Single Phase Brushless DC Motor Phase Synchronization
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Solution Overview
Problem
Single phase brushless DC motors face inefficiencies due to phase differences between coil current and motor back emf, leading to reactive power issues and wasteful energy consumption.
Innovation Solution
A motor control circuit with a Hall effect sensor, coil switching unit, driving unit, reverse current polarity detection unit, phase error detection unit, and phase control unit synchronizes the phase of the coil current with the motor back emf by detecting voltage variations at the coil assembly, eliminating the need for extra elements and reducing energy loss and overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current detection methods are used to monitor coil current phase, then current phase can be detected, but energy loss and overheating occur due to the detection elements being in series with the coil current
Solution Approach 1:
The patent uses voltage detection at the coil assembly terminal as an intermediary method to indirectly obtain current phase information. Instead of placing detection elements in series with the coil current, the invention detects the voltage at the coil terminal, which correlates with the current phase without requiring direct series connection. This intermediary approach eliminates the energy loss and overheating problems associated with conventional series detection methods.
2Productivity
If phase difference between coil current and motor back emf exists, then motor operation occurs, but reactive power problems and energy wastage occur
Solution Approach 1:
The patent implements a feedback mechanism where the detected voltage phase information is used to adjust the driving signal phase. The system continuously monitors the voltage at the coil terminal, determines the current phase, compares it with the back emf phase, and adjusts the driving signal to minimize the phase difference. This feedback control eliminates reactive power problems and energy wastage by ensuring optimal phase alignment between coil current and back emf.
Solution Approach 2:
The patent employs dynamic phase adjustment of the driving signal based on real-time voltage detection. The system dynamically changes the phase of the driving signal in response to detected voltage phase variations, allowing the motor to operate efficiently under varying conditions. This dynamic adjustment ensures continuous optimization of the phase relationship between coil current and back emf, eliminating energy wastage.
3Measurement precision
If extra detection elements are added to monitor coil current, then current phase detection is possible, but device complexity increases
Solution Approach 1:
The patent makes the coil assembly terminal voltage detection serve multiple functions: it provides both the driving voltage reference and the current phase detection information simultaneously. By detecting the voltage at the existing coil terminal (rather than adding separate detection elements), the system achieves current phase detection capability while reusing existing structural components. This multi-functional approach avoids increasing device complexity.
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 enhances the operational efficiency of single phase brushless DC motors by synchronizing the phase of the coil current with the motor back emf, reducing energy wastage and avoiding overheating issues associated with conventional current detection methods.
Implementation Method 1
The Hall effect sensor senses a position of the magnetic pole of a rotor of the motor to accordingly generate a Hall effect signal
Data Source
AI summary
A single phase brushless DC motor comprises a Hall effect sensor, a coil assembly and a motor control circuit which generating a driving signal to guide a coil current flowing through the coil assembly. The Hall effect sensor senses the magnetic pole of the rotor to accordingly generate a Hall effect signal. The motor control circuit outputs a current polarity reverse signal according to the voltage at one end of the coil assembly. The time when the current polarity reverse signal is generated corresponds to the polarity reverse time of the coil current. The motor control circuit adjusts the phase of the driving signal according to the polarity reverse time of the Hall effect signal and the time when the current polarity reverse signal is generated to synchronize the phase of the back emf of the single phase brushless DC motor with the phase of the coil current.