FULL BRIDGE LLC-CONVERTER USING PWM MODULATION
Abstract
Vehicles became the most essential parts of human life. They make lives easier as well as become a reason for pollution. Because conventional vehicles use gasoline, diesel, natural gas or petrol, They release carbon dioxide, nitrogen oxides and other harmful components causing pollution. So electric vehicles are proposed as the better alternative. Many researchers worked on different properties of electrical vehicles(EVs) like battery types, charger infrastructure etc. This FULL BRIDGE LLC-CONVERTER USING PWM MODULATION project focuses on working with Off-board chargers(OBC) which electric vehicles get charged. An LLC converter is used with a control strategy of Pulse Frequency Modulation(PFM) and Pulse Width Modulation(PWM) to get high output power from OBCs. The OBC circuit design is simulated using Matlab Simulink software.
Code Description & Execution of FULL BRIDGE LLC-CONVERTER USING PWM MODULATION
Algorithm Description
Fig: Structure of Off-Board Charger
High voltage batteries are utilized for the working of electrical vehicles. These electrical vehicle chargers have high power requirements, so an interleaved LLC converter is used in these off-board chargers. The off-board chargers include an EMI filter and a two-stage converter. The converter consists of a converter which converts the alternating current to direct current and another that further converts the direct current to the appropriate level. The AC/DC converter had a Power Factor Correction (PFC) module. The PFC is capable of isolating harmonic pollution from the grid and supplying direct voltage to the next module. The DC-DC converter is used to control complex load conditions and its design impact the off-board chargers the most. For this design of DC/DC converter, LLC topology is chosen because of its low EMI, high efficiency, wide voltage range and high power density. The LLC converters use a hybrid control strategy of power frequency modulation (PFM) and power width modulation (PWM) to get high output power. The LLC converter is designed with an interleaved parallel topology, making it suitable for use as a high-voltage off-board charger. The LLC topology reduces voltage stress and current stress.
Fig: Schematic diagram of LLC converter
There is difficulty with these off-board chargers in selecting resonant tank parameters. The designing of a resonant tank is difficult due to the rise in temperature and inductor saturation. For the designing purpose a digital power supply is used and for developing the OBC, a laboratory prototype with an output voltage of range 40-110 V and a maximum output power of 20kw is designed to verify the parameters of the LLC converter. The resonance frequency and the switching frequency range are 153 khz and 100-250 KHz, the rated output voltage and the rated output current are 80v and 200A.
MODEL DESCRIPTION of FULL BRIDGE LLC-CONVERTER USING PWM MODULATION
Steps to Execute the Code
- Download the zip file and unzip it
- Open matlab and click on simulink icon on home tab
3. Click on open when the following window pops up
4. A window pops up from which select the required file and click on open
5. Once the file is opened, click on run which is in the simulate tab.
Results of FULL BRIDGE LLC-CONVERTER USING PWM MODULATION:
- Once the simulation is ready click on scope to view the results.
2. These are the results for this simulation. Each different scope has different output because their functionality is different.
Issues Faced
- The above model is designed and developed in MATLAB 2019b version and model runs in 2019b version of MATLAB above , if you run in other versions of MATLAB you will get error
Reference:
Contact details:
All the required data has been provided over here. Please feel free to contact me for model weights and if you face any issues.