i am making bidirectional buck-boost converter. The schismatic of bidirectional buck boost converter is attached here.
Buck Mode = when PWM is applied to Q1 , it work as buck converter. when q1 is OFF D2 will conduct. Q1 and D2 work for Buck converter. power flow is forward.
Boost Mode= when PWM is applied to Q2, it work as boost converter. so Q2 and D1 work for Boost converter. power flow will be opposite. capacitor and load will be connected to V1 voltage side.
i am generating 5v PWM fron function generator and giving it to gate of MOSFET through Gate Driver IR2110. i am facing some problems that are listed below
1) during Boost Mode , when i only use low side MOSFET Q2 and D1 , i achieved 96% efficiency without connecting Q1 high side mosfet. whenever i connect Q1, its efficency goes down. Q1 was heated up. can you tell me what is problem. why Q1 was heated up? why it conducts. i applies its gate to gound. there are some pulses that turns on the Q1 mosfet. it should never turn on during Boost mode.
2) Similarly the case with Q2 , during buck mode. during boost mode , the gate of Q2 is grounded.