| In recent years, electronic technology has been developed rapidly and widely. It applied to various areas of the power industry and has brought many benefits to the development of electric power industry. With the development of power electronics industry, the requirements of electronic instruments and equipment are also higher and higher. Both performance and functionality should be safer and more reliable, more complete, and the volume and weight should be respectively smaller and lighter, so this requires us to adopt soft switch to meet these requirements. Currently, soft-switching power supply has been well developed and made great progress, it has many of advantages, greatly reduced the space and weight of power electronic devices, promoted the smaller, lightweight development of high-tech products.Soft switching circuit of resonant type switching converter solved the problem of low efficiency of traditional hard switching effectively, has got the attention and favor of the vast number of researchers. Now, LLC resonant converter especially has got more concerns.It has a good voltage regulation and zero-voltage characteristics of the opening of the switch, the characteristics of zero-current switching rectifier, determines its wide application in the power system. It has a power supply topology consistent with the direction of development, now its optimization has become a competing research. Study of LLC resonant converter is of great significance. LLC resonant converter topology is consistent with the development direction of power and has good voltage characteristics of the MOSFET driver and can achieve ZVS (zero voltage available) and the secondary side rectifier diode ZCS (zero-current turnoff) in the load range.The main content of this article is the LLC resonant converter in smart charger application and digital implementation. The traditional charging technology commonly used constant current charging, constant voltage charging, as well as voltage limiting charging and current limiting charging. Intelligent charging technology came into being, improve the quality of the charge, help extend battery life. This paper will apply to the LLC resonant converter intelligent charging technology, LLC resonant charging machine saved energy and charging time, greatly improved the charging efficiency and charging quality, and extended battery life.Firstly, we analyzed and discussed the working principle of LLC resonant converter and then modeled its mathematical model through the base frequency component method, gived the fundamental frequency of the LLC resonant converter equivalent model. Analysis of the influence of different parameters of LLC resonant converter gain and the parameters of the LLC resonant converter design flow solutions were given. On this basis, under PSIM9.0 environment simulation, verification using a closed-loop voltage and current control loop system performance under different load conditions, the steady-state and dynamic control performance achieved good results,proved LLC resonant converter control algorithm is correct.On the basis of the full simulation, LLC resonant 2000W conversion formula car charger was designed and produced. The battery voltage is 60V, output current is 30A, STM32F302CB-ARM microcontroller was adopted as a control chip to achieve a digital regulation and control LLC Charger and solve the LLC converter system gain with load change issues. It achieved good steady-state and dynamic performance, the performance was significantly better than traditional fixed parameter control hardware regulators. Experimental results show that under different load circumstances beyond its control performance and control precision can meet the design requirements. |
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