WO2013026220A1

WO2013026220A1 - Inverter system control method and device, and inverter system

Info

Publication number: WO2013026220A1
Application number: PCT/CN2011/079617
Authority: WO
Inventors: 迟屹楠
Original assignee: 深圳市英威腾电气股份有限公司
Priority date: 2011-08-19
Filing date: 2011-09-14
Publication date: 2013-02-28
Also published as: CN102291025A

Abstract

An inverter system control method and device, and an inverter system. The control method includes: detecting parameters of a transformer primary side (101), calculating an equivalent impedance voltage drop of the transformer according to the detected parameters (102), taking the equivalent impedance voltage drop, or the equivalent impedance voltage drop which has undergone at least one processing, as the amount of voltage compensation of the inverter system, and adding same to an output end of the inverter (103), thus realizing control to the inverter system.

Description

Inverter system control method, device and inverter system

This application is required to be submitted to the Chinese Patent Office on August 19, 2011, and the application number is 201110239169.9. The invention titled "Control Method, Device and Inverter System of Inverter System" has priority in Chinese patent application. The citations are incorporated herein by reference.

Technical field

The present invention relates to the field of electronic power technologies, and in particular, to a method, an apparatus, and an inverter system for controlling an inverter system.

Background technique

The inverter is also called the power regulator. According to the use of the inverter in the photovoltaic system, it can be divided into off-grid and grid-connected inverters. The off-grid inverter can be applied to villages or mountains including remote areas. Power supply systems, solar household power systems, communication signal power supplies, solar street lights, and other photovoltaic power generation systems with batteries, and inverters in specific applications are referred to as inverter systems.

In some existing inverter systems, in order to improve efficiency, no isolation transformer is connected between the output of the inverter and the load; in other inverter systems, in order to prevent leakage current, electrical isolation is achieved. An isolation transformer is connected between the output of the grid inverter and the load. In order to make the output voltage in the inverter system relatively stable, it is necessary to control the voltage and current of the inverter system. Specifically, the control of the inverter system connected to the transformer can be as follows:

It is possible to detect and control the voltage and current of the primary and secondary sides of the transformer, so that the detection and maintenance costs are relatively high, especially in the case of multiple taps on the secondary side of the transformer, it is difficult to select the sample points and the wiring is not flexible enough.

It is also possible to detect and control only the voltage and current of the primary side of the transformer (ie, the output of the inverter), but since the original and secondary windings of the transformer have resistance and leakage inductance, the load change of the transformer will cause the primary side. The impedance drop of the secondary side changes, so that the secondary voltage of the transformer decreases with the increase of the load, which causes problems such as severely cutting the output voltage of the inverter system and sharply increasing the harmonics, thus affecting the problem. The stability of the inverter system output.

Summary of the invention

The embodiment of the invention provides a control method, a device and an inverter system of the inverter system, so that the voltage of the secondary side of the transformer does not decrease with the increase of the load, thereby improving the stability of the output of the inverter system.

Embodiments of the present invention provide a method for controlling an inverter system, including: Detecting a parameter of the primary side of the transformer, and calculating a voltage drop of the equivalent impedance of the transformer according to the detected parameter, the transformer being connected between the output end of the inverter and the load in the inverter system;

The voltage drop of the equivalent impedance, or the voltage drop of the equivalent impedance after at least one treatment, is used as the voltage compensation amount of the inverter system, and is superimposed on the output end of the inverter.

Embodiments of the present invention provide a control device for an inverter system,

a detecting module, configured to detect a parameter of a primary side of the transformer, wherein the transformer is connected between the output end of the inverter and the load in the inverter system;

a calculating module, configured to calculate a voltage drop of the equivalent impedance of the transformer according to the parameter detected by the detecting module;

a superposition module, configured to use a voltage drop of an equivalent impedance calculated by the calculation module, or a voltage drop of an equivalent impedance after at least one processing as a voltage compensation amount of the inverter system, and superimposed on the inverter The output of the device.

