阅读说明：本技术 一种逆变器的参数在线辨识方法 (Parameter online identification method for inverter ) 是由 施建强 李双 徐梦溪 田峰敏 于 2021-06-29 设计创作，主要内容包括：本发明公开了一种逆变器的参数在线辨识方法,包括：获取逆变器闭环调制波的基波分量；将获取到的基波分量作为逆变器开环调制信号波,将逆变器切换至开环调制,并运行半个周期；采集并预处理逆变器三相电压电流数据,得到电压电流的基波d、q轴分量；将得到的电压电流的基波d、q轴分量输入预先获得的求解表达式,计算得到逆变器的电感、电容参数。本发明不需要获取电感、电容参数的初值就能够在线辨识滤波电感、电容参数,且在逆变器不同负载强度下以及电感、电容参数偏移时均能够保证辨识精度。(The invention discloses an inverter parameter online identification method, which comprises the following steps: acquiring a fundamental component of a closed-loop modulation wave of an inverter; taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle; collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current; and inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression, and calculating to obtain the inductance and capacitance parameters of the inverter. The method can identify the filter inductance and capacitance parameters on line without acquiring initial values of the inductance and capacitance parameters, and can ensure the identification precision under different load strengths of the inverter and during the deviation of the inductance and capacitance parameters.)

1. An inverter parameter online identification method is characterized by comprising the following steps:

acquiring a fundamental component of a closed-loop modulation wave of an inverter;

taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle;

collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

and inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression, and calculating to obtain the inductance and capacitance parameters of the inverter.

2. The method for online parameter identification of an inverter according to claim 1, wherein the obtaining a fundamental component of a closed-loop modulation wave of the inverter comprises: and performing one-cycle integration on the inverter closed-loop modulation wave component, and extracting to obtain a fundamental component of the inverter closed-loop modulation wave.

3. The method for online parameter identification of an inverter according to claim 1, wherein the half cycle has a duration of 0.01 s.

4. The method for online parameter identification of inverter according to claim 1, wherein the inverter three-phase voltage current data are inverter inductive current i and capacitor voltage u₀Output current i₀The three-phase data of (1).

5. The method for identifying the parameters of the inverter on line according to claim 4, wherein the step of collecting and preprocessing the three-phase voltage current data of the inverter to obtain the d and q axis components of the fundamental wave of the voltage current comprises:

collecting inductance current i and capacitance voltage u of inverter₀Output current i₀The three-phase data of (1);

using park transformation to convert the inductive current i and the capacitor voltage u₀Output current i₀Converting the open-loop modulation signal wave from a three-phase stationary coordinate system to a two-phase synchronous rotating coordinate system to obtain d and q axis components of the voltage and the current;

and performing periodic integration on the d and q axis components of the voltage and the current to obtain the d and q axis components of the fundamental wave of the voltage and the current.

6. The method for identifying parameters of an inverter as claimed in claim 1, wherein the pre-obtained solving expression is obtained by the following steps:

according to the inverter circuit structure, establishing a voltage-current equation under a three-phase static coordinate system, wherein the equation is shown as the following formula:

in the formula (1), i_a、i_b、i_cRepresenting the three-phase current of the filter inductor; i.e. i_oa、i_ob、i_ocRepresents the inverter output current; u. of_a、u_b、u_cRepresenting the midpoint voltage of a bridge arm of the inverter; u. of_oa、u_ob、u_ocRepresenting an inverter output voltage; l represents a filter inductance; r represents the parasitic resistance of the filter inductance L; c represents a filter capacitor;

performing park transformation on the formula (1) to obtain a voltage-current equation under a two-phase synchronous rotating coordinate system, which is shown as the following formula:

in the formulae (2) and (3), u_d1、u_q1Fundamental wave d-axis and q-axis components of a bridge arm midpoint voltage u are represented; i.e. i_d1、i_q1Representing fundamental wave d-axis and q-axis components of an inverter inductance current i; u. of_od1、u_oq1Representing inverter capacitor voltage u₀Fundamental d-axis and q-axis components of (1); i.e. i_od1、i_oq1Representing the inverter output current i₀The fundamental d-axis and q-axis components of (a), omega represents the fundamental angular frequency;

obtaining a solving expression of the filter inductance-capacitance parameter of the inverter according to the formula (2) and the formula (3), wherein the solving expression is shown as the following formula:

。

7. the method for identifying the parameters of the inverter on line according to claim 6, wherein the bridge arm midpoint voltage u is equal to an open-loop modulation signal wave of the inverter after the inverter is switched to open-loop modulation and operated for a half period.

