Detecting DC Motor Line Interruption via Unified Driver and Computed Parameters
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Solution Overview
Problem
In drive systems with two parallel-connected DC motors mechanically coupled to a part that is to be driven, identifying electrical line interruptions is challenging due to mechanical coupling, which causes the remaining active motor to become overloaded, and existing solutions require multiple current measuring apparatuses, increasing complexity and cost.
Innovation Solution
A method and arrangement that utilize a single driver for both DC motors, employing a measuring device with rotational speed, current, and voltage determination apparatuses to calculate a motor parameter using the formula kω=UKL-ISum^2·Raω, allowing for inference of line interruptions with reduced hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate driver stage is provided for each electric motor to enable independent current measurement, then line interruption can be identified, but device complexity and cost increase
Solution Approach 1:
The patent combines the driver stages for both DC motors into a single integrated driver unit. Instead of providing separate driver stages for each motor, the invention uses one driver that can control both motors, thereby reducing device complexity while maintaining the capability to detect line interruptions through current comparison
Solution Approach 2:
The single driver stage is designed to perform multiple functions: it controls both DC motors and enables line interruption detection for both motors through unified current measurement. This multi-functional approach eliminates the need for separate dedicated driver stages for each motor
2Measurement precision
If current measuring apparatus is provided in each motor feed line to identify line interruption, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the current measurement functions into a single measurement point at the common feed line before the motors diverge. By measuring the total current once and using computational evaluation to determine individual motor currents, the invention eliminates the need for multiple separate current measuring apparatus while maintaining detection accuracy
Solution Approach 2:
The invention replaces physical current measuring apparatus in each motor line with a computational evaluation system. Instead of using multiple hardware sensors, the system uses a single current measurement combined with mathematical calculations to detect line interruptions, thereby reducing hardware requirements and manufacturing costs
3Loss of information
If motor speed is monitored to detect drive system status, then operational information is obtained, but line interruption cannot be reliably identified due to mechanical coupling
Solution Approach 1:
The patent replaces mechanical speed-based detection with electrical current-based detection. Instead of relying on motor speed signals that are affected by mechanical coupling, the system measures electrical current in the motor feed line, which provides direct information about motor operation status and line integrity independent of mechanical connections
Solution Approach 2:
The invention uses current measurement as an intermediary parameter to detect line interruptions. Rather than directly observing motor operation through speed signals that are confounded by mechanical coupling, the system uses current measurement combined with computational evaluation to indirectly but reliably detect line interruptions
Data Source
AI summary
The invention relates to an arrangement for identifying an electrical line interruption during operation of a drive system (20), which comprises two parallel-connected DC motors (21, 41), which are mechanically coupled to one another by means of a part that is to be driven, a driver for driving the two parallel-connected DC motors (21, 41) and a measuring device for detecting different electrical variables of the drive system (20). The measuring device comprises a rotational speed determination apparatus (32) for determining the rotational speed of the two DC motors (21, 41) and for supplying a piece of rotational speed information representing the rotational speed. The measuring device further comprises a current measuring apparatus (27; 28) for determining a summation current flowing in the two DC motors (21, 41) and for supplying a piece of current information representing the summation current and a voltage determination apparatus (60; 61) for determining the terminal voltage of the two DC motors (21, 41) and for supplying a piece of voltage information representing the terminal voltage. A computation unit (70) is designed to ascertain a motor parameter (kω) for the drive system (20) from the voltage information, the current information and the rotational speed information and to compare said motor parameter with a setpoint value (kω_set) of the motor parameter (kω), wherein the presence of a line interruption to one of the two DC motors (21, 41) can be inferred from the result of the comparison.