An embodiment of the present invention provides an inverter system, including: an inverter, a transformer, a detection control circuit system, and a load;

The transformer is connected between the output end of the inverter and the load, and the detection control circuit system is connected to the primary side of the transformer; the detection control circuit system comprises:

In the embodiment of the present invention, only the parameters of the primary side of the transformer are detected, and the voltage drop of the equivalent impedance of the transformer is calculated according to the detected parameters, and the calculated equivalent impedance voltage drop or the equivalent of at least one process is obtained. The voltage drop of the impedance is used as the voltage compensation amount of the inverter system and is superimposed on the output of the inverter. Thus, if a transformer is connected to the inverter system, the control of the system takes into account the voltage drop generated by the impedance of the transformer itself, and superimposes at the output of the inverter, reducing the original secondary winding of the transformer. The influence of resistance and leakage inductance on the secondary voltage of the transformer in the group makes the secondary voltage of the transformer not decrease with the increase of the load, which improves the stability of the output of the inverter system. Moreover, in the control method of the embodiment of the present invention, it is not necessary to perform detection control on the secondary side of the transformer, thereby simplifying the hardware structure of detection and maintenance.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a schematic structural diagram of an inverter system according to an embodiment of the present invention;

2 is a flowchart of a control method of an inverter system according to an embodiment of the present invention;

3 is a flow chart of a method for calculating a voltage drop of an equivalent impedance of a transformer according to an embodiment of the present invention; FIG. 4 is a schematic structural diagram of a control device for an inverter system according to an embodiment of the present invention; FIG. 6 is a schematic structural diagram of a control device of another inverter system according to an embodiment of the present invention. FIG.

detailed description

BRIEF DESCRIPTION OF THE DRAWINGS The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of the present invention.

Embodiments of the present invention provide a control method for an inverter system, which is applicable to an inverter system as shown in FIG. 1 , the inverter system includes a photovoltaic panel, an inverter, a transformer, and a detection control circuit system. And the load, wherein the photovoltaic panel is directly connected to the inverter, and the transformer is connected between the output end of the inverter and the load; and the detection control circuit is connected with the output end of the inverter, which may also be said to be connected to the original of the transformer side.

Here, the primary side of the transformer is connected to the output of the inverter, the secondary side is connected to the load, and the secondary side can have a combination of multiple taps, which can support various internationally popular 220V, 230V, 240V, 110V, 115V, 120V and other voltages. system.

The control method of the embodiment of the present invention is mainly for the control of the application system of the off-grid inverter, where the off-grid inverter refers to an inverter that is not connected to the power grid and can be independently powered, such as an uninterruptible power supply. (Uninterruptible Power System, UPS), Figure 1 shows the power supply to the inverter through the battery. The inverter mainly converts the DC power source into an AC power source, and the detection control circuit system can control the inverter system by the following method. The flow chart is shown in FIG. 2, including:

Step 101: detecting a parameter of a primary side of the transformer;

Step 102: Calculate a voltage drop of the equivalent impedance of the transformer according to the detected parameter;

It can be understood that the detection of the parameters of the primary side of the transformer by the detection control circuit system is mainly for the parameter detection of the output end of the inverter, such as current, and the detected parameters are related to the method for calculating the voltage drop of the equivalent impedance of the transformer. Among them, the voltage drop of the equivalent impedance of the transformer is the voltage drop caused by the impedance of the transformer itself, and there are various calculation methods.

For example, an equivalent circuit of a transformer may include an equivalent inductance and an equivalent resistance, wherein a relationship between a voltage u across the equivalent inductance and a self-induced electromotive force is u=-sL, and a self-induced electromotive force sL=-Ldi/dt Therefore, u=Ldi/dt, and the voltage across the equivalent resistance is RI. It can be seen that the voltage drop generated by the transformer's own impedance is the voltage drop of the equivalent impedance of the transformer U=L*(di/dt) +RI, where L For the inductance of the equivalent inductance, R is the impedance of the equivalent resistance, I is the current flowing through the inverter, and di/dt is the rate of change of the current flowing through the inverter. It can be seen that if the influence of temperature and other factors on L and R is neglected, L and R are approximately equivalent to a constant, so that the voltage drop of the equivalent impedance of the transformer is related to the current and current change rate flowing through the transformer.

