A M-based 3 C harmonic circulating current determination method, device, electronic device and storage medium for simplified harmonic circulating current model

Abstract

The present invention discloses a method based on M 3 C harmonic circulating current simplified model of the harmonic circulating current determination method, device, electronic equipment and storage medium, the method comprising: obtaining M 3 C parameters and grid side parameters; among them, M 3 The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain; the parameters on the grid side include the power frequency side frequency, the frequency division side frequency, the power frequency side voltage d-axis component, and the frequency division side voltage d-axis component; according to M 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 The harmonic circulating current of C. By implementing the present invention, the efficiency of determining the harmonic circulating current can be improved.

Description

Technical Field

[0001] The present invention relates to the field of power electronic converters and power system harmonic technology, and in particular to a method based on M 3 C. Method, device, electronic device and storage medium for determining harmonic circulating current of a simplified harmonic circulating current model. Background Art

[0002] Modular Multilevel Matrix Converter (M 3 C) has been widely used in flexible frequency division transmission and other fields due to its unique flexible current conversion capability and high power density characteristics. 3 The complex circuit structure and nonlinear dynamic characteristics of C make it the main source of harmonic circulating currents. These harmonic circulating currents not only aggravate the heating, loss and aging problems of devices, but also threaten the safety and stability of the frequency-divided transmission system. Therefore, it is necessary to accurately determine the M 3 The effective value of the harmonic circulating current of C is not only an important basis for studying the generation and propagation mechanism of harmonics, but also the key to achieving online monitoring and suppression of harmonics, which helps to significantly improve the safety and reliability of the frequency-controlled transmission system.

[0003] In the prior art, a modeling method is usually used to determine M 3 C harmonic circulation, these methods often directly consider all high-order components and complex coupling relationships when building models, aiming to fully characterize M 3 C's internal dynamic characteristics. While this approach can improve the theoretical integrity of the model and the accuracy of its description of harmonic behavior to a certain extent, it significantly increases the complexity of the mathematical model. The model contains a large number of difficult-to-simplify variables and equations, which significantly increases the computational effort. This results in a time-consuming solution and reduces the efficiency of determining the effective value of the harmonic circulating current, thus affecting its application in practical engineering. Summary of the Invention

[0004] The embodiment of the present invention provides a method based on M 3 C. A harmonic circulating current determination method, device, electronic device, and storage medium for a simplified harmonic circulating current model. Implementation of the present invention can improve the efficiency of harmonic circulating current determination.

[0005] An embodiment of the present invention provides a method based on M 3 C. The harmonic circulation current determination method of the simplified harmonic circulation current model includes:

[0006] Get M 3 C parameters and grid side parameters; among them, M 3The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain. The parameters on the grid side include the power frequency side frequency, the split frequency side frequency, the power frequency side voltage d-axis component, and the split frequency side voltage d-axis component.

[0007] According to M 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation;

[0008] Among them, M is constructed by the following method 3 C harmonic circulation simplified model:

[0009] Get M 3 The circuit topology of C;

[0010] Based on Kirchhoff's voltage law, according to the circuit topology, M is constructed. 3 C basic mathematical model;

[0011] Based on the two-dimensional sequence component algorithm, M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model;

[0012] To M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model;

[0013] Generate a bridge arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model;

[0014] Based on M 3 The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

[0015] Furthermore, the M 3 C harmonic circulation simplified model, including:

[0016]

[0017] Among them, i cir_RMS is the effective value of harmonic circulating current; ω S is the power frequency side frequency; n is the number of full-bridge submodules in the bridge arm; C is the submodule capacitance; v Crefis the submodule capacitor voltage reference value; K P is the closed-loop proportional gain; ω is the system angular frequency; e d is the voltage effective value coefficient; L arm is the bridge arm inductance; x is the frequency ratio between the power frequency side and the divided frequency side; Q is the reactive power; and P is the active power.

[0018] Furthermore, based on Kirchhoff's voltage law, according to the circuit topology, M is constructed. 3 C basic mathematical model, including:

[0019] Based on Kirchhoff's voltage law and the circuit topology, a dynamic voltage balance equation, a bridge arm voltage equation, and a submodule capacitor voltage dynamic equation are generated;

[0020] According to the dynamic voltage balance equation, bridge arm voltage equation and submodule capacitor voltage dynamic equation, M is constructed. 3 C basic mathematical model;

[0021] Among them, the dynamic voltage balance equation is specifically:

[0022]

[0023] Where, is the rate of change of the bridge arm current; I is the bridge arm current matrix; U S is the power frequency system voltage matrix; U L is the voltage matrix of the frequency division system; V is the bridge arm output voltage matrix; v N is the voltage difference between the neutral points of the two systems; B is the bridge arm distribution matrix;

[0024] The bridge arm voltage equation is specifically:

[0025] V=n·M*V c

[0026] Where, M is the bridge arm modulation signal matrix; V c is the submodule capacitance voltage matrix;

[0027] The submodule capacitor voltage dynamic equation is specifically:

[0028]

[0029] Where, is the rate of change matrix of the submodule capacitor voltage.

