Maximal power matched transmission converting method and maximal power matched transmission converting device of photovoltaic cell

Abstract

The invention belongs to the field of photovoltaic cells and discloses a maximal power matched transmission converting method and a maximal power matched transmission converting device of a photovoltaic cell. The method comprises the following steps: (1) converting a characteristic of a current source output by the photovoltaic cell into a characteristic of a voltage source; (2) detecting the output voltage of the voltage source and controlling an integrated circuit to sample an output voltage value by pulse-width modulation (PWM); (3) adjusting the output duty ratio in such a way that a duty ratio signal is directly proportional to the output voltage value; (4) outputting the duty ratio signal and connecting a power switch pipe, wherein the power switch pipe is connected with the primary side of a high frequency transformer, and the secondary side is connected with a load by an output rectifying circuit; (5) adjusting the opening and the closing of the power switch pipe by the duty ratio signal, changing the input resistance characteristic of the primary side of the high frequency transformer, tracing and matching the equivalent internal resistance characteristic of the photovoltaic cell and realizing the maximal output power of the photovoltaic cell. The invention can realize rapid, continuous and smooth real-time maximal power matching and tracing and greatly reduce the development cost and the development requirement due to adopting no SCM or DSP chip.

Description

technical field [0001] The invention relates to the technical field of photovoltaic cells, in particular to a photovoltaic cell maximum power matching transmission conversion method and device. Background technique [0002] At present, the maximum power tracking of photovoltaic cells mostly adopts the following methods: [0003] 1. Power fixed distribution circuit: Select photovoltaic cells to make their output characteristics match specific loads in advance. Due to the uncertainty of the intensity of sunlight and load conditions, this technology can only roughly estimate the position of the MPP, and cannot Tracking and matching are realized according to the intensity of sunlight and changes in load conditions, and the utilization rate of photovoltaic cells is low. [0004] 2. Curve fitting technology: The output characteristics of photovoltaic cells are measured in advance and described by mathematical expressions. This method cannot predict the influence of some complex ...

AI Technical Summary

Problems solved by technology

In order to determine the maximum power point, it is necessary to temporarily disconnect the load and sample and hold the open-circuit voltage as the reference voltage of the control loop; however, this method is not suitable for situations where the environmental conditions change rapidly, and the calculation of the output power of photovoltaic cells generally requires a single-chip microcomputer or AD Conversion circuit, poor adaptability to load changes

[0007] 5. Incremental conductance method: This method overcomes the shortcomings of the perturbation observation method by comparing the instantaneous conductance and incremental conductance of photovoltaic cells. It is the most accurate of the above methods. The input impedance of the switching power supply is adjusted to match the photovoltaic cell impedance. The best matching value is achieved; this method works well even under rapidly changing environmental conditions, and usually requires the use of a single-chip microcomputer or DSP to implement this method, which increases the system cost and is not suitable for small-scale systems

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