外文翻譯---單相spwm逆變器并聯(lián)解耦控制策略-展示頁(yè)
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【正文】 erter, is a proportional coefficient. In ,the power stage includes a fullbridge configuration and an LC filter, is DC link voltage, to are power switches, L and C are filter inductor and capacitor,is a sinusoidal reference voltage signal of the inverter,is the sum of inductor equivalent series resistance, switch onresistance, and connectionline resistance. According to nonlinear control and feedback linearization theory, openloop averaged output voltage can be characterized by (1)where means the average value of x over one switching cycle and u is the control variable, which can take the values 1,0,or1,depending on the state of switches , the dual closedloop feedback control inverter shown in ,the controller can be characterized by (2)From (1) and (2) ,the dynamic characteristics of the closedloop output voltage can be expressed in Laplace domain as (3)The single phase dual closedloop inverter can be modeled by two terminal equivalent circuits as (4) (5) (6) diagram of Single phase dual closedloop inverter.Frequency (rad/sec)(a)Frequency (rad/sec)(b) diagram of the voltage gain and the equivalent outputimpedance of the dual closedloop inverter:(a)magnitude vs.frequency and(b)phase . equivalent circuit.where is the voltage gain andis the equivalent output impedance. The bode diagram ofandare shown in . From (6), we can know that the equivalent output impedance is closely related to the parameters of the output filter and the feedback control parameters. Let R be the resistive ponent and X the inductive ponent of equivalent impedance Z(s).The inverter equivalent circuit can be shown as , , and,the relations between the impedance ratio and the control parameters, andare shown in . between the impedance ratio R/X and control parameters:(a)R/X vs.,(b)R/X vs.,and(c)R/X vs..From , the equivalent output impedance trends to be resistive when PI control parameterandare increasing, and trends to be inductive when PI control parameteris increasing. In the design of dual closedloop single phase inverter, the PI control parameters must be chosen carefully as they affect both the transient characteristics of the inverter and the current sharing performance of the inverter parallel system.3. Analysis of Inverter Parallel SystemBased on above discussion, the equivalent circuit of inverter parallel system of two inverter modular can be given as , whereis load voltage, andare the output voltage and equivalent output impedance of inverter 1,andare the output voltage and equivalent output impedance of inverter the inverter parallel system, the active output power and the reactive output power of the inverter 1 can be expressed as: (7)Due
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