8. The method for online parameter identification of the inverter according to claim 1, further comprising restoring the inverter to the closed-loop modulation mode after calculating the parameters of the inductance and the capacitance of the inverter.

9. An on-line parameter identification device for an inverter, comprising:

an acquisition module: the method comprises the steps of obtaining a fundamental component of a closed-loop modulation wave of an inverter;

an inverter switching module: the inverter is used for switching the inverter to open-loop modulation and operating for a half cycle by taking the obtained fundamental component as an open-loop modulation signal wave of the inverter;

a first calculation module: the system is used for collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

a second calculation module: and the method is used for inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression and calculating to obtain the inductance and capacitance parameters of the inverter.

Technical Field

The invention relates to an inverter parameter online identification method, and belongs to the technical field of inverter parameter identification.

Background

Inverters are widely used as electric energy conversion devices for connecting a dc voltage source and an ac load (or a grid), and include, for example, grid-connected inverters, Uninterruptible Power Supplies (UPS), dynamic voltage restorers, and the like.

In order to realize accurate tracking of the command value and simultaneously quickly respond to the change of the load, the current main control methods of the inverter include: voltage single-loop control, voltage outer-loop current inner-loop double-closed-loop control, optimal output voltage control, sliding mode variable structure control, prediction control and the like. The voltage and current double closed-loop control has the advantages of simple structure, clear physical significance, complete theoretical basis and the like.

When the double-loop controller is a PI controller, because a steady-state error exists when the PI controller tracks an alternating current command, a Park transformation is needed to be used for transforming voltage and current from a three-phase stationary coordinate system to a synchronous rotating coordinate system for control, and the transformed d-axis voltage and current components and the transformed q-axis voltage and current components are coupled and are generally decoupled in a feedforward mode. However, parameter errors of the filter capacitance inductance can affect the decoupling effect.

In the prior art, the following improvements are made to the conventional dual closed-loop control strategy: and a disturbance observer is introduced, and the coupling term and load current change are regarded as disturbance, so that the sensitivity index of the system is improved, and the anti-interference capability of the system is improved. However, the PI parameter design of the controller has a large influence on the closed-loop performance of the system, and when errors exist in the capacitance, the inductance and the resistance, the transfer function model of the system is inaccurate, so that the design effect of the PI parameter is influenced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides an inverter parameter online identification method, which can identify filter inductance and capacitance parameters online without acquiring initial values of the inductance and capacitance parameters, and can ensure identification accuracy under different load strengths of an inverter and during the offset of the inductance and capacitance parameters. In order to achieve the purpose, the invention is realized by adopting the following technical scheme:

in a first aspect, the present invention provides an online parameter identification method for an inverter, including:

acquiring a fundamental component of a closed-loop modulation wave of an inverter;

taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle;

collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

and inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression, and calculating to obtain the inductance and capacitance parameters of the inverter.

With reference to the first aspect, further, the acquiring a fundamental component of the inverter closed-loop modulation wave includes: and performing one-cycle integration on the inverter closed-loop modulation wave component, and extracting to obtain a fundamental component of the inverter closed-loop modulation wave.

With reference to the first aspect, further, the duration of the half period is 0.01 s.

With reference to the first aspect, the inverter three-phase voltage current data include an inverter inductor current i and a capacitor voltage u₀Output current i₀The three-phase data of (1).

With reference to the first aspect, further, the acquiring and preprocessing three-phase voltage and current data to obtain d and q axis components of fundamental waves of the voltage and current includes:

collecting inductance current i and capacitance voltage u of inverter₀Output current i₀The three-phase data of (1);

using park transformation to convert the inductive current i and the capacitor voltage u₀Output current i₀Converting the open-loop modulation signal wave from a three-phase stationary coordinate system to a two-phase synchronous rotating coordinate system to obtain d and q axis components of the voltage and the current;

and performing periodic integration on the d and q axis components of the voltage and the current to obtain the d and q axis components of the fundamental wave of the voltage and the current.

