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# Inverters - Science topic

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Questions related to Inverters

I am evaluting fault in one of my project..but got stuck whether inverters do have reactances or not..if so ( my inverter has an ac capacity of 40kVA and 400 volt)..from this i calculated impedance V^2/P considering unity PF. Is it correct way to find the inverter impedance??. And to obtain PU reactance should i divide by its own base impedance and later change to common base.... OR only divide the obtained impedance by common base impedance????

Looking for answer eagerly..

I am using spwm and i am not using a low pass filter at the output, so my output consists of multiple harmonics. I am thinking of reducing the voltage to 115V rms(of the complete output not just the fundamental component) by reducing the duty cycle of the pulses. I am able to achieve voltage close to 115V rms in this way. But everyone else is suggesting to use a dc-dc converter first to reduce the input dc voltage and then feed it to the inverter. Why my solution is not good and is it compulsory to use a dc-dc converter first in this situation?

I'm designing a multilevel inverter using a cascade of two full bridge inverters and when simulating my nonideal model with a dead time seen but switches on my inverter legs do not switch as required with the dead time Id like to know if there is some explanation to what I am experiencing I'm going to attach images of the one leg of my inverter to show the switching sequence Vds_3b and Vds_3A (drain to source of MOSFET) , 3A and 3B (gating signals) Vgs_3A and Vgs_3B (gate to source)

Dear All,

I am working on hysteresis current controller with the inputs are the reference sinusoidal currents for the three phases and the actual three phase currents. the output of the controller is the gate signal for inverter. when I change the switch on and switch off values in relay block parameters in Simulink, there was no change in the controller performance and gate signals!!! and this against the logic expectations of the change in switching pattern of inverter and then the controller performance. Does anyone help me to know the reasons for this issue and how to solve.

I am grateful in advance.

I would like to determine the performance of an installed PV power plant. What is the way foward to do that?

I have measured values of each secondes, minutes of the plant.(batt, PV,Load,weather,ect)

Thanks

I try to regulate in a single phase inverter with different loads, so I get the result that attached, but my question is there any way by changing a PWM technique or by using another method to get pure current signal or can reduce or eliminate the DC component from it..... With great thanks

We are working on a three phase grid tied inverter(10kW, 415V line, 16A) according to selected switching frequency (50kHz), the calculated inductance and capacitance value for LCL filter to be 340uH, 10uF, 34uH. we tested in hardware this removes the switching frequency ripples. But to link with power grid, whether this inductance value is good enough for power transfer.

We have 240 V series connected 20 Solar Panels, Each 12 V. Which is connected to grid tied inverter. Is it possible to charge a Solar battery without taking line from grid tied inverter? If yes then how??

Hi everyone, I am writing my master thesis in grid forming controllers and I am analyzing Power Synchronization Control as one of the Grid forming control methods. I am dealing with some problems when connecting the current limitation so I wanted to as if there is someone here that simulated the same control method and can help me to clarify some questions.

Thank you !

in islanded mode, if I consider two inverters connected in parallel both working in grid forming mode connected through line impedance what is the procedure of connecting both of them. (How the reference can be created so as to connect them )there may be a phase difference between the two connecting inverters.

While working on SC study on solar plant, I would like to know negative impedance impedance of PV inverters.

I am trying to measure the losses in the output LC filter inductor of my inverter, This is the method I am using so far; I multiply voltage across the inductor and current through the inductor and take the average over one time period of 1/50. The weird thing i observed is that the loss I calculate with this method comes larger than even the total losses of the inverter. Please see the attached picture for my captured voltage across the inductor and current through it.

Hello

Dear researchers

In recent years self-balanced switched capacitor boost Multilevel inverters become a more trending research area. In which the capacitor is connected across the DC source to charge in a short period. But in the practical application how far this is feasible without the current limiting inductor.

1) Maybe in most cases, researchers are assuming the initial capacitor voltage is charged at its rated position. otherwise, it would draw a very high surge current from the input source in starting. In real-time there will be a voltage deterioration when it is not in operation. so if it is switched it will damage the IGBT?

2) I have observed in the MATLAB/ simulation. The switch resistance is considered as 1m.ohms(Ron). Even in normal conditions also the capacitor draws impulses current is nearly 100 times of rated load current. but that impulse is not observed in DSO(oscilloscope) while measuring the capacitor voltage in real-time experimentation may be due to IGBT resistance(it is approximately 14m.ohms).

