CN116827096A - Inverter and control method thereof, photovoltaic system, energy storage device and storage medium - Google Patents

Inverter and control method thereof, photovoltaic system, energy storage device and storage medium Download PDF

Info

Publication number
CN116827096A
CN116827096A CN202310769183.2A CN202310769183A CN116827096A CN 116827096 A CN116827096 A CN 116827096A CN 202310769183 A CN202310769183 A CN 202310769183A CN 116827096 A CN116827096 A CN 116827096A
Authority
CN
China
Prior art keywords
current
inverter
output
given
zero crossing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310769183.2A
Other languages
Chinese (zh)
Inventor
尹家伟
张宏韬
陈熙
王雷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ecoflow Technology Ltd
Original Assignee
Ecoflow Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ecoflow Technology Ltd filed Critical Ecoflow Technology Ltd
Priority to CN202310769183.2A priority Critical patent/CN116827096A/en
Publication of CN116827096A publication Critical patent/CN116827096A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • H02J15/00—Systems for storing electric energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/30—Electrical components
    • H02S40/32—Electrical components comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The application provides an inverter, a control method thereof, a photovoltaic system, energy storage equipment and a storage medium. The control method comprises the following steps: acquiring the actual output current of the inverter; filtering the actual output current to obtain a given current; detecting zero crossing points of the given current, and determining a repeated control period according to the zero crossing points of the given current; and in each repeated control period, performing repeated control calculation according to the given current and the output sampling current of the inverter to generate a driving signal to the inverter, wherein the driving signal is used for controlling the on-off of a switching tube in the inverter. The control method of the inverter provided by the application can reduce the occurrence of failure of the repetitive controller caused by phase sliding.

