TECHTOP TD350 - Chapter 3 Product Overview; Basic Principle of Operation

TD350 Series VFD Product overview
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Chapter 3 Product overview
3.1 What this chapter contains
This chapter mainly introduces the operation principles, product features, layouts, nameplates and
model instructions.
3.2 Basic principle
TD350 series VFD is used to control asynchronous AC induction motor and permanent-magnet
synchronous motor. The figure below shows the main circuit diagram of the VFD. The rectifier
converts 3PH AC voltage into DC voltage, and the capacitor bank of the intermediate circuit stabilizes
the DC voltage. The inverter converts DC voltage into the AC voltage used by AC motor. When the
circuit voltage exceeds the maximum limit value, external brake resistor will be connected to
intermediate DC circuit to consume the feedback energy.
DC reactor
(+)
P1
PE
PE
Fig 3.1 Main circuit (VFDs of 220V 18.5–55kW; 460V ≥37kW)
(+)
(-)
PB
PEPE
Fig 3.2 Main circuit (VFDs of 220V ≤15kW; 460V ≤30kW)