Method for acquiring two-port network parameters of DC / DC (Direct Current / Direct Current) converter without influence of source and load

Abstract

The invention provides a method for acquiring two-port network parameters of a DC / DC converter without influence of a source and a load. The method comprises the following steps: S1, acquiring DC voltage source output impedance and electronic load input admittance data in a concerned frequency band through a general test method; s2, acquiring nominal input admittance, nominal voltage gain, nominal output impedance and nominal reverse current gain data of the DC / DC converter in the concerned frequency band; and S3, drawing a control block diagram and carrying out further derivation by using a Meisson gain formula to obtain two-port network parameters of the converter. The method for acquiring the two-port network parameters of the DC / DC converter provided by the invention is not only suitable for various testing methods for acquiring the two-port network parameters of the DC / DC converter based on a general frequency response method, but also effectively peels off the port characteristic parameters of the source and the load, and more accurately depicts the two-port network characteristics of the converter.

Description

Technical Field

[0001] The invention belongs to the technical field of direct current converters, and in particular relates to a method for acquiring two-port network parameters of a DC / DC converter which is not affected by a source and a load. Background Art

[0002] DC / DC converters are widely used in new energy power systems mainly composed of photovoltaics and energy storage batteries, isolated space power supplies and other fields to achieve the allocation and consumption of different types of energy. Their stability and ability to resist shock disturbances are of great significance to the stable operation of various power supply systems.

[0003] For a converter operating near a steady-state operating point, a two-port network model based on small signal theory that reflects its port characteristics can be constructed through four transfer functions: voltage gain, output impedance, input admittance, and reverse current gain. This model is essential for analyzing the operating stability of a multi-DC / DC converter power supply system. However, the frequency response test of a DC / DC converter in the engineering field requires online access to the source and load (such as a DC power supply and a simulated electronic load), so that the output impedance of the source and the input impedance characteristics of the load are coupled in the measured DC / DC converter two-port network parameters. Therefore, there is room for further improvement in the accuracy of the actual measured two-port network parameters in describing the converter port characteristics. Summary of the invention

[0004] In order to solve the problem that the measured frequency response parameters are coupled with the port impedance parameters of the test equipment and the converter's own port characteristics are not accurately described, the present invention provides a method for obtaining the two-port network parameters of a DC / DC converter that removes the influence of source and load. The specific technical solution is as follows:

[0005] A method for obtaining parameters of a two-port network of a DC / DC converter with source and load effects removed, the method comprising:

[0006] S1. Obtain the output impedance Z of the DC voltage source within the frequency band of interest through a general test method S And the electronic load input admittance Y L data;

[0007] S2. Obtain the nominal input admittance Y′ of the DC / DC converter within the frequency band of interest in , nominal voltage gain G', nominal output impedance Z' o And the nominal reverse current gain H i 'data;

[0008] S3. By drawing the control block diagram and applying the Mason gain formula for further deduction, the two-port network parameters of the converter itself are obtained.

[0009] Furthermore, the output impedance Z in step S1 S And the electronic load input admittance Y L The data is obtained according to the general test method or the data provided by the equipment manufacturer;

[0010] Furthermore, the general test method in step S1 includes a commonly used frequency response method;

[0011] Furthermore, the nominal input admittance in step S2 applies a series voltage disturbance between the converter input terminal and the source output terminal. Measure the nominal input admittance in the frequency band of interest:

[0012] Furthermore, the nominal voltage gain in step S2 is obtained by applying a series voltage disturbance between the converter input terminal and the source output terminal. The nominal voltage gain in the frequency band of interest is measured as:

[0013] Furthermore, the nominal output impedance in step S2 applies a parallel current disturbance between the converter output terminal and the load input terminal. Measured nominal output impedance within the frequency band of interest:

[0014] Furthermore, the nominal reverse current gain in step S2 applies a parallel current disturbance between the converter output terminal and the load input terminal. Measured within the frequency band of interest: Nominal reverse current gain:

[0015] Furthermore, the nominal input admittance Y′ in step S2 in , the nominal voltage gain G', the nominal output impedance Z' o And the nominal reverse current gain H i 'Data, all coupled with the port impedance parameters of the test equipment;

[0016] Furthermore, the two-port network parameters of the converter itself obtained in step S3 include: input admittance Y in , voltage gain G, reverse current gain H i , output impedance Z o , the specific derivation formula is as follows:

[0017] The input admittance is: Y in =Y i ' n -G'*H i '*Y L / (1+G'*H i '*Y L *ZS )

[0018] Voltage gain is: G = G'*(1+Y L *Z' o ) / (1+G'*H i '*Y L *Z S )

