Domestic refrigeration device with a coolant circuit, and method for operating a domestic refrigeration device with a coolant circuit
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Solution Overview
Problem
Household refrigeration appliances with permanently excited three-phase synchronous motors face challenges in achieving improved startup behavior and torque management, particularly in extending the speed range while maintaining efficient operation.
Innovation Solution
A household refrigeration appliance with a field-oriented regulated electric drive using a permanent-magnet three-phase synchronous motor, where a first current control circuit manages the main torque and a second current control circuit adjusts a longitudinal current to generate additional torque, with output signals controlling a converter to enhance starting behavior and torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If field-oriented control with a permanently excited three-phase synchronous motor is used to drive the compressor, then the speed range can be extended and operation can be maintained, but the startup behavior and torque management are insufficient
Solution Approach 1:
The patent applies preliminary action by pre-setting the longitudinal current component (id) to a non-zero value before and during the startup phase. This preliminary current injection prepares the motor to generate sufficient starting torque, resolving the contradiction between maintaining extended speed range operation and achieving reliable startup behavior. The control method adjusts the longitudinal current dynamically, starting with a non-zero value for startup and then transitioning to zero for normal operation.
2Device complexity
If the longitudinal current setpoint is set to zero for field-oriented control, then the control is simplified, but the total torque is reduced and cannot meet startup requirements
Solution Approach 1:
The patent applies dynamics by making the longitudinal current setpoint (id) a dynamic variable rather than a static zero value. The control method dynamically adjusts id based on the operational phase: during startup, id is set to a non-zero value to maximize torque generation, and after successful startup, id transitions to zero for efficient normal operation. This dynamic adjustment resolves the contradiction between control simplicity and torque sufficiency.
3Reliability
If a non-zero longitudinal current is used during startup to increase total torque, then startup behavior is improved, but computing power requirements increase for complex calculations
Solution Approach 1:
The patent applies parameter changes by modifying the longitudinal current setpoint (id) from its conventional zero value to a phase-dependent value. During startup, id is changed to a non-zero value to enhance torque, and after startup, it returns to zero. This parameter adjustment is implemented through a straightforward control logic that avoids complex real-time calculations, thus resolving the contradiction between improved startup behavior and reduced computing 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
The solution improves the starting behavior and overall torque of the compressor by increasing the total torque beyond the main torque, allowing for efficient operation and extended speed range without complex calculations, thus reducing computing power requirements.
Implementation Method 1
a permanent-magnet three-phase synchronous motor, where a first current control circuit manages the main torque
Implementation Method 2
In field-oriented control, also known as vector control, the electrical voltages and currents of the three-phase synchronous motor are combined in the form of space vectors
Implementation Method 3
the permanent magnet three-phase synchronous motor generates an additional torque to the main torque due to the resulting longitudinal current
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a domestic refrigeration device (1) and to a method for operating a domestic refrigeration device (1). The domestic refrigeration device (1) comprises a heat-insulated body (10) with a coolable inner container (2) which delimits a coolable interior (3) provided for storing food; a coolant circuit (20) which is provided for cooling the coolable interior (3) and which comprises a compressor (21); and a field-oriented electric drive (30). The field-oriented electric drive (30) comprises a field-oriented controller (34), a converter (32), and a permanently excited synchronous motor (31) which is connected downstream of the converter (32) and which is part of the compressor (21) or is provided for driving the compressor (21).