本文選題：集中變頻 + 電流源型變頻器�。� 參考：《中國礦業(yè)大學》2015年碩士論文

【摘要】：目前,市場上存在大量變頻傳動產品,它們采用不同功率開關器件拓撲結構和控制策略各具特色,其中,電流源型變頻器基于其結構以及控制的優(yōu)越性,在高壓大功率場合傳動領域獲得廣泛應用。針對煤礦井下惡劣環(huán)境以及防爆變頻器設計的復雜性,往往選用長距離變頻傳輸系統(tǒng),但同時由長距離帶來的電機端過電壓和傳導干擾等負面影響也隨功率和開關頻率的提高變得越來越嚴重。本文基于煤礦井下工作面地面集中變頻系統(tǒng)研發(fā)項目,結合電流源型變頻器控制優(yōu)越性,針對電流源型變頻器的長距離傳輸系統(tǒng)帶來的負面影響,主要展開了以下工作。首先,分析了系統(tǒng)結構特點,以電流源型逆變器為研究對象,對電流源型逆變器調制策略進行深入研究,重點研究了兩種調制策略:梯形波脈寬調制(TPWM)、電流空間矢量脈寬調制(SVPWM),在MATLAB軟件中分別建立仿真模型,通過改變調制波頻率和直流電流大小實現了逆變器輸出電流頻率和幅值的控制,并對兩種調制算法的特點進行了對比分析。其次,基于傳輸線理論分析了電壓、電流反射現象及電動機端過高電壓的產生機理,分析結果表明,負載與電纜阻抗不匹配是電機端過電壓形成的主要原因;針對電流源型逆變器共模電壓進行定義,公式推導分析PWM變頻器中共模電壓的產生機理和表達式,建立共模等效電路,分析了逆變器九種開關狀態(tài)分別對應的共模電壓,建立仿真模型仿真分析了逆變器輸出的共模電壓;為進一步分析,建立適用于長距離電纜系統(tǒng)分析的高頻電纜模型和高頻電機模型,通過實驗計算得到模型各參數,驗證了模型的有效性。再次,結合MATLAB與PSPice仿真軟件建立系統(tǒng)仿真模型,對比電壓脈沖仿真分析了電流脈沖反射規(guī)律,結合兩種調制策略仿真分析了電流PWM波對電機端電壓的影響,結果表明:電流源型逆變器輸出不受電纜長度限制,建立電流源型變頻器實驗平臺,采用SVPWM調制策略進行了實驗驗證。最后,針對共模電壓產生規(guī)律對共模電壓的抑制策略進行研究,從硬件和軟件兩個方面進行分析,硬件方面主要通過一體化電抗器結構和輸入輸出電容連接結構減少共模電壓對系統(tǒng)的影響,軟件方面,基于SVPWM調制策略重點研究了三種非零矢量抑制策略和一種三相四橋臂抑制策略,在MATLAB中分別建立仿真模型驗證了幾種抑制策略的有效性并進行了對比分析。
[Abstract]:At present, there are a large number of variable-frequency drive products in the market, which adopt different topology and control strategy of different power switch devices. Among them, the current-source inverter is based on its structure and advantages of control. It is widely used in the field of high-voltage and high-power transmission. In view of the complexity of the design of the bad environment and explosion-proof frequency converter in coal mine, the long distance frequency conversion transmission system is often used. But at the same time, the negative effects such as overvoltage and conduction interference brought by long distance also become more and more serious with the increase of power and switching frequency. Based on the research and development project of ground centralized frequency conversion system in underground working face of coal mine, combined with the control superiority of current source converter, the paper mainly carried out the following work in view of the negative influence brought by the long distance transmission system of current source converter. Firstly, the characteristics of the system structure are analyzed, and the modulation strategy of the current-source inverter is deeply studied, taking the current-source inverter as the research object. Two modulation strategies: trapezoidal pulse width modulation (TPWM) and current space vector pulse width modulation (SVPWM) are studied. The output current frequency and amplitude of the inverter are controlled by changing the modulation frequency and DC current, and the characteristics of the two modulation algorithms are compared and analyzed. Secondly, based on the transmission line theory, the mechanism of voltage, current reflection and over-high voltage at motor terminal is analyzed. The results show that the mismatch between load and cable impedance is the main reason for the formation of over-voltage at motor end. According to the definition of common-mode voltage of current-source inverter, this paper deduces and analyzes the mechanism and expression of common-mode voltage of PWM inverter, establishes the common-mode equivalent circuit, and analyzes the common-mode voltage corresponding to nine switching states of inverter. The common mode voltage of inverter output is simulated and analyzed by the simulation model. For further analysis, the high frequency cable model and the high frequency motor model suitable for the analysis of long distance cable system are established, and the parameters of the model are obtained by experimental calculation. The validity of the model is verified. Thirdly, with MATLAB and PSPice simulation software to establish the system simulation model, compared with the voltage pulse simulation analysis of the current pulse reflection law, combined with two modulation strategies to simulate the impact of current PWM wave on the motor terminal voltage. The results show that the output of current-source inverter is not limited by cable length. The experimental platform of current-source inverter is established and the SVPWM modulation strategy is used to verify the experiment. Finally, aiming at the common mode voltage generation rule, the common mode voltage suppression strategy is studied, and the hardware and software are analyzed. In the hardware aspect, the common mode voltage is reduced by the integrated reactor structure and the input and output capacitance connection structure. Based on SVPWM modulation strategy, three non-zero vector suppression strategies and one three-phase four-arm suppression strategy are studied. Simulation models are established in MATLAB to verify the effectiveness of several suppression strategies.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM921.51

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