Bus Short-Circuit Detection Using Weak Charge Current Variation
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Solution Overview
Problem
Current bus short-circuit detection methods in power circuits are inefficient, leading to secondary damage and reduced service life due to high impulse currents and excessive heating, as they rely on pre-charge circuits that are restricted by wide voltage ranges and prone to errors in determining short-circuit states.
Innovation Solution
A bus short-circuit detection method and circuit that employs a weak electricity charge circuit to charge the bus when an abnormal voltage is detected, with a weak charge current detection circuit monitoring the charge current variation to determine if the bus is short-circuited, allowing the pre-charge circuit to start only when the bus is not in a short-circuited state, thereby preventing secondary damage and reducing the design margin of the pre-charge circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-charge circuit is used to detect bus short-circuit state, then the bus voltage can be detected before charging, but the impulse current becomes too large causing secondary damage and excessive heating
Solution Approach 1:
The charging process is divided into two distinct stages: weak electricity charge phase and strong electricity charge phase. The weak electricity charge circuit uses a current limiting resistor to provide a limited current for initial charging and detection, while the strong electricity charge circuit provides full power only after short-circuit-free operation is confirmed. This segmentation prevents excessive impulse current and heating during the detection phase while maintaining reliable short-circuit detection capability.
Solution Approach 2:
The weak electricity charge circuit performs preliminary charging and short-circuit detection before the strong electricity charge circuit is activated. By conducting the detection phase with limited current first, the system identifies potential short-circuits before full power is applied, preventing secondary damage that would occur if detection were performed with full power.
2Adaptability or versatility
If a pre-charge circuit is designed with wide voltage range consideration, then various short-circuit causes are covered, but the operational performance is degraded
Solution Approach 1:
The system dynamically switches between weak electricity charge mode and strong electricity charge mode based on the detected bus voltage and short-circuit status. The charging current is not fixed but adapts to the system state: limited current during detection phase, full current during normal operation phase. This dynamic adjustment maintains operational performance while covering wide voltage ranges.
Solution Approach 2:
The charging current parameter is changed based on the operational phase: a limited current parameter is used during the weak electricity charge phase for safe detection, while a full current parameter is used during the strong electricity charge phase for optimal performance. This parameter change allows the system to maintain both adaptability across voltage ranges and high operational performance.
3Productivity
If strong voltage is applied for first-time power-on, then the bus can be charged, but the back-end circuit may suffer secondary damage from excessive impulse current
Solution Approach 1:
The weak electricity charge circuit acts as a cushioning mechanism before the strong electricity charge circuit is activated. The current limiting resistor provides a protective buffer that limits impulse current during the initial power-on and detection phase, preventing secondary damage to back-end circuits. Only after confirmed safe operation does the system remove this cushioning and enable full power charging.
Data Source
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AI summary
Disclosed is a bus short-circuit detection method and circuit, a storage medium and a processor. The method includes that: a weak electricity charge circuit is started in a case that a strong voltage detection circuit detects that a bus voltage of a unit is abnormal before the bus voltage is charged, wherein the weak electricity charge circuit is configured to charge the bus; charge current variation of the weak electricity charge circuit is detected; and a pre-charge circuit is started in a case that the charge current variation indicates that the bus is not in a short-circuited. The technical problem that, a detection circuit detects the bus short-circuit to cause that a rear-end circuit is not safe, is solved.