Development of a Practical Teaching Device for Photovoltaic Grid Connected Inverter Based on SPWM Hybrid Modulation
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 single-phase sinusoidal pulse width modulation(SPWM)inverter circuits.