4) what is the impact of this impulse current on the switch (IGBT) and input DC source during starting and normal conditions? how far this is a problem for the SCMLI.

Thank you for your valuable comments

Hi all,

I am modeling a hydrogen-renewable microgrid and want to use average models of converters and inverters to reduce simulation time (my current microgrid model with IGBT and PWM converter and inverter took 2 hours to simulate 24seconds in Simulink, which is too long). Currently, I have successfully modeled the DC DC boost converter and buck converter, however, for the bidirectional DC DC converter, I have not been able to simulate that. So I wondering if someone had done it in the past and be able to send me the simulation file or any document related to this. Thank you guys so much.

Best regards,

Phan Văn Long

P/S: Below is the simulation file with an average model of DC DC boost converter, buck converter and a average model of bidirectional dc dc converter (connect with a pv panel - mppt boost converter)

Factors to note: roof position; shadow; arrangement of panels; number of panels.

Dear researchers, Hi everyone.

**I am looking for serious and practical collaboration in designing**

*Model Predictive Control (MPC) based Energy Management (MPC-EMS) of a DC Multi-Microgrid system*. The system is already operating in Matlab Simulink software and is ready to update.**Add to this, the control should optimize the battery usage (SOC %), and DG fuel consumption (Liters), besides maintaining Bus voltage regulation for both DC Loads and DC-AC inverter (AC load).**

I will be happy to meet the interested researchers to schedule the working plan.

Thank you.

I want to design a 30MW Solar Plant connected to grid at 230kV can anyone help me with any article or MATLAB file having its design calculation for inverter, Boost converter and MPPT code, and PWM generator control.

I am trying to simulate a micro grid and I need an inverter for a DC source. In my method, this inverter must set I

_{d}and I_{q}values as input references and delivers Active and Reactive power of the source to suitable values according to that references. Can someone help me? thanks so much.If i want to build a system with an off-grid inverter for backup reasons, which will only work when a utility loss occurs, and with an on-grid inverter to work normally during grid presence, can i parallel the same PV strings on their PV inputs?

On that case, when there is sun the PV has energy, therefore, it will inject to the grid and at the same time it will charge the batteries through the off-grid inverter.

The AC circuits of both inverters are separated, the only thing in parallel and connected with each inverter are the PV strings.

Dear researchers,

I am implementing a model for a grid-connected PV-inverter. In the current controller part (see the photo) there are two PI controllers that have an essential effect in calculating the final inverter output. From my trails until now limitations for the PI controllers output are necessary. Has anyone an idea how these limits can be calculated?

Many thanks in advance

Mansour Alramlawi

Hi,

I am working on a model predictive control of inverter using a Microlabbox or DSpace 1102. Recently, I found that working with Microlabbox beyond 2e-5 us is a tough task. I came to know that, for dSPACE1104, there are slave PWM blocks to working with low sampling rates. But unfortunately, there are no such options in Microlabbox. I am aware of the s-functions based model but looking for an alternative to that. I request you to guide me in working with more complex models such as sample-based controllers at low sampling rates. please share some useful information in this regard.

Thanks in advance.

Hi,

SITUATION:

I am trying to recreate something similar to the inverter model contained in:

Conference Paper State-space model of an inverter-based micro-grid

There is a Droop Controller that feeds a Voltage Regulator that feeds a Current Regulator that powers a LCL filter.

MY PROBLEM:

1. When combining the Voltage and Current state models. A and C is 3x3, B and D are 2x8. I pad them out with redundant zeros to make them all 8x8, unsure if this correct? When I multiply them out as listed in the link below, I lose all the controller information from the Current Regulator, such as the integrator and proportional controller coefficients and the decoupling terms.

2. The Voltage and Current state models share the same inputs as the Droop controllers, so they are not perfectly in series. Is there a strategy to combine state space models that share inputs?

Thanks

Hi,

I am designing a CMOS inverter in the cadence tool, can anyone please tell me how to measure its voltage gain?

