Control system for three-phase cascaded multilevel photovoltaic grid-connected inverter

Abstract

The invention discloses a control system for a three-phase cascaded multilevel photovoltaic grid-connected inverter. The control system comprises a master controller, an optical fiber communication unit, multiple sub controllers, first drivers, second drivers, a zero-crossing comparator and a voltage transformer. The master controller is connected with all the sub controllers through the optical fiber communication unit. The sub controllers are used for driving signals of DC-DC modules to be directly connected with the second drivers, the sub controllers are used for driving signals of DC-AC modules to be multiplied by output signals of the zero-crossing comparator and then to be connected with the first drivers. The control system for the three-phase cascaded multilevel photovoltaic grid-connected inverter is simple in structure and convenient to operate, independent control over all the DC-DC modules and all the DC-AC modules of the three-phase cascaded multilevel photovoltaic grid-connected inverter can be achieved, work of different modules in the same phase does not affect each other, the three-phase inverter is totally independently controlled, the reliability and the stability of a circuit are improved, the DC voltage utilization rate of the controlled three-phase cascaded multilevel photovoltaic grid-connected inverter is high, the switching frequency of a switching pipe is low, and the system energy utilization rate is high.

Description

Technical field [0001] The invention relates to the field of photovoltaic inverter power generation equipment, in particular to a three-phase cascaded multi-level photovoltaic grid-connected inverter control system specially used in photovoltaic power stations. Background technique [0002] With the development of human society, energy consumption is increasing, and the world's fossil energy will reach its limit one day. At the same time, due to the massive burning of fossil energy, the global ecological environment is deteriorating day by day, posing a great threat to human survival and development. In this context, solar energy, as a huge amount of renewable energy, has attracted people's attention, and governments of various countries are gradually promoting the development of solar photovoltaic power generation industry. [0003] As a topological structure of high-voltage and high-power converters, cascaded multi-level inverters have received close attention from expert...

AI Technical Summary

Problems solved by technology

However, the realization of cascaded multilevel inverters depends to a greater extent on the design of the control system and the choice of control methods. The more cascaded units, the more complex the control system.

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