Vehicle Power Source System Inrush Current Control
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Solution Overview
Problem
Conventional power source systems in electric vehicles face complexity and inefficiency when connecting multiple power storage devices with different output voltages, leading to potential inrush currents and increased configuration complexity.
Innovation Solution
A power source system with a first and second power storage device, a voltage conversion device, and switches controlled by a control device that closes the switches based on predetermined voltage conditions to prevent inrush currents and simplify the configuration, using a backflow prevention circuit to manage current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay switches with precharge functions are used to connect power storage devices with different output voltages, then inrush current can be prevented, but device complexity increases
Solution Approach 1:
The control device performs preliminary voltage detection before closing the relay switch. It detects the voltage of the second power storage device and compares it with the first power storage device voltage, then decides whether to close the relay switch based on the voltage difference. This preliminary action prevents inrush current without requiring complex precharge circuits.
Solution Approach 2:
The control device acts as an intermediary between the power storage devices and the relay switch. It mediates the connection process by detecting voltages, comparing them, and controlling the relay switch closure timing. This intermediary control simplifies the overall system configuration compared to using relay switches with built-in precharge functions.
2Power
If multiple power storage devices are connected in parallel to improve power supply capacity, then power output increases, but configuration complexity and potential harmful factors increase
Solution Approach 1:
The control device continuously detects the voltage of the second power storage device and uses this feedback information to control the relay switch. The feedback mechanism ensures safe parallel connection of power storage devices with different voltages, enabling power supply capacity expansion without proportionally increasing configuration complexity.
Solution Approach 2:
The system dynamically adjusts the connection state of the relay switch based on real-time voltage detection. The relay switch is closed only when voltage conditions are satisfied, allowing the system to adaptively manage multiple power storage devices. This dynamic control enables flexible power supply capacity adjustment while maintaining manageable configuration complexity.
3Ease of operation
If relay switches are used to connect power storage devices, then connection control is achieved, but potential harmful factors increase due to inrush current risks
Solution Approach 1:
The control device performs preliminary voltage detection and comparison before closing the relay switch. By detecting the voltage of the second power storage device and comparing it with the first power storage device voltage beforehand, the system ensures that the relay switch is only closed when voltage conditions are satisfied, thereby preventing inrush current while maintaining ease of connection control.
4Reliability
If output limit of first power storage device is restricted to prevent engine start, then power storage device protection is improved, but productivity decreases
Solution Approach 1:
The control device periodically detects the voltage of the second power storage device and adjusts the output limit of the first power storage device accordingly. When voltage conditions are not satisfied, the output limit is restricted to protect equipment; when conditions are satisfied, the restriction is released to enable normal vehicle operation. This periodic monitoring and adjustment resolves the contradiction between equipment protection and vehicle mobility.
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 solution allows for efficient and safe connection/disconnection of power storage devices, reducing configuration complexity and preventing inrush currents, thereby improving power supply efficiency and simplifying the system.
Implementation Method 1
a voltage conversion device (10), The voltage conversion device is configured to convert a voltage from the first power storage device
Implementation Method 2
The backflow prevention circuit may be configured to include a diode
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A second power storage device (BAT2) is electrically connected to a positive electrode line (PL3) and a negative electrode line (NL1), and electric power for generating a driving force is directly supplied to an inverter section (20). A converter section (10) supplies electric power received from the inverter section (20) to a first power storage device (BAT1). Because a backflow prevention circuit (35) is provided, the electric power is not supplied in the direction of the second power storage device (BAT2) at this point. A diode (D3) of the backflow prevention circuit (35) is connected between a system main relay (SMR2) and the connection node of a positive electrode line (PL2) on the positive electrode line (PL2) branching off from the positive electrode line (PL3) and connected to the second power storage device (BAT2). The diode (D3) controls the flow of a current from the positive electrode line (PL3) side toward the second power storage device (BAT2).