本文選題：雙模式逆變器 + 不平衡電網(wǎng)�。� 參考：《北方工業(yè)大學(xué)》2017年碩士論文

【摘要】：運行于微電網(wǎng)下獨立和并網(wǎng)兩種模式的雙模式逆變器,難免會遇到電網(wǎng)三相電壓不平衡的狀況。三相電壓對稱度作為微電網(wǎng)電能質(zhì)量的重要指標(biāo),對于微電網(wǎng)的正常運行有著重要的影響。此外,在實際用戶的用電條件下,很容易因用戶的用電分配不均或外界引起的各種故障導(dǎo)致負(fù)荷側(cè)三相電壓不平衡情況。目前,電網(wǎng)和負(fù)載平衡下的逆變器控制已經(jīng)有了較為成熟的方法。比如離網(wǎng)運行時的恒壓恒頻Vf控制方法,還有并網(wǎng)時的恒功率PQ控制方法,此外還有下垂控制方法等。這些方法都是在三相電壓平衡的基礎(chǔ)上通過比例積分或者比例諧振等跟蹤調(diào)節(jié)方式進(jìn)行穩(wěn)定控制調(diào)節(jié)。然而,當(dāng)電壓發(fā)生三相不平衡的情況時,相對于三相平衡條件,會出現(xiàn)電壓的負(fù)序分量。目前的控制方法大都是建立在三相電壓對稱即只存在電壓正序而不存在負(fù)序分量的基礎(chǔ)上。如果存在電壓不平衡的情況而仍然采用只控制正序分量的方法,會導(dǎo)致輸出電壓和電流的畸變、諧波增大等問題,無論對負(fù)載還是逆變器都會有很大的影響。所以需要將不平衡電壓條件下的正序和負(fù)序電壓分量分離并提取出來分別進(jìn)行控制。其中使用的方法有濾波分離法、對稱分量法和延遲信號方法等。此外,對于并網(wǎng)系統(tǒng),還要考慮并網(wǎng)鎖相環(huán)的設(shè)計,由于負(fù)序分量的存在,如果采用常規(guī)的正序分量的鎖相環(huán)難免會出現(xiàn)鎖相失敗的情況,因此,本文研究了二階廣義積分、雙同步解耦鎖相環(huán)的方法用以在不平衡電網(wǎng)條件下的鎖相�；谏鲜龅恼�(fù)序分離和鎖相方法,本文采用了離網(wǎng)電壓電流正負(fù)序雙環(huán)控制法和并網(wǎng)瞬時功率控制及負(fù)序分量抑制方法,消除電壓電流畸變,減小輸出諧波,保持功率穩(wěn)定和效率的最大化以改善不平衡負(fù)載和電網(wǎng)環(huán)境對逆變器的影響。最后,結(jié)合各種帶載及并網(wǎng)的雙模式逆變器的拓?fù)浣Y(jié)構(gòu),基于Matlab/Simulink分別建立了并網(wǎng)和獨立情況下的仿真模型,并進(jìn)行了電網(wǎng)和負(fù)載不平衡條件下逆變器運行的仿真驗證。此外,本文還介紹了以DSP28335為控制核心的電路實驗平臺及對以上的理論和仿真進(jìn)行的實驗工作,仿真和實驗驗證了本文控制策略的正確和可行性。
[Abstract]:The two-mode inverter running in the microgrid with independent and grid-connected modes will inevitably encounter the unbalanced three-phase voltage.As an important index of power quality, three-phase voltage symmetry plays an important role in the normal operation of micro-grid.In addition, under the condition of actual users' electricity consumption, it is easy to cause unbalanced three-phase voltages on the load side because of the uneven distribution of electricity by the users or various kinds of faults caused by the outside world.At present, inverter control under power grid and load balance has been more mature.For example, the constant voltage and constant frequency VF control method, the constant power PQ control method and the droop control method are used in off-grid operation.These methods are based on the three-phase voltage balance through the proportion integral or proportional resonance tracking regulation to achieve stable control.However, when the voltage is unbalanced, the negative sequence component of the voltage will appear relative to the three-phase equilibrium condition.Most of the current control methods are based on the three-phase voltage symmetry, that is, there is only a positive voltage sequence and no negative sequence component.If the voltage is unbalanced and only the positive sequence component is controlled, the output voltage and current will be distorted and the harmonic will increase, which will have a great influence on both the load and the inverter.So it is necessary to separate and extract the positive sequence and negative sequence voltage components under unbalanced voltage and control them separately.The methods used are filter separation, symmetrical component method and delay signal method.The method of double synchronous decoupling PLL is used in the condition of unbalanced power grid.Maintain power stability and maximize efficiency to improve the impact of unbalanced load and grid environment on the inverter.Finally, combined with the topology of various dual-mode inverters with load and grid-connected, the grid-connected and independent simulation models are established based on Matlab/Simulink, and the simulation verification of inverter operation under the condition of power grid and load imbalance is carried out.In addition, this paper also introduces the circuit experiment platform with DSP28335 as the control core, and the experimental work of the above theory and simulation. The simulation and experiment verify the correctness and feasibility of the control strategy in this paper.
【學(xué)位授予單位】：北方工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM464;TM727

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 王明s，

本文編號：1732607