单相并离网光伏逆变器设计与实现

Design and Implementation of Single-phase Parallel Off-grid Photovoltaic Inverter

本文以单片机为基础,设计了一款小功率单相光伏逆变器。该逆变器的输入为12V的光伏电池组,其逆变输出为24V、50Hz的标准正弦波交流电。该逆变器采用Boost升压和全桥逆变两级变换,在控制电路上,前级Boost升压电路采用UC3843芯片控制,准闭环稳压反馈;逆变部分采用驱动芯片TLP250高速光耦对全桥逆变进行隔离控制,采用单片机IAP15F2K61S2产生SPWM波并且对其的死区、时序控制,后级输出电压采用小型工频变压器进行采样反馈,再由单片机IAP15F2K61S2的ADC稳压形成双重反馈环节,增加了光伏逆变器的稳定性;后级输出电流采用ACS712芯片进行采样反馈,实现过载和短路保护。利用单片机IAP15F2K61S2的内部资源实现光伏电池组输入电压过压/欠压保护、过热保护等多重保护功能电路,增强了该逆变器的可靠性和安全性。利用LCD1602液晶显示屏和声光报警电路实现整机工况显示、故障显示及报警。

Based on single-chip computer, this paper designs a low-power single-phase photovoltaic inverter. The input of the inverter is 12V photovoltaic battery pack, and the output of the inverter is 24V, 50Hz standard sinusoidal AC. In the control circuit, the front Boost boost circuit is controlled by UC3843 chip with quasi-closed-loop voltage stabilization feedback;in the inverter part, the driver chip TLP250 high-speed optocoupler is used to isolate the whole bridge inverters, and the single chip IAP15F2K61S2 is used to generate SPWM wave and its dead zone. , timing control, the output voltage of the later stage is sampled and fed back by a small power frequency transformer, and then the ADC of the single chip iap15f2k61s2 is stabilized to form a double feedback link, which increases the stability of the photovoltaic inverter;the output current of the later stage is sampled and fed back by acs712 chip to achieve overload and short circuit protection. Using the internal resources of single chip IAP15F2K61S2, the multi-functional protection circuits such as input voltage overvoltage/ undervoltage protection and overheat protection for photovoltaic battery pack are realized, which enhances the reliability and safety of the inverter. LCD1602 LCD screen and acousto-optic alarm circuit are used to realize the whole machine working condition display, fault display and alarm.