scholarly journals Controlled Energy Flow in Z-Source Inverters

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7272
Author(s):  
Zbigniew Rymarski ◽  
Krzysztof Bernacki ◽  
Łukasz Dyga
Keyword(s):  
Energy Flow ◽  
Output Voltage ◽  
Photovoltaic Cell ◽  
Voltage Source ◽  
Output Frequency ◽  
Maximum Power Point ◽  
Voltage Source Inverters ◽  
Voltage Output ◽  
Voltage Drops ◽  
Power Point

This paper proposes a method to reduce the output voltage distortions in voltage source inverters (VSI) working with impedance networks. The three main reasons for the voltage distortions include a discontinuous current in the coils of the impedance network, the double output frequency harmonics in the VSI’s voltage output caused by insufficient capacitance in the impedance network, and voltage drops on the bridge switches during the shoot-through time. The first of these distortions can be reduced by increasing the current of the impedance network when the output VSI current is low. This method requires storing energy in the battery connected to the DC link of the VSI during the “non-shoot through” time. Furthermore, this solution can also be used when the Z-source inverter works with a photovoltaic cell to help it attain a maximum power point. The Z-source inverter is essentially a voltage source inverter with the Z-source in the input. In this paper, the theory behind basic impedance networks of Z-source and quasi-Z-source (qZ-source) is investigated where simulations of the presented solutions and experimental verification of the results are also presented.

A Structural-Algorithmic and Parametric Synthesis of Single-Phase Voltage Source Inverters for Increased Power Capacity

2021 ◽  
Vol 2 (2) ◽  
pp. 44-53
Author(s):  
GENNADY S. MYTSYK ◽  
◽  
ZAW HTET HEIN ◽  
Keyword(s):  
Energy Flow ◽  
Output Voltage ◽  
Power Plants ◽  
Single Phase ◽  
Voltage Source ◽  
Phase Voltage ◽  
Power Capacity ◽  
Voltage Source Inverters ◽  
Solar Power Plants ◽  
Output Filter

The recent interest of developers of new technology in studying a structural and algorithmic synthesis (SAS) of voltage source inverters (VSI) for solar power plants (SPP) is stemming from a growing need to solve problems in connection with the revealed new possibilities of converting energy flow (from DC to AC) with better energy efficiency by reducing the depth of its pulse modulation. This problem is solved by using more rational structural and algorithmic solutions. It is shown that for SPPs for a capacity of about 1 MW and more, it is more expedient to construct inverters based on the energy flow multichannel conversion principle. Given a limited power capacity of the transistor components, the application of this principle allows the problem to be solved in fact without using an output filter. The output voltage waveform is shaped using the energy flow pulse-amplitude modulation (PAM), and its M parts are summed in the output circuit by out using M winding transfilters (M-TF). The proposed method for carrying out combined SAS of single-phase voltage source inverters with multichannel conversion is considered, which consists in using an N-level single-phase VSI (N-SPVSI) in each of the M channels with the voltage levels optimized in terms of the minimum total harmonic distortion (THD). The resulting voltage of this class of single-phase inverters, designated as MxN-SPVSI, is formed by the corresponding phase shift of the channel voltages followed by summing the channel currents by M-TF. It is shown that the resulting output voltage levels are also close to their values optimized with respect to the minimum of the THD indicator. The results from a comparative analysis of two options — a single-channel 8-level inverter and a four-channel 8-level inverter are given. For the second option, only one intermediate voltage tap in the solar battery is required (instead of seven taps in the first option) along with modern transistor components that are available for practical implementation. In both options, the THD value less than 5% is obtained with almost no need of using an output filter. The presented results provide a certain information and methodological support for system designing of single-phase voltage source inverters as applied to the specific features of solar power plants. Three-phase inverters can be built on the basis of three single-phase inverters with galvanic isolation of the power sources for each phase.

scholarly journals Predictive Control with Current-Based Maximum Power Point-Tracking for On-Grid Photovoltaic Applications

2021 ◽  
Vol 13 (6) ◽  
pp. 3037
Author(s):  
Carlos Muñoz ◽  
Marco Rivera ◽  
Ariel Villalón ◽  
Carlos R. Baier ◽  
Javier Muñoz ◽  
...  
Keyword(s):  
Predictive Control ◽  
Renewable Energy Sources ◽  
Maximum Power Point Tracking ◽  
Maximum Power ◽  
Voltage Source ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Pi Controllers ◽  
Power Point

The high increase of renewable energy sources and the increment of distributed generation in the electrical grid has made them complex and of variable parameters, causing potential stability problems to the PI controllers. In this document, a control strategy for power injection to the electrical system from photovoltaic plants through a voltage source inverter two-level-type (VSI-2L) converter is proposed. The algorithm combines a current-based maximum power point-tracking (Current-Based MPPT) with model predictive control (MPC) strategy, allowing avoidance of the use of PI controllers and lowering of the dependence of high-capacitive value condensers. The sections of this paper describe the parts of the system, control algorithms, and simulated and experimental results that allow observation of the behavior of the proposed strategy.

