Abstract: An inverter arrangement for generating a three-phase AC output voltage is provided with three pulse-controlled, free-running single-phase inverters. The inverters are connected at their inputs to a DC voltage source, and at their outputs to respective low-pass filters. The low-pass filters are connected to corresponding single-phase transformers, each having an output winding. The output windings of the single-phase transformers are connected to one another in a Y-circuit configuration to produce the output AC voltages, having a grounded neutral terminal. Each of the single-phase inverters is controlled by an associated pulse control device which contains a vector-oriented control device and a control unit. A vector oscillator generates signals corresponding to a symmetrical three-phase system of reference vectors for the vector-oriented control devices.

Abstract: A protected converter arrangement having electronic power circuitry using controlled valves and electronic information-processing control circuitry. The electronic power circuitry is provided only once, but the electronic information-processing circuitry is redundant and contains at least two complete control units. One unit leads and controls the electronic power circuit and at least one other unit operates in parallel, in standby condition. A monitoring device is associated with the control units and, in the event of a disturbance in the leading control unit, switches control of the electronic power circuit to an undisturbed control unit. The arrangement is especially suitable for use in protected converter arrangements which provide interruption-free supply of a load, having the advantage that the expensive electronic power circuitry is provided only once and is not operated in partial-load operation.