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Since the photovoltaic power generation, wind power and other distributed power supply are volatile and random, they will affect the stability of the grid frequency. In order to improve the voltage and frequency in micro-grid, the virtual synchronous generator control strategy is proposed for inverter control, which can emulate the behavior of synchronous generator, decrease rate of change of frequency...
In this paper, DC-DC power converter based on Galium Nitride Gate Injection Transistors (GaN GIT) is presented. The use of such power devices allows to increase of switching frequency and to reach high efficiency. Efficiency measurements of power conversion were carried out for two switching frequencies (100 kHz, 200 kHz, 400 kHz).
This paper presents two implementations of finite control set model predictive methods applied to AC/DC converters with an LCL filter. The LCL filter in contrast to L filter offers higher level of harmonics attenuation. However, despite its advantages, LCL filter can cause a strong resonance in grid current. The proposed control strategy, i.e. PCi2uc-3L uses basic advantages of the MPC methods — multivariable...
This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing. The algorithm is based upon independent analysis of post fault characteristic signals at each terminal. These characteristic...
In this paper, a multi-degree open-circuit faults diagnostic algorithm, for improving condition monitoring ability of spacecraft solar cell system, has been proposed. This algorithm combines the output parameter, output voltage, output current and the impedance of solar cell system under low frequency domain. The algorithm can be used to diagnose the degree of faults quantitively and quickly. The...
Dedicated wide band current transformers exist. However, in this paper, an evaluation is made of the characteristics of a current transducer based on a standard available common mode filter inductor. Based on the inductance and resonance frequency, a frequency span of 0.5 Hz up to 50 MHz can be achieved. The performance is possible by the fact that the used amorphous materials have a very high permeability...
Recently main requirements for power conversion system are further downsizing and higher efficiency. To satisfy these requirements, enhanced power density of power modules should be the key to succeed. In this paper, 3.3kV SiC-Hybrid module with High Power next Core package, which can realize enhanced power density, has been described.
The paper examines the work of the microgenerator inverter during two-phase short circuits. It has been shown that the cause of the oscillation is incorrect synchronization of the inverter. It has been demonstrated that the reduction of the oscillations can be achieved by adapting the synchronization signal to the representation of unbalanced system voltages.
Traditionally, active magnetic levitation systems in rotor applications comprise separate motor for torque production, two or more radial active magnetic bearings (AMBs) and one axial AMB. Such an arrangement produces long rotors. Resulting AMB-rotor systems are often supercritical making the levitation control challenging. The centralization of the torque and force producing actuators shortens the...
The paper discusses an issue of the voltage balancing in the intermediate DC circuit of a three-level converter system for a smart grid application. A combination of two methods of the voltage balancing is presented in the paper. The voltages of DC-link capacitors, depending on the operating mode, are controlled by the three-level grid connected AC/DC converter or by the two level DC/DC converter...
To eliminate current harmonics and improve voltage utilization. When traction motor was run in high speed area, a new method is proposed that solve the harmonics component is high and transition which from SPWM to SHEPWM then to six-step mode on the condition of low switch frequency. The method was introduced, principles were analyzed and formulas were derived in this paper. The validity of the proposed...
A Power Hardware in the Loop (FHIL) platform implementation for performing real time simulations of electric systems is proposed. The test bench consists of a FSS'®E real time power flow calculation in combination with a controlled grid emulator. Experimental results are presented to demonstrate the performance of the platform.
For sensorless control at zero or low speed, extending the bandwidth by higher HF signal-injection frequencies is desirable. Therefore, knowledge of the HF machine parameters for the electrical angle calculation is necessary. Conventional methods to determine the HF machine parameters using sinusoidal signals reach their limits using a standard industrial converter. The restricted switching frequency...
This paper presents a concept for a compact high voltage generator based on a highly integrated power chain switching at frequencies above 500 kHz. The high frequency operation in combination with the high integration approach enable a reduction of volume and weight of HY-generators used in industrial or medical applications.
A novel topology for LED drivers is proposed. The system does not require rectifier input stage nor storage DC bus capacitor. The topology is described and studied by simulation. Experimental results on an AC LED demonstrator using GaN transistors validate the proposed circuit.
In this paper, we clarify the problem of power supply characteristics when the secondary coil of the PS resonance type DWPT system, and have proposed a technology that enables high efficiency and stable power supply at the time of moving the secondary coil and revealed its effectiveness.
Medium voltage 10 kV Silicon Carbide MOSFETs, introduce challenges regarding converter design. Very high rate of voltage change and capacitive couplings to for example cooling systems cause increased electromagnetic interference. The aim of this paper is to accurately model the capacitive coupling to a heat sink and experimentally validate the model. An analytic model of the heat sink is developed...
Lithium-ion battery second life usage might be an interesting solution for certain applications and it can bring not only environmental benefits but also e.g. lower electric vehicles or hybrid electric vehicles total cost of ownership. However, the electrical performance and performance degradation of the battery systems in the second life application are still unknown what brings significant economic...
There are problems with insulation failures in high-voltage transformers due to fast transient voltages. Within novel Solid-State Transformers (SST) this problem exists constitutionally because of the SSTs rectangular working voltages. Experiments and simulations have been performed to get accurate understanding of the phenomena. The results and theories are discussed in this paper.
Energy saving is arguably the most important factor in issues regarding energy and carbon emission. For electric vehicles in particular, saving energy extends the driving range. This can be achieved with a highly efficient variable-speed drive that can cover a wide speed range, and changing the number of poles is one way of realizing such a drive. In addition, electric vehicles must be fault tolerant...
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