Synchronizing Inverter Switching Frequencies to Limit Electromagnetic Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The interaction between two independent inverters connected to the same DC capacitor in electric vehicles leads to strong, non-repeatable, and non-systematic disturbances, making validation and certification complex due to the lack of synchronization in existing technologies.
Innovation Solution
A control system comprising a first and second control means for the inverters, each emitting a chopping signal modulated in pulse width synchronization, facilitated by an internal clock, to synchronize the switching frequencies and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two independent inverters are used to power electric traction machines, then the vehicle can achieve better performance and reliability, but strong electromagnetic interactions and non-repeatable disturbances occur between the inverters
Solution Approach 1:
The patent merges the timing control of two independent inverters by synchronizing their switching operations to the same clock signal. This coordination reduces electromagnetic interactions between the inverters while maintaining their operational independence for performance and reliability benefits.
2Adaptability or versatility
If inverters operate with independent control and different switching frequencies, then each inverter can be optimized independently, but validation becomes complex due to non-systematic disturbances
Solution Approach 1:
The patent implements periodic synchronized switching actions for both inverters based on a common clock signal. This periodic coordination makes disturbances systematic and repeatable, occurring at predictable intervals that facilitate validation and certification while preserving inverter control flexibility through adjustable duty cycles.
3Device complexity
If the same clock signal is used to synchronize both inverters, then electromagnetic interactions are reduced and validation is simplified, but the inverters lose independent control capability
Solution Approach 1:
The patent segments the control of each inverter into two parts: synchronized timing control from a common clock signal for reducing electromagnetic interactions, and independent duty cycle control for maintaining operational flexibility. This segmentation resolves the contradiction by separating timing coordination from power control.
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 synchronization limits electromagnetic interference, simplifies debugging, and ensures repeatable and predictable disturbances, facilitating validation and certification processes.
Implementation Method 1
an internal clock capable of emitting a synchronization signal, the first control means being capable of emitting a switching signal to the first inverter, pulse width modulated synchronized with the synchronization signal, the second control means being capable of emitting a switching signal to the second inverter, pulse width modulated synchronized with the synchronization signal
Data Source
Figure 1~2
AI summary
System for controlling the electrical supply of an electric automotive vehicle furnished with at least two electric traction machines (3,5), each supplied by an inverter (2,4), the inverters (2,4) being connected to one and the same continuous capacitor (6). The control system comprises a first control means (7) for controlling a first inverter (2) and a second control means (S) for controlling a second inverter (4), an internal clock (9) able to emit a synchronization signal, the first control means (7) being able to emit a chopping signal destined for the first inverter (2), pulse width modulated and synchronized with the synchronization signal, the second control means (8) being able to emit a chopping signal destined for the second inverter (4), pulse width modulated and synchronized with the synchronization signal.