With reference to the first aspect, further, the pre-obtained solving expression is obtained by:

according to the inverter circuit structure, establishing a voltage-current equation under a three-phase static coordinate system, wherein the equation is shown as the following formula:

in the formula (1), i_a、i_b、i_cRepresenting the three-phase current of the filter inductor; i.e. i_oa、i_ob、i_ocRepresents the inverter output current; u. of_a、u_b、u_cRepresenting the midpoint voltage of a bridge arm of the inverter; u. of_oa、u_ob、u_ocRepresenting an inverter output voltage; l represents a filter inductance; r represents the parasitic resistance of the filter inductance L; c represents a filter capacitor;

performing park transformation on the formula (1) to obtain a voltage-current equation under a two-phase synchronous rotating coordinate system, which is shown as the following formula:

in the formulae (2) and (3), u_d1、u_q1Fundamental wave d-axis and q-axis components of a bridge arm midpoint voltage u are represented; i.e. i_d1、i_q1Representing fundamental wave d-axis and q-axis components of an inverter inductance current i; u. of_od1、u_oq1Representing inverter capacitor voltage u₀Fundamental d-axis and q-axis components of (1); i.e. i_od1、i_oq1Representing the inverter output current i₀The fundamental d-axis and q-axis components of (a), omega represents the fundamental angular frequency;

obtaining a solving expression of the filter inductance-capacitance parameter of the inverter according to the formula (2) and the formula (3), wherein the solving expression is shown as the following formula:

with reference to the first aspect, further, the bridge arm midpoint voltage u is equal to an inverter open-loop modulation signal wave after switching the inverter to open-loop modulation and operating for half a cycle.

With reference to the first aspect, the method further includes restoring the inverter to the closed-loop modulation mode after the inductance and capacitance parameters of the inverter are calculated.

In a second aspect, the present invention provides an apparatus for online identifying parameters of an inverter, including:

an acquisition module: the method comprises the steps of obtaining a fundamental component of a closed-loop modulation wave of an inverter;

an inverter switching module: the inverter is used for switching the inverter to open-loop modulation and operating for a half cycle by taking the obtained fundamental component as an open-loop modulation signal wave of the inverter;

a first calculation module: the system is used for collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

a second calculation module: and the method is used for inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression and calculating to obtain the inductance and capacitance parameters of the inverter.

Compared with the prior art, the method for identifying the parameters of the inverter on line provided by the embodiment of the invention has the beneficial effects that:

the method comprises the steps of obtaining a fundamental component of a closed-loop modulation wave of an inverter; taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle; collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current; according to the invention, fundamental wave d and q axis components of voltage and current are input into a pre-obtained solving expression, inductance and capacitance parameters of the inverter are obtained through calculation, and filter inductance and capacitance parameters can be identified on line without acquiring initial values of the inductance and capacitance parameters; the open-loop modulation signal wave is used for replacing and omitting a bridge arm midpoint voltage sensor, so that the hardware cost is saved; the method can ensure the identification precision under different load strengths of the inverter and during the deviation of inductance and capacitance parameters, and cannot influence the operation of a system; the method has great significance for improving the closed-loop performance of the system and improving the robustness.

Drawings

FIG. 1 is a flow chart of a method for online identification of parameters of an inverter according to the present invention;

FIG. 2 is a topological structure diagram of an inverter circuit in the method for identifying parameters of an inverter on line according to the present invention;

fig. 3 is a timing diagram of an online parameter identification method for an inverter according to the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The first embodiment is as follows:

as shown in fig. 1, an embodiment of the present invention provides an online parameter identification method for an inverter, including:

acquiring a fundamental component of a closed-loop modulation wave of an inverter;

taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle;

collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

and inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression, and calculating to obtain the inductance and capacitance parameters of the inverter.

