發(fā)布時間：2018-12-24 11:12

【摘要】：由于風電變流器運行工況越來越復雜,使得對風電系統(tǒng)可靠性要求也越來越高。功率器件結溫的波動是引起器件故障的主要因素,而器件結溫的波動是隨著風機輸出功率變化而變化。因此,跟隨風機輸出功率的變化,實時的調節(jié)器件結溫顯得十分有必要。目前,主要的結溫控制方式包括:以外部散熱或冷卻的方式來調節(jié)功率器件結溫的外部結溫控制和以控制功率器件損耗為基礎的內部結溫控制。前者主要是調節(jié)器件的平均結溫,對器件結溫的波動情況調節(jié)效果較差。由于開關頻率對功率器件的損耗影響較大,因此本文采用變開關頻率的內部結溫控制方式,來實現(xiàn)風機中功率器件結溫的調節(jié)來開展研究工作。為分析開關頻率對IGBT功率模塊損耗和結溫的影響情況,本文首先對三相并網逆變器IGBT功率模塊損耗進行了分析。針對傳統(tǒng)的三相逆變器功率器件損耗模型局限于SPWM調制策略、對器件結溫對損耗影響的分析不足等問題,本文推導了SVPWM調制下的三相并網逆變器功率器件損耗計算公式,該公式中引入了結溫反饋量,并根據(jù)功率器件用戶使用參數(shù),采用曲線擬合的方式對IGBT功率器件損耗進行計算,并分析了開關頻率對IGBT功率模塊損耗的影響,為變開關頻率調節(jié)結溫提供了理論依據(jù)。其次,由于開關頻率是影響IGBT功率模塊損耗的重要因素,為實現(xiàn)IGBT功率模塊結溫的有效控制,本文提出了一種實時變開關頻率的IGBT功率模塊結溫控制方法,通過建立風電變流器結溫預測模型提取變開關頻率結溫控制參數(shù),獲得了流過IGBT的電流、開關頻率、IGBT功率模塊結溫波動值的函數(shù)關系式,并通過仿真驗證了運用該函數(shù)關系式對IGBT功率模塊結溫進行控制的可行性。然后,為在數(shù)字電路中實現(xiàn)三相并網逆變器變開關頻率控制,本文提出了一種基于FPGA的變開關頻率實現(xiàn)方法,該方法根據(jù)FPGA自上而下的設計思路以及并行運行的特點,將整個控制模塊劃分為多個子模塊,每個子模塊相對獨立并行運行,通過VHDL語言編寫SVPWM算法模塊、Cordic算法模塊、三相鎖相環(huán)等子模塊的邏輯行為,并通過Modelsim軟件仿真驗證模塊的算法邏輯,從而驗證了SVPWM調制下三相逆變器變開關頻率的可行性。最后,搭建三相逆變器變開關結溫控制實驗平臺,以DSP作為采樣部分,FPGA作為控制核心,實現(xiàn)輸出電流變化時,開關頻率的變化情況對比。從而驗證了提出變開關頻率結溫控制方法的合理性以及可行性。
[Abstract]:Because of the more and more complex operating conditions of wind power converter, the reliability requirement of wind power system is becoming more and more high. The fluctuation of junction temperature of power device is the main factor that causes device fault, and the fluctuation of device junction temperature changes with the change of fan output power. Therefore, following the change of fan output power, it is necessary to adjust the device junction temperature in real time. At present, the main control methods of junction temperature include the external junction temperature control based on external heat dissipation or cooling and the internal junction temperature control based on the control of power device loss. The former mainly adjusts the average junction temperature of the device, and the effect on the fluctuation of the device junction temperature is poor. Because the switching frequency has a great influence on the loss of power devices, the internal junction temperature control mode with variable switching frequency is adopted in this paper to realize the adjustment of junction temperature of power devices in the fan to carry out the research work. In order to analyze the influence of switching frequency on the loss and junction temperature of IGBT power module, the loss of IGBT power module of three-phase grid-connected inverter is analyzed in this paper. Aiming at the problem that the traditional power device loss model of three-phase inverter is limited to SPWM modulation strategy, and the influence of device junction temperature on loss is insufficient, this paper deduces the formula for calculating power device loss of three-phase grid-connected inverter under SVPWM modulation. According to the user parameters of power devices, the loss of IGBT power devices is calculated by curve fitting, and the influence of switching frequency on the loss of IGBT power modules is analyzed. It provides a theoretical basis for changing switching frequency to adjust junction temperature. Secondly, because switching frequency is an important factor that affects the loss of IGBT power module, in order to realize the effective control of the junction temperature of IGBT power module, this paper presents a real-time switching frequency control method for IGBT power module junction temperature. Through the establishment of wind power converter junction temperature prediction model to extract the variable switching frequency junction temperature control parameters, obtained the current, switching frequency, IGBT power module junction temperature fluctuation value of the functional expression. The feasibility of using the function relation to control the junction temperature of IGBT power module is verified by simulation. Then, in order to realize the variable switching frequency control of three-phase grid-connected inverter in digital circuit, this paper presents a method of realizing variable switching frequency based on FPGA. The method is based on the top-down design idea of FPGA and the characteristics of parallel operation. The whole control module is divided into several sub-modules, each module running independently and in parallel. The logic behavior of SVPWM algorithm module, Cordic algorithm module and three-phase phase-locked loop sub-module are programmed by VHDL language. The algorithm logic of the module is verified by Modelsim software simulation, which verifies the feasibility of variable switching frequency of three-phase inverter under SVPWM modulation. Finally, a three-phase inverter variable switch junction temperature control experimental platform is built, with DSP as the sampling part and FPGA as the control core, the switching frequency changes are compared when the output current changes. The rationality and feasibility of the proposed method are verified.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN322.8;TM464

【參考文獻】

相關期刊論文 前8條

1 劉東海;韋忠善;;直流電機PID控制器的FPGA設計與實現(xiàn)[J];水電能源科學;2016年04期

2 張常江;宋法質;劉洋;宋躍;陳興林;;光刻機同步控制卡DSP與FPGA通信方案設計[J];自動化技術與應用;2016年01期

3 張偉文;高偉強;林淦;劉建群;閻秋生;;OMAP-L138DSP與FPGA通信方案設計[J];機電工程技術;2015年10期

4 周雒維;吳軍科;杜雄;楊珍貴;毛婭婕;;功率變流器的可靠性研究現(xiàn)狀及展望[J];電源學報;2013年01期

5 朱曉琴;秦生升;;基于SVPWM的直驅式風電系統(tǒng)網側變換器控制策略[J];鹽城工學院學報(自然科學版);2012年01期

6 鄭征;葛廣凱;;三相PWM整流器交流側電感的設計[J];電氣傳動;2011年03期

7 鄭忠玖;李國鋒;王寧會;;基于dq變換的三相VSR的研究[J];電源學報;2011年02期

8 陳明;胡安;唐勇;汪波;;絕緣柵雙極型晶體管傳熱模型建模分析[J];高電壓技術;2011年02期

相關碩士學位論文 前4條

1 于燕來;基于驅動電路參數(shù)調整的功率模塊結溫控制研究[D];重慶大學;2015年

2 朱小燕;三相高功率因數(shù)PWM整流器的研究與設計[D];湖南大學;2013年

3 王萬寶;三相電壓型SVPWM整流器仿真研究[D];重慶大學;2009年

4 周柱;基于CORDIC算法的直接頻率合成技術的研究和應用[D];國防科學技術大學;2005年

，

本文編號：2390548