Three-phase rectifier output impedance modeling method, device and equipment considering DC side LC filtering unit and medium

Abstract

The invention discloses a three-phase rectifier output impedance modeling method and device considering a DC side LC filtering unit, equipment and a medium. The method comprises the following steps: obtaining structure parameters of each component of the three-phase rectifier; establishing a three-phase rectifier loop working model based on the structure parameters according to the Kirchhoff's law; performing Park transformation on the three-phase rectifier loop working model to determine a three-phase rectifier loop working transformation model; performing disturbance signal separation on each variable in the three-phase rectifier loop work transformation model, and determining a three-phase rectifier disturbance signal model in combination with a preset disturbance current signal; determining a three-phase rectifier disturbance signal closed-loop control model; and determining a three-phase rectifier output impedance model according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model. According to the scheme, accurate modeling of the output impedance of the three-phase rectifier containing the LC filtering unit is realized through a d-q axis Park linearization conversion method.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of three-phase rectifiers, and in particular to a method, device, equipment and medium for modeling the output impedance of a three-phase rectifier taking into account a DC side LC filter unit. Background Art

[0002] With the vigorous development of new energy generation technologies such as wind power generation and photovoltaic power generation, more and more distributed power sources are widely used in power systems, and power electronic converters such as rectifiers and inverters that can perform power conversion are also widely used in power systems. However, the negative impedance characteristics of power electronic converters may cause system oscillations and bring hidden dangers of instability to the system. Therefore, it is necessary to judge the stability of power electronic converters from the perspective of impedance characteristics.

[0003] The three-phase PWM rectifier can realize AC / DC conversion and is widely used in new energy power generation fields such as wind power generation and photovoltaic power generation. Its internal LC filter unit has a certain effect on suppressing DC side ripple and is also often used on the DC side. Taking the three-phase PWM rectifier and the DC side LC filter unit as a whole, establishing an output impedance model, and applying the impedance stability criterion to perform system stability analysis is a method to improve system stability. Therefore, impedance modeling of the three-phase PWM rectifier containing the LC filter unit is crucial. At present, the accuracy of impedance modeling of the three-phase PWM rectifier containing the LC filter unit is poor. Summary of the invention

[0004] The present invention provides a method, device, equipment and medium for modeling the output impedance of a three-phase rectifier taking into account a DC side LC filter unit, and realizes accurate modeling of the output impedance of a three-phase PWM rectifier containing an LC filter unit through a dq axis Parker linearization conversion method.

[0005] To achieve the above objectives, in a first aspect, an embodiment of the present invention provides a method for modeling output impedance of a three-phase rectifier considering a DC side LC filter unit, the method comprising:

[0006] Obtaining structural parameters of a three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitance parameters in an LC filter unit, inductance parameters in an LC filter unit, and load resistance parameters;

[0007] According to Kirchhoff's law, a three-phase rectifier circuit working model is established based on the structural parameters;

[0008] Performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model;

[0009] Separating disturbance signals of variables in the three-phase rectifier loop working transformation model, and combining preset disturbance current signals to determine a three-phase rectifier disturbance signal model;

[0010] Determine the closed-loop control model of the disturbance signal of the three-phase rectifier;

[0011] A three-phase rectifier output impedance model is determined according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model.

[0012] Optionally, the method further includes: obtaining a theoretical output impedance spectrum of the three-phase rectifier based on a frequency sweeper;

[0013] Simulating and calculating the output impedance model of the three-phase rectifier to determine a simulated output impedance spectrum of the three-phase rectifier;

[0014] The structural parameters of the components of the three-phase rectifier or the control parameters in the closed-loop control model of the disturbance signal of the three-phase rectifier are adjusted according to the simulated output impedance spectrum and the theoretical output impedance spectrum.

[0015] Optionally, according to Kirchhoff's law, a three-phase rectifier loop working model is established based on the structural parameters, including:

[0016] According to Kirchhoff's voltage law, a voltage loop working model of a three-phase rectifier is established based on the structural parameters;

[0017] According to Kirchhoff's current law, a three-phase rectifier current loop working model is established based on the structural parameters;

[0018] The output DC voltage loop working model of the rectifier bridge in the three-phase rectifier is determined according to the three-phase rectifier current loop working model; wherein the three-phase rectifier loop working model includes the three-phase rectifier voltage loop working model, the three-phase rectifier current loop working model and the output DC voltage loop working model of the rectifier bridge in the three-phase rectifier.

[0019] Optionally, performing a Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model includes:

[0020] Performing Park transformation on the three-phase rectifier voltage loop working model to determine the three-phase rectifier voltage loop working transformation model;

[0021] Performing Park transformation on the three-phase rectifier current loop working model to determine the three-phase rectifier current loop working transformation model;

[0022] The output DC voltage loop working model of the rectifier bridge in the rectifier is subjected to Park transformation to determine the output DC voltage loop working conversion model of the rectifier bridge in the rectifier; wherein the three-phase rectifier loop working conversion model includes the three-phase rectifier voltage loop working conversion model, the three-phase rectifier current loop working conversion model and the output DC voltage loop working conversion model.

