Multi-field simplified external characteristic simulation modeling method for three-stage generator system

Abstract

The application discloses a three-stage generator system multi-field simplified external characteristic simulation modeling method, and belongs to the field of electric machines.S1: a data table of opposite potential and loss of a main exciter, an auxiliary exciter and a main generator is established;S2: a load side resistance of the main generator, an ambient temperature and a system rotating speed are given;S3: initialization parameters are set;S4: opposite potential b11, b12 and b13 of the auxiliary exciter and rectified current a1' and voltage c1' are obtained;S5: an electric angle position θ2 of the main exciter is calculated;S6: opposite potential b21, b22 and b23 of the main exciter and rectified current a2' and voltage c2' are obtained;S7: an electric angle position θ3 of the main generator is calculated;S8: opposite potential b11, b12 and b13 of the main generator and rectified current a3' and voltage c3' are obtained;S9: system loss is calculated, each winding temperature k of the system is obtained, and Rs1', Rs2', Rs3', Rr2' and Rr3' are calculated;S10: whether Rij-Rij' is less than δ is judged, if Rij-Rij' is greater than δ, S4 to S10 are executed; if Rij-Rij' is less than δ, S11 is executed, and a result is output.The application is used for simulation modeling of a three-stage generator system.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electric machines, and particularly relates to a multi-field simplified external characteristic simulation modeling method for a three-stage generator system. BACKGROUND

[0002] In an aviation system, in order to improve the stability and reliability of a power generation system, a three-stage generator system is usually adopted, which is composed of three parts: a secondary exciter, a primary exciter and a main generator. The secondary exciter is a permanent magnet generator, and a counter electromotive force is generated on the stator winding of the secondary exciter by the rotation of the permanent magnet installed on the rotor. The stator winding of the secondary exciter is connected to the stator winding of the primary exciter through a rectifier bridge. The stator winding of the primary exciter is subjected to the action of direct current to generate a constant magnetic field. The rotor of the primary exciter rotates with the shaft, and the winding of the rotor generates a counter electromotive force. The rotor winding of the primary exciter is connected to the rotor winding of the main generator through a rotating rectifier bridge. The rotor winding of the main generator is subjected to the action of direct current to generate a constant magnetic field and rotates with the shaft, so that the stator winding of the main generator generates a counter electromotive force. After being rectified by a non-controlled rectifier bridge, a direct current voltage is generated for use by the aviation system. However, the temperature of the environment and the rotation speed of the shaft of the aviation system are changing during operation. In order to better understand the performance of the three-stage generator system under different states, it is necessary to evaluate the performance of the three-stage generator system. At present, the main evaluation method is to analyze the three parts of the power generation system by using finite element software. This analysis method has the problems of long time consumption and poor coupling of the current and temperature of the front and rear stages, thereby limiting the performance evaluation of the three-stage generator system. SUMMARY

[0003] The application aims to solve the problem of poor coupling of the current and temperature of the front and rear stages in the performance evaluation and calculation method of the existing three-stage generator system, and proposes a multi-field simplified external characteristic simulation modeling method for a three-stage generator system.

[0004] The method uses finite element calculation to obtain the data of the three parts of the three-stage generator system under different working conditions, and then obtains the performance of the three-stage generator system under a given working condition through iterative interpolation calculation.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0006] A multi-field simplified external characteristic simulation modeling method for a three-stage generator system, the method comprising the following steps:

[0007] Step 1: establishing a counter electromotive force and loss data table of the three-stage generator system, the three-stage generator system comprising a secondary exciter, a primary exciter and a main generator;

[0008] Step 2: giving a working condition of the three-stage generator system, including a main generator load side resistance, an environmental temperature and a rotation speed of the three-stage generator system;

[0009] Step three: set the initial value of the parameters; that is, set the initial value of the electric angle position θ1 of the auxiliary exciter, the load side current a1 of the auxiliary exciter, the load side current a2 of the main exciter and the load side current a3 of the main generator to 0;