Description

Inverter and control method thereof, photovoltaic system, energy storage device and storage medium
Technical Field
The present application relates to the field of power electronic control technologies, and in particular, to an inverter, a control method thereof, a photovoltaic system, an energy storage device, and a storage medium.
Background
The repeated control algorithm is a control algorithm based on the internal model principle and has very wide application. For example, in distributed grid-connected current control, a repetitive controller is often used to participate in the process of converting dc power by an inverter to output ac power.
However, in the related art, since the output of the inverter varies, when the inverter is controlled by the repetitive controller, the phase of the alternating current output from the inverter is liable to be advanced or retarded, thereby affecting the correction result. And errors due to phase lead or lag are continuously amplified due to time accumulation.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a control method of an inverter, a photovoltaic system, an energy storage device, and a storage medium, so as to reduce errors occurring due to phase slip during repetitive control.
The first aspect of the present application provides a control method of an inverter, where the inverter is configured to convert an input dc power and output an ac power. The control method comprises the following steps: acquiring the actual output current of the inverter; filtering the actual output current to obtain a given current; detecting zero crossing points of the given current, and determining a repeated control period according to the zero crossing points of the given current; and in each repeated control period, performing repeated control calculation according to the given current and the output sampling current of the inverter to generate a driving signal to the inverter, wherein the driving signal is used for controlling the on-off of a switching tube in the inverter.
In one embodiment, determining the repetition control period from the zero crossing of a given current includes: sequentially acquiring a first zero crossing point, a second zero crossing point and a third zero crossing point of a given current; when the current directions of the first zero crossing point and the second zero crossing point are opposite, and the current directions of the second zero crossing point and the third zero crossing point are opposite, the first zero crossing point is determined to be the starting point of the repeated control period, and the third zero crossing point is determined to be the end point of the repeated control period.
In one embodiment, filtering the actual output current includes: SOGI filtering is carried out on the actual output current to obtain a given reference current; SOGI filtering is performed on a given reference current to obtain a given current.
In one embodiment, performing a repetitive control calculation based on a given current and an output sampling current of an inverter to generate a drive signal to the inverter includes: generating a corresponding current deviation value according to the given current and the output sampling current of the inverter; calculating a target duty cycle according to the current deviation value and the given current; a drive signal is generated according to the target duty cycle.
In one embodiment, calculating the target duty cycle from the current bias value and the given current includes: performing repeated control processing on the current deviation value to obtain a first compensation component; differentiating the given current to obtain a second compensation component; acquiring the actual output voltage and the actual input voltage of the inverter; determining an output duty cycle compensation value according to the first compensation component, the second compensation component and the output sampling current of the inverter; and calculating the target duty ratio according to the actual input voltage, the actual output voltage and the output duty ratio compensation value.
In one embodiment, determining an output duty cycle compensation value from the first compensation component, the second compensation component, and an output sampling current of the inverter includes: and the sum of the first compensation component and the second compensation component is subjected to difference with the output sampling current of the inverter to obtain an output duty cycle compensation value.
The second aspect of the application also provides an inverter comprising an inverter circuit and a controller. The input end of the inverter circuit is used for receiving direct current, and the output end of the inverter circuit is used for outputting alternating current. The controller is configured to execute the control method of the inverter according to any one of the above.
The third aspect of the application also provides a photovoltaic system comprising a photovoltaic module and an inverter as described above. The output end of the photovoltaic module is electrically connected to the input end of the inverter. The inverter is used for converting direct current output by the photovoltaic module into alternating current and outputting the alternating current.
The fourth aspect of the present application also provides an energy storage device, including a battery module and the inverter described above. The output end of the battery module is electrically connected to the input end of the inverter. The inverter is used for converting direct current output by the battery module into alternating current and outputting the alternating current.
The fifth aspect of the present application also provides a computer-readable storage medium storing a computer program. The computer program, when executed by a processor, causes the processor to implement the method for controlling an inverter according to any one of the above.
According to the control method of the inverter, the actual output current of the inverter is subjected to filtering treatment, zero crossing point detection is carried out on the current obtained through the filtering treatment, and the repeated control period is confirmed according to the zero crossing point. And further performing repetitive control calculation in each repetitive control period to generate a driving signal to the inverter. Thus, the control method of the inverter provided by the application can reduce the occurrence of the failure of the repetitive controller caused by phase sliding.
Drawings
In order to more clearly illustrate the technical solutions of the present application, the drawings that are required for the embodiments will be briefly described, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application. Like elements are numbered alike in the various figures.
Fig. 1 is a circuit block diagram of an inverter according to an embodiment of the present application.
Fig. 2 is a circuit diagram of an inverter according to an embodiment of the application.
Fig. 3 is a flowchart illustrating a control method of an inverter according to an embodiment of the application.
Fig. 4 is a schematic diagram of a repetitive control cycle according to an embodiment of the present application.
Fig. 5 is a schematic flow chart of the substeps of step S302 according to an embodiment of the application.
Fig. 6 is a schematic diagram of performing SOGI filtering twice on an actual output current according to an embodiment of the present application.
FIG. 7 is a waveform diagram of an actual output current, a given reference current, and a given current according to an embodiment of the present application.
Fig. 8 is a flowchart illustrating the substep of step S304 according to an embodiment of the application.
Fig. 9 is a schematic flow chart of the substeps of step S802 in an embodiment of the application.
Fig. 10 is a control block diagram of a control method of an inverter according to an embodiment of the application.
Fig. 11 is a control block diagram of a control method of an inverter according to another embodiment of the present application.
Fig. 12 is a block diagram of an inverter according to an embodiment of the present application.