[0023] Optionally, a disturbance signal separation is performed on each variable in the three-phase rectifier loop working transformation model, and a three-phase rectifier disturbance signal model is determined in combination with a preset disturbance current signal;

[0024] Under the condition of unit power factor, performing disturbance signal separation on each variable in the three-phase rectifier voltage loop working conversion model to determine a first disturbance signal model and a first steady-state signal model;

[0025] Under the condition of unit power factor, performing disturbance signal separation on each variable in the three-phase rectifier current loop working transformation model to determine a second disturbance signal model and a second steady-state model, and determining a third disturbance signal model according to the second disturbance signal model and the preset disturbance current signal;

[0026] Under the condition of unit power factor, performing disturbance signal separation on each variable in the output DC voltage loop working conversion model to determine a fourth disturbance signal model;

[0027] The three-phase rectifier disturbance signal model is determined according to the first disturbance signal model, the first steady-state signal model, the third disturbance signal model, the second steady-state model and the fourth disturbance signal model.

[0028] Optionally, determining a three-phase rectifier disturbance signal closed-loop control model includes:

[0029] Based on the three-phase rectifier output disturbance voltage signal and the reference disturbance voltage signal, a voltage outer loop control is performed to determine the reference d-axis disturbance current signal;

[0030] Performing current inner loop control according to the reference d-axis disturbance current signal and the d-axis disturbance current signal to determine a reference d-axis disturbance voltage signal;

[0031] Determine a disturbance duty cycle signal model of the output d-axis switch tube according to the reference d-axis disturbance voltage signal, the d-axis disturbance voltage signal, the AC side inductance parameter, the frequency parameter of the Parker transformation, and the q-axis disturbance current signal;

[0032] Determine a reference q-axis disturbance voltage signal by performing current inner loop control on the reference q-axis disturbance current signal and the q-axis disturbance current signal;

[0033] The disturbance duty cycle signal model of the output q-axis switch tube is determined according to the reference q-axis disturbance voltage signal, the q-axis disturbance voltage signal, the AC side inductance parameter, the frequency parameter of the Parker transformation, and the d-axis disturbance current signal.

[0034] Optionally, a three-phase rectifier output impedance model is determined according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model;

[0035] Determining a three-phase rectifier disturbance voltage and current signal conversion model according to the disturbance duty cycle signal model of the d-axis switch tube, the disturbance duty cycle signal model of the output q-axis switch tube, and the three-phase rectifier disturbance signal model;

[0036] The three-phase rectifier output impedance model is determined by integrating the three-phase rectifier disturbance voltage-current signal conversion model.

[0037] In a second aspect, an embodiment of the present invention further provides a three-phase rectifier output impedance modeling device considering a DC side LC filter unit, the device comprising:

[0038] An acquisition module, used to acquire structural parameters of a three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitance parameters in an LC filter unit, inductance parameters in an LC filter unit, and load resistance parameters;

[0039] A loop model building module, used to build a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law;

[0040] A loop transformation model building module, used for performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model;

[0041] A disturbance signal model building module, used for separating disturbance signals of various variables in the three-phase rectifier loop working transformation model, and combining a preset disturbance current signal to determine the three-phase rectifier disturbance signal model;

[0042] A closed-loop control model is established to determine a closed-loop control model of a three-phase rectifier disturbance signal;

[0043] The output impedance model determination module is used to determine the output impedance model of the three-phase rectifier according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model.

[0044] In a third aspect, an embodiment of the present invention further provides a computer device, the computer device comprising:

[0045] at least one processor; and

[0046] a memory communicatively connected to the at least one processor; wherein,

[0047] The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the three-phase rectifier output impedance modeling method considering the DC side LC filtering unit described in the first aspect.

[0048] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the three-phase rectifier output impedance modeling method considering the DC side LC filter unit described in the first aspect when executed.

