Mr. Naveen

VFD back to back testing and different HMMC

Abstract of talk:

Topic Overview: Medium Voltage Drive Testing

Today, I’ll talk about a powerful validation technique—Back-to-Back Testing, or as I prefer to call it, Real-World Drive Simulation.

The Concept:

• Drive A is powered from the grid and drives Motor A.
• Motor A is mechanically coupled to Motor B.
• Motor B is connected to Drive B, which returns energy back to the grid.

This closed-loop system allows energy to circulate between both drives, with the grid supplying only the loss energy—primarily from:

• Transformer losses
• Inertia-induced delays
• IGBT switching losses

Why This Matters

This test rig allows us to replicate real-world scenarios and measure:

• Electromagnetic noise
• Switching performance
• Power losses and efficiency
• Maximum torque
• Drive control behavior under dynamic conditions