A magneto-optical current measurement system based on the Faraday effect is evaluated for measuring fast pulse currents in high power applications. The current measurement system is based on the interaction of the magnetic field, generated by the current, and a beam of light propagating through magneto-optical material which is in close proximity to the current conductor. A high local magnetic field per ampère current inside the optical path is required to improve the accuracy and the sensitivity of the optical current measurement sensor.In this paper, the relation between the conductor geometry and the local magnetic field distribution is analytically modelled resulting in the geometry factor Kg. The analytical model enables an optimisation of the busbar geometry to increase the overall probe sensitivity and the accuracy of the optical current measurement system.
In this paper, a novel model predictive control (MPC) scheme is proposed for buck-boost converters for achieving a high control bandwidth over wide operating ranges. There, the duty cycles of the four possible switching states are considered as control inputs, such that an exact state propagation can be accurately predicted in a large-signal linear model. Unlike conventional methods, which suffer from poor dynamic control performance when the input voltage is close to the output voltage, the proposed method achieves good dynamic and steady-state control performance independent of the operating point by actively utilizing all four switches during transients and switching only two switches during the steady-state. The resulting quadratic programming (QP) problem enables a real-time implementation of the proposed MPC method at a fast sampling rate.
The transformer leakage inductance is one of the limiting factors for pulse shape quality in high voltage pulsed power (HVPP) applications such as cancer treatment, particle accelerators, and free electron lasers. Cone winding matrix (CWM) transformers are commonly used in HVPP applications as they offer low leakage inductance, low parasitic capacitance, high power density, and high insulation distance. This paper proposes an analytical Triple-2D leakage inductance model for CWM transformers. The model is based on a 2D model applicable to tilted cone windings which is derived by analytically integrating the magnetic potential. The Triple-2D modelling concept enables high accuracy and versatility. The model is verified with 2D FEM simulations and measurements on an existing pulse transformer for the compact linear collider at CERN. The analytical model is not only accurate and generally applicable but also rapidly executable enabling its time-efficient integration in optimisations.
A new method based on approximating 2D curved field lines by straight field lines with a piece-wise linear amplitude for calculating the HF-losses in Litz wire caused by a 2D magnetic field in the core window is presented in this paper. The error of the proposed method is less than 5% for the considered transformer cases which is much smaller than the typical error of known 1D-field winding loss models (10% − 30%). The computation time of the proposed method is in the range of a few milliseconds and thus suitable for converter optimization routines.
This paper presents an optimization procedure for a transformer-based solid-state pulse modulator with an additional damping network at the load. The design of the pulse transformer and the damping network are combined in the procedure, so that pulses with pulse lengths in the µs-range with a fast rise time and a compact transformer volume can be achieved.
