A three-phase rectifier output impedance modeling method, device and equipment considering a DC side LC filter unit and a medium

Abstract

The application discloses a three-phase rectifier output impedance modeling method, device and equipment considering a DC side LC filter unit and a medium. The method comprises the following steps: obtaining structural parameters of each component of a three-phase rectifier; establishing a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law; determining a three-phase rectifier loop working conversion model by performing Park transformation on the three-phase rectifier loop working model; separating each variable in the three-phase rectifier loop working conversion model from a disturbance signal, and combining a preset disturbance current signal to determine a three-phase rectifier disturbance signal model; 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. The scheme realizes accurate modeling of the output impedance of the three-phase rectifier containing the LC filter unit through a d-q axis Park linearization conversion method.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the technical field of three-phase rectifiers, and particularly relates to a three-phase rectifier output impedance modeling method, device, equipment and medium considering a DC side LC filter unit. BACKGROUND

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

[0003] The three-phase PWM rectifier can realize AC / DC conversion and is widely applied in new energy power generation fields such as wind power generation and photovoltaic power generation, and the internal LC filter unit has a certain effect on suppressing the ripple on the DC side and is also often applied on the DC side. Establishing an output impedance model by taking the three-phase PWM rectifier and the DC side LC filter unit as a whole and applying the impedance stability criterion to analyze the system stability is a method for improving the system stability, and therefore the impedance modeling of the three-phase PWM rectifier containing the LC filter unit is crucial. At present, the accuracy of the impedance modeling of the three-phase PWM rectifier containing the LC filter unit is poor. SUMMARY

[0004] The application provides a three-phase rectifier output impedance modeling method, device, equipment and medium considering a DC side LC filter unit, and the d-q axis park linearization conversion method is used to realize accurate modeling of the output impedance of the three-phase PWM rectifier containing the LC filter unit.

[0005] To achieve the above object, in a first aspect, the embodiment of the application provides a three-phase rectifier output impedance modeling method considering a DC side LC filter unit, which comprises the following steps:

[0006] obtaining structure parameters of a three-phase rectifier; wherein the structure parameters of the three-phase rectifier comprise AC side inductance parameters, capacitor parameters in an LC filter unit, inductance parameters in the LC filter unit and load resistance parameters;

[0007] establishing a three-phase rectifier loop working model based on the structure parameters according to Kirchhoff's law;

[0008] performing park transformation on the three-phase rectifier loop working model to determine a three-phase rectifier loop working transformation model;

[0009] The disturbance signal of each variable in the three-phase rectifier loop working transformation model is separated, and a preset disturbance current signal is combined to determine a three-phase rectifier disturbance signal model;

[0010] A three-phase rectifier disturbance signal closed-loop control model is determined.

[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 comprises: obtaining a theoretical output impedance spectrum of the three-phase rectifier based on a frequency sweeper;

[0013] A simulation output impedance spectrum of the three-phase rectifier is determined by simulating the three-phase rectifier output impedance model;

[0014] According to the simulation output impedance spectrum and the theoretical output impedance spectrum, the structure parameters of each component of the three-phase rectifier or the control parameters in the three-phase rectifier disturbance signal closed-loop control model are adjusted.

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

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

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

[0018] According to the three-phase rectifier current loop working model, an output DC voltage loop working model of a rectifier bridge in the three-phase rectifier is determined; wherein the three-phase rectifier loop working model comprises 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, a three-phase rectifier loop working transformation model is determined by performing a Park transformation on the three-phase rectifier loop working model, comprising:

[0020] A three-phase rectifier voltage loop working transformation model is determined by performing a Park transformation on the three-phase rectifier voltage loop working model;

[0021] A three-phase rectifier current loop working transformation model is determined by performing a Park transformation on the three-phase rectifier current loop working model;

[0022] performing park transformation on the output direct current voltage loop working model of the rectifier bridge in the rectifier to determine a rectifier bridge output direct current voltage loop working transformation model; wherein the three-phase rectifier loop working transformation model comprises the three-phase rectifier voltage loop working transformation model, the three-phase rectifier current loop working transformation model and the output direct current voltage loop working transformation model.

[0023] Optionally, the perturbation signal separation is performed on each variable in the three-phase rectifier loop working transformation model, and a preset perturbation current signal is combined to determine a three-phase rectifier perturbation signal model.

