Air conditioner
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Solution Overview
Problem
Existing air conditioner systems face issues with controlling the occurrence of failure in connection switching units, which can lead to malfunction and secondary failures, despite being able to switch between Y and Δ connection states for efficient motor driving.
Innovation Solution
An air conditioner system with a connection control unit that restricts switching of connection states when a predetermined count threshold is exceeded, using a connection switching unit to manage the switching of coils between Y and Δ connection states, thereby preventing excessive switching and potential failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If connection switching is performed frequently to maintain high efficiency and output power, then motor efficiency and output power are improved, but the reliability of the connection switching unit deteriorates due to increased failure risk
Solution Approach 1:
The control unit counts the number of switching operations in advance and compares it with a predetermined threshold value before allowing switching. This preliminary action prevents excessive switching that would lead to failure, while still permitting adequate switching to maintain motor efficiency during the safe operation range.
2Reliability
If connection switching is restricted to prevent failure, then the reliability of the connection switching unit is improved, but the motor efficiency and output power deteriorate due to limited switching capability
Solution Approach 1:
The control unit counts the number of switching operations in advance and compares it with a predetermined threshold value before allowing switching. This preliminary action prevents excessive switching that would lead to failure, while still permitting adequate switching to maintain motor efficiency during the safe operation range.
3Reliability
If the switching count threshold is set low to prevent failure, then the connection switching unit reliability is improved, but the ability to maintain high efficiency deteriorates due to restricted switching operations
Solution Approach 1:
The control unit adjusts the switching decision based on the switching count parameter. When the count is below the threshold, switching is permitted to maintain efficiency; when the count exceeds the threshold, switching is restricted to prevent failure. This dynamic parameter adjustment optimizes both reliability and performance.
Data Source
AI summary
An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate DC voltage, an inverter to generate three-phase AC voltage from the DC voltage, a motor to generate driving force to drive the compressor by using a plurality of coils to which the three-phase AC voltage is applied, a connection switching unit to switch connection states of the plurality of coils, and an outdoor control device to control the connection switching unit. The outdoor control device restricts the switching of the connection states when a switching count of the connection states exceeds a count threshold value.