Input filters ensure the electromagnetic compatibility (EMC) of battery electric vehicles and plug-in hybrids. They protect sensitive downstream components, prevent overvoltage peaks or interference and increase system reliability - for a longer service life of the individual components. As the vehicle ages, input filters can fail, which can lead to damage to the high-voltage battery and the charging system. As MAHLE has been mass-producing input filters since 2011, the company can use its OE expertise to meet all technical requirements and provide solutions for its customers in this growing market.

Tasks Input filter:

  • EMC suppression: Suppresses electromagnetic interference from power electronics. Ensures compliance with international EMC standards (e.g. CISPR 25, ISO 11452).
  • Voltage filtering and stabilization: Smoothes out voltage waves from the AC or DC power supply. Protects sensitive downstream components.
  • Safety and reliability: Helps prevent overvoltage peaks or faults. Increases the reliability of the system and extends the service life of the components.
  • Grid compliance (for *OBC): Ensures that the vehicle draws a sinusoidal current, reducing distortion when charging from the grid.

The input filters come directly from MAHLE's original equipment and will initially cover Renault (Twingo, Zoe, Kangoo) and Smart models. MAHLE will launch input filters in two versions (low-pass and high-pass filters).

Recognize problems

Input filters can be damaged by overheating, vibrations or the ingress of moisture. The ageing of components such as capacitors can also disrupt proper functioning. Consequences: The vehicle does not pass the prescribed EMC tests or overvoltage peaks can damage the inverter, the OBC or other sensitive electronic parts.

For owners of high-voltage vehicles, a defect in the input filter is difficult to diagnose. The following indications can provide information during a workshop visit:

 

 

  • Charging problems: slow charging, charging interruptions or charging start errors.
  • Warning lights on the dashboard for drive, charging system or electrical system.
  • Unusual noises such as high-pitched whistling or humming during the charging process may indicate a filter fault.
  • Infotainment or radio interference: Distorted radio signals, screen interference or other electronic interference (while driving or charging).
  • Vehicle shuts down or has power loss: In rare cases, there may be voltage instability due to a defect in the input filter.
  • Overheating near the charging port.

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