[0024] Under the condition of unit power factor, the perturbation signal separation is performed on each variable in the three-phase rectifier voltage loop working transformation model to determine a first perturbation signal model and a first steady-state signal model.

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

[0026] Under the condition of unit power factor, the perturbation signal separation is performed on each variable in the output direct current voltage loop working transformation model to determine a fourth perturbation signal model.

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

[0028] Optionally, a three-phase rectifier perturbation signal closed-loop control model is determined, comprising:

[0029] The voltage outer loop control is performed based on the three-phase rectifier output perturbation voltage signal and a reference perturbation voltage signal to determine a reference d-axis perturbation current signal.

[0030] The current inner loop control is performed according to the reference d-axis perturbation current signal and a d-axis perturbation current signal to determine a reference d-axis perturbation voltage signal.

[0031] The perturbation duty cycle signal model of the output d-axis switching tube is determined according to the reference d-axis perturbation voltage signal, a d-axis perturbation voltage signal, an alternating current side inductance parameter, a frequency parameter of park transformation, and a q-axis perturbation current signal.

[0032] The current inner loop control is performed according to the reference q-axis perturbation current signal and the q-axis perturbation current signal to determine a reference q-axis perturbation voltage signal.

[0033] According to the reference q-axis disturbance voltage signal, the q-axis disturbance voltage signal, the alternating current side inductance parameter, the frequency parameter of the Park transformation, and the d-axis disturbance current signal, a disturbance duty cycle signal model of an output q-axis switch tube is determined.

[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] 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, a three-phase rectifier disturbance voltage and current signal conversion model is determined.

[0036] The three-phase rectifier disturbance voltage and current signal conversion model is integrated to determine the three-phase rectifier output impedance model.

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

[0038] An acquisition module is configured to acquire structure parameters of a three-phase rectifier, wherein the structure parameters of the three-phase rectifier include an alternating current side inductance parameter, a capacitor parameter in an LC filter unit, an inductance parameter in the LC filter unit, and a load resistance parameter.

[0039] A loop model establishing module is configured to establish a three-phase rectifier loop working model based on the structure parameters according to Kirchhoff's law.

[0040] A loop transformation model establishing module is configured to determine a three-phase rectifier loop working transformation model by performing a Park transformation on the three-phase rectifier loop working model.

[0041] A disturbance signal model establishing module is configured to separate each variable in the three-phase rectifier loop working transformation model into a disturbance signal, and determine a three-phase rectifier disturbance signal model in combination with a preset disturbance current signal.

[0042] A closed-loop control model establishing module is configured to determine a three-phase rectifier disturbance signal closed-loop control model.

[0043] An output impedance model determining module is configured to determine 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.

[0044] In a third aspect, an embodiment of the present application further provides a computer device, which comprises:

[0045] at least one processor; and

[0046] A memory in communication connection with the at least one processor; wherein

[0047] 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 to enable the at least one processor to perform the three-phase rectifier output impedance modeling method considering the LC filter unit on the DC side of the first aspect.

[0048] In a fourth aspect, the embodiments of the present application also provide a computer readable storage medium, which stores computer instructions for enabling a processor to implement the three-phase rectifier output impedance modeling method considering the LC filter unit on the DC side of the first aspect when executed by the processor.

[0049] In the embodiments of the present application, the structure parameters of the three-phase rectifier are obtained; according to Kirchhoff's law, a three-phase rectifier loop working model is established based on the structure parameters; a three-phase rectifier loop working transformation model is determined by performing Park transformation on the three-phase rectifier loop working model; each variable in the three-phase rectifier loop working transformation model is subjected to disturbance signal separation, and a predetermined disturbance current signal is combined to determine a three-phase rectifier disturbance signal model; a three-phase rectifier disturbance signal closed-loop control model is determined; and 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, so that the d-q axis Park linearization conversion method is used to realize accurate modeling of the output impedance of the three-phase PWM rectifier containing the LC filter unit. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a flowchart of a three-phase rectifier output impedance modeling method considering an LC filter unit on the DC side provided by the embodiments of the present application;

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

[0052] Figure 3 is a flowchart of another three-phase rectifier output impedance modeling method considering an LC filter unit on the DC side provided by the embodiments of the present application;

[0053] Figure 4 is a three-phase rectifier closed-loop control system structure diagram provided by the embodiments of the present application;