Fig. 13 is a block diagram of a photovoltaic system according to an embodiment of the present application.
Fig. 14 is a block diagram of an energy storage device according to an embodiment of the present application.
Fig. 15 is a block diagram of a control device according to an embodiment of the present application.
Detailed Description
The following description of the technical solutions according to the embodiments of the present application will be given with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments.
It is noted that when one component is considered to be "connected" to another component, it may be directly connected to the other component or intervening components may also be present. When an element is referred to as being "disposed" on another element, it can be directly on the other element or intervening elements may also be present. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "rear," and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
Some embodiments will be described below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.
The repeated control algorithm is a control algorithm based on the internal model principle and has very wide application. For example, in distributed grid-connected current control, a repetitive controller is often used to participate in the process of converting dc power by an inverter to output ac power. However, in the related art, since the output of the inverter varies, when the inverter is controlled by the repetitive controller, the phase of the alternating current output from the inverter is liable to be advanced or retarded, thereby affecting the correction result. And errors due to phase lead or lag are continuously amplified due to time accumulation.
Based on the above, the application provides a control method of an inverter, so as to reduce errors caused by phase slip of alternating current output by the inverter in the repeated control process.
Referring to fig. 1, fig. 1 is a circuit block diagram of an inverter 10 to which the control method of the present application is applied. The input of the inverter 10 is connected to the power supply device 20 via dc buses (including a positive dc BUS bus+ and a negative dc BUS-). The inverter 10 converts the dc power input from the power supply device 20, and outputs ac power to the ac load 30. Understandably, the power supply apparatus 20 includes, but is not limited to, an electronic apparatus or device for outputting direct current, such as a battery module, a photovoltaic module, and the like.
With continued reference to fig. 2, in some embodiments, the inverter 10 includes a switching tube Q1, a switching tube Q2, a switching tube Q3, a switching tube Q4, an inductor L, and a first capacitor C1. The first end of the switching tube Q1 and the first end of the switching tube Q2 are electrically connected to the positive dc BUS bus+. The second terminal of the switching tube Q1 is electrically connected to the first terminal of the switching tube Q3. The second terminal of the switching tube Q2 is electrically connected to the first terminal of the switching tube Q4. The second end of the switching tube Q3 and the second end of the switching tube Q4 are electrically connected to the negative DC BUS BUS-. The first end of the inductor L1 is electrically connected between the second end of the switching tube Q1 and the first end of the switching tube Q3. The second terminal of the inductor L1 is electrically connected to the first terminal of the first capacitor C1. The second terminal of the first capacitor C1 is electrically connected between the second terminal of the switching tube Q2 and the first terminal of the switching tube Q4. The positive output out+ of the inverter 10 is electrically connected between the inductor L1 and the first end of the first capacitor C1, and the negative output OUT-of the inverter 10 is electrically connected between the second end of the first capacitor C1 and the first end of the switching tube Q4. A second capacitor C2 is also connected between the positive DC BUS BUS+ and the negative DC BUS BUS-.
It can be understood that the inverter 10 can be controlled to convert dc power into ac power by controlling the switching logic and duty cycle of the switching transistors Q1, Q2, Q3 and Q4.
In other embodiments, the inverter may also be other existing inverter circuits, and the present application is not limited to the specific circuit of the inverter.
With continued reference to fig. 3, fig. 3 is a flowchart illustrating a control method of an inverter according to an embodiment of the application. And the control method is applied to a controller (not shown) of the inverter 10. The control method comprises the following steps:
step S301: the actual output current of the inverter is obtained.
In step S301, the current across the first capacitor C1 may be obtained by the current detection device, thereby obtaining the actual output current of the inverter.
It is understood that the dc power on the dc bus is processed by the inverter, and the magnitude and direction of the dc power are periodically changed, and a periodic ac power signal is formed. The period of the ac signal output by the inverter is short, and the switching logic and duty ratio of the switching transistors Q1, Q2, Q3, and Q4 can be controlled to adjust the period.
Step S302: the actual output current is filtered to obtain a given current.
Understandably, the actual output current is a complex periodic oscillation prior to untreated. The sine wave component equal to the longest period of the oscillation is the fundamental wave of the actual output current, and the frequency corresponding to the longest period is called the fundamental frequency; the sine wave component having a frequency equal to an integer multiple of the fundamental frequency is called a harmonic. Due to the problems of circuit disturbance, control delay, etc., in step S301, the untreated actual output current carries more harmonics, and the current may not be continuous. Thus, the waveform of the actual output current is not a pure sine wave at this time.
The possibility of the overload damage of the load 30 can be better reduced because the sine wave alternating current changes smoothly; also, in the related art, a large number of non-sinusoidal periodic signals can be decomposed into sinusoidal components of different frequencies by fourier series. In this way, if the waveform of the output current of the inverter 10 is a sine wave, the output current can be conveniently raised or lowered based on the fourier series later.
Therefore, in step S302, the actual output current is filtered to remove most of the harmonics in the actual output current to preserve the fundamental wave, thereby obtaining a given current with a waveform closer to a sine wave. As such, the given current obtained in step S302 may also be regarded as an ideal output current of the inverter 10.
In step S302, at least one cycle of the actual output current is processed to obtain a given current for at least one complete cycle, and the waveform of the given current is a sine wave. In other embodiments, the waveform of a given current is not limited to a sine wave.
Step S303: and detecting zero crossing points of the given current, and determining repeated control periods according to the zero crossing points of the given current.
In step S303, the repetition control period refers to a fundamental period of the actual output current, that is, a period of the given current. It is understood that for a periodic ac signal, the start and end points of each period are at zero crossings. In this way, the zero crossing point of the given current is detected, and the starting point and the end point of each period of the given current can be further determined, so that the period of the given current, that is, the repeated control period, is determined.
It will be appreciated that in other embodiments, the repetition control period may also be determined by zero crossing detection of the filtered actual output voltage. The repeated control period determined based on the actual output voltage is the fundamental wave period of the actual output voltage.
