改進(jìn)虛擬磁鏈觀測(cè)器的并網(wǎng)逆變器控制策略
郭茂松,王英
(大連交通大學(xué) 電氣信息學(xué)院,遼寧 大連 116028)
摘 要:為了改進(jìn)并網(wǎng)逆變器運(yùn)行的可靠性,提出一種鎖相環(huán)和改進(jìn)虛擬電網(wǎng)磁鏈估算相結(jié)合的并網(wǎng)控制策略。該方法是在低通濾波器取代純積分器的基礎(chǔ)上,采用兩個(gè)不同截止頻率和比例系數(shù)的低通濾波器,構(gòu)造磁鏈觀測(cè)器,結(jié)合鎖相環(huán)以提高虛擬磁鏈定向的準(zhǔn)確度,有效抑制電網(wǎng)諧波干擾。分析了三相并網(wǎng)逆變器基于同步旋轉(zhuǎn)坐標(biāo)系的數(shù)學(xué)模型,建立鎖相環(huán)和虛擬電網(wǎng)磁鏈相結(jié)合進(jìn)行定向的矢量控制系統(tǒng)。仿真實(shí)驗(yàn)結(jié)果表明,逆變器可輸出正弦度良好的逆變電流,提高了逆變器的工作穩(wěn)定性,從而驗(yàn)證了該方案的可行性和正確性。
關(guān)鍵詞:并網(wǎng)逆變器;磁鏈觀測(cè)器;鎖相環(huán);低通濾波器
中圖分類(lèi)號(hào):TM464 文獻(xiàn)標(biāo)識(shí)碼:A 文章編號(hào):1007-3175(2017)05-0010-05
Control Strategy of Grid-Connected Inverter for Improved Virtual Flux Observer
GUO Mao-song, WANG Ying
(School of Electronics and Information Engineering, Dalian Jiaotong University, Dalian 11 6028, China)
Abstract: In order to improve the reliability of grid-connected inverter, a way of phase locked loop (PLL) and an improved control strategy was proposed to improve the virtual flux linkage estimation. The low-pass filter was used to replace the pure integrator, with two different cut-off frequencies and proportional coefficients, combined with the PLL to improve the accuracy of the virtual flux orientation, effectively suppressing the harmonic interference.This paper analyzed the mathematical model of three-phase grid-connected inverter based on synchronous rotating coordinate system, and established a PLL and a virtual power grid flux linkage for the vector control system. The simulation results show that the sinusoidal output current of the three-phase grid-connected inverter is good, and the stability of the inverter is improved, which verifies the feasibility and correctness of the scheme.
Key words: grid-connected inverter; flux observer; phase locked loop; low-pass filter
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