Power converter for energy transmission

Method for operating a power converter, where said power converter comprises at least one main module to be actively supplied having input terminals for the application of an input voltage for said power converter and n−1 further modules, where n is an integer and n≥2 is true, where said at least the n−1 further modules are preferably four-quadrant modules and at least each of said n−1 further modules comprises an energy storage device, preferably a capacitor for storing charge, and comprises switching devices, preferably formed by transistors, for optional and controlled setting of at least one active normal operation, in which said respective module introduces the voltage at its energy storage device into the voltage path, a bypass operation, in which said respective module only connects through, and an inverted operation, in which said respective module introduces the voltage at its energy storage device inverted into the voltage path, and where the method comprises the following steps:

• connecting said n modules in series,
• applying a direct voltage U0 at said input terminals of said main module,
• predetermining a desired temporal course of the output voltage in relation to the amplitude over time,
• tapping the output voltage at the two endpoints of the series connection of said modules,
• maintaining predetermined states of charge for said individual modules in such a way that each module in its active operating state substantially makes a predetermined voltage contribution to the series connection, where said voltage contributions of said modules differ from each other and are preferably stepped down relative to each other by the powers of two,
• actuating said switching devices of said modules to switch each module to an operating state such that the sum of the individual module voltages as they are provided by said energy storage device of each module according to its active, inverted or bypass operation at all times corresponds to the predetermined range of the output voltage, where at least one alternative module configuration exists for each module configuration, that is currently predetermined by switching said individual switching devices of said modules and the resulting output voltage, with the exception of the module configurations for maximum (U0), minimum (−U0) and zero (0) output voltage, and that can be set and substantially leads to the same output voltage, where switching to this alternative module configuration allows modules, that are to be recharged for maintaining their desired state of charge, to be switched to the inverted operating state as part of said alternative module configuration and without changing the resulting output voltage level, in order to thus enable recharging said respective module while maintaining the same output voltage level.