For example, if the voltage phase across the equivalent inductor of the transformer leads the phase of the current phase by π/2, and the frequency is the same, the voltage u across the equivalent inductor can also be calculated by the following formula, that is, the voltage u across the equivalent inductor is equivalent. Inductor current I* is inductive to XL, shifted to the left by 90 degrees. The inductive reactance XL=coL, where ω is the angular velocity at which the alternator operates, and L is the inductance of the equivalent inductance.

And the impedance R and the sensitivity L may be stored in the detection control circuit system, or may be calculated by using the detected parameter, specifically, = ^P . l ^f . , L = inductive reactance ΧΙ 7 ( π , where P _Q is the active power of the transformer, I. is the rated current of the transformer, f is the frequency at which the alternator operates, and the impedance of the inductive reactance is the equivalent inductance XL Z ² _ ² , where Z is the short-circuit impedance of the transformer, which indicates the magnitude of the impedance inside the transformer, that is, the impedance drop of the transformer itself when the transformer is operating at rated load. Here Z can be obtained by the following formula, ie Z=U _Q /I _Q , U _Q is the rated voltage of the transformer.

Step 103: The voltage drop of the equivalent impedance, or the voltage drop of the equivalent impedance after at least one processing, is used as the voltage compensation amount of the inverter system, and is superimposed on the output end of the inverter.

The detection control circuit system can directly use the voltage drop of the equivalent impedance calculated in step 102 as a voltage The compensation amount is superimposed on the output side of the inverter, that is, the primary side of the transformer. The voltage applied to the primary side of the transformer is the sum of the output voltage and the voltage compensation amount of the inverter itself.

The detection control circuit system may also perform at least one processing on the voltage drop of the equivalent impedance calculated in step 102, for example, performing limiting processing, and using the voltage drop of the processed equivalent impedance as the voltage of the inverter system. The amount of compensation.

It can be seen that, in the embodiment of the present invention, the detection control circuit system only needs to detect the parameters of the primary side of the transformer, and calculates the voltage drop of the equivalent impedance of the transformer according to the detected parameters, and the calculated equivalent impedance voltage drop or at least The voltage drop of a processed equivalent impedance is used as the voltage compensation amount of the inverter system and is superimposed on the output of the inverter. Thus, if a transformer is connected to the inverter system, the control of the system takes into account the voltage drop generated by the impedance of the transformer itself, and superimposes at the output of the inverter, reducing the resistance in the primary and secondary windings of the transformer. The influence of the leakage inductance on the secondary voltage of the transformer makes the secondary voltage of the transformer not decrease with the increase of the load, which improves the stability of the output of the inverter system. Moreover, in the control method of the embodiment of the present invention, it is not necessary to perform detection control on the secondary side of the transformer, thereby simplifying the hardware structure of detection and maintenance.

Referring to FIG. 3, in a specific embodiment, when performing the above step 101, the detection control circuit system can calculate the voltage drop of the equivalent impedance of the transformer by the following steps. In this embodiment, the voltage drop of the equivalent impedance is U. =L* ( di/dt ) +RI:

A1 : Obtain the inductance L of the equivalent inductance of the transformer and the impedance R of the equivalent resistance.

Here, the inductance L of the equivalent inductance and the impedance R of the equivalent resistance are approximately constant, which can be preset in the detection control circuit system, or can be calculated by the rated voltage, rated current and active power, and can also be detected and controlled. A user interface is provided in the circuit system through which the user can input L and R values.

B 1: Multiply the current change rate flowing through the transformer by the inductance L of the equivalent inductance to obtain the first component, L* (di/dt).

