CN115622059A - Frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression method - Google Patents

Frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression method Download PDF

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CN115622059A
CN115622059A CN202211222340.XA CN202211222340A CN115622059A CN 115622059 A CN115622059 A CN 115622059A CN 202211222340 A CN202211222340 A CN 202211222340A CN 115622059 A CN115622059 A CN 115622059A
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frequency
voltage
harmonic
inverter
droop
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于华龙
梅红明
任建功
刘树
董志然
操丰梅
朱辉
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Beijing Sifang Automation Co Ltd
Beijing Sifang Engineering Co Ltd
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Beijing Sifang Automation Co Ltd
Beijing Sifang Engineering Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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Abstract

A frequency self-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method is characterized in that a typical harmonic frequency droop control link is added in a droop control scheme of a traditional fundamental wave domain range, and a data sliding window mode is utilized to acquire and perform FFT analysis on voltage signals of grid-connected points to obtain typical harmonic frequency and amplitude of a load side, so that self-adaptive adjustment of the harmonic frequency droop link is realized, and harmonic waves of the load side are counteracted in a targeted manner.

Description

Frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method
Technical Field
The invention belongs to the technical field of multi-inverter parallel droop control, and particularly relates to a frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method.
Background
With the trend development of electric energy conversion towards high voltage, high power and the like, the original single inverter is difficult to meet the requirements, and meanwhile, the reliability and redundancy of the inverter are often higher in various applications of the inverter, so that the parallel technology of multiple inverters is gradually developed and matured. The multi-inverter parallel technology appears earlier in the parallel control of the UPS, and then appears in the fields of auxiliary power supply of trains and ships, new energy power generation and the like. With the wide access and large-scale application of new energy in recent years, the parallel technology of the distributed inverter is continuously developed and optimized, and meanwhile, the application occasions are wider, and the parallel technology is generally divided into a network construction type control mode and a network connection type control mode.
In the UPS field, the auxiliary power supply field, and the new energy power generation island mode, because no large grid provides voltage and frequency support, multiple inverter control often needs to face problems such as power equalization, current distribution, and circulating current. Currently, there are multiple parallel technical routes of multiple inverters, such as centralized control, master-slave control, distributed logic control, and non-interconnection control. The centralized control is composed of a parallel control unit and each inverter submodule, and the parallel control unit detects the total output current and divides the total output current by an average value to obtain a current instruction of each inverter submodule. When the frequency and phase deviation of the output voltage of each parallel unit is not large when the parallel units are controlled by a synchronous signal, the deviation of the current in each unit can be considered to be caused by the inconsistency of the voltage amplitude, so the control mode directly adds the current deviation as the compensation quantity of the voltage command to each inverter power supply unit to eliminate the unbalance of the current. However, the centralized control is excessively dependent on the centralized controller, the whole controller cannot work once a fault occurs, in addition, if the number of sub-modules is increased or decreased, great difficulty exists, and meanwhile, in order to ensure phase and frequency signals, the synchronous pulse height needs to be kept consistent, so that the requirement on communication is high, and the realization is difficult. In the master-slave control, the realization of current sharing is distributed to each submodule, wherein the master determines the voltage information and all the current information of the slave so as to realize the purpose of current sharing. Compared with centralized control, redundancy can be realized to a certain extent, reliability is improved, but the requirement of master-slave control on a host is high, and if the host fails, redundancy control still cannot be realized. The distributed logic control really realizes that each inverter power supply module does not depend on a centralized control unit or a certain main module, and can independently detect and control the working state of the module in the system to realize the reasonable distribution of the output power among the modules. The distributed logic parallel control technology is an independent parallel control mode, and adopts a control strategy of synthesizing current and frequency signals in each power module in each inverter to obtain compensation signals of respective frequency and voltage, so that the real N +1 parallel operation can be realized, and when one module is failed and quit, the parallel operation of other modules is not influenced, but the scheme has higher complexity and poorer practicability in practical engineering application.
At present, a multi-machine parallel control scheme based on no interconnection line is widely applied to engineering practice, and a good effect is achieved. The droop control is taken as a representative, and the characteristics of power averaging, plug and play and the like are well realized. In the droop control scheme, each inverter simulates the droop characteristic of the generator by detecting the output active power and reactive power of the inverter to adjust the amplitude and frequency of output voltage, and compared with the control scheme with an interconnection line, the droop control scheme is characterized in that a power control bus or an average current bus is not needed, the droop control scheme is easy to realize and is more practical.