[0054] Figure 5 is a process diagram for establishing a three-phase rectifier disturbance voltage and current signal conversion model and performing integral processing on the three-phase rectifier disturbance voltage and current signal conversion model provided by the embodiments of the present application;

[0055] Figure 6 is a relationship diagram of a simulation output impedance spectrum of a three-phase rectifier and a theoretical output impedance spectrum of the three-phase rectifier based on a frequency sweeper according to an embodiment of the present application;

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

[0057] Figure 8 is a structural schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0058] The application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0059] Figure 1 is a flowchart of a three-phase rectifier output impedance modeling method considering a DC side LC filter unit according to an embodiment of the present application. The embodiment can be applicable to the modeling of the output impedance of a three-phase rectifier containing an LC filter unit. The method can be performed by a three-phase rectifier output impedance modeling device considering a DC side LC filter unit, as shown in Figure 1 , and specifically includes the following steps:

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

[0061] wherein, Figure 2 is a circuit topology diagram of a three-phase rectifier considering a DC side LC filter unit according to an embodiment of the present application; as shown in Figure 2 , 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 inductor L0 and 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 of the AC side grid flowing into the PWM rectifier circuit; va, vb, vc are the single-phase 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 devices in the three-phase PWM rectifier circuit.

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

[0063] In S120, a three-phase rectifier loop working model is established based on the structural parameters according to the Kirchhoff's law.

[0064] In the three-phase rectifier loop working model, mathematical relationships between the grid voltages Vga, Vgb, and Vgc, the currents ia, ib, and ic flowing into the PWM rectifier circuit, the single-phase phase voltages va, vb, and vc modulated by the PWM rectifier circuit, the DC voltage v0 output by the PWM rectifier circuit, the DC voltage idc across the filter capacitor C, the switching states Sa, Sb, and Sc of the devices in each bridge arm, and the structural parameters are established based on the Kirchhoff's law.

[0065] In S130, a three-phase rectifier loop working transformed model is determined by performing Park transformation on the three-phase rectifier loop working model.

[0066] The Park transformation is a transformation from a three-phase symmetrical stationary coordinate system to a d-q coordinate system that synchronously rotates at the grid fundamental frequency. The Park transformation on the three-phase rectifier loop working model is a transformation of the time-varying alternating quantities in the three-phase symmetrical stationary coordinate system in the three-phase rectifier loop working model into variables in the d-q coordinate system that synchronously rotates at the grid fundamental frequency. The variables in the three-phase rectifier loop working transformed model determined by the Park transformation are the direct quantities in the d-q coordinate system that synchronously rotates at the grid fundamental frequency. The Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformed model can simplify the design of the subsequent three-phase rectifier disturbance signal closed-loop control model.

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

[0068] In S140, disturbance signal separation is performed on the variables in the three-phase rectifier loop working transformed model, and a three-phase rectifier disturbance signal model is determined in combination with a preset disturbance current signal.

[0069] In the three-phase rectifier loop working transformed model, the variables can be replaced by ​is a disturbance signal; X is a steady-state signal; each variable in the working conversion model of the three-phase rectifier loop can be converted into a small signal disturbance superimposed on a steady-state operating 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 the preset disturbance current signal; the preset disturbance current signal is the disturbance current signal flowing into the LC filter unit.

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

[0071] The three-phase rectifier disturbance signal closed-loop control model can be established based on a 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 the given reference voltage, and then the switching state of each bridge arm device of the three-phase is adjusted, so that the output voltage is as close as possible to the given reference voltage. Similarly, in the three-phase rectifier disturbance signal closed-loop control model, the output disturbance voltage signal is measured and compared with the given reference disturbance voltage, and then the switching state of each bridge arm device of the three-phase is adjusted, so that the output disturbance voltage is as close as possible to the given reference disturbance voltage.

[0072] S160, determine 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.

[0073] The three-phase rectifier disturbance signal model and the three-phase rectifier disturbance signal closed-loop control model can be combined to determine a 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 the three-phase rectifier output impedance model can be determined according to the three-phase rectifier disturbance voltage and current signal conversion model; the three-phase rectifier output impedance model is a model of the ratio of the disturbance voltage signal to the disturbance current signal.