It can be understood that the current flowing through the transformer is the inductor current of the primary side of the transformer. In this embodiment, in order to calculate the first component, when the above step 101 is performed, the inductor current of the primary side of the transformer can be performed by an interruption. In the case of calculating the first component, the rate of change of the inductor current sampled by any two consecutive interruption periods can be multiplied by the sensed inductance L of the obtained equivalent inductance. The rate of change of the inductor current is: subtracting the inductor current from the current interrupt period to the previous interrupt period釆 The resulting inductor current is di, and the current sample time is subtracted from the previous sample time to obtain dt, then the ratio of di to dt is the rate of change of the inductor current.

C1: The current I flowing through the transformer is multiplied by the impedance R of the equivalent resistance to obtain a second component RI.

Here, the current flowing through the transformer is the inductor current of the primary side of the transformer. Specifically, it can be: multiply the instantaneous effective value of the inductor current of the transformer by 1.414 and convert it into the peak value of the inductor current, and then sine the phase of the inductor current with the phase angle of the inductor current. The value is multiplied to obtain the current I of the transformer. The instantaneous effective value of the inductor current is the current effective value of one power frequency cycle, which can be obtained by calculating the square root of the inductor current of the sample.

D1: Add the first component and the second component to obtain the voltage drop of the equivalent impedance of the transformer.

In another specific embodiment, when calculating the first component in the above step B1, the current flowing through the transformer, that is, the current I of the equivalent inductance of the transformer, may be multiplied by the inductive reactance XL of the equivalent inductance of the transformer. The phase shifted 90 degrees to the left to obtain the first component, wherein the current I is calculated in the same way as the current in step C1, and the inductive reactance of the equivalent inductance can be approximated as a constant, which is coL, or 2πί".

In other specific embodiments, in order to avoid problems such as an output voltage spike or distortion of the inverter system in the case where the inductor current of the transformer is increased, the detection control circuit system calculates the transformer equivalent by the above steps A1 to D1. After the voltage drop of the impedance, the voltage drop of the calculated equivalent impedance needs to be limited. Specifically, the first component and/or the second component of the pressure drop of the equivalent impedance calculated above may be limited.

Then, when the detection control circuit system executes the above step 103, the voltage drop of the equivalent impedance after clipping is used as the voltage compensation amount of the inverter system, and is superimposed on the output end of the inverter.

Here, the limiting of the calculated equivalent impedance voltage drop means that the voltage drop of the equivalent impedance is limited to a certain range, and the detection control circuit system can first judge the voltage drop of the equivalent impedance of the transformer, and determine the pressure. Whether the drop exceeds the preset pressure drop value, if it exceeds, the preset voltage drop value is used as the voltage compensation amount of the inverter system; if not, the calculated equivalent impedance voltage drop is used as the inverter The amount of voltage compensation for the system. Specifically, if only the first component of the voltage drop of the equivalent impedance is limited, only the first component is compared with the preset value, thereby achieving the purpose of limiting the first component; if only the equivalent The second component of the impedance voltage drop is limited, and only the second component is compared with the preset value, thereby achieving the purpose of limiting the second component.

It should be noted that the control method of the above inverter system is mainly an inverter connected to a transformer. In the control of the system, the detection control circuit system of the embodiment of the present invention is provided with a user interface in the detection control circuit system in order to be compatible with the inverter system that is not connected to the transformer, and the user can select the inverter system through the user interface. The control method, if the control mode of connecting the transformer is selected, a transformer is connected between the inverter and the load in the inverter system, and the detection control circuit system is controlled according to the control method corresponding to the embodiment of FIG. 1 above, if not selected When the control mode of the transformer is connected, there is no connection transformer between the inverter and the load in the inverter system, and it is not necessary to consider the voltage drop generated by the impedance of the transformer itself. The detection control circuit system does not calculate the voltage drop of the equivalent impedance of the transformer. The detection control circuit system can determine that the voltage compensation amount of the inverter system is 0 and is superimposed on the output end of the inverter.

