Objective 

Test and characterize power train of electrical traction drives in the power range up to 250 kW, with dc voltage supply up to 4 kV.

Short description

The test-bench is mainly composed of 1MW medium voltage ac-dc electrical substation with a dc-voltage regulation up to 4 kV and maximum dc-current of 250 A .  The primary ac-feeder is composed of a three-phase three-winding transformer 9kV/400V.  Each secondary winding supplies a group of ac/ac conversion with a dc-intermediate stage. Each group consists of thyristor unidirectional rectifier whose feeds two inverters connected in parallel. The ac output of each inverter feeds one of the two primary windings of a further three-phase three-winding transformer with transformation ratio unit. The ac outputs of the two groups are arranged in series via two half-windings which feed off respectively the secondary of two three-phase three-winding transformers 400V/1000V which outputs are rectified by individual rectifiers diodes. Each diode-rectifier can be arranged in series or in parallel in order to get the desired dc voltage. The test bench is completed with a 180 kW asynchronous electrical drive that works as a brake with a maximum speed of 4500 rpm and maximum torque of 200 Nm.