Questions related to Power Converters
Hello, I have a real problem statement from wind industry. Does, anyone suggest the solution.
We have power converters for 2-3MW wind turbine and their failures are a cause of concern, I know there is peak wind season is going on which may be the one of the reason of failures.
Can anyone suggest the other causes of failures and possible solutions? Please share if any case study available in public domain.
Any researcher who is interested in working together in the field of Powers Electronics & Drives, Converter & Inverter Design, MPPT Techniques, Solar Photovoltaic Systems, Microgrid, EV Charging Stations. And also interested in publishing good quality paper. Kindly contact me. And also here Give your suggestion and feedback.
I have designed a Buck converter hardware setup, using MITSUBISHI IGBT MODULES
CM150DU-12H, L=2mH, C=1000uH, Dutycycle=50%, input voltage = 30, in this scenario am getting output voltage same as input voltage, even though by changing the duty cycle???? any solutions for this?
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 !
I'm trying to control a pmsm current using finite control set MPC using the book (PID and Predictive Control of Electrical Drives and Power Converters using MATLAB / Simulink), when I'm using PMSM model in simscape everything is fine and currents can track id and iq (currents in dq reference frame) but the problem is PMSM model is based on modified park transform (90 degree behind phase a) and our calculations are based on original park.
when I change the PMSM model park transform to original park results change and FCS-MPC does not work properly.
does anybody have this problem?
Thank you in advance
I want help to evaluation efficiency of DC-DC power converter with Matlab/Simulink. Is there any block for the calculation? Please share any ideas regarding this.
(I have asked this questions previously, but I believe it was too general. I have tried to be more specific here)
I am trying to establish an islanded microgrid with 2 inverters running in parallel to supply a single load. I want to use droop control so I can then adjust the power sharing between them.
I am struggling to get 2 inverters to synchronise. I can get them to supply the same voltage, but the currents work against each other in the load.
What I have tried:
1. Grid forming and Grid feeding. When I add the Grid feeding inverter, I can not control the voltage that it injects the current at. If I give it it a Reactive power reference, it will inject current into the grid at that power level, it doesn't regulate the voltage. Therefore, it pushes the voltage of the load up I get instability in the system.
2. Grid supporting Voltage x 2. I have tried to put 2 Grid supporting Voltage sources in parallel. The problem here, is that if each inverter supplies a different power, this then adjusts the frequency that is injects its power into the grid and the miss match between the two frequencies of the inverters causes instability.
3. Grid supporting Voltage and Grid supporting Current. This has the same issue as point number 1. As there is no way to pin the voltage to anything, it is simply a current source that cant control the voltage it injects at. This causes instability in the microgrid I created.
Am I doing something wrong ?
The following paper has exactly what I am trying to achieve, but I get different results:
Does anyone have a Simulink model of 2 parallel inverters supplying a load in islanded mode?
Attached is the model of the Grid Supporting Voltage inverters in parallel that I have been working on. You can see that the currents of each inverter are working against each other.
I am currently working on my PhD in Control Engineering. I have run into a brick wall and it has consumed months of my time. I understand the following:
There are 4 types of configurations for a power converter:
Grid Supporting Current
Grid Supporting Voltage
I am using the following paper to try and establish a microgrid of parallel converter:
1. When I establish a Grid Forming power converter, I set the w and v of the grid. I am then using a second Grid Supporting Current power converter, but the voltage of the grid become unstable. I have read in other threads that Grid Forming power converters cannot run in parallel with any other converters. I assume this is why this started.
2. I then try to establish 2 Grid Supporting Current power converters to run in parallel with each other. However, there doesn't really seem to be a way that I can synchronise them. I can get them to run when the power on the droop controller is the same, therefore the w are both the same and they synchronise. I tried to switch one of them for a Grid Feeding power converter, again this did the same as in part 1, it adjusted the voltage and it became unstable.
