Brushless Motor Dynamic Energization Pattern Switching
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Solution Overview
Problem
The freeless driving/energization method for brushless motors degrades motor properties, leading to potential failure in wiper devices during high load states, as it cannot maintain effective wiping performance.
Innovation Solution
A brushless motor system that dynamically switches between freeless and rectangular wave energization patterns based on accumulated load values, using a controller to adjust the energization patterns to ensure optimal performance by switching to rectangular wave energization when loads exceed a threshold and reverting to freeless when loads are low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If freeless driving/energization method is used, then motor operation noise is reduced, but motor properties are degraded
Solution Approach 1:
The patent applies dynamics by making the energization pattern adjustable and switchable between different modes (freeless driving and rectangular wave driving) based on operational conditions. The control unit dynamically selects the appropriate energization pattern according to the accumulation value, allowing the motor to adapt its characteristics to different load conditions and maintain both low noise and reliable performance as needed.
2Object-generated harmful factors
If freeless driving/energization method is used, then motor operation noise is reduced, but wiping performance fails in high load state
Solution Approach 1:
The system dynamically switches between freeless driving and rectangular wave driving based on the accumulation value that reflects load conditions. When the accumulation value is below the threshold, freeless driving provides low noise operation. When the accumulation value exceeds the threshold (indicating high load), the system switches to rectangular wave driving to ensure sufficient wiping performance, thus dynamically adapting to maintain both noise reduction and productivity.
Solution Approach 2:
The patent changes the energization pattern parameter based on operational conditions. By monitoring the accumulation value and switching between different energization patterns (freeless vs. rectangular wave), the system adjusts the electrical parameters supplied to the motor to optimize both noise reduction and wiping performance according to the current load state.
3Reliability
If rectangular wave energization is used, then motor properties are improved, but motor operation noise increases
Solution Approach 1:
The system uses dynamic switching between energization patterns based on the accumulation value. Rectangular wave energization is applied only when the accumulation value exceeds the threshold, indicating high load conditions where motor properties and wiping performance are critical. During normal low-load operation, the system uses freeless driving to minimize noise, thus dynamically balancing performance and noise considerations.
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 solution enables wiper devices to maintain effective wiping performance during high load states by improving motor properties through dynamic energization pattern switching, reducing motor operation noise and ensuring reliable operation.
Implementation Method 1
an inverter including a plurality of switching elements, the inverter being configured to conduct an alternating current to the three-phase windings by turning on or off the plurality of switching elements
Implementation Method 2
a rotor including a permanent magnet, the rotor being configured to rotate in a state facing the stator
Data Source
Figure 1~2
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Figure 5~6
AI summary
A brushless motor includes a stator including three-phase windings, a rotor that includes a permanent magnet and rotates in a state facing the stator, an inverter that includes a plurality of switching elements and conducts an alternating current to the three-phase windings by turning on or off the plurality of switching elements, and a controller that controls on or off states of the plurality of switching elements by switching an energization pattern, which represents changes in energization states of phases of the three-phase windings according to rotation of the rotor, to a freeless energization pattern or a rectangular wave energization pattern, wherein the controller switches the energization pattern to the freeless energization pattern when an accumulated load value determined according to a load on the rotor is less than a first predetermined threshold value and switch the energization pattern to the rectangular wave energization pattern when the accumulated load value is equal to or greater than the first predetermined threshold value.