I've been trying to create an isolated DC/DC converter for cell balancing but I can't seem to get the topology quite right.
In the topology shown in the picture, the cell is on the left and the battery on the right.
The MOSFET with the tag "C1" shorts the inductor, increasing its current. Then it turns off and the inductor current forces the diode to conduct, thus charging the capacitor and increasing the current in the primary of the transformer.
When the MOSFET turns off again, the capacitor would take the decreasing current from the transformer. Since the current in the transformer is always going up and down (but always with the same polarity), this would create magnetic flux in the core of the transformer and transfer energy to the secondary winding, charging the main battery.
The FET with the "BoostON" tag would only turn on when the converter is turned on, and it would be always conducting. When the converter stops the energy transfer between cell and battery, this transistor would be turned off. This is to avoid shorting the cell through the transformer and boost diode when the converter is not working.
So, are there any flaws in this topology? Are there any reasons why this would just outright fail, or would it actually work as intended?
This is just a typical boost converter with an extra transformer and a diode on the secondary side. The bigger circle in the transformer indicates the primary side. The transformer used would be this one, with a 1:4 turn ratio. The objective is to implement PI/PID current control to get an average inductor current of 3 A. The reason I want to avoid the typical fly-back topology is because of the control issues that may arise. The switching frequency is going to be 30kHz, and the inductor used would be somewhere around 70~90uH (calculated for the normal boost topology). The capacitance value in the image is random. Simulations show that the circuit should work as intended.