Step S304: and in each repeated control period, performing repeated control calculation according to the given current and the output sampling current of the inverter to generate a driving signal to the inverter, wherein the driving signal is used for controlling the on-off of a switching tube in the inverter.
The output sampling current of the inverter is a current obtained by sampling the output current of the inverter.
In step S304, a repetitive control algorithm is employed to suppress harmonics in the actual output current of the inverter, thereby bringing the actual output current close to a given current. The principle of the repetitive control is that, assuming that the fundamental waveform distortion occurring in the previous cycle will occur repeatedly at the same time in the next cycle, the repetitive controller determines a required correction signal based on the error of a given signal (for example, the given current in step S302) and a feedback signal (for example, the output sampling current of the inverter), and then superimposes this signal on the original control signal at the same time in the next fundamental cycle to eliminate the repetitive distortion that will occur in the following cycles.
With the fundamental period of the output current of the inverter as T P The sampling period of the repeated control is T S For example, then, the repetitive controller repeats every fundamental period T P And internally sampling the output current of the inverter to calculate an error according to the sampling result of the output current of the inverter and the sampling result of the given current at the same phase point, so as to control the switching logic or the duty ratio of the switching tube according to the error to correct the output current of the inverter, thereby enabling the actual output current to be closer to the given current. Wherein each fundamental period T P The sampling times N in the inner part are T P /T S . And the repeated control has strong dependence on the fundamental wave period sampling point number N. Ideally, if the fundamental wave is sampled periodicallyThe number N is fixed, so that the repetitive controller can stably output, and an ideal filtering effect is achieved. However, in the actual operation state, due to internal or external disturbance of the inverter 10, delay of the electric signal, etc., the fundamental period T of the output current P Is subject to fluctuation. At this time, if the original fundamental wave period T is adopted P The calculated number of samples N is sampled and the deviation between the obtained given current and the output sampled current is actually an error due to the phase slip, e.g. lead or lag, of the alternating current output by the inverter. Further, due to accumulation of time, errors generated by phase lead or lag are accumulated continuously, thereby affecting the filtering effect on the actual output current of the inverter 10.
In this way, in step S304 of the present application, in order to reduce the error caused by the phase slip, based on the repetition control period determined in step S303, the repetition control calculation is performed at the start point of the repetition control period, based on the output sampling current of the inverter and the sampling result of the given current, until the end point of the repetition control period ends the calculation in the current repetition control period. Further, in step S304, a driving signal is generated according to the result of the repetitive control calculation to control the switching logic and the duty ratio of the switching transistors Q1, Q2, Q3, and Q4 in the inverter, so that the inverter 10 stably outputs an actual output current close to the predetermined current.
In some embodiments, the output sampling current and the given current of the inverter may be sampled according to a preset sampling number to obtain a sampling result. As can be appreciated, since the time length of the actual repetitive control period is very short, and the variation amplitude of the repetitive control period is small (the fundamental frequency of the actual output current is usually within 5 Hz), in the present application, the actual output current and the given current are sampled for a preset number of times in each repetitive control period, so that on one hand, the deviation between the actual output current and the given current can be corrected more accurately; on the other hand, even when the frequency of the actual output current changes so that the repetition control period changes, since the end of the repetition control period is detected, the current repetition control calculation is immediately stopped. Thus, errors are not accumulated due to phase slip. Therefore, the error generated by the phase slip can be reduced by performing step S304.
In some embodiments, the preset number of samples may be obtained from multiple sets of laboratory data for the inverter. In other embodiments, the preset sampling times can be adjusted correspondingly according to the periodic variation of the actual output current, so as to further improve the correction accuracy of the repetitive control.
In this way, in step S304, by determining the repetition control period, the repetition control calculation is performed in the current repetition control period, and the repetition control calculation in the current repetition control period is ended when the end of the repetition control period is detected, thereby reducing the error due to the phase slip.
In summary, according to the control method of the inverter provided by the application, the actual output current of the inverter 10 is subjected to zero crossing detection, so that the repeated control period is confirmed according to the zero crossing. And further performs repetitive control calculation in each repetitive control period to generate a driving signal to the inverter 10. Thus, the control method of the inverter provided by the application can reduce errors caused by repeated control of the inverter due to phase slip caused by unstable actual output current period.
In some embodiments, determining the repetition control period from the zero crossing of the given current in step S303 comprises:
and sequentially acquiring a first zero crossing point, a second zero crossing point and a third zero crossing point of the given current, and determining the first zero crossing point as a starting point of a repeated control period and determining the third zero crossing point as an end point of the repeated control period when the current directions of the first zero crossing point and the second zero crossing point are opposite and the current directions of the second zero crossing point and the third zero crossing point are the same.
For example, referring to fig. 4, in fig. 4, a first zero-crossing point k1, a second zero-crossing point k2, and a third zero-crossing point k3 exist for a given current Iref. Wherein, the direction of the current at the first zero crossing point k1 is opposite to the direction of the current at the second zero crossing point k2, and the direction of the current at the second zero crossing point k2 is opposite to the direction of the current at the third zero crossing point k3, then the first zero crossing point k1 can be considered as the start point of the repetitive control period, and the third zero crossing point k3 is the end point of the repetitive control period. In this way, the presence of the repetition control period T1 can be confirmed.
Further, in the next detection period, the third zero-crossing point k3 is taken as the first zero-crossing point k1, and then zero-crossing point detection is continued to determine another repetitive control period.
It will be appreciated that in some embodiments zero crossing detection may be achieved by comparing the sampled current with a reference current (e.g., zero current) or using existing zero detection circuitry or sensors. The application is not limited to a specific method of zero crossing detection.
Referring to fig. 5, in some embodiments, step S302 includes the following sub-steps:
step S501: the actual output current is SOGI filtered to obtain a given reference current.
Understandably, a Second Order Generalized Integrator (SOGI) can be used to filter out higher harmonics. Wherein, the transfer function of SOGI is:
where K is a damping coefficient, s is a laplace operator, wn is a fundamental angular frequency, that is, when the fundamental frequency of the actual output current is f, the fundamental angular frequency is 2pi_f.
In this way, the harmonic component in the actual output current can be primarily attenuated by the given reference current obtained by SOGI filtering the actual output current.
Step S502: SOGI filtering is performed on a given reference current to obtain a given current.
Further, in step S502, SOGI filtering is continued on the given reference current to filter out harmonic components again, thereby obtaining a given current that is closer to a sine wave.
Specifically, referring to fig. 6, fig. 6 is a schematic diagram of performing SOGI filtering twice on the actual output current in step S501 and step S502. As can be seen from FIG. 6After 2 times of SOGI filtering, the actual output current I of the application is multiplied by the corresponding coefficient I refcoef A given current I can be obtained ref 。
In fig. 7, a curve P71 is a waveform of an actual output current, a curve P72 is a waveform of a given reference current, and a curve P73 is a waveform of a given current. As is apparent from fig. 7, the two SOGI filtering processes of step S501 and step S502 on the actual output current can filter the harmonic wave of the actual output current, and simultaneously reduce the harmonic interference of the actual output current as much as possible, which is more beneficial to the adjustment of the actual output current.
It will be appreciated that in other embodiments, other filtering methods may be used to process the actual output current to filter out harmonic components in the actual output current, and the present application is not limited to a specific filtering method.
Referring to fig. 8, in some embodiments, step S304 includes the following sub-steps:
step S801: and generating a corresponding current deviation value according to the given current and the output sampling current of the inverter.
It will be appreciated that in some embodiments, when the start point of the repetitive control period is detected, the given current and the output sampling current of the inverter are sampled a preset number of times until the end point of the repetitive control period stops sampling. Thus, a difference obtained by subtracting the output sampling current of the inverter from the given current of the corresponding sampling point is calculated as a current deviation value.
Step S802: and calculating the target duty ratio according to the current deviation value and the given current.
It is understood that the current offset value is used to characterize the gap between the output sampling current of the inverter and a given current. In step S802, the actual output current of the inverter 10 may be corrected based on the calculated target duty ratio of the current deviation value.
Step S803: a drive signal is generated according to the target duty cycle.
As can be appreciated, the drive signal of the inverter 10 is typically a PWM (Pulse Width Modulation, pulse width modulated) signal. The target duty ratio calculated in step S802 is the duty ratio of the generated driving signal. In this way, the inverter 10 is turned on according to the driving signal of the target duty ratio, so that it stably outputs an actual output current close to a given current.
With continued reference to fig. 9, in some embodiments, step S802 includes the following sub-steps:
step S901: and carrying out repeated control processing on the current deviation value to obtain a first compensation component.
In step S901, a repetitive control process is performed on the current deviation value based on the repetitive control algorithm to obtain a first compensation component. Specifically, the current deviation value may be processed by the repetitive control unit.
Step S902: the given current is differentiated to obtain a second compensation component.
Similarly, in step S902, the given current may be processed by a differentiating unit to obtain a second compensation component.
Step S903: an actual output voltage and an actual input voltage of the inverter are obtained.
It is understood that the actual output voltage and the actual input voltage of the inverter may be obtained by a sampling circuit, a voltage detection device, or other voltage data acquisition device. The actual output voltage is the voltage across the first capacitor C1, and the actual input voltage is the voltage across the second capacitor C2.
Step S904: and determining a duty cycle compensation value according to the first compensation component, the second compensation component and the output sampling current of the inverter.
It will be appreciated that the duty cycle compensation value is used to correct the duty cycle of the drive signal of the inverter 10 so that the duty cycle of the drive signal is adjusted to a suitable value to control the actual output current of the inverter 10 to approach the given current. Further, in step S904, parameters such as the first compensation component, the second compensation component, and the output sampling current of the inverter are all related to the given current, so by setting appropriate parameters, the duty cycle compensation value can be obtained by calculating the first compensation component, the second compensation component, and the actual output current.
Step S905: and calculating the target duty ratio according to the actual input voltage, the actual output voltage and the output duty ratio compensation value.
In step S905, the current duty cycle is calculated according to the actual input voltage and the actual output voltage. And then adding the current duty cycle and the output duty cycle compensation value to obtain the target duty cycle.
In this way, by executing steps S901 to S905, the target duty ratio of the driving signal of the inverter 10 can be calculated, so that the error generated by the repeated control of the inverter due to the phase slip caused by the unstable period of the actual output current is reduced in the process of driving the actual output current of the inverter 10 to approach the given current.
In some embodiments, step S904 further comprises:
and the sum of the first compensation component and the second compensation component is subjected to difference with the output sampling current of the inverter to obtain an output voltage reference value.
It is understood that in other embodiments, the calculation parameter may be added in step S904 according to the actual circuit condition or the inverter parameter, etc., so as to further accurately calculate the target duty cycle. The present application is not limited to the specific process of calculating the target duty ratio in step S904.
With continued reference to fig. 10, fig. 10 is a specific control block diagram illustrating a control method for implementing an inverter according to an embodiment of the present application by a repetitive control algorithm. Among them, the control method of the inverter may be commonly performed by using the repetitive control unit 110, the differentiating unit 120, and the SPWM modulator 130, and a specific workflow of the control method of the inverter will be described below according to a specific control block diagram shown in fig. 10:
the actual output current obtained is first subjected to a filtering process (not shown in the figure) to obtain a given current Iref. The current deviation value Idif is obtained by subtracting the given current Iref and the output sampling current Ic. The current deviation value Idif is input to the repetitive control unit 110, and the repetitive control unit 110 performs repetitive control processing on the current deviation value Idif based on a preset repetitive control algorithm to obtain a first compensation component Icom1. Meanwhile, the second compensation component Icom2 is obtained by differentiating the given current Iref by the differentiating unit 120. And summing the first compensation component Icom1 and the second compensation component Icom2, and making a difference with the output sampling current Ic to obtain a duty cycle compensation value. The actual output voltage Vc1 of the inverter is divided by the actual input voltage Vc2 of the inverter to obtain the current duty cycle. And then adding the output duty cycle compensation value and the current duty cycle to obtain a target duty cycle. Finally, the target duty cycle is input to the SPWM modulator 130, and the SPWM modulator 130 modulates the driving signal of the target duty cycle to drive the inverter 10 to output the corresponding current.