[0030] Furthermore, the M 3C. Two-dimensional sequence component model, including the two-dimensional sequence component expression of the modulation signal, the corresponding relationship between phase sequence and frequency, the definition of variable order, the two-dimensional sequence component expression of the power frequency system voltage, the two-dimensional sequence component expression of the frequency-dividing system voltage, and the two-dimensional sequence component expression of the bridge arm current;

[0031] The two-dimensional sequence component expression of the modulated signal is specifically:

[0032]

[0033] in, is the two-dimensional sequence component of the modulation signal of the power frequency system; ω S is the power frequency angular frequency; PZ is the positive sequence-zero sequence component; is the two-dimensional sequence component of the modulation signal of the frequency division system; ω L is the frequency division angular frequency; ZP is the positive sequence-zero sequence component; It is the positive sequence-zero sequence component of the power frequency system modulation signal on the d axis and q axis; It is the zero-sequence-positive-sequence component of the modulation signal of the frequency division system on the d-axis and q-axis; is the positive-sequence-zero-sequence component of the power frequency system voltage on the d-axis and q-axis; is the zero-sequence-positive-sequence component of the divided-frequency system voltage on the d-axis and q-axis;

[0034] The corresponding relationship between the phase sequence and the frequency is specifically:

[0035]

[0036] Among them, Y is the phase sequence variable in the vertical direction; X is the phase sequence variable in the horizontal direction; k Y(X) is the frequency coefficient; P is the positive sequence component; N is the negative sequence component; Z is the zero sequence component;

[0037] The definition of the variable order is specifically:

[0038] Order=|k X |+|k Y |

[0039] Among them, Order is the order of the variable; k X is the frequency coefficient of the frequency division system; k Y is the frequency coefficient of the power frequency system;

[0040] The two-dimensional sequence component expression of the power frequency system voltage is specifically:

[0041]

[0042] in, is the two-dimensional sequence component representation of the power frequency system voltage;

[0043] The two-dimensional sequence component expression of the frequency division system voltage is specifically:

[0044]

[0045] in, is the two-dimensional sequence component representation of the frequency division system voltage;

[0046] The two-dimensional sequence component expression of the bridge arm current is specifically:

[0047]

[0048] in, is the two-dimensional sequence component representation of the power frequency system current; is the two-dimensional sequence component representation of the frequency division system current; are the d-axis and q-axis components of the power frequency system current in the rotating coordinate system; are the d-axis and q-axis components of the frequency division system current in the rotating coordinate system.

[0049] Furthermore, the M 3 C ripple coupling model, including;

[0050]

[0051] in, For the frequency (k Y +1)ω S +k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The capacitor voltage ripple, the component under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S -(k X -1)ω L The capacitor voltage ripple, the component under the serial number Y (XP); At frequency k Y ω S +k X ω LThe current component of , the value under the serial number YX; At frequency k Y ω S -k X ω L The current component of the current, the value under the serial number YX; Add(·) is the forward coupling operator; Sub(·) is the reverse coupling operator; is the forward coupling transformation term based on the positive-sequence-zero-sequence component of the power frequency modulation signal; is the forward coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal; is the reverse coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal;

[0052] The M 3 C harmonic coupling model, including:

[0053]

[0054] in, At frequency k Y ω S +k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The current component of , the value under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S -(k X +1)ω L The current component of , the value under the serial number Y(XP); For the frequency C(k Y ω S +k X ω L ) capacitor voltage ripple, the component under the serial number YX; For the frequency C(k Y ω S -k X ω L ) capacitor voltage ripple, the component under serial number YX.

[0055] Furthermore, the bridge arm voltage expression includes:

[0056]

[0057] Among them, V z is the bridge arm voltage component; The frequency is 2ω S +ω L , the voltage component of the bridge arm with phase sequence NP; The frequency is 2ω S -ω L , the bridge arm voltage component with phase sequence NN; The frequency is ω S +2ω L , the bridge arm voltage component with phase sequence PN; The frequency is ω S -2ω L , the bridge arm voltage component with phase sequence PP.

[0058] Furthermore, the harmonic circulation expression includes:

[0059]

[0060] in, is the effective value of the harmonic circulating current component with frequency ω1; is the effective value of the harmonic circulating current component with frequency ω2; is the effective value of the harmonic circulating current component with frequency ω3; is the effective value of the harmonic circulating current component with a frequency of ω4.

[0061] Based on the above method embodiments, the present invention provides corresponding device embodiments.

[0062] An embodiment of the present invention provides a harmonic circulating current determination device based on the M3C harmonic circulating current simplified model, comprising: a parameter acquisition module, a model construction module, and a model derivation module;

[0063] The parameter acquisition module is used to obtain M 3 C parameters and grid side parameters; among them, M 3 The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain. The parameters on the grid side include the power frequency side frequency, the split frequency side frequency, the power frequency side voltage d-axis component, and the split frequency side voltage d-axis component.

