Motor Harmonic Current Control for Vibration Suppression
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Solution Overview
Problem
Conventional motor control systems fail to effectively cancel out spatial and temporal harmonics, leading to motor vibrations due to non-uniform magnetic flux density and armature current oscillations.
Innovation Solution
A motor control system that employs harmonic superimposition processing, using a control device to superimpose a harmonic current on the field current based on motor operation indices to cancel out harmonics, with a waveform table stored in the control device to facilitate rapid determination of the harmonic currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If slots for accommodating armature windings are provided intermittently along the circumferential direction of the stator, then the motor structure is simplified and easier to manufacture, but the magnetic flux density becomes non-uniform and spatial harmonics are generated causing vibrations
Solution Approach 1:
The invention changes the parameter of field current by superimposing a harmonic component with specific frequency and amplitude onto the basic field current. This parameter modification allows the magnetic flux density distribution to be adjusted, thereby canceling out the harmful spatial harmonics generated by the intermittent slot structure while maintaining the simplified manufacturing approach
2Object-affected harmful factors
If harmonic superimposition processing is performed to cancel out harmonics and suppress vibrations, then motor vibrations are reduced, but the control system complexity increases and energy loss increases
Solution Approach 1:
The invention applies partial action by superimposing only the specific harmonic components that cause vibrations, rather than attempting to eliminate all harmonics. The harmonic superimposition is performed selectively with optimized amplitude and frequency, achieving sufficient vibration suppression while minimizing the additional energy consumption and control complexity
Solution Approach 2:
The control device dynamically adjusts the parameters of the superimposed harmonic current based on motor operating conditions. By modifying the amplitude and frequency of the harmonic component according to real-time operational parameters, the system achieves effective vibration cancellation while optimizing energy efficiency and avoiding excessive energy loss
3Object-affected harmful factors
If the control device determines harmonic characteristics based on motor operation indices to generate canceling harmonic current, then vibration suppression effectiveness is improved, but the control processing time and computational complexity increase
Solution Approach 1:
The control device performs preliminary determination of harmonic characteristics by utilizing pre-established relationships between motor operation indices and harmonic components. By preparing the harmonic cancellation strategy in advance based on operational parameters, the system achieves rapid response without requiring complex real-time calculations, thus reducing control processing time while maintaining vibration suppression effectiveness
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
The system effectively suppresses motor vibrations by partially canceling out harmonics, improving control response speed and reducing energy loss by executing harmonic superimposition only when necessary.
Implementation Method 1
a rotating magnetic field is generated by an armature current (three-phase alternating current) flowing over the armature winding. In the rotor, a direct current magnetic field is generated by a field current (direct current) flowing over the field winding
Data Source
AI summary
A motor control system disclosed herein controls operation of a motor having a stator having one of an armature winding and a field winding and a rotor having the other of the armature winding and the field winding. The motor control system includes a first inverter that supplies an armature current to the armature winding, a second inverter that supplies a field current to the field winding, and a control device that controls the operations of the first inverter and the second inverter. The control device is configured to be capable of executing harmonic superimposition processing for at least partially canceling harmonics appearing in the motor by superimposing harmonic currents on the field current based on the motor operation index indicating the operation of the motor.