CN-121995216-A - Diesel generator test system control method based on moving average filter

CN121995216ACN 121995216 ACN121995216 ACN 121995216ACN-121995216-A

Abstract

The invention relates to the technical field of power electronics, in particular to a control method of a diesel generator test system based on a moving average filter, which comprises the steps of collecting an output voltage instantaneous value of a diesel generator in real time and obtaining a voltage sampling sequence; the method comprises the steps of inputting a voltage sampling sequence into a pre-built moving average filter, carrying out moving average processing on the input voltage sampling sequence through the moving average filter to obtain an output signal, generating a current command signal based on the output signal of the moving average filter, driving a diesel generator test system to simulate a load with a specific power factor through current closed loop control according to the current command signal, and carrying out load simulation test on the diesel generator. The moving average filter is directly used for generating a current instruction of the test system, the hysteresis angle of the current instruction is linearly adjusted by adjusting the number of the filter points through the linear phase frequency characteristic of the filter, and the accurate and convenient control of the simulated load power factor of the diesel generator test system is realized.

Inventors

CHI ENXIAN
JU HONGBING
WANG DETAO
Dong Baojin
LIU HUI
SUN XIBIN
ZHAO YONGHENG

Assignees

山东华天电气有限公司
山东华天科技集团股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260410

Claims (9)

1. A method for controlling a diesel generator test system based on a moving average filter, comprising: S1, acquiring an output voltage instantaneous value of a diesel generator in real time, and acquiring a voltage sampling sequence; S2, inputting the voltage sampling sequence into a pre-constructed moving average filter, and carrying out moving average processing on the input voltage sampling sequence through the moving average filter to obtain an output signal; S3, generating a current instruction signal based on an output signal of the moving average filter; And S4, driving a diesel generator testing system to simulate the load with a specific power factor through current closed-loop control according to the current command signal, and performing load simulation test on the diesel generator.
2. The control method of a diesel generator testing system according to claim 1, wherein in S2, the input voltage sampling sequence is subjected to a moving average process by a moving average filter, and the processing procedure is as follows: maintaining a first-in first-out data queue with the length of N, inserting new voltage sampling data into the tail of the queue and removing the oldest data at the head of the queue every time new voltage sampling data are acquired, and calculating the arithmetic average value of all N data in the current queue to be used as the output value at the current moment.
3. The diesel generator test system control method of claim 2, wherein the output value is an ac signal at the same frequency as the diesel generator output voltage with a target phase angle lag.
4. The diesel generator test system control method of claim 1, further comprising, after S1, performing a fast fourier transform on the voltage sampling sequence collected by S1 to determine an actual power of the current diesel generator output voltage.
5. The control method of a diesel generator testing system according to claim 4, wherein the performing a fast fourier transform on the voltage sampling sequence collected in S1 specifically includes: Continuously collecting the output voltage instantaneous value of the diesel generator at a fixed sampling frequency f s , obtaining a data point of a complete time period, and storing the data point into a cache array; Windowing, namely applying a window function to data points of the cache array to obtain a windowed discrete sequence x (n); Performing Fast Fourier Transform (FFT) on the windowed discrete sequence X (n) to obtain a spectrum sequence X (k), wherein k=0, 1, M-1, M is the FFT point number; The fundamental frequency identification is that in the preset fundamental frequency searching range, the spectral line index k max corresponding to the spectral component with the largest amplitude is determined; calculating the frequency, namely calculating the fundamental frequency f act of the current voltage signal according to the spectral line index and the actual frequency as follows: where f s is the sampling rate and M is the FFT point number.
6. The diesel generator test system control method of claim 4, wherein S2 further comprises performing a parameter adjustment and an amplitude compensation coefficient calculation of the moving average filter based on the determined actual power of the diesel generator output voltage.
7. The method for controlling a diesel generator testing system according to claim 6, wherein the performing parameter adjustment and amplitude compensation coefficient calculation of the moving average filter specifically includes: Presetting a target power factor required by a diesel generator test system, and calculating a required phase angle hysteresis degree phi target =arccos(P F according to the target power factor P F ; According to the determined actual frequency f act of the output voltage of the diesel generator and the required phase angle hysteresis degree phi target , the number N new of the required moving average filter is reversely calculated according to a phase frequency response formula and/or the sampling rate f s is adjusted; According to the determined actual frequency f act , sampling rate f s and the number of required moving average filter points N new , the amplitude gain H of the current moving average filter is calculated according to an amplitude-frequency response formula, and the reciprocal K=1/H is calculated as an amplitude compensation coefficient.
8. The diesel generator testing system control method of claim 7, wherein the phase-frequency response formula is: in the formula, The phase angle hysteresis is in degrees and the unit is degree; the unit is Hz; Is the actual signal frequency in Hz.
9. The diesel generator test system control method of claim 7, wherein the amplitude-frequency response formula is: where H is the amplitude-frequency response, N is the number of points of the moving average filter, The unit is Hz; Is the actual signal frequency in Hz.

