High-Frequency Heat Pump Inverter Control for IPM Compressor Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heat pump compressor heating methods using open-phase current and switching element control fail to achieve uniform heating and are limited by noise and efficiency, particularly in systems with permanent magnet synchronous motors where rotor position affects winding inductance.
Innovation Solution
A heat pump device with an inverter control unit that generates high-frequency AC voltage by synchronously switching phases and adding a phase shift component, ensuring efficient heating of refrigerant regardless of rotor position while minimizing noise and motor vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If open-phase current is caused to flow to heat the compressor, then the current does not flow to all the windings, but the compressor cannot be heated uniformly
Solution Approach 1:
Instead of using open-phase current (which excludes one phase), the invention applies three-phase current that flows to all windings simultaneously, ensuring uniform heating across the entire motor structure
Solution Approach 2:
The invention changes the current frequency parameter to high frequency (hf), which enables efficient heating while maintaining uniform current distribution across all phases through proper inverter control
2Adaptability or versatility
If open-phase current is caused to flow to a permanent magnet synchronous motor, then the winding inductance depends on rotor position, but the current may flow to all the phases according to the rotor position, making it difficult to cause the open-phase current to flow
Solution Approach 1:
Instead of attempting to create open-phase current in an IPM motor where all phases conduct, the invention inverts the approach by applying three-phase current to all windings, ensuring heating effectiveness regardless of rotor position and eliminating the need for complex rotor position-based control
Solution Approach 2:
The three-phase current application method works universally for all rotor positions in IPM motors, providing consistent heating effectiveness without requiring position-specific control strategies
3Temperature
If switching elements are repeatedly turned on and off to generate heat, then heat generation by ohmic loss and hysteresis loss is achieved, but the frequency of the current cannot be high frequency, limiting iron loss generation and efficiency improvement
Solution Approach 1:
The invention changes the current frequency parameter to high frequency, which enables rapid heating through increased iron loss generation while maintaining controlled current application through inverter-based PWM switching
Solution Approach 2:
The invention uses periodic PWM switching of inverter elements to generate high-frequency AC current, creating rapid thermal effects through repeated on-off cycles at high frequency while maintaining average current control
4Temperature
If switching elements are repeatedly turned on and off to generate heat, then heating is achieved, but noise may be generated
Solution Approach 1:
The invention changes the current frequency to high frequency, which shifts the noise spectrum beyond audible ranges and reduces perceptible noise while maintaining effective heating through increased iron loss
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 efficient heating of refrigerant in compressors with IPM motors, reducing noise and motor shaft vibrations, and improving heating uniformity and efficiency by generating high-frequency AC voltage based on phase switching and phase addition, thus preventing liquid compression and extending compressor lifespan.
Implementation Method 1
a voltage generation unit that generates a voltage command value based on the phase θ3 output by the addition unit
Implementation Method 2
heat generation by an hysteresis loss is performed so that sufficient preheating can be performed
Implementation Method 3
heat generation by an ohmic loss
Data Source
AI summary
An adder adds a phase θplus, which is n times a size of 60 degrees, to a phase output from a phase switching unit and outputs the phase as a voltage command phase θ. A voltage generation unit generates voltage command value based on the voltage command phase output by the adder and outputs the command value. A drive-signal generation unit, based on an output from the voltage generation unit generates drive signals corresponding to respective switching elements of an inverter, and outputs respective generated drive signals to the corresponding switching elements of the inverter, and generates a high-frequency AC voltage in the inverter.