Search

Testing the performance of a battery management system (BMS) is extensive and crucial due to its importance for the overall battery safety and performance. In this paper, a hardware-in-the-loop (HiL) test bench is presented for rapid prototyping, testing and evaluation of BMS algorithms in real-time. The system is designed to work with real cell packs without any additional electronics or casing. This approach avoids the high cost and effort of building a full battery system and therefore simplifies algorithm testing on different cell types and cell pack topologies. An extended Kalman Filter based state-of-charge-algorithm is developed and compiled in C-Code in MATLAB/Simulink to run on a digital signal processor (DSP) in real-time. The capabilities and advantages of the setup are shown with experimental HiL tests of the developed BMS algorithm in comparison to software-in-the-loop (SiL) tests.

A highly robust and dynamic control of the MMC grid currents is necessary to ensure grid stability. Based on a state space modelling of the MMC, a real time capable indirect modelbased control is presented. Measurements with a laboratory setup show the reliability even under disturbed grid conditions.

This paper presents a highly customizable 120kVA Power-Hardware-in-the-Loop test bench. The output stage consist of two identical Parallel Hybrid Converters each with a 17-level output voltage and an effective switching frequency of 1MHz. The Parallel Hybrid Converters can provide 3-phase AC or bipolar DC as output voltage. Thus, one 6-AC, 3-AC or DC system or two systems with 2x3-AC, 1x3-AC and 1xDC or 2xDC can be emulated.

This paper presents a comparison of different AC to AC Modular Multilevel Converter (MMC) concepts for selected distributed energy generation applications. The MMC topology is a highly suited and investigated candidate for high voltage transmission systems ([1]–[3]). The applications selected for this paper are an medium voltage AC to AC grid coupling system and an medium voltage converter based wind generator connection to the AC grid. The comparison is done for different circuit configurations using the most attractive cell topologies. The power capability of the different circuit and cell combinations is shown based on a common power semiconductor and energy storage hardware. Real device limitations including not only semiconductor losses but also real cell capacitor AC voltage and current limits are taken into account. Furthermore realistic application data with respect to AC voltage range, power factor and current capabilities are included. This allows a realistic and application related comparison of the required power electronic hardware based on real device data over the entire P/Q range. Finally, the hardware limitations become evident which allows the evaluation of appropriate hardware changes to adapt the required performance.

This paper presents a new control strategy for Modular Multilevel Matrix converters where the output frequency is higher then the input frequency. In operating points when ��$_{out}$ $ \geq \ $ ��$_{in}$ the energy pulsation in the converter cells are dominated by the second harmonic of the input frequency. These energy pulsations can be identified and compensated by inducing additional currents. The results are verified by simulation for a laboratory scaled prototype of the Modular Multilevel Matrix Converter.

A continuous-time bandpass delta-sigma modulator (CT BDSM) is designed and fabricated in a SiGe bipolar transistor technology with a transit frequency of 200 GHz. The modulator can be tuned in its center frequency from 1.55 GHz up to 2.45 GHz for mobile base station applications. To drive a GaN high power amplifier a driver amplifier is presented using a complementary bipolar transistor technology.

The signal intensity and contrast of NMR images depend both on measurement parameters and on tissue parameters. The most essential measurement parameters are the repetition time TR and the spin echo time TE. The effect of the echo time on the image contrast is demonstrated by the multi echo images shown in Fig. 3.1. The significant change in image contrast with increasing echo time is clearly demonstrated. The tissue specific parameters are the relaxation times T1 and T2, the proton density P and the diffusion coefficient D. Furthermore, the signal intensity in vessels is also fundamentally influenced by the flow velocity of the blood (see below). By applying chemical shift imaging methods, it is also possible to generate separate images of fat, water and magnetic susceptibility.

Magnetic Resonance Imaging (MRI) allows the display of anatomical heart structures at a temporal resolution in the magnitude of 20 ms. Several pictures may be taken in one scanning process or with consecutive measurements at varying trigger delay times. By comparison of the positions of certain myocardial regions at certain times, the assessment of ventricular motion in all heart phases is possible. The specificity for the identification of any region of the myocardium in the three-dimensional space is high. If the signal phases rather than the amplitudes are reconstructed into an image, motion effects at any trigger delay can be visualized directly on the basis of single scans and may be further analyzed.