Electric Working Machine Motor Control via Voltage Detection
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Solution Overview
Problem
Electric working machines continue to drive motors after the power supply plug is removed from the AC power source, causing user discomfort and potential safety hazards due to prolonged capacitor discharge.
Innovation Solution
Incorporating a voltage detector and controller that interrupt motor energization when the AC power source is disconnected, and a discharger to rapidly or gradually release capacitor charge when power is interrupted, ensuring the motor stops and preventing electric shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a capacitor is used to smooth the AC voltage for driving the motor, then the motor can continue to operate after power interruption, but this causes user discomfort and safety hazards due to prolonged motor operation
Solution Approach 1:
The voltage detector detects the AC voltage status before the power interruption occurs, and the controller proactively interrupts motor energization and activates the discharger to discharge the capacitor in advance, preventing the harmful effect of prolonged motor operation after power loss
Solution Approach 2:
The voltage detector acts as an intermediary between the power source and the motor control system, providing early warning of power status changes so the controller can take preventive action to interrupt motor operation and discharge the capacitor before the harmful discharge phase begins
2Productivity
If the motor is allowed to run on capacitor discharge after power interruption, then the motor continues to work, but this creates potential electric shock hazards and prolonged operation issues
Solution Approach 1:
The controller applies preliminary anti-action by interrupting motor energization and activating the discharger before the capacitor discharge phase begins, counteracting the potential harmful effects of uncontrolled motor operation and electric shock hazards
3Ease of operation
If no voltage detection and control system is added, then the device remains simple, but the motor cannot be stopped when power is interrupted causing user discomfort
Solution Approach 1:
The patent replaces complex mechanical interlocking systems with an electrical detection and control system using voltage detection and electronic switching, achieving more reliable and responsive control with simpler overall system architecture
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
Prevents motor operation when the power plug is removed, enhancing user experience and safety by immediately stopping the motor and discharging capacitor energy, thus eliminating user discomfort and reducing the risk of electric shock.
Implementation Method 1
a power supply portion that generates a DC voltage to drive a motor by rectifying an AC voltage supplied from an external AC power source
Implementation Method 2
smoothing the AC voltage by a capacitor
Data Source
AI summary
An electric working machine of an example of the present disclosure includes: a motor; a power supply portion; a controller; and a voltage detector. The power supply portion generates a DC voltage to drive the motor by rectifying an AC voltage supplied from an AC power source and smoothing by a capacitor. The controller controls energization of the motor. The voltage detector detects the AC voltage. The controller is configured to interrupt the energization when the voltage detector does not detect the AC voltage.