[0049] The embodiment of the present invention obtains the structural parameters of a three-phase rectifier; establishes a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law; performs Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model; performs disturbance signal separation on each variable in the three-phase rectifier loop working transformation model, and determines the three-phase rectifier disturbance signal model in combination with a preset disturbance current signal; determines the three-phase rectifier disturbance signal closed-loop control model; determines the three-phase rectifier output impedance model according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model, thereby realizing accurate modeling of the output impedance of the three-phase PWM rectifier containing an LC filter unit through a dq-axis Park linearization conversion method. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a flow chart of a method for modeling output impedance of a three-phase rectifier considering a DC side LC filter unit provided by an embodiment of the present invention;

[0051] Figure 2 is a circuit topology diagram of a three-phase rectifier considering a DC side LC filter unit in an embodiment of the present invention;

[0052] Figure 3 It is a flow chart of another method for modeling output impedance of a three-phase rectifier considering a DC side LC filter unit provided by an embodiment of the present invention;

[0053] Figure 4 is a structural diagram of a three-phase rectifier closed-loop control system provided by an embodiment of the present invention;

[0054] Figure 5 It is a process diagram of establishing a three-phase rectifier disturbance voltage and current signal conversion model and performing integration processing on the three-phase rectifier disturbance voltage and current signal conversion model provided by an embodiment of the present invention;

[0055] Figure 6 is a relationship diagram between a simulated output impedance spectrum of a three-phase rectifier provided by an embodiment of the present invention and a theoretical output impedance spectrum of the three-phase rectifier obtained based on a sweep frequency meter;

[0056] Figure 7 It is a structural schematic diagram of a three-phase rectifier output impedance modeling device considering a DC side LC filter unit provided by an embodiment of the present invention;

[0057] Figure 8 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0059] Figure 1 1 is a flow chart of a method for modeling the output impedance of a three-phase rectifier considering a DC side LC filter unit provided by an embodiment of the present invention. This embodiment is applicable to modeling the output impedance of a three-phase rectifier containing an LC filter unit. The method can be performed by a device for modeling the output impedance of a three-phase rectifier considering a DC side LC filter unit, such as Figure 1 As shown, the method specifically comprises the following steps:

[0060] S110, obtaining structural parameters of a three-phase rectifier;

[0061] in, Figure 2 is a circuit topology diagram of a three-phase rectifier considering a DC side LC filter unit in an embodiment of the present invention; Figure 2 As shown, the three-phase rectifier includes a three-phase AC side filter inductor L, IGBT controllable devices Sau, Sbu, Scu; a three-phase PWM rectifier circuit composed of Sad, Sbd, Scd, an LC filter unit composed of an inductor L0 and a capacitor C, and a DC load resistor R; Vga, Vgb, Vgc are the grid voltages input to the three-phase rectifier; ia, ib, ic are the currents flowing from the AC side grid into the PWM rectifier circuit; va, vb, vc are the single-phase voltages modulated by the PWM rectifier circuit; v0 is the DC voltage output by the PWM rectifier circuit; idc is the DC current output by the PWM rectifier circuit; vdc is the voltage across the filter capacitor C; Sa, Sb, Sc are the switching states of the three-phase bridge arm devices in the three-phase PWM rectifier circuit.

[0062] The structural parameters of the three-phase rectifier include an AC side inductance parameter L, a capacitance parameter C in an LC filter unit, an inductance parameter L0 in an LC filter unit, and a load resistance parameter R.

[0063] S120. According to Kirchhoff's law, a three-phase rectifier circuit working model is established based on structural parameters;

[0064] Among them, according to Kirchhoff's law, the three-phase rectifier circuit working model can be established based on the structural parameters, that is, the grid voltage Vga, Vgb, Vgc; the current ia, ib, ic flowing into the PWM rectifier circuit; the single-phase phase voltage va, vb, vc modulated by the PWM rectifier circuit, the DC voltage v0 output by the PWM rectifier circuit, the DC voltage idc output by the PWM rectifier circuit, the voltage vdc across the filter capacitor C, the switching states Sa, Sb, Sc of the three-phase bridge arm devices and the mathematical relationship between the structural parameters.

[0065] S130, performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model;

[0066] Among them, the Park transformation is to convert a three-phase symmetrical stationary coordinate system into a dq coordinate system that rotates synchronously with the fundamental frequency of the power grid; the Park transformation is performed on the three-phase rectifier loop working model, that is, the time-varying AC quantities in the three-phase symmetrical stationary coordinate system in the three-phase rectifier loop working model are converted into variables in the dq coordinate system that rotates synchronously with the fundamental frequency of the power grid; the variables in the three-phase rectifier loop working transformation model determined by the Park transformation of the three-phase rectifier loop working model are the DC quantities in the dq coordinate system that rotates synchronously with the fundamental frequency of the power grid; the Park transformation is performed on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model, which can simplify the design of the subsequent three-phase rectifier disturbance signal closed-loop control model.

[0067] Specifically, the three-phase rectifier circuit working transformation model is a model obtained by performing Park transformation on the grid voltages Vga, Vgb, Vgc in the three-phase rectifier circuit working model; the currents ia, ib, ic flowing into the PWM rectifier circuit; the single-phase voltages va, vb, vc modulated by the PWM rectifier circuit; and the switching states Sa, Sb, Sc of the three-phase bridge arm devices.

