Motor-Driven Compressor Inverter Filter for Common-Mode Noise Damping
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Solution Overview
Problem
Existing motor-driven compressors face challenges in improving the damping effect of noise reducing units, particularly in reducing common-mode and normal-mode noise in DC power before it is converted to AC power by the inverter circuit.
Innovation Solution
The motor-driven compressor incorporates a noise reducing unit that includes common-mode choke coils and a smoothing capacitor, arranged in a low-pass filter circuit. The common-mode choke coils feature annular cores with windings and conductors that generate magnetic flux to resist leakage flux, effectively damping noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a noise reducing unit with common-mode choke coils and smoothing capacitor is added to reduce common-mode and normal-mode noise, then noise reduction performance is improved, but device complexity increases
Solution Approach 1:
The patent combines the common-mode choke coils and smoothing capacitor into an integrated noise reducing unit that functions as both a common-mode filter and a low-pass filter. This merging of functions reduces the overall number of separate components needed while achieving both common-mode noise reduction and normal-mode noise suppression, thereby improving noise reduction performance without proportionally increasing device complexity
Solution Approach 2:
The noise reducing unit is designed to perform multiple functions simultaneously: it acts as a common-mode choke to suppress common-mode noise, and as a low-pass filter to suppress normal-mode noise. This multi-functionality allows a single component assembly to address multiple noise issues that would otherwise require separate solutions, resolving the contradiction between noise reduction effectiveness and device complexity
2Reliability
If the damping effect of the noise reducing unit is improved by adding conductors surrounding the windings, then resonance peak suppression is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent employs a nested structure where annular conductors are placed inside the windings of the common-mode choke coils. The conductors are positioned within the winding bobbins, creating a nested arrangement that maximizes the damping effect within the available space. This nesting approach enhances resonance suppression without requiring additional external components or complex assembly procedures, thereby improving reliability while maintaining ease of manufacture
Solution Approach 2:
The annular conductors are designed to automatically generate eddy currents in response to leakage flux from the windings, creating a self-regulating damping mechanism. This self-service feature eliminates the need for external control systems or complex adjustment mechanisms to achieve the desired damping effect, simplifying the manufacturing process while enhancing the reliability of resonance peak suppression
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 configuration enhances the damping effect, reducing resonance peaks and effectively suppressing common-mode and normal-mode noise, thereby improving the overall performance of the motor-driven compressor.
Implementation Method 1
The common-mode choke coils include a first coil and a second coil. The first coil includes an annular first core, a first winding wound around the first core, a second winding that is wound around the first core at a position away from the first winding so as to face the first winding, and an annular first conductor that extends over and surrounds the first winding and the second winding.
Implementation Method 2
The induced current in the conductor is converted into thermal energy, so that the conductor acts as a magnetic resistance, thereby producing a damping effect. This suppresses a resonance peak generated by the low-pass filter.
Data Source
AI summary
A motor-driven compressor includes an inverter device. The inverter device includes a noise reducing unit. The noise reducing unit includes common-mode choke coils and a smoothing capacitor. The common-mode choke coils include a first coil and a second coil. The first coil includes a first core, a first winding, and a second winding. The first core includes a first straight portion and a second straight portion. The second coil includes a second core, a third winding, and a fourth winding. The second core includes a third straight portion and a fourth straight portion. The first coil and the second coil are arranged side by side such that a current flowing through the first winding and the third winding generates an annular magnetic flux that passes through both of the first straight portion and the third straight portion.