PMSM Acoustic Noise Reduction via Harmonic Voltage Injection
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Solution Overview
Problem
Current vector control methods for three-phase permanent magnet synchronous motors (PMSMs) generate acoustic noise due to torque ripple caused by non-sinusoidal back electromotive force (BEMF) harmonics, which existing noise suppression techniques fail to adequately reduce.
Innovation Solution
The method involves injecting additional voltage components at frequencies corresponding to the 5th and 7th harmonics of the stator electrical frequency to compensate for these harmonics, which are calculated and applied downstream of the ISD and ISQ controllers, either on the rotor reference frame or the three-phase stator frame, to minimize torque ripple and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional vector control is used to produce sinusoidal voltages and currents, then motor operation is stable, but acoustic noise increases due to torque ripple from non-sinusoidal BEMF harmonics
Solution Approach 1:
The patent applies preliminary anti-action by injecting compensating voltage components at the 5th and 7th harmonic frequencies before these harmonics can generate significant torque ripple. The control method calculates the required compensating voltages based on the non-sinusoidal BEMF harmonics and adds them to the fundamental voltage components, thereby preemptively counteracting the harmful torque ripple and acoustic noise before they occur.
2Object-generated harmful factors
If additional voltage components are injected to compensate for harmonics, then acoustic noise is reduced, but control system complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a harmonic compensation module that acts as a mediator between the conventional vector control system and the motor. This module calculates and injects the necessary compensating voltage components at the 5th and 7th harmonics, effectively bridging the gap between simple sinusoidal control and complex harmonic cancellation without requiring complete redesign of the entire control system.
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 approach significantly reduces or eliminates audible noise by effectively compensating for the higher-order harmonics of the BEMF, improving motor operation without requiring a large current bandwidth, even with low-cost feedback devices.
Implementation Method 1
a method of driving a three-phase motor with reduced generation of acoustic noise due to torque ripple... the quadrature and direct components of the control voltage are corrected with additional components at the frequencies to be compensated
Data Source
AI summary
A method of controlling a synchronous motor that may include windings and a power driving stage coupled to the windings, may include using a feedback loop including using a feedback circuit coupled to the windings to generate current feedback components, using current controllers for generating respective voltage signals, and using an anti-transform circuit for generating control signals for the power driving stage. Using the feedback loop may include generating additional compensation signals for compensating the control signals, and adding the additional compensation signals from the current controllers by one of generating the additional compensation signals as quadrature and direct voltage compensation signals and adding them to the voltage signals to generate compensated quadrature and direct signals, and supplying the compensated quadrature and direct signals to the power driving stage by providing the compensated quadrature and direct signals to the anti-transform circuit.