Implementation Method 3
a main power storage device configured to store electric power input/output with respect to an electric motor that generates vehicle driving power
Data Source
AI summary
A charge device converting electric power from an external power supply into a charging electric power for a power storage device is configured to allow power conversion bidirectionally. An AC/DC converter of an external charging system converts AC power of a power line into a charging electric power for an auxiliary battery. A DC/DC converter of the vehicle running system converts the electric power from the power storage device into the charging power for the auxiliary battery. When charging of the auxiliary battery is requested, a control device selectively executes a first charge of converting the electric power of the power storage device by the DC/DC converter to charge the auxiliary battery, and a second charge of converting the electric power of the power storage device by a charge device and the AC/DC converter to charge the auxiliary battery, according to an output state of the auxiliary battery.