[0068] S140, performing disturbance signal separation on each variable in the three-phase rectifier loop working transformation model, and combining a preset disturbance current signal to determine a three-phase rectifier disturbance signal model;

[0069] Among them, the variables in the three-phase rectifier circuit working transformation model can be used Replace with is the disturbance signal; X is the steady-state signal; each variable in the three-phase rectifier loop working transformation model can be converted into a small signal disturbance superimposed on the steady-state working point; in the conversion process, the square term of the disturbance signal can be ignored, the existing disturbance signal component is retained, and the three-phase rectifier disturbance signal model can be obtained by combining with the preset disturbance current signal; the preset disturbance current signal is the disturbance current signal flowing into the LC filter unit.

[0070] S150, determining a three-phase rectifier disturbance signal closed-loop control model;

[0071] Among them, the three-phase rectifier disturbance signal closed-loop control model can be established based on the three-phase rectifier closed-loop control system; the three-phase rectifier closed-loop control system is a control system composed of a voltage outer loop and a current inner loop; in the three-phase rectifier closed-loop control system, the output voltage is measured and compared with a given reference voltage, and then the switch state of each bridge arm device of the three phases is adjusted to make the output voltage as close to the given reference voltage as possible. Similarly, in the three-phase rectifier disturbance signal closed-loop control model, the output disturbance voltage signal is measured and compared with a given reference disturbance voltage, and then the switch state of each bridge arm device of the three phases is adjusted to make the output disturbance voltage as close to the given reference disturbance voltage as possible.

[0072] S160, determining a three-phase rectifier output impedance model according to a three-phase rectifier disturbance signal model and a three-phase rectifier disturbance signal closed-loop control model.

[0073] Among them, combining the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model can determine the three-phase rectifier disturbance voltage and current signal conversion model; the three-phase rectifier disturbance voltage and current signal conversion model is a model between the disturbance current signal and the disturbance voltage signal, and then according to the three-phase rectifier disturbance voltage and current signal conversion model, the three-phase rectifier output impedance model can be determined; the three-phase rectifier output impedance model is a model for establishing the ratio of the disturbance voltage signal to the disturbance current signal.

[0074] The embodiment of the present invention obtains the structural parameters of a three-phase rectifier; establishes a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law; performs Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model; performs disturbance signal separation on each variable in the three-phase rectifier loop working transformation model, and determines the three-phase rectifier disturbance signal model in combination with a preset disturbance current signal; determines the three-phase rectifier disturbance signal closed-loop control model; determines the three-phase rectifier output impedance model according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model, so as to realize accurate modeling of the output impedance of the three-phase PWM rectifier containing an LC filter unit through a dq-axis Park linearization conversion method.

[0075] Optionally, based on the above method embodiment, each step of establishing the output impedance model of the three-phase rectifier is further refined, and the method for establishing the output impedance model of the three-phase rectifier is further optimized. Figure 3 FIG. 1 is a flow chart of another method for modeling output impedance of a three-phase rectifier considering a DC side LC filter unit provided by an embodiment of the present invention. Figure 3 As shown, the method comprises the following steps:

[0076] S210, obtaining structural parameters of a three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitance parameters in an LC filter unit, inductance parameters in an LC filter unit, and load resistance parameters;

[0077] S220. According to Kirchhoff's law, a three-phase rectifier circuit working model is established based on structural parameters;

[0078] Specifically, according to Kirchhoff's law, a three-phase rectifier circuit working model is established based on structural parameters, including:

[0079] 1) According to Kirchhoff's voltage law, a three-phase rectifier voltage loop working model is established based on structural parameters; the three-phase rectifier voltage loop working model is specifically as follows:

[0080]

[0081] Among them, combined Figure 2 , Vga, Vgb, Vgc are grid voltages; ia, ib, ic are currents flowing into the PWM rectifier circuit; va, vb, vc are single-phase voltages modulated by the PWM rectifier circuit; v0 is the DC voltage output by the PWM rectifier circuit; Sa, Sb, Sc are the switching states of the three-phase bridge arm devices; L is the AC side inductance parameter;

[0082] It should be noted that for the sake of simplicity of analysis, the switching states Sa, Sb, and Sc of the three-phase bridge arm devices are defined as;

[0083] S ip +S in =1,i∈{a,b,c}

[0084] S i =S ip =1-S in ,i∈{a,b,c}

[0085] Then the switch states Sa, Sb, and Sc are averaged to obtain the duty cycle function of each bridge arm device of the three phases, thereby obtaining a switch state continuous model;

[0086]

[0087] That is, the switching state of each bridge arm device of the three-phase can also be expressed as da, db, or dc.

