【摘要】：在能源過(guò)度消耗和環(huán)境日趨惡化的當(dāng)代,太陽(yáng)能無(wú)疑是緩解能源危機(jī)最有價(jià)值的一種新能源,而逆變器在光伏發(fā)電系統(tǒng)中發(fā)揮著重要作用。本文將離網(wǎng)型光伏逆變器作為研究對(duì)象,深入研究了光伏逆變器的關(guān)鍵技術(shù),設(shè)計(jì)出一臺(tái)算法精確、性能優(yōu)良的離網(wǎng)型光伏逆變器樣機(jī)。逆變器分為軟硬件兩部分,硬件電路采用“推挽逆變+濾波整流+全橋逆變”結(jié)構(gòu),軟件控制算法通過(guò)數(shù)字信號(hào)處理器實(shí)現(xiàn)。在推挽電路的開(kāi)關(guān)器件上設(shè)計(jì)了齊納吸收電路,解決了由于變壓器漏感和導(dǎo)線寄生電感的存在,在功率器件快速開(kāi)關(guān)時(shí)產(chǎn)生過(guò)壓損害開(kāi)關(guān)器件的問(wèn)題,增強(qiáng)了功率器件的可靠性;前級(jí)電路設(shè)計(jì)了環(huán)路補(bǔ)償電路,當(dāng)負(fù)載突變或者直流電源波動(dòng)時(shí),環(huán)路補(bǔ)償電路可以迅速穩(wěn)定輸出電壓,提高了逆變器的穩(wěn)定性和動(dòng)態(tài)性能;全橋逆變電路上設(shè)計(jì)了RCD吸收電路,降低功率器件的應(yīng)力和功率器件開(kāi)關(guān)時(shí)刻產(chǎn)生的EMI,同時(shí)也起到軟開(kāi)關(guān)效果,減小開(kāi)關(guān)損耗,提高逆變器的效率。通過(guò)數(shù)字式控制方式產(chǎn)生逆變器的雙極性SPWM波驅(qū)動(dòng)信號(hào),使控制系統(tǒng)具有更高的精確度,更容易實(shí)現(xiàn)的高性能算法,簡(jiǎn)化了電路的復(fù)雜度,提高了整機(jī)功率密度,研究了SPWM波的生成算法,編寫(xiě)了相關(guān)軟件代碼。離網(wǎng)型光伏逆變器樣機(jī)額定功率為500W,輸出交流電壓的頻率為50Hz,有效值為225V,輸出電壓諧波含量小于5%。當(dāng)負(fù)載為300W時(shí),整機(jī)效率達(dá)到85%,緩沖電路可以有效的限制過(guò)沖電壓,增強(qiáng)開(kāi)關(guān)管的可靠性,溫度達(dá)到50℃時(shí),溫控風(fēng)扇自動(dòng)開(kāi)啟,具有良好的保護(hù)功能,符合預(yù)期設(shè)計(jì)指標(biāo)。
[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，

本文編號(hào)：2153546