Brushless DC Motor Holding Current Reduction
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Solution Overview
Problem
Brushless direct-current motors experience inefficiencies in energy consumption and mechanical stress due to continuous current supply for holding torque, especially when the required holding torque is small, leading to unnecessary energy loss and potential damage from coarse position resolution.
Innovation Solution
A method and device that utilize an iterative holding current reduction technique to minimize the holding current necessary for maintaining the actuating element's position, transitioning from a driving commutation pattern to a holding mode with a reduced current value, eliminating the need for additional sensors and self-locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brushless direct-current motor is supplied with current at full holding torque to compensate for manufacturing tolerances, then the reliability is improved, but the energy consumption increases unnecessarily
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the holding current value based on actual operating conditions. Instead of using a fixed conservative holding current value, the system iteratively reduces the holding current from an initial value until the actuating element remains stationary, thereby optimizing the balance between reliability and energy consumption.
Solution Approach 2:
The system employs self-service through automatic iterative reduction of the holding current value. The control device continuously monitors the position of the actuating element and autonomously adjusts the holding current without external intervention, reducing it step by step until the minimum sufficient value is found, thus eliminating the need for oversized current reserves.
2Loss of energy
If the holding current value is reduced to minimize energy consumption, then the energy efficiency is improved, but the holding torque may become insufficient due to manufacturing tolerances
Solution Approach 1:
The patent implements feedback control by continuously monitoring the position of the actuating element during holding mode. The control device uses position signals to detect whether the actuating element has moved from its target position, and based on this feedback, iteratively adjusts the holding current value to maintain sufficient holding torque while minimizing energy consumption.
Solution Approach 2:
The system applies dynamics by transitioning from a static holding current approach to a dynamic iterative reduction process. The holding current value is not fixed but is continuously adapted based on actual conditions, allowing the system to find the optimal balance between energy efficiency and holding torque sufficiency for each specific operating scenario.
3Stability of the object's composition
If the motor transitions to holding mode after reaching target position, then the position stability is improved, but the continuous current supply causes unnecessary energy loss
Solution Approach 1:
The patent applies partial action by providing only the minimum necessary holding current rather than excessive current. The system iteratively reduces the holding current from an initial conservative value until the actuating element remains stable at its target position, thereby eliminating the excessive energy consumption associated with traditional full holding torque approaches.
Solution Approach 2:
The system uses parameter changes by dynamically adjusting the holding current value based on actual conditions. The holding current is reduced iteratively from an initial value until the actuating element maintains stable position, thereby optimizing the balance between position stability and energy consumption.
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
This approach reduces energy consumption in both the motor and driver to the minimum necessary, preventing unnecessary energy loss and mechanical stress, while ensuring the actuating element is securely held in position without additional reserves for manufacturing tolerances.
Implementation Method 1
The commutation pattern by which the stator windings are energized is determined on the basis of an evaluation of rotor position signals which are provided by Hall-effect sensors and supplied to the electronic circuit.
Data Source
AI summary
During displacement of an actuating element to a target position, a brushless direct-current motor is driven by a driving commutation pattern derived from rotor position signals. After the target position is reached the brushless direct-current motor is transferred to a holding mode in which it is driven by a commutation pattern providing a required holding torque. In the holding mode the holding current necessary for providing the required holding torque is minimized by an iterative holding current reduction method to a holding current value guaranteeing the required holding torque.