Hybrid vehicles (HEV) and electric vehicle (EV) power electronics are designed to supply electrical energy from a high voltage battery (400V/600) to a low voltage battery (12V) in normal operating mode. In addition, these automotive power electronic components must be capable of bidirectional DC/DC conversion so that in an emergency, when the HEV/EV needs to initiate boost, the low voltage battery powers the high voltage battery. In other words, this bidirectional design will require a buck mode to cause the voltage to drop, and a boost mode that re-energizes the voltage.
Design considerations
An ideal topology for the buck mode converter stage (400V to 12V) is Phase Shift Full Bridge (PSFB). This topology enables zero voltage switching (ZVS) of four electronic switches on the primary side of the isolation transformer and zero voltage switching of the diode rectifier (or MOSFET switch) on the secondary side for lower switching losses. In order to achieve optimum performance for low output voltage and / or high output current ratings, synchronous rectification is required on the secondary side to eliminate diode rectification losses.
Different operating modes can be utilized to control the PSFB power stage, such as voltage mode control (VMC), average current mode control (ACMC), or peak current mode control (PCMC). To avoid control circuit redesign due to power stage sensing circuit variations, it is best to consider using a high performance digital microcontroller.
TI's C2000TM 32-bit microcontrollers (MCUs) are specifically designed for digital power applications. The C2000 PiccoloTM TMS320F28035 MCU contains sufficient CPU processing power to run advanced control algorithms while providing flexible pulse width modulation (PWM) for advanced switching modes.
For boost mode converter stages, a synchronous rectifier switch can be used as a push-pull switch. The buck mode inductor can be used as a current source in this mode, making this topology a current-fed push-pull converter.
These control algorithms can be implemented on a single C2000 TMS320F2803x MCU. Through the feedback signal and PWM output, the TMS320F2803x MCU can interoperate with the power stage and can be placed on the low side.
Provides TI Design with all hardware & schematics
The bidirectional 400V-12V DC/DC converter TI Design uses the method described above. The four MOSFET switches (Q1 to Q4) form a full bridge on the high voltage side of the isolation transformer, while the two MOSFET switches (Q5 to Q6) are located on the center tapped low side. These switches operate as a synchronous rectifier in buck mode and as a push-pull switch in boost mode.
Controlling this system in different operating modes requires complex PWM waveforms and fast closed loop calculations. This implementation leverages features on the TMS320F2803x MCU, such as advanced PWM peripherals, a high-speed 12-bit ADC, and an integrated analog comparator that supports DAC and slope compensation.
System features include:
Bus voltage range from 200VDC to 400VDC
9 VDC to 13.5 VDC LV bus voltage range
300W rated output operation in either direction
Current rating of 33A on the LV bus and 1.8A rated current on the HV bus
Seamless on-demand instant conversion between buck mode and boost mode
Phase-shifted full bridge running in buck mode
Current feed type push-pull operation running in boost mode
100KHz PWM switch
Output inductor current VMC and ACMC
Multiple SR switch system configurations
Fault protection: overcurrent, undervoltage and overvoltage
Start design work with this bidirectional DC/DC converter. For additional information, please see the full demo here.
1080P Home Projector-1080P high-definition picture presentation, immersive experience, leisure and entertainment, enjoy games, videos, TV series, photos, sports, UEFA Champions League, etc. Mini Portable Projector, small and light, to carry and use, environmentally friendly micro LED flat light source design extremely long life
1080P Home Projector,Home Cinema Projectors,Projector For Room,1080p hd projector,1080p home cinema projector
Shenzhen Happybate Trading Co.,LTD , https://www.happybateprojector.com