Converter Controller Abnormality Detection for Soft Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Soft switching converters in fuel cell systems face challenges in detecting abnormalities in auxiliary circuits, leading to potential element breakdowns and operational failures due to excessive switching losses and surge voltages.
Innovation Solution
A converter controller with a main voltage raising circuit and an auxiliary circuit, including a clamp diode and snubber capacitor, detects voltage thresholds to identify abnormalities and transitions to fail-safe operations, preventing element breakdowns by limiting current rates and adjusting gate resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If soft switching converter is used to decrease switching loss and switching surge, then switching loss and stress on power semiconductor device are reduced, but the auxiliary circuit becomes complex and requires abnormality detection mechanism
Solution Approach 1:
The patent applies preliminary action by detecting abnormalities in the auxiliary circuit before they cause catastrophic failures. The detection mechanism monitors the auxiliary circuit proactively, and the gate resistance adjustment prepares the system in advance to prevent breakdown by limiting current rates when abnormalities are detected.
Solution Approach 2:
The patent implements beforehand cushioning by adjusting the gate resistance value to limit the rate of change of current when an abnormality is detected. This cushioning effect prevents sudden voltage spikes and current surges that could cause element breakdown, allowing the system to continue operating in a degraded mode rather than failing completely.
2Reliability
If abnormality detection is implemented to prevent element breakdown, then system reliability is improved, but detection precision and timing are critical to avoid false positives and ensure early detection
Solution Approach 1:
The patent applies feedback by continuously monitoring the auxiliary circuit and using the detection results to adjust the gate resistance value. When an abnormality is detected, the system provides feedback to change the gate resistance, which in turn affects the current rate of change and prevents further abnormalities. This closed-loop feedback mechanism improves both detection precision and system reliability.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the gate resistance value based on the detected abnormality. The gate resistance is changed from a normal value to a larger value when an abnormality is detected, thereby changing the electrical parameters of the circuit to limit current rates and prevent element breakdown.
3Strength
If gate resistance is adjusted to limit current rate of change, then element breakdown is prevented, but switching speed and response time are reduced
Solution Approach 1:
The patent applies dynamics by making the gate resistance value changeable rather than fixed. The gate resistance is dynamically adjusted based on the operational state and detected abnormalities. During normal operation, a lower gate resistance enables faster switching speed. When an abnormality is detected, the gate resistance is increased to limit current rates and protect elements, thus optimizing both speed and durability at different times.
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 early and simple detection of auxiliary circuit abnormalities, preventing element breakdowns and ensuring safe operation by comparing voltage thresholds and adjusting operational parameters.
Implementation Method 1
a first series connecting member in which a clamp diode and a snubber capacitor are connected in series, the clamp diode and the snubber capacitor being connected in parallel with the main switch
Implementation Method 2
detecting means for detecting a voltage between both the ends of the snubber capacitor clamped by the clamp diode
Data Source
AI summary
There is disclosed a converter controller which can simply and early detect an abnormality of an auxiliary circuit constituting a soft switching converter. On turning off a first switching element, a controller detects a voltage between both the ends of a snubber capacitor and a voltage between both the ends of the first switching element, to obtain a difference voltage. The controller compares the obtained difference voltage with a voltage threshold value stored in a memory (not shown) to judge whether or not the difference voltage is larger than the voltage threshold value. When the difference voltage is smaller than the voltage threshold value, the controller judges that an auxiliary circuit is normal, to end processing, whereas when the difference voltage is not less than the voltage threshold value, the controller judges that a failure (an open failure) occurs in the auxiliary circuit, to shift to a fail safe operation, thereby ending the processing.