Rotating Electric Machine Control Reducing Radial Force Variation
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Solution Overview
Problem
Mass-produced rotating electric machines exhibit variations in magnetic flux characteristics, leading to differences in the radial electromagnetic force acting on the rotor, which can cause vibration and noise due to unsuitable harmonic currents.
Innovation Solution
A control apparatus with a magnetic flux information acquiring unit, fundamental setting unit, and harmonic setting unit determines the appropriate harmonic currents to reduce the radial electromagnetic force variation by acquiring magnetic flux information and setting harmonic command values for each individual machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fixed harmonic currents are supplied to reduce radial electromagnetic force variation, then vibration and noise are reduced for machines with matching magnetic flux characteristics, but vibration and noise increase for machines with different magnetic flux characteristics
Solution Approach 1:
The patent applies parameter changes by adjusting the harmonic current parameters (amplitude and phase) based on the measured magnetic flux characteristics of each individual machine. The control apparatus determines optimal harmonic current parameters that match the specific magnetic flux waveform of each machine, thereby reducing radial electromagnetic force variation and vibration noise for that particular machine.
Solution Approach 2:
The patent implements feedback by measuring the actual magnetic flux characteristics of each machine using a magnetic flux detecting device, then using this measurement information to determine the appropriate harmonic current parameters. This closed-loop approach ensures that the harmonic currents are tailored to the specific machine's magnetic flux waveform, resolving the contradiction between fixed harmonic currents and individual machine adaptability.
2Object-affected harmful factors
If individualized harmonic currents are determined for each machine, then radial electromagnetic force variation is reduced for that specific machine, but the complexity of the control system increases
Solution Approach 1:
The patent applies preliminary action by measuring and storing the magnetic flux characteristics of each machine in advance during the manufacturing or commissioning phase. This pre-acquired information is then used to determine the optimal harmonic current parameters before the machine enters normal operation, avoiding the need for real-time complex calculations and measurements during operation.
Solution Approach 2:
The patent uses copying by creating a database or lookup table that stores the relationship between magnetic flux characteristics and optimal harmonic current parameters for different machine types. Once the characteristics are measured for a particular machine type, this information can be copied and applied to similar machines, reducing the need for individual measurements while still achieving individualized control.
3Object-affected harmful factors
If magnetic flux measurement and individualized control are implemented, then vibration and noise are minimized for each machine, but the manufacturing and setup process becomes more complex
Solution Approach 1:
The patent applies universality by designing a standardized control apparatus and measurement system that can be applied across different machine types and production batches. The magnetic flux measurement device and control algorithm are made universal, allowing the same system to handle various machine configurations, thereby reducing the complexity of manufacture and setup while still enabling individualized control.
Solution Approach 2:
The patent implements self-service by enabling each machine to undergo automatic magnetic flux measurement and harmonic current parameter determination during the setup or commissioning phase. The machine itself provides the necessary information through the measurement device, and the control apparatus automatically determines the optimal parameters without requiring extensive manual intervention or complex external equipment.
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 solution effectively reduces radial electromagnetic force variations on the rotor, minimizing vibration and noise across different rotating electric machines by tailoring harmonic currents based on unique magnetic flux characteristics.
Implementation Method 1
information on variation in an electromagnetic force acting on a stator core
Data Source
AI summary
In a control apparatus, a magnetic flux information acquiring unit acquires magnetic flux information of magnetic poles of a rotating electric machine. A fundamental setting unit sets a fundamental command value for supplying a fundamental current to a winding of the rotating electric machine. A harmonic setting unit sets, based on the magnetic flux information acquired by the magnetic flux information acquiring unit, a harmonic command value for supplying a reduction current to the winding. The reduction current is a harmonic current for reducing variation in a radial electromagnetic force acting on a rotor of the rotating electric machine. An operating unit operates, based on the fundamental command value set by the fundamental setting unit and the harmonic command value set by the harmonic setting unit, an electric power converter to supply the winding with a drive current that is obtained by superimposing the reduction current on the fundamental current.