Grid-connected control method for photovoltaic power generation system

A technology of photovoltaic power generation system and control method, which is applied in the direction of photovoltaic power generation, AC network voltage adjustment, single-network parallel feeding arrangement, etc., can solve problems affecting system stability, increase equipment investment, etc., and reduce hardware investment and equipment volume , improve cost performance, and reduce the effect of voltage waveform distortion

Inactive Publication Date: 2016-03-30
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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Problems solved by technology

But these measures will not only increase additional equipment investment, but also affect the stability of the system

Method used

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  • Grid-connected control method for photovoltaic power generation system
  • Grid-connected control method for photovoltaic power generation system
  • Grid-connected control method for photovoltaic power generation system

Examples

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Embodiment Construction

[0020] figure 1 Shown is a diagram of a three-phase photovoltaic power generation system with power quality regulation function, including photovoltaic arrays, DC / DC converters, three sets of single-phase full-bridge inverters, LCL filters, distributed power grids, and TMS320F2812 control device.

[0021] The DC / DC converter mainly completes the maximum power tracking of the photovoltaic cell array, and uses high-frequency link technology to convert the low-voltage fluctuating DC power into the stable high-voltage DC power required by the grid-connected inverter. The converter utilizes a phase-shifted full-bridge soft-switching circuit topology to improve system efficiency and power density. The system inner loop (current control loop) tracks the maximum power point of the photovoltaic cell array by changing the duty cycle, and the voltage outer loop ensures that the DC side voltage of the subsequent active inverter is constant.

[0022] The DC / AC inverter adopts three group...

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Abstract

The invention relates to a grid-connected control method for a photovoltaic power generation system. An active power is injected into a grid-connected point; and a harmonic wave, a reactive power of a load and an unbalanced three-phase current of the grid-connected point are compensated. The grid-connected control method has the beneficial effects that (1) an essential grid-connected inverter in photovoltaic power generation is adopted, so that the inverter simultaneously achieves injection of the active power into a distributed power grid and compensation on the harmonic wave, the reactive power of the load and the unbalanced three-phase current of the grid-connected point; hardware resources of the inverter are utilized to the maximal extent; hardware investment and equipment volume are reduced; and the cost performance is improved; (2) a phase-locked loop-free technology is adopted; an extra hardware phase-locked element or a complicated software phase locking procedure is reduced; and influences caused by voltage waveform distortion, network voltage change, frequency offset and the like are reduced; and (3) a weighted current feedback-based hysteresis current control strategy is adopted; a control system is reduced to the first order from the fifth order; and design of the control system is simplified.

Description

technical field [0001] The invention relates to a photovoltaic grid-connected power generation technology, in particular to a grid-connected control method for a photovoltaic power generation system. Background technique [0002] Photovoltaic grid-connected power generation technology has increasingly become an effective way to solve the double crisis of human energy shortage and environmental pollution due to its advantages of inexhaustibility and environmental protection. However, photovoltaic power generation has the characteristics of randomness and intermittency, and is a typical uncontrollable source. And the distributed power grid is an important way for distributed power to connect to the power grid, but it has a large number of power electronic equipment, which generates a large number of harmonics. And there are nonlinear, unbalanced and reactive characteristics in the local load of the distributed grid, which will deteriorate the power quality at the point of com...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/01H02J3/16H02J3/26
CPCY02E10/56Y02E40/30Y02E40/40Y02E40/50
Inventor 江友华陈江伟黄锦王林王润超田书锦刘耀辉张嘉堃
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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