[0064] The model building module is used to 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation;

[0065] The model derivation module is used to obtain M 3 C circuit topology; Based on Kirchhoff's voltage law, according to the circuit topology, construct M 3 C basic mathematical model; based on two-dimensional sequence component algorithm, eliminating M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model; for M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model; generating a bridge arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model; based on M 3 The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

[0066] Based on the above method embodiment, the present invention provides a corresponding electronic device embodiment.

[0067] An embodiment of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, it can implement the harmonic circulating current determination method based on the M3C harmonic circulating current simplified model described in any one of the above method embodiments.

[0068] Based on the above method embodiment, the present invention provides a corresponding storage medium embodiment.

[0069] An embodiment of the present invention provides a storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for determining harmonic circulating current based on the simplified M3C harmonic circulating current model described in any one of the above method embodiments can be implemented.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] The embodiment of the present invention provides a method based on M 3 C harmonic circulating current simplified model of harmonic circulating current determination method, device, electronic device and storage medium. The method obtains M 3 C related parameters and grid side parameters, including M 3The number of bridge arm submodules, inductance, capacitance, voltage reference value and closed-loop proportional gain of the C element, the frequency and voltage d-axis component of the grid side. Based on these parameters, according to the preset M 3 C harmonic circulation simplified model, determine M 3 The harmonic circulation of C. This invention is based on the two-dimensional sequence component algorithm, eliminating M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C simplify the M 3 C basic mathematical model, thereby effectively reducing the complexity of the model. At the same time, based on M 3 The power relationship and voltage characteristics in the steady state of C simplify the bridge arm voltage expression, so that the harmonic circulating current model can determine the harmonic circulating current more quickly while maintaining accuracy, solving the problems of large calculation amount and time-consuming solution process in the existing technology, and improving the efficiency of harmonic circulating current determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 An embodiment of the present invention provides a method based on M 3 C. Schematic diagram of the flow chart of the harmonic circulating current determination method for the simplified harmonic circulating current model.

[0073] Figure 2 M provided by an embodiment of the present invention 3 Circuit topology diagram of C.

[0074] Figure 3 This is a construction M provided by an embodiment of the present invention. 3 C. Flowchart of the simplified harmonic circulation model.

[0075] Figure 4 M provided by an embodiment of the present invention 3 C harmonic circulating current electromagnetic transient simulation and M 3 C. Comparison of the results of determining harmonic circulation using the simplified harmonic circulation model.

[0076] Figure 5 1 is a schematic structural diagram of a harmonic circulating current determining device based on the M3C harmonic circulating current simplified model provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0077] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0078] like Figure 1As shown, an embodiment of the present invention provides a method for determining harmonic circulating current based on the simplified M3C harmonic circulating current model, which includes at least the following steps:

[0079] Step S1: Get M 3 Parameters of C and grid side parameters;

[0080] Specifically, M 3 The parameters of the C component include the number of full-bridge sub-modules in the bridge arm, the bridge arm inductance, the sub-module capacitance, the sub-module capacitance voltage reference value, and the closed-loop proportional gain; the parameters on the grid side include the power frequency side frequency, the divided frequency side frequency, the power frequency side voltage d-axis component, and the divided frequency side voltage d-axis component.

[0081] Step S2: According to M 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation.

[0082] In a preferred embodiment, M is constructed by 3 C harmonic circulation simplified model:

[0083] Step S2.1: Get M 3 The circuit topology of C;

[0084] Specifically, M 3 The circuit topology diagram of C is as follows Figure 2 As shown,

[0085] Step S2.2: Based on Kirchhoff's voltage law and the circuit topology, construct M 3 C basic mathematical model;

[0086] Step S2.3: Based on the two-dimensional sequence component algorithm, remove M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model;

[0087] It should be noted here that the two-dimensional sequence component method is briefly introduced below.

[0088] During normal operation, M 3 There are a series of steady-state capacitor voltage harmonics and bridge arm voltage / current harmonics in each bridge arm of C. 3Due to the symmetry of the C circuit topology, the same ripple or harmonic component has the same frequency and amplitude in different bridge arms, but different phase angles. Therefore, the phasor method can be used to express the distribution of ripple / harmonics in different bridge arms by using the phase shift of phasors of the same frequency and amplitude relative to a common reference phasor (such as the phasor corresponding to bridge arm au as the reference). The general expression for the M3C electrical quantity phasor matrix using the two-dimensional sequence component method is:

[0089]

[0090] in, is the two-dimensional sequence component of the electrical quantity phasor matrix with a frequency of ω; YX is the two-dimensional phase sequence, and the phase sequences Y and X can be positive sequence P, zero sequence Z, and negative sequence N; Sd and Sq are the d-axis and q-axis components of the AC electrical quantity respectively; A YX is the phase shift angle matrix, and the value of each element is -2π / 3, 0, or 2π / 3.

