Abstract: A converter connection for conversion between alternating voltage and direct voltage, for connection to a power network (DCN) having a neutral pole (P0) and at least one pole (P+,P-) energized by direct voltage in relation to the neutral pole, comprises a voltage-source converter (VC) with two direct-voltage terminals (DP, DM). At least one of the direct-voltage terminals of the converter is connected by means of an electric pole conductor (W1, W12, W11, W21, W2) to at least one of the poles of the power network which are energized by direct voltage.

Abstract: A power supply for providing, from a low voltage source, a high voltage supply for a display device comprises first and second physically separate modules and an electrical conductor therebetween. The first module is adapted to be connected to the low voltage source and contains circuitry operating at low voltage. The second module provides said high voltage supply and contains circuitry operating at high voltage. The electrical conductor between the two modules carries current only at low voltage. This arrangement permits safe disconnection of the power supply, for instance in emergency situations, by breaking the low voltage connection, rather than having to break a high voltage connection. A preferred use of the power supply is to provide a high voltage supply to a display device incorporated into a helmet.