The embodiment of the invention provides a control device for an inverter system, that is, a detection control circuit system in the above method embodiment, which mainly controls the off-grid inverter system, and the structure diagram is as shown in FIG. 4, including:

The detecting module 10 is configured to detect a parameter of the primary side of the transformer, and the transformer is connected between the output end of the inverter and the load in the inverter system;

The calculating module 11 is configured to calculate a voltage drop of the equivalent impedance of the transformer according to the parameter detected by the detecting module 10;

a superimposing module 12, configured to superimpose the voltage drop of the equivalent impedance calculated by the calculating module 11 or the voltage drop of the equivalent impedance after the at least one processing as the voltage compensation amount of the inverter system The output of the inverter.

In the control device of the inverter system of the embodiment of the present invention, only the detection module 10 detects the parameters of the primary side of the transformer, and the calculation module 11 calculates the voltage drop of the equivalent impedance of the transformer according to the detected parameters, which is The calculated voltage drop of the equivalent impedance or the voltage drop through the at least one processed equivalent impedance is used as the voltage compensation amount of the inverter system, superimposed on the output of the inverter. Thus, if a transformer is connected to the inverter system, the control of the system takes into account the voltage drop generated by the impedance of the transformer itself, and superimposes at the output of the inverter, reducing the resistance in the primary and secondary windings of the transformer. The influence of the leakage inductance on the secondary voltage of the transformer makes the secondary voltage of the transformer not decrease with the increase of the load, which improves the stability of the output of the inverter system. In the control device of the embodiment of the invention, the detection module 10 does not need to perform detection control on the secondary side of the transformer, thereby simplifying the hardware structure of detection and maintenance.

Referring to FIG. 5, in a specific embodiment, the calculation module 11 in the control device of the inverter system can be specifically implemented by the following structure: The obtaining module 110 is configured to acquire the inductance of the equivalent inductance of the transformer and the impedance of the equivalent resistance; the obtaining module 110 directly reads the sensed quantity and impedance stored in the control device, or receives the sensitivity of the user inputting the control device. The impedance is calculated by a certain formula. The specific formula is as described in the above method embodiment, and will not be described here.

In an actual implementation process, the acquisition module 110 can be connected to a user interface on the control device, and the user can input the sensitivity and impedance through the connected user interface.

a first component calculation module 111, configured to multiply a current change rate flowing through the transformer by a sensitivity of an equivalent inductance acquired by the acquisition module 110 to obtain a first component;

a second component calculation module 112, configured to multiply a current flowing through the transformer and an impedance of an equivalent resistance obtained by the acquisition module 110 to obtain a second component;

The component superposition module 113 is configured to add the first component calculated by the first component calculation module 111 and the second component calculated by the second component calculation module 112 to obtain a voltage drop of the equivalent impedance of the transformer.

In this embodiment, when the calculation module 11 performs the voltage drop calculation of the equivalent impedance of the transformer, the first component calculated by the first component calculation module 110 and the second component calculated by the second component calculation module 113 may be calculated by the component superposition module 113. Superimpose to calculate the pressure drop. When the first component calculation module 111 and the second component calculation module 112 calculate components, the parameters of the primary side of the transformer detected by the detection module 10 and the parameters acquired by the acquisition module 110 are calculated, and the specific calculation process is as shown in FIG. The drawings correspond to the embodiments, and are not described here.

It can be understood that the obtaining module 110 can also obtain the inductance of the equivalent inductance of the transformer, that is, the impedance of the equivalent inductor, and the first component calculating module 111 can multiply the current flowing through the transformer and the inductive reactance of the equivalent inductor. The phase shifted 90 degrees to the left gives the first component.

