scholarly journals A Power Calculation Algorithm for Single-Phase Droop-Operated-Inverters Considering Linear and Nonlinear Loads HIL-Assessed

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1366 ◽  
Author(s):  
Jorge El Mariachet ◽  
Jose Matas ◽  
Helena Martín ◽  
Mingshen Li ◽  
Yajuan Guan ◽  
...  
Keyword(s):  
Single Phase ◽  
System Stability ◽  
Power Calculation ◽  
Parallel Operation ◽  
Calculation Algorithm ◽  
Nonlinear Loads ◽  
Nonlinear Load ◽  
Low Pass ◽  
Dynamic Velocity ◽  
The Stability

The active and reactive powers, P and Q, are crucial variables in the parallel operation of single-phase inverters using the droop method, introducing proportional droops in the inverter output frequency and voltage amplitude references. P and Q, or P-Q, are calculated as the product of the inverter output voltage and its orthogonal version with the output current, respectively. However, when sharing nonlinear loads these powers, Pav and Qav, should be averaged by low-pass filters (LPFs) with a very low cut-off frequency to avoid the high distortion induced by these loads. This forces the droop method to operate at a very low dynamic velocity and degrades the system stability. Then, different solutions have been proposed in literature to increase the system velocity, but only considering linear loads. Therefore, this work presents a method to calculate Pav and Qav using second-order generalized integrators (SOGI) to face this problem with nonlinear loads. A double SOGI (DSOGI) approach is applied to filter the nonlinear load current and provide its fundamental component to the inverter, leading to a faster dynamic velocity of the droop-based load sharing capability and improving the stability. The proposed method is shown to be faster than others in the literature when considering nonlinear loads, while smoothly driving the system with low distortion levels. Simulations, hardware-in-loop (HIL) and experimental results are provided to validate this proposal.

scholarly journals HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1643
Author(s):  
Jorge El Mariachet ◽  
Yajuan Guan ◽  
Jose Matas ◽  
Helena Martín ◽  
Mingshen Li ◽  
...  
Keyword(s):  
Steady State ◽  
Single Phase ◽  
Reactive Power ◽  
Dynamic Performance ◽  
Active Power ◽  
Voltage Source ◽  
Power Calculation ◽  
Calculation Algorithm ◽  
Nonlinear Loads ◽  
Voltage Source Inverters

The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal.

scholarly journals Power Calculation Algorithm for Single-Phase Droop-Operated Inverters Considering Nonlinear Loads and unsing n-Order SOGI Filtering

2018 ◽  
Vol 1 ◽  
pp. 710-715 ◽  
Author(s):  
J. El Mariachet ◽  
◽  
J. Matas ◽  
J. de la Hoz ◽  
Y. Al-Turki ◽  
...  
Keyword(s):  
Single Phase ◽  
Power Calculation ◽  
Calculation Algorithm ◽  
Nonlinear Loads

The Effect of Digital Process of Single-Phase Photovoltaic Grid Connected Inverter

2014 ◽  
Vol 1070-1072 ◽  
pp. 60-63
Author(s):  
Hong Tao Shan ◽  
Bin Zhou
Keyword(s):  
Digital Control ◽  
Single Phase ◽  
Zero Order ◽  
System Stability ◽  
Stability Range ◽  
Delay Control ◽  
One Step ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Sample Time

Digital control possesses evident advantages and has become a mainstream control of photovoltaic grid connected inverter.The mathematical model and parameter setting of the single phase photovoltaic grid connected inverter with L filter was introduced in the paper.It was analysed on the effect on system stability of digital process from the two aspects which were the zero-order-hold and one-step-delay control. The bode diagram was verified the theoretical analysis on system stability.The conclusions were made that the introduction of digital control reduces the critical stable gain of photovoltaic grid connected inverter system,system stability is varied with sample time, the parameters of L can affect the system stability range,zero-order-hold reduces the stability range and limits the performance improved of digital control system,one-step-delay control on photovoltaic grid connected inverter reduces again the stability range on the basis of the zero-order-hold control.

scholarly journals Power Calculation Algorithm for Single-Phase

2018 ◽  
Vol 1 (16) ◽  
pp. 19-24
Author(s):  
J. El Mariachet ◽  
◽  
J. Matas ◽  
Helena Martín ◽  
Abdullah Abusorrah
Keyword(s):  
Single Phase ◽  
Power Calculation ◽  
Calculation Algorithm

scholarly journals Determination of Inactive Powers in a Single-Phase AC Network

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4814
Author(s):  
Nickolay I. Shchurov ◽  
Sergey V. Myatezh ◽  
Boris V. Malozyomov ◽  
Alexander A. Shtang ◽  
Nikita V. Martyushev ◽  
...  
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Supply Voltage ◽  
Time Base ◽  
Nonlinear Loads ◽  
Nonlinear Load ◽  
Voltage Curve ◽  
Current Curve ◽  
Definition Of

