Air conditioner with switches for allowing an inrush current
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Solution Overview
Problem
Conventional air conditioners require a large and costly additional circuit to prevent inrush current when starting the outdoor unit, leading to increased size and cost.
Innovation Solution
An air conditioner design that includes an indoor unit and outdoor unit connected by power, common, and signal lines, with switches and controllers to manage inrush current flow through the indoor unit's smoother, eliminating the need for a dedicated inrush current prevention circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated inrush current prevention circuit is added to the outdoor unit, then inrush current can be controlled, but the device size and manufacturing cost increase
Solution Approach 1:
The patent merges the inrush current prevention function into the indoor unit's smoother component. The indoor smoother, originally designed for the indoor unit's own inrush current, is utilized to also smooth the inrush current of the outdoor unit by controlling the first switch to connect the outdoor unit's power line to the indoor smoother during startup. This eliminates the need for a separate inrush current prevention circuit in the outdoor unit, reducing device complexity while maintaining reliability
Solution Approach 2:
The indoor smoother is given a dual function: it serves both as the smoother for the indoor unit's power supply and as the inrush current prevention device for the outdoor unit. By enabling the indoor smoother to handle both functions through controlled switching, the patent reduces the total number of components needed in the system, particularly eliminating the outdoor smoother and dedicated inrush current prevention circuit
2Reliability
If a dedicated inrush current prevention circuit is added to the outdoor unit, then inrush current can be controlled, but manufacturing cost increases
Solution Approach 1:
The patent combines the inrush current prevention function with the existing indoor unit components. The indoor smoother and first switch, which are already part of the indoor unit's standard configuration, are utilized to prevent inrush current in the outdoor unit. This merging approach eliminates the need for additional expensive components in the outdoor unit, thereby reducing manufacturing cost while maintaining reliable inrush current control
Solution Approach 2:
The indoor unit provides a service to the outdoor unit by using its own smoother to prevent inrush current. Instead of the outdoor unit needing its own dedicated prevention circuit, it benefits from the indoor unit's smoother capability through controlled connection during startup. This self-service approach reduces the overall system cost by eliminating redundant components
3Reliability
If the outdoor unit uses its own smoother for inrush current, then inrush current is controlled, but the air conditioner size increases
Solution Approach 1:
The patent merges the smoothing function for both indoor and outdoor units into a single component - the indoor smoother. By controlling the first switch to connect the outdoor unit's power line to the indoor smoother during startup, the outdoor unit's inrush current is handled by the indoor smoother rather than requiring a separate outdoor smoother. This consolidation reduces the overall volume of the air conditioner system
Solution Approach 2:
The patent extracts the smoother function from the outdoor unit and relocates it to the indoor unit. The outdoor smoother is eliminated entirely, and its function is taken over by the indoor smoother through controlled switching. This extraction reduces the number of components in the outdoor unit and decreases the overall system size
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 design reduces standby power consumption and manufacturing costs by allowing inrush current to flow through the indoor unit's smoother, thereby downsizing the air conditioner without additional circuitry.
Implementation Method 1
a rectifier connected to a subsequent stage to the second switch to rectify the AC voltage
Implementation Method 2
a smoother to smooth an output of the rectifier
Data Source
AI summary
An air conditioner includes an indoor and outdoor units connected by a power supply line, a common line, and a signal line. The indoor unit includes a first switch for connection between the power supply line and the signal line, and the outdoor unit includes: a second switch for connection between the power supply line and the outdoor unit; a smoother; and a third switch to connect the signal line and a resistor when in an off state, and be open when in an on state, the resister being connected to the second switch. When the outdoor unit starts, the first switch is turned on with the third switch in the off state to allow flow of an inrush current for charging the smoother and, after which, the second switch is turned on and subsequently the first switch is turned off and the third switch is turned on.