[0074] In the embodiment of the present application, the structural parameters of the three-phase rectifier are obtained; according to Kirchhoff's law, the three-phase rectifier loop working model is established based on the structural parameters; the three-phase rectifier loop working conversion model is determined by performing Park transformation on the three-phase rectifier loop working model; the disturbance signal is separated from each variable in the three-phase rectifier loop working conversion model, and the three-phase rectifier disturbance signal model is determined by combining the preset disturbance current signal; the three-phase rectifier disturbance signal closed-loop control model is determined; the 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, so that the d-q axis Park linearization conversion method is used to realize accurate modeling of the output impedance of the three-phase PWM rectifier containing the LC filter unit.

[0075] Optionally, on the basis of the method embodiment, the steps of establishing the output impedance model of the three-phase rectifier are further refined, and the method for establishing the output impedance model of the three-phase rectifier is further optimized, Figure 3 is another flowchart of the method for establishing the output impedance model of the three-phase rectifier considering the LC filter unit provided by the embodiment, as shown in Figure 3 , the method comprises the following steps:

[0076] S210, obtain the structure parameters of the three-phase rectifier; wherein the structure parameters of the three-phase rectifier include AC side inductance parameters, capacitor parameters in the LC filter unit, inductance parameters in the LC filter unit and load resistance parameters;

[0077] S220, according to Kirchhoff's law, establish a three-phase rectifier loop working model based on the structure parameters;

[0078] Specifically, according to Kirchhoff's law, a three-phase rectifier loop working model is established based on the structure parameters, which comprises:

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

[0080]

[0081] Wherein, combined with 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 simplicity of analysis, the switching states Sa, Sb, 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 switching states Sa, Sb, Sc are averaged to obtain the duty cycle function of the three-phase bridge arm devices, so as to obtain a continuous model of the switching state;

[0086]

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

[0088] 2) According to the Kirchhoff's current law, the 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] where idc is the DC voltage output by the PWM rectifier circuit; vdc is the voltage across the filter capacitor C; C is the capacitor parameter in the LC filter unit; R is the load resistance parameter.

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

[0092]

[0093] where 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 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; that is, the three-phase rectifier loop working model is a simultaneous equation group of the above formula (1), the above formula (2), and the above formula (3).

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

[0096] where the Park transformation is specifically:

[0097]

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

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

[0100]

[0101] Wherein, id, iq are the current ia, ib, ic of the flow into the PWM rectifier circuit after the park transformation corresponding current; Vgd, Vgq are the voltage Vga, Vgb, Vgc of the grid after the park transformation corresponding voltage; v0 is the DC voltage output by the PWM rectifier circuit; dd, dq are the switching states Sa, Sb, Sc of the three-phase bridge arm devices after the park transformation corresponding switching state; w is the fundamental frequency of the grid;

[0102] 2), the park transformation is carried out to the three-phase rectifier current loop working model (formula (2) above) 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), the park transformation is carried out to the output DC voltage loop working model (formula (3) above) of the rectifier bridge in the rectifier 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 loop working transformation model includes the three-phase rectifier voltage loop working transformation model (formula (5) above), the three-phase rectifier current loop working transformation model (formula (6) above) and the output DC voltage loop working transformation model (formula (7) above); that is, the three-phase rectifier loop working transformation model is a simultaneous equation group of formula (5) above, formula (6) above and formula (7) above.

[0108] S240, the disturbance signal separation is carried out to each variable in the three-phase rectifier loop working transformation model, and the preset disturbance current signal is combined to determine the three-phase rectifier disturbance signal model;

[0109] Specifically, the disturbance signal separation is carried out to each variable in the three-phase rectifier loop working transformation model, and the preset disturbance current signal is combined to determine the three-phase rectifier disturbance signal model, including:

[0110] 1), under the condition of unity power factor (v gq = 0, i q = 0), the disturbance signal separation is carried out to each variable in the three-phase rectifier voltage loop working transformation model (formula (5) above) to determine the first disturbance signal model and the first steady-state signal model; that is, let Substitute Into formula (5) above to carry out disturbance signal separation, the first disturbance signal model and the first steady-state signal model can be obtained; 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 unity power factor (v gq = 0, i q = 0), the second disturbance signal model and the second steady-state model are determined by performing disturbance signal separation on each variable in the working transformed model (equation (6) above) of the three-phase rectifier current loop, and the second disturbance signal model is specifically:

[0116]

[0117] The second steady-state model is specifically:

[0118]

