Motor-Drive Fallback Control in Air Conditioners
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Solution Overview
Problem
Conventional air conditioners stop operating immediately when communication between the main control unit and the motor-driving control unit becomes abnormal, leading to operational disruptions.
Innovation Solution
An air conditioner design that includes a main control unit, a motor-driving control unit, and an inverter output unit, where the main control unit periodically sends instructions to the motor-driving control unit, and if no new instruction is received within a predetermined time, the motor-driving control unit continues operation based on the last received instruction, ensuring continuous operation even if communication fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air conditioner uses conventional microcomputer control with immediate stop on communication failure, then the control system is simple and reliable for detecting faults, but the operation stops immediately when communication becomes abnormal
Solution Approach 1:
The motor-driving control unit stores the latest motor rotation instruction received from the main control unit in advance. When communication fails, this stored instruction is used to maintain motor operation without immediate shutdown, thus ensuring operation continuity while managing control complexity through proactive data retention
Solution Approach 2:
The system ensures continuous motor operation by having the motor-driving control unit automatically continue executing the last received rotation instruction when new instructions are not received within the expected time frame. This maintains the useful action of motor rotation without interruption despite communication abnormalities
2Reliability
If the air conditioner immediately stops operation when communication fails, then the system responds quickly to faults, but operational disruption occurs
Solution Approach 1:
The motor-driving control unit preliminarily stores the latest rotation instruction and timing information. This preliminary action enables the system to respond accurately to communication failures by comparing expected instruction timing with actual receipt timing, while simultaneously maintaining productivity through continued operation using stored instructions
Solution Approach 2:
The system implements a feedback mechanism where the motor-driving control unit monitors whether new rotation instructions are received within the expected time interval. Based on this feedback, it autonomously decides whether to continue operation using stored instructions or stop, achieving both accurate fault response and operation continuity
Data Source
AI summary
An air conditioner includes a main control unit, and a motor-driving control unit. The main control unit transmits, at every first time, an instruction for rotating the motor to the motor-driving control unit. The motor-driving control unit outputs, on the basis of the instruction, an instruction for rotating the motor to the inverter output unit. When the motor-driving control unit does not receive a new instruction for rotating the motor from the main control unit before the first time elapses from a time when the motor-driving control unit receives the instruction for rotating the motor from the main control unit last, the motor-driving control unit outputs an instruction for continuing operation based on the instruction for rotating the motor received from the main control unit at an immediately preceding time to the inverter output unit.