Compressor Motor Heating With High-Frequency AC to Cut Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air-conditioning compressor heating methods using open-phase currents face challenges in uniform heating due to rotor-position-dependent winding inductance and limited frequency, leading to inefficiencies and noise issues, while also failing to meet stringent environmental standards for energy efficiency and noise reduction.
Innovation Solution
The method involves generating a high-frequency AC voltage out of the operating frequency range for the compressor's motor coils using a PWM signal, which heats the refrigerant through iron and copper losses, reducing mechanical vibrations and noise, and optimizing the frequency to exceed 14 kHz for reduced audible noise and increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If open-phase current is used to heat the compressor, then the compressor can be warmed up, but uniform heating cannot be achieved and coils may not receive current
Solution Approach 1:
The patent changes the electrical parameters by applying three-phase AC voltage at a frequency higher than the operating frequency (e.g., 1.5-2 times the operating frequency). This frequency parameter change ensures that current flows through all three phases simultaneously regardless of rotor position, achieving uniform heating of the compressor while avoiding the rotor-position-dependency problem of open-phase current methods.
2Productivity
If high-frequency AC voltage is applied to heat the compressor, then heating efficiency improves, but winding inductance variability may prevent current flow through all phases
Solution Approach 1:
The patent applies AC voltage at a frequency that is excessively high compared to the operating frequency (1.5-2 times or higher). This excessive frequency application ensures that the inductive reactance is sufficiently high to limit current magnitude but low enough to allow current flow through all phases, overcoming the rotor-position-dependency issue while maintaining heating efficiency.
3Manufacturing precision
If low-frequency current is used for heating, then uniform heating can be achieved, but iron loss is limited and efficiency improvement is hindered
Solution Approach 1:
The patent changes the frequency parameter to a value higher than the operating frequency, which increases iron loss and thereby improves heating efficiency. The three-phase AC voltage application ensures that this high-frequency current flows through all phases simultaneously, achieving both uniform heating and improved energy efficiency by utilizing the iron loss at elevated frequencies.
4Temperature
If conventional heating current is applied, then the compressor can be warmed up, but vibrations and noises of the bearing increase
Solution Approach 1:
The patent changes the frequency parameter to a high frequency (1.5-2 times or more the operating frequency) for the heating current. This high-frequency AC current generates heat through iron and copper losses without producing significant mechanical vibrations or bearing noises, as the high frequency is above the audible range and does not resonate with the mechanical components of the compressor.
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 approach achieves efficient heating of the compressor with reduced vibrations and noise, enhances refrigerant evaporation, and aligns with eco-design standards by minimizing electrical consumption and inverter losses, thereby preventing compressor damage and improving overall performance.
Implementation Method 1
the refrigerant in the compressor is heated by iron loss and copper loss in the motor
Implementation Method 2
the refrigerant in the compressor is heated by iron loss and copper loss in the motor
Implementation Method 3
PWM signal generating means to cause the inverter to generate a high-frequency AC voltage by generating a PWM signal
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In order to be able to comply itself to the environment-conscious design standard, a refrigerant heating method is obtained with high efficiency during standby and reduction of vibrations and noises of a bearing in a compressor. An compressor 1, a motor 8 to drive the compressor 1, an inverter 9 to apply a desired voltage to the motor 8, an inverter control means 11 to control the inverter 9, and a bus voltage detecting means 10 to detect a bus voltage of the inverter 9 are provided, in which the inverter control means 11 includes dormant refrigerant detecting means 12 to detect a dormant state of refrigerant in the compressor 1, high-frequency AC voltage generating means 13 to output a high-frequency AC voltage command out of a range of an operating frequency when the motor 8 is undergoing compression operation to a coil of the motor 8 on the basis of an output of the dormant refrigerant detecting means 12, an amplitude, and a phase, and PWM signal generating means 15 to cause the inverter 9 to generate a high-frequency AC voltage by generating a PWM signal on the basis of the output of the high-frequencyAC voltage generating means 13 and the output of the bus voltage detecting means 10.