Description

Diesel generator test system control method based on moving average filter Technical Field The invention relates to the technical field of power electronics, in particular to a control method of a diesel generator test system based on a moving average filter. Background The load test of the diesel generator is a key link for ensuring stable performance, safety and reliability of equipment. By verifying the electrical parameters, mechanical properties and safety protection functions of the generator under different load conditions, it is possible to verify its actual output capacity, discover potential faults, optimize maintenance strategies and extend the life of the equipment. The traditional testing method generally adopts a resistor load box to consume electric energy, which not only causes a great amount of energy waste, but also generates huge heat, thereby increasing the testing cost and the environmental burden. In order to solve the problem, an energy feedback type test system of a diesel generator set is proposed in the prior art. The system can simulate various load characteristics, accurately test the output power and the load capacity of the generator set, and feed the electric energy generated in the test back to the power grid with high efficiency, thereby realizing energy conservation and consumption reduction. However, unlike the commercial power grid, which is huge in capacity and stable in voltage, the diesel generator is limited in capacity and poor in stability of output voltage. When the load changes, the output voltage of the load is significantly affected, and even the frequency of the output voltage is suddenly changed. For a high-precision diesel generator set energy feedback type test system, the abrupt change of input voltage frequency can cause the decrease of the output stability of the test system, the increase of output current ripple, the unbalance of an internal control loop and the increase of power element stress, and finally the deviation of a test result is caused. In extreme cases, abrupt frequency changes may lead to a disorder in the control timing of the test system, so that electric energy is reversely supplied to the generator, and such reverse current impact may burn the internal windings or control modules of the generator, resulting in serious safety accidents. Therefore, how to realize a simple and reliable control method of a test system capable of effectively influencing the abrupt change of the output voltage frequency of the diesel generator is a technical problem to be solved by the person skilled in the art. Disclosure of Invention In order to solve the above problems, the present invention provides a control method for a diesel generator test system based on a moving average filter, comprising: S1, acquiring an output voltage instantaneous value of a diesel generator in real time, and acquiring a voltage sampling sequence; S2, inputting the voltage sampling sequence into a pre-constructed moving average filter, and carrying out moving average processing on the input voltage sampling sequence through the moving average filter to obtain an output signal; S3, generating a current instruction signal based on an output signal of the moving average filter; And S4, driving a diesel generator testing system to simulate the load with a specific power factor through current closed-loop control according to the current command signal, and performing load simulation test on the diesel generator. S2, performing moving average processing on the input voltage sampling sequence through a moving average filter, wherein the processing procedure is as follows: maintaining a first-in first-out data queue with the length of N, inserting new voltage sampling data into the tail of the queue and removing the oldest data at the head of the queue every time new voltage sampling data are acquired, and calculating the arithmetic average value of all N data in the current queue to be used as the output value at the current moment. The output value is an alternating current signal which has the same frequency as the output voltage of the diesel generator and has target phase angle hysteresis. After the step S1, the control method of the diesel generator test system further comprises the step of performing fast Fourier transform on the voltage sampling sequence acquired by the step S1, and determining the actual power of the current diesel generator output voltage. The operation of performing fast Fourier transform on the voltage sampling sequence acquired by the S1 is specifically as follows: Continuously collecting the output voltage instantaneous value of the diesel generator at a fixed sampling frequency f s, obtaining a data point of a complete time period, and storing the data point into a cache array; Windowing, namely applying a window function to data points of the cache array to obtain a windowed discrete sequence x (n); Performing Fast Fourier Transform (FFT) on the windowe