Motor Phase Detection Using Lookup Table Memory
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Solution Overview
Problem
Existing phase detecting devices for motors face challenges in accurately detecting the phase of a rotor due to production tolerances, leading to phase detection errors, and require costly correction circuitry to minimize these errors.
Innovation Solution
A phase detecting device that includes a signal level detector, a level memory, and a phase detector, which detects a first level of a signal at predetermined intervals during constant speed rotation, stores this level as a second level, and uses this stored level to accurately determine the rotor's phase, thereby minimizing the effect of production tolerances without the need for correction circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction circuitry is added to minimize phase detection errors caused by production tolerances, then phase detection accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary action by pre-storing the relationship between signal levels and rotor phases in a lookup table during the manufacturing process. Instead of using complex correction circuitry to adjust for production tolerances during operation, the system performs the correction work in advance by storing characteristic data that directly maps signal levels to phase angles, eliminating the need for real-time complex calculations or correction circuits.
Solution Approach 2:
The patent uses copying by creating a digital representation (lookup table) of the rotor's magnetic field characteristics at different phases. Rather than physically correcting the magnetic field or using complex analog circuitry, the system copies the essential phase information into a stored data structure that can be quickly referenced during motor operation, simplifying the overall system architecture.
2Measurement precision
If correction circuitry is added to minimize phase detection errors caused by production tolerances, then phase detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies preliminary action by pre-storing the relationship between signal level and rotor phase in a lookup table during manufacturing. This approach shifts the complexity from expensive real-time correction circuitry to a simple data storage structure that can be implemented using basic memory components, significantly reducing manufacturing costs while maintaining high phase detection accuracy.
Solution Approach 2:
The patent replaces expensive, complex correction circuitry with a simple, inexpensive lookup table stored in memory. This lookup table acts as a disposable or reconfigurable data structure that provides the same functional benefit as complex hardware corrections but at a fraction of the cost, using basic memory cells instead of precision analog circuits.
3Measurement precision
If correction circuitry is added to minimize phase detection errors, then phase detection accuracy is improved, but circuitry area increases
Solution Approach 1:
The patent uses copying by transferring the phase detection function from physical correction circuitry to a digital lookup table stored in memory. This lookup table occupies minimal space compared to analog correction circuits and can be implemented using standard memory cells, dramatically reducing the circuitry area required for high-precision phase detection.
Solution Approach 2:
The patent applies mechanics substitution by replacing physical correction circuitry (analog/electronic hardware) with a data-based lookup table (information processing). This substitution transitions from occupying physical circuit board space with complex electronics to storing data in compact memory structures, reducing overall circuitry area while maintaining detection precision.
Data Source
AI summary
A phase detecting device includes a signal level detector configured to detect a first level of a signal according to a phase of a rotor of a motor, a level memory configured to store the first level of the signal preliminarily detected at each phase of the rotor as a second level of the signal at the phase of the rotor, and a phase detector configured to detect the phase of the rotor based on the second level of the signal inputted from the signal level detector.