As shown in fig. 3, the timing diagram includes the following steps:

step 1: and establishing a voltage and current equation under a three-phase static coordinate system according to the circuit structure of the inverter, performing park transformation to obtain a voltage and current equation under a two-phase synchronous rotating coordinate system, and solving an expression of filter inductance and capacitance parameters of the inverter.

Step 1.1: according to the topology structure diagram of the inverter circuit shown in fig. 2, a voltage-current equation under a three-phase static coordinate system is established as shown in the following formula:

in the formula (1), i_a、i_b、i_cRepresenting the three-phase current of the filter inductor; i.e. i_oa、i_ob、i_ocRepresents the inverter output current; u. of_a、u_b、u_cRepresenting the midpoint voltage of a bridge arm of the inverter; u. of_oa、u_ob、u_ocRepresenting an inverter output voltage; l represents a filter inductance; r represents the parasitic resistance of the filter inductance L; and C represents a filter capacitance.

Step 1.2: performing park transformation on the formula (1) to obtain a voltage-current equation under a two-phase synchronous rotating coordinate system, which is shown as the following formula:

in the formulae (2) and (3), u_d1、u_q1Fundamental wave d-axis and q-axis components of a bridge arm midpoint voltage u are represented; i.e. i_d1、i_q1Representing fundamental wave d-axis and q-axis components of an inverter inductance current i; u. of_od1、u_oq1Representing inverter capacitor voltage u₀Fundamental d-axis and q-axis components of (1); i.e. i_od1、i_oq1Representing the inverter output current i₀And ω represents the fundamental angular frequency.

Step 1.3: obtaining a solving expression of the filter inductance-capacitance parameter of the inverter according to the formula (2) and the formula (3), wherein the solving expression is shown as the following formula:

step 2: and acquiring a fundamental component of the inverter closed-loop modulation wave.

Specifically, according to the periodicity of the trigonometric function, the inverter closed-loop modulation wave component is integrated for one period, and the fundamental wave component of the inverter closed-loop modulation wave is extracted and obtained.

And step 3: and taking the obtained fundamental component as an open-loop modulation signal wave of the inverter, switching the inverter to open-loop modulation, and operating for a half cycle.

Specifically, the duration of the half cycle is 0.01 s. The bridge arm midpoint voltage u in step 1.2 and step 1.3 is equal to the inverter open-loop modulation signal wave after switching the inverter to open-loop modulation and operating for half a cycle.

And 4, step 4: the method comprises the steps of collecting and preprocessing three-phase voltage and current data of an inverter to obtain fundamental wave d and q axis components of the voltage and current.

Step 4.1: collecting inductance current i and capacitance voltage u of inverter₀Output current i₀The three-phase data of (1).

Step 4.2: using park transformation to convert the inductive current i and the capacitor voltage u₀Output current i₀And converting the open-loop modulation signal wave from the three-phase stationary coordinate system to the two-phase synchronous rotating coordinate system to obtain d and q axis components of the voltage and the current.

Step 4.3: and performing periodic integration on the d and q axis components of the voltage and the current to obtain the d and q axis components of the fundamental wave of the voltage and the current.

And 5: and (3) inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into the solving expression obtained in step (1) in advance, and calculating to obtain the inductance and capacitance parameters of the inverter.

Specifically, the solved expressions obtained in advance are expressions (4), (5), and (6).

Step 6: and after the inductance and capacitance parameters of the inverter are obtained through calculation, the inverter is restored to a closed-loop modulation mode.

Example two:

the embodiment of the invention provides an on-line identification device for parameters of an inverter, which comprises:

an acquisition module: the method comprises the steps of obtaining a fundamental component of a closed-loop modulation wave of an inverter;

an inverter switching module: the inverter is used for switching the inverter to open-loop modulation and operating for a half cycle by taking the obtained fundamental component as an open-loop modulation signal wave of the inverter;

a first calculation module: the system is used for collecting and preprocessing three-phase voltage and current data of the inverter to obtain fundamental wave d and q axis components of the voltage and current;

a second calculation module: and the method is used for inputting the obtained d and q axis components of the fundamental wave of the voltage and the current into a pre-obtained solving expression and calculating to obtain the inductance and capacitance parameters of the inverter.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.