With the rapid development of power electronic technology, the form of electric energy conversion is becoming more abundant. However, the non-linearity of the circuit is significantly enhanced due to the access of various inverters, rectifiers and other power conversion devices, so that the power quality of the power grid is greatly challenged. The traditional droop control mode is to calculate active power and reactive power according to voltage and current information in a fundamental wave range, and realize droop control in a fundamental wave domain. However, for the situation after the nonlinear load is connected, the generated harmonic cannot be cancelled by the droop control strategy based on the fundamental wave domain, so that the harmonic distortion of the grid-connected point is serious, and the power quality is affected.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method, a typical harmonic droop control link is added in a droop control scheme of the traditional fundamental wave domain range, and the voltage signal of a grid-connected point is acquired and subjected to FFT analysis by using a data sliding window mode to obtain the typical harmonic frequency and amplitude of the load side, so that the adaptive adjustment of the harmonic droop link of the harmonic domain is realized, the harmonic of the load side is counteracted in a targeted manner, and the purposes of suppressing the harmonic distortion of the grid-connected point and improving the electric energy quality are achieved. Therefore, one of the problems to be solved by the present invention is to introduce a harmonic domain frequency division droop control link on the basis of fundamental domain droop control, so as to achieve harmonic cancellation when a nonlinear load is accessed, improve the harmonic distortion condition on the load side, and improve the power quality. The invention also solves the problem that the directional frequency division droop control is realized by acquiring the harmonic information at the load side more conveniently and accurately by adopting a data sliding window and FFT analysis method.
The invention adopts the following technical scheme.
A frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method comprises the following steps:
step 1, collecting grid-connected point voltage and inverter side voltage and current;
step 2, acquiring and FFT analyzing the voltage signal of the grid-connected point by using a data sliding window mode according to the grid-connected point voltage acquired in the step 1 to obtain the typical harmonic frequency and amplitude of the load side and obtain a calculation result under fundamental waves;
step 3, obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the typical harmonic frequency and amplitude of the load side obtained in the step 2, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the calculation result under the fundamental wave obtained in the step 2;
and 4, according to the control parameters obtained in the step 3, respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control, superposing the obtained instruction values to realize the no-difference tracking of the voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, and implementing SPWM modulation through the SPWM modulation instruction value.
Preferably, the obtaining and FFT analysis of the voltage signal at the point of connection in the step 2 by using a data sliding window manner to obtain the typical harmonic frequency and amplitude at the load side specifically includes:
representing the voltage signal of the grid-connected point as the nth sampling sample as x n N is more than or equal to 0 and less than or equal to N-1, and N are positive integers, and Fourier transformation is carried out on the N sampling samples, which is shown in a formula (2):
Figure BDA0003878571130000031
wherein X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N The amplitude of the lower frequency, k is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency and amplitude of the load side, and the typical harmonic frequency of the load side is composed of all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
Preferably, the obtaining of the calculation result in the step 2 under the fundamental wave specifically includes:
according to the voltage and current at the side of the inverter, the method is used for information processing and coordinate transformation in a fundamental wave domain to obtain a calculation result in the fundamental wave domain; the information processing and coordinate transformation are used for performing three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the voltage and current of the inverter side, and are specifically expressed as formula (3-1) and formula (3-2):
Figure BDA0003878571130000041
Figure BDA0003878571130000042
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter side current b B-phase current, i, representing inverter-side current c The c-phase current representing the inverter-side current, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
Preferably, the step 3 of obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in the frequency-division droop control by using the typical harmonic frequency and amplitude of the load side obtained in the step 2 specifically includes:
obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control according to the formula (4):
Figure BDA0003878571130000043
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes, m, of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h h Frequency droop coefficient, n, corresponding to typical harmonic order h h The frequency droop coefficient corresponding to the typical harmonic order h.
Preferably, the step 3 of obtaining a calculation result under the fundamental wave by using the step 2, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control, specifically including;
the fundamental wave power is calculated by formula (5):
Figure BDA0003878571130000044
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current, u, on the d-axis and q-axis, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control are expressed as the following equations:
Figure BDA0003878571130000051
wherein i is the number of harmonics and is an integer of not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
Preferably, the step 4 of obtaining the command values according to the control parameters obtained in the step 3 through fundamental wave droop control and harmonic wave droop control respectively includes:
by the droop expression shown in the formula (6) under the condition of i =1, ω is obtained from the output power by the droop expression shown in the formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency command value and an amplitude command value of the output fundamental voltage; similarly, the harmonic droop is controlled to be at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain omega according to the output power n And E n At this time, ω n And E n Are respectively provided withThe frequency command value and the amplitude command value represent harmonic voltages.
A frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system comprises:
the acquisition module is used for acquiring the voltage of a grid connection point and the voltage and current of the inverter side;
the data sliding window and FFT analysis module is used for acquiring and FFT analyzing the voltage signal of the grid-connected point in a data sliding window mode according to the acquired grid-connected point voltage to obtain the typical harmonic frequency and amplitude of the load side and obtain a calculation result under fundamental waves;
the calculation module is used for obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the obtained typical harmonic frequency and amplitude of the load side, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the obtained calculation result under fundamental waves;
and the adjusting module is used for respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control according to the obtained control parameters, superposing the obtained instruction values to realize no-difference tracking of voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, and implementing SPWM modulation through the SPWM modulation instruction value.
Preferably, the data sliding window and FFT analysis module is further configured to represent the voltage signal of the grid-connected point as the nth sampling sample as x n N is more than or equal to 0 and less than or equal to N-1, and N are positive integers, and Fourier transformation is carried out on the N sampling samples, which is shown in a formula (2):
Figure BDA0003878571130000061
wherein X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N The amplitude of the lower frequency, k is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency sum of the load sideAmplitude, load side typical harmonic frequency from all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
Preferably, the data sliding window and FFT analysis module is further configured to perform information processing and coordinate transformation in a fundamental wave domain according to the inverter-side voltage and current to obtain a calculation result in the fundamental wave; the information processing and coordinate transformation are used for performing three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the voltage and current of the inverter side, and are specifically expressed as formula (3-1) and formula (3-2):
Figure BDA0003878571130000062
Figure BDA0003878571130000063
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter-side current b B-phase current, i, representing inverter-side current c The c-phase current of the inverter-side current is represented, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
Preferably, the calculating module is further configured to obtain control parameters such as a voltage droop coefficient and a frequency droop coefficient in the frequency droop control according to equation (4):
Figure BDA0003878571130000071
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes, m, of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h h Frequency droop coefficient, n, corresponding to typical harmonic order h h The frequency droop coefficient corresponding to the typical harmonic order h.
Preferably, the calculation module is further configured to calculate the fundamental power by equation (5):
Figure BDA0003878571130000072
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current, u, on the d-axis and q-axis, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control are expressed as the following equations:
Figure BDA0003878571130000073
wherein i is the number of harmonics and is an integer not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
Preferably, the adjusting module is further configured to obtain ω according to the output power by the droop expression shown in formula (6) under the condition of i =1 as shown in formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency command value and an amplitude command value of the output fundamental voltage; similarly, the harmonic droop is controlled to be at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain ω according to the output power n And E n At this time, ω n And E n Respectively representing the frequency command value and the amplitude command value of the harmonic voltage.
A terminal comprising a processor and a storage medium;
the storage medium is used for storing instructions;
the processor is configured to operate according to the instructions to perform the steps of the frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method.
Compared with the prior art, the method has the advantages that a typical harmonic frequency droop control link is added in a droop control scheme in the range of the traditional fundamental wave domain, the voltage signal of the grid-connected point is acquired and subjected to FFT analysis in a data sliding window mode, the typical harmonic frequency and the amplitude of the load side are obtained, the self-adaptive adjustment of the harmonic frequency droop link is realized, the harmonic wave of the load side is counteracted in a targeted manner, the method can realize the active sensing of the harmonic wave of the load side and the active adjustment of the frequency division droop control parameter, and the purposes of actively adapting to the load change, restraining the harmonic distortion of the grid-connected point and improving the electric energy quality are achieved.
Drawings
FIG. 1 is a schematic diagram of the practical operation of the inverter according to the present invention after the inverter is applied to the nonlinear load;
FIG. 2 is a schematic diagram of a frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression method according to the present invention;
FIG. 3 is a flow chart of a frequency adaptive multi-inverter parallel wide frequency domain load harmonic suppression method according to the present invention;
FIG. 4 is a block diagram of a frequency adaptive multi-inverter parallel wide frequency domain load harmonic suppression system according to the present invention;
in the figure: 1: a first inverter power supply device; 2: the nth inverter power supply device; 3: a grid connection point; 4: a rectifier-like nonlinear load; 5: nonlinear resistance and inductive load; 6: linear resistive and inductive loads; 7: an inverter power supply; 8: a filter capacitor; 9: a current sampling device; 10: a filter capacitor voltage sampling device; 11: and a grid connection point voltage sampling device.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described clearly and completely in the following with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described herein are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by a person skilled in the art without any inventive step based on the spirit of the present invention are within the scope of the present invention.
