Transistor Inverters for Télécommunication Systems

Telecommunication systems used in France have their CPU powered by DC/DC converters. However, the peripherals have to be powered by AC current. So, they require inverters, the power of which is between 2 and 6 KVA. In order to obtain high performances, it has been chosen to use the quasi-square-waves adding principle. The power unit is a 1,5 KVA generator providing neither H3 nor H9 harmonics. Two of then constitue a 3 KVA inverter having no H5, four of them a 6 KVA inverter having neither H5 nor H7. The inverter is a cabinet which receives replaceable plug in modules; one for filtering and electronic circuits and others for power units. The outputs of the power units are made of 2 windings which are to be connected in series or in parralel. So, the same module may be used in a 3 or 6 KVA inverter.