A voltage measurement system of photovoltaic power supply for vehicle intelligent monitoring

Abstract

The invention discloses a voltage measurement system of a photovoltaic power supply for vehicle intelligent monitoring, which includes a power grid voltage acquisition circuit set based on a photovoltaic grid-connected inverter control system, which is established by using an off-line measurement standard sinusoidal input signal method, and between two adjacent points 8 reference points for the standard grid voltage RMS value of the inter-connection line, the grid voltage RMS measurement module for online measurement, and the result judgment and conditioning module for judging the measurement results and online correction; the grid voltage acquisition circuit, the grid voltage RMS The measurement module is connected to the result judgment and conditioning module in sequence, and the eight standard grid voltage RMS reference points are respectively connected to the result judgment and conditioning module. The voltage measurement system of photovoltaic power supply for vehicle intelligent monitoring can overcome the defects of high hardware cost, large error and low detection accuracy of grid voltage effective value in the prior art, so as to realize low hardware cost, small error and accurate detection of grid voltage effective value The advantages of high degree.

Description

technical field [0001] The invention relates to the technical field of intelligent transportation, in particular to a voltage measurement system of a photovoltaic power supply for vehicle intelligent monitoring. Background technique [0002] In recent years, photovoltaic grid-connected technology has developed rapidly, and the standards of various countries have strictly stipulated that photovoltaic grid-connected inverters need to perform accurate over-voltage and under-voltage protection functions and low-voltage ride-through functions, which involves how to perform accurate RMS measurement of grid voltage. [0003] Some photovoltaic inverter manufacturers use a dedicated grid voltage true effective value chip to obtain the effective value of the grid voltage. For the distorted grid voltage, the accuracy of the effective value of the grid voltage obtained by this method is low, which is easy to cause system malfunction, and the hardware cost relatively high. [0004] In ...

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Problems solved by technology

[0003] Some photovoltaic inverter manufacturers use a dedicated grid voltage true effective value chip to obtain the effective value of the grid voltage. For the distorted grid voltage, the accuracy of the effective value of the grid voltage obtained by this method is low, which is easy to cause system malfunction, and the hardware cost relatively high

[0004] In order not to increase hardware costs, most photovoltaic inverter manufacturers use voltage sensors and ordinary operational amplifiers, resistors and capacitors to form signal conditioning circuits, and sample voltage instantaneous values ​​through single-chip or DSP analog-to-digital conversion (A / D). The algorithm calculates the effective value of the voltage to perform voltage protection. This method does not undergo special algorithm processing, and the sampled voltage A / D will deviate from the true value due to the zero drift, temperature drift, and resistance and capacitance errors of the operational amplifier in the conditioning circuit. At the same time, there is also noise signal interference, which leads to inaccurate calculation of the effective value of the grid voltage, thereby affecting the protection voltage action point, which cannot meet the requirements stipulated by the national standard

[0005] Therefore, it is necessary to try to solve the problem of inaccurate detection of the effective value of the grid voltage from the calculation method

[0006] To sum up, in the process of realizing the present invention, the inventor found that there are at least defects in the prior art such as high hardware cost, large error and low detection accuracy of grid voltage RMS

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