Air conditioner and compressor protection circuit thereof
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Solution Overview
Problem
Existing compressor protection circuits in air conditioners are ineffective in protecting the compressor from damage due to strong interference signals on the drive signal line between the signal processing circuit and the intelligent power module during overcurrent protection processes.
Innovation Solution
A compressor protection circuit incorporating a current sampling module, reference voltage generating module, voltage comparison module, intelligent power module, and signal latching module, which samples phase current, compares it with a reference voltage, and uses a signal latching mechanism to ensure the intelligent power module shuts off the phase current when overcurrent is detected, preventing damage from interference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intelligent power module shuts off the output during overcurrent protection, then the compressor is protected from overcurrent damage, but the drive signal line remains vulnerable to strong interference signals that can still cause large current output or damage
Solution Approach 1:
The patent applies preliminary action by setting the intelligent power module to shutdown state in advance before overcurrent actually occurs. The signal latching module latches the shutdown signal and maintains it even when the drive signal line receives strong interference signals, ensuring the compressor is protected before harmful currents can develop.
Solution Approach 2:
The signal latching module acts as an intermediary between the voltage comparison module and the intelligent power module. It receives the shutdown signal, latches it, and outputs a stable latched shutdown signal that prevents interference signals from directly affecting the intelligent power module's current output control.
2Reliability
If a signal latching module is added to maintain control during shutdown, then protection against interference signals is improved, but the device complexity increases
Solution Approach 1:
The signal latching module is introduced as an intermediary component that provides essential protection functionality. Despite the increase in component count, the module integrates multiple functions (signal latching, shutdown maintenance, interference immunity) into a single unit, minimizing the overall circuit complexity increase while significantly improving reliability.
Data Source
AI summary
An air conditioner and a compressor protection circuit thereof are provided. When overcurrent occurs in a phase current of a compressor, an overcurrent level signal is output by a voltage comparison module, and is latched and output to an intelligent power module by a signal latching module, and the intelligent power module shuts off the output of the phase current according to the overcurrent level signal, so as to achieve the overcurrent protection of the compressor; and subsequently, a conventional level signal is output to the signal latching module by the voltage comparison module, the signal latching module keeps outputting the overcurrent level signal, and outputs the conventional level signal until a latching cancel signal output by a signal processing circuit is received, so that the intelligent power module starts the output of the phase current, thereby enabling the compressor to normally operate.