Rotary Machine Noise Reduction via Conduction Period Control
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Solution Overview
Problem
Existing control apparatuses for rotary electric machines complicate control by manipulating both conduction phase and period to reduce electromagnetic-force distortion at resonant frequencies, making noise reduction challenging.
Innovation Solution
A control apparatus that utilizes the conduction period as a manipulative variable to selectively connect DC power source terminals to the rotary electric machine, setting the conduction period based on rotational speed to reduce electromagnetic-force distortion, specifically targeting resonant frequencies by adjusting the conduction period to zero higher harmonics voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If both conduction phase and conduction period are controlled to reduce electromagnetic-force distortion, then noise reduction is achieved, but control complexity increases
Solution Approach 1:
The invention extracts the conduction period control from the combined phase-period control approach, using only conduction period as the manipulative variable. This simplifies the control system by removing the need to simultaneously manage both conduction phase and conduction period, while still achieving effective reduction of electromagnetic-force distortion at resonant frequencies
Solution Approach 2:
The invention changes the control parameter from a combination of conduction phase and conduction period to solely conduction period. By adjusting the conduction period based on rotational speed and resonant frequency detection, the system achieves noise reduction through this single parameter change, avoiding the complexity of multi-parameter control
2Object-generated harmful factors
If conduction period is adjusted to reduce higher harmonics voltage, then electromagnetic-force distortion is reduced, but control precision requirements increase
Solution Approach 1:
The invention implements feedback control by detecting the rotational speed of the rotary electric machine and using this information to determine the appropriate conduction period. The control apparatus continuously monitors operating conditions and adjusts the conduction period accordingly, creating a closed-loop system that maintains precision without requiring overly complex measurement mechanisms
Solution Approach 2:
The invention makes the conduction period dynamic by varying it according to rotational speed. Instead of using a fixed conduction period, the system adapts the conduction period to match operating conditions, which simplifies the control approach while maintaining the ability to reduce electromagnetic-force distortion across different operating ranges
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
Effectively reduces electromagnetic-force distortion by using the conduction period as a feedback control variable, simplifying the control process and minimizing noise levels, particularly at resonant frequencies, while maintaining a constant fundamental wave voltage magnitude.
Implementation Method 1
a DC-AC conversion circuit including a switching element so as to control a controlled variable of the rotary electric machine, the switching element selectively connecting a positive terminal and a negative terminal of a DC power source to respective terminals of the rotary electric machine
Implementation Method 2
to reduce electromagnetic-force distortion of which frequency component corresponds to a resonant frequency of the rotary electric machine
Data Source
AI summary
A control apparatus for a rotary electric machine includes: operating unit for operating a DC-AC conversion circuit including a switching element so as to control a controlled variable of the rotary electric machine, the switching element selectively connects positive and negative terminals of a DC power source to respective terminals of the rotary electric machine and conduction period setting unit, in response to a rotational speed of the rotary electric machine, for setting a conduction period during which the respective terminals of the rotary electric machine, and the positive and negative terminals of the DC power source are allowed to be electrically connected therebetween via the switching element. The conduction period setting unit set the conduction period as a manipulated variable so as to reduce electromagnetic force distortion at a frequency corresponding to a resonant frequency of the rotary electric machine.