Motor Drive Controller Phase Synchronization for Noise Reduction
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Solution Overview
Problem
Existing motor drive controllers for non-brush motors with three-phase coils face issues with noise and vibration due to errors in position detection, particularly when Hall ICs are inaccurately mounted, leading to erroneous positional signal changes and frequency variations, which cause sine wave distortion and uneven rotation.
Innovation Solution
A motor drive controller that includes a position detector for initial positional signals, a phase synchronizing circuit to generate high-resolution absolute phase information, and a drive voltage signal outputting device to control periodic current through plural phases, along with a frequency detector and control voltage generator to manage rotation frequency, reducing the impact of arrangement errors and enhancing rotational precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a position detector (Hall IC) is used to detect rotor position, then the motor can be controlled with lower cost compared to high-resolution encoders, but arrangement errors during reflow mounting cause positional signal errors leading to sine wave distortion and increased noise
Solution Approach 1:
A phase synchronizing circuit is introduced as an intermediary between the position detector and the inverter circuit. This circuit synchronizes the phase of the positional signal with the rotational position of the magnetic rotor, correcting errors caused by Hall IC arrangement deviations. The synchronizing circuit acts as a mediator that transforms the erroneous positional signal into accurate phase information for sine wave generation, thereby eliminating noise while maintaining cost-effectiveness.
Solution Approach 2:
The system implements feedback by detecting the actual rotational position of the magnetic rotor and comparing it with the positional signal from the Hall IC. The phase synchronizing circuit adjusts the phase of the generated sine wave based on this feedback, compensating for arrangement errors in real-time. This feedback mechanism ensures that even with positional signal errors, the motor rotates smoothly without noise or vibration.
2Measurement precision
If the positional signal changing cycle varies due to arrangement errors, then frequency multiplication generates variable frequency clock pulses, but this causes discontinuous sine wave deformation and uneven rotation
Solution Approach 1:
The phase synchronizing circuit dynamically adjusts the phase of the generated sine wave in real-time based on the actual rotational position of the magnetic rotor. When the positional signal cycle varies due to Hall IC arrangement errors, the synchronizing circuit compensates by changing the phase accordingly, ensuring the sine wave remains continuous and smooth. This dynamic adjustment prevents discontinuous deformation and maintains stable motor rotation.
3Object-affected harmful factors
If a high-resolution encoder is used to detect rotor position with high precision, then sine wave driving can be achieved with minimal noise and vibration, but the cost increases significantly
Solution Approach 1:
The phase synchronizing circuit serves as an intermediary that bridges the gap between the low-cost Hall IC position detector and the high-performance sine wave driving requirement. By synchronizing the phase of the positional signal with the actual rotor position, it achieves the same noise-reduction effect as a high-resolution encoder would provide, but without the high cost. This intermediary component enables cost-effective implementation of smooth sine wave motor control.
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 suppresses noise and vibration while maintaining high-resolution positional accuracy, reducing the reliance on expensive high-resolution encoders and minimizing the influence of positional signal errors, thereby ensuring precise and stable motor rotation.
Implementation Method 1
The position detector generally includes three hall ICs, arranged so that the signal level of a positional change signal changes at every electrical angle of 60 degrees
Implementation Method 2
a non-brush motor having coils of three phases arranged at phase intervals of 120 degrees
Implementation Method 3
a magnetic rotor having permanent magnets with S and N poles alternately arranged
Data Source
AI summary
A motor drive controller includes a position detector that detects and outputs positional signals representing rotational positions of the magnetic rotor at first resolution, a position change detector that detects and outputs position change signals representing rotational positions of the magnetic rotor at second resolution higher than the first resolution, a phase synchronizing circuit that generates and outputs low resolution absolute phase information based on the positional and position change signals. The phase synchronizing circuit generates and outputs high-resolution absolute phase information based on the position change signals. A drive voltage signal outputting device outputs a drive voltage signal causing the current to flow through the coils in accordance with the absolute phase information.