Heat pump device, air conditioner, and cooling machine
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Solution Overview
Problem
Existing heat pump devices face inefficiencies in heating the compressor, leading to inadequate heat generation, increased vibration, and noise due to high-frequency single-phase alternating-current power supply and reduced winding resistance in modern motors, which affects reliability and heat dissipation costs.
Innovation Solution
A heat pump device with a three-phase motor and inverter control unit that switches between normal and heating operation modes, using high-frequency energization to heat the compressor without rotation, and employing a step-down converter to manage bus voltage, ensuring efficient heat generation and reduced noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-frequency single-phase alternating-current power supply is used to heat the compressor, then the compressor can be heated without rotation, but the heating efficiency degrades due to fast current decay during off-period and insufficient heat generation with low iron loss motors
Solution Approach 1:
The patent changes the power supply parameters from single-phase to three-phase high-frequency power supply. This parameter change eliminates the fully-off period problem inherent in single-phase systems, allowing continuous high-frequency current flow through the motor windings. The three-phase system maintains steady-state oscillating current that continuously generates heat in the compressor without the efficiency losses associated with single-phase systems.
Solution Approach 2:
The patent uses the motor windings themselves as the heating element by applying high-frequency three-phase power. Instead of using a separate heating system, the existing motor structure is utilized for both its original function and as a heating source, copying the electrical pathway to serve dual purposes.
2Temperature
If direct current is caused to flow in the motor winding for preheating, then the rotor does not rotate, but the electric current increases due to reduced winding resistance, causing increased inverter loss and heat dissipation problems
Solution Approach 1:
The patent changes the current type from direct current to high-frequency alternating current. This parameter change allows the system to take advantage of the motor's inductance to limit current flow during the off-periods of the PWM cycle, reducing the overall current magnitude required for heating while maintaining effective heat generation. The alternating nature of the current prevents the continuous high current draw that occurs with DC preheating.
3Object-affected harmful factors
If high-frequency single-phase alternating-current power supply is used, then noise is reduced by being outside audible range, but vibration increases due to resonance frequency and the fully-off period causes inefficient current flow
Solution Approach 1:
The patent changes the power supply configuration from single-phase to three-phase high-frequency power. This parameter change eliminates the fully-off period that causes resonance vibrations in single-phase systems. The three-phase system maintains continuous electromagnetic force application to the rotor, preventing the periodic startup-stop vibrations that occur with single-phase operation. The high frequency keeps noise outside the audible range while the three-phase configuration eliminates resonant vibration.
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 stable and efficient heating of refrigerant on standby, reduces compressor vibration and noise, and improves reliability by optimizing heat generation and inverter efficiency, aligning with stringent environmental standards.
Implementation Method 1
a high-frequency voltage is applied to a motor 8 to heat a compressor 1 without rotationally driving the motor 8
Implementation Method 2
the amount of heat generation is given by the product of the winding resistance and the square of the electric current
Implementation Method 3
a technology of stepping down, with a converter unit, an input voltage to an inverter
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heat pump device includes a compressor 1 including a compression mechanism 7 that compresses a refrigerant and a motor 8 that drives the compression mechanism 1, an inverter 9 that applies a voltage for driving the motor 8, a converter 10 that applies a voltage to the inverter 9, an inverter control unit 12 that generates a driving signal for driving the inverter 9, and a converter control unit 17 that generates a driving signal for driving the converter 10, wherein the inverter control unit 12 includes a heating operation mode in which a heating operation of the compressor 1 is performed and a normal operation mode in which a refrigerant is compressed by performing a normal operation of the compressor 1 and the converter control unit 17 sets, in the heating operation mode of the inverter control unit 12, a voltage applied to the inverter 9 on the basis of a voltage command value for the motor 8.