Thanks

I was modeling STATCOM in MATLAB/SIMULINK for my research.the overall HVDC research network was performed on DIgSILENT. how can I attach the STATCOM to the AC system bus of the Inverter side of the network system

I have read papers on multilevel inverter feeding BLDC motor drives. My question is BLDC motor having trapezoidal back-emf, is it possible to drive the BLDC motor using an l inverter that gives a perfectly sinusoidal voltage output? Also, I would like to get clarified about the stability of such a drive and torque ripple. I will be grateful to you if you could kindly let me know the significance of such an inverter application to BLDC motor drives.

I make a design for a grid-connected LCL filter to be used to connect a single phase inverter to the grid to suppress the injected current harmonics. I would like to know what is the suitable core type to be used for the inductor? Ferrite Cores, powder cores or Tape Wound Cores?

Dear experts,

I am elaborating on the impact of flicker shading from wind turbines on solar inverters.

Racing shadows from wind turbine blade shadows across a solar field impact the current flow at the DC terminals of an inverter. Depending on configuration - just few or multiple strings per MPP tracker - the inverter would want to follow that fluctuating signal.

- What is the follow rate of MPP trackers and conversion electronics on such steep change ramps?
- What is the impact on the inverter life time?
- What is the recommended design?

(Note: the question is NOT about the impact on the plant performance due to shading losses.)

Many thanks for hints or papers.

Best regards

Ralf

Hi,

I am trying to create a full system state space model for an inverter.

References:

Conference Paper State-space model of an inverter-based micro-grid

Both papers have modelled individual controllers and then combined them to create a full system model.

Both have used the same technique, does anyone have any literature on how they came up with a complete system model, that combines all the state space models into one big one?

Regards,

Sandford

why frequency of inverter decreases(while frequency of inverter decided by modulating signal frequency) with increase in load demand ???

What could be the reason for this distortion and the unsymmetrical nature of the waveform measured on the filter capacitor of LCL filter of grid connected inverter? The voltage at the inverter output is normal. DC input was set at 1.08 pu. Could the problem be from the control as well or limited DC input?

Assume we have a microgrid consisting of two inverters

Dear researchers,

I'm trying to implement a two-level three phase inverter.., when I use a three phase resistive load, the output voltage VAN is accurate and it looks like the simulation. However, when I add three inductors to the load (inductive load), the output voltage is distorted and the load current is not sinusoidal (please see the attached images for illustration). I'm using six IGBT transistors IRF G4PC40FD, I think the problem comes from the freewheeling diode of the IGBT transistors. Should I use an antiparallel external diode to eliminate the internal diode of the IGBT ? If yes, please suggest us a practical schematic to get a sinusoidal shape current.

I have two subsystems for a solid state transformer. when the subsystems are not interconnected, they produce the desired results(voltage and current outputs). When the dual active bridge is interconnected with the inverter, unexpected results are achieved. I suspect an issue with the sampling rates of the subsystems. Please help me solve the problem.

I am trying to use the advanced PID controller(auto-tuning) to control the speed of induction motor drive with FOC. I would like to ask how to get the transfer function for the induction motor and inverter by system identification method. anyone can give me useful information.

Voltage state inverter microgrids are used to produce active and reactive power with renewable energy sources. This system is efficient or enough to replace the conventional generation system.

If a photovoltaic power generation system is to be added to the microgrid. The DG will inject active power of 150KW and reactive power of 30KVA into the grid in normal operating conditions. The inverter output voltage is 10KVac and the input voltage is 500Vdc. Use a three-phase inverter. suggest

a)grid-connected inverter for the project

b)control scheme for inverter(VSI)

c)control scheme for islanded necessary conditions

If a UPS is feeding a 30KVA data centre. Recommend or suggest

a)Inverter and its control scheme

b)Control scheme for the inverter

c)If another load of 10KVA is added and new UPS is added in parallel with the previous UPS for the new load. What will be the control scheme for the inverter? in this case.

I have three 1-ph inverters and they are needed to be connected to a 3-ph grid. For such, all the three inverter's output voltage must have equal frequencies and 120 degree phase shifted. In other words, they all must be in synchronization. I'm developing a model using Simulink.

I have completed the simulation of grid tied inverter and got voltage, current, harmonics distortion at PCC but i don't know how to extract features and process the simulation outputs for SVM training and classification in MATLAB

In most of the research papers SVPWM techniques are used for PMSM and other motors after inverter transformation, instead of the PWM technique can I use Sine PWM techniques for motors?

