Heat Pump Inverter Current Detection for Constant Compressor Heating
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Solution Overview
Problem
Existing methods for heating compressors in heat pump devices using high-frequency AC voltage face challenges in accurately measuring current flow and controlling heating amounts due to production tolerance and environmental variations.
Innovation Solution
A heat pump device with an inverter and inverter control unit that detects current values during de-energized sections of high-frequency AC voltage application, allowing for precise control of the peak current and maintaining constant heating by adjusting the high-frequency AC voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-frequency AC voltage is supplied to the compressor to heat the compressor, then the heating effect is improved, but the current measurement accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting the current value during the de-energized section (zero voltage period) before the high-frequency voltage is fully applied to the compressor. This timing allows the current measurement to be taken when the voltage influence is minimal, enabling accurate current detection that can then be used to control the heating amount without being affected by the high-frequency voltage interference
Solution Approach 2:
The patent uses the de-energized section (zero voltage period) as an intermediary measurement window. This intermediate period between voltage applications serves as a mediator that allows current detection without the interfering high-frequency voltage, bridging the gap between heating requirements and measurement accuracy
2Temperature
If high-frequency AC voltage is supplied to the compressor, then the heating effect is improved, but the control precision deteriorates due to production tolerance and environment variations
Solution Approach 1:
The patent implements feedback control by detecting the actual current value during the de-energized section and using this detected current value to adjust and control the high-frequency voltage generation. This closed-loop feedback mechanism compensates for production tolerances and environmental variations, maintaining precise heating control despite these disturbances
Solution Approach 2:
The patent replaces open-loop mechanical control with electronic feedback control. Instead of relying on fixed mechanical parameters that are susceptible to tolerance variations, the system uses electronic current detection and adaptive voltage control to achieve precise heating management that compensates for manufacturing and environmental variations
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 ensures consistent heating of the compressor, regardless of production tolerance and environmental variations, by accurately detecting and controlling the current flow, thereby optimizing heating efficiency.
Implementation Method 1
a high-frequency-voltage generation unit that causes the inverter to generate a high-frequency AC voltage according to a current value detected by the current-value detection unit
Implementation Method 2
an inverter that applies a predetermined voltage to the motor; and an inverter control unit that causes the inverter to generate a high-frequency AC voltage
Data Source
AI summary
An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.