Application of unary linear regression frequency measurement algorithm in direct-current charging machine

Abstract

The invention relates to application of a unary linear regression frequency measurement algorithm in a direct-current charging machine. The application comprises the steps of detecting a signal zero crossing point position and carrying out unary linear regression analysis on a signal value near the zero passing point so as to obtain an intercept of the signal on a time axis coordinate to serve asa signal zero passing point time value. By applying the method, the phenomena of quite long filtering time and unstable measurement results caused by harmonic waves, noise and interference of an electric power system in the traditional zero passing point detection method are avoided; frequency calculation precision is improved; the method is not sensitive to accuracy of the zero passing point positions of the actual signal, and the algorithm detection processes are simplified; through the designed integrated direct-current charging machine, output power can be adjusted in real time according to frequency fluctuations of a power grid input source, so an effect of adjusting load of the power grid is achieved; and the application of the algorithm is very important in stabilization and balancing of power generation and the load.

Description

technical field [0001] The invention belongs to the field of DC chargers, and in particular relates to the application of a one-element linear regression frequency measurement algorithm in DC chargers. Background technique [0002] The current off-vehicle DC chargers in the market all have the characteristics of high charging power and high efficiency. The power of common integrated DC chargers ranges from 30kW to 210kW, and the number of chargers in DC fast charging stations is large and concentrated. If Simultaneous work of multiple chargers will increase the load of the grid, which will cause insufficient active power of the system, resulting in a decrease in the generator speed and a decrease in the frequency of the grid; on the contrary, if the load of the grid decreases, it will cause excess active power in the system, resulting in a generator As the speed increases, the grid frequency increases. At this time, if you want to restore the grid frequency to the rated fre...

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Problems solved by technology

However, in actual application, because the signal contains harmonics and is disturbed by environmental noise, etc., the measured actual signal fluctuates near the zero-crossing point, which makes the actual calculated frequency error too large, which limits the application of this method.

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