Based on the development of the theory of reactive power and distortion power, starting with the works of Fryze and Budeanu, it has been found that the contradictions in the definition of the components of inactive powers are caused by errors in the introduced intermediate concepts and corresponding calculations when switching to nonlinear and non-sinusoidal AC circuits. The materials of the works of modern researchers and the numerical calculations carried out made it possible to trace the differences between reactive power and distortion power, to confirm the orthogonality properties of the active, reactive power, and distortion power components. The paper defines the conditions for achieving a power balance in an AC network with nonlinear loads, compiled and tested criteria leading to the absence of distortion power in a single-phase AC network. Using the time base of the projection of the generalized vectors in vector diagrams, it is shown that compliance with the criteria for the absence of distortion power does not determine the mutual similarity of the voltage curve with the current curve for a nonlinear load. It has been found that the well-known term “distortion power” has an unfortunate wording, since this power, although it characterizes the interaction of harmonics of currents and voltages with different ordinal numbers, is not determined by the visual similarity or the degree of distortion of the load current waveforms relative to the supply voltage curve.

scholarly journals Compressional of LLCL Filter and LCL Filter using Single-Phase Multi-Cell AC-DC Converter

2019 ◽  
Vol 8 (6S4) ◽  
pp. 516-521
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
System Stability ◽  
Power Electronic ◽  
Optimization Scheme ◽  
Pulse Modulation ◽  
Passive Components ◽  
Filter Structure ◽  
The Stability ◽  
Electronic Switches

This paper elucidates a multi cell rectifier for AC to DC for single-phase energy transformation which is obtained by exclusive converter circuits to generate high frequency using the passive components for alternating to direct current. The anticipated method hires an easy structure based on concept of pulse modulation. An effective optimization scheme is exploited to enhance the filter constraints. A converter using power electronic switches will generate the harmonics. Harmonics will reduce the system stability. The harmonics reduced by using LLCL filter structure will enhance the stability of the power system network. The comparsion of LCL and LLCL filter is made with the help of THD analysis.

A Fast Instantaneous Power Calculation Algorithm for Single-Phase Rectifiers Based on Arbitrary Phase-Delay Method

2019 ◽  
Vol 55 (4) ◽  
pp. 3935-3945
Author(s):  
Chengxiang Zhang ◽  
Siru Yu ◽  
Keteng Jiang ◽  
Xinglai Ge ◽  
Junpeng Ma
Keyword(s):  
Single Phase ◽  
Phase Delay ◽  
Power Calculation ◽  
Calculation Algorithm ◽  
Instantaneous Power ◽  
Arbitrary Phase

scholarly journals Dual Two-Level Voltage Source Inverter Virtual Inertia Emulation: A Comparative Study

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1160
Author(s):  
Mohammad Ali Dashtaki ◽  
Hamed Nafisi ◽  
Amir Khorsandi ◽  
Mojgan Hojabri ◽  
Edris Pouresmaeil
Keyword(s):  
Harmonic Distortion ◽  
Synchronous Generator ◽  
Voltage Source ◽  
Small Signal ◽  
Voltage Source Inverter ◽  
Nonlinear Loads ◽  
Virtual Inertia ◽  
The Stability ◽  
Stability Enhancement ◽  
Oscillation Damping

In this paper, the virtual synchronous generator (VSG) concept is utilized in the controller of the grid-connected dual two-level voltage source inverter (DTL VSI). First, the topology of the VSG and the DTL VSI are presented. Then, the state-space equations of the DTL VSI and the grid-connected two-level voltage source inverter (TL VSI), regarding the presence of the phase-locked loop (PLL) and the VSG, are given. Next, the small-signal modeling of the DTL VSI and the TL VSI is realized. Eventually, the stability enhancement in the DTL VSI compared with the TL VSI is demonstrated. In the TL VSI, large values of virtual inertia could result in oscillations in the power system. However, the ability of the DTL VSI in damping oscillations is deduced. Furthermore, in the presence of nonlinear loads, the potentiality of the DTL VSI in reducing grid current Total Harmonic Distortion (THD) is evaluated. Finally, by using a proper reference current command signal, the abilities of the DTL VSI and the TL VSI in supplying nonlinear loads and providing virtual inertia are assessed simultaneously. The simulation results prove the advantages of the DTL VSI compared with the TL VSI in virtual inertia emulation and oscillation damping, which are realized by small-signal analysis.

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