Capacitor Discharge Control Using Alternator Power in Vehicles
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Solution Overview
Problem
Existing vehicle systems require a dedicated power supply for capacitor discharge control, leading to increased size and complexity of the electric power conversion device, which degrades marketability and complicates control systems.
Innovation Solution
A vehicle configuration that uses an electronic control unit to operate the engine and alternator to supply power for capacitor discharge control without a dedicated power supply, utilizing existing alternator power to ensure reliable discharge of residual electric charges during potential collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated power supply is added inside the electric power conversion device for capacitor discharge control, then the reliability of discharge control is improved, but the device size and complexity increase
Solution Approach 1:
The existing alternator, originally designed for normal vehicle operation, is made to serve a dual function: it acts as both the normal power generation device and a backup power supply for capacitor discharge control. When a collision is detected, the ECU activates the alternator to provide power to the discharge control device, eliminating the need for a separate dedicated backup power supply and reducing overall system complexity.
Solution Approach 2:
The system uses its own existing components (engine and alternator) to serve the backup power supply function. Instead of adding an external backup power source, the vehicle's existing power generation capability is leveraged to discharge the capacitor after collision, making the system self-sufficient and reducing part count.
2Reliability
If the engine is operated in advance to supply power for capacitor discharge control, then the availability of power for discharge is improved, but unnecessary engine operation and energy consumption occur
Solution Approach 1:
The ECU detects collision possibility in advance (using sensors like radar or accelerometers) and activates the alternator before actual discharge is needed. This preliminary action ensures power is available when required, but the system monitors collision status continuously and shuts down the alternator once collision is confirmed or discharge is complete, avoiding unnecessary prolonged operation.
Solution Approach 2:
The ECU continuously monitors collision detection signals and capacitor charge status to control alternator operation. When collision is detected, the alternator is activated; when discharge is complete or no collision is detected, the alternator is shut down. This feedback-based control ensures the engine/alternator operates only when necessary, minimizing energy consumption while maintaining reliability.
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 reliable and efficient discharge of residual capacitor charges without adding a new power supply, preventing unnecessary engine operation after discharge completion and maintaining system reliability.
Implementation Method 1
The alternator is configured to generate electric power using the power of the engine
Implementation Method 2
The capacitor is connected to the high-voltage power line. The electronic control unit is configured to perform control such that the capacitor discharges the residual electric charge
Data Source
AI summary
A vehicle includes an engine, a rotating electric machine, a high-voltage power line, a high-voltage battery, an inverter, a capacitor, an electronic control unit, a low-voltage battery, an alternator, and a low-voltage power line. The capacitor is connected to the high-voltage power line. The electronic control unit is configured to control the engine such that the engine is operated and the alternator supplies electric power to the low-voltage power line in a case where the possibility of the occurrence of a collision of the vehicle is detected. The electronic control unit is configured to perform control such that the capacitor discharges a residual electric charge in a case where the possibility of the occurrence of the collision of the vehicle is detected or in a case where the occurrence of the collision of the vehicle is detected.