Electric Motor Absolute Position Maintenance via Buffer Capacitor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric motors used as actuators face the challenge of losing their absolute position during critical operations, which complicates control and increases costs and complexity due to the reliance on external energy supplies and additional sensors.
Innovation Solution
Implementing an independent voltage supply using a buffer capacitor to maintain the count value of rotations, allowing the microprocessor to resume operation with a known absolute position without redefinition, even during voltage drops or resets, and ensuring reliable sensor operation by comparing the voltage with a threshold value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an absolute position sensor is used to detect the absolute position of the electric motor, then the absolute position can be detected, but the absolute position can be lost during a critical operation and the complexity of the control circuit increases
Solution Approach 1:
The system is divided into two independent parts: a simple rotation counting function that continues operating during critical events, and an optional absolute position sensor that can be deactivated. The count value is segmented into pre-fault and post-fault portions that are combined after the critical operation, eliminating the need for continuous sensor operation and reducing overall system complexity.
Solution Approach 2:
The counting unit serves dual purposes: it normally counts rotations for position control, and during critical operations when the sensor is deactivated, it automatically maintains the count value using residual energy from the buffer capacitor. The system serves itself by preserving position information without requiring active sensor input during fault conditions.
2Power
If the controller is supplied from an external energy supply, then the controller can operate, but during a critical operation the absolute position is lost
Solution Approach 1:
A buffer capacitor is pre-charged during normal operation from the external energy supply. When a critical operation occurs and the external supply fails, this pre-stored energy in the buffer capacitor immediately takes over to maintain the counting unit's operation, ensuring continuous position tracking without interruption or data loss.
Solution Approach 2:
The buffer capacitor acts as an energy cushion prepared in advance to absorb and compensate for external energy supply failures. This beforehand cushioning ensures that the counting unit maintains operation during critical operations, preserving the absolute position information even when the main power supply fails.
3Reliability
If the independent voltage supply is maintained to operate the sensor during critical operation, then reliable measurement results are obtained, but the voltage supply may become insufficient
Solution Approach 1:
The system operates in periodic cycles: during normal operation the external energy supply charges the buffer capacitor, and during critical operations the buffer capacitor provides energy. The controller periodically monitors the buffer capacitor voltage and compares it to a threshold, switching between energy sources as needed to maintain reliable sensor operation without wasting energy.
Solution Approach 2:
The system dynamically changes the voltage supply parameter by switching between the external energy supply and the buffer capacitor based on voltage threshold comparisons. When the buffer capacitor voltage drops below the threshold during critical operation, the system parameter changes to deactivate the sensor or switch energy sources, ensuring the sensor only operates when sufficient voltage is available.
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
This solution ensures immediate knowledge of the electric motor's absolute position post-critical operation, reduces complexity and costs, and avoids time delays in control by maintaining sensor reliability and eliminating the need for additional position sensors.
Implementation Method 1
a buffer capacitor (7) coupled to the current-carrying line (11)
Data Source
AI summary
A method for maintaining a detected absolute position of an electric motor operating as an actuator during a critical operation involves the electric motor (2) being controlled by a controller (1) which is supplied with energy from an energy source. In the method, with which an absolute value sensor can be omitted, the absolute position of the electric motor (2) is measured during the operation thereof, wherein rotations of the electric motor (2) are detected. The rotations are counted, and a count value is output to a microprocessor (3) of the controller (1) in order to actuate the electric motor (2), and in the event of a critical operation, the currently detected count value is maintained by means of an independent voltage supply (7).