The Circuit Research And Realization Of A Two-transistor Forward Smart Charger

At present, the battery is an important tool to use of clean energy. It has been widely used in many areas. So the type of battery is becoming more and more complex. At the same times, As the traditional charger of battery charging important tool is also facing great challenges. It has to adapt to different battery pack, complete fault protection, unattended charging, remotely modify the charging parameters and other functions. This kind of intelligent charger is demanded significantly.This paper aims to design and achieve a circuit system of intelligent charger with digital control technology and high-frequency switching technology. And the intelligent charger overcomes the traditional charger’s weaknesses, such as the imperfect protection, low energy efficiency, human duty charging and so on. Firstly, this paper proposes the design and functional parameters of intelligent charger according to the research background. Secondly, the paper has determined that the intelligent charger based on the TMS320F2812 type of TI’s DSP to achieve digital system control. While comparing the basic topology types of switching power supply, selection of secondary tandem two-transistor forward isolated DC / DC topology to be the intelligent charger’s power supply. And it analysiss the works of power supply topology. Their whole system scaffolding framework based on the above DSP control system and power supply topologies. Thirdly, the paper does a a detailed analysis to the electromagnetic machine compatible with the needs and sources of interference. And the paper proposes and designs the solutions of electromagnetic compatibility. Forthly, according to the design specifications, the paper has designed all hardware circuit of the intelligent charger. What’s more is the selection way of the parameters of the important power devices. Finally, on the building the platform, it does waveform analysis, function test, efficiency test, EMC test. Finally the feasibility of whole scheme is validated and it meets the expected design function and parameters.The final design of hardware circuit of the intelligent charger has be completed in this paper. And according to the system of intelligent charging machine prototype test results. The maximum system efficiency is 89%. The output voltage accuracy is 0.5%. The output current accuracy is 1%. The ways of communication are CAN and RS-485. It can remote charging parameter modification and draw the charging curve and record fault and other functions. The perfect protection can achieve unattended full charge. The experiments by EMC testing verify the reliability and stability of the intelligent charger.