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Inverter disturbance has been widely discussed to improve the performance of AC motor control, with the very high nonlinearity and uncertainty of power electronic devices, it is still very difficult to be estimated and compensated accurately; therefore, the performances of most AC motor observers are affected by the inaccurate terminal voltage estimation. In this paper, the principle of PWM (pulse...
This paper presents Model predictive control technique for the high efficiency with reduced switches stresses T-type three-level Neutral Point Clamped (NPC) inverter for Photovoltaic (PV) applications. T-type three-level NPC inverter is a combination of the NPC and T-Type inverters. As it is a combination of T-type and NPC it has the same features of NPC such as breakdown voltage of the switching...
This paper concerns AC feeding system and the power supply in the dead section for auxiliary equipment. We developed the uninterruptible method using regenerative power of traction circuits through main transformer. To verify the proposed method, we executed the running tests using high power electrical locomotive. We show these outlines.
Ring oscillators are very popular process monitors due to its easy implementation and high sensitivity to process parameters. This paper presents a technique to accurately estimate the absolute threshold voltage Vth of device under test (DUT) using a reconfigurable ring oscillator (RO). Conventional techniques exploit NMOS-pass transistor based RO to estimate the Vth. However, the RO frequency includes...
In this paper, we consider the construction of True Random Numbers Generators (TRNGs) using variations in power supplies. We demonstrate that power supply line outputs do not have a constant voltage and the variations in voltage follow a normal distribution. These variations can be used to create truly random bits that demonstrates a high entropy rate based on the results obtained from the NIST Statistical...
Islanding is a special type of open circuit fault where the distributed resource continues to feed local loads during loss of mains situation. This paper develops a technique to detect islanding in a six bus power system. The input to the technique is dependent on synchrophasor measurement. The decision made in the technique is based on IEC62116 standards and predefined threshold and of current phasors...
This paper presents a control approach for improving transient behavior of an autonomous inverter-based microgrid employing secondary controller. A feed-forward loop is utilized to enhance the characteristics of active and reactive power responses. This stage is implemented in power controller section. It can be proved that this approach has the capability of improving the stability of microgrid using...
Grid tied inverters and associated control techniques have gained importance in the domain of distributed generation. Different methods of control have been compared in literature depending upon the ability to meet THD limits, damping offered to resonant oscillations and stable operation. Multiple loop methods compared to their single-loop counterparts have proved to be highly effective for meeting...
In recent years, there has been a rapid increase in the number of photovoltaic (PV) three phase inverter systems being to grid connected. Keeping the highly quality waveform and low harmonic distortion of the current waveform during abnormal condition is one of the most challenging. To achieve this target, a current control technique is carefully considered. This paper present a simple method to compensate...
Realization of high power conversion system utilizing parallel connected power converters rated at much smaller power levels due to limitations in switching device voltage and current ratings would be highly desirable. Therefore, modular configured converters are imminent in high power industrial applications due to their numerous benefits over singular high capacity converter or inverter. They can...
The concept of transformerless inverters has become a future trend for single phase photovoltaic grid — tied systems. The major factor to be considered while employing transformerless inverters in such applications is the leakage currents. The lack of transformers in inverters, implemented between PV panel and grid results in a galvanic connection and thus there arises problems due to leakage currents...
By utilizing an inherently symmetrical differential structure, several boost DC/DC converters can be used to construct a multi input DC/DC or DC/AC converter. The use of integral state feedback based pole placement control strategy has been reported in the literature to control this type of converter. However, this control method is based on the small signal model of the circuit and highly dependent...
Purpose of this paper is the study by simulation of a fault tolerant control with pulse large modulation (PWM) AC-DC-AC converter supplying a three-phase rotor field oriented induction motor. The back to back converter, is supplied with three-phase network and composed of a PWM rectifier and a voltage source inverter. Fault tolerant topology of AC-DC-AC converter that with redundancy have been studied...
AC-DC interaction is a common phenomenon whenever HVDC network is weakly connected to AC system. Sometime it leads to severe voltage stability problems on AC bus depending on AC system capability and available amount of VAr compensation. For instance, there are many examples of offshore wind farms connected to onshore grids through HVDC links. When onshore grids may be stressed during contingencies,...
Photovoltaic systems (PVS) based MicroGrid (MG) should be able to operate at the maximum power point (MPP) in order to extract the maximum available power during atmospheric conditions changes. In addition to this, the PVSs should be able also to operate below the MPP in order to participate to the MG regulation such as grid frequency stabilization, voltage profile control and grid management support...
An on-chip, low power, and area efficient charge-pump (CP) that generates a multiple of the supply voltage (VDD) in a single clock cycle is presented. The proposed CP utilizes parallel cross-connected CP units, which are implemented using MIM (metal-insulator-metal) capacitors. In the target application, i.e., a sub-threshold SRAM, the capacitors are accommodated on top of the memory banks to remove...
This paper introduces a predictive voltage controller for multilevel inverter used in Dynamic Voltage Restorer, which is able to protect a sensitive load against grid voltage sags dynamically. The compensated voltages are obtained by using Phase-Lock Loop to detect the phase and the magnitude of the grid voltage then compare to the load reference voltage. A three-phase NPC inverter with output LC...
This paper presents an implementation technique of a high resolution Unipolar Pulse Width Modulator (UPWM) for power inverter applications. Unipolar switched inverter has the advantage of a higher efficiency and lower harmonic distortion. The technique was tested in a 2kW inverter with a typical LC filter and it was achieved a Total Harmonic Distortion below 2%. Simulations and experimental results...
To improve the design and test of main circuit of aerospace power inverter, a dynamic testing technique is proposed in this paper. Through high speed signal acquisition and isolation, monitoring and evaluating the voltages and currents changing process of main circuit, the design parameters can be optimized based on the testing results which can improve the reliability and electromagnetic compatibility...
This article deals with the simulation of the power converter with voltage-source inverter and sine-filter. The repetitive control system was designed. The existing power converter has a control system which makes Fourier transform of the output voltage to inject these harmonics with opposite phase. The new proposed system based on repetitive controller which is much simpler and with smaller CPU load...
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