[0091] According to the definition of positive and negative zero sequence, nine two-dimensional phase shift angle matrices A YX The expression is:

[0092]

[0093] Based on the principle of multiplication and addition between phasors, the operation rules of two-dimensional sequence components are as follows:

[0094] (1) Addition

[0095] Two-dimensional sequence matrix with the same angular frequency and phase angle Addition operations can be performed, and the result is the sum of the corresponding terms of the d and q axis components:

[0096]

[0097] (2) Multiplication

[0098] The two-dimensional sequence component After multiplying by the constant a, the result is:

[0099]

[0100] (3) Phase angle offset

[0101]

[0102] (4) Angular velocity reversal

[0103] When the angular velocity is rotated in the opposite direction, that is, when the angular frequency is -ω, after changing the direction of rotation, the d-axis component remains unchanged, the q-axis component takes the opposite number, and the two-dimensional phase sequence is opposite to the original phase sequence:

[0104]

[0105] The operation rules for phase sequence inversion d are:

[0106] P=-N,N=-P,Z=-Z

[0107] (5) Differentiation

[0108] For two-dimensional order components Differentiating it yields:

[0109]

[0110] (6) Phase multiplication

[0111] The two two-dimensional sequence components Multiplying them gives:

[0112]

[0113] The addition operation rule between phase sequences is:

[0114] P+P=N,P+N=Z,P+Z=P

[0115] N+N=P,N+Z=Z,Z+Z=Z

[0116] Step S2.4, for M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model;

[0117] Step S2.5: Generate an arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model;

[0118] Step S2.6, based on M 3 The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

[0119] In a preferred embodiment, the M 3 C harmonic circulation simplified model, including:

[0120]

[0121] Among them, i cir_BMS is the effective value of harmonic circulating current; ω S is the power frequency side frequency; n is the number of full-bridge submodules in the bridge arm; C is the submodule capacitance; v Cref is the submodule capacitor voltage reference value; K Pis the closed-loop proportional gain; ω is the system angular frequency; e d is the voltage effective value coefficient; L arm is the bridge arm inductance; x is the frequency ratio between the power frequency side and the divided frequency side; Q is the reactive power; and P is the active power.

[0122] In an optional embodiment, based on Kirchhoff's voltage law, according to the circuit topology, M is constructed. 3 C basic mathematical model, including:

[0123] Based on Kirchhoff's voltage law and the circuit topology, a dynamic voltage balance equation, a bridge arm voltage equation, and a submodule capacitor voltage dynamic equation are generated;

[0124] According to the dynamic voltage balance equation, bridge arm voltage equation and submodule capacitor voltage dynamic equation, M is constructed. 3 C basic mathematical model;

[0125] Among them, the dynamic voltage balance equation is specifically:

[0126]

[0127] Where, is the rate of change of the bridge arm current; I is the bridge arm current matrix; U S is the power frequency system voltage matrix; U L is the voltage matrix of the frequency division system; V is the bridge arm output voltage matrix; v N is the voltage difference between the neutral points of the two systems; B is the bridge arm distribution matrix;

[0128] The bridge arm voltage equation is specifically:

[0129] V=n·M*V c

[0130] Where, M is the bridge arm modulation signal matrix; V c is the submodule capacitance voltage matrix;

[0131] The submodule capacitor voltage dynamic equation is specifically:

[0132]

[0133] Where, is the rate of change matrix of the submodule capacitor voltage.

[0134] Specifically, the M 3 C. Two-dimensional sequence component model, including the two-dimensional sequence component expression of the modulation signal, the corresponding relationship between phase sequence and frequency, the definition of variable order, the two-dimensional sequence component expression of the power frequency system voltage, the two-dimensional sequence component expression of the frequency-dividing system voltage, and the two-dimensional sequence component expression of the bridge arm current;

[0135] The two-dimensional sequence component expression of the modulated signal is specifically:

[0136]

[0137] in, is the two-dimensional sequence component of the modulation signal of the power frequency system; ω S is the power frequency angular frequency; PZ is the positive sequence-zero sequence component; is the two-dimensional sequence component of the modulation signal of the frequency division system; ω L is the frequency division angular frequency; ZP is the positive sequence-zero sequence component; It is the positive sequence-zero sequence component of the power frequency system modulation signal on the d axis and q axis; It is the zero-sequence-positive-sequence component of the modulation signal of the frequency division system on the d-axis and q-axis; is the positive-sequence-zero-sequence component of the power frequency system voltage on the d-axis and q-axis; is the zero-sequence-positive-sequence component of the divided-frequency system voltage on the d-axis and q-axis;

[0138] The corresponding relationship between the phase sequence and the frequency is specifically:

[0139]

[0140] Among them, Y is the phase sequence variable in the vertical direction; X is the phase sequence variable in the horizontal direction; k Y(X) is the frequency coefficient; P is the positive sequence component; N is the negative sequence component; Z is the zero sequence component;

[0141] The definition of the variable order is specifically:

[0142] Order=|k X |+|k Y |

[0143] Among them, Order is the order of the variable; k X is the frequency coefficient of the frequency division system; k Y is the frequency coefficient of the power frequency system;

[0144] The two-dimensional sequence component expression of the power frequency system voltage is specifically:

[0145]

[0146] in, is the two-dimensional sequence component representation of the power frequency system voltage;

[0147] The two-dimensional sequence component expression of the frequency division system voltage is specifically:

[0148]

[0149] in, is the two-dimensional sequence component representation of the frequency division system voltage;

[0150] The two-dimensional sequence component expression of the bridge arm current is specifically:

[0151]

[0152] in, is the two-dimensional sequence component representation of the power frequency system current; is the two-dimensional sequence component representation of the frequency division system current; are the d-axis and q-axis components of the power frequency system current in the rotating coordinate system; are the d-axis and q-axis components of the frequency division system current in the rotating coordinate system.

