Motor Control Device Current Threshold Operation Time
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Solution Overview
Problem
Conventional motor control devices face challenges in reducing costs and ensuring a wide safe operation region, particularly due to the high cost of temperature sensors and limited detection capabilities for overheating without temperature sensors.
Innovation Solution
A motor control device that detects electric current thresholds to determine operation time periods, allowing continuous operation within safe limits without the need for temperature sensors, thereby reducing costs and expanding the safe operation region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensors are used to detect overheating, then the reliability of overheat protection is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces the thermal detection system (temperature sensors) with an electrical detection system. Specifically, it uses current detection means to monitor motor current, and derives temperature information indirectly through the relationship between current and temperature. This substitution eliminates the need for physical temperature sensors while maintaining protection capability, thereby reducing manufacturing cost while preserving reliability.
Solution Approach 2:
The patent introduces current detection as an intermediary parameter to indirectly measure temperature. Instead of directly detecting temperature with sensors, the system uses current as a mediator that correlates with temperature conditions. The current detection means monitors current, and the control unit uses this information to infer temperature states and trigger protection when necessary, achieving temperature monitoring without direct thermal contact.
2Reliability
If temperature sensors are installed to ensure safe operation, then the safe operation region is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex thermal sensing hardware with simpler electrical current detection. The temperature sensor installation, wiring, and signal processing infrastructure is substituted with current monitoring circuitry that is already present in motor control systems. This reduces device complexity while maintaining the ability to define and enforce safe operation regions through current-based thermal protection.
Solution Approach 2:
The patent makes the control unit multi-functional by enabling it to perform both current control and temperature monitoring functions. The same control unit that manages motor operation also processes current detection signals to determine temperature conditions and execute protection logic. This consolidation eliminates the need for separate temperature sensing and processing subsystems, reducing overall device complexity while preserving safe operation capabilities.
3Ease of manufacture
If current detection and operation time control are implemented, then the manufacturing cost is reduced, but the measurement precision of temperature monitoring deteriorates
Solution Approach 1:
The patent implements feedback control where the control unit continuously monitors current detection results and adjusts operation time accordingly. The system establishes a relationship between current magnitude/duration and temperature rise, using feedback from current measurements to infer temperature conditions. This feedback mechanism compensates for the indirect measurement approach, maintaining adequate precision for protection purposes without requiring expensive direct temperature sensors.
Solution Approach 2:
The patent changes the measurement parameter from direct temperature to electrical current. Instead of measuring temperature directly with sensors, the system measures current and uses the known relationship between current and temperature (through I²R heating) to determine thermal states. This parameter transformation enables cost-effective manufacturing while providing sufficient precision for overheat protection by leveraging established electro-thermal relationships.
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 approach enables low-cost implementation while securing a wide safe operation region by controlling motor operation based on electric current thresholds, reducing the risk of overheating and maintaining performance.
Implementation Method 1
a motor control device that detects electric current thresholds to determine operation time periods
Data Source
AI summary
A motor control device includes an electric current detection result acquisition unit configured to acquire a result of detecting an electric current for operating a motor, an electric current determination unit configured to determine whether or not the electric current acquired by the electric current detection result acquisition unit is greater than or equal to a predetermined threshold value, an operation time setting unit configured to set an operation time period corresponding to the electric current when the electric current determination unit determines that the electric current is greater than or equal to the predetermined threshold value, and an operation control unit configured to perform control for causing the motor to be continuously operated for the operation time period set by the operation time setting unit.