I have designed a control law based on sliding mode control for a grid-tied inverter, the controlled variable follows the positive reference values well, but when it comes to negative reference values it doesn't work.

The DC Voltage is 400 V. The required three phase voltage is 230V, 50Hz.

I am working on a multi-level DC link inverter. I have verified the simulation part in MATLAB/Simulink for R and RL load. when it comes to hardware for R load results are satisfactory, for RL load there is a small voltage dip or surge when the load current crosses zero instant.

I am designing an inverter in Matlab, for desired performance I need to design a close loop model with a PI/PID controller but I am unable to tune the controller gains. Can anybody help me in this regard?

Thanks in advance

Hello,

I am working on a project and we need to use an DC to AC inverter for the battery power supply. I am searching for devices that conver the current and also are capable of controlling the motor. I know that this kind of inverters can regulate the speed. But what about the torque? Does it need to be regulated with a variable resistor? How does it normally work?

Thank you a lot

I'm reaching out because I wanted to know what are some possible pitfalls if a user wants to create two separate strings to drive a grid-tie inverter as an alternative use of the solar water pumping system? Please note that the user wants this kind of mechanical switching to utilize the solar panels while the water pumping will not be necessary.

I'm working on my project for Solar Water Pumping System and my team and I are looking for whatever information you have.

For example, if the inverter is fed with a 100 kW DC battery and the inverter has to run with 0.9 power factor, it will produce 90 kW of AC power, and the rest 10 kVAr (assuming 100% efficiency of the inverter) will be the reactive power. Here the 10 KVAr is getting generated from the 100 kW DC power. Did I understand correctly?

Is it possible that the inverter will convert all the DC power to real power (100 kW DC to 100 kW AC power) and the necessary reactive power (10 kVAr) can be provided from the auxiliary power supply of the inverter?

Your answer will be highly appreciated. Thank you

Grid Inertia is an impending problem if the traditional power systems are decommissioned and replaced with inverter based generation according to some literature. Please, can't this problems be solved by appropriate control active and reactive power ?

can i use firing pulse generator for the battery inverter

I am simulating a power converter circuit on Simulink platform. This also include a 400 V AC grid. I am not sure about a generic thumb rule to define the impedance of the cables for this 3ph 400V Grid system. Any suggestions?

Inverter generation is increasing significantly. The traditional protection schemes in distribution circuits are not well suited to locating faults where there is no overcurrent. What approaches have been tried and what are their success rates.

In a MicroGrid, a fault does not increase the inverter output but the output voltage is reduced and this is the only indication of a fault but the entire network sees essentially the same voltage. The fuses and other overcurrent devices likely are challenged to be able to isolate the faults so it seems that a trial and error approach of circuit isolation and restoration is the best method at this time.

Comments on approaches that have been tried with their effectiveness is most appreciated.

I am designing a control system for Hybrid renewable energy systems using Matlab/simulink/simscape, but currently having a problem. Whenever I run the simulation, I get the error shown below.

"

**The following block is not supported in Phasor simulation method: Block : FLC_HRES_Controller/Inverter (Three-Phase)/Detailed/Detailed Type : Universal Bridge**"What is the way around this?

Who will help?

I) How do I measure common mode voltage in matlab simulation?

II) After knowing the value of the common mode voltage, how do I see the behavior of this voltage together with the stray capacitance generating the leakage current?

III) For example, with this circuit (a), where would I have to measure to get these graphs of common mode voltage and leakage current (b)?

*Figures: M. N. H. Khan, M. Forouzesh, Y. P. Siwakoti, L. Li, T. Kerekes and F. Blaabjerg, "Transformerless Inverter Topologies for Single-Phase Photovoltaic Systems: A Comparative Review," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 8, no. 1, pp. 805-835, March 2020, doi: 10.1109/JESTPE.2019.2908672.*

Aoa. I hope you all are fine. I want to know which topolgy/technique of ZSI is more efficient and how we calculate power flow in qZS inverter?

Which PWM technique is better for qZSI and why?