Referring to FIG. 6, in another specific embodiment, the control device of the inverter system may include, in addition to the structure shown in FIG. 4, a limiting module 14, a voltage drop determining module 13, and a control selection. Module 15, where:

The voltage drop determination module 13 is configured to determine whether the voltage drop of the equivalent impedance of the transformer calculated by the calculation module 11 exceeds a preset pressure drop value;

The limiting module 14 is configured to limit the voltage drop of the equivalent impedance calculated by the calculating module 11; the control selecting module 15 is configured to select a control mode for performing the inverter system, where the control mode includes connecting the transformer Control method and control method for unconnected transformer. The control selection module 15 can be a user interface, and the user can set the control mode of the inverter system through the user interface, so that the control device of the inverter system of the embodiment can be compatible with the control connection transformer and the unconnected transformer. Inverter system.

In the control device of the inverter system of the embodiment, the control mode of the inverter system can be selected by controlling the selection module 15. If the control mode of the unconnected transformer is selected, the inverter system is in the inverter and There is no connection transformer between the loads, and the impedance generated by the transformer itself is not considered. The superposition module 12 can determine that the voltage compensation amount of the inverter system is 0 and is superimposed on the output end of the inverter. In this case, except for the operation of the superimposing module 12 in the control device, other modules will not operate.

If the control mode of the connection transformer is selected, the superposition module 12 is required to increase the voltage drop of the equivalent impedance or the voltage drop of the equivalent impedance after at least one treatment as the voltage compensation amount of the inverter system, and superimpose it on the inverter. Output. In this case, each module in the control unit must be operated to control the inverter system to which the transformer is connected.

In order to avoid the occurrence of spikes or distortions in the output voltage of the inverter system, in the control device of the inverter system of the present embodiment, the pressure drop determination module 13 may first determine the voltage of the equivalent impedance of the transformer calculated by the calculation module 11. Whether the drop exceeds the preset pressure drop value, if not exceeded, the superimposing module 12 directly superimposes; if it exceeds, the limiter module 14 is required to limit the voltage drop of the equivalent impedance calculated by the calculation module 11, which is to be calculated The voltage drop of the equivalent impedance is limited to a certain range. In this case, the superimposing module 12 will use the voltage drop of the equivalent impedance after limiting by the limiting module 14 as the voltage compensation amount of the inverter system, superimposing Go to the output of the inverter.

And if the voltage drop of the equivalent impedance calculated by the calculation module 11 includes a plurality of components, the limiting module 14 may limit at least one of the voltage drops of the equivalent impedance when performing the limiting. At this time, in order to simplify the calculation of the device of the embodiment, the voltage drop determination module 13 may only judge whether one or more components exceed the preset value when the determination is made, and if it exceeds, the limiter module 14 exceeds the preset. The component of the value is clipped.

It should be noted that each module in the control device of the inverter system shown in FIG. 4 to FIG. 6 can be implemented by a separate electronic component, or can be realized by software control in the control chip, and the specific implementation thereof The form does not limit the embodiments of the present invention. An embodiment of the present invention further provides an inverter system. The schematic diagram of the structure is as shown in FIG. 1 , including: an inverter, a transformer, a detection control circuit system, and a load; Wherein the transformer is connected between the output end of the inverter and the load, and the detection control circuit system is connected to the primary side of the transformer; the structure of the detection control circuit system is similar to that shown in FIG. 4 or FIG. 5 or FIG. The structure of the control device of the inverter system. And here the inverter is mainly an off-grid inverter, that is, an inverter with a separate power supply.

A person skilled in the art may understand that all or part of the various steps of the foregoing embodiments may be performed by a program to instruct related hardware. The program may be stored in a computer readable storage medium, and the storage medium may include: Read only memory (ROM), random access memory (RAM), magnetic or optical disk, and the like.

The method, device and inverter for controlling the inverter system provided by the embodiments of the present invention are described above, and the description of the above embodiments is only for helping to understand the method and core idea of the present invention; The present invention is not limited by the scope of the present invention.

