Rotating Machine Control Apparatus Harmonic Current Superimposition
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Solution Overview
Problem
Existing control apparatuses for rotating machines fail to effectively reduce fluctuations in electromagnetic forces, leading to increased noise due to resonance with the motor's resonant modes, particularly when harmonic currents are superimposed to suppress higher-order electromagnetic forces, which can inadvertently increase lower-order noise-causing forces.
Innovation Solution
A control apparatus that superimposes specific harmonic currents on the fundamental wave current to convert higher-order electromagnetic forces away from resonant modes, thereby reducing noise by separating their angular velocities from the resonant frequencies, using a combination of harmonic voltage calculation and superimposition units within a power conversion circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If magnetic flux distribution is shaped into a sinusoidal wave to reduce electromagnetic force fluctuations, then electromagnetic force stability is improved, but high-precision manufacturing control is required
Solution Approach 1:
The invention replaces the mechanical/manufacturing approach of shaping magnetic flux distribution with a control-theory approach. Instead of physically modifying the motor structure to achieve sinusoidal magnetic flux distribution, the invention uses electrical control by superimposing harmonic currents to achieve the same effect of reducing electromagnetic force fluctuations, thereby avoiding high-precision manufacturing requirements.
2Object-affected harmful factors
If a vibration control member is provided in the vibration transmission portion to reduce noise, then electromagnetic force fluctuation is suppressed, but the number of components and manufacturing cost increase
Solution Approach 1:
The invention makes the control system self-sufficient by using the existing power conversion circuit to generate harmonic currents for noise suppression. The power conversion circuit, which is already necessary for motor control, is utilized to also generate the harmonic currents needed for electromagnetic force fluctuation suppression, eliminating the need for separate vibration control members and reducing overall system complexity.
3Object-affected harmful factors
If harmonic currents are superimposed to reduce electromagnetic force fluctuations, then noise is reduced, but the control system complexity increases
Solution Approach 1:
The invention makes the power conversion circuit multi-functional by having it perform both the primary function of motor control and the secondary function of generating harmonic currents for noise suppression. This universal approach allows one component to serve multiple purposes, avoiding the need for additional dedicated noise control components and minimizing the increase in control system complexity.
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 effectively reduces noise in rotating machines by ensuring that the converted electromagnetic forces have angular velocities significantly different from the resonant modes, thereby minimizing noise levels even when operating near resonant frequencies.
Implementation Method 1
a power conversion circuit electrically connected to the rotating machine to apply a voltage to the winding wire
Implementation Method 2
an electromagnetic force acting on the rotating machine and having the fluctuating angular velocity obtained by multiplying the fundamental angular velocity by the integer is defined as a K-th order electromagnetic force
Data Source
AI summary
A control apparatus, for a system including a rotating machine having a stator, around which a winding wire is wound, and a power conversion circuit, includes: a superimposition device that superimposes multiple harmonic currents, for converting a first electromagnetic force to a second electromagnetic force, on a fundamental wave current, the first electromagnetic force being a second or higher order electromagnetic force as a reduction object, the second electromagnetic force being a second or higher order electromagnetic force and different from the first electromagnetic force, an order of each harmonic current being between the first electromagnetic force and the second electromagnetic force; and a manipulation device that operates the power conversion circuit to flow the fundamental wave current, on which the harmonic currents are superimposed, in the winding wire.