离网型光伏逆变器的研究与设计
发布时间：2018-07-29 18:02
【摘要】：在能源过度消耗和环境日趋恶化的当代,太阳能无疑是缓解能源危机最有价值的一种新能源,而逆变器在光伏发电系统中发挥着重要作用。本文将离网型光伏逆变器作为研究对象,深入研究了光伏逆变器的关键技术,设计出一台算法精确、性能优良的离网型光伏逆变器样机。逆变器分为软硬件两部分,硬件电路采用“推挽逆变+滤波整流+全桥逆变”结构,软件控制算法通过数字信号处理器实现。在推挽电路的开关器件上设计了齐纳吸收电路,解决了由于变压器漏感和导线寄生电感的存在,在功率器件快速开关时产生过压损害开关器件的问题,增强了功率器件的可靠性;前级电路设计了环路补偿电路,当负载突变或者直流电源波动时,环路补偿电路可以迅速稳定输出电压,提高了逆变器的稳定性和动态性能;全桥逆变电路上设计了RCD吸收电路,降低功率器件的应力和功率器件开关时刻产生的EMI,同时也起到软开关效果,减小开关损耗,提高逆变器的效率。通过数字式控制方式产生逆变器的双极性SPWM波驱动信号,使控制系统具有更高的精确度,更容易实现的高性能算法,简化了电路的复杂度,提高了整机功率密度,研究了SPWM波的生成算法,编写了相关软件代码。离网型光伏逆变器样机额定功率为500W,输出交流电压的频率为50Hz,有效值为225V,输出电压谐波含量小于5%。当负载为300W时,整机效率达到85%,缓冲电路可以有效的限制过冲电压,增强开关管的可靠性,温度达到50℃时,温控风扇自动开启,具有良好的保护功能,符合预期设计指标。
[Abstract]:In the era of excessive energy consumption and worsening environment, solar energy is undoubtedly the most valuable new energy to alleviate the energy crisis, and inverter plays an important role in photovoltaic power generation system. In this paper, the off-grid photovoltaic inverter is taken as the research object, the key technology of the photovoltaic inverter is deeply studied, and a prototype of the off-grid photovoltaic inverter with accurate algorithm and excellent performance is designed. The inverter is divided into two parts, the hardware circuit adopts the structure of "push-pull inverter filter rectifier full-bridge inverter", and the software control algorithm is realized by digital signal processor. Zener absorption circuit is designed on the switch device of push-pull circuit, which solves the problem of overvoltage damage switch device when power device switch quickly because of the existence of transformer leakage inductance and conductor parasitic inductance. The reliability of the power device is enhanced, the loop compensation circuit is designed in the front circuit, the loop compensation circuit can stabilize the output voltage rapidly and improve the stability and dynamic performance of the inverter when the load changes or the DC power supply fluctuates. The full-bridge inverter circuit is designed to reduce the stress of the power device and the switching time of the power device. At the same time, it also plays a soft switching effect, reduces the switching loss and improves the efficiency of the inverter. The bipolar SPWM wave driving signal of inverter is generated by digital control mode, which makes the control system have higher accuracy and higher performance algorithm, which simplifies the complexity of circuit and improves the power density of the whole machine. The generation algorithm of SPWM wave is studied, and the relevant software codes are written. The prototype of off-grid photovoltaic inverter has a rated power of 500W, a frequency of 50Hz output voltage, a effective value of 225V, and a harmonic content of less than 5W output voltage. When the load is 300W, the efficiency of the whole machine reaches 85. The buffer circuit can effectively limit the overshoot voltage and enhance the reliability of the switch tube. When the temperature reaches 50 鈩，
本文编号：2153546
[Abstract]:In the era of excessive energy consumption and worsening environment, solar energy is undoubtedly the most valuable new energy to alleviate the energy crisis, and inverter plays an important role in photovoltaic power generation system. In this paper, the off-grid photovoltaic inverter is taken as the research object, the key technology of the photovoltaic inverter is deeply studied, and a prototype of the off-grid photovoltaic inverter with accurate algorithm and excellent performance is designed. The inverter is divided into two parts, the hardware circuit adopts the structure of "push-pull inverter filter rectifier full-bridge inverter", and the software control algorithm is realized by digital signal processor. Zener absorption circuit is designed on the switch device of push-pull circuit, which solves the problem of overvoltage damage switch device when power device switch quickly because of the existence of transformer leakage inductance and conductor parasitic inductance. The reliability of the power device is enhanced, the loop compensation circuit is designed in the front circuit, the loop compensation circuit can stabilize the output voltage rapidly and improve the stability and dynamic performance of the inverter when the load changes or the DC power supply fluctuates. The full-bridge inverter circuit is designed to reduce the stress of the power device and the switching time of the power device. At the same time, it also plays a soft switching effect, reduces the switching loss and improves the efficiency of the inverter. The bipolar SPWM wave driving signal of inverter is generated by digital control mode, which makes the control system have higher accuracy and higher performance algorithm, which simplifies the complexity of circuit and improves the power density of the whole machine. The generation algorithm of SPWM wave is studied, and the relevant software codes are written. The prototype of off-grid photovoltaic inverter has a rated power of 500W, a frequency of 50Hz output voltage, a effective value of 225V, and a harmonic content of less than 5W output voltage. When the load is 300W, the efficiency of the whole machine reaches 85. The buffer circuit can effectively limit the overshoot voltage and enhance the reliability of the switch tube. When the temperature reaches 50 鈩，
本文编号：2153546
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