I have gone through some papers related to Bi-directional buck-boost converters. And trying to simulate the circuit with their specifications.
But got stuck with the switching signals of the auxiliary circuit.
Example Paper Title:"Family of Soft Switching Bidirectional Converters with Extended ZVS Range"
I think the pulses of the bidirectional dc_dc converter is totally depends upon the controller design. As per the question, bidirectional dc-dc converter operates for both buck and boost mode of operation. If you have a fixed reference voltage, then by comparing the fixed voltage with the generating voltage the pulses of the converter can be designed.
For an example if your reference voltage is 20V and the generating voltage is 10V. Then by comparing this we can get a positive voltage error. If this is positive, then the converter operates in boost mode and if this is negative then converter is operating in buck mode of operation. Now come to to your question.. After generating the voltage error, it is passed through a pi controller to generate signal. After generating the signal, by using a comparator like >=0 the switch s1 is on otherwise s2 is on. Likewise, we can generate pulses for that..
For better understanding.. You can read my published papers
Thanking you
Buddhadeva Sahoo
Buddhadeva Sahoo thank you for your reply Sir. I do understand the main circuit switching. But I am stuck with the auxiliary circuit switching part. I tried to simulate the above mentioned papers circuit. But couldn't.
Can you tell something about auxiliary circuit switching?
You mean auxilary switch. As per your design, I think you add an additional not gate to the regular signal. It generates an alternate signal to your auxilary circuit. I mean to say, when your general switch is on, your auxilary switch is off and vice versa. It is a simplest method. Hope you will get it
Sir, I have attached the circuit. i am referring to the auxiliary circuit used for ZVT/ZCT.
Dear Zubair
About the gate signal of the auxiliary switches, it is very simple to implement them. It is only required to turn on before the turn-on isntant of the main switch (with a proper dead time). Note in buck mode, the main switch is S1 and, Sa1 should be controlled, and in boost mode, the main swithc is S2 , and Sa2 should ve controlled. Not forget to add a seri diode with each auxiliary switch, since they should be unidirectional.
Please let me know about the simulation software that you utilize.
Mohammad Reza Mohammadi respected Author, I am using the Orcad PSPice 17.2.
But I got discontinuos current waveform when I used the auxiliary switch in the buck mode only[S1, Sa1]. I used a 6 ohm resistor as a load to receive 150 W at 30 V.
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