Brushless Motor Braking with Variable Phase Delay Control
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Solution Overview
Problem
Brushless motors used in devices with rotary members, such as grass mowers and roller conveyors, face issues with inertia during stoppage, leading to loose fasteners and potential hazards or damage, as existing technologies do not effectively manage the motor's stoppage to minimize inertia.
Innovation Solution
A brake-controllable brushless motor system with a rotor, stator, and a controller that uses polyphase coils, a polar position detector, and a delayed pulse generator to progressively and continuously enlarge the phasic delay of pulse signals, ensuring controlled electric supply to the coils during braking, thereby gradually stopping the motor and reducing inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor is stopped suddenly, then the stopping time is short and productivity is improved, but the inertia causes loose fasteners and safety hazards
Solution Approach 1:
The patent applies dynamic braking control by continuously varying the phase delay of the braking pulses based on the motor's instantaneous speed. The delay time is dynamically adjusted to be proportional to the rotational speed, creating a braking force that adapts to the changing motion state. This dynamic approach allows the motor to stop quickly while maintaining controlled deceleration that prevents inertia-related fastener loosening.
Solution Approach 2:
The patent changes the timing parameter of the braking signal by introducing a variable phase delay. The delay time is modified based on the detected rotational speed, transforming the braking control from a fixed-time approach to a speed-dependent approach. This parameter change enables the braking force to be optimized at each moment, achieving both short stopping time and reliable fastener retention.
2Reliability
If the motor is stopped gradually, then the inertia is minimized and safety is improved, but the stopping time increases and productivity decreases
Solution Approach 1:
The system uses dynamic pulse generation where the braking signal's phase delay is continuously adjusted according to the motor's real-time speed. This creates a braking profile that is gentle at high speeds (ensuring safety) but becomes more aggressive as speed decreases (reducing total stopping time). The dynamic adaptation allows the motor to follow an optimal deceleration curve that balances safety and productivity.
Solution Approach 2:
The patent employs periodic pulse signals with varying phase delays to control the braking process. By modulating the timing of these periodic pulses based on speed feedback, the system creates a rhythmic braking action that efficiently dissipates kinetic energy while maintaining controlled deceleration. This periodic control with variable timing achieves both safety and efficiency.
3Device complexity
If conventional braking is used, then the structure is simple, but the inertia causes falling objects and damage in roller conveyors
Solution Approach 1:
The patent implements a feedback mechanism where the motor's rotational speed is continuously detected and used to adjust the braking pulse timing. The speed information feeds back to the pulse generator, which modifies the phase delay accordingly. This closed-loop feedback ensures that the braking force is always appropriate for the current speed, preventing sudden stops that would cause objects to fall or damage in roller conveyor applications.
Solution Approach 2:
The patent introduces an intermediary control element (the variable phase delay mechanism) between the braking signal generation and the motor. This intermediary processes the speed information and translates it into appropriate timing adjustments, acting as a mediator that smooths out the braking action. This intermediary control prevents direct, harsh braking that would cause object damage while maintaining relatively simple overall system structure.
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 solution effectively minimizes inertia during motor stoppage, preventing loose fasteners and damage, ensuring safer operation and reducing the risk of accidents or content damage in devices with rotary members.
Implementation Method 1
a polar position detector whereby electric power is supplied to the coil selected by its phase in response to the polar position of the rotor detected by the polar position detector
Implementation Method 2
a delayed pulse generator for producing phase-delayed pulse signals in response to the pulse signals fed from the motor pulse identifier 30
Implementation Method 3
a rotor and a stator having polyphase coils
Implementation Method 4
a chargeable battery for storing the electric power induced when the brushless motor is stopped
Data Source
AI summary
A brake-controllable brushless motor has a rotor and a stator having polyphase coils; a polar position detector whereby electric power is supplied to the coil selected by its phase in response to the polar positions of the rotor detected by the polar position detector; a driver division for controlling the electric supply to the coils; a motor pulse identifier for recognizing motor pulse signals fed from the polar position detector; and a delayed pulse generator for producing phase-delayed pulse signals in response to the pulse signals fed from the motor pulse identifier, thereby ensuring that when the brushless motor is braked, the phase delay of the delayed pulse signals is progressively and continuously enlarged, and that the coils receive a controlled electric supply from the driver division in response to the delayed pulse signals.