[0019] The reverse current gain is: H i =H i '*(1+Y i ' n *Z S ) / (1+G'*H i '*Y L *Z S )

[0020] The output impedance is: Z o =Z' o -G'*H i '*Z S / (1+G'*H i '*Y L *Z S )

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The method for obtaining the two-port network parameters of a DC / DC converter provided by the present invention is not only applicable to various test methods for obtaining the two-port network parameters of a DC / DC converter based on a general frequency response method, but also effectively strips off the port characteristic parameters of the source and the load, and more accurately describes the two-port network characteristics of the converter itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the steps of a two-port network parameter acquisition method provided by the present invention that is not affected by the source and the load;

[0025] Figure 2 A schematic diagram of the principle of a two-port network parameter acquisition method provided by the present invention that is not affected by the source and the load;

[0026] Figure 3A control schematic diagram of obtaining the input admittance and voltage gain of a converter involved in the acquisition method provided by the present invention;

[0027] Figure 4 The present invention provides a control schematic diagram for obtaining the reverse current gain and output impedance of a converter involved in the acquisition method provided by the present invention.

[0028] Reference numerals: G, voltage gain; output impedance Z o ; Y in , input admittance; H i , reverse current gain;

[0029] Y′ in , nominal input admittance; G', nominal voltage gain; Z' o , nominal output impedance; H′ i , nominal reverse current gain.

[0030] Specific implementation methods

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] A method for obtaining parameters of a two-port network of a DC / DC converter by removing the influence of source and load, such as Figure 1 As shown, the method comprises the following steps:

[0033] S1. Obtain the output impedance Z of the DC voltage source within the frequency band of interest through a general test method S And the electronic load input admittance Y L data;

[0034] S2. Obtain the nominal input admittance Y′ of the DC / DC converter within the frequency band of interest in , nominal voltage gain G', nominal output impedance Z' o And the nominal reverse current gain H′ i data;

[0035] S3. By drawing the control block diagram and applying the Mason gain formula for further deduction, the two-port network parameters of the converter itself are obtained.

[0036] The general test method described in step S1 includes a commonly used frequency response method;

[0037] The nominal input admittance in step S2 applies a series voltage disturbance between the converter input and the source output. Measure the nominal input admittance in the frequency band of interest:

[0038] The nominal voltage gain in step S2 is the voltage gain of the converter when a series voltage disturbance is applied between the converter input and the source output. The nominal voltage gain in the frequency band of interest is measured as:

[0039] The nominal output impedance in step S2 applies a parallel current disturbance between the converter output terminal and the load input terminal. Measured nominal output impedance within the frequency band of interest:

[0040] The nominal reverse current gain in step S2 applies a parallel current disturbance between the converter output and the load input. Measured within the frequency band of interest: Nominal reverse current gain:

[0041] The nominal input admittance Y′ in step S2 in , the nominal voltage gain G', the nominal output impedance Z' o And the nominal reverse current gain H i 'Data, all coupled with the port impedance parameters of the test equipment;

[0042] The two-port network parameters of the converter obtained in step S3 include: input admittance Y in , voltage gain G, reverse current gain H i , output impedance Z o , the specific derivation formula is as follows:

[0043] The input admittance is: Y in =Y i ' n -G'*H i '*Y L / (1+G'*H i '*Y L *Z S )

[0044] Voltage gain is: G = G'*(1+Y L *Z' o ) / (1+G'*H i '*Y L *Z S )

[0045] The reverse current gain is: H i =H i '*(1+Y i ' n *Z S ) / (1+G'*H i '*Y L *Z S )

[0046] The output impedance is: Z o=Z' o -G'*H i '*Z S / (1+G'*H i '*Y L *Z S ).

[0047] like Figure 2 As shown in FIG. 1 , a schematic diagram of the principle of a two-port network parameter acquisition method provided by the present invention that is not affected by the source and the load. A DC / DC converter operating near a certain steady-state operating point can be obtained by voltage gain G, output impedance Z o 、Input admittance Y in And the reverse current gain H i These four transfer functions construct a two-port network model based on small signal theory that reflects its port characteristics. This model is crucial for analyzing and evaluating the operating stability of multi-DC / DC converter power supply systems.