[0088] 2) According to Kirchhoff's current law, a three-phase rectifier current loop working model is established based on the structural parameters; the three-phase rectifier current loop working model is specifically:

[0089]

[0090] Wherein, idc is the DC voltage output by the PWM rectifier circuit; vdc is the voltage across the filter capacitor C; C is the capacitance parameter in the LC filter unit; R is the load resistance parameter;

[0091] 3) Determine the output DC voltage loop working model of the rectifier bridge in the three-phase rectifier according to the current loop working model of the three-phase rectifier; the output DC voltage loop working model is specifically:

[0092]

[0093] Among them, v0 is the DC voltage output by the PWM rectifier circuit; L0 is the inductance parameter in the LC filter unit.

[0094] It can be understood that the three-phase rectifier circuit working model includes the three-phase rectifier voltage circuit working model, the three-phase rectifier current circuit working model and the output DC voltage circuit working model of the rectifier bridge in the three-phase rectifier; that is, the three-phase rectifier circuit working model is a set of simultaneous equations of equations (1), (2) and (3).

[0095] S230, performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model;

[0096] The Parker transformation is specifically:

[0097]

[0098] Performing Park transformation on the three-phase rectifier circuit working model to determine the three-phase rectifier circuit working transformation model includes:

[0099] 1) Perform Park transformation on the three-phase rectifier voltage loop working model (the above formula (1)) to determine the three-phase rectifier voltage loop working transformation model; the three-phase rectifier voltage loop working transformation model is specifically:

[0100]

[0101] Among them, id and iq are the currents ia, ib and ic flowing into the PWM rectifier circuit after Park transformation; Vgd and Vgq are the voltages corresponding to the grid voltages Vga, Vgb and Vgc after Park transformation; v0 is the DC voltage output by the PWM rectifier circuit; dd and dq are the switching states Sa, Sb and Sc of the three-phase bridge arm devices after Park transformation; w is the fundamental frequency of the grid;

[0102] 2) Perform Park transformation on the three-phase rectifier current loop working model (the above formula (2)) to determine the three-phase rectifier current loop working transformation model; the three-phase rectifier current loop working transformation model is specifically:

[0103]

[0104] Wherein, vdc is the voltage across the filter capacitor C;

[0105] 3) Performing Park transformation on the output DC voltage loop working model of the rectifier bridge in the rectifier (the above formula (3)) to determine the output DC voltage loop working transformation model of the rectifier bridge in the rectifier; the output DC voltage loop working transformation model is specifically:

[0106]

[0107] It can be understood that the three-phase rectifier circuit working conversion model includes the three-phase rectifier voltage circuit working conversion model (the above formula (5)), the three-phase rectifier current circuit working conversion model (the above formula (6)) and the output DC voltage circuit working conversion model (the above formula (7)); that is, the three-phase rectifier circuit working conversion model is a set of simultaneous equations of the above formula (5), the above formula (6) and the above formula (7).

[0108] S240, performing disturbance signal separation on each variable in the three-phase rectifier loop working transformation model, and combining a preset disturbance current signal to determine a three-phase rectifier disturbance signal model;

[0109] Specifically, the disturbance signal of each variable in the three-phase rectifier loop working transformation model is separated, and the three-phase rectifier disturbance signal model is determined by combining the preset disturbance current signal, including:

[0110] 1) Under the condition of unit power factor (v gq =0,i q =0), the disturbance signal separation is performed on each variable in the three-phase rectifier voltage loop working transformation model (the above formula (5)) to determine the first disturbance signal model and the first steady-state signal model; that is, Will Substituting the above formula (5) to separate the disturbance signal, we can obtain the first disturbance signal model and the first steady-state signal model; the first disturbance signal model is specifically:

[0111]

[0112] The first steady-state signal model is specifically:

[0113] V o =V dc

[0114]

[0115] 2) Under the condition of unit power factor (v gq =0,i q =0), the disturbance signal separation is performed on each variable in the three-phase rectifier current loop working transformation model (the above formula (6)) to determine the second disturbance signal model and the second steady-state model. The second disturbance signal model is specifically:

[0116]

[0117] The second steady-state model is as follows:

[0118]

[0119]

[0120] 3) Determine the third disturbance signal model according to the second disturbance signal model (formula (10) above) and the preset disturbance current signal; the third disturbance signal model is specifically:

[0121]

[0122] in, is a preset disturbance current signal; is the disturbance current signal flowing into the LC filter unit, which can be a sinusoidal disturbance current of different frequencies.

[0123] 4) Under unity power factor condition (v gq =0,i q =0), performing disturbance signal separation on each variable in the output DC voltage loop working transformation model (the above formula (7)) to determine a fourth disturbance signal model;

[0124]

[0125] 5) Determine the disturbance signal model of the three-phase rectifier according to the first disturbance signal model (formula (8) above), the first steady-state signal model (formula (9) above), the third disturbance signal model (formula (12) above), the second steady-state model (formula (11) above) and the fourth disturbance signal model (formula (13) above); the disturbance signal model of the three-phase rectifier is obtained by substituting the known quantities of formulas (9) and (11) into formula (12), and then combining formulas (8), (12) and (13) above.

