外文翻譯---電動汽車dc-dc電源轉(zhuǎn)換器的原理、建模和控制-汽車設(shè)計-預(yù)覽頁
【正文】 4 = 01104. ( 4 ) Design of the PID Regulator 2. The Principle Scheme and Transfer Function of the PID Regulator To resist the disturbance of the power supply voltage and load current to the DCDC convertor so as to improve control precision , an integral pensator is adopted. The principle scheme of the integral pensator is shown in Fig. 7. Fig. 7 The principle scheme of the integral pensator It s transfer function is Gc ( s) = Ki/ s = 1/ ( RCs). ( 5 ) In Fig. 7 and Eq. (5), R = 10 kΩ , C = F , Ki = 1/ ( RC) = 1/ (10 103 011 10 6)= 1 000. 2. The Bode Drawing of the System OpenLoop Transfer Function The system openloop transfer function is the product of the controlled object’ s , feedback and measuring circuit’ s and integral pensator’ s transfer functions. We have G( s) = Gc ( s) Gp ( s) Gb ( s) = The system Bode drawing is shown in Fig. 8 from Eq. (6). The curves ① and ④ are respectively the logarithmic gainfrequency characteristic ,logarithmic phasefrequency characteristic of controlled object Gp ( s). The curves ② and ⑤ are respectively the logarithmic gainfrequency characteristic , logarithmic phasefrequency characteristic of the feedback and measuring circuit joint the integral pensator. The curves ③ and ⑥ are respectively the logarithmic gainfrequency characteristic and logarithmic phasefrequency characteristic of the pensated openloop system. By Fig. 8 we know that the system is Imodel system. When the input doesn’ t change , there isn’ t steadystate error. It s original phasemargin frequency ω c = 1 016 rad/ s , phase margin γ = 176。 數(shù)學模型 。它的額定電壓 24 V或 12 V低壓供電 ,可由高電壓供電直流 直流變換器得到 在本文中 ,主要性能設(shè)計的是輸入電壓轉(zhuǎn)換器 ,范圍從直流 250 V 到直流 450 V,輸出直流電壓 24 V、最大輸出電流是直流 20 A,輸出精度為 1%。這個轉(zhuǎn)換器是一個 負 電壓反饋閉環(huán)系統(tǒng) 。 圖 2 電路的電源開關(guān)半橋接模式 1 圖 3 用于 PWM 控制電路的 SG3525 芯片 1 2 1 1 PID 調(diào)節(jié)器的原理方案及傳遞函數(shù) 直流 — 直流轉(zhuǎn)換器的抗擾動電源電壓和負載電流，以提高控制精度采用整體補償、積分補償器的原理如圖 7 圖 7 整體補償原則 它的傳遞函數(shù) Gc(s)=Ki/s=1/(RCs) ( 5 ) 由圖 7和公式 5 , R = 10 kΩ , C = F , Ki = 1/ ( RC) = 1/ (10 )= 1 000 2由圖 8 我們知道系統(tǒng)是自我模型系統(tǒng)，當輸入不改變，沒有穩(wěn)態(tài)誤差。 表一 當負載電阻 RL = 表二 當負載電阻 RL = 4總結(jié) ①由于采用的整體補償法，即使輸入電壓和負載變化，轉(zhuǎn)換器的輸出電壓 Uo 有 很高的精度； ②脈沖的寬度自動調(diào)整來實現(xiàn)變頻器輸出電壓不變，隨輸入電壓的增加脈沖的寬度將縮小，轉(zhuǎn)換器的效率下降，在設(shè)計 DCDC轉(zhuǎn)換器的過程中，當轉(zhuǎn)換器運作時我們必須減少脈沖寬度的可調(diào)范圍和是脈沖寬度更寬； ③反饋電路中電阻和電容器合理的價值必須選擇為能夠使反饋系統(tǒng)有足夠的增益和極限來保證控制系統(tǒng)可以順利進行調(diào)整 5參考文獻 [ 1 ] Cai Xuansan , Gong Shaowen. High2frequency electronics ( in Chinese) [ M] . Beijing : Science Press , 1994. 232 246. [ 2 ] Zhang Wang , Wang Shiliu. Automatic control principle (in Chinese) [M] . Beijing : Beijing Insti2 tute of Technology Publishing House , 1994. 71 72. [ 3 ] D’ Azzo J J . Linear control system analysis and design [M] . San Francisco : McGraw2Hill Book Company ,1981. 83 92.
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