[0153] It should be noted that the two-dimensional sequence component expression of the submodule capacitor voltage can be obtained from the two-dimensional sequence component expression of the bridge arm current and the two-dimensional sequence component expression of the modulation signal according to the above-mentioned submodule capacitor voltage dynamic equation. The two-dimensional sequence component expression of the bridge arm voltage can be obtained from the two-dimensional sequence component expression of the submodule capacitor voltage and the two-dimensional sequence component expression of the modulation signal according to the above-mentioned bridge arm voltage equation.

[0154] Preferably, the M 3 C. Two-dimensional sequence component model, including the two-dimensional sequence component expression of the modulation signal, the corresponding relationship between phase sequence and frequency, the definition of variable order, the two-dimensional sequence component expression of the power frequency system voltage, the two-dimensional sequence component expression of the frequency-dividing system voltage, and the two-dimensional sequence component expression of the bridge arm current;

[0155] The two-dimensional sequence component expression of the modulated signal is specifically:

[0156]

[0157] in, is the two-dimensional sequence component of the modulation signal of the power frequency system; ω S is the power frequency angular frequency; PZ is the positive sequence-zero sequence component; is the two-dimensional sequence component of the modulation signal of the frequency division system; ω L is the frequency division angular frequency; ZP is the positive sequence-zero sequence component; It is the positive sequence-zero sequence component of the power frequency system modulation signal on the d axis and q axis; It is the zero-sequence-positive-sequence component of the modulation signal of the frequency division system on the d-axis and q-axis; is the positive-sequence-zero-sequence component of the power frequency system voltage on the d-axis and q-axis; is the zero-sequence-positive-sequence component of the divided-frequency system voltage on the d-axis and q-axis;

[0158] The corresponding relationship between the phase sequence and the frequency is specifically:

[0159]

[0160] Among them, Y is the phase sequence variable in the vertical direction; X is the phase sequence variable in the horizontal direction; k Y(X) is the frequency coefficient; P is the positive sequence component; N is the negative sequence component; Z is the zero sequence component;

[0161] The definition of the variable order is specifically:

[0162] Order=|k X |+|k Y |

[0163] Among them, Order is the order of the variable; k X is the frequency coefficient of the frequency division system; k Y is the frequency coefficient of the power frequency system;

[0164] The two-dimensional sequence component expression of the power frequency system voltage is specifically:

[0165]

[0166] in, is the two-dimensional sequence component representation of the power frequency system voltage;

[0167] The two-dimensional sequence component expression of the frequency division system voltage is specifically:

[0168]

[0169] in, is the two-dimensional sequence component representation of the frequency division system voltage;

[0170] The two-dimensional sequence component expression of the bridge arm current is specifically:

[0171]

[0172] in, is the two-dimensional sequence component representation of the power frequency system current; is the two-dimensional sequence component representation of the frequency division system current; are the d-axis and q-axis components of the power frequency system current in the rotating coordinate system; are the d-axis and q-axis components of the frequency division system current in the rotating coordinate system.

[0173] In a preferred embodiment, the M 3 C ripple coupling model, including;

[0174]

[0175]

[0176] in, For the frequency (k Y +1)ω S +k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The capacitor voltage ripple, the component under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S -(k X +1)ω L The capacitor voltage ripple, the component under the serial number Y (XP); At frequency k Y ω S -k X ω L The current component of , the value under the serial number YX; At frequency k Y ω S -k X ω L The current component of the current, the value under the serial number YX; Add(·) is the forward coupling operator; Sub(·) is the reverse coupling operator; is the forward coupling transformation term based on the positive-sequence-zero-sequence component of the power frequency modulation signal; is the forward coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal; is the reverse coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal;

[0177] It should be noted that Add(·) is a forward coupling operator used to positively superimpose the power frequency and the frequency division sideband components to compensate for the orthogonal phase offset; Sub(·) is a reverse coupling operator used to reversely offset the impedance voltage drop on the frequency division side and eliminate the phase error of the reverse coupling path; is a forward coupling transformation term based on the positive-sequence-zero-sequence components of the power frequency modulation signal, which is used to convert the modulation signal of the power frequency system (including the positive-sequence and zero-sequence components) into a coupling term that drives the harmonic circulating current through the matrix operation of the forward coupling operator Add(·); is a forward coupling transformation term based on the zero-sequence and positive-sequence components of the frequency division modulation signal, which is used to convert the modulation signal (including the zero-sequence and positive-sequence components) of the frequency division system into a coupling term that drives the harmonic circulating current through the matrix operation of the forward coupling operator Add(·); is a reverse coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal, which is used to convert the zero-sequence-positive sequence component of the modulation signal on the frequency division side into a coupling term that suppresses harmonic circulating current through the matrix operation of the reverse coupling operator Sub(·);

[0178] Optionally, the steady-state value of the capacitor voltage ripple component of each submodule is:

[0179]

[0180] The M 3 C harmonic coupling model, including:

[0181]

[0182] in, At frequency k Y ω S +k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The current component of , the value under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S -(k X +1)ω L The current component of , the value under the serial number Y(XP); For the frequency C(k Y ω S +k X ω L ) capacitor voltage ripple, the component under the serial number YX; For the frequency C(k Y ω S +k X ω L ) capacitor voltage ripple, the component under serial number YX.