[0126] S250, determining a three-phase rectifier disturbance signal closed-loop control model;

[0127] in, Figure 4 is a structural diagram of a three-phase rectifier closed-loop control system provided by an embodiment of the present invention; a three-phase rectifier disturbance signal closed-loop control model can be based on Figure 4 The three-phase rectifier closed-loop control system shown is established; specifically, a three-phase rectifier disturbance signal closed-loop control model is determined, including:

[0128] Based on the three-phase rectifier output disturbance voltage signal With the reference disturbance voltage signal Perform voltage outer loop control to determine the reference d-axis disturbance current signal Specifically:

[0129]

[0130] Among them, G v (s) is the voltage outer loop control PI parameter;

[0131] G v (s) = k vp +k vi / s

[0132] kvp is the proportional gain, kvi is the integral gain;

[0133] According to the reference d-axis disturbance current signal and the d-axis disturbance current signal Perform current inner loop control to determine the reference d-axis disturbance voltage signal

[0134]

[0135] According to the reference d-axis disturbance voltage signal d-axis disturbance voltage signal AC side inductance parameter L, Parker transform frequency parameter w, q-axis disturbance current signal Determine the disturbance duty cycle signal model of the output d-axis switch tube; specifically:

[0136]

[0137] Among them, G i (s) is the current inner loop control PI parameter;

[0138] G i (s) = k ip +k ii / s,

[0139] k ip is the proportional gain, k ii is the integral gain.

[0140] According to the reference q-axis perturbation current signal and the q-axis disturbance current signal Perform current inner loop control to determine the reference q-axis disturbance voltage signal

[0141]

[0142] According to the reference q-axis disturbance voltage signal Q-axis disturbance voltage signal AC side inductance parameter L, Parker transform frequency parameter w, d-axis disturbance current signal Determine the disturbance duty cycle signal model of the output q-axis switch tube.

[0143]

[0144] S260: Determine a three-phase rectifier output impedance model according to a three-phase rectifier disturbance signal model and a three-phase rectifier disturbance signal closed-loop control model.

[0145] Specifically, determining the output impedance model of the three-phase rectifier according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model includes:

[0146] 1) Determine the three-phase rectifier disturbance voltage and current signal conversion model according to the disturbance duty cycle signal model of the d-axis switch tube (the above formula (15)), the disturbance duty cycle signal model of the output q-axis switch tube (the above formula (16)) and the three-phase rectifier disturbance signal model;

[0147] Among them, the three-phase rectifier disturbance voltage and current signal conversion model is more specifically determined by performing Laplace transform on the above equation (8), substituting the above equations (14)-(16) into the above equation (8) after Laplace transform, and combining the above equation (13) to obtain:

[0148]

[0149]

[0150] Among them, r is the internal resistance of the transmission line in the power grid; s is the complex variable in the Laplace transform, which represents the frequency in the Laplace transform domain; s represents the response of the system to input signals of different frequencies. The value of s can be a real number or an imaginary number, depending on the characteristics of the system. By analyzing the different values ​​of s, we can understand the response characteristics of the system at different frequencies.

[0151] If you Then formula (18) can be transformed into the following formula (19);

[0152]

[0153] Substituting the above equations (17) and (19) into the above equation (12), we finally get the three-phase rectifier disturbance voltage and current signal conversion model; the three-phase rectifier disturbance voltage and current signal conversion model is about the preset disturbance current signal With disturbance voltage signal Models of the relationships between

[0154] 2) Integrate the three-phase rectifier disturbance voltage and current signal conversion model to determine the three-phase rectifier output impedance model.

[0155] Figure 5 1 is a process diagram of establishing a three-phase rectifier disturbance voltage and current signal conversion model and performing integration processing on the three-phase rectifier disturbance voltage and current signal conversion model provided by an embodiment of the present invention; Figure 5 As shown, the output impedance model of the three-phase rectifier is determined according to the three-phase rectifier disturbance voltage and current signal conversion model after integration processing:

[0156]

[0157] Where A1 = sC + 1 / R

[0158]

[0159]

[0160] S270, obtaining a theoretical output impedance spectrum of a three-phase rectifier based on a frequency sweeper;

[0161] The working principle of the sweep frequency meter is to add a small disturbance when the system is working in a steady state and simultaneously detect its voltage response in the system; thus, based on the sweep frequency meter, the theoretical output impedance spectrum of the three-phase rectifier under the disturbance current signal at different frequencies can be obtained.

[0162] S280, simulating and calculating the output impedance model of the three-phase rectifier to determine the simulated output impedance spectrum of the three-phase rectifier;

[0163] S290. Adjust the structural parameters of the three-phase rectifier or the control parameters in the three-phase rectifier disturbance signal closed-loop control model according to the theoretical output impedance spectrum and the simulated output impedance spectrum.