3. All of the models I have come across take the inner current loop voltage readers before the Capacitor but after the Inductor, as in the paper mentioned above. However, Simulink gives me an error about zero crossings, when I override it the AC output has major distortion in it.
How can I create a Simulink model with two parallel converters to run together ?
My goal is to create two or more parallel converters providing a single load so that I can create a controller that provides stability under actuator attacks.
The other papers I have based this off are:
You can see from these articles that the current reading is taken before the capacitor bank.
I am looking for information that mentions the control strategies in direct current to direct current converters, which can facilitate a summary of the state of the art. Any information is welcome.
If you know of some control methods / strategies and can mention it, it would be helpful.
Hi all, I am looking for literature on the topic of Power converter layout. Does anybody have recommendations for thier favourite and most usefull books, articles, application notes?
Due to the increasing penetration of distributed energy resources (DERs), various inertia emulation methods have been recently proposed for the interfaced power converters. These methods intentionally slow down the converter frequency response speed. In this case, the power converters are able to keep pace and play well with conventional synchronous generators.
However, it is also envisioned that a 100% DER penetration level may be realized in the future. In that case, is it meaningful to pursue the "inertia" concept? especially when all the power converters can maintain synchronization and frequency stabilization within an extremely short period of time.
Rotational loads are definitely linked to the reactive power readings in distribution network.
Are there any direct or indirect relationships derived between the two?
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 suggest to use 10% of Imax for this ripple current. On the other hand, other paper for example  and  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?
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.
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/en1003033
M. Ben Saïd-Romdhane, M.W. Naouar, I. Slama. Belkhodja, E. Monmasson,
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,
hello, i try to model my boost and buck-boost converter in simulink using the state space averaging technique, but what I see in the literature that the dynamic equations differs depending on the conduction mode if it is continuous or discontinuous.. My question is if I want to do my simulation, should I suppose that I am working in only one conduction mode for ex in CCM and then continue working based on that ? if yes, what are the consequences of not considering the other conduction mode ?
In a typical multi-loop digital control scheme for power converters, generally, there is an inner current control loop that provides the reference for PWM gate generation. Also, an outer loop control is used to produce the current reference (DQ current for a three-phase system) for the current controller. A designer can select either voltage or power controller as the outer control loop.
My question is what are the criteria to select a controller between voltage and power as the outer loop? Can anyone please enlighten me when we should select a power controller as the outer loop? When we should select a voltage controller instead of a power controller as the outer loop?
Thanks a bunch in advance for your time and suggestion :) .
When mosfet is turned off there is a reverse voltage across body diode and the depletion region of drain-source diode(Cds) gets charged. As for the diode, it is forward biased and there is no stored charge across its depletion capacitance(Cj). When we turn on the mos the stored charge in Cds gets dumped into the channel of mosfet and gets wasted and the Cj gets charged. During the turn off transition of mos the Cds gets charged now and the charge stored in Cj gets discharged through the load. Here it is said that the energy lost during turn on transition is 0.5(Cds+Cj)(Vg^2). From my understanding I think that the lost energy is of the energy stored in Cds and Cj discharges its energy back to the load(during the turn off transition of mos). But that doesn't add up with the result given here. Please correct me if I am wrong and explain what is going on.
Thanks in advance
In this circuit the capacitor is junction capacitance of diode and ringing takes place here. The third plot is voltage across diode. As the stored minority charge inductor is stored with negative current and it need a path to flow. My doubt is where does this current actually(physically) flow? I mean the junction capacitance is modelled from the depletion region meaning that it will flow through diode again but diode cant conduct in negative direction. Please explain me what is exactly going on here and tell me where am I going wrong.
