cycle n. 1.循环,周期,一转。 2.周时,周年,年纪。 3.(诗、故事等的)始末。 4.自行车,三轮车,摩托车。 5.【电学】周波;【数学】环;【拓】闭链;【地质学;地理学】旋徊;【植物;植物学】(从枯凋到再生的)一轮迥;天体运转的轨道。 the business cycle 商业盛衰的周期性。 the life cycle 【生物学】生命周期,生活史。 the Arthurian cycle 《亚瑟王记》。 the Calippic cycle 七十六年周期。 the Trojan cycle 《特洛伊战争史诗集》。 vi. 1.轮转,循环。 2.骑自行车[三轮车等]。 vt. 使循环,使轮转。 -ry (出售或修理自行车的)自行车铺。
switch n. 1.(树上折下的)细树枝;软鞭子;鞭打。 2.假发;(尾巴上的)毛簇。 3.〔美国〕【铁道】道岔扳子,轨闸转辙器;侧线。 4.【电学】开关;电闸;电键;转换器;【电话】接线台。 5.【军事】斜行壕。 6.(思想等的)大转变。 7.〔美国〕(金融机构和销售店的)电脑化联网。 a change-over switch 转换开关,转向开关。 a pull switch 拉线开关。 a three wire switch 双联开关。 a time switch 定时断路器。 a clock switch 定时开关。 a line switch (自动电话的)寻线机,预选器;线路开关。 vt. 1.鞭打;摆动;摇(尾);猛然抢去。 2.挂断(…的电话)(switch sb. off);关闭(电流),关(电灯) (off; out)。 3.通(电流),接通(电话给某人),开(电灯) (on)。 4.改变,转变(思想、谈话等);【铁道】给扳道岔;调配(车厢)。 vi. 1.鞭打。 2.【铁道】扳道岔;调车。 3.挂断电话 (off)。 4.转换,转变。 switch an electric light on [off] 开[关]灯。 switch off to another like of thought 改变想法[思路]。 Let's switch. 〔美国〕走吧;开动吧。 I'll be switched. 〔美口〕〔表示否定、惊讶〕(I'll be switched if you do. 你要是能的话我就把头砍掉)。 switch off [on] 不收听[收听](某一广播)。 switch through 【电信】转接。
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 带有休止状态装置的自容式应急灯具,从休止向正常状态的转换应在不大于0.9倍额定电压下自动运行3秒,在500次开关周期结束切断电源的2秒时间内应使自容式灯具进入休止状态。
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 当交-交变频器的输入频率非常高,通常为20khz时,为了在零电压条件下实现逆变器开关管的通断,变换器的开关时刻必须选择在高频交流电压脉冲为零时,这意味着变换器开关时刻在时间轴上成为不连续的点,而常规的硬开关pwm变换器是将开关时刻选择在任意时刻。
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 控制技术是影响开关功率放大器保真度的关键因素之一。单周控制理论是20世纪90年代初提出的一种大信号、非线性pwm控制技术,其基本控制思想是保证在每一个开关周期中开关变量与控制参考量相等或成比例。它具有结构简单、控制精度高、响应速度快,控制性能不受电源参数变化影响等优点,因此非常适合于控制开关功率放大器。