After a nonlinear load represented by a rectifying device, a nonlinear inductor, a resistor and the like is connected, the quality of electric energy on a network side (a load side) is deteriorated, harmonic distortion is serious, the quality of electric energy used by the device and the quality of electric energy used by other parallel-connected electric equipment are influenced, and even the safety of the equipment is damaged.
The invention relates to a frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method, which comprises the following steps as shown in fig. 2 and fig. 3:
step 1, collecting grid-connected point voltage and inverter side voltage and current;
specifically, in step 1, collecting a grid-connected point voltage and an inverter-side voltage and current includes: the current sampling device 9, the filter capacitor voltage sampling device 10 and the grid-connected point voltage sampling device 11 are respectively used for collecting the output current of the filter device, the capacitor voltage of the filter device and the voltage information of the load side; the output current of the filter means and the capacitor voltage of the filter means form the inverter-side voltage current. The filter capacitor voltage sampling device and the grid-connected point voltage sampling device can be mutual inductors or voltage sensors, and the current sampling device can be a current sensor.
Step 2, acquiring and carrying out FFT analysis on the voltage signal of the grid-connected point in a data sliding window mode according to the voltage of the grid-connected point acquired in the step 1 to obtain the typical harmonic frequency and amplitude of the load side and obtain a calculation result under fundamental waves;
in a preferred but non-limiting embodiment of the present invention, in step 2, the obtaining and FFT analysis of the voltage signal of the grid-connected point is performed by using a data sliding window manner, so as to obtain a typical harmonic frequency and amplitude at the load side, which specifically includes:
the voltage signal of the grid-connected point obtained by the data sliding window can be expressed as shown in formula (1) in the time domain:
Figure BDA0003878571130000091
wherein A is 0 Is the direct current component of the grid-connected point voltage signal;
Figure BDA0003878571130000092
is the fundamental frequency component of the grid-connected point voltage signal, which is called fundamental wave for short, omega is the fundamental frequency,
Figure BDA0003878571130000093
is a fundamental phasor;
Figure BDA0003878571130000094
is n-th harmonic of the grid-connected point voltage signal, n is a positive integer, A n For the nth harmonic amplitude of the grid-connected point voltage signal,
Figure BDA0003878571130000095
is an nth harmonic phasor;
in order to extract the harmonic amplitude and frequency, the harmonic amplitude and frequency need to be subjected to data processing through discrete Fourier transform, and the voltage signal of a grid-connected point as an nth sampling sample is assumed to be represented as x n Wherein N is greater than or equal to 0 and less than or equal to N-1 (i.e., N sampling samples are present), N and N are positive integers, and Fourier transform is performed on the N sampling samples, which is shown in formula (2):
Figure BDA0003878571130000096
wherein, X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N The amplitude of the lower frequency, k is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency and amplitude of the load side, and the typical harmonic frequency of the load side is composed of all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
Through the data processing process, the signal amplitude information under each frequency can be calculated according to the data obtained by the data sliding window.
In a preferred but non-limiting embodiment of the present invention, the obtaining of the calculation result in the step 2 under the fundamental wave specifically includes:
according to the voltage and current of the inverter side, the method is used for information processing and coordinate transformation in a fundamental wave domain to obtain a calculation result in the fundamental wave domain; the information processing and coordinate transformation are to perform three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the inverter-side voltage and current, and can be specifically expressed as shown in formula (3-1) and formula (3-2):
Figure BDA0003878571130000101
Figure BDA0003878571130000102
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter-side current b B-phase current, i, representing inverter-side current c The c-phase current representing the inverter-side current, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
Through the formula (3-1) and the formula (3-2), information of the voltage and the current under the fundamental wave in the dq coordinate system can be obtained.
In step 2, the data sliding window and FFT analysis means that data is sampled according to the voltage of the grid-connected point, the data sliding window is performed at a certain period to obtain a data frame beneficial to FFT analysis, and then the data frame is used as a sample to perform FFT analysis and obtain the network side harmonic frequency and amplitude information.
