Based On The Dsp2812 Pv Inverter Research And Design

The research on renewable energy and their applications have become more and more important due to the global energy crisis and environmental pollution. As one of the abundant clear energy, solar energy is the perfect substitute one. So the research on photovoltaic system and its application are vital. In the photovoltaic system, the DC/AC inverter is one of the pivotal parts, because it determines the stability and loading ability of the whole system.The off-grid PV inverter was researched completely from the following aspects in this thesis:1. The theory of photovoltaic inverter was analyzed from several points such as PWM fundamental principle, modulation mode, control technique, waveform generation. Comparing with other methods, the dual-close-loop negative feedback control mode was used. This mode makes output power quality better.2. Hardware design, including the designs for power inverting circuit, master control circuit, auxiliary power circuit, signal acquisition and processing circuit, communication interface circuit and so on. The high frequency inverting method, i.e. the boost voltage-rise and single-phase bridge inverting, was used to carry out power conversion. This method doesn't need any more transformers. Therefore the inverter has the features such as small size, less weight and high inversing efficiency. TI's DSP 2812 was taken as the core chip in master control circuit. The digital control system was designed so that its hardware circuit was simple and many complicated algorithms can be realized.3. Software programming. The software is divided into five subprograms including main program, SPWM subprogram, interface subprogram, communication subprogram, signal acquisition and processing subprogram. Three work modes of the inverter, i.e. normal mode, administrator mode and sleep mode, have been put forward firstly. The normal mode and sleep mode can be transferred automatically. Besides, the power modules can be switched off by software to provide with over-voltage and under-voltage protection for input and overload, short-circuit protection for output. As a result, no circuit breaker or fuse is necessary.4. Prototype development and experiment research. One prototype was developed and researched experimentally. The test results verified the accuracy and practicality of the design.