AN3095 datasheet(44/55 Pages) STMICROELECTRONICS

44 / 55 page

STM32F103xx-based current control strategy for inverter grid connection

AN3095

44/55

Doc ID 16555 Rev 3

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Open loop operation

This mode of operation was implemented to allow system debug independently from grid

operation. This mode, used for maintenance, test and debug, allows system operation only

with manual control by acting on a set of pushbuttons on the microcontroller board. The DC-

DC converter power transfer may be adjusted by acting on the phase-shift parameter

through the pushbutton placed on the microcontroller board. In the same way, the power

transfer of the DC-AC converter may be modified acting on the modulating index.

The dead time of the power bridges in each converter may also be adjusted.

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LCD display

The microcontroller board is equipped with a graphic LCD display. The selectable functions

are:

Open-loop mode

Closed-loop mode

Calibration

DC-DC converter manual control

DC-AC converter manual control

It is important to note that the calibration function must be performed by the operator when

the system is first connected to the grid. In this way, any offset affecting the feedback signals

used for control mode operation is compensated via firmware. When the calibration function

is executed the display shows a grid current offset of about 2.5 V and a grid-voltage offset of

about 1.8 V.

AN3095 Datasheet(PDF) 44 Page - STMicroelectronics