Duct Air Conditioner Fan Coordination Under Motor Current Limiting
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Solution Overview
Problem
Existing duct-type air conditioning apparatuses face challenges in achieving a desired air amount due to insufficient airflow when a high-output motor and driver circuit are required, leading to increased complexity and cost, and the current limiting function disrupts the performance balance between main and auxiliary motors.
Innovation Solution
The air conditioning apparatus incorporates multiple blowing parts with separate fans and motors, where one motor operates with a current limiting function, and the controlling part adjusts the rotational speed of the other motor to maintain a desired airflow by transmitting different rotational speed commands, allowing for appropriate airflow adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-output motor and driver circuit are added to increase air amount, then the air amount is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple motors by having them cooperate to drive a single fan. The main motor and auxiliary motor work together to provide the required airflow, eliminating the need for a single high-output motor and its associated complex driver circuit. This combining approach achieves the desired air amount while reducing overall system complexity and cost.
2Productivity
If a driver built-in motor is added as auxiliary motor, then the air amount is improved, but the rotational speed control becomes problematic due to current limiting function
Solution Approach 1:
The controlling part monitors the operation state of the main motor and uses this feedback to adjust the rotational speed command for the auxiliary motor. When the main motor operates with current limiting, the controlling part detects this state and相应地 adjusts the auxiliary motor's speed to maintain proper coordination and achieve the desired total airflow.
Solution Approach 2:
The system dynamically adjusts the rotational speed of the auxiliary motor based on the operating conditions of the main motor. The speed command for the auxiliary motor is not fixed but varies according to whether the main motor is operating in current-limited mode or normal mode, enabling adaptive coordination between the two motors.
3Use of energy by moving object
If the main motor operates with current limiting function, then the current is controlled, but the air amount balance between main and auxiliary motors is disrupted
Solution Approach 1:
The controlling part uses feedback from the main motor's current limiting operation to dynamically adjust the auxiliary motor's rotational speed. This feedback mechanism ensures that when the main motor's current is limited, the auxiliary motor compensates by adjusting its contribution, thereby maintaining the proper air amount balance between the two motors.
Data Source
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AI summary
Provided is an air conditioning apparatus that appropriately adjusts, in accordance with adjustment of a rotational speed of one motor, a rotational speed of the other motor. Provided is a duct-type air conditioning apparatus 1 in which a first blowing part 12 has a current limiting function for rotating a first fan 20 at a rotational speed lower than a first rotational speed instructed by a first rotational speed command V1 to let current driving the DC motor 21 be equal to or lower than a predetermined limit value, and when the first blowing part 12 operates with the current limiting function, a controller 15 transmits a limit rotational speed command V3 different from a second rotational speed command V2 to a second blowing part 18 and controls a second fan 23 so as to rotate at a third rotational speed lower than a second rotational speed.