Refrigerator Sequential Motor Control to Reduce Peak Power Demand
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing refrigerators require high power to automatically open and close multiple doors due to the need for rapid motor operation to overcome pressure differences, leading to inefficiencies and increased power requirements.
Innovation Solution
A refrigerator system with a processor that controls the order and timing of door opening and closing, using a first motor to open one door and a second motor to open the second door after a threshold time, with optimized current usage and RPM control to minimize power consumption, and adjusts operations based on door weights and thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If multiple motors are driven simultaneously to open multiple doors, then the door opening function is achieved, but the power supply capacity requirement increases significantly
Solution Approach 1:
The system opens doors in a predetermined sequence rather than simultaneously. The processor controls the first motor to open the first door, then after a first time interval when inrush current has decreased, starts the second motor to open the second door. This preliminary sequencing of actions reduces the peak power requirement.
Solution Approach 2:
The door opening process is divided into periodic stages with time intervals between them. The system operates the first motor for a period, waits for the inrush current to subside (first time interval), then operates the second motor. This periodic operation pattern prevents simultaneous power demands.
2Speed
If motors rotate rapidly to overcome pressure difference, then the door opens quickly, but the inrush current increases
Solution Approach 1:
The system allows the first motor to start and its inrush current to subside before starting the second motor. The processor waits for the first time interval, monitoring when inrush current drops below a threshold, before activating the next motor. This preliminary timing coordination manages current peaks.
Solution Approach 2:
The system incorporates time intervals as a cushioning mechanism between motor startups. By waiting for the first time period after the first motor starts before initiating the second motor, the system cushions against the cumulative effect of simultaneous inrush currents from multiple motors.
3Productivity
If all doors are opened simultaneously, then the operation is completed faster, but the power supply device capacity must be increased
Solution Approach 1:
The system establishes a preliminary sequence for door opening operations. The processor is configured to start the first motor, wait for the first time interval (when inrush current decreases), then start the second motor. This predetermined sequencing achieves efficient operation without requiring excessive power capacity.
Solution Approach 2:
The system dynamically adjusts the timing between motor operations based on real-time current conditions. The processor monitors when inrush current falls below a threshold and adjusts the startup timing of subsequent motors accordingly, optimizing the balance between speed and power requirements.
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
Enables efficient opening and closing of multiple doors with minimal power supply, reducing energy requirements and operational complexity in a limited space.
Implementation Method 1
a large power is necessary due to a difference in pressure between the inside and the outside of a refrigeration compartment
Implementation Method 2
it is necessary to provide a motor providing a power so that the doors rotate
Data Source
AI summary
A refrigerator and a controlling method thereof are provided. The refrigerator includes a main body including first and second doors, a first motor for opening the first door and a second motor for opening the second door, and a processor configured to, based on a user command for opening the door being obtained, start driving the first motor to open the first door, and after a first time from the time when the first motor has started being driven, start driving the second motor to open the second door.