Electric Motor Signal Sequence Varying Duration for EMI Reduction
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Solution Overview
Problem
Existing electric motor control systems face challenges in minimizing electromagnetic radiation and maintaining the integrity of modulated information due to the constant frequency of signal sequences, which leads to inefficient energy distribution and difficulty in determining the original signal sequence.
Innovation Solution
The electric motor generates a signal sequence with varying signal durations, using a combination of random number generators and tables to distribute energy across a wide frequency spectrum, while ensuring the original information can be determined and maintaining a constant signal block duration for synchronization purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the signal duration of individual signals is varied to distribute electromagnetic energy across multiple frequencies, then electromagnetic radiation is reduced, but the complexity of determining the original signal sequence increases
Solution Approach 1:
The signal duration is made dynamically variable within defined limits rather than fixed, allowing random or semi-random variation that spreads electromagnetic energy across multiple frequencies while maintaining determinability through the constrained variation range and signal block structure
Solution Approach 2:
The duration parameter of signals is changed within a defined range to achieve frequency spreading, while the signal block duration remains constant to maintain synchronization and enable original signal reconstruction
2Object-generated harmful factors
If the signal duration is varied to achieve frequency spread, then electromagnetic emissions are reduced, but the ability to retain and determine original information is compromised
Solution Approach 1:
The signal duration is varied only within defined limits rather than completely randomly, applying partial variation that achieves frequency spreading while preserving enough structure to allow original information recovery
Solution Approach 2:
The signal sequence is segmented into signal blocks with constant duration, where individual signals within blocks can vary in duration. This segmentation allows variation for frequency spread while maintaining block-level structure for information recovery
3Reliability
If additional hardware or software components are added to generate clock signals for synchronization, then signal synchronization is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The signal block structure serves multiple functions: it carries control information for motor control, provides synchronization through constant block duration, and enables clock signal generation without requiring separate hardware or software components
Solution Approach 2:
The clock signal function is merged with the control signal sequence by using the constant-duration signal blocks as the clock reference, eliminating the need for separate clock generation hardware or software
Data Source
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Figure 5
AI summary
The invention relates to an electric motor (1), in particular a fan motor, comprising a device (5) for generating a sequence (3) of signals that comprises a plurality of especially blocks (22) of signals. The blocks (22) of signals comprise a plurality of signals (19) having a specific signal duration (20). According to the invention, the signal duration (20) of the individual signals (19) varies.