A high voltage generating device includes a booster and a driver. The booster includes first and second inductors connected in series and a capacitor connected in parallel to the first inductor. One end of the first inductor is connected to a DC voltage. The driver is connected in series to the second inductor and performs a switching operation by a driving signal. An inductance L2 of the second inductor is larger than an inductance L1 of the first inductor. The driver performs the switching operation at the driving frequency f of the driving signal within f0ff1. The f0 is a resonance frequency by the first inductor and the capacitor, and the f1 is a resonance frequency by the capacitor and the first and second inductors. The booster is driven by the driver and generates a sine wave AC high voltage higher than the DC voltage.

A modular braking adjuster includes a brake resistor and at least two sub-modules arranged in series. At least one sub-module is constructed as a full-bridge module and at least one sub-module is constructed as a double half-bridge module. A control device is configured to generate a voltage across the serially connected sub-modules, wherein the voltage has a direct voltage component and an alternating voltage component. The control device provides open-loop or closed-loop control of the alternating voltage component, such that the alternating voltage component is at least temporarily greater than the direct voltage component and the time-averaged energy taken up by the modular braking adjuster is converted into heat in the brake resistor. An electric drive having the modular braking adjuster and a power converter electrically connected on the direct voltage side to the modular braking adjuster and a method for operating a modular braking adjuster are also disclosed.

There is disclosed herein a converter valve assembly (20) for a power grid system, comprising two or more equal groups (6a, 6b, 6c) of prismatic converter cells (3a-ad), each group (6a, 6b, 6c) being arranged in a respective plane (7a, 7b, 7c) of a plurality of parallel planes spaced apart along a horizontal axis (8). Converter cells (3a-j) in a group (6a) are connected in series, and the groups (6a, 6b, 6c) are connected in series along the axis (8). The prismatic converter cells (3a-j) in a group (6a) are arranged such that there is a corresponding voltage difference between each converter cell (3a-j) in the group (6a) and each corresponding converter cell (3k-t) in an adjacent group (6b) that is a spatially nearest to said each converter cell (3a-j), during operation of the converter valve assembly (20). Therefore, a spacing between groups may be reduced and an overall volume of the converter valve assembly may be reduced.