Claims

Rights request

A control method for an inverter system, comprising:

Detecting a parameter of the primary side of the transformer, and calculating a voltage drop of the equivalent impedance of the transformer according to the detected parameter, the transformer being connected between the output end of the inverter and the load in the inverter system;

2. The method according to claim 1, wherein the calculating the voltage drop of the equivalent impedance of the transformer specifically comprises:

Obtaining the inductance of the equivalent inductance of the transformer and the impedance of the equivalent resistance;

Multiplying a current change rate flowing through the transformer by a sensitivity of the equivalent inductance to obtain a first component, or multiplying a current flowing through the transformer by an inductive reactance of the equivalent inductance and then shifting to the left by 90 The phase of the degree gets the first component;

Multiplying a current flowing through the transformer with an impedance of the equivalent resistance to obtain a second component; adding the first component and the second component to obtain a voltage drop of an equivalent impedance of the transformer.

3. The method according to claim 2, wherein after calculating the voltage drop of the equivalent impedance of the transformer, the method further comprises:

Limiting the voltage drop of the equivalent impedance;

And the voltage drop of the equivalent impedance after the at least one processing is used as the voltage compensation amount of the inverter system, specifically, the voltage drop of the equivalent impedance after the limiting is used as the inverter system. The amount of voltage compensation.

4. The method of claim 3, wherein the limiting the voltage drop of the equivalent impedance comprises: a first component, and/or a second component of the voltage drop to the equivalent impedance Carry out the limit.

5. The method of claim 3, wherein the step of limiting the voltage drop of the equivalent impedance further comprises:

Determining whether the voltage drop of the equivalent impedance of the transformer exceeds a preset voltage drop value, and if so, limiting the voltage drop of the equivalent impedance.

The method according to any one of claims 1 to 5, further comprising:

Selecting the control mode of the inverter system, including the control side of the connection transformer And unconnected transformer control methods;

If the control mode of the connection transformer is selected, the voltage drop of the equivalent impedance, or the voltage drop of the equivalent impedance after at least one processing is used as the voltage compensation amount of the inverter system, superimposed on the The output of the inverter.

7. A control device for an inverter system, characterized in that

The device of claim 7, wherein the calculation module comprises: an acquisition module, configured to acquire an inductance of an equivalent inductance of the transformer and an impedance of an equivalent resistance; Multiplying a current change rate flowing through the transformer with an inductance of an equivalent inductance obtained by the acquisition module to obtain a first component, or a current flowing through the transformer and an inductive reactance of the equivalent inductance Multiplying the left phase by 90 degrees to obtain the first component;

a second component calculation module, configured to multiply a current flowing through the transformer and an impedance of an equivalent resistance obtained by the acquisition module to obtain a second component;

And a component superposition module, configured to add a first component calculated by the first component calculation module and a second component calculated by the second component calculation module to obtain a voltage drop of the equivalent impedance of the transformer.

9. The apparatus of claim 7, further comprising: a limiting module configured to limit a voltage drop of an equivalent impedance calculated by the computing module;

The superimposing module is configured to use a voltage drop of the equivalent impedance after limiting the limiting module as a voltage compensation amount of the inverter system.

10. The device according to claim 9, further comprising:

a pressure drop determination module, configured to determine whether a voltage drop of the equivalent impedance of the transformer calculated by the calculation module exceeds a preset pressure drop value;

The limiting module is configured to: when the voltage drop determining module determines the transformer calculated by the calculating module The voltage drop of the equivalent impedance exceeds a preset voltage drop value, and the voltage drop of the equivalent impedance is limited.

The device according to any one of claims 7 to 10, further comprising: a control selection module, configured to select a control mode for performing the inverter system, wherein the control mode includes a control mode of connecting the transformer and Control method in which the transformer is not connected;

The superimposing module is configured to: when the control selection module selects a control mode of the connection transformer, use a voltage drop of the equivalent impedance, or a pressure drop of an equivalent impedance after at least one processing as the inverse The voltage compensation amount of the transformer system is superimposed on the output of the inverter.

12. An inverter system, comprising: an inverter, a transformer, a detection control circuit system, and a load;

The transformer is connected between an output end of the inverter and a load, and the detection control circuit system is connected to a primary side of the transformer; the detection control circuit system is according to any one of claims 7 to 12 Control device for the inverter system.