Research On High Power ZVZCS Electric Vehicle Charging Power Supply Based On DSP&CPLD

With the continuous reduction of oil and other non-renewable energy and environmentpollution becoming increasingly serious, the development of energy-saving, environmentalfriendly and clean electric vehicles has become the trend of the automotive industry. Electricvehicle charging facilities are the foundation of the electric vehicle industry. Research ontechnical issues related to charge power supply has a significance on the electric car industry.Firstly, the developing status on the electric vehicle charge power supply and chargingtechnology development are described in this paper. In view of the defects of the existingcharging power supply, and according to the requirements and features of the charging powersupply design, a ZVZCS PWM full-bridge converter with passive clamp circuit phase shiftcontrol on the secondary side is selected. A simple equivalent circuit model is established, inaddition, the working process and soft switch implementation are analyzed in detail, and theimportant components parameters of main power circuit are determined.Secondly, the hardware and software design of charging power supply control systemare discussed in detail. With DSP for data acquisition and processing, CPLD is used tocomplete logic operation of the fault signal, so as to the respond to the fault information.Furthermore, a method of IGBT over-current grading protection is proposed in thispaper, and a method of half period protection is put forward, compared with the traditionalcycle protection，the current on the transformer primary side is more continuous，therefore,the slight bias of transformer is solved.In addition, the parallel technology of multi-single charging power supply is studiedbased on the aforementioned technology, a parallel control method avoiding light running isput forward as well. Besides, as the paralleling current technique is difficult to realize, a newdigital paralleling current plan based on CAN is presented in the paper.Finally, an experimental prototype is completed, and the debugging of the system andthe related experiments are conducted on the prototype.The experimental results show thatsoft switching of the charging power supply can be realized in full range, with multipleprotection function and efficiency up to96.5%. A multiple standalone paralleling scheme isadopted to avoid light load running, and the system efficiency of the whole machine canmaintain at90%or more, each single stream achieve good performance, and the accuracyof the paralleling current is within2%.