Control method of restraining output DC component of grid-connected photovoltaic inverter

A technology of DC component and control method, which is applied in the direction of output power conversion device, conversion of AC power input to DC power output, photovoltaic power generation, etc. Advanced problems, to achieve the effect of convenient control, low cost and obvious effect

Active Publication Date: 2009-11-11
HARBIN INST OF TECH
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Problems solved by technology

[0009] The purpose of the present invention is to solve the problems of high cost of the DC blocking capacitor system with large capacity and large volume, large power consumption and high price of the industrial frequency transformer in suppressing the DC component of the output current of the photovoltaic grid-connected inverter, and provides a A Control Method for Suppressing Output DC Component of Photovoltaic Grid-connected Inverter

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  • Control method of restraining output DC component of grid-connected photovoltaic inverter
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  • Control method of restraining output DC component of grid-connected photovoltaic inverter

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specific Embodiment approach 1

[0021] Specific implementation mode one: the following combination Figure 3 to Figure 8 Describe this embodiment, the method of this embodiment is:

[0022] Sampling to obtain the output voltage V of the photovoltaic panel PV and current I PV , the voltage V PV and the current I PV Generate the command voltage V through the maximum power point tracking algorithm MPPT PV * , the command voltage V PV * Subtract the voltage V PV After that, the voltage difference is formed, and the voltage difference is adjusted by PI to generate the grid-connected command current amplitude I gref ; AC grid-connected voltage v obtained by sampling g The signal sinθ is generated through the adjustment of the phase-locked loop, and the signal sinθ is related to the grid-connected command current amplitude I gref multiplied to generate command current I ac * , the command current I ac * Subtract the DC component I caused by the sampling error grid * Form the corrected command curren...

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Abstract

The invention relates to a control method of restraining the output DC component of a grid-connected photovoltaic inverter, which pertains to the technical field of inverting grid-connected control. The invention is proposed for solving the problems of high cost of the adoption of a high-capacity blocking capacitor system and the large volume, high power consumption and high price of the adoption of a power frequency transformer during the restraining of the output DC component of a grid-connected photovoltaic inverter. The method of the invention adopts the grid-connected current, attains the DC component thereof and carries out restraining by two steps: 1. DC component due to sampling errors is introduced into the given grid-connected current in a manner of inverse feedback; 2. the average DC component of the modulating signals of each switch cycle in the previous power frequency period is obtained and then the DC component due to unbalanced impulse width is formed after PI regulation and introduced into the primary modulating signals in a manner of inverse feedback. With the two steps, modulating signals of restraining DC component are finally formed and PWM driving signals are obtained for driving the four switching tubes of the grid-connected photovoltaic inverter.

Description

technical field [0001] The invention relates to a control method for suppressing the output DC component of a photovoltaic grid-connected inverter, and belongs to the technical field of inverter grid-connected control. Background technique [0002] In today's society, energy has become one of the key issues restricting the development of the world economy. The fundamental way to solve the energy problem is to develop and utilize environmentally friendly new renewable energy, among which solar power generation is a good development direction. [0003] At present, my country's photovoltaic power generation system is mainly a DC system, that is, the electric energy generated by the solar cell is used to charge the battery, and the battery directly supplies power to the load. DC system. This type of system has a simple structure and low cost, but due to the different load DC voltages (such as 12V, 24V, 48V, etc.), it is difficult to achieve system standardization and compatibil...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02M7/5395
CPCY02E10/563Y02E10/56
Inventor 王卫徐殿国刘鸿鹏姜世公刘桂花吴辉
Owner HARBIN INST OF TECH
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