A parallel inverter carrier synchronization system and synchronization method

Abstract

A parallel inverter carrier synchronization system and synchronization method, including a plurality of parallel inverter units, each inverter unit is connected to a synchronization bus that transmits synchronization signals through an independent programmable logic device synchronization module, and the programmable logic device is synchronized The module is connected to the synchronization bus through a synchronization output port and a synchronization input port, and the synchronization module of the programmable logic device is connected to the MCU of the inverter unit through a synchronization output IO, which is connected to the external PWM synchronization input of the MCU port; all parallel inverter units send and receive synchronization signals to the synchronization bus, and the programmable logic device synchronization module adjusts its own synchronization cycle according to the synchronization signal on the bus, and finally makes its own synchronization output signal consistent with the bus synchronization signal; The status of each inverter unit in the invention is equal, and there is no need to distinguish the master from the slave. If any inverter unit in the system fails, the system will also have a synchronization signal, which greatly improves the reliability of the carrier synchronization signal.

Description

technical field [0001] The invention relates to the technical field of parallel inverter carrier synchronization, in particular to a parallel inverter carrier synchronization system and synchronization method. Background technique [0002] With the continuous expansion of the capacity of new energy power stations, the capacity of single inverters is getting larger and larger, and the parallel connection of inverters has become a trend of technological development. Parallel inverters are generally composed of multiple independent inverter units. During the working process, if the pulse width modulation steps between the inverter units are inconsistent, a circulating current will be generated between the inverter units, which will affect the parallel inverter. normal operation. In view of this situation, carrier synchronization technology is usually used to solve the circulation problem between parallel inverters. The traditional parallel inverter adopts a carrier synchroniza...

AI Technical Summary

Problems solved by technology

[0004] (1) In the system, only the host sends out the carrier synchronization signal. Once the host fails, it will cause the rest of the inverter units in the system to lose the synchronization signal, seriously affecting the reliable operation of the system;

[0005] (2) Even if there is host switching logic, that is, after the host fails, the system will automatically compete for a new host, but the host competition time is generally too long, and the synchronization signal will also be lost during the host competition, which will affect the reliable operation of the system;

[0006] (3) It is not conducive to the parallel operation of inverters: if two parallel inverters adopt the carrier synchronization method of one master and multiple slaves, when the two inverters need to be operated in parallel, due to the existence of two masters , the carrier synchronization bus of the two inverters cannot be directly connected, otherwise the carrier synchronization signal will be disordered;

[0007] (4) The synchronization process is easily affected by the interference pulse on the synchronization bus, causing false synchronization

Images