基于SPWM混合调制的光伏并网逆变实践教学装置研制

Development of a Practical Teaching Device for Photovoltaic Grid Connected Inverter Based on SPWM Hybrid Modulation

为更好达到光伏并网逆变原理教学目标,基于模拟和数字控制技术研制一台通用光伏并网逆变实践教学装置。装置集成了DC/DC、DC/AC、通信和上位机显示等单元。利用SG3525为核心的升压电路和DSP TMS320F28335为核心的逆变电路作为教学装置的通用主电路,采用正弦脉宽调制(SPWM)单、双极性混合控制策略,完成课程中直流升压、逆变等多种实验。通过教学装置的操作、训练,显著提升学生对升压开关变换电路的原理、特性以及单相SPWM逆变电路的工作原理、波形分析的理解。

To enhance the achievement of teaching objectives in photovoltaic grid-connected inverter principles,this paper presents a universal photovoltaic grid-connected inverter practical teaching device based on simulation and digital control technology.The device integrates a DC-DC boost unit,a DC-AC full-bridge inverter unit,a communication unit,and an upper computer display unit.The teaching device’s universal main circuit is the boost circuit with SG3525 as the core and the inverter circuit with DSP TMS320F28335 as the core.It employs the sinusoidal pulse width modulation(SPWM)single and double polarity hybrid modulation control strategy,enables the completion of various experiments such as DC boost and inverter during the course.The teaching device significantly improves students’understanding of boost switching circuit principles and characteristics,as well as the working principle and waveform analysis of singlephase sinusoidal pulse width modulation(SPWM)inverter circuits.