Peer-to-peer, engineer-to-engineer questions and answers from the EDABoard.com engineering community around power electronics. Click the “Read more” link and follow the entire conversation and maybe add your two cents by logging in to EDAboard.com

Flyback SMPS power MOSFET getting hot – I built this flyback SMPS transformer for this circuit as shown above using PQ3230 core with Nprim = 24T (swg 26 x 4) , Nsec = 4T(swg 23 x 4) & Naux = 5T(swg 26 x 1) but the SMPS power FET is getting hot even without load as shown in below image. Read more

IGBT overshoot and weird slope – I’m trying to build a 3phase-3phase direct converter (explains my schematics). I’m testing IGBT stage with DC source. The circuit is now just triggering IGBT named SAAF. Read more

IGBT to work at duty cycles up to 100 –  I am designing an IGBT based chopper with single low-side switching IGBT (chose low side switching because of ease of driving the IGBT.)  Is it possible to operate IGBT up to 100% duty cycle? I couldn’t find many application references for IGBTs, which works in the duty cycle close to 100%. Read more

Looking for a suitable DC-DC buck converter topology – I am thinking of modifying my buck converter. It has a high current application. Kindly suggest a design that has:
1. Less switching loss.
2. Less stress on switch.
3. Less number of component.
4. ZVS or ZCS idea.
5. Suitable ripple minimization.
6. Suitable couple inductor design.
Read more

PV with Arduino and 12 V sealed lead acid battery – I have bought this solar charger (Epsolar-LS0512E): https://www.manualslib.com/manual/97…12.html#manual , a 12 Volt Sealed Lead Acid battery, and I use this solar panel: Voltage: 12V Peak Power: 40 W Number of Cell: 36 Pcs Short Circuit Current (Isc): 2.47 A Open Circuit Voltage (Voc): 21.82 V Maximum Power Current (Imp): 2.27 A Maximum PowerVoltage (Vmp): 17.6 V. I want to supply a load, and by reading the solar charger manual it says to use fuses. I use special cable (4mm) for DC current from solar panel to the solar charger. My question is what fuses should I use? Is there any special fuses for PV? Read more

Half-bridge SMPS transformer  –  I  have to calculate the half-bridge transformer
primary turns ≈ 40, using formula N(prim) = (Vin(nomi) * 0.5 * 10^8)/(4*fs*Bmax*Ae).

where Vin(nomi) = 311vdc
fs = 50KHz
Bmax = 1500 mT
Ae = 1.3 cm-sq.
Duty cycle = 0.98

with N(sec) ≈ 14 turns for 22 volt output Vsec = 22volt
& N(auxiliary) = 11 turns for 18volt.

Is this calculation correct? Read more

Microcontroller affected by ripple from BLDC motor –  I am driving BLDC motor(1kw) using STM32f1 microcontroller and Keil micro vision software as a compiler. While running motor on no load condition the motor runs good and the sensing sensor values, analog values, measuring rpm, etc which are all work good. On load condition the motor runs fine, but the waveforms of MOSFET gate and power supply of microcontroller ripples a lot. Read more

Class D amplifier simulation – I’m actually playing with LTspice to implement a class D amplifier. Below is a capture of the schematic and simulation results. Can someone explain to me why I cannot get an oscillation of +/- 15V at R1, instead of +/- 2V on the plotted area? Read more

Capacitors in input voltage circuit – Why are capacitors connected right before and after the reverse polarity protection Schottky diode in the input voltage circuit? What is the use of capacitors in this case? And if I supply 20volts input, how much voltage should be outcome before and after the reverse polarity diode? Read more

Protecting SMPS against mains transients – Obviously, the surge module has to go upstream of the AC mains filter in an SMPS. As such, would you agree that when the 1100v of “residual voltage” hits the AC input LC filter of the SMPS, then the voltage at the output of the diode bridge will actually be 2200V? We are trying to protect against this and believe that a TVS after the bridge rectifier is the way, would you agree? Read more