[0010] Step four: take the rotating speed of the three-stage generator system, the electric angle position θ1 of the auxiliary exciter and the load side current a1 of the auxiliary exciter as the base value, obtain the corresponding counter electromotive force b11, b12 and b13 in the counter electromotive force data table of the auxiliary exciter by the spline interpolation method, calculate the rectified current a1' and voltage c1' of the auxiliary exciter according to the characteristics of the rectifier bridge according to the obtained counter electromotive force value, the stator winding value Rs1 of the auxiliary exciter under the current environmental temperature and the stator winding value Rs2 of the main exciter under the current environmental temperature;

[0011] Step five: calculate the corresponding electric angle position θ2 of the main exciter;

[0012] Step six: take the rotating speed of the three-stage generator system, the electric angle position θ2 of the main exciter, the rectified current a1' of the auxiliary exciter and the load side current a2 of the main exciter as the base value, obtain the corresponding counter electromotive force b21, b22 and b23 in the counter electromotive force data table of the main exciter by the spline interpolation method, calculate the rectified current a2' and voltage c2' of the main exciter according to the characteristics of the rectifier bridge according to the obtained counter electromotive force value, the rotor winding value Rr2 of the main exciter under the current environmental temperature and the rotor winding value Rr3 of the main generator under the current environmental temperature; the calculation process is the same as that of step four;

[0013] Step seven: calculate the corresponding electric angle position θ3 of the main generator;

[0014] Step eight: take the rotating speed of the three-stage generator system, the electric angle position θ3 of the main generator, the rectified current a2' of the main exciter and the load side current a3 of the main generator as the base value, obtain the corresponding counter electromotive force b31, b32 and b33 in the counter electromotive force data table of the main generator by the spline interpolation method, calculate the rectified current a3' and voltage c3' of the main generator according to the characteristics of the rectifier bridge according to the obtained counter electromotive force value, the stator winding value Rs3 of the generator under the current environmental temperature and the load side resistance value of the main generator; the calculation process is the same as that of step six;

[0015] Step nine: calculate the loss of the three-stage generator system, and put the above loss value P into the lumped thermal circuit equation of the three-stage generator system to obtain the winding temperature k of the three-stage generator system;

[0016] ΔT=QR Tij , Q=hA(T2-T1);

[0017] Wherein: Q is the heat of the thermal circuit, i.e. the loss value P; ΔT is the temperature change of the thermal resistance; R Tij R is the thermal resistance; h is the heat exchange coefficient; A is the heat exchange area; T2 is the temperature of the heat exchange surface; T1 is the ambient temperature;

[0018] And the resistance value Rij' of the winding at the temperature is calculated by the following formula, i = s, r; j = 1, 2, 3; i = r and j = 1 do not exist;

[0019]

[0020] The resistance values Rs1', Rs2', Rs3', Rr2', Rr3' of the winding at the temperature are calculated by the formula, which are the resistance values of Rs1, Rs2, Rs3, Rr2, Rr3 at k degrees Celsius;

[0021] Step ten: difference between the initial resistance value Rij and the calculated Rij' is calculated, and it is determined whether it is less than δ, δ is the convergence error, which is a positive number approaching zero; if the difference is greater than the convergence error δ, the electrical angle position θ1 of the auxiliary exciter is updated, aj' calculated before is used, j = 1, 2, 3, the direct current aj is updated, j here is a symbol, indicating j = 1, 2, 3, the winding resistance value Rij is updated using the winding resistance value Rij' calculated before, and steps four to ten are re-executed until the convergence condition is met; if the difference is less than the convergence error δ, step eleven is continued;

[0022] Step eleven: the electrical angle position θ1 of the auxiliary exciter in the convergence state is taken as 0° to 360°, the performance of the entire three-stage generator system is calculated, and the obtained data is output as the result, including the winding temperature of the three-stage generator system, the direct current aj, the direct voltage of the three-stage generator system, the loss of the three-stage generator system, and the load side power of the main generator.

