Inverter Safe-Mode Control with Redundant Speed-Dependent Paths
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Solution Overview
Problem
Existing electric drive systems lack reliable methods to establish rotational speed-dependent safe operating modes, particularly in the event of a fault, due to insufficient or improperly evaluated rotational speed information, which can lead to dangerous voltage peaks, high electric currents, and undesired deceleration.
Innovation Solution
Implementing two redundant control paths with separate safety devices to determine and establish safe operating modes, such as active short-circuit or freewheeling, based on rotational speed, ensuring redundancy and reliability even in the presence of faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control path is used to establish safe operating modes, then the device complexity is reduced, but the reliability is insufficient due to potential faults in the control path
Solution Approach 1:
The control system is segmented into two independent control paths (first control path with first safety device, second control path with second safety device). Each control path independently determines rotational speed and establishes safe operating modes, ensuring that a fault in one path does not compromise overall system reliability.
Solution Approach 2:
The patent implements redundant control paths as a preventive measure against future faults. By having backup control paths ready before faults occur, the system can maintain safe operating modes even when one control path fails, cushioning against potential reliability issues.
2Object-affected harmful factors
If rotational speed information is insufficient or improperly evaluated, then the control simplicity is maintained, but dangerous voltage peaks and high electric currents occur
Solution Approach 1:
The safety devices continuously determine and evaluate rotational speed information, using this feedback to dynamically establish appropriate safe operating modes. This feedback mechanism ensures that rotational speed is properly evaluated to prevent dangerous voltage peaks and high electric currents.
Solution Approach 2:
The system performs preliminary determination of rotational speed by the safety devices before establishing safe operating modes. This preliminary action ensures that rotational speed information is adequately evaluated and processed before control decisions are made, preventing harmful effects.
3Ease of operation
If unsafe operating modes are established, then the ease of operation is maintained, but undesired deceleration occurs
Solution Approach 1:
The safety devices change operational parameters (safe operating mode selection) based on determined rotational speed values. By adjusting these parameters according to actual rotational speed conditions, the system maintains ease of operation while preventing undesired deceleration that would result from inappropriate mode selection.
Data Source
AI summary
The present invention relates to establishing a rotational speed-dependent safe operating mode. For this purpose, two redundant control paths are provided and are each designed to establish either an active short-circuit or a freewheeling mode as the safe operating mode. In this way, even if one control path fails, a rotational speed-dependent safe operating mode can still be fully established.