Step 3, obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the typical harmonic frequency and amplitude of the load side obtained in the step 2 so as to realize droop control of characteristic frequency in the following step, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the calculation result under the fundamental wave obtained in the step 2;
in a preferred but non-limiting embodiment of the present invention, the obtaining of the control parameters such as the voltage droop coefficient and the frequency droop coefficient in the frequency-division droop control by using the load-side typical harmonic frequency and amplitude obtained in step 2 in step 3 specifically includes:
obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control according to the formula (4):
Figure BDA0003878571130000111
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h, m h Frequency droop coefficient, n, corresponding to typical harmonic order h h The frequency droop coefficient corresponding to the typical harmonic order h.
In a preferred but non-limiting embodiment of the present invention, the step 3 of obtaining the calculation result under the fundamental wave by using the step 2, and performing the fundamental wave power calculation and the calculation of the active power-frequency control and the reactive power-voltage control, specifically including;
the fundamental power can be calculated by equation (5):
Figure BDA0003878571130000112
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current on the d-axis and on the q-axis, u, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control can be expressed as the following equations:
Figure BDA0003878571130000113
wherein i is the number of harmonics and is an integer not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
Specifically, active power-frequency control and reactive power-voltage control are key links of droop control, and the main purpose of the droop control method is to simulate the power transmission and distribution characteristics of a power grid so as to realize non-interconnection control.
And 4, according to the control parameters obtained in the step 3, respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control, superposing the obtained instruction values to realize the error-free tracking of voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, implementing SPWM modulation through the SPWM modulation instruction value, finally realizing the self-adaptive adjustment of a harmonic wave domain droop link, and counteracting the harmonic wave at the load side in a targeted manner.
In a preferred but non-limiting embodiment of the present invention, the obtaining of the command value according to the control parameter obtained in step 3 in step 4 through the fundamental wave droop control and the harmonic droop control respectively comprises:
the fundamental wave droop control is expressed by the formula (6) under the condition of i =1, and by this droop control, the grid power transmission characteristics can be simulated, and furthermore, the wireless control can be realized. By the droop expression shown in the formula (6) under the condition of i =1, ω can be obtained from the output power as shown in the formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency instruction value and an amplitude instruction value of the output fundamental voltage and serve as an instruction and a tracking target of subsequent double closed-loop control; similarly, the harmonic droop control can also be described by a similar formula, i.e., at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain omega according to the output power n And E n At this time, ω n And E n And the frequency instruction value and the amplitude instruction value respectively represent harmonic voltage and are used as an instruction and a tracking target of subsequent double closed-loop control.
Here, harmonic cancellation refers to: by detecting the harmonic content at the side of the power grid and according to the detected harmonic content, the frequency division droop control is used for sending out corresponding harmonic to compensate/offset the harmonic, and the function of controlling the power quality is achieved. The adaptive adjustment means: the invention can real-time detect harmonic content and real-time control frequency division and droop to compensate harmonic, so that the harmonic compensation effect can be adjusted in real time according to external changes, and the self-adaptive adjustment effect is achieved.
As shown in fig. 1, fig. 2 and fig. 4, the frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression system according to the present invention includes:
the acquisition module is used for acquiring the voltage of a grid connection point and the voltage and current of the inverter side;
specifically, the acquisition module comprises a filter capacitor voltage sampling device 10, a current sampling device 9 and a grid-connected point voltage sampling device 11; the filter capacitor voltage sampling device 10, the current sampling device 9 and the grid-connected point voltage sampling device 11 are electrically connected with the inverter power supply 7 of the load through the filter capacitor 8, and the current sampling device 9, the filter capacitor voltage sampling device 10 and the grid-connected point voltage sampling device 11 are respectively used for collecting the output current of the filter device, the capacitor voltage of the filter device and the voltage information of the load side; an inverter power supply 7 electrically connected to the filter capacitor 8 and the load is formed as an inverter power supply apparatus of the first inverter power supply apparatus 1.. N. The inverter power supply 7 is electrically connected to the load through the interconnection point 3, and the load includes a rectifier-type nonlinear load 4, a nonlinear resistor and inductor load 5, and a linear resistor and inductor load 6.