In summary, according to the control method of the inverter provided by the application, the actual output current of the inverter 10 is subjected to zero crossing detection, so that the repeated control period is confirmed according to the zero crossing. And further performs repetitive control calculation in each repetitive control period to generate a driving signal to the inverter 10. Thus, the control method of the inverter provided by the application can reduce errors caused by phase slip due to unstable actual output current period.
It will be appreciated that the present application is not limited to a specific control block diagram implementing the control method of the inverter provided by the present application. For example, referring to fig. 11, fig. 11 is a control block diagram of a control method of an inverter according to another embodiment of the application. Among these, in this control block diagram, the repetitive control calculation may be performed by employing the repetitive control unit 110, the differentiating unit 120, the SPWM modulator 130 together, and a specific workflow of the control method of the inverter will be described below according to a specific control block diagram shown in fig. 11:
the actual output current obtained is first subjected to a filtering process (not shown in the figure) to obtain a given current Iref. The current deviation value Idif is obtained by subtracting the given current Iref and the actual output sampling current Ic. The current deviation value Idif is input to the repetitive control unit 110, and the repetitive control unit 110 performs repetitive control processing on the current deviation value Idif based on a preset repetitive control algorithm to obtain a first compensation component Icom1. Meanwhile, the second compensation component Icom2 is obtained by differentiating the given current Iref by the differentiating unit 120. And summing the first compensation component Icom1 and the second compensation component Icom2 with the actual output voltage Vc1 of the inverter, and then making a difference with the output sampling current Ic of the inverter to obtain a duty cycle compensation value. Finally, the SPWM modulator 130 modulates a driving signal with a target duty ratio according to the duty ratio compensation value and the actual input voltage Vc2 of the inverter, so as to drive the inverter 10 to output a corresponding current.
In other embodiments provided by the present application, if the output voltage of the inverter is corrected by the repetitive control, the output voltage of the inverter is selected as various indicators, such as a waveform of the output voltage, a given voltage obtained by performing SOGI filtering on the output voltage twice, and the like. If the output current of the inverter is corrected by the repetitive control, the output current of the inverter is selected as various indexes such as a waveform of the output current of the inverter, a given current obtained by performing SOGI filtering on the output waveform of the inverter twice, and the like. In a specific implementation process, the selected index and the output parameter are not limited.
With continued reference to fig. 12, the present application further provides an inverter 10. The inverter 10 includes an inverter circuit 140 and a controller 150. The input end of the inverter circuit 140 is used for receiving direct current, and the output end of the inverter circuit 140 is used for outputting alternating current; the controller 150 is configured to execute the control method of the inverter as described in any one of the above.
It is understood that the inverter 10 may be integrated into an energy storage device, a self-moving robot, a refrigerator, an air conditioner, or the like. Inverter 10 may also be implemented as a stand-alone electronic device. The present application is not limited to the specific form of inverter 10.
With continued reference to fig. 13, the present application further provides a photovoltaic system 200 including the photovoltaic module 40 and the inverter 10 described above. The output end of the photovoltaic module 40 is electrically connected to the input end of the inverter 10, and the inverter 10 is configured to convert the dc power output by the photovoltaic module 40 into ac power and output the ac power.
With continued reference to fig. 14, the present application further provides an energy storage device 300, including a battery module 310 and the inverter 10 described above. The output terminal of the battery module 310 is electrically connected to the input terminal of the inverter 10. The inverter 10 is configured to convert dc power output from the battery module 310 into ac power and output the ac power.
The embodiment of the application also provides a control device which is applied to the inverter 10. Fig. 15 schematically shows a block diagram of a control apparatus 400 according to an embodiment of the present application. As shown in fig. 15, the control device 400 includes:
the obtaining module 410 is configured to obtain an actual output current of the inverter.
The filtering module 420 is configured to perform filtering processing on the actual output current to obtain a given current.
The detection module 430 is configured to perform zero crossing detection on a given current, and determine a repetition control period according to the zero crossing of the given current.
A calculation module 440, configured to perform repeated control calculation according to the given current and the output sampling current of the inverter in each repeated control period, so as to generate a driving signal to the inverter; the driving signal is used for controlling the on-off of a switching tube in the inverter.
Specific details of the control method for implementing the inverter by the control device 400 provided in the embodiment of the present application have been described in detail in the embodiment of the control method for the corresponding inverter, and are not described herein again.
The present application also provides a computer-readable medium on which a computer program is stored which, when executed by a processor, implements the control method of an inverter as in the above technical solutions. The computer readable medium may take the form of a portable compact disc read only memory (CD-ROM) and include program code that can be run on a terminal device, such as a personal computer. However, the program product of the present application is not limited thereto, and in this document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
The program product described above may take the form of any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
The computer readable signal medium may include a data signal propagated in baseband or as part of a carrier wave with readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A readable signal medium may also be any readable medium that is not a readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., connected via the Internet using an Internet service provider).
Furthermore, the above-described drawings are only schematic illustrations of processes included in the method according to the exemplary embodiment of the present application, and are not intended to be limiting. It will be readily appreciated that the processes shown in the above figures do not indicate or limit the temporal order of these processes. In addition, it is also readily understood that these processes may be performed synchronously or asynchronously, for example, among a plurality of modules.
The present application is not limited to the above embodiments, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the present application, and these modifications and substitutions are intended to be included in the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (10)

