Brushless Motor Torque Ripple Reduction via Sensor Signal Correction
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Solution Overview
Problem
Conventional electric motors, both brushed and brushless, experience increased torque ripples at the rotor due to control conditions, and existing brushless motor systems do not effectively utilize sensor signals for optimal rotor phase detection.
Innovation Solution
A brushless motor system with a mode switching unit for low-speed and high-speed modes, utilizing a signal correcting unit to adjust sensor output signals and an element control unit for selective energization control, including first, second, and third energization controls, to optimize rotor torque and reduce torque ripples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional brushless motor control is used with standard sensor signal utilization, then the control system is simple, but torque ripples at the rotor increase
Solution Approach 1:
The patent applies feedback by detecting the actual rotor phase using sensors and correcting the sensor output signals based on the relationship between detected phases and ideal phases. The control unit uses this corrected information to adjust energization timing, creating a closed-loop control system that reduces torque ripples while maintaining controlled complexity.
Solution Approach 2:
The patent changes the parameter of energization timing by correcting sensor output signals to advance or delay coil energization relative to standard timing. This parameter adjustment optimizes the magnetic field interaction with the rotor, reducing torque ripples without requiring fundamental changes to the control system architecture.
2Device complexity
If sensor output signals are used without correction, then the control system is simple, but sensor signal utilization is ineffective
Solution Approach 1:
The control unit implements feedback by comparing detected rotor phases with ideal phases and using this information to correct sensor output signals. This feedback mechanism transforms raw sensor data into precise control information, effectively utilizing sensor signals while maintaining reasonable processing complexity.
Solution Approach 2:
The patent replaces direct mechanical phase detection with electronic signal correction. Instead of relying on perfectly positioned mechanical sensors, the system uses electronic processing to correct sensor signals, substituting mechanical precision requirements with electronic computation.
3Device complexity
If standard energization control is used, then the control method is simple, but rotor torque optimization is insufficient
Solution Approach 1:
The patent optimizes rotor torque by changing the timing parameter of coil energization. The control unit corrects sensor signals to determine optimal energization moments, advancing or delaying current application to coils based on actual rotor position feedback, thereby maximizing torque production.
Solution Approach 2:
The system performs preliminary action by correcting sensor signals in advance of the actual energization event. This allows the control unit to prepare the optimal energization timing before the rotor reaches the critical position, ensuring maximum torque efficiency.
4Device complexity
If conventional wiper control with fixed speeds is used, then the control system is simple, but noise generation cannot be optimized
Solution Approach 1:
The patent applies dynamics by enabling the wiper to operate in multiple speed modes (low-speed and high-speed) rather than a fixed speed. The control unit dynamically selects the appropriate mode based on operational conditions, optimizing noise reduction during low-speed operation while maintaining efficiency during high-speed operation.
Solution Approach 2:
The system changes the speed parameter of the wiper motor based on operational requirements. By correcting sensor signals and adjusting energization timing, the control unit optimizes the motor's operating characteristics for different speed modes, reducing noise generation particularly during low-speed operation.
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 effectively suppresses torque ripples and improves sensor signal utilization, allowing for precise control of rotor rotation phases and reduced noise generation.
Implementation Method 1
currents are supplied to the three coils at predetermined timing, and a rotating magnetic field is formed by the three coils to rotate the rotor
Implementation Method 2
based on the intensity of the magnetic field formed by the sensor magnet, three sensors which output signals are provided to correspond to the U-phase, the V-phase, and the W-phase
Data Source
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AI summary
A brushless motor (18) which supplies currents to coils (U1, U2, V1, V2, W1, and W2) and rotates a rotor (27), the brushless motor comprising a control apparatus (37) which switches and selectively executes: first energization control to start energization to the coils (U1, U2, V1, V2, W1, and W2)at first timing, and to continue the energization for a first period to control the rotation number of the rotor (27); and second energization control to start energization to the coils (U1, U2, V1, V2, W1, and W2) at second timing advanced by an electric angle with respect to the first timing, and to continue the energization for a second period longer than the first period to control the rotation number of the rotor (27).