Load State Detection Circuit for EV High-Power Switch Fault Identification
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Solution Overview
Problem
Existing technologies for high-power switch devices in electric vehicles lack proactive fault detection, leading to potential dangers due to passive protection mechanisms that only activate after the device is powered on, failing to address issues like grounding short circuits and short-circuits before the device is powered.
Innovation Solution
A load state detection circuit comprising a detecting power supply, voltage sampling circuit, switch unit, and microcontroller that samples voltage at a voltage sampling point before connecting the load to the drive power supply, allowing for pre-power-on fault detection, including grounding short circuit and short-circuit identification using a voltage divider circuit and anti-reverse diodes to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive protection mechanisms are used that only activate after the device is powered on, then the device structure remains simple, but safety and reliability deteriorate due to inability to detect faults before power-on
Solution Approach 1:
The patent implements preliminary fault detection by connecting a detecting power supply to the load before the drive power supply is activated. The microcontroller controls a switch unit to establish a detection circuit that measures voltage at sampling points prior to power-on, enabling proactive identification of grounding short circuits and short-circuits. This preliminary action prevents faults from escalating while maintaining relatively simple circuit architecture.
2Reliability
If voltage sampling is performed before power-on using a detecting power supply, then fault detection capability is improved, but energy consumption increases due to additional power supply operation
Solution Approach 1:
The detecting power supply operates periodically rather than continuously. The microcontroller controls the switch unit to activate the detection circuit only when needed for fault checking, then disconnects it. This periodic operation enables comprehensive fault detection capability while minimizing energy consumption by ensuring the detecting power supply remains inactive during normal load operation.
3Reliability
If the detecting power supply remains connected after fault detection, then the detection circuit remains ready, but interference with normal load operation occurs
Solution Approach 1:
The detection circuit is designed to be dynamically controllable through the switch unit. The microcontroller activates the detecting power supply and voltage sampling circuit only during fault detection phases, then disconnects them before the drive power supply is activated. This dynamic switching ensures the detection circuit is ready when needed while preventing any interference with normal load operation by ensuring complete disconnection during power-on sequences.
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 safe and proactive fault detection before powering on the load, preventing potential hazards by disconnecting the load from the detecting power supply if no fault is found, thus ensuring the load is only powered on when safe to do so, improving safety and reliability.
Implementation Method 1
The voltage sampling circuit is configured to sample a voltage at the voltage sampling point, and output the voltage to the microcontroller
Implementation Method 2
The load state detection circuit further comprises a first voltage divider circuit, the switch unit is connected to a first terminal of the first voltage divider circuit
Data Source
AI summary
Disclosed are a load state detection circuit and method. A microcontroller is connected to a switch unit which is connected between a detecting power supply and a load to be tested. A voltage sampling point is formed at either terminal of the load to be tested, and the voltage sampling circuit is connected between the voltage sampling point and the microcontroller. The voltage sampling circuit is configured to sample a voltage at the voltage sampling point. The microcontroller is configured to connect the load to be tested and the detecting power supply by controlling the switch unit, and determine whether a fault exists in the load to be tested according to a received voltage at the voltage sampling point sampled by the voltage sampling circuit, before connecting the load to be tested with the drive power supply.