1. A control method of an inverter for converting an input direct current to output an alternating current, the control method comprising:
acquiring the actual output current of the inverter;
filtering the actual output current to obtain a given current;
detecting zero crossing points of the given current, and determining a repeated control period according to the zero crossing points of the given current;
and in each repeated control period, performing repeated control calculation according to the given current and the output sampling current of the inverter to generate a driving signal to the inverter, wherein the driving signal is used for controlling the on-off of a switching tube in the inverter.
2. The method of claim 1, wherein said determining a repetition control period from zero crossings of said given current comprises:
sequentially acquiring a first zero crossing point, a second zero crossing point and a third zero crossing point of the given current;
and when the current direction at the first zero crossing point is opposite to the current direction at the second zero crossing point, and the current direction at the second zero crossing point is opposite to the current direction at the third zero crossing point, determining the first zero crossing point as the starting point of the repeated control period, and the third zero crossing point as the end point of the repeated control period.
3. The method of claim 1, wherein the filtering the actual output current comprises:
SOGI filtering is carried out on the actual output current to obtain a given reference current;
the SOGI filtering is performed on the given reference current to obtain the given current.
4. The method of claim 1, wherein the performing a repetitive control calculation based on the given current and an output sampling current of the inverter to generate a drive signal to the inverter comprises:
generating a corresponding current deviation value according to the given current and the output sampling current of the inverter;
calculating a target duty cycle according to the current deviation value and the given current;
and generating the driving signal according to the target duty ratio.
5. The method of claim 4, wherein said calculating a target duty cycle from said current bias value and said given current comprises:
performing repeated control processing on the current deviation value to obtain a first compensation component;
differentiating the given current to obtain a second compensation component;
acquiring the actual output voltage and the actual input voltage of the inverter;
determining an output duty cycle compensation value according to the first compensation component, the second compensation component and the output sampling current of the inverter;
and calculating a target duty ratio according to the actual input voltage, the actual output voltage and the output duty ratio compensation value.
6. The method of claim 5, wherein the determining an output duty cycle compensation value from the first compensation component, the second compensation component, and an output sampling current of the inverter comprises:
and the sum of the first compensation component and the second compensation component is subjected to difference with the output sampling current of the inverter to obtain the output duty cycle compensation value.
7. The inverter is characterized by comprising an inverter circuit and a controller, wherein the input end of the inverter circuit is used for receiving direct current, and the output end of the inverter circuit is used for outputting alternating current; the controller is configured to execute the control method of the inverter according to any one of claims 1 to 6.
8. A photovoltaic system, comprising a photovoltaic module and the inverter of claim 7, wherein the output end of the photovoltaic module is electrically connected to the input end of the inverter, and the inverter is used for converting direct current output by the photovoltaic module into alternating current and outputting the alternating current.
9. An energy storage device, comprising a battery module and the inverter of claim 7, wherein the output end of the battery module is electrically connected to the input end of the inverter, and the inverter is used for converting direct current output by the battery module into alternating current and outputting the alternating current.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which, when executed by a processor, causes the processor to implement the control method of an inverter according to any one of claims 1 to 6.
CN202310769183.2A 2023-06-27 2023-06-27 Inverter and control method thereof, photovoltaic system, energy storage device and storage medium Pending CN116827096A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310769183.2A CN116827096A (en) 2023-06-27 2023-06-27 Inverter and control method thereof, photovoltaic system, energy storage device and storage medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310769183.2A CN116827096A (en) 2023-06-27 2023-06-27 Inverter and control method thereof, photovoltaic system, energy storage device and storage medium

