A sensorless grid-feed current control method suitable for grid-connected inverters

A current control and inverter technology, applied in the field of grid-connected inverter grid current control, can solve the problems of complex structure of the controller, poor grid-connected adaptability, difficult parameter design, etc., and achieve the goal of avoiding resonance and cascading failures Possibility, strong adaptability, and the effect of improving safe operation

Active Publication Date: 2019-06-21
SOUTHEAST UNIV
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Problems solved by technology

[0005] The purpose of the present invention is to provide a sensorless current control method suitable for grid-connected inverters to solve the existing controller structure of PI closed-loop control based on DQ rotating coordinates and PR closed-loop control under static coordinates Complicated, difficult parameter design, poor adaptability and poor grid connection adaptability and other problems

Method used

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  • A sensorless grid-feed current control method suitable for grid-connected inverters
  • A sensorless grid-feed current control method suitable for grid-connected inverters
  • A sensorless grid-feed current control method suitable for grid-connected inverters

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Embodiment

[0022] Example: such as figure 2 As shown, the schematic diagram of circuit connection for single-phase photovoltaic grid-connected inverter scenario with LCL filter is given, phase locking is performed through multiple grid voltages to provide phase information for the grid current reference signal, and the capacitance in the LCL filter is detected The instantaneous value of the voltage provides feed-forward compensation; the output voltage of the detected bridge arm and the input DC voltage are sent to the switch tube voltage drop compensation unit; the reference signal of the input current is passed through the first proportional regulator and the second proportional regulator of the open-loop control module of the input current. The regulator, the delayer, together with the feedforward compensation amount and the switching tube voltage drop compensation amount form a modulated wave and send it to the PWM generation module.

[0023] Specifically, the ratio of the first pro...

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Abstract

The invention relates to a current sensorless grid-connected current control method suitable for a grid-connected inverter, and relates to a system composed of a main circuit of a grid-connected inverter and a control circuit of a grid-connected inverter. The circuit includes a grid current open-loop control module and a PWM generation module, the grid current open-loop control module includes a first proportional regulator, a second proportional regulator, a delayer and an adder, the first proportional regulator and the second proportional regulator The input terminals of the regulators are all taken out as the input terminals of the input current reference signal, the output terminal of the first proportional regulator is connected to the input terminal of the adder, the output terminal of the second proportional regulator is connected to the input terminal of the delayer, and the delayer The output end of the adder is connected to the input end of the adder, and the output end of the adder is connected to the PWM generating module. The open-loop current control method adopted by this system can realize the grid-incoming AC current without static difference to track the grid-incoming current reference signal, and can adapt to harsh operating scenarios such as grid harmonics, unbalance, and faults.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverter current control technology, in particular to a current control strategy for grid-connected inverters suitable for accessing various voltage levels of grids, specifically a grid-connected inverter current control strategy suitable for grid-connected inverters. The current sensorless type grid current control method of the device. Background technique [0002] At present, the rapid development of new energy sources, such as photovoltaic power stations and wind farms, requires a large number of grid-connected inverters to send electric energy into the traditional grid; at the same time, offshore wind power is particularly suitable for sending power into the AC grid system through high-voltage direct current transmission. Therefore, a large number of power electronic converters connecting the DC system and the AC grid operate in different voltage levels of the power system. [0003] W...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCH02J3/38H02J3/381H02J2300/24Y02E10/56H02M7/53871Y04S40/121Y02E60/00H02J13/00009H02M7/49H02M7/4803
Inventor 肖华锋
Owner SOUTHEAST UNIV
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