Maximum power point tracking control method and system thereof of photovoltaic electrical energy optimization

A maximum power point and electric energy optimization technology, applied in control/regulation systems, photovoltaic power generation, photovoltaic modules, etc., can solve the problem that the incremental conductance method cannot track the maximum power point in a timely and effective manner

Inactive Publication Date: 2012-04-04
董密 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, under the influence of noise, measurement error and digital control quantization error, this method cannot avoid the oscillation near the maximum power point, and the conductance incre

Method used

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  • Maximum power point tracking control method and system thereof of photovoltaic electrical energy optimization
  • Maximum power point tracking control method and system thereof of photovoltaic electrical energy optimization
  • Maximum power point tracking control method and system thereof of photovoltaic electrical energy optimization

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Example

[0065] First embodiment

[0066] image 3 with Figure 4 These are the schematic diagrams and schematic diagrams of the principles of the maximum power point tracking control method of this embodiment, and reference is made below figure 1 , image 3 with Figure 4 This embodiment will be described in detail.

[0067] The embodiment of the present invention is applied to the direct current / direct current (DC / DC) conversion stage of a photovoltaic power optimization system. Since the control of the photovoltaic power optimization system is switch control, specifically, by changing the duty cycle used to control the DC conversion stage switch Recently, the size of the reference voltage is controlled to track the maximum power point. The relationship between the output voltage and the input voltage and the duty cycle is different due to the structure of the DC conversion stage. E.g Figure 7 Schematic diagram of the structure, the relationship between voltage and duty cycle is U o / U ...

Example

[0124] Second embodiment

[0125] Figure 5 It is a schematic flow chart of the maximum power point tracking control method according to the second embodiment of the present invention. The embodiment will be described in detail below with reference to the drawings.

[0126] For ease of description, the same steps as those in the foregoing embodiment will not be expanded in detail, but only the differences from the foregoing embodiment will be described. in Figure 5 Here, the same reference numerals are used for steps that are the same as or similar to those in the foregoing embodiment.

[0127] It should be noted that when the external light intensity or the environment changes, the output power of the photovoltaic module and the change of the output voltage are generally proportional, that is, when the light intensity increases or decreases, dP PV / dV PV Is always greater than zero, according to formula (2), when the light intensity changes suddenly, dV PV / dI PV >0 always hol...

Example

[0140] The third embodiment

[0141] Image 6 It is a schematic flowchart of a maximum power point tracking control method according to the third embodiment of the present invention. This embodiment is a modification of the first embodiment and the second embodiment, and the first embodiment and the second embodiment are combined. Such as Image 6 As shown, the operation content of step 230 in the second embodiment is not executed after the operation content of step 540 in this embodiment (determining whether it is an environmental mutation) is completed, but the operation content of step 420 that is the same as the first embodiment is executed. , By determining whether the slope H is at the preset error threshold e to control the maximum power output.

[0142] This embodiment first judges the change of the external environment according to the second embodiment, and then performs the maximum power point tracking control according to the maximum power point tracking control method...

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Abstract

The invention discloses a maximum power point tracking control method and a system thereof of photovoltaic electrical energy optimization. The maximum power point tracking control method comprises the following steps of: step one, sampling output voltage and output current of a photovoltaic electrical energy optimized photovoltaic module to obtain the output voltage and the output current, and calculating and obtaining voltage variable quantity and current variable quantity in a default time period; step two, calculating slope of the output power to the output voltage curve based on the output voltage, the output current, the voltage variable quantity and the current variable quantity; step three, determining whether the slope is less than or equal to a default error threshold, if so, executing step four, otherwise, executing step five; step four, determining whether the mean value of the slope in the default time period equals to zero, if so, determining that the system works at the maximum power point, and returning step one; and step five, changing the value of the photovoltaic electrical energy optimized reference voltage by determining sign symbol of the slope and returning the step one.

Description

technical field [0001] The invention relates to a photovoltaic power generation system, in particular to a maximum power point tracking control method and system suitable for photovoltaic electric energy optimization. Background technique [0002] With the increasingly serious energy crisis and environmental pollution in today's world, solar energy has attracted more and more attention due to its advantages of no noise, no pollution, and energy available everywhere. However, due to the high cost of solar power generation, in recent years, researchers have focused on improving the stability and conversion efficiency of photovoltaic systems and reducing costs. [0003] Since the output voltage and output current of the photovoltaic module are strongly nonlinear with changes in sunlight intensity and ambient temperature, there is a unique maximum power output point (MPP for short) in a specific working environment. Among them, the maximum power point tracking (MPPT for short) ...

Claims

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Application Information

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IPC IPC(8): H02N6/00G05F1/67H02S40/30
CPCY02E10/58Y02E10/56
Inventor 董密杨建
Owner 董密
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