Thanks in advance
I am working on a project in which I need to control the duty cycle of the pulse given to mosfet in an AC to DC converter.The mosfets are connected to LCL filter to give a regualted 5V.The output voltage and a reference of 5V error is taken and a compensator is connected.The output is compared using PWM and then sent to mosfet.Do we need mosfet driver in between?What kind of mosfet driver should I use in multisim?Can I get any reference?Should we solve this using bode plot?Should I use PID controller to decrease the error and should I simulate in MATLAB using PID controller ?As I find it easy
Dealing with LLC resonant converter simulation and would like to plot the efficiency curve. How Can I do that ? eff = Pout/Pin ( Pout I can calculate from Output voltage and current but input current seems to be partial sinusoidal and cannot deal with any calculation !)
I am designing a control for bi-directional LLC-SRC DC-DC converter. The converter charges a battery from the grid. But during reverse operation, i.e when the current flows from battery towards the grid, what may be the impacts of current on the resonant capacitor (Cs as attached)? Do I need to wait for the discharge of DC link capacitors (fast/slow anyhow) on both sides? I cannot see any abnormal change or fluctuations during simulations. For practical approach, I am not sure. Any suggestions?
Hello Technician and Academician
Can somebody please inform me, what is actually the type/topology of power converter available at the market for small wind turbines (below 10kW) with PMSG? especially for the rectifier part, is it just simple rectifier or controlled rectifier, with thyristor or MOSFET?
what are the dominant topology people used? for offgrid and ongrid
if you check IEEExplore, then soo many types, but I cannot find the reality in the market
what people recently use actually?
Can anyone recommend good tutorial materials and literature on 'grid forming and grid following converter models'?. I will appreciate your recommendations and suggestions. Thanks.
Mostly, PLL is mostly employed to generate the phase angle of PCC voltage in grid-following controlled converter. However, the phase angle can also be directly computed from abc voltage (first do the clark transformation to alpha-beta than calculate the anti-trigonometric). The fluctuations of the result caused by harmonics can be filtered someway, i suppose. Isn't it an easier and more reliable way than PLL?
I'm developing a Bachelor Teases about the economic impact of inserting a BESS into a MV level load. One of the requirements is to include a step-by-step on how to buy a commercial inverter for the required Energy Storage Systems composed of Li-Ion batteries. Any kind of material would be highly appreciated! Thanks!
For a switched-mode power supply, can volt second balance be applied to capacitor voltages too at different operating modes or is it only restricted to inductors?
Is it technically correct to express capacitor voltages in terms of the inductor, so as to apply VSB?
Please explain in detail!
- While I am doing MMC design simulation, I always find that all capacitors of MMC work in the same time.
is there away to sort them but without one by one condition ?
- Do MMC need P&ID for capacitor voltages?
I am working in the area of DC Microgrid in this regards I need a DC-DC converter. I will be thankful for this act of kindness.
I want to validate control scheme using DSP and Hardware setup, which i design in MATLAB simulink. So is there any reference guide book, which can guide me through every step from prototyping to generating code in Simulink or PSIM and test it on prototype.
I have a tank of lube oil which is not insulated and top of tank is a compartment, in other words, tank is the bottom of the auxiliary compartment. The volume of tank is 25.000 liters. Because we will flush the pipes with lube oil pump (90 KW), the temperature of oil will increase by time. I assumed 50% of pump power will be converted into heat in oil and the oil will increase 4 celcius/hour. But i dont know how to calculate the heat exchange between oil in tank and ambient. Does anyone know a simple formula to calculate hourly heat exchange (Celcius/Hour) of mass oil inside a tank and ambient ?
I have been trying to simulate an MMC in a rectifier-mode using PWM.
First, I modeled a single phase MMC on PSIM software and simulated it in an inverter-mode, and made sure it worked. Then I connected a voltage source on the AC side and loaded the converter on the DC side (effectively making it operate as a rectifier), using the same PWM scheme. I get a zero voltage at the DC side as the AC source seems to be shorted through both the upper and lower arms, hence there is no voltage between the positive and the negative output DC terminals. Is there any difference in terms of modulation, structure, or any other, between an MMC rectifier and an MMC inverter? Most research papers seem to talk about an MMC inverter, never touching on the MMC rectifier.