The data sliding window and FFT analysis module is used for acquiring and FFT analyzing the voltage signal of the grid-connected point in a data sliding window mode according to the acquired grid-connected point voltage to obtain the typical harmonic frequency and amplitude of the load side and obtain a calculation result under fundamental waves;
the calculation module is used for obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the obtained typical harmonic frequency and amplitude of the load side so as to realize droop control of characteristic frequency in the subsequent process, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the obtained calculation result under fundamental waves;
and the adjusting module is used for respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control according to the obtained control parameters, superposing the obtained instruction values to realize the non-difference tracking of voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, implementing SPWM modulation through the SPWM modulation instruction value, finally realizing the self-adaptive adjustment of a harmonic wave domain droop link, and pertinently offsetting the harmonic wave at the load side.
In a preferred but non-limiting embodiment of the present invention, the data sliding window and FFT analysis module is further configured to represent the grid-connected point voltage signal as the nth sample as x n Wherein N is greater than or equal to 0 and less than or equal to N-1 (i.e., N sampling samples are present), N and N are positive integers, and Fourier transform is performed on the N sampling samples, which is shown in formula (2):
Figure BDA0003878571130000131
wherein, X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N K is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency and amplitude of the load side, and the typical harmonic frequency of the load side is composed of all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
In a preferred but non-limiting embodiment of the present invention, the data sliding window and FFT analysis module is further configured to perform information processing and coordinate transformation in the fundamental wave domain according to the inverter-side voltage and current to obtain a calculation result in the fundamental wave; the information processing and coordinate transformation are to perform three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the voltage and current of the inverter side, and can be specifically expressed as shown in formula (3-1) and formula (3-2):
Figure BDA0003878571130000132
Figure BDA0003878571130000141
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter-side current b B-phase current, i, representing inverter-side current c The c-phase current representing the inverter-side current, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
In a preferred but non-limiting embodiment of the present invention, the calculating module is further configured to obtain control parameters such as a voltage droop coefficient and a frequency droop coefficient in the frequency division droop control according to equation (4):
Figure BDA0003878571130000142
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes, m, of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h h Frequency droop coefficient, n, corresponding to typical harmonic order h h The frequency droop coefficient corresponds to the typical harmonic order h.
In a preferred but non-limiting embodiment of the invention, the calculation module is further configured to calculate the fundamental power by equation (5):
Figure BDA0003878571130000143
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current on the d-axis and on the q-axis, u, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control can be expressed as the following equations:
Figure BDA0003878571130000144
wherein i is the number of harmonics and is an integer of not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
In a preferred but non-limiting embodiment of the present invention, the adjusting module is further configured to be represented by formula (6) under the condition that the fundamental wave droop control is i =1, and through the droop control, the grid transmission characteristic can be simulated, so as to realize the wireless internet control. By the droop expression shown in the formula (6) under the condition of i =1, ω can be obtained from the output power as shown in the formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency instruction value and an amplitude instruction value of the output fundamental voltage and serve as an instruction and a tracking target of subsequent double closed-loop control; similarly, the harmonic droop control can also be described by a similar formula, i.e., at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain ω according to the output power n And E n At this time, ω n And E n And the frequency instruction value and the amplitude instruction value respectively represent harmonic voltage and are used as an instruction and a tracking target of subsequent double closed-loop control.
A terminal comprising a processor and a storage medium;
the storage medium is used for storing instructions;
the processor is configured to operate according to the instructions to perform the steps of the frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method.
A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the frequency adaptive multi-inverter parallel wide frequency domain load harmonic suppression method.
The present disclosure may be systems, methods, and/or computer program products. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to implement various aspects of the present disclosure.
The computer-readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be interpreted as a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or an electrical signal transmitted through an electrical wire.
The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device via a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.
The computer program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, the electronic circuitry that can execute the computer-readable program instructions implements aspects of the present disclosure by utilizing the state information of the computer-readable program instructions to personalize the electronic circuitry, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA).
Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.
These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer-readable medium storing the instructions comprises an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (14)

1. A frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method is characterized by comprising the following steps:
step 1, collecting grid-connected point voltage and inverter side voltage and current;
step 2, acquiring and carrying out FFT analysis on the voltage signal of the grid-connected point in a data sliding window mode according to the voltage of the grid-connected point acquired in the step 1 to obtain the typical harmonic frequency and amplitude of the load side and obtain a calculation result under fundamental waves;
step 3, obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the typical harmonic frequency and amplitude of the load side obtained in the step 2, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the calculation result under the fundamental wave obtained in the step 2;
and 4, according to the control parameters obtained in the step 3, respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control, superposing the obtained instruction values to realize the no-difference tracking of the voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, and implementing SPWM modulation through the SPWM modulation instruction value.
2. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method according to claim 1, wherein the step 2 of obtaining and FFT analyzing the voltage signal at the point of connection by using a data sliding window manner to obtain a typical harmonic frequency and amplitude at the load side specifically comprises:
representing the grid-connected point voltage signal as the nth sample as x n N is more than or equal to 0 and less than or equal to N-1, and N are positive integers, and Fourier transformation is carried out on the N sampling samples, which is shown in a formula (2):
Figure FDA0003878571120000011
wherein, X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N K is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency and amplitude of the load side, and the typical harmonic frequency of the load side is composed of all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
3. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression method according to claim 1, wherein the obtaining of the calculation result under the fundamental wave in the step 2 specifically includes:
according to the voltage and current of the inverter side, the method is used for information processing and coordinate transformation in a fundamental wave domain to obtain a calculation result in the fundamental wave domain; the information processing and coordinate transformation refers to performing three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the voltage and current of the inverter side, and is specifically expressed as formula (3-1) and formula (3-2):
Figure FDA0003878571120000021
Figure FDA0003878571120000022
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter side current b B-phase current, i, representing inverter-side current c The c-phase current of the inverter-side current is represented, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
4. The method for suppressing the frequency-adaptive multi-inverter parallel wide frequency domain load harmonics according to claim 1, wherein the step 3 of obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in the frequency division droop control by using the load-side typical harmonic frequency and amplitude obtained in the step 2 specifically comprises:
obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control according to the formula (4):
Figure FDA0003878571120000023
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h, m h Frequency droop coefficient, n, corresponding to typical harmonic order h h The frequency droop coefficient corresponding to the typical harmonic order h.
5. The method for suppressing the load harmonics in the frequency-adaptive multi-inverter parallel wide frequency domain according to claim 1, wherein the step 3 includes obtaining the calculation result in the fundamental wave by using the step 2, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control, specifically including;
the fundamental wave power is calculated by formula (5):
Figure FDA0003878571120000031
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current, u, on the d-axis and q-axis, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control are expressed as the following equations:
Figure FDA0003878571120000032
wherein i is the number of harmonics and is an integer of not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
6. The method for suppressing the harmonic waves of the frequency-adaptive multi-inverter parallel wide frequency domain load according to claim 5, wherein the step 4 of obtaining the command values through the fundamental wave droop control and the harmonic droop control according to the control parameters obtained in the step 3 comprises:
by the droop expression shown in the formula (6) under the condition of i =1, ω is obtained from the output power by the droop expression shown in the formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency command value and an amplitude command value of the output fundamental voltage; similarly, the harmonic droop is controlled to be at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain omega according to the output power n And E n At this time, ω n And E n Respectively representing the frequency command value and the amplitude command value of the harmonic voltage.
7. A frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system is characterized by comprising:
the acquisition module is used for acquiring the voltage of a grid connection point and the voltage and current of the inverter side;
the data sliding window and FFT analysis module is used for acquiring and FFT analyzing voltage signals of grid-connected points in a data sliding window mode according to the acquired grid-connected point voltages to obtain typical harmonic frequency and amplitude of a load side and obtain a calculation result under fundamental waves;
the calculation module is used for obtaining control parameters such as a voltage droop coefficient and a frequency droop coefficient in frequency division droop control by using the obtained typical harmonic frequency and amplitude of the load side, and performing fundamental wave power calculation and calculation of active power-frequency control and reactive power-voltage control by using the obtained calculation result under fundamental waves;
and the adjusting module is used for respectively obtaining instruction values through fundamental wave droop control and harmonic wave droop control according to the obtained control parameters, superposing the obtained instruction values to realize no-difference tracking of voltage and current instructions, obtaining an SPWM modulation instruction value after superposition, and implementing SPWM modulation through the SPWM modulation instruction value.
8. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system according to claim 7, wherein the data sliding window and FFT analysis module is further configured to represent a grid-connected point voltage signal as an nth sample as x n N is more than or equal to 0 and less than or equal to N-1, and N are positive integers, and Fourier transformation is carried out on the N sampling samples, which is shown in a formula (2):
Figure FDA0003878571120000041
wherein X k Is x n Corresponding frequency domain representation, x n Numerically representing the corresponding frequency e -j2πkn/N K is an integer between 0 and N-1, thereby obtaining the typical harmonic frequency and amplitude of the load side, and the typical harmonic frequency of the load side is composed of all e -j2πkn/N The amplitude of the typical harmonic on the load side is composed of all x n The amplitude value is formed.
9. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system according to claim 7, wherein the data sliding window and FFT analysis module is further configured to obtain a calculation result in the fundamental wave according to the inverter-side voltage and current for information processing and coordinate transformation in the fundamental wave domain; the information processing and coordinate transformation are used for performing three-phase rotating coordinate system-two-phase stationary coordinate system transformation on the voltage and current of the inverter side, and are specifically expressed as formula (3-1) and formula (3-2):
Figure FDA0003878571120000042
Figure FDA0003878571120000043
wherein v is a A-phase voltage, v, representing the inverter-side voltage b B-phase voltage, v, representing the inverter-side voltage c C-phase voltage i representing inverter-side voltage a Phase a current, i, representing the inverter-side current b B-phase current, i, representing inverter-side current c The c-phase current representing the inverter-side current, the left side of equation (3-1) represents the conversion result in the two-phase stationary coordinate system of the inverter-side voltage, and the left side of equation (3-2) represents the conversion result in the two-phase stationary coordinate system of the inverter-side current.
10. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system according to claim 7, wherein the calculation module is further configured to obtain control parameters such as a voltage droop coefficient and a frequency droop coefficient in the frequency-division droop control according to equation (4):
Figure FDA0003878571120000051
wherein, ω is n Is the fundamental frequency, omega, in the grid-connected point voltage signal h Is the typical harmonic frequency of the load side, h is the corresponding typical harmonic order, P h 、Q h And E h The amplitudes, m, of the load side harmonic active power, the load side harmonic reactive power and the load side typical harmonic corresponding to the typical harmonic order h h Is a typical harmonic orderFrequency droop coefficient, n, corresponding to the number h h The frequency droop coefficient corresponding to the typical harmonic order h.
11. The frequency-adaptive multi-inverter parallel wide frequency domain load harmonic suppression system according to claim 7, wherein the calculation module is further configured to calculate the fundamental power according to formula (5):
Figure FDA0003878571120000052
wherein u is od 、i od 、u oq 、i oq Representing the components of the output voltage and output current, u, on the d-axis and q-axis, respectively od ＝U 0 -U d ，i od ＝I 0 -I d ，u oq ＝U 0 -U q ，i oq ＝I 0 -I q ；
The active power-frequency control and the reactive power-voltage control can be expressed as the following equations:
Figure FDA0003878571120000053
wherein i is the number of harmonics and is an integer of not less than 1, ω n ＝ω 0 -m i P denotes active power-frequency control, E n ＝E 0 -n i Q o Representing reactive power-voltage control.
12. The frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression system according to claim 11, wherein the adjusting module is further configured to obtain ω from the output power by the droop expression shown in formula (6) under i =1 under the condition of i =1 as shown in formula (6) under the condition of i =1 n And E n The two variables are respectively a frequency command value and an amplitude command value of the output fundamental voltage; for the same reason, harmonic droop controlIs at i>1, as shown in formula (6), by adding a catalyst in the presence of i>The droop expression shown in formula (6) under the condition of 1 can obtain ω according to the output power n And E n At this time, ω n And E n Respectively representing the frequency command value and the amplitude command value of the harmonic voltage.
13. A terminal comprising a processor and a storage medium; the method is characterized in that:
the storage medium is to store instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the frequency adaptive multiple inverter parallel wide frequency domain load harmonic suppression method according to any of claims 1-6.
14. Computer readable storage medium, having stored thereon a computer program, characterized in that the program, when being executed by a processor, is adapted to carry out the steps of the frequency adaptive multi-inverter parallel wide frequency domain load harmonic suppression method according to any of the claims 1-6.
CN202211222340.XA 2022-10-08 2022-10-08 Frequency-adaptive multi-inverter parallel wide-frequency-domain load harmonic suppression method Pending CN115622059A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
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CN117096938A (en) * 2023-10-19 2023-11-21 国网浙江省电力有限公司象山县供电公司 Inverter output power quality adaptive control method and device and computer equipment

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117096938A (en) * 2023-10-19 2023-11-21 国网浙江省电力有限公司象山县供电公司 Inverter output power quality adaptive control method and device and computer equipment
CN117096938B (en) * 2023-10-19 2024-03-12 国网浙江省电力有限公司象山县供电公司 Inverter output power quality adaptive control method and device and computer equipment

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