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The paper gives a new measurement method of the parameters characterising the magnetic laminations for broadband low‐level signals defined at any operational point.

High frequency phenomena machines fed by PWM inverters are related to low‐level signals corresponding to minor hysteresis loops around the instantaneous working point, which moves on the main loop at the basic frequency. The minor loops are assimilated to ellipses, which are characterised by only two parameters: the incremental magnetic permeability (μ) and the electric conductivity (σ).

For small signals high frequency field components, the laminated steel behaviour can be described by two local parameters (μ, σ) and skin effect. The values of μ and σ do not depend on frequency up to 1 MHz, but only on the operating point.

The proposed broadband characterisation should be associated with a Priesach model that defines the operating point for computer simulation of high frequency phenomena.

The broadband characterisation of magnetic laminations is useful for studying the behaviour of the windings of the PWM‐fed machines.

Broadband measurements are now possible on small magnetic steel lamination samples.

Self-commuted voltage source converter (VSC) can significantly extend the flexibility and operability of an HVDC system and be used to implement the concept of multi-terminal HVDC (MTDC) grid. To take full advantage of MTDC systems, its overall behaviour must be characterized in quasi static and dynamic states. Based on the numerous literatures, a dedicated two-level VSC model and its local controllers and DC grid voltage regulators are developed for this purpose. Furthermore, the requirement of the system to guarantee all the physical constrains must be well assessed and concrete demonstrations must be provided by numerical simulations.

First, a two-level VSC model and its local controllers and DC grid voltage regulators are developed. Then, DC cable models are investigated and their characteristics are assessed in the frequency domain. Those developed models are combined to form a three-terminal HVDC grid system on Matlab/Simulink platform. To analyze the stability of this electrical system, the dynamics of the system against variations of power dispatch are observed.

To analyze the stability of this electrical system, the dynamics of the system against variations of power dispatch are observed. The differences in the DC grid voltage dynamics and the power flow of the converter stations coming from the embedded primary controls are analysed, and the technical requirements for both cases are assessed.

In this paper, the dynamic stability of an MTDC system has been analysed and assessed through an adequate simulation model, including its control scheme and the cable models. The interest of the improved PI model for cables is highlighted.

The purpose of this paper is to present a method for computing voltage spikes endured by the insulation of the first coils of high-temperature (HT°) synchronous machines fed by PWM inverters that deliver fast-fronted voltage pulses.

The transient state following each steep edge is computed by SPICE using the global high-frequency (HF) equivalent circuit of the motor winding. This equivalent circuit is automatically built using the proposed elementary coil model. Two inorganic HT° technologies are compared: the first one uses a round copper wire insulated by a thin ceramic layer and the second one is made with an anodized aluminum strip.

The winding made with an anodized aluminum strip, which has a higher turn-to-turn capacitance, yields a better voltage distribution between coils of the machine.

The elementary coil equivalent circuit is computed from impedance measurements performed on an elementary coil. Another starting point could be developed with an FE analysis to determine the parameters of the HF equivalent circuit, which would avoid the need for a prototype coil before the machine design.

For inorganic motors, the insulation layers have poorer electrical characteristics compared with standard organic ones. Therefore, the computation of voltage spikes distribution along the coils of each phase represents a major issue in the design of HT° machines.

The presented approach is a step toward the design of HT° (400-500°C) actuators fed by PWM inverters based on fast SiC electronic switches.