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.
An accurate analytical switching loss model for a SiC MOSFET and Schottky diode half-bridge for a wide operating range is proposed in this paper, which is based on nonlinear differential circuit equations including parasitics. In the model, nonlinear device characteristics are used, including the dynamic gate-drain capacitance and the transfer characteristics measured under real switching conditions. With the proposed model, the accuracy improvement by using measured characteristics instead of device data sheet information is analyzed. In addition, the impact of making different common assumptions/simplifications on the accuracy of switching loss models is evaluated.
In this paper, the achievable cooling limits of passively cooled integrated motor drives are investigated. For the concept of a drive-integrated end cap with cooling fins a thermal model is derived and used to calculate the cooling system performance index, resulting in a range of CSPI = 0.67..1.8WK−1 L−1 which is primarily suitable for high-torque, low-speed motors.
This paper proposes a novel strategy of control and modulation in an isolated single-stage Dual Active Bridge Series-Resonant (DABSR) DC-AC converter specifically for solar photovoltaic arrays connected to a single-phase grid (PV2SPG). The Perturb and Observe (P&O) maximum power point tracking (MPPT) algorithm is implemented and analyzed considering the influence of the low-frequency ripple on the PV side. Aiming to compensate the PV voltage, which varies with the temperature, a duty ratio (DR) control is introduced. Besides, the power flow is controlled by phase shift modulation. The DC-AC converter is compared with an analogous DABSR DC-DC converter that does not have the low-frequency ripple problem to validate the proposed control and modulation. The result simulations validate the proposed control and modulation.
For modelling and optimizing gapped high-frequency inductors, the calculation of eddy current losses in foil windings due to the two-dimensional fringing field caused by air gaps in the core is important. The winding loss models must offer a high accuracy when calculating the 2D field distribution and must be computationally efficient in order to enable several thousand calculations required during the optimization. This article proposes an analytical model based on the magnetic vector potential formulation that can predict the eddy current losses in foil windings due to the fringing field of an arbitrary number of air gaps. The analytical model is combined into a closed-form loss formula and verified by FEA simulations.
Power-Hardware-in-the-Loop (PHiL) system for electric drives application based on power converter with Field Programmable Gate Array (FPGA)-based control system is discussed. PHiL structures are under discussion as well. During the PHiL mathematical model analysis instantaneous current repeating quality is increased. Variable frequency drive (VFD) was selected for testing.
This paper analyzes the equivalent model of MMC with integrated BESS and designs the control structure based on voltage source mode at battery side. The optimized multi-level state of charge (SoC) balancing scheme and battery current control strategy are proposed. The experimental results validate the effectiveness and feasibility of the proposed control strategy.
In this paper, submodules fault-tolerant control and analysis of Modular multilevel converter(MMC) with integrated battery energy storage system(BESS) are performed under hot reserve. A capacitor control strategy based on the average of the capacitor voltages, which is suitable for both normal operation and submodules fault-tolerant operation is proposed. Besides, difference currents are controlled flowing internally to ensure that the system's external characteristics remain unchanged before and after submodules fault. Then the influence of submodules fault on the arm current is analyzed by Monte Carlo simulation, and the conclusion that the maximum and RMS of the arm current will not exceed 1.1 times of the value of normal operation when redundancy ratio equals to 10% is drawn. Finally, the correctness of the analysis and control strategies is verified by experiment and simulation.
Variable-speed drives (VSD) can be utilized in fluid handling system diagnosis and monitoring methods. Many of these methods can be implemented without additional sensors, which together with the ubiquity of VSDs makes them cost-efficient. This paper proposes a sensorless VSD-based method for estimating the pressure drop caused by air filter fouling.
In this paper we demonstrate how a statistical model checking approach can be used to check the dynamic performance of the finite set model predictive control algorithm for a standalone 3-level neutral point diode clamped converter. The robustness of the control algorithm under parameter uncertainty is also analyzed. Finite control set model predictive control (FCS-MPC) algorithm has found many applications in power electronics due to the straightforward control design and the possibility to include different control objectives. The control algorithm for 3-level neutral point diode clamped (NPC) converter has to address several objectives to provide optimal reference tracking during load transients. Therefore, looking from the perspective of the implementation, the FCS-MPC algorithm suits the control requirements of NPC converter. However, the problem remains in performing an analytical performance verification of the algorithm to demonstrate its robustness, which is compulsory for any industrial application. In this paper, we present how a statistical model checking approach can be used to solve this problem and also provide valuable data about the algorithm's performance during transients and in the case of parameter uncertainty. A benchmark model is created in Matlab/Simulink to validate the correct system modeling in UPPAAL SMC toolbox.
This paper addresses the capability of the 3.4MW SENVION wind turbine for providing an active power and dynamic voltage control during grid faults by injecting active and reactive currents, both in positive and negative sequence. The proposed control scheme complies with the most cutting-edge requirements of the grid codes, with a totally sequence-independent current control. The on-site performance of the FC NES 3.XM 3400LV2LSWC INGECONW is shown, as well as the effects current injection has on the grid voltage during the fault.
This paper presents the development and validation of a Wind Turbine (WT) harmonic model for harmonic analysis in power systems. For that purpose and based on standard WT generic models, some changes and the implementation of additional structures are proposed to represent the influence of the wind turbine in the frequency domain. The validation of the model is done with a comparison between the results obtained from the WT harmonic model implemented in Matlab/Simulink and an experimental platform. The experimental results are performed on a test bench with a downscale version of the INGECON WIND MV100 commercial converter of Ingeteam manufacturer. The harmonic emission is tested for two modulation strategies, the typical CB-PWM and a new synchronous SHE-PWM based modulation. The results show good agreement between the model and the real converter.
Nowadays, switched reluctance motor drives are one of the most promising alternatives for the elimination of permanent magnets in the electric traction systems, due to their well-known advantages such as simple and rugged construction, high efficiency, speed torque characteristic well adapted to traction needs and despite their drawbacks high torque ripple and high acoustic noise. Unfortunately, nowadays, the lack of commercial controllers intended for switched reluctance motors slows down its use as power traction unit. This paper tries to overcome this barrier proposing a specific controller, understood as the assembly of electronic power converter and control unit, for electric light vehicles. First, the specifications of the controller will be exposed then a comprehensive description of the architecture of the controller and details about the choice of its components will be given. Finally, experimental results will be shown in order to demonstrate its suitability as a SRM controller for light electric vehicles.
This paper focuses on the prevention of partial discharge (PD) at the edge of the nickel coated Cu-ceramic interface of 6.5 kV IGBT substrates due to high electric field effects. A high temperature polyimide has been used to enhance the PD capability. The addition of silane coupling agents to the polyimide has improved the bond strength to metal and ceramic surfaces thereby enhancing the structures PD resistance.
