Refrigeration Compressor Control with Sensorless Piston Position Detection
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Solution Overview
Problem
Existing domestic refrigeration appliances with refrigerant circuits are not operated efficiently, particularly in terms of compressor performance, due to suboptimal control methods and mechanical characteristics affecting torque and speed regulation.
Innovation Solution
A method and apparatus utilizing a three-phase AC synchronous motor with a field-oriented regulator and inverter control to determine the piston position within the compressor chamber, optimizing compressor operation by analyzing phase currents and angular positions to improve efficiency and reduce noise during startup and shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional compressor control methods are used, then the device complexity is low, but the compressor efficiency and running characteristics are poor
Solution Approach 1:
The patent replaces mechanical position sensing systems with an electrical field-oriented control system that determines piston position through electrical measurements (phase currents) and calculations, eliminating the need for mechanical sensors while improving compressor efficiency and running characteristics
Solution Approach 2:
The system uses the compressor's own electrical parameters (phase currents) to determine piston position and optimize control, making the system self-diagnosing and self-regulating without external sensing components
2Object-affected harmful factors
If conventional motor control is used, then the ease of operation is high, but noise during startup and shutdown is high
Solution Approach 1:
The system determines the piston position before shutdown and uses this information to control the motor to stop at a predetermined position, preventing valve leakage and reducing noise during startup and shutdown operations
Solution Approach 2:
The field-oriented control system continuously monitors electrical parameters and adjusts motor operation based on real-time piston position feedback, optimizing startup and shutdown sequences to minimize noise
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
Enhances compressor efficiency, reduces noise during startup and shutdown, and improves running characteristics by precise control of the three-phase AC synchronous motor, leading to better cooling performance and reduced energy consumption.
Implementation Method 1
a three-phase AC synchronous motor with a number P of pole pairs greater than 1, a stator and a rotor
Implementation Method 2
a control element, which is configured in particular as an inverter, for activating the three-phase AC synchronous motor
Data Source
AI summary
A domestic refrigeration appliance includes an insulated body with a coolable container delimiting a coolable space for food, a refrigerant circuit having a coolant and a compressor for cooling the space, and an electronic control apparatus and an electric drive with a three-phase AC synchronous motor and a control element or inverter for activating the motor. The compressor includes a chamber with an inlet and with an outlet, a piston mounted displaceably within the chamber, a crankshaft and the motor. The motor has a number of pole pairs greater than 1, a stator and a rotor mounted rotatably relative to the stator and coupled to the piston by the crankshaft. During compressor operation, the motor causes the piston to reduce the size of a volume enclosed by the compressor chamber and the piston to compress the coolant. A method for operating a domestic refrigeration appliance is also provided.