THE VARIABLE DC LINK VOLTAGE CONTROL METHOD RELATED TO GRID VOLTAGE.

摘要

The system is a technology for maximizing conversion efficiency of a grid connected photovoltaic inverter. A conventional common grid connected photovoltaic inverter shown in Figure 1 is a system to boost the voltage generated in a photovoltaic panel and send to the system by converting boosted DC linked voltage into AC voltage. DC362V, which is the result value of a DC link voltage of maximum AC voltage AC242 is set to fixed DC link voltage by controlling a boost converter part and an inverter part by a system control part of the grid connected photovoltaic inverter regardless of the voltage generated from the photovoltaic plate and the system voltage and DC link voltage have to maintain at least DC362V at any time. In this case, conversion efficiency is deteriorated due to an unnecessary operation of the boost converter part. To solve the above problem, a variable DC link voltage control system in accordance with grid voltage is designed. The invention shown in Figure 2 is configured to allow the system control part of a grid connected photovoltaic inverter to calculate the optical DC link voltage corresponding to the detected voltage in real time based on the voltage detected from a grid voltage detecting part to set in a DC link reference part and boost to the optimal DC link voltage by controlling the boost converter part and the inverter part, thereby improving conversion efficiency.