Paralleled current sharing control method of photovoltaic inverter

The invention discloses a paralleled current sharing control method of a photovoltaic inverter. By the method, a current momentary value is controlled in a rotation transformation manner. Compared with the traditional method by which current sharing is carried out on the basis of effective values, the paralleled current sharing control method is high in dynamic response speed. A closed-loop current sharing adjusting mode is used, the dynamic performance and the steady-state performance are high; after current sharing is performed on the photovoltaic inverter, ring current of a system is reduced obviously, and the system can run stably and reliably; extra hardware is not required, fault points are reduced, and the cost and the size of the system are prevented from being increased; and an adjusting mode is flexible, and load distribution of various power units can be adjusted flexibly as needed.

Short circuit detecting method and device for photovoltaic inverter

The invention relates to a short circuit detecting method and device for a photovoltaic inverter. The method includes a first step of detecting voltage to ground of the DC side of the photovoltaic inverter; a second step of acquiring power frequency common mode voltage of the DC side based on the voltage to ground of the DC side; and a third step of judging whether the AC side of the photovoltaic inverter meets short circuit or not according to the power frequency common mode voltage and a phase voltage of a grid side of the photovoltaic inverter. By applying the method and device provided by the invention, whether the AC side meets short circuit or not can be judged only with the voltage to ground of the DC side of the photovoltaic inverter. Therefore, method and device are simple in circuit detection and low in cost.

话音业务实时记录与分析系统及其方法

Traffic service signaling data in signaling chain of stored-program control exchange in each telecom dept. are corrected through signaling correction unit in real time. Signaling correction unit through network port transfers corrected data to signaling corrector. The signaling corrector stores traffic service signaling data onto storage. Signaling decoder in call ticket generation module decodes signaling data in the signaling corrector; and based on signaling data flow, call data record (CDR) is generated. According to time period, CDR is converted to file CDR so as to generate original call ticket data. File transferring server in the call ticket generation module saves signaling data (original call ticket data) decoded by signaling decoder in a designated directory for computer to down load. Further, voice service analysis module and assistant balance module can be added to the system in order to carry out voice service analysis and settling accounts.

Wave method of controlled silicon thyristor rectifier and its device