cycle n. 1.循環(huán),周期,一轉(zhuǎn)。 2.周時(shí),周年,年紀(jì)。 3.(詩(shī)、故事等的)始末。 4.自行車(chē),三輪車(chē),摩托車(chē)。 5.【電學(xué)】周波;【數(shù)學(xué)】環(huán);【拓】閉鏈;【地質(zhì)學(xué);地理學(xué)】旋徊;【植物;植物學(xué)】(從枯凋到再生的)一輪迥;天體運(yùn)轉(zhuǎn)的軌道。 the business cycle 商業(yè)盛衰的周期性。 the life cycle 【生物學(xué)】生命周期,生活史。 the Arthurian cycle 《亞瑟王記》。 the Calippic cycle 七十六年周期。 the Trojan cycle 《特洛伊戰(zhàn)爭(zhēng)史詩(shī)集》。 vi. 1.輪轉(zhuǎn),循環(huán)。 2.騎自行車(chē)[三輪車(chē)等]。 vt. 使循環(huán),使輪轉(zhuǎn)。 -ry (出售或修理自行車(chē)的)自行車(chē)鋪。
For ballasts with rest mode facility changeover from rest mode to normal mode shall occur automatically at greater than 0 . 9 times the off cycle extended to 3 s and the ballast put into the rest mode after 2 s of the off periods in the 500 switching cycles 帶有休止?fàn)顟B(tài)裝置的自容式應(yīng)急燈具,從休止向正常狀態(tài)的轉(zhuǎn)換應(yīng)在不大于0 . 9倍額定電壓下自動(dòng)運(yùn)行3秒,在500次開(kāi)關(guān)周期結(jié)束切斷電源的2秒時(shí)間內(nèi)應(yīng)使自容式燈具進(jìn)入休止?fàn)顟B(tài)。
High - frequency link power converters are receiving increasing attention . when the input frequency of ac - ac converter is quite high , such as 20khz or above , in order to make sure the converter switching action is restricted to the zero crossing point of the link voltage , the switching cycle becomes discrete pulse spectrums , however , the conventional pwm converters are ruled out because they would fail either to the efficiency or the low - distortion criteria 當(dāng)交-交變頻器的輸入頻率非常高,通常為20khz時(shí),為了在零電壓條件下實(shí)現(xiàn)逆變器開(kāi)關(guān)管的通斷,變換器的開(kāi)關(guān)時(shí)刻必須選擇在高頻交流電壓脈沖為零時(shí),這意味著變換器開(kāi)關(guān)時(shí)刻在時(shí)間軸上成為不連續(xù)的點(diǎn),而常規(guī)的硬開(kāi)關(guān)pwm變換器是將開(kāi)關(guān)時(shí)刻選擇在任意時(shí)刻。
The distortion introduced by switching power amplifier is typically larger than in their linear counterparts due to intrinsic nonlineariry of switching converter . one of the key factors of affecting fidelity of switching power amplifier is control technique . one cycle control theory developed since 1990s is a large signal nonlinear pwm technology , which basic concept is to force the average of the controlled switch - variable to be equal or proportional to the control reference in each switching cycle . one cycle control technique features the merit of simple circuit structure , high control precision , fast dynamic response , and control performance not affected by the variable of power parameters . it is very suitable to control switching power amplifier 控制技術(shù)是影響開(kāi)關(guān)功率放大器保真度的關(guān)鍵因素之一。單周控制理論是20世紀(jì)90年代初提出的一種大信號(hào)、非線性pwm控制技術(shù),其基本控制思想是保證在每一個(gè)開(kāi)關(guān)周期中開(kāi)關(guān)變量與控制參考量相等或成比例。它具有結(jié)構(gòu)簡(jiǎn)單、控制精度高、響應(yīng)速度快,控制性能不受電源參數(shù)變化影響等優(yōu)點(diǎn),因此非常適合于控制開(kāi)關(guān)功率放大器。