[0164] in, Figure 6 : is a relationship diagram between the simulated output impedance spectrum of the three-phase rectifier provided by the embodiment of the present invention and the theoretical output impedance spectrum of the three-phase rectifier obtained based on the sweep frequency meter; Figure 6 As shown, when the simulated output impedance spectrum deviates greatly from the theoretical output impedance spectrum, the structural parameters of the three-phase rectifier or the control parameters in the closed-loop control model of the three-phase rectifier disturbance signal can be adjusted, and the three-phase rectifier output impedance model can be returned to be simulated and calculated again to redetermine the simulated output impedance spectrum of the three-phase rectifier until the simulated output impedance spectrum of the three-phase rectifier is consistent with the theoretical output impedance spectrum of the three-phase rectifier obtained based on the sweep frequency instrument. In this way, a high-precision three-phase rectifier output impedance model is established through iterative optimization of various structural parameters based on the sweep frequency method; and when the simulated output impedance spectrum deviates greatly from the theoretical output impedance spectrum, there is no need to adjust the structural parameters of the three-phase rectifier, nor is there any need to adjust the control parameters in the closed-loop control model of the three-phase rectifier disturbance signal. In this way, the accuracy of the initially established three-phase rectifier output impedance model is verified by the sweep frequency method.

[0165] An embodiment of the present invention also provides a three-phase rectifier output impedance modeling device considering the DC side LC filter unit. The device can execute a three-phase rectifier output impedance modeling method considering the DC side LC filter unit provided by any embodiment of the present invention, and has functional modules and beneficial effects corresponding to the execution method. Figure 7 is a schematic diagram of the structure of a three-phase rectifier output impedance modeling device considering a DC side LC filter unit provided by an embodiment of the present invention, such as Figure 7 As shown, the device comprises:

[0166] The acquisition module 10 is used to acquire the structural parameters of the three-phase rectifier; wherein the structural parameters of the three-phase rectifier include the inductance parameters of the AC side, the capacitance parameters in the LC filter unit, the inductance parameters in the LC filter unit and the load resistance parameters;

[0167] A loop model building module 20 is used to build a three-phase rectifier loop working model based on Kirchhoff's law and structural parameters;

[0168] A loop transformation model building module 30 is used to perform Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model;

[0169] The disturbance signal model building module 40 is used to separate the disturbance signal of each variable in the three-phase rectifier loop working transformation model, and determine the three-phase rectifier disturbance signal model in combination with the preset disturbance current signal;

[0170] A closed-loop control model building model 50 is used to determine a three-phase rectifier disturbance signal closed-loop control model;

[0171] The output impedance model determination module 60 is used to determine the output impedance model of the three-phase rectifier according to the disturbance signal model of the three-phase rectifier and the closed-loop control model of the disturbance signal of the three-phase rectifier.

[0172] Figure 8 is a structural schematic diagram of an electronic device provided by an embodiment of the present invention, Figure 8 A schematic diagram of the structure of an electronic device 100 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0173] like Figure 8 As shown, the electronic device 100 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 100 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0174] A number of components in the electronic device 100 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 100 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0175] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The processor 11 executes the various methods and processes described above, such as a three-phase rectifier output impedance modeling method considering a DC side LC filter unit.

[0176] In some embodiments, a method for modeling the output impedance of a three-phase rectifier considering a DC side LC filter unit may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 100 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method XXX described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform the method XXX in any other appropriate manner (e.g., by means of firmware).

[0177] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0178] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0179] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0180] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0181] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0182] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0183] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0184] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0185] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A three-phase rectifier output impedance modeling method considering a DC side LC filter unit, characterized in that: include: Obtaining structural parameters of a three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitance parameters in an LC filter unit, inductance parameters in an LC filter unit, and load resistance parameters; According to Kirchhoff's law, a three-phase rectifier circuit working model is established based on the structural parameters; Performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model; Separating disturbance signals of variables in the three-phase rectifier loop working transformation model, and combining preset disturbance current signals to determine a three-phase rectifier disturbance signal model; Determine the closed-loop control model of the disturbance signal of the three-phase rectifier; A three-phase rectifier output impedance model is determined according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model.

2. The three-phase rectifier output impedance modeling method according to claim 1, characterized in that: Also includes: Based on a frequency sweeper, obtaining a theoretical output impedance spectrum of the three-phase rectifier; Simulating and calculating the output impedance model of the three-phase rectifier to determine a simulated output impedance spectrum of the three-phase rectifier; The structural parameters of the components of the three-phase rectifier or the control parameters in the closed-loop control model of the disturbance signal of the three-phase rectifier are adjusted according to the simulated output impedance spectrum and the theoretical output impedance spectrum.

