vfd brake chopper

What is a Brake Chopper?​​

A ​brake chopper​ is a high-speed semiconductor switch (IGBT or MOSFET) integrated into a VFI system to manage regenerative energy. When the DC bus voltage exceeds a predefined threshold, the brake chopper activates, diverting excess energy through a high-power resistor. This process prevents overvoltage tripping, protects sensitive components, and ensures continuous operation.

​Dynamic Braking Unit: A ​dynamic braking unit​ is a subsystem that combines the brake chopper with a high-wattage resistor. It specializes in rapid energy absorption during motor deceleration, converting kinetic energy into heat while maintaining precise control over the braking process.

Advantages of Brake Choppers with Dynamic Braking Units​

• ​Overvoltage Prevention: Safeguards VFI capacitors, semiconductors, and connected equipment.
• ​Cost Efficiency: Avoids expensive grid-tied regenerative systems by locally dissipating energy.
• ​Precision Control: PWM modulation ensures smooth deceleration and adjustable braking torque.
• ​Compact Design: Modular architecture saves space in industrial enclosures.
• ​Versatility: Compatible with AC/DC drives, pumps, fans, and robotics.

• ​How It Works​

  1. ​Energy Detection: During deceleration, the VFI detects rising DC bus voltage caused by regenerative energy.
  2. ​Chopper Activation: The brake chopper switches the dynamic braking resistor into the circuit, diverting excess current.
  3. ​Energy Dissipation: The resistor converts kinetic energy into heat, stabilizing DC bus voltage.
  4. ​Deactivation: Once voltage returns to safe levels, the chopper disconnects the resistor.
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