Phase Loss Detection in Electric Converter Units
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Solution Overview
Problem
Existing conveyor systems, such as elevators and escalators, face challenges in reliably detecting loss or undervoltage conditions of phase in electric converter units, leading to unstable operation and potential safety hazards.
Innovation Solution
A method for detecting loss or undervoltage conditions by determining extremum values of phase voltage and comparing them to threshold values, while also integrating phase current ampere-second balances, to ensure reliable detection across various operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If simple phase loss detection methods are used, then device complexity is reduced, but reliability of phase loss detection deteriorates
Solution Approach 1:
The detection method is divided into multiple independent stages: voltage extremum detection, current ampere-second balance detection, and integrated determination logic. Each stage processes specific parameters independently, allowing the system to achieve high reliability through multi-stage verification without requiring a single complex detection mechanism.
Solution Approach 2:
The patent transitions from single-parameter detection to multi-dimensional detection by incorporating both voltage extremum analysis and current ampere-second balance analysis. This dimensional expansion enables more reliable phase loss detection under various operating conditions, including motor regeneration scenarios where single-parameter methods fail.
2Measurement precision
If detection methods are simplified, then ease of operation is improved, but measurement precision of phase voltage and current deteriorates
Solution Approach 1:
The detection system utilizes the motor's own operating parameters (phase voltages and currents) already present in the drive system. By processing these existing signals through the extremum detection and ampere-second balance methods, the system achieves precise phase loss detection without requiring external sensors or additional measurement equipment, thereby maintaining ease of operation.
3Adaptability or versatility
If conventional detection methods are used, then device complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The detection method is designed to function universally across different operating conditions including motor acceleration, deceleration, and regeneration modes. The combination of voltage extremum detection and current ampere-second balance analysis creates a universal detection mechanism that adapts to various operational scenarios without requiring mode-specific detection logic, achieving multi-functionality in a single system.
Data Source
Figure 1A
Figure 1B~2
Figure 3A~3C
AI summary
A method for detecting a loss or an undervoltage condition of phase of an electric converter unit (30), characterized in that the method comprises: determining (410) an extremum value, such as a maximum and/or a minimum value, of a phase voltage of the electric converter unit (30) for at least one fundamental period of the phase voltage, and comparing (420) the extremum value to a first threshold value, and if, based on the comparison, a first threshold criterion related to the first threshold value is satisfied, then determining (430) the loss or the undervoltage condition of phase.