A cascaded inverter control system and control method

Abstract

The invention discloses a control system and control method of a cascaded inverter. The control system comprises a master controller and a broadcasting network, wherein the broadcasting network comprise slave controllers in one-to-one correspondence to each inversion unit, in each communication period, the master controller and each slave controller sequentially occupy a bus, the master controlleris used for acquiring data with change rate lower than a threshold in running data of an AC load and sending the data to the bus, and each slave controller is used for acquiring data with change ratelower than the threshold in running data of the corresponding inversion unit, sending the data to the bus, acquiring the data transmitted from the bus, calculating a modulation voltage, modulation degree and a duty ratio of the corresponding inversion unit according to the data acquired by the slave controller and the data transmitted from the bus and driving a power electronic switch in the corresponding inversion unit. By the control system, the requirements on the communication rate and the baud rate are reduced on the premise that the control performance and the bandwidth are enabled notto be changed, and the stability and the robustness of the system are improved.

Description

technical field [0001] The present invention relates to the technical field of communication, and more specifically, to a cascaded inverter control system and control method. Background technique [0002] figure 1 A cascaded inverter is shown, which includes a plurality of inverter units, the output side of each inverter unit is connected in series to an AC load, and the input side is connected to an independent DC source. [0003] For the control of cascaded inverters, an existing method is to use a master controller and slave controllers corresponding to each inverter unit to form a broadcast network. Among them, the main controller collects the AC load and the operation data of each inverter unit, calculates the data with a very high change rate such as the modulation voltage, modulation degree and duty cycle of each inverter unit, and then sends it to the communication bus in the form of broadcast Above, each slave controller obtains the data transmitted on the communi...

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Problems solved by technology

[0004] However, with the increase in the number of inverter units, the amount of data with a very high rate of change to be sent in the broadcast network is increasing. In the case of constant bandwidth, in order to ensure control performance, the required communication rate and The higher the baud rate, the higher the communication cost

Moreover, certain measures must be taken to avoid or deal with the occurrence of bit errors and packet loss during the transmission of the data with a very high rate of change, and the system stability and robustness are poor

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