[0023] Further, step one is specifically:

[0024] The counter electromotive force and the loss of the auxiliary exciter under the action of different speeds, electrical angle positions and load resistances of the auxiliary exciter are calculated by the finite element method, and the calculated results are made into data tables of the counter electromotive force and the loss of the auxiliary exciter with respect to the auxiliary exciter under the action of different speeds, electrical angle positions and load side direct currents, and the corresponding counter electromotive force and loss of the auxiliary exciter under any speed, electrical angle position and direct current within the range of the data table are obtained by spline curve interpolation through the table;

[0025] The opposite phase potential and the main exciter loss of the main excitation machine under the action of different rotating speeds, electric angle positions, excitation currents and load resistances are calculated by the finite element method, and the calculated results are made into data tables of the opposite phase potential and the main excitation machine loss with respect to the main excitation machine under the action of different rotating speeds, electric angle positions, excitation currents and load side DC currents, and the corresponding opposite phase potential and loss of the main excitation machine under the action of any rotating speed, electric angle position, excitation current and load side DC current within the range of the data tables are obtained through spline curve interpolation of the data tables;

[0026] The opposite phase potential and the main excitation machine loss of the main excitation machine under the action of different rotating speeds, electric angle positions, excitation currents and load resistances are calculated by the finite element method, and the calculated results are made into data tables of the opposite phase potential and the main excitation machine loss with respect to the main excitation machine under the action of different rotating speeds, electric angle positions, excitation currents and load side DC currents, and the corresponding opposite phase potential and loss of the main excitation machine under the action of any rotating speed, electric angle position, excitation current and load side DC current within the range of the data tables are obtained through spline curve interpolation of the data tables.

[0027] Further, in step four, the characteristic calculation of the rectifier bridge is divided into three cases:

[0028] Case one: two or more of b11, b12 and b13 are equal to 0, then a1' and voltage c1' are 0;

[0029] Case two: two of b11, b12 and b13 are greater than 0;

[0030] For the case of b11 and b12>0, b13<0, the characteristic calculation process of the rectifier bridge is as follows:

[0031]

[0032] Wherein: i b11 and i b12 represent the phase currents of the opposite phase potential b11 and b12 branches respectively, V D (·) represents the volt-ampere characteristic curve of the diode, through which i b11 and i b12 are calculated, if both are greater than 0, then the secondary excitation machine rectified current a1'=(i b11 +i b12 ), and the voltage c1' = a1'Rs2; if there is a value less than 0 in i b11 and i b12 , it needs to be recalculated; if i b11 <0, the secondary excitation machine rectified current a1' = i b12 , and the voltage c1' = a1'Rs2; if ib12 <0, then The current a1' of the secondary exciter after rectification = i b11 The voltage c1' = a1'Rs2

[0033] For the case of b11 and b13 > 0, b12 < 0 and b12 and b13 > 0, b11 < 0, the calculation process of the characteristics of the rectifier bridge is the same as above.

[0034] Case three: one of b11, b12 and b13 is greater than 0.

[0035] For the case of b11 > 0, b12 and b13 < 0, the calculation process of the characteristics of the rectifier bridge is as follows:

[0036]

[0037] Wherein: i b13 represents the phase current of the opposite potential b13 branch, and i b12 and i b13 are calculated by the formula. b12 If i b13 and i b12 are both less than 0, then the current a1' of the secondary exciter after rectification = |(i b13 + i b12 )|, and the voltage c1' = a1'Rs2; if there is a value greater than 0 in i b13 and i b12 , then it needs to be recalculated. If i b13 > 0, then b13 If i b12 < 0, then

[0038] For the case of b12 > 0, b11 and b13 < 0 and b13 > 0, b11 and b12 < 0, the calculation process of the characteristics of the rectifier bridge is the same as above.

[0039] Further, step five is specifically: calculating the corresponding electrical angle position θ2 of the main exciter according to the electrical angle position θ1 of the secondary exciter;

[0040]

[0041] Wherein: p1 is the pole pair number of the secondary exciter, and p2 is the pole pair number of the main exciter.