3. The three-phase rectifier output impedance modeling method according to claim 1, characterized in that: According to Kirchhoff's law, a three-phase rectifier circuit working model is established based on the structural parameters, including: According to Kirchhoff's voltage law, a voltage loop working model of a three-phase rectifier is established based on the structural parameters; According to Kirchhoff's current law, a three-phase rectifier current loop working model is established based on the structural parameters; The output DC voltage loop working model of the rectifier bridge in the three-phase rectifier is determined according to the three-phase rectifier current loop working model; wherein the three-phase rectifier loop working model includes the three-phase rectifier voltage loop working model, the three-phase rectifier current loop working model and the output DC voltage loop working model of the rectifier bridge in the three-phase rectifier.

4. The three-phase rectifier output impedance modeling method according to claim 3, characterized in that: Performing a Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model includes: Performing Park transformation on the three-phase rectifier voltage loop working model to determine the three-phase rectifier voltage loop working transformation model; Performing Park transformation on the three-phase rectifier current loop working model to determine the three-phase rectifier current loop working transformation model; The output DC voltage loop working model of the rectifier bridge in the rectifier is subjected to Park transformation to determine the output DC voltage loop working conversion model of the rectifier bridge in the rectifier; wherein the three-phase rectifier loop working conversion model includes the three-phase rectifier voltage loop working conversion model, the three-phase rectifier current loop working conversion model and the output DC voltage loop working conversion model.

5. The three-phase rectifier output impedance modeling method according to claim 4, characterized in that: Separating disturbance signals of variables in the three-phase rectifier loop working transformation model, and combining preset disturbance current signals to determine a three-phase rectifier disturbance signal model; Under the condition of unit power factor, performing disturbance signal separation on each variable in the three-phase rectifier voltage loop working conversion model to determine a first disturbance signal model and a first steady-state signal model; Under the condition of unit power factor, performing disturbance signal separation on each variable in the three-phase rectifier current loop working transformation model to determine a second disturbance signal model and a second steady-state model, and determining a third disturbance signal model according to the second disturbance signal model and the preset disturbance current signal; Under the condition of unit power factor, performing disturbance signal separation on each variable in the output DC voltage loop working conversion model to determine a fourth disturbance signal model; The three-phase rectifier disturbance signal model is determined according to the first disturbance signal model, the first steady-state signal model, the third disturbance signal model, the second steady-state model and the fourth disturbance signal model.

6. The three-phase rectifier output impedance modeling method according to claim 1, characterized in that: Determine the closed-loop control model of the three-phase rectifier disturbance signal, including: Based on the three-phase rectifier output disturbance voltage signal and the reference disturbance voltage signal, a voltage outer loop control is performed to determine the reference d-axis disturbance current signal; Performing current inner loop control according to the reference d-axis disturbance current signal and the d-axis disturbance current signal to determine a reference d-axis disturbance voltage signal; Determine a disturbance duty cycle signal model of the output d-axis switch tube according to the reference d-axis disturbance voltage signal, the d-axis disturbance voltage signal, the AC side inductance parameter, the frequency parameter of the Parker transformation, and the q-axis disturbance current signal; Determine a reference q-axis disturbance voltage signal by performing current inner loop control on the reference q-axis disturbance current signal and the q-axis disturbance current signal; The disturbance duty cycle signal model of the output q-axis switch tube is determined according to the reference q-axis disturbance voltage signal, the q-axis disturbance voltage signal, the AC side inductance parameter, the frequency parameter of the Parker transformation, and the d-axis disturbance current signal.

7. The three-phase rectifier output impedance modeling method according to claim 6, characterized in that: Determining a three-phase rectifier output impedance model according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model; Determining a three-phase rectifier disturbance voltage and current signal conversion model according to the disturbance duty cycle signal model of the d-axis switch tube, the disturbance duty cycle signal model of the output q-axis switch tube, and the three-phase rectifier disturbance signal model; The three-phase rectifier output impedance model is determined by integrating the three-phase rectifier disturbance voltage-current signal conversion model.

8. A three-phase rectifier output impedance modeling device considering a DC side LC filter unit, characterized in that: include: An acquisition module, used to acquire structural parameters of a three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitance parameters in an LC filter unit, inductance parameters in an LC filter unit, and load resistance parameters; A loop model building module, used to build a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law; A loop transformation model building module, used for performing Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model; A disturbance signal model building module, used for separating disturbance signals of various variables in the three-phase rectifier loop working transformation model, and combining a preset disturbance current signal to determine the three-phase rectifier disturbance signal model; A closed-loop control model is established to determine a closed-loop control model of a three-phase rectifier disturbance signal; The output impedance model determination module is used to determine the output impedance model of the three-phase rectifier according to the three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model.

9. A computer device, characterized in that: The computer device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the three-phase rectifier output impedance modeling method considering the DC side LC filtering unit as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the three-phase rectifier output impedance modeling method considering a DC side LC filter unit according to any one of claims 1 to 7 when executed.

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