DC/DC Converter Power-Off Detection in EV Inverter Pre-Charge
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Solution Overview
Problem
Existing vehicle control devices for electric vehicles face challenges in detecting abnormalities where the power supply to the DC/DC converter is not normally stopped, leading to wasteful power consumption.
Innovation Solution
The vehicle control device includes a controller that determines if the input voltage detected by a voltage detector is lower than the input voltage at the time of inverter pre-charge completion, indicating abnormal power supply to the DC/DC converter, without requiring additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply to the DC/DC converter is not normally stopped, then the DC/DC converter continues to consume power from the low voltage battery, but this leads to wasteful power consumption and reduced system efficiency
Solution Approach 1:
The controller continuously monitors the input voltage of the DC/DC converter and compares it with the battery voltage to detect abnormal power supply conditions. When the input voltage is lower than the battery voltage, it indicates that the DC/DC converter is operating abnormally and consuming power unnecessarily. The controller then stops the power supply to the DC/DC converter, preventing wasteful energy consumption.
Solution Approach 2:
The patent replaces complex additional hardware detection systems with a software-based voltage comparison method. By using the existing voltage detector and controller to compare voltage levels, the system can detect abnormal power supply conditions without requiring additional sensors or hardware, thereby reducing system complexity while maintaining reliable detection.
2Reliability
If additional hardware is added to detect abnormal power supply to the DC/DC converter, then detection capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The existing voltage detector and controller are designed to serve multiple functions: they not only control the normal operation of the DC/DC converter but also detect abnormal power supply conditions by comparing voltages. This multi-functionality eliminates the need for separate detection hardware, reducing device complexity while maintaining reliable abnormal condition detection.
Solution Approach 2:
The DC/DC converter system performs self-diagnosis by comparing its own input voltage with the battery voltage through the existing control system. The controller uses the voltage information already available from normal operation to detect abnormal conditions, allowing the system to monitor itself without requiring external or additional detection hardware.
Data Source
AI summary
There is provided a vehicle control device including: an inverter that is configured to drive an electric motor; a DC/DC converter that is configured to step down a voltage output from a high voltage battery; a pre-charge circuit including a pre-charge switch; a voltage detector that is configured to detect an input voltage input to the inverter and the DC/DC converter; and a controller. When the input voltage is lower than the input voltage at the time when pre-charge of the inverter is completed, the controller is configured to determine that power supplied from a power supply of the DC/DC converter to the DC/DC converter is not normally stopped.