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cristi7521

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  1. Ce numar de ore de functionare au (aproximativ)?
  2. Pentru sursa de 7kW de mai sus am analizat blocul redresare si filtrare. Date initiale: -transformator retea 230V , lungime cablu de conexiune catre amplificator 30m cu fir de cupru 6mmp (aproximativ 0.2ohm rezistenta); -filtrare ca in schema 4 condensatori 2200uF/200V; -aleg condensatori Vishay Power High Ripple Current 101/102 PHR-ST care au ESR max 67mohm si Iripple = 8A la 100Hz - 20$ bucata; - pun datele in LTspice (pun 60mohm ESR); -sarcina de 10.2 ohmi astfel incat sa trag 7KW (nu am luat in considerare randamentul sursei); -tensiunea filtrata variaza intre 305V si 226V; - Ipeak to peak prin condensator = 59A , Irms cond = 20A, putere disipata pe condensator = 23.7W Condensatorii trebuie sa suporte si riplul de curent de inalta frecventa, mai suporta??? Schema este atasata. 7kw-current-ripple.asc
  3. Poate posteaza cineva poze si cu niste radiatoare care pot disipa peste 1KW, asta pentru ca am considerat un randament de 85% (la 7KW) care de obicei nu este atins de flyback. Daca se poate vreau sa vad si sistemul de alimentare care sa duca 7KW in mod continuu: priza, cablu, stecher. Presupun ca am deja transformatorul de Electrica in debara.
  4. Daca ne uitam la filtrare (punte 35A si 2200uF/400V) si tinem cont de anumite reguli de proiectare ne dam seama ca au uitat sa puna punctul intre 1 si 4, deci este cam 1.4KW. Si cele 3 IGBT-uri tot cam spre puterea aceea duc. Schema postata de Marian, deoarece nu are condensatori in primar, nu asigura stabilizarea atunci cand tensiunea de la retea trece prin zero, deci timp de aproximativ 1ms (depinde de proiectare) sarcina trage si descarca condensatorii din secundar, tensiunea scazand in acest timp. Pare sa fie proiectata pentru aproximativ 500-600W, dar pare ciudat varful de curent de peste 20A prin tranzistor de 17A.
  5. Multumesc pentru schema. Nu se vedea bine tipul tranzistorului Q1. Am cumparat acum ceva timp de pe forum o sursa destinata amplificatoarelor clasa D ce scoate +-35V, +-15V, are in primar 2x82uF si tranzistorul este asemanator (15A sau 17A). Configuratia cred ca era tot flyback. Puterea data de producator este 100W continuu cu max. 200W pentru 2 secunde. O sa o caut sa postez mai multe informatii despre ea.
  6. @Marian, poti pune schema la o rezolutie mai buna? Cred ca acest review de pe amazon da mai multe detalii: Technical teardown: There is a switching power supply that runs at 330kHz and supplies +/- 36V rails for the amplifier ICs. The HF amp is an ST TDA7294 linear amp IC that is rated for 100W. The LF amp is an NXP TDA8953 switching amplifier rated at 420W at 93% efficiency. The signal op amps are MC33178 (6). There is an ST ARM Cortex M3 uC 32F100 with 128k flash. This seems like overkill to run an LCD. There is an Analog Devices ADAU1701 DSP with 2 ADCs and 4 DACs built in. This is where the EQ and clipping detection and limiting happen. It's all good circuitry but the TDA7294 is horribly inefficient. I'm surprised they didn't use a switching amp for this unless they are concerned about a switcher not performing well enough at high frequencies. The LF amp is very nice but VERY under utilized as it only outputs about 10W RMS max. Technical sound test: I uses a pink noise generator and ran the volume up until the LCD/DSP displayed "limit". The measured SPL with C weighting at 1 meter was 117dB. Turning it up all the way only increased the output by 1dB. I then changed the signal to 1kHz sine wave. The output at 1meter was 111dB before the LCD/DSP said it was at "limit". Increasing the volume to the max increase the output to 118kB. This output is far from the advertized and specified output power of 127dB. This is very disappointing and disturbing that EV would lie so much about the specs. I have been a fan of EV for 25 years because they have typically done a very good job on specs. They advertize a 1000 watt amplifier which is true IF it was configured correctly. Unfortunately the power supply is not capable of supplying the specified power as it is configured. With a 72Vpp PS, the peak into 8 ohms is 650W and 450W RMS but the DSP limits it much more. I measured the input power (the 120VAC input on the power cord) at 3 different conditions: during idle the power consumption is 20W, during full power (no clipping) the power consumption is 55W, during full power with clipping the power consumption is about 110W. Assuming a 93% efficient amp for the LF and 40% efficient amp for the HF, the combined output can only be about 15 Watts. 15 watts of output is far from 1000.
  7. Se pare ca ar fi in postul https://forum.allaboutcircuits.com/threads/simulating-cd4541-in-ltspice-stuck.142904/ L-ai incercat?
  8. Cam toti producatorii au application note. Pentru puterimai mari se refac calculele si se aleg componentele corespunzatoare. https://www.infineon.com/cms/de/product/evaluation-boards/eval_3kw_db_pfc_c7/
  9. Testeaza IR2110 separat. Il alimentezi la 12-15V, conectezi VB cu VCC si VDD la 12V, VS cu COM, VSS si SD la masa, intrarile le conectezi o data la VDD si o data la VSS. Iesirile trebuie sa comute simultan cu intrarile si pe acelasi nivel logic.
  10. @nel65, de ce nu incerci splan pentru desenat schema? text
  11. Am adaugat din nou arhiva cu: - fisierele lay. - date despre infasurari la transformatorul de la sursa cu TOP244 - flyback. - fisierele firmware pentru invertor de 140A, 160A, 180A, 200A, 220A si poze setari fusebits. - o schema simpla de programator pe portul serial si software Ponyprog cu care se poate programa Atmega8a http://www.mediafire.com/file/cvk4i8krkkvs2ff/invertor-atmega8-pcb-prog-flybac-transformer.zip/file
  12. Gasesti un exemplu de calcul in topicul lui Marian cu sarcina activa
  13. IGBT-urile sunt mai robuste, la puteri mari se folosesc numai IGBT-uri. Seriile mai vechi aveau parametrul short circuit withstand time de ordinul 10us, din pacate la seriile noi a scazut la 5us sau chiar mai putin.
  14. Pentru 1kW se pare ca si IRFP460 sunt cam la limita. Mai exista un topic realizare invertor 800w unde se gasesc informatii utile. Schema puntea H https://www.scribd.com/document/405728392/punte-H-cu-eg
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