Domestic refrigeration appliance with a coolant circuit and method for operating a domestic refrigeration appliance with a coolant circuit
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Solution Overview
Problem
Existing domestic refrigeration appliances face challenges in efficiently and quietly stopping the compressor, leading to potential noise and energy inefficiencies during shutdown.
Innovation Solution
A method and apparatus utilizing a three-phase motor with a controlled actuator to gradually reduce the compressor's rotational speed to a minimum and then de-energize the motor windings, allowing the compressor to reach a full shutdown, with optional active braking to prevent backward rotation, ensuring quiet operation and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the compressor is switched off immediately by de-energizing the motor windings, then the shutdown process is quick and simple, but the compressor generates noise and energy inefficiency during stopping
Solution Approach 1:
The patent applies preliminary action by gradually reducing the rotational speed of the three-phase motor to a predetermined minimum rotational speed before de-energizing the motor windings. This preliminary speed reduction phase prepares the compressor for shutdown in a controlled manner, preventing sudden stops that generate noise and energy inefficiency. The actuator actively controls the motor to decelerate smoothly, ensuring quiet operation during the transition to complete shutdown.
2Loss of energy
If the rotational speed is reduced gradually to a minimum before shutdown, then noise and energy efficiency improve, but the shutdown process takes longer
Solution Approach 1:
The patent applies preliminary action by gradually reducing the rotational speed of the three-phase motor to a predetermined minimum rotational speed before de-energizing the motor windings. This preliminary speed reduction phase prepares the compressor for shutdown in a controlled manner, preventing sudden stops that generate noise and energy inefficiency. The actuator actively controls the motor to decelerate smoothly, ensuring quiet operation during the transition to complete shutdown.
Solution Approach 2:
The shutdown process is divided into distinct periodic phases: first, the actuator gradually reduces the motor rotational speed to a predetermined minimum speed over a controlled time period; second, the motor windings are de-energized for a predetermined period to allow the rotor to come to complete rest. This periodic structuring of the shutdown process optimizes both energy efficiency and noise reduction while managing the total shutdown time.
3Reliability
If the three-phase motor is de-energized immediately, then the shutdown is fast, but the compressor may experience backward rotation and operational instability
Solution Approach 1:
The patent applies preliminary action by gradually reducing the rotational speed of the three-phase motor to a predetermined minimum rotational speed before de-energizing the motor windings. This preliminary speed reduction phase prepares the compressor for shutdown in a controlled manner, preventing sudden stops that generate noise and energy inefficiency. The actuator actively controls the motor to decelerate smoothly, ensuring quiet operation during the transition to complete shutdown.
Solution Approach 2:
The shutdown process is divided into distinct periodic phases: first, the actuator gradually reduces the motor rotational speed to a predetermined minimum speed over a controlled time period; second, the motor windings are de-energized for a predetermined period to allow the rotor to come to complete rest. This periodic structuring of the shutdown process optimizes both energy efficiency and noise reduction while managing the total shutdown time.
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
The solution enables a quieter and more energy-efficient compressor shutdown, ensuring the compressor reaches zero rotational speed effectively, reducing noise and energy consumption.
Implementation Method 1
a three-phase motor, which has motor windings to which electric power can be applied for operation of the three-phase motor
Implementation Method 2
a compressor, which comprises a three-phase motor... a coolant circuit which is provided for cooling the coolable interior
Data Source
AI summary
A domestic refrigeration appliance has a heat-insulated housing with a coolable inner container delimiting a coolable interior for storing foods. The interior is cooled with a coolant circuit that includes a compressor with a three-phase motor operated by an actuator via electrically powered motor windings. The actuator is actuated at least indirectly to operate the compressor in a switched-on state with a rotational speed of the three-phase motor at least approximately equal to a predetermined rotational speed. The actuator is caused to switch off the compressor such that the rotational speed of the three-phase motor decreases to a predetermined minimum rotational speed, and thereafter to switch off the three-phase motor for at least a predetermined period of time by de-energizing the motor windings. The period of time is selected long enough to reduce the speed of the motor, beginning from the minimum rotational speed, to reach standstill.