Thanks in advance for your contribution.
I want to understand the basic difference between these two converters. Also, how is a grid forming converter supposed to improve the voltage quality of the grid as it requires the voltage reference from the grid itself ? (Correct me if i am wrong).
Moreover, can a converter be both (grid forming and grid supporting) at the same time or one or another in the same structure with conditions like transition ?
Can't we design the MPC Control for a system whose model is not known, but all the quantities are measurable? I am working on a bidirectional DC-DC converter which involves switching of power electronic devices and the exact model of the system is not known. Can't we design MPC for this system in MATLAB, if the quantities associated with the system can be measurable? Please give specific suggestions in this regard.
I am trying to design an optimal fractional order PID controller for a buck converter. Can anyone suggest how to decide the time integral performance criteria to be selected? Can an ITSE error of zero be achieved?Also, can anyone suggest any books or papers which clearly explain the procedure of optimization of PID and FOPID controllers? Thanks in advance.
I was looking for an active-bridge rectifier. The active-bridge is superior in terms of efficiency if compared with the conventional diode-bridge rectifier. The only solution I found was IR1161L which is a synchronous FET controller in secondary side rectification in power converters such as flyback and resonant half-bridge converters. For active-bridge rectifier, we can use 4 of IR1161L to drive the four FETs of the active-bridge. Unfortunately, Infineon doesn't offer a spice model for this IC and there is no way to test it's performance.
If there is an alternative solution that has a spice model please suggest.
I am an Electrical Engineer in a Dutch startup, & looking for the research team who is working on some electronics project, well that's a very big topic by naming just Electrical or Electronics. But any project related to the subject I would be interested to join.
Pls, let me know if group/individual would like to join me in their group or individual who wants to work with me on some project(can discuss separately).
I have done some research/projects in my current company like reducing Inrush current in television, Circuit design for a small oven, Design of LED batten, Programming of Power converter through a USB port etc.
As far as I know, the control structures of grid-forming converters can be classified into 2 categories: one is single-loop without current control loop; the other includes a voltage loop and an inner current loop. What's the advantages and disadvantages between them two? Which one is more promising?
Please suggest me suitable power electronics converter which can extract current of a particular frequency from a multi-frequency voltage bus at high power level.
Multi-frequency bus voltage
V = V1sin(w1t+phi1)+V2sin(w2t+phi2)+V3sin(w3t+phi3)+V4sin(w4t+phi4)
and I want a power electronics converter and load to connect across this voltage, but the converter should draw current of particular frequency only, say for example: i =I3sin(w3t+theta3), (see attached figure)
Please suggest me suitable power converter for this.
Is it possible to do so, without using passive LC filters?
Good morning, regarding synch of power converters to grid I note that the basic approach for PLL is trying to reduce the phase error i.e the difference between the real and estimated phase angle.
To that end a Park transformation is applied to convert the abc voltages to dq voltages via Park transformation.
I note that in several papers the Vq component is used to compute the phase error while in others Vp is used.
Would you kindly advice which option is preferable in your opinion.
Thanks in advance a Merry NY2K20!
I need to provide an isolated voltage sensing for control circuitry of a DC-DC power converter (it needs to sense the 350 VDC output voltage). Does anyone have any recommendation about selecting an appropriate voltage sensor IC? Requirements:
- High common-mode transient immunity (preferably above 50 Kv/us)
- Very Low Delay
How to calculate the settling time for the PV MPPT controller?
I mean for example if the operating conditions are changed: solar radiation, the duty cycle, etc.
How much time the does system need to reach the steady-state condition?
I want to design the filter for DC-AC converter topology which is half bridge. I'm using SiC MOSFET for that. Input voltage = 560V, Output voltage = 500V. I'm using Plecs + MATLAB for designing the Circuit. I want to reduce the losses so that it will be less that 200W overall.
#powerelectronics #electrical #semiconductor #powerengineering #Convertertopology
The increase in the trend of distributed generation has led to the formation of community microgrids. What is the best possible solution to connect single-phase loads to a microgrid with 2 level voltage source converter?
I feel one possible solution to connect single-phase loads is to use a 3-phase 4 -wire transformer.
my question is why and how fuzzy logic can perform better than conventional MPPT methods such as : P&O method ?
I found that fuzzy logic can eliminate the slow tracking speed and the oscillation around Maximum power point (MPP)which are the two common drawbacks of the P&O method.
Well .. my question is too simple.
I need to know how to model rectifier circuit in state space model [A B C D]
rectifier circuit simply consists of: voltage source, MAYBE line inductane, 3phase rectifier diode, load (resistive .. if I can make a model reliable for different type of loads, that's a plus ! ).
Power converters for rural electrification comes on all shapes and sizes. However, in the OwnPower project we seek to develop converters which are multi-functional and multi-tier.
If you could wish for a power converter that could take care of all of your field problems, which functions would you like this converter to have?
(DC/DC, DC/AC, step-up, step-down, isolation, high-power, etc...)
This might be a too general question, but:
In power electronics applications (such as DC-DC converters and such) and for switching frequencies of "a few hundred KHz", in general which one has lower core losses as a core of a power inductor (say for example an output filter inductor) : a "ferrite core" or a " powder core" ?
or is there any new material that can outperform those materials in terms of core losses (that can also handle power levels from a few kW to a few tens of kW)?
in a 3 phase application, SVPWM output is gates S1S3S5 .. but If I made modeling to my system in dq frame, HOW I can convert S1S3S5 to dq frame to suit my modeling system?
I am new to simulink and am simulating a PV module with a buck converter. As you see from the equation of the output current eq(1), there will be algebraic loop. I tried a unit delay and memory to break it, it works when I test the PV module alone with a variable resistance at the output and it yeled correct results. But a unit delay or memory blocks can change the dynamic behavior of the system, so is there a way to get around the algebraic loop problem ?
I am using HCPL 316J IC as gate driver for matrix converter application. The system is running completely fine on RL load. But on running a motor load from the converter, it is observed that as soon as the motor accelerates, the gate pulses are withdrawn by driver ICs which then require manual resetting to re-issue gating signals. An obvious guess would be overcurrent DESAT protection getting enabled...but i have disabled the DESAT pin in the PCB design by grounding it.
in these days, SiC power electronic devices are being popular in different applications. For medium voltage direct current (MVDC) converters based on SiC technology, there are some effects imposed SiC converters due to load and supply variations. My question is that, How do these variations affect the switching performance of SiC based power converters in MVDC systems?
Thank you in advance,
I am opening a serious discussion for the validity of implementing the SHE modulation for a specific three phase converters controlled by Vector Control and regulating the DC-Link. Implementing SHE as open loop control (fixed modulation index and arbitrary phase shift) is visible and easy. Also, single phase implementation is easy and really visible for open loop (99% of research using open loop).
Here is the issue for 3-phase converter: to eliminate the harmonics, the pulse pattern must be produced for a complete period (20 ms for 50 Hz) for each phase. this means the sampling time for the control loop should be 20 ms ( too slow). in other words, let us check only for Phase A. the pattern need to be ready each period (20 ms) and the SHE will not update the its reference angles during executing the full pattern with takes 20 ms. This concept is also applied for phase B and C. Otherwise, if we contentiously update the modulation index and the converter vector phase shift (relative to grid vector), the SHE becomes some sort of random PWM pattern.
The Question is: Is SHE valid for controlling three phase converters using vector control method in a closed loop control strategy?
I want to use a single circuit for accelerating the motor in bi-direction ,and also want the same circuit to provide dynamic braking for the motor. Will a buck-boost converter be helpful when I am using a micro-controller as a master control for the circuit?