Publications (1)

Publication Number Publication Date
CN116827096A true CN116827096A (en) 2023-09-29

Family

ID=88142516

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310769183.2A Pending CN116827096A (en) 2023-06-27 2023-06-27 Inverter and control method thereof, photovoltaic system, energy storage device and storage medium

Country Status (1)

Country Link
CN (1) CN116827096A (en)

Similar Documents

Publication Publication Date Title
Odavic et al. One-sample-period-ahead predictive current control for high-performance active shunt power filters
Yepes et al. Effects of discretization methods on the performance of resonant controllers
Tian et al. UDE-based sliding mode control of DC–DC power converters with uncertainties
Petric et al. A jitter amplification phenomenon in multisampled digital control of power converters
Low A DSP-based single-phase AC power source
Ray et al. Performance enhancement of shunt active power filter with the application of an adaptive controller
Xie et al. Systematic design of linear quadratic regulator for digitally controlled grid‐connected inverters
Kato et al. Stabilization of grid-connected inverter system with feed-forward control
CN112103970B (en) Method and device for suppressing inter-harmonic oscillation of grid-connected converter
Nikolić et al. Adaptive control based on LMS algorithm for grid-connected inverters
Liu et al. A novel PFC controller and selective harmonics suppression
Zou et al. Optimized harmonic detecting and repetitive control scheme for shunt active power filter in synchronous reference frame
CN103516180B (en) System and method for estimating component parameters
CN116827096A (en) Inverter and control method thereof, photovoltaic system, energy storage device and storage medium
CN116191425A (en) Distributed power supply harmonic compensation control method and related equipment
CN106300355B (en) A kind of resonance control method that Active Power Filter-APF calculation amount simplifies
Kissaoui et al. Output‐feedback nonlinear adaptive control of single‐phase half‐bridge ups systems
Jiao et al. Gain scheduling control strategy for a single-phase grid-connected inverter
Jasiński et al. Fuzzy logic in decision support system as a simple Human/Internet of Things interface for shunt active power filter
Li et al. Improvement of model predictive control for single‐phase inverters by using sinusoidal signal observers
Pirooz et al. Predictive voltage control of three-phase voltage source inverters to supply nonlinear and unbalanced loads
Takami et al. General-purpose computation method of a power converter for frequency characteristics: application to stability analysis of a grid inverter
Hu et al. Discrete‐time modelling and stability analysis of wireless power transfer system
JP4946642B2 (en) Harmonic current compensator
Fu et al. Single-phase PWM rectifier based on ADRC and PR control

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination