Brushless Motor Waveform Switching for Output and Noise Balance
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Solution Overview
Problem
Existing wiper devices for vehicles face challenges in flexible motor control that balance current consumption and motor output, particularly in high-speed operations, leading to increased noise and inefficiency.
Innovation Solution
A motor control device that switches between a sine wave drive in low-output mode and a wide-angle trapezoidal wave drive in high-output mode, using a brushless motor with a rotor and three-phase armature coils, adjusting current-supply signals based on rotor position to optimize efficiency and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rectangular wave drive is used in high-speed working mode, then motor output is improved, but magnetic sound and noise increase
Solution Approach 1:
The patent applies dynamics by making the drive waveform adjustable between rectangular wave and sine wave based on operational requirements. The control system dynamically switches between drive modes: rectangular wave for high-speed/high-output modes and sine wave for low-speed/quiet modes, optimizing both performance and noise characteristics across different operating conditions
Solution Approach 2:
The patent changes the drive waveform parameter from fixed rectangular wave to variable waveform (rectangular or sine) based on speed and output requirements. By adjusting the waveform shape and current supply angle parameters, the system achieves high motor output when needed while suppressing magnetic sound during normal operation
2Power
If an advance-angle/wide-angle current-supply drive is used, then motor output is improved, but current consumption increases
Solution Approach 1:
The control system dynamically adjusts the current supply angle and waveform based on the required motor output. During high-output demands, advance-angle/wide-angle drive is applied; during normal operation, rectangular or sine wave drive with smaller current angles is used, thereby optimizing the balance between motor output and current consumption
3Object-generated harmful factors
If a sine wave drive is used in low-speed working mode, then working sound is reduced, but motor output is limited
Solution Approach 1:
The system dynamically switches between sine wave drive for low-speed/quiet operation and rectangular wave or advance-angle drive for high-speed/high-output operation. This dynamic waveform selection allows the motor to operate quietly during normal conditions while delivering high output when required
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 allows for flexible motor control that reduces current consumption and suppresses noise in high-speed operations, enhancing the motor's output characteristics and efficiency.
Implementation Method 1
a brushless motor including a rotor and a three-phase armature coil of U-phase, V-phase, and W-phase
Data Source
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AI summary
A motor control device for controlling a brushless motor comprising a rotor and a three-phase armature coil, said motor control device comprising: a position detection unit which detects the rotational position of the rotor; a control unit (54), which, in a first or second control mode, outputs a first or second drive signal to an inverter (52) at a current-supply time based on the rotational position of the rotor; and the inverter (52) which outputs a first or second current-supply signal to the three-phase armature coil when the first or second drive signal is input, wherein for any two of the three phases, a duty value when the duty of the applied voltages is the same is larger in the second control mode than in the first control mode.