[0048] However, in the common test method for obtaining the two-port network parameters of the DC / DC converter based on the frequency response method, the measured two-port network parameters of the DC / DC converter couple the output impedance of the front-end DC voltage source and the input impedance of the back-end load to varying degrees. Figure 2 As shown, specifically:

[0049] A series voltage disturbance is applied between the converter input and the source output. Measured

[0050] Input voltage With input current The ratio of the nominal input admittance

[0051] Output voltage With input voltage The ratio of the nominal voltage gain

[0052] A parallel current disturbance is applied between the converter output and the load input. Measured

[0053] Output voltage With output current The ratio of the nominal output impedance

[0054] Input Current With output current The ratio of the nominal reverse current gain

[0055] In order to illustrate how the two-port network parameters of the DC / DC converter obtained based on the universal frequency response method couple the output impedance of the front-end DC voltage source and the input impedance of the back-end load to different degrees, the present invention provides control schematic diagrams under the above two test scenarios as shown in FIG. Figure 3 and Figure 4 As shown, based on the control schematic diagram, the Mersenne gain formula can be used to derive:

[0056] Measured nominal input admittance Input admittance Y coupled to the electronic load L , not the input admittance Y of the converter itself in ;

[0057] Measured nominal voltage gain The input admittance Y of the electronic load is also coupled L , not the voltage gain G of the converter itself;

[0058] Measured nominal output impedance The output impedance Z coupled to the DC power supply S , not the output impedance Z of the converter itself o ;

[0059] Measured nominal reverse current gain The output impedance Z of the DC power supply is also coupled S , not the converter's own reverse current gain H i .

[0060] Based on this, the present invention further provides a method for calculating the parameters of a two-port network of a DC / DC converter that is not affected by the source and the load as follows, namely:

[0061] The input admittance is:

[0062] Y in =Y i ' n -G'*H i '*Y L / (1+G'*H i '*Y L *Z S )

[0063] The voltage gain is:

[0064] G=G'*(1+Y L *Z' o ) / (1+G'*H i '*Y L *Z S )

[0065] The reverse current gain is:

[0066] H i =H i '*(1+Y i ' n *Z S ) / (1+G'*H i '*Y L *Z S )

[0067] The output impedance is:

[0068] Z o =Z' o -G'*H i '*Z S / (1+G'*H i '*Y L *Z S )

[0069] It can be seen that it effectively strips off the port characteristic parameters of the source and load, and is a more accurate characterization of the two-port network characteristics of the converter itself.

[0070] Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention. The contents not described in detail in the specification of the present invention belong to the known technology of professional and technical personnel in this field.

Claims

1. A method for obtaining parameters of a two-port network of a DC / DC converter without the influence of source and load, characterized in that: The method comprises the following steps: S1. Obtain the output impedance Z of the DC voltage source within the frequency band of interest through a general test method S And the electronic load input admittance Y L data; S2. Obtain the nominal input admittance Y of the DC / DC converter within the frequency band of interest i ' n , nominal voltage gain G', nominal output impedance Z' o And the nominal reverse current gain H i 'data; S3. By drawing the control block diagram and applying the Mason gain formula for further deduction, the two-port network parameters of the converter itself are obtained.

2. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The general testing method in step S1 includes a frequency response method.

3. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The nominal input admittance in step S2 applies a series voltage disturbance between the converter input and the source output. The ratio of the converter output voltage to the input voltage is measured, that is, the nominal input admittance:

4. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The nominal voltage gain in step S2 is the voltage gain of the converter when a series voltage disturbance is applied between the converter input and the source output. Measuring the converter output voltage With input voltage The ratio of is obtained, that is, the nominal voltage gain:

5. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The nominal output impedance in step S2 applies a parallel current disturbance between the converter output terminal and the load input terminal. Measured nominal output impedance within the frequency band of interest:

6. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The nominal reverse current gain in step S2 applies a parallel current disturbance between the converter output and the load input. Measuring the converter output voltage With output current The ratio of is obtained, that is, the nominal reverse current gain:

7. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The nominal input admittance Y in step S2 i ' n , the nominal voltage gain G', the nominal output impedance Z' o And the nominal reverse current gain H i 'Data are coupled with the port impedance parameters of the test equipment.

8. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 1, characterized in that: The two-port network parameters of the converter in step S3 include: input admittance Y in , voltage gain G, reverse current gain H i , output impedance Z o .

9. The method for obtaining parameters of a two-port network of a DC / DC converter according to claim 8, characterized in that: The derivation formula of the input admittance is Y in =Y i ' n -G'*H i '*Y L / (1+G'*H i '*Y L *Z S ); The voltage gain is derived as follows: G = G'*(1+Y L *Z' o ) / (1+G'*H i '*Y L *Z S ); The derivation formula of the reverse current gain is: H i =H i '*(1+Y i ' n *Z S ) / (1+G'*H i '*Y L *Z S ); The output impedance is derived as follows: o =Z' o -G'*H i '*Z S / (1+G'*H i '*Y L *Z S ).

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