I want to charge series connected 4 lead acid batteries (all of them are the same ) from a solar panel using a power converter with MPPT. Since these 4 are connected in series, they will charge and discharge at different rate (voltage for each will be different). Hence, I need a resistive attenuator for
Charge equalization. Now the issue with that is, I am working with 250W panel (high power), which causes a problem. Now:
1- I cannot know the voltage drop for each since it has to be above the rated voltage for charging.
2- Connecting them in parallel with a diode for each branch, but I cannot grantee that there will be no circulation of current in them.
I thought about charging these batteries individually based measurement of currents/ voltages that will be the job of a controller. So:
1-Is there something like a changeover (switching circuit) I can implement to overcome this issue?
2-Which connection of these batteries is best for impedance matching?
any advice or help is appreciated.
I have been thinking in how to Speed up the performance in DC-DC Power Converter?, because I have a systems which has 2 DC-DC converters, the first one is working in order to obtaing the highest solar harvesting under a MPPT control and recharging a battery bank, but after it there is a second one DC-DC converter which is aimed to maintain the output voltage within the safe values range. Notwithstanding, I have noticed that the simulation go slower than I would like, in many cases it take bout a week for running a 24 hours simulation.
Could you help me with this issue?.
What are the expressions inside High voltage reactive current logic and Low voltage active current logic blocks? Only two parameters are given:VHVRCR (High voltage reactive current voltage ) and CURHVRCR (max.reactive current at VHVRCR).
In these days, I am studying MPC control on inverters. I do the model predictive control of a grid connected inverter with LCL filter, to be more specific , finite set MPC control with long predictive horizon.
I would like to tell you why I want to implement MPC method to the gird inverter. When I entered my supervisor's team, they focus on control method on power electronics. At that time, my supervisor, Mr Long, told me MPC control is pretty popular in recent years, and suggested me to value such a control method to do a further study. So firstly, I read the book Model Predictive Control of High Power Converters and Industrial Drives written by Tobias Greyer, and found FSMPC with long horizon is much better than that with short horizon. As a result, after understanding the principle in that book, I want to do some simulations to see whether I can implement such control method into the inverter. But during simulation, I faced some troubles. . Everyday I suffered finishing all kinds of troubles. At these days, I constructed the whole simulation and wrote the code for mpc block, but it doesn't work.
So I'd like to get your hand to solve the problems. Below, I show you what I have done in these two weeks.
I am working on the prototype of a three phase bidirectional dual active bridge DC DC converter?I am having DC offset in the current on the primary side of the transformers which is causing loss of efficiency.I would be grateful if any one in this community can shed some light on the potential causes of DC offset?
Good Day all,
I started learning SMC for power converters and got some basic principles of it. However, If I am not wrong, MPC is also becoming popular these days. So, please clarify me " what are the performance differences between the two control methods and when to use the specific controller? "
Thanks in Advance.
I am currently studying grid-tied converters and in order to have accurate simulation results I would like to the know the impedance value of the low voltage distribution grid ( Vrms= 260V , f=50 Hz)
Is there anyone who his field of study is related to electrical power systems and knows the typical impedance values?
Thanks in advance.
The are many devices for wave energy extraction like offshore devices, onshore devices and near shore devices. I want to know from you the name of wave power converters from off shore devices.
There are many publications about HVDC and MMC converters, and there are also different tunings for the classical PI controllers for the current controllers.
If there are hundreds of submodules, what would the typical values for the time responses of the circulating currents (also called differential currents)?
It was seen from the simulation , that a PI controlled DC-DC boost converter is having ringing effect when an input line variation is applied. The ringing amplitude is high. And the ringing frequency is found to be less than the cut off frequency of the open loop transfer function. Is there any method by which I can reduce the effect of ringing amplitude as well as the ringing oscillations?
I want to use comsol software to simulate provskite solar cells, I dont know what kind of information is needed to simulate different layers and finally extract the best power converting effeciency ( PCE%)
Please guide me.