Electric Motor Sector Control for Single-Shunt Harmonic Reduction
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Solution Overview
Problem
The use of single-resistance current sampling in electric motors for household appliances leads to current distortion and increased harmonics, resulting in noise and unsatisfactory user experience due to traditional voltage vector sector switching algorithms.
Innovation Solution
A control method for electric motors that determines a target sector based on a theoretical sector, actual sector, and interval duration using SVPWM, generating a driving signal to suppress phase current distortion and reduce harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional voltage vector sector switching algorithm is used with single-resistance current sampling, then device complexity is reduced, but current distortion increases and harmonics increase
Solution Approach 1:
The patent changes the parameter of sector determination from theoretical calculation to historical actual sector reference. By using the actual sector from the previous control cycle and comparing it with the theoretical sector, the system adjusts the switching strategy to match actual motor behavior, thereby reducing current distortion and harmonics while maintaining single-resistance sampling simplicity
Solution Approach 2:
The patent implements feedback by using the actual sector obtained in the previous control cycle to inform the current control cycle's sector switching decision. This feedback mechanism allows the system to adapt to actual motor运行情况 and correct for distortions that would otherwise occur with purely theoretical sector switching
2Ease of operation
If traditional voltage vector sector switching algorithm is used, then control simplicity is maintained, but operation noise increases
Solution Approach 1:
The patent modifies the sector switching parameter strategy by introducing interval duration comparison. Instead of switching sectors at every control cycle boundary, the system compares the interval duration with a preset threshold to determine whether switching is necessary, thereby reducing unnecessary switching operations that generate noise while keeping the control algorithm relatively simple
Data Source
AI summary
A control method for an electric motor, an electric motor, and a computer-readable storage medium are provided. According to the method, in a current control cycle, a first theoretical sector corresponding to a voltage vector of an electric motor is determined; in the previous control cycle of the current control cycle, a first sector corresponding to the voltage vector is obtained; a target control cycle in multiple historical control cycles which precede the current control cycle is determined, and an interval duration between the target control cycle and the current control cycle is determined; a target sector corresponding to the voltage vector in the current control cycle based on the first theoretical sector, the first sector, and the interval duration is determined; and a corresponding driving signal based on the target sector is generated, and the electric motor is driven to operate based on the driving signal.