Motor Drive Carrier Frequency Prediction for EMI Noise Suppression
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Solution Overview
Problem
Existing motor drive systems struggle to dynamically adjust the carrier frequency to minimize electromagnetic interference (EMI) noise, especially when a vehicle encounters steep gradients, leading to potential negative impacts on other equipment.
Innovation Solution
A motor drive device with a processor that predicts torque demand and adjusts the carrier frequency by shifting boundary positions between sub-regions in the drive region of the motor, lowering the carrier frequency at peak torque demand to reduce EMI noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the carrier frequency is adjusted based on actual torque demand, then EMI noise can be reduced, but the system cannot respond in time when torque demand increases suddenly
Solution Approach 1:
The system predicts future torque demand based on current motor state (rotation speed, torque) and pre-adjusts the carrier frequency before the torque demand actually increases. This preliminary action allows the carrier frequency to be changed in advance, avoiding EMI noise generation during sudden torque demands while maintaining fast response capability.
2Device complexity
If the carrier frequency is kept constant, then the control system is simple, but EMI noise cannot be suppressed during high torque demand
Solution Approach 1:
The system dynamically changes the carrier frequency parameter based on predicted torque demand. By using a prediction model that estimates future torque requirements from current motor state, the system adjusts the carrier frequency to avoid EMI noise frequencies while maintaining manageable control complexity through algorithmic parameter adaptation.
3Object-affected harmful factors
If the carrier frequency is changed frequently, then EMI noise can be minimized, but system stability may be compromised
Solution Approach 1:
The prediction model anticipates torque demand changes and triggers carrier frequency adjustments only when necessary, based on predicted future states. This preliminary action approach avoids unnecessary frequent changes by only adjusting the carrier frequency when the prediction indicates upcoming high torque demand that would generate EMI noise, thereby maintaining system stability.
Data Source
AI summary
A motor drive device that includes: a power control unit that drives a motor, which configures a motive power source of a moving body, by supplying a drive signal modulated according to a carrier frequency; a memory; and a processor that is coupled to the memory, the processor being configured to: predict torque demand on the motor, and change the carrier frequency of the power control unit in a case in which an increase in the torque demand on the motor has been predicted.