[0183] Alternatively, the dq components of the steady-state current harmonics can be expressed as:

[0184]

[0185] Among them, L eq is the loop reactance of the corresponding sequence network.

[0186] Preferably, the harmonic circulation expression includes:

[0187]

[0188] in, is the effective value of the harmonic circulating current component with frequency ω1; is the effective value of the harmonic circulating current component with frequency ω2; is the effective value of the harmonic circulating current component with frequency ω3; is the effective value of the harmonic circulating current component with a frequency of ω4.

[0189] Bridge arm voltage effective value υ ω_RMS The expression is:

[0190]

[0191] When adopting the harmonic circulating current closed-loop proportional suppression strategy, the effective value of the harmonic circulating current of a frequency i ω_RMS for:

[0192]

[0193] Preferably, the bridge arm voltage expression is:

[0194]

[0195] Among them, V z To show the bridge arm voltage component that will excite harmonic circulating current, including Four components;

[0196] It should be noted here that since the impact of the 4th order and above high-order harmonics / ripple components on the frequency-divided transmission system is very small and can be ignored, only the 3rd order and below harmonics / ripple components will be considered in the following. 3 The bridge arm voltage expression of C is as above, where only the circulating current components with phase sequences of NP, NN, PN, and PP are extracted.

[0197] Optional, M 3 When C is in steady state, the q-axis voltage is 0, that is, u Sq =u Lq = 0. At this time, the active and reactive power of the power frequency and frequency division systems can be expressed as:

[0198]

[0199] Define the ratio of the angular frequency on the power frequency side to the angular frequency on the divided frequency side as ω S :ω L =x:1. The analysis shows that the maximum value of the harmonic circulating current appears at M 3 When the power frequency side and the frequency division side absorb or emit the same reactive power, u Sd =u Ld =u d , Q S =Q L =Q. In describing M 3 When the active power of C on the power frequency side and the split frequency side is equal in magnitude but opposite in direction, if the converter loss is ignored, either one of them can be used. In this article, P is used to represent the active power on the power frequency side, and the active power on the split frequency side is -P.

[0200] The simplified expression of the bridge arm voltage is specifically:

[0201]

[0202]

[0203] Where b1=1 / (36nω S C sm (v Cref ) 2 ).

[0204] Given that the frequency of the frequency-dividing transmission demonstration project currently in operation is 20Hz, an approximate simplified expression of the harmonic circulating current under this frequency scenario is given. When the frequency-dividing frequency is 20Hz, that is, ω S :ω L =5∶2, the bridge arm voltage is:

[0205]

[0206] The simplified expression of the effective value of harmonic circulating current in this frequency scenario is i cir_RMS for:

[0207]

[0208] In one embodiment, to verify the accuracy of the proposed method and model, the present invention conducts a verification experiment based on the parameters shown in the following table:

[0209]

[0210]

[0211] Specifically, according to the above steps, the harmonic circulating current electromagnetic transient simulation model and the harmonic circulating current approximate simplified model are established respectively, and the output results of the two models are compared, such as Figure 4 As shown. Figure 4 It can be seen that the difference between the established harmonic circulating current approximate simplified model and the electromagnetic transient simulation model is very small, and the harmonic circulating current waveform can be accurately and effectively fitted, which verifies the accuracy of the established model and the correctness of the proposed modeling method.

[0212] Based on the above method embodiments, the present invention provides corresponding device embodiments.

[0213] like Figure 5 As shown, an embodiment of the present invention provides a method based on M 3 C. A harmonic circulation determination device for a simplified harmonic circulation model, comprising: a parameter acquisition module, a model construction module, and a model derivation module;

[0214] The parameter acquisition module is used to obtain M 3 C parameters and grid side parameters; among them, M 3 The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain. The parameters on the grid side include the power frequency side frequency, the split frequency side frequency, the power frequency side voltage d-axis component, and the split frequency side voltage d-axis component.

[0215] The model building module is used to 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation;

[0216] The model derivation module is used to obtain M 3 C circuit topology; Based on Kirchhoff's voltage law, according to the circuit topology, construct M 3 C basic mathematical model; based on two-dimensional sequence component algorithm, eliminating M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model; for M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model; generating a bridge arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model; based on M 3The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

[0217] It should be noted that the embodiment of the device described above corresponds to the above-mentioned embodiment of the present invention, and it can implement any of the above-mentioned methods for determining harmonic circulation based on the simplified M3C harmonic circulation model of the present invention. In addition, the embodiment of the above-mentioned device is merely schematic, wherein the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the embodiment of the device provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which can be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement it without paying any creative work.

