Door Lock Pre-Charge Circuit for Washer Motor Drive Inrush Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional washing machines rely on relays to close power supply circuits, which can lead to inrush currents that may damage components and cause lighting issues, and lack efficient pre-charging mechanisms for motor drives.
Innovation Solution
A door lock is used to close the power supply circuit pathway, enabling current to flow to the motor drive, with resistors limiting initial current and a relay bypassing the resistor once pre-charging is complete, eliminating the need for relays and managing inrush currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay is used to close the power supply circuit, then the circuit can be closed to supply power to the motor drive, but inrush currents occur that may damage components and cause lighting issues
Solution Approach 1:
The door lock is configured to close the power supply circuit pathway before the motor drive is fully activated, enabling a controlled pre-charge current to flow through the motor drive in advance. This preliminary action prevents sudden inrush currents by gradually charging the motor drive capacitors, thereby protecting components and reducing lighting flicker while maintaining system reliability
Solution Approach 2:
The door lock acts as an intermediary device between the power supply and the motor drive, controlling the circuit closure and current flow. By using the door lock's locked position as the triggering mechanism for circuit closure, the system mediates the power delivery process to avoid direct connection that would cause inrush currents, thus protecting components without compromising power supply capability
2Productivity
If a relay is used to close the power supply circuit, then the circuit can be closed to supply power, but the system lacks efficient pre-charging mechanisms for the motor drive
Solution Approach 1:
The door lock is designed to serve multiple functions: its primary function of securing the door is combined with a secondary function of closing the power supply circuit pathway. This multi-functionality enables the door lock to trigger both door securing and power supply circuit closure simultaneously, creating an efficient pre-charging mechanism without adding separate control devices or increasing circuit complexity
Solution Approach 2:
The patent merges the door locking function with the power supply circuit control function. By configuring the door lock to simultaneously perform door securing and circuit pathway closure, the system combines two functions into one device, achieving efficient pre-charging of the motor drive while simplifying the overall circuit configuration and reducing the number of separate components required
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 effectively pre-charges motor drives without inrush currents, reducing component damage and lighting issues, while eliminating the need for relays, thus enhancing operational safety and efficiency.
Implementation Method 1
the door lock, upon movement to the locked position, is configured to close a pathway of a power supply circuit electrically coupling the device to a power supply thereby enabling a current to travel from the power supply through a pre-charge circuit to the device
Data Source
AI summary
An appliance including a motor drive, a power supply circuit electrically coupling the motor drive to a power supply, a cabinet having an opening, a door for opening and closing the opening of the cabinet, and a door lock. When the door lock is in a locked position, the door lock is configured to secure the door and close a pathway of the power supply circuit thereby enabling a current to travel from the power supply through a pre-charge circuit to the motor drive.