Bridge Rectifier Control With dv/dt Switch Blanking
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Solution Overview
Problem
Existing bridge circuits, particularly rectifier circuits, are susceptible to large current spikes due to disturbances such as arcing, lightning, and electrostatic discharge, which can damage switches and diodes, and existing solutions do not adequately address these issues.
Innovation Solution
Incorporating slope detectors and NOR gates in bridge controllers to measure the rate of change of input voltage and blank switches when the slope exceeds a predetermined value, preventing large current spikes by controlling MOSFET switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slope detectors and NOR gates are incorporated in bridge controllers to measure rate of change of input voltage and blank switches, then circuit reliability is enhanced and switches are protected from damage, but device complexity increases
Solution Approach 1:
The slope detector continuously monitors the rate of change of input voltage in advance of potential disturbances. When a high dv/dt condition is detected, the controller proactively blanks the switches before large current spikes can occur, preventing damage to switches and diodes rather than reacting after failure occurs.
Solution Approach 2:
The slope detector acts as an intermediary sensing element that detects voltage rate of change conditions and translates them into control signals for the NOR gates. The NOR gates then mediate between the slope detector output and the switch control, enabling precise blanking action. This intermediary approach allows complex protection logic to be implemented through modular components.
2Loss of energy
If switches are blanked during high input voltage disturbances, then cross-conduction is minimized and power consumption is reduced, but productivity decreases due to switch operation interruptions
Solution Approach 1:
The blanking action is applied periodically only when high dv/dt conditions are detected by the slope detector, rather than continuously. This allows normal switch operation during regular rectification cycles while providing protective blanking during disturbance periods. The periodic nature of AC input voltage combined with event-driven blanking minimizes impact on overall productivity while reducing energy loss during critical events.
Solution Approach 2:
The protection mechanism applies blanking locally only to the affected switch or switches experiencing high dv/dt stress, rather than blanking all switches in the bridge circuit. The slope detector can identify which specific switch is at risk and the NOR gate configuration enables selective blanking of only those switches, maintaining operation of other switches and thus preserving overall circuit productivity.
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
Prevents damage to switches and diodes by minimizing cross-conduction during high input voltage disturbances, reducing power consumption and enhancing circuit reliability.
Implementation Method 1
the slope detector is configured to measure a rate of change of an input voltage across the first input node and the second input node
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
One example discloses a bridge controller, including: a slope detector coupled between the first input node and the second output node; wherein the slope detector is configured to measure a rate of change of an input voltage across the first input node and the second input node; and wherein the bridge controller is configured to blank at least one of the first switch and the second switch if the measured rate of change exceeds a predetermined value.