[0119]

[0120] 3) The third disturbance signal model is determined according to the second disturbance signal model (equation (10) above) and a preset disturbance current signal, and the third disturbance signal model is specifically:

[0121]

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

[0123] 4) Under the condition of unity power factor (v gq = 0, i q = 0), the fourth disturbance signal model is determined by performing disturbance signal separation on each variable in the working transformed model (equation (7) above) of the output DC voltage loop;

[0124]

[0125] 5) Determine the three-phase rectifier disturbance signal model according to the first disturbance signal model (the above formula (8)), the first steady-state signal model (the above formula (9)), the third disturbance signal model (the above formula (12)), the second steady-state model (the above formula (11)) and the fourth disturbance signal model (the above formula (13)); the three-phase rectifier disturbance signal model is that the above formula (9), (11) is substituted into formula (12), and then the equation group after the above formula (8), (12), (13) is associated.

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

[0127] Wherein, Figure 4 is the three-phase rectifier closed-loop control system structure diagram provided by the embodiment of the application; the three-phase rectifier disturbance signal closed-loop control model can be established based on the three-phase rectifier closed-loop control system shown in the figure. Figure 4 Specifically, the three-phase rectifier disturbance signal closed-loop control model is determined, comprising:

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

[0129]

[0130] Wherein, 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, and 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 The AC side inductance parameter L, the frequency parameter w of the park transformation, and the q-axis disturbance current signal Determine the disturbance duty cycle signal model of the output d-axis switching tube; specifically,

[0136]

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

[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 disturbance 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 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 includes:

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

[0147] Among them, the more specific method for determining the three-phase rectifier disturbance voltage and current signal conversion model is to perform Laplace transform on the above equation (8), substitute the above equations (14)-(16) into the above equation (8) after Laplace transform, and combine with the above equation (13) to obtain:

[0148]

[0149]

[0150] Where, r is the transmission line resistance in the power grid; s is a complex variable in Laplace transformation, representing the frequency in the Laplace transformation domain; s represents the response of the system to different frequency input signals. The value of s can be real or imaginary, depending on the characteristics of the system. By analyzing different values of s, the response characteristics of the system at different frequencies can be understood.

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

[0152]

[0153] Substitute the above formula (17) and the above formula (19) into the above formula (12), and finally obtain a three-phase rectifier disturbance voltage and current signal conversion model; the three-phase rectifier disturbance voltage and current signal conversion model is a model about the relationship between the preset disturbance current signal And the disturbance voltage signal ;

[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 The process chart for establishing the three-phase rectifier disturbance voltage and current signal conversion model and integrating the three-phase rectifier disturbance voltage and current signal conversion model is provided in the embodiments of the present application; as shown in Figure 5 The three-phase rectifier output impedance model is determined according to the three-phase rectifier disturbance voltage and current signal conversion model after integration as follows:

[0156]

[0157] Wherein, A1 = sC + 1 / R

[0158]

[0159]

[0160] S270, based on the frequency sweeper, the theoretical output impedance spectrum of the three-phase rectifier is obtained;

[0161] Wherein, the working principle of the frequency sweeper is that when the system is in steady state, a small disturbance is added and the voltage response in the system is detected at the same time; thus, based on the frequency sweeper, the theoretical output impedance spectrum of the three-phase rectifier under the disturbance current signal at different frequencies can be obtained.

[0162] S280, the simulation calculation of the three-phase rectifier output impedance model determines the simulation output impedance spectrum of the three-phase rectifier;

[0163] S290, adjusting the structure parameters of the three-phase rectifier or the control parameters in the three-phase rectifier perturbation signal closed-loop control model according to the theoretical output impedance spectrum and the simulation output impedance spectrum.

