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Three-ring control method and three-ring control device of single-stage type photovoltaic grid-connected inverter system

An inverter system and three-loop control technology, applied in output power conversion devices, photovoltaic power generation, single-grid parallel feeding arrangements, etc., can solve the problems of speeding up power tracking time, unstable bus voltage, and long tracking time, etc. Achieve the effect of improving the dynamic response performance, the grid-connected current is not distorted, and increasing the hardware cost

Active Publication Date: 2012-11-14
SOUTH CHINA UNIV OF TECH +1
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Problems solved by technology

The control method and its device aim at the disadvantages of long tracking time and poor dynamic response in the traditional control method using fixed-step disturbance observation, and the disadvantages of bus voltage instability in the traditional double-loop current control method , use the control method of variable step size disturbance observation to speed up the power tracking time and improve the dynamic response, and use the three-ring to realize the inverter grid connection function to stabilize the bus voltage and make the system work more reliable

Method used

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  • Three-ring control method and three-ring control device of single-stage type photovoltaic grid-connected inverter system
  • Three-ring control method and three-ring control device of single-stage type photovoltaic grid-connected inverter system
  • Three-ring control method and three-ring control device of single-stage type photovoltaic grid-connected inverter system

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Embodiment Construction

[0039] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings, but the implementation and protection of the present invention are not limited thereto.

[0040] Such as figure 1 The main circuit of the single-stage photovoltaic grid-connected inverter system shown is composed of: solar panels (shown by multiple parallelograms in the figure), bus capacitors, inverter bridges, filter inductors and the grid. The goal of the control device is to realize that the current output by the inverter is a sine wave with the same frequency and phase as the grid voltage. The control circuit includes a DSP controller, which adopts TI's DSP-TMS320LF2407A controller. Control peripheral device interfaces such as figure 1 As shown, it mainly includes sampling circuit, capture circuit and drive circuit. Mainly used in DSP controller ADC sampling module, EVA / EVB event management module, capture module, etc. Other module...

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Abstract

The invention discloses a three-ring control method and a three-ring control device of a single-stage type photovoltaic grid-connected inverter system. Three-ring control comprises a maximum power tracking outer ring, a direct-current voltage middle ring and a grid-connected current inner ring. Direct-current side voltage ring control is added so as to guarantee that the system can respond rapidly when outside illumination is reduced suddenly, direct-current bus voltage is stable in an operation process, and grid-connected current is not distorted. A maximum power tracking method adopts a step-variable disturbance observation method to enable the system to be operated at different voltage points so as to search the maximum power point rapidly. The control device comprises a sampling circuit, a capturing circuit, a digital signal processor (DSP) controller, a driving circuit and the like, and signals generated by the DSP controller are amplified by the driving circuit and sent to an inverter bridge to drive a switch tube. The control method can achieve that the single-stage type photovoltaic grid-connected inverter system can track the maximum power point rapidly when illumination varies frequently and is operated stably.

Description

technical field [0001] The invention relates to a control method for a photovoltaic grid-connected system, in particular to a three-loop control method for a single-stage photovoltaic grid-connected inverter system. Background technique [0002] Photovoltaic grid-connected power generation systems are divided into single-stage and multi-stage systems according to the topological level. The front-end photovoltaic panels of the single-stage grid-connected power generation system are directly connected to the grid through the inverter, which has the advantages of simple topology, low cost, and high efficiency, but its control strategy is complicated, and it needs to be connected to the grid on the control chip of the inverter Current control, taking into account maximum power tracking control and system stability. [0003] The main circuit of single-stage photovoltaic grid-connected system is composed of solar photovoltaic array, DC bus capacitor, inverter bridge, filter induc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02M7/5395
CPCY02E10/58Y02E10/563Y02E10/56
Inventor 杨苹陈红生
Owner SOUTH CHINA UNIV OF TECH
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