Solar photovoltaic water heater and control method

Abstract

The invention relates to the field of solar photovoltaics, and provides a solar photovoltaic water heater and a control method. The water heater comprises a heat storage water tank, a controller, a photovoltaic panel assembly, an electric heating assembly, a voltage detection piece and a current detection piece, wherein the photovoltaic panel assembly and the electric heating assembly are electrically connected with the controller, and thevoltage detection piece and the current detection piece are electrically connected with thephotovoltaic panel assembly; the resistance value of the electric heating assembly is adjustable, and the controller is used for adjusting the resistance value of the electric heating assembly according to the output voltage detected by the voltage detection piece and the output current detected by the current detection piece. The control method comprises the steps: adjusting the resistance value of the electric heating assembly; obtaining the output voltage and the output current of the photovoltaic panel assembly; calculating the output power of the photovoltaic panel assembly; traversing all the resistance values of the electric heating assembly in the adjusting process, and controlling the electric heating assembly to work according to the resistance value corresponding to the maximum output power; and if a preset condition is met, controlling the electric heating assembly to stop heating and repeating the steps. The maximum power point tracking of the photovoltaic panel assembly is realized, and the efficiency of the water heater is improved.

Description

technical field [0001] The invention relates to the field of solar photovoltaic technology, in particular to a solar photovoltaic water heater and a control method. Background technique [0002] With the improvement of solar photovoltaic power generation efficiency, solar photovoltaic water heaters have emerged as the times require. Solar photovoltaic water heaters are water heaters that convert solar energy into electrical energy and then use electrical energy to heat water. Compared with traditional solar photothermal systems, solar photovoltaic water heaters have at least the following advantages: First, because solar photovoltaic water heaters use electric energy to heat water, and do not rely on media, namely water and antifreeze, to transfer heat, thus avoiding leakage, leakage, etc. phenomenon occurs. Second, electric heating is used instead of medium for heat transfer, which not only saves space but also greatly reduces energy loss. Third, the photovoltaic power u...

AI Technical Summary

Problems solved by technology

The output power of photovoltaic panels is a dynamic variation affected by the weather, ambient temperature and heater resistance, but the existing solar photovoltaic water heaters do not take the above factors into account, resulting in the inability of solar photovoltaic water heaters to perform maximum power point tracking (Maximum Power Point Tracking). PointTracking, referred to as MPPT) operation, thereby affecting its efficiency

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