Inverter Current Interruption Control for Electric Rotating Machine Voltage Faults
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Solution Overview
Problem
Existing control systems for electric rotating machines, such as ISGs, face challenges in distinguishing between voltage decreases caused by the machine itself and those caused by external factors, leading to unnecessary power running and power generation losses during protection processes.
Innovation Solution
A control apparatus that determines whether a power-supply voltage decrease is caused by the electric rotating machine or external factors, using threshold values and interruption counting to selectively release current flow interruptions, thereby preventing unnecessary protection processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection process is performed based on power-supply voltage decrease, then the switching elements are protected from damage, but the power running and power generation functions are unnecessarily lost when the voltage decrease is caused by external factors
Solution Approach 1:
The patent introduces multiple threshold values (first threshold, second threshold, third threshold) to differentiate between normal voltage fluctuations and actual short circuit abnormalities. By changing the parameter of voltage threshold levels, the system can distinguish between external factors causing voltage decrease and internal faults requiring protection, thus avoiding unnecessary loss of power functions while maintaining switching element protection
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors power-supply voltage and compares it against multiple thresholds. When voltage decreases below the first threshold, the system performs protection process; when voltage recovers above the second threshold, the system can restore functions based on the third threshold comparison. This feedback loop enables intelligent decision-making to balance protection and functionality
2Reliability
If the protection process is performed whenever power-supply voltage decreases, then switching element damage is prevented, but system stability is reduced due to repeated unnecessary interruptions
Solution Approach 1:
The patent uses multiple voltage thresholds (first, second, and third thresholds) to create a staged response system. Instead of a single binary protection trigger, the system evaluates voltage against multiple parameter levels, allowing it to distinguish between transient fluctuations and genuine faults. This multi-parameter approach reduces repeated unnecessary interruptions while maintaining effective protection
Solution Approach 2:
The patent establishes predetermined threshold values before operation to guide protection decisions. By having pre-set first, second, and third thresholds, the system can immediately evaluate voltage conditions without complex real-time analysis, enabling stable and consistent protection decisions that prevent repeated unnecessary interruptions
Data Source
AI summary
A control apparatus includes a first determination section determining whether a power-supply voltage has decreased below a first threshold value, an interruption section interrupting a current flow to an inverter if the voltage has decreased below the first threshold value, a second determination section that determining whether the power-supply voltage has increased above a second threshold value, an interruption releasing section releasing the interruption based on the fact that the voltage has increased above the second threshold value, a count section counting the number of interruptions, a limiting section determining whether the decrease in the power-supply voltage is caused by a first factor of an electric rotating machine or a second factor, and limits the counting if the decrease in the power-supply voltage is caused by the second factor, and a third determination section determining whether the interruption is allowed to be released based on the number of interruptions.