Hello,
As part of a course I am taking I am tasked with designing a Bi-directional DC-DC converter which takes supplies energy from a battery at ~11 volts and delivers energy at 5 V (2 Amps), 12 V (3 A), and allow for charge of the battery at 20 V (3 A). The basic layout is follows but currently I am only tasked with developing the converter portion.
For the purposes of the project we are allowed two control signals and are designing within LTSpice - We are provided an example of a boost converter (which cannot satisfy the requirements of the project due to its inability to reduce voltage from input to output) that I have copied below for reference.
The only unusual components here are the blocks U5 and U3 - U5 essentially just an unregulated DC-DC converter which acts as a power supply for high side MOSFETs and U3 is a dead time circuit for generating complimentary signals from the PWM.
My approach to this problem was to create a synchronous buck+boost converter to address the project requirements - I started using ideal switches for the buck and boost stages individually - before moving to a combined circuit resembling a two-switch implementation of the buck+boost topology - before finally attempting to implement a fully synchronous buck+boost converter. I was able to achieve the buck and boost outputs (5 V and 20 V respectively) in the two switch implementation but transitioning to a synchronous converter everything has gone awry.
My current circuit is below along with the parameters in/out/control1/control2:
And the Vout waveform is shown below:
I think the "bones" of the converter are correct in terms of component location and control signal operation - but the gate drivers are not properly implemented and I am at a loss for how to correct them. Any help would be greatly appreciated!
(btw we are not allowed to use independent/dependent sources, ideal switches/transformers, switching controllers, or any other IC/chips and eventually the inductor I used will need to be replaced with a saturating inductor model similar to the boost example - I have attached the project description below for reference along with my current LTSpice schematic)
As part of a course I am taking I am tasked with designing a Bi-directional DC-DC converter which takes supplies energy from a battery at ~11 volts and delivers energy at 5 V (2 Amps), 12 V (3 A), and allow for charge of the battery at 20 V (3 A). The basic layout is follows but currently I am only tasked with developing the converter portion.
For the purposes of the project we are allowed two control signals and are designing within LTSpice - We are provided an example of a boost converter (which cannot satisfy the requirements of the project due to its inability to reduce voltage from input to output) that I have copied below for reference.
The only unusual components here are the blocks U5 and U3 - U5 essentially just an unregulated DC-DC converter which acts as a power supply for high side MOSFETs and U3 is a dead time circuit for generating complimentary signals from the PWM.
My approach to this problem was to create a synchronous buck+boost converter to address the project requirements - I started using ideal switches for the buck and boost stages individually - before moving to a combined circuit resembling a two-switch implementation of the buck+boost topology - before finally attempting to implement a fully synchronous buck+boost converter. I was able to achieve the buck and boost outputs (5 V and 20 V respectively) in the two switch implementation but transitioning to a synchronous converter everything has gone awry.
My current circuit is below along with the parameters in/out/control1/control2:
And the Vout waveform is shown below:
I think the "bones" of the converter are correct in terms of component location and control signal operation - but the gate drivers are not properly implemented and I am at a loss for how to correct them. Any help would be greatly appreciated!
(btw we are not allowed to use independent/dependent sources, ideal switches/transformers, switching controllers, or any other IC/chips and eventually the inductor I used will need to be replaced with a saturating inductor model similar to the boost example - I have attached the project description below for reference along with my current LTSpice schematic)
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