LCL filter are used for grid connected three phase inverters. The design of LCL filter is tricky as it can effect the stability of the system. During the design of LCL filter, to calculate converter side inductor, first maximum current ripple is calculated as

∆i_max=V_dc/(6L_i f_sw )

In above equation both ∆i_max and Li are unkown, so some authors[1] suggest to use 10% of Imax for this ripple current. On the other hand, other paper for example [2] and [3] use a relatively complex method to calculate the value of ∆i_max.

My first question is how accurate is use of 10%*Imax approximation? Are there any other quick way or approximations according to standards to find ∆i_max.

My second question is how to find the right attenuation factor δ for particular value of THD?

[1]M. Dursun and M. K. DÖŞOĞLU, "LCL Filter Design for Grid Connected Three-Phase Inverter,"

*2018 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT)*, 2018, pp. 1-4, doi: 10.1109/ISMSIT.2018.8567054.[2]Said-Romdhane, M.B.; Naouar, M.W.; Belkhodja, I.S.; Monmasson, E. An Improved LCL Filter Design in Order to Ensure Stability without Damping and Despite Large Grid Impedance Variations.

*Energies***2017**,*10*, 336. https://doi.org/10.3390/en1003033M. Ben Saïd-Romdhane, M.W. Naouar, I. Slama. Belkhodja, E. Monmasson,

[3]Simple and systematic LCL filter design for three-phase grid-connected power converters,

Mathematics and Computers in Simulation, Volume 130,2016,Pages 181-193,ISSN 0378-4754,

I'm working on an induction motor drive with a scalar controller. As inverter modulation, I utilized both SVM and SPWM. I discovered that if the frequency and output fundamental voltage from SVM and SPWM are the same, the THD is about the same. The result can be seen in the image attached herewith. Can anybody explain why the THD is the same? Is THD only determined by the amount of fundamental voltage generated? Any literary references would be much appreciated.

I am working on a Three-phase Two-stage Grid-connected PV Solar based on boost converter& Inverter with P&O Algorithm, but the pv array is producing a negative current,

I can't tell why, My first reaction was to go over the schematic and each component multiple times, I pretty much checked every component, I tested it before and it worked just fine.

here's my simulink model:

Does anyone have the PSO-based MATLAB code for calculating the PDP of the inverter and Full Adder circuit?

Hello everyone.

I am working on fault diagnosis on inverter and I don't know how to pass from signature matrix to proper fault classification. Should I use mathematical modeling of the system?

Thank you.

Lucresse Francelle Towa

phD student

University of Yaounde I

If we design Single phase inverter or Three phase inverter with Induction motor as Load,

What do you think about DC Link ?

Shall DC Link be a storage Capacitor or simply Harmonic Elimination Capacitor ?

How Capacitor Should be selected ? Based on voltage or Capacitance and type of capacitor ?

I am using PSCAD, kindly help me ASAP to find solution

There are 2 big issues, while doing our research

1. During implementation of our circuit, we are facing problem regarding the connection of Capacitor module into inverter side. How can we overcome this?

2. During implementation, we have to integrate the control section of Capacitor module as well. But, we don't much about the modules used in control. How can we overcome it?

I am looking for new interesting fields to do research on power electronics.

To obtain dq components of the inverter voltage for unity power factor correction of a 3 phase induction motor

What is the modulation index (m

_{a}) which is mentioned in the 2.2 equation?In both Grid connected and stand alone Solar PV system an inverter is used. Please clarify if we can use a same inverter for both grid connected and stand alone operation of solar PV systems?

Iam not getting how to give dead time in single phase inverter operation via TL494 IC. I tried giving some voltage on DTC pin(4) but not getting dead time between complementary signals. So, please if anyone used TL494 for the same purpose, please help me.

Here iam attaching connection diagram of TL494 and complementary outputs(pin 8, 10).

switching freq= 200kHz

output has taken from pin 8,10 in single ended mode(parallel mode)

DTC pin is initially grounded to get 3% dead time (150 ns). Later i tried giving some voltage on the DTC pin. Still, the dead time is not coming.

I am a mechanical student with no background in BLDC motor modelling. Can anyone help me with this? I need it to find the heat generated in the inverter. I have created the vehicle model for the simulation which uses NEDC drive cycle. I got angular velocity and load torque from that. I don't know how to proceed further when it comes to BLDC motor.