Performance evaluation of different configurations of system with DSTATCOM using proposed Icos⁡ϕ technique

The proposed Icos⁡ϕ control technique has been applied for power quality improvement using different configurations of system with distribution static compensator (DSTATCOM). Modeling, design and control of DSTATCOM are analysed in detial. Three phase reference current are extracted with this technique. The proposed technique has been used for power factor enhancement, voltage regulation, harmonic suppression and load balancing under dynamic condition with non-linear load. The proposed control is very effective for three different configurations of system with DSTATCOM for power quality improvement. Results for each configuration of system with DSTATCOM are simulated using MATLAB/Simulink sim power tool box. For teaching the power quality course, these can also be helpful.

Harmonic suppression compensation of photovoltaic generation using cascaded active power filter

The wide spectrum of electromagnetism that explains current and voltage at specific time and location in a power system is referred to as power quality. Alternative energies are becoming more popular due to concerns about power quality, safety, and the environment, as well as commercial incentives. Moreover, photovoltaic (PV) energy is one of the most well-known renewable resources since it is free to gather, unlimited, and considerably cleaner. Active power filter (APF) is an effective means to dynamically suppress harmonics and solve power quality problems caused by the DC side voltage fluctuation. Therefore, this paper describes a substantial advancement in the harmonic suppression compensation algorithm, as well as the cascaded active power filter. Also, this paper focuses on compensating the error of photovoltaic grid-connected generation based on optimized H-bridge cascaded APF. The details of the working principle and topological structure of the APF used as the compensation device are analyzed. The H-bridge cascaded APF is optimized using the segmented variable step-length conductance increment (SVSLCI) algorithm. The overall cascaded APF control strategy is designed and simulated using MatLab/Simulink environment. By the simulation results comparing the existing traction network power quality control measures, before and after compensation, the effectiveness of the proposed control strategy is verified. The proposed controller strengthens the compensation of specific odd harmonics to improve the system work models and criteria to improve power quality. Moreover, the proposed algorithm showed positive significance for optimizing the quality of photovoltaic grid-connected power, reducing the current harmonic, and improving the equipment utilization of photovoltaic inverters.

Research of Power Distribution System Dynamic Simulation Based on Grid’s Harmonic Current

Harmonic current in power grid will cause extra power consumption of electrical equipment and affect the stable operation of power grid. Based on the dynamic model experiment system of 10kV distribution network, a working platform for parallel operation of charging pile was built, which studied the harmonic current components and analyzed the simulation waveform. The results show that with the increase of number of charging piles, the content of harmonic current will decrease correspondingly, the main components are low frequency odd harmonics; When 16 charging piles are connected in parallel, three harmonics are the main components; the waveform of the simulation calculation curve and the actual measurement curve are basically consistent, and the current amplitude of each frequency harmonic wave is basically the same , so it is proved that the dynamic model test platform is reasonable and feasible to test grid’s harmonic current. The dynamic model can provide technical support for harmonic suppression research.

Design and Analysis of a Wide Stopband Microstrip Dual-band Bandpass Filter

A novel configuration of a dual-band bandpass filter (BPF) working as a harmonic attenuator is introduced and fabricated. The proposed filter operates at 3 GHz, for UHF and SHF applications, and 6.3 GHz, for wireless applications. The presented layout has a symmetric structure, which consists of coupled resonators. The designing of the proposed resonator is performed by introducing a new LC equivalent model of coupled lines. To verify the LC model of the coupled lines, the lumped elements are calculated. The introduced filter has a wide stopband up to 85 GHz with 28th harmonic suppression, for the first channel, and 13th harmonic suppression, for the second channel. The harmonics are attenuated using a novel structure. Also, the proposed BPF has a compact size of 0.056 λg2. Having several transmission zeros (TZs) that improve the performance of the presented BPF is another feature. The proposed dual-band BPF is fabricated and measured to verify the design method, where the measurement results confirm the simulations.

Low-Phase-Noise Oscillator Using a High-QL Resonator with Split-Ring Structure and Open-Loaded T-Type Stub for a Tumor-Location-Tracking Sensor

Sensors in the medical field to detect specific tissues, such as radars, must provide accurate signals from frequency generators. In order to supply an accurate frequency signal, the oscillator must have a low phase noise. Therefore, the resonator used in the oscillator must provide a high QL. Therefore, in this paper, we have proposed a low-phase-noise X-band oscillator that used a resonator with a high value of QL as a sensor for tissue-locating applications. The resonator had a split-ring structure and consisted of an open-loaded, T-type stub with a high-QL; such high-QL levels were enabled by controlling the length of the open-circuit in the T-type stub. This led to the generation of only low-phase noise in the proposed oscillator. Experimental results showed that, at an operating frequency of 10.08 GHz, the output power was 18.66 dBm, the second harmonic suppression was −34.40 dBc, and the phase noise was −138.13 dBc/Hz at an offset of 100 kHz. This proposed oscillator can be used as a sensor to detect the location of tissues during laparoscopic surgery.

Composite Control Strategy of Output Current of LCL Photovoltaic Grid-Connected Inverter

In order to further optimize the output current harmonic suppression effect of photovoltaic grid-connected inverters, a composite control strategy of LCL type photovoltaic grid-connected inverter output current is proposed. This strategy combines proportional complex integral (PCI) control and repetitive control (RC) in parallel, draws a composite control block diagram, introduces a transfer function, and designs PCI and RC control parameters. Prove that the compound control can reduce current harmonics, achieved the purpose of reducing the steady-state error of the fundamental frequency. And adopts a new PCI composite control strategy, which helps to save the cost of the control system. By building the MATLAB/Simulink simulation platform and establishing the PCI+RC composite control model of LCL photovoltaic grid-connected inverter, the comparison of the simulation results shows that compared with the PI+RC control strategy, the total harmonic distortion rate of the grid-connected current is reduced by 25.77. %, significantly improving the quality of grid-connected current.