[0218] Based on the above method embodiment of the present invention, a corresponding electronic device embodiment is provided.

[0219] An embodiment of the present invention provides an electronic device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the harmonic circulating current determination method based on the M3C harmonic circulating current simplified model described in any one of the present invention is implemented, or when the processor executes the computer program, the functions of the modules in the above-mentioned device embodiments are implemented.

[0220] Exemplarily, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device.

[0221] The terminal device may be a computing device such as a desktop computer, a notebook computer, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0222] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, connecting various parts of the entire terminal device using various interfaces and lines.

[0223] The memory can be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function, etc.; the data storage area can store data created based on the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0224] Based on the above method embodiment, the present invention provides a corresponding storage medium embodiment;

[0225] Another embodiment of the present invention provides a storage medium, which includes a stored computer program. When the computer program is executed, the device where the storage medium is located is controlled to execute any one of the above-mentioned harmonic circulating current determination methods based on the M3C harmonic circulating current simplified model of the present invention.

[0226] The above-mentioned storage medium is a computer-readable storage medium, and the computer program includes computer program code, which may be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0227] In the description of this specification, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and integrate different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0228] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method based on M 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: include: Get M 3 C parameters and grid side parameters; among them, M 3 The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain. The parameters on the grid side include the power frequency side frequency, the split frequency side frequency, the power frequency side voltage d-axis component, and the split frequency side voltage d-axis component. According to M 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation; Among them, M is constructed by the following method 3 C harmonic circulation simplified model: Get M 3 The circuit topology of C; Based on Kirchhoff's voltage law, according to the circuit topology, M is constructed. 3 C basic mathematical model; Based on the two-dimensional sequence component algorithm, M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model; To M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model; Generate a bridge arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model; Based on M 3 The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

2. The M-based method according to claim 1 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: The M 3 C harmonic circulation simplified model, including: Among them, i cir_RMS is the effective value of harmonic circulating current; ω s is the power frequency side frequency; n is the number of full-bridge submodules in the bridge arm; C is the submodule capacitance; v Cref is the submodule capacitor voltage reference value; K P is the closed-loop proportional gain; ω is the system angular frequency; e d is the voltage effective value coefficient; L arm is the bridge arm inductance; x is the frequency ratio between the power frequency side and the divided frequency side; Q is the reactive power; and P is the active power.

3. The M-based method according to claim 2 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: Based on Kirchhoff's voltage law, according to the circuit topology, M is constructed. 3 C basic mathematical model, including: Based on Kirchhoff's voltage law and the circuit topology, a dynamic voltage balance equation, a bridge arm voltage equation, and a submodule capacitor voltage dynamic equation are generated; According to the dynamic voltage balance equation, bridge arm voltage equation and submodule capacitor voltage dynamic equation, M is constructed. 3 C basic mathematical model; Among them, the dynamic voltage balance equation is specifically: Where, is the rate of change of the bridge arm current; I is the bridge arm current matrix; U S is the power frequency system voltage matrix; U L is the voltage matrix of the frequency division system; V is the bridge arm output voltage matrix; v N is the voltage difference between the neutral points of the two systems; B is the bridge arm distribution matrix; The bridge arm voltage equation is specifically: V=n·M*V c Where, M is the bridge arm modulation signal matrix; V c is the submodule capacitance voltage matrix; The submodule capacitor voltage dynamic equation is specifically: Where, is the rate of change matrix of the submodule capacitor voltage.

4. The M-based method according to claim 3 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: The M 3 C. Two-dimensional sequence component model, including the two-dimensional sequence component expression of the modulation signal, the corresponding relationship between phase sequence and frequency, the definition of variable order, the two-dimensional sequence component expression of the power frequency system voltage, the two-dimensional sequence component expression of the frequency-dividing system voltage, and the two-dimensional sequence component expression of the bridge arm current; The two-dimensional sequence component expression of the modulated signal is specifically: in, is the two-dimensional sequence component of the modulation signal of the power frequency system; ω s is the power frequency angular frequency; PZ is the positive sequence-zero sequence component; is the two-dimensional sequence component of the modulation signal of the frequency division system; ω L is the frequency division angular frequency; ZP is the positive sequence-zero sequence component; It is the positive sequence-zero sequence component of the power frequency system modulation signal on the d axis and q axis; It is the zero-sequence-positive-sequence component of the modulation signal of the frequency division system on the d-axis and q-axis; is the positive-sequence-zero-sequence component of the power frequency system voltage on the d-axis and q-axis; is the zero-sequence-positive-sequence component of the divided-frequency system voltage on the d-axis and q-axis; The corresponding relationship between the phase sequence and the frequency is specifically: Among them, Y is the phase sequence variable in the vertical direction; X is the phase sequence variable in the horizontal direction; k Y(X) is the frequency coefficient; P is the positive sequence component; N is the negative sequence component; Z is the zero sequence component; The definition of the variable order is specifically: Order=|k X |+|k Y | Among them, Order is the order of the variable; k X is the frequency coefficient of the frequency division system; k Y is the frequency coefficient of the power frequency system; The two-dimensional sequence component expression of the power frequency system voltage is specifically: in, is the two-dimensional sequence component representation of the power frequency system voltage; The two-dimensional sequence component expression of the frequency division system voltage is specifically: in, is the two-dimensional sequence component representation of the frequency division system voltage; The two-dimensional sequence component expression of the bridge arm current is specifically: in, is the two-dimensional sequence component representation of the power frequency system current; is the two-dimensional sequence component representation of the frequency division system current; are the d-axis and q-axis components of the power frequency system current in the rotating coordinate system; are the d-axis and q-axis components of the frequency division system current in the rotating coordinate system.

