Brushless DC Motor Door Operator Energy Recovery
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Solution Overview
Problem
Existing door operators face inefficiencies in energy recovery and storage due to mechanical and electrical inefficiencies, limited energy capture from spring systems, and reliance on low-cost but inefficient brushed DC motors, which lead to premature failure and unsafe door operation.
Innovation Solution
A door operator system utilizing a brushless DC motor with a high gear ratio and a one-way roller clutch, combined with a non-volatile door position sensor and advanced control algorithms, to optimize energy capture and storage, and ensure safe and efficient door operation even in power loss scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a brushed DC motor is used to drive the door operator, then the device complexity is reduced and cost is lowered, but the motor cogging and rotor inertia increase leading to premature failure and unsafe door operation
Solution Approach 1:
The patent replaces the brushed DC motor with a brushless DC motor. This substitution eliminates the mechanical brushes and commutator system, thereby reducing mechanical friction and wear while improving reliability and eliminating cogging effects associated with brushed motors.
Solution Approach 2:
The patent changes the motor type from brushed DC to brushless DC, which fundamentally alters the motor's operational parameters including eliminating cogging torque and reducing rotor inertia. This parameter change directly addresses the reliability and safety issues while maintaining acceptable device complexity.
2Force
If a one-way roller clutch with high gear ratio is used, then torque multiplication improves, but the clutch mechanism adds device complexity
Solution Approach 1:
The patent introduces a one-way roller clutch as an intermediary mechanism between the brushless DC motor and the door drive system. This clutch allows the motor to drive the door in both directions while preventing the door from driving the motor during manual operation, thereby enabling torque multiplication without requiring a complex bidirectional motor control system.
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 system significantly improves energy recovery and storage efficiency, reduces motor cogging and rotor inertia, and enhances reliability by using a brushless DC motor and advanced control methods, ensuring safe and efficient door operation with reduced maintenance needs.
Implementation Method 1
a motor to open the door against a spring force
Implementation Method 2
to act as a braking load to control door closing speed when charging the chargeable battery in a generator mode during door closing
Implementation Method 3
a spring force
Data Source
AI summary
A door operator for controlling operation of a door, the door operator having a motor to open the door against a spring force, the door operator further comprising a door position sensor for transmitting a signal indicative of door position; and among other things, calculates a door moment of inertia based on a net torque and the time for the door to reach a predetermined angle from the closed position. Also provided is a door operator that compares door speed to a desired door speed based on a door speed-position profile and generates a door speed error signal and minimizes the door speed error signal by adjusting the braking load resulting from charging a chargeable battery using the motor as a generator.