Motor Drive PWM Frequency Control for Communication Noise
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Solution Overview
Problem
Conventional techniques fail to effectively mitigate motor noise interference with communication systems, particularly in smart entry systems, as they do not address the issue of electromagnetic noise characteristics and its impact on communication methods.
Innovation Solution
A motor drive control device that performs PWM control with a fundamental frequency set above the bandwidth of the communication system's radio frequency band, ensuring continuous harmonic components appear before and after the band, thereby minimizing noise interference, and is adjustable based on host device instructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the fundamental frequency for PWM control is set high to push harmonic components away from the radio frequency band, then noise interference with communication is reduced, but motor control performance and efficiency deteriorate
Solution Approach 1:
The patent dynamically adjusts the fundamental frequency for PWM control based on the operating state of the motor and communication requirements. By changing the frequency parameter adaptively, the system pushes harmonic components away from the radio frequency band when communication is active, while maintaining optimal control performance when communication is not required.
Solution Approach 2:
The system implements dynamic frequency adjustment where the fundamental frequency for PWM control is not fixed but varies according to communication needs and motor operating conditions. This dynamic approach allows the system to optimize both noise reduction and control performance at different operational states.
2Reliability
If the fundamental frequency for PWM control is set low to improve motor control performance, then motor control efficiency is improved, but harmonic components fall within the radio frequency band causing noise interference
Solution Approach 1:
The system changes the fundamental frequency parameter based on communication requirements. When communication in the radio frequency band is active, the frequency is adjusted to push harmonics away from this band. When communication is inactive, the frequency can be lowered to optimize motor control performance.
Solution Approach 2:
The system proactively adjusts the PWM frequency before communication interference occurs by detecting communication activity in advance. This preliminary adjustment prevents harmonic components from falling within the radio frequency band, thereby avoiding noise interference before it can affect communication.
3Device complexity
If a fixed fundamental frequency is used for PWM control, then device complexity is reduced, but adaptability to different communication frequency bands is poor
Solution Approach 1:
The control system implements dynamic frequency adjustment capability that adapts to different communication frequency bands. The fundamental frequency for PWM control is adjusted based on the specific radio frequency band in use, allowing the system to work with different communication standards while maintaining simple overall architecture.
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 effectively reduces motor noise interference with communication systems, ensuring compliance with EMC specifications and allowing for adaptable noise mitigation across varying radio frequency bands.
Implementation Method 1
performing PWM (Pulse Width Modulation) control of a motor
Implementation Method 2
harmonics of a fundamental frequency for PWM control of the motor are included in noise occurring from the motor
Data Source
AI summary
In accordance with one aspect of the present disclosure, a motor drive control device is a motor drive control device performing PWM (Pulse Width Modulation) control of a motor, wherein harmonics of a fundamental frequency for PWM control of the motor are included in noise occurring from the motor; the fundamental frequency for PWM control is larger than a frequency corresponding to a bandwidth of a predetermined radio frequency band a communication apparatus uses; and frequencies of continuous harmonic components of the fundamental frequency for PWM control appear before and after the predetermined radio frequency band.