Operation principle and hardware description 25Operation principle andhardware descriptionWhat this chapter containsThe chapter briefly describes the operation principle, layout, type designation labeland type designation information. It also shows a general diagram of powerconnections and control interfaces.Operation principleThe ACS355 is a wall or cabinet mountable drive for controlling asynchronous ACinduction motors and permanent magnet synchronous motors.The figure below shows the simplified main circuit diagram of the drive. The rectifierconverts three-phase AC voltage to DC voltage. The capacitor bank of theintermediate circuit stabilizes the DC voltage. The inverter converts the DC voltageback to AC voltage for the AC motor. The brake chopper connects the external brakeresistor to the intermediate DC circuit when the voltage in the circuit exceeds itsmaximum limit.Capacitorbank U2V2W2AC motorM3~Rectifier InverterBrake chopperU1V1W1BRK- BRK+AC supply/ Common DC terminals
