Battery Motor Start Control with Dynamic Current Limiting
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Solution Overview
Problem
Motors powered by batteries often experience voltage drops during start-up, risking battery collapse or failure to start due to weak batteries or misdimensioned wiring, which is undesirable, especially in movable applications like vehicle or boat refrigerators.
Innovation Solution
A method and control system that continuously monitor and compare the input voltage to a predefined minimum, stopping the motor and reducing the maximum current supply if it drops below this threshold, allowing time for recovery before retrying the start, ensuring the battery is protected and the motor is successfully started.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the battery delivers maximum power during motor start-up, then the motor can be started successfully, but the battery voltage drops and risks battery collapse
Solution Approach 1:
The patent implements dynamic current limiting where the maximum current (Imax) is adjusted in real-time based on battery voltage conditions. The electronic control unit continuously monitors battery voltage and dynamically reduces Imax when voltage drops below Vmin, transforming the static current limit into a dynamic parameter that adapts to battery state, thus preventing battery collapse while enabling motor start-up.
Solution Approach 2:
The patent changes the operating parameters of the battery-motor system by introducing voltage-threshold-based current adjustment. When battery voltage falls below the predefined minimum voltage (Vmin), the system automatically reduces the maximum current parameter (Imax) supplied to the motor, thereby changing the power delivery characteristics to protect the battery while still allowing motor operation.
2Reliability
If the battery is weak or wiring is misdimensioned, then voltage drop occurs during start-up, but the motor may not start at all
Solution Approach 1:
The patent performs preliminary monitoring of battery voltage before attempting motor start-up. The electronic control unit checks whether battery voltage is above the minimum threshold (Vmin) before enabling full current (Imax) to the motor. This preliminary action prevents start-up attempts that would cause excessive voltage drop, thereby ensuring reliable motor starting even with weak batteries or misdimensioned wiring.
Solution Approach 2:
The patent implements a feedback mechanism where the electronic control unit continuously monitors battery voltage and uses this information to adjust the maximum current (Imax) supplied to the motor. When voltage drops below Vmin, the feedback loop automatically reduces Imax, creating a closed-loop control system that adapts to battery conditions and ensures reliable motor start-up while preventing battery damage.
3Productivity
If current is continuously supplied to the motor, then the motor can start, but the battery may collapse due to excessive power demand
Solution Approach 1:
The patent applies partial action by supplying only the necessary current (up to Imax) required for motor start-up rather than continuous maximum current. The electronic control unit limits current to Imax when battery voltage is above Vmin, and reduces current when voltage drops below Vmin, providing just enough power for motor starting without excessive energy depletion that would cause battery collapse.
Data Source
AI summary
A method for starting a battery driven motor, wherein an input voltage is measured continuously. In case the input voltage becomes smaller than a predefined minimum voltage the attempt to start the motor is stopped and the maximum permitted current level to be supplied from the battery to an electronic unit of the motor is lowered before the next attempt. This is repeated until the input voltage is larger than the minimum voltage and the motor is no longer in start-up mode. The method protects the battery from collapsing. The method is suitable for starting battery driven motors for driving compressors. The number of attempted start-up sequences may be counted and on the basis of this it may be determined that the battery is weak or that the wiring is misdimensioned. Furthermore, a control system for controlling starting of a motor.