[0164] wherein, Figure 6 is a relationship diagram of the simulation output impedance spectrum of the three-phase rectifier provided by the embodiment of the present application and the theoretical output impedance spectrum of the three-phase rectifier based on the frequency sweep instrument; as Figure 6 shown, when the simulation output impedance spectrum and the theoretical output impedance spectrum have a large deviation, the structure parameters of the three-phase rectifier or the control parameters in the three-phase rectifier perturbation signal closed-loop control model can be adjusted, and the simulation calculation of the three-phase rectifier output impedance model is returned to be re-performed to re-determine the simulation output impedance spectrum of the three-phase rectifier, until the simulation output impedance spectrum of the three-phase rectifier is consistent with the theoretical output impedance spectrum of the three-phase rectifier based on the frequency sweep instrument, so that the high-precision three-phase rectifier output impedance model is established through the iteration optimization of each structure parameter based on the frequency sweep method; and when the simulation output impedance spectrum and the theoretical output impedance spectrum have a large deviation, the structure parameters of the three-phase rectifier do not need to be adjusted, and the control parameters in the three-phase rectifier perturbation signal closed-loop control model do not need to be adjusted, so that the accuracy of the three-phase rectifier output impedance model preliminarily established is verified through the frequency sweep method.

[0165] The embodiment of the present application also provides a three-phase rectifier output impedance modeling device considering a DC side LC filter unit, which can perform the three-phase rectifier output impedance modeling method considering the DC side LC filter unit provided by any embodiment of the present application, and has the corresponding function modules and beneficial effects of the performing method. Figure 7 is a structure schematic diagram of a three-phase rectifier output impedance modeling device considering a DC side LC filter unit provided by the embodiment of the present application, as Figure 7 shown, the device comprises:

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

[0167] The loop model establishing module 20 is used to establish the three-phase rectifier loop working model based on the structure parameters according to the Kirchhoff's law.

[0168] The loop transformation model establishing module 30 is used to perform the Park transformation on the three-phase rectifier loop working model to determine the three-phase rectifier loop working transformation model.

[0169] The perturbation signal model establishing module 40 is used to separate each variable in the three-phase rectifier loop working transformation model through the perturbation signal, and combine the preset perturbation current signal to determine the three-phase rectifier perturbation signal model.

[0170] The closed-loop control model establishes a model 50 for determining a three-phase rectifier perturbation signal closed-loop control model;

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

[0172] Figure 8 is a structural schematic diagram of an electronic device provided by an embodiment of the present application, Figure 8 A structural schematic diagram of an electronic device 100 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular telephones, smart phones, wearable devices (e.g., headsets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be examples only, and are not intended to limit the implementations of the present application described and / or claimed in this document.

[0173] As shown in Figure 8 The electronic device 100 includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11, wherein the memory stores a computer program that can be executed by the at least one processor. 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 into 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 plurality 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, a speaker, etc.; a storage unit 18, such as a magnetic 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 can be various general and / or special purpose 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 specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, and the like. The processor 11 performs various methods and processes described above, such as a method of modeling output impedance of a three-phase rectifier considering an LC filter unit at a DC side.

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

[0177] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a programmable logic device (PLD), a computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0178] Computer programs used to implement the methods of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program, when executed by the processor of the machine, implements the functions / acts specified in the flowcharts and / or block diagrams. The computer program can be executed entirely on a machine, partially on a machine, partially on a machine as a stand-alone software package, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0179] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0180] To provide for interaction with a user, the systems and techniques described here can 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 a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0181] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can 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), blockchain network, and the Internet.

[0182] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. A server can 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 large management difficulty and weak business scalability in traditional physical host and VPS service.

[0183] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, each step described in the present application can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0184] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

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

Claims

1. A method of modeling output impedance of a three-phase rectifier considering LC filter units on a DC side, characterized by, The method comprises the following steps: Obtaining the structural parameters of the three-phase rectifier; wherein the structural parameters of the three-phase rectifier include AC side inductance parameters, capacitor parameters in the LC filter unit, inductance parameters in the LC filter unit, and load resistance parameters; According to Kirchhoff's law, a three-phase rectifier loop working model is established based on the structural parameters; Parker transformation is performed on the three-phase rectifier loop working model to determine a three-phase rectifier loop working transformed model; Each variable in the three-phase rectifier loop working transformed model is subjected to disturbance signal separation, and a preset disturbance current signal is combined to determine a three-phase rectifier disturbance signal model; A three-phase rectifier disturbance signal closed-loop control model is determined; The three-phase rectifier disturbance signal closed-loop control model comprises: Voltage outer loop control is performed on the three-phase rectifier output disturbance voltage signal and the reference disturbance voltage signal to determine a reference d-axis disturbance current signal; Current inner loop control is performed on the reference d-axis disturbance current signal and the d-axis disturbance current signal to determine a reference d-axis disturbance voltage signal; The reference d-axis disturbance voltage signal, the d-axis disturbance voltage signal, the AC side inductance parameters, the frequency parameters of the Parker transformation, and the q-axis disturbance current signal are used to determine a disturbance duty cycle signal model of an output d-axis switching tube; Current inner loop control is performed on the reference q-axis disturbance current signal and the q-axis disturbance current signal to determine a reference q-axis disturbance voltage signal; The reference q-axis disturbance voltage signal, the q-axis disturbance voltage signal, the AC side inductance parameters, the frequency parameters of the Parker transformation, and the d-axis disturbance current signal are used to determine a disturbance duty cycle signal model of an output q-axis switching tube; The 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 method of claim 1, wherein, Further comprising: Based on the frequency sweeper, the theoretical output impedance spectrum of the three-phase rectifier is obtained; The three-phase rectifier output impedance model is simulated and calculated to determine the simulation output impedance spectrum of the three-phase rectifier; According to the simulation output impedance spectrum and the theoretical output impedance spectrum, the structural parameters of each component of the three-phase rectifier or the control parameters in the three-phase rectifier disturbance signal closed-loop control model are adjusted.

