In two-stage Cascaded Boost converter, there are two switches, but one has low voltage + high current while the second has high voltage + low current. In Quadratic converter, the single switch has high voltage (highest voltage) + high current rating (sum of two switch currents), making the MOSFET more expensive and lossy.
In hard switching, the cascade connection of two boost converters can show a higher efficiency than the conventional quadratic boost converter because the diode replacing the MOSFET in the input stage of the quadratic boost must support high voltage and high current. However, by using SiC in MOSFET and diodes, the simplicity of the quadratic boost converter becomes attractive. The dynamical behavior at the same operational conditions remains more or less the same.
From other point of view, in the cascade connection of two boost converter which have two controlled switches, we have two degree freedoms, and then, it is possible to use two different duty cycle to accomplish some control objectives or find a maximization of the efficiency.
The voltage gain of quadratic boost converter with modified voltage lift cell is highest and the switch voltage stress of quadratic boost converter with modified voltage lift cell is lowest . This is making the difference.
In hard switching, the cascade connection of two boost converters can show a higher efficiency than the conventional quadratic boost converter because the diode replacing the MOSFET in the input stage of the quadratic boost must support high voltage and high current. However, by using SiC in MOSFET and diodes, the simplicity of the quadratic boost converter becomes attractive. The dynamical behavior at the same operational conditions remains more or less the same.
From other point of view, in the cascade connection of two boost converter which have two controlled switches, we have two degree freedoms, and then, it is possible to use two different duty cycle to accomplish some control objectives or find a maximization of the efficiency.
Adly, in hard switched Quadratic converter, how can efficiency be higher that cascaded boost as one switching path in former is through a diode and MOSFET together in series, having total higher voltage drop and hence higher power dissipation ?
Adly, I have my doubts. Can you show us what is the circuit you are referring to as "quadratic converter" where the power processing is different from that if I have two cascaded boost cells operating in synchronism ? I believe you have also two distinct stages (two separate sets of energy storage inductors & capacitors) in your "quadratic converter" but only a common switch.
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