Daily Constant PV Output Power Supplying AC pumps using Batteries

2016 ◽  
Vol 2 (2) ◽  
pp. 275
Author(s):  
Mohamed Mahmoud Ismail
Keyword(s):  
Output Power ◽  
Boost Converter ◽  
Operating Conditions ◽  
Voltage Source ◽  
Maximum Power Point ◽  
Pv Array ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Three Phase ◽  
Power Point

This paper presents 200 KW three phase standalone photovoltaic systems supplying pumping station consist of four pumps 40 KW rating. The system utilizes a two stage energy conversion power conditioning unit topology composed of a DC-DC boost converter and three level-three phase voltage source inverter (VSI). The Boost converter in this paper is designed to operate in continuous mode and controlled for maximum power point tracking (MPPT). The fluctuating output power of the PV array system during the day is the commonly problem in the power system.  In this paper a nickel-Cadmium battery will be used to maintain the output power generated from the PV array supplying the pumps to be constant all the day under different operating conditions. The system is modeled and studied using MATLAB/Simulink

scholarly journals Analysis Performance of Grid Tie Photovoltaic Type Polycrystalline Using Solar Irradiance Simulation

2019 ◽  
Vol 125 ◽  
pp. 14013
Author(s):  
Kurniawan Galih Putra Pratama ◽  
Hermawan Hermawan ◽  
Trias Andromeda
Keyword(s):  
Photovoltaic Performance ◽  
Electrical Energy ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Total Irradiance ◽  
Power Point ◽  
Tropical Climates

Indonesia is a country consisting of several islands some of which are still not covered by electricity. It is this source of PV that can be used to meet the needs of people who are not yet affordable with PLN electricity. Basically, PV includes the generation of new renewable energy types. This new form of energy comes from sunlight. Using semiconductor materials can convert energy from sunlight to electrical energy. Because in Indonesia this includes tropical climates located on the equator line, making Indonesia has a very high intensity of light. Several factors affect electrical energy, namely the extent of PV to be used, the total irradiance received by PV, the decrease in performance due to weather and cleanliness of the PV used such as snow and oiliness. In this study explained the Analysis of Irradian-based Grid Tie photovoltaic performance with Polycrystalline PV types. Taking irradian data using a Solar Power Meter, irradiance and temperature data at a certain time will use the Incremental Maximum Power Point Tracking (MPPT) method, DC-DC boost converter, inverter, voltage source converter (VSC) using algorithm and equipment controls connected to network. This research is simulated using Matlab with the Simulink program.

A New Engineering Model of Solar Array and MPPT Control

2011 ◽  
Vol 383-390 ◽  
pp. 591-597 ◽  
Author(s):  
Xiao Lei Wang ◽  
Liang Yang ◽  
Pan Yan
Keyword(s):  
Light Intensity ◽  
Output Voltage ◽  
Maximum Power ◽  
Solar Array ◽  
Reference Standard ◽  
Engineering Model ◽  
Maximum Power Point ◽  
Incremental Conductance ◽  
Power Point ◽  
Pursuit Gain

An engineering model of solar array can reflect the real-time output voltage and current, the maximum power point voltage, the maximum power point current and the maximum power point in any light intensity and any temperature of solar arrary. A simulation model is established in Matlab/Simulink and proved the engineering model correctly and reliability. Using the method of Perturbation and Observation (P&O) and Incremental Conductance (INC) track the maximum power point of a solar array under the reference standard of these output elements, and found out the pursuit gain around the reference standard oscillation and further to validate the model's reliability.

scholarly journals A Novel Maximum Power Point Tracking Strategy Based on Enhanced Real-Time Adaptive Step-Size Modified Control for Photovoltaic Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Junfeng Zhou ◽  
Yubo Zhang ◽  
Shuxiao Zhang ◽  
Yuanjun Guo ◽  
Zhile Yang ◽  
...  
Keyword(s):  
Solar Energy ◽  
Real Time ◽  
Output Voltage ◽  
Maximum Power Point Tracking ◽  
External Environment ◽  
Maximum Power ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point

With the development of society, the demand for energy keeps increasing. Solar energy has received widespread concern for its renewable and environmentally friendly advantages. As one of the most efficient solar energy devices, the output power of photovoltaic (PV) cells is easily affected by the external environment. In order to solve the problem of the maximum power output of PV cells, this paper proposed a maximum power point tracking (MPPT) method. Based on the online particle swarm optimization (PSO) variable step length algorithm, the pulse width modulation (PWM) control module parameters are set according to the parameters of the PV cells’ output voltage. By dynamically adjusting the output voltage step of the PV cells online, the output of the PV cells is stabilized near the maximum power point (MPP). The simulation results concluded that the method and model could accurately adjust the output voltage according to the external environment changes in real time and reduce the voltage fluctuation at the MPP, providing a new idea to solve the problem of MPPT of PV cells.

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