5. The M-based method according to claim 4 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: The M 3 C ripple coupling model, including; in, For the frequency (k Y +1)ω s +k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The capacitor voltage ripple, the component under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The capacitor voltage ripple, the component under the serial number (Y+P)X; At frequency k Y ω S -(k X +1)ω L The capacitor voltage ripple, the component under the serial number Y (XP); At frequency k Y ω S +k X ω L The current component of , the value under the serial number YX; At frequency k Y ω S -k X ω L The current component of the current, the value under the serial number YX; Add(·) is the forward coupling operator; Sub(·) is the reverse coupling operator; is the forward coupling transformation term based on the positive-sequence-zero-sequence component of the power frequency modulation signal; is the forward coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal; is the reverse coupling transformation term based on the zero-sequence-positive sequence component of the frequency division modulation signal; The M 3 C harmonic coupling model, including: in, At frequency k Y ω S +k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S +(k X +1)ω L The current component of , the value under the serial number Y(X+P); For the frequency (k Y +1)ω S -k X ω L The current component of , the value under the serial number (Y+P)X; At frequency k Y ω S -(k X +1)ω L The current component of , the value under the serial number Y(XP); For the frequency C(k Y ω S +k X ω L ) capacitor voltage ripple, the component under the serial number YX; For the frequency C(k Y ω S -k X ω L ) capacitor voltage ripple, the component under serial number YX.

6. The M-based method according to claim 5 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: The bridge arm voltage expression includes: Among them, V z is the bridge arm voltage component; The frequency is 2ω S +ω L , the voltage component of the bridge arm with phase sequence NP; The frequency is 2ω S -ω L , the bridge arm voltage component with phase sequence NN; The frequency is ω S +2ω L , the bridge arm voltage component with phase sequence PN; The frequency is ω S -2ω L , the bridge arm voltage component with phase sequence PP.

7. The M-based method according to claim 6. 3 C. A method for determining harmonic circulating currents of a simplified harmonic circulating current model, characterized in that: The harmonic circulation expression includes: in, is the effective value of the harmonic circulating current component with frequency ω1; is the effective value of the harmonic circulating current component with frequency ω2; is the effective value of the harmonic circulating current component with frequency ω3; is the effective value of the harmonic circulating current component with a frequency of ω4.

8. A method based on M 3 C. A harmonic circulating current determining device of a simplified harmonic circulating current model, characterized in that: include: Parameter acquisition module, model construction module and model derivation module; The parameter acquisition module is used to obtain M 3 C parameters and grid side parameters; among them, M 3 The parameters of the C component include the number of full-bridge submodules, bridge arm inductance, submodule capacitance, submodule capacitance voltage reference value, and closed-loop proportional gain. The parameters on the grid side include the power frequency side frequency, the split frequency side frequency, the power frequency side voltage d-axis component, and the split frequency side voltage d-axis component. The model building module is used to 3 The parameters of the C element and the grid side parameters are based on the preset M 3 C harmonic circulation simplified model, determine M 3 C's harmonic circulation; The model derivation module is used to obtain M 3 C circuit topology; Based on Kirchhoff's voltage law, according to the circuit topology, construct M 3 C basic mathematical model; based on two-dimensional sequence component algorithm, eliminating M 3 The high-order ripple components, harmonic components and bridge arm impedance voltage drop in the basic mathematical model of C generate M 3 C two-dimensional sequence component model; for M 3 C two-dimensional sequence component model to perform ripple coupling analysis and harmonic coupling analysis, generate M 3 C ripple coupling model and M 3 C harmonic coupling model; generating a bridge arm voltage expression and a harmonic circulating current expression according to the ripple coupling model and the harmonic coupling model; based on M 3 The power relationship and voltage characteristics of C in steady state are used to simplify the bridge arm voltage expression and generate the simplified bridge arm voltage expression; through the simplified bridge arm voltage expression, the harmonic circulating current expression is simplified to generate M 3 C Simplified model of harmonic circulation.

9. An electronic device, characterized in that: comprising a memory, a processor, and a computer program stored in the memory and operable on the processor; when the processor executes the computer program, the method according to any one of claims 1 to 7 based on M 3 C. Method for determining harmonic circulating current of simplified harmonic circulating current model.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it can realize the M-based 3 C. Method for determining harmonic circulating current of simplified harmonic circulating current model.

Images