Current-Compensated Choke for Inverter Interference Suppression
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Solution Overview
Problem
Existing voltage converters, particularly in electric vehicles, face challenges in effectively and cost-effectively reducing common-mode interference voltages caused by pulse-controlled inverters, which can disrupt radio reception and other electromagnetic compatibility issues.
Innovation Solution
A current-compensated choke is placed on the input side of the inverter between the DC voltage source and intermediate circuit capacitor, minimizing common-mode interference and eliminating the need for costly multi-phase chokes on the output side, while Y-capacitors and RC elements are used to further suppress interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a common-mode choke is integrated into the connecting cable between the pulse inverter and the electrical machine, then interference voltage suppression is improved, but device complexity and cost increase due to requiring multi-phase chokes
Solution Approach 1:
The patent inverts the conventional approach by placing the common-mode choke on the DC input side of the inverter rather than on the AC output side connecting to the electrical machine. This inversion transforms a complex multi-phase choke requirement into a simple single-phase DC choke, dramatically reducing device complexity while maintaining interference suppression effectiveness.
Solution Approach 2:
The patent extracts the common-mode interference suppression function from the AC output side and relocates it to the DC input side. By separating the interference filtering function from the power conversion function, the solution eliminates the need for complex multi-phase chokes while achieving the same interference voltage suppression goal.
2Object-affected harmful factors
If a current-compensated choke is placed on the input side of the inverter, then interference voltage suppression is improved and device complexity is reduced, but additional components are required
Solution Approach 1:
The patent merges the common-mode choke with existing DC input components (DC link capacitor, Y-capacitors) into an integrated input filter assembly. By combining multiple filtering functions into a unified structure at the DC input, the solution achieves effective interference suppression without proportionally increasing the number of discrete components.
Solution Approach 2:
The DC input side components (DC link capacitor, Y-capacitors, and common-mode choke) serve multiple functions: voltage stabilization, electromagnetic interference filtering, and common-mode noise suppression. This multi-functionality reduces the need for separate dedicated components for each function.
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 effectively suppresses interference voltages in a cost-effective manner, improving electromagnetic compatibility and reducing noise emissions, particularly in the medium-wave frequency range, without the need for expensive multi-phase chokes on the output side.
Implementation Method 1
a current-compensated inductor 11 is coupled to a two-phase input of the inverter 10. The current-compensated inductor 11 comprises a first winding 11a and a second winding 11b
Implementation Method 2
Y-capacitors 13-1, 13-2 are provided between a reference potential and a terminal of the DC input 110 of the inverter 10
Data Source
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AI summary
The present invention relates to interference suppression of interference signals from an inverter. To this end, a current-compensated inductor is provided at the input end of an inverter, in particular a pulse-controlled inverter. This current-compensated inductor is preferably arranged between a DC voltage source and an intermediate circuit capacitor of the inverter. Polyphase inductors at the AC voltage output of the inverter can be dispensed with in this way.