3. The method of claim 1, wherein, According to Kirchhoff's law, a three-phase rectifier loop working model is established based on the structural parameters, which comprises the following steps: According to Kirchhoff's voltage law, a three-phase rectifier voltage loop working model 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; According to the three-phase rectifier current loop working model, an output DC voltage loop working model of a rectifier bridge in the three-phase rectifier is determined; wherein the three-phase rectifier loop working model comprises 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 method of claim 3, wherein, The Parker transformation is performed on the three-phase rectifier loop working model to determine a three-phase rectifier loop working transformed model, which comprises the following steps: The Parker transformation is performed on the three-phase rectifier voltage loop working model to determine a three-phase rectifier voltage loop working transformed 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 method of claim 4, wherein, Performing disturbance signal separation on each variable in the three-phase rectifier loop working conversion model, and combining the preset disturbance current signal to determine the three-phase rectifier disturbance signal model; Under the condition of unit power factor, performing disturbance signal separation on each variable in the voltage loop working conversion model of the three-phase rectifier to determine a first disturbance signal model and a first steady-state signal model; Under a unit power factor condition, performing disturbance signal separation on each variable in the three-phase rectifier current loop working conversion model to determine a second disturbance signal model and a second steady-state model, and determining a third disturbance signal model based on 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 method of claim 1, wherein, 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-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; An integration process is performed on the three-phase rectifier disturbance voltage-current signal conversion model to determine the three-phase rectifier output impedance model.

7. A device for modeling output impedance of a three-phase rectifier taking into account an LC filter unit on a DC side, characterized by include: An acquisition module is 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 the LC filter unit, inductance parameters in the LC filter unit, and load resistance parameters; A loop model building module, used for building a three-phase rectifier loop working model based on the structural parameters according to Kirchhoff's law; a loop transformation model establishing module, configured to perform 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 is used to separate the disturbance signal of each variable in the three-phase rectifier loop working conversion model and determine the three-phase rectifier disturbance signal model in combination with a preset disturbance current signal; A closed-loop control model is established to determine the closed-loop control model of the three-phase rectifier disturbance signal; 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; determine a reference d-axis disturbance voltage signal according to the reference d-axis disturbance current signal and the d-axis disturbance current signal through current inner loop control; determine an output d-axis switching tube disturbance duty cycle signal model according to the reference d-axis disturbance voltage signal, a d-axis disturbance voltage signal, the AC side inductance parameter, a frequency parameter of the Park transformation, and a q-axis disturbance current signal; determine a reference q-axis disturbance voltage signal according to a reference q-axis disturbance current signal and the q-axis disturbance current signal through current inner loop control; determine an output q-axis switching tube disturbance duty cycle signal model according to the reference q-axis disturbance voltage signal, a q-axis disturbance voltage signal, the AC side inductance parameter, the frequency parameter of the Park transformation, and the d-axis disturbance current signal; determine 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.

8. A computer device, comprising: The computer device comprises: at least one processor; and a memory connected to the at least one processor in communication; 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 to enable the at least one processor to execute the three-phase rectifier output impedance modeling method considering a DC side LC filter unit according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for enabling the processor to implement the three-phase rectifier output impedance modeling method considering a DC side LC filter unit according to any one of claims 1-6 when executed.

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