[0042] Further, step seven is specifically: calculating the corresponding electrical angle position θ3 of the main generator according to the electrical angle position θ1 of the secondary exciter;​

[0043]

[0044] Wherein: p3 is the pole pair number of the main generator.

[0045] Further, in step nine, the loss of the three-stage generator system is calculated, specifically:

[0046] Taking the rotating speed of the three-stage generator system, the electric angle position θ1 of the auxiliary exciter and the load side current a1 of the auxiliary exciter as the base value, the corresponding loss in the auxiliary exciter loss data table is obtained through the spline interpolation method;

[0047] Taking the rotating speed of the three-stage generator system, the electric angle position θ2 of the main exciter, the rectified current a1' of the auxiliary exciter and the load side current a2 of the main exciter as the base value, the corresponding loss in the main exciter loss data table is obtained through the spline interpolation method;

[0048] Taking the rotating speed of the three-stage generator system, the electric angle position θ3 of the main generator, the rectified current a2' of the main exciter and the load side current a3 of the main generator as the base value, the corresponding loss in the main generator loss data table is obtained through the spline interpolation method;

[0049] The loss value P corresponding to the condition that the load side current of the auxiliary exciter is a1, the load side current of the main exciter is a2, the load side current of the main generator is a3, the resistance value of the stator winding of the auxiliary exciter is Rs1, the resistance value of the stator winding of the main exciter is Rs2, the resistance value of the stator winding of the main generator is Rs3, the resistance value of the rotor winding of the main exciter is Rr2 and the resistance value of the rotor winding of the main generator is Rr3 is calculated through the formula P=I 2 Rs, respectively.

[0050] Compared with the prior art, the beneficial effects of the present application are:

[0051] 1. Only a small amount of finite element data of the generator is needed to form the data table required for the performance calculation of the three-stage generator system, and the simulation of each unit of the three-stage generator system is independently performed, so that the time for evaluating the optimization of a component in the design stage through the method can be reduced.

[0052] 2. Based on the data samples calculated in advance, the performance under different working conditions can be quickly obtained through interpolation and iteration, which is more time-saving than the finite element method.

[0053] 3. The method outputs the direct current of the current stage of the three-stage generator as the input of the next stage, forming the current coupling of the whole front and rear stages. In addition, the losses of each stage are substituted into the thermal circuit calculation of the model, forming the overall temperature coupling. Compared with the traditional analysis of the performance indicators of each stage generator, it has more physical connection and can better meet the physical conditions of current and temperature coupling. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a flow chart of the three-stage generator system multi-field simplified external characteristic simulation modeling method of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0056] Specific embodiment one: as shown in the embodiment, a three-stage generator system multi-field simplified external characteristic simulation modeling method is disclosed, the method comprising the following steps: Figure 1

[0057] Step one: establish the opposite potential and loss data table of the three-stage generator system (provide basic data for simulation), the three-stage generator system including a sub-excitation machine, a main excitation machine and a main generator;

[0058] Step two: given the working condition of the three-stage generator system, including the main generator load side resistance, the environment temperature and the three-stage generator system speed (to simulate the actual operating environment);

[0059] Step three: set the initialization parameters; that is, set the initial values of the sub-excitation machine electrical angle position θ1, the sub-excitation machine load side current a1, the main excitation machine load side current a2 and the main generator load side current a3 to be 0 (to provide the starting point for simulation calculation);

[0060] Step four: taking the speed of the three-stage generator system, the electrical angle position θ1 of the sub-excitation machine and the load side current a1 of the sub-excitation machine as the base value, the corresponding opposite potential b11, b12 and b13 in the opposite potential data table of the sub-excitation machine are obtained by the spline interpolation method, according to the obtained opposite potential value, the stator winding value Rs1 of the sub-excitation machine under the current environment temperature and the stator winding value Rs2 of the main excitation machine under the current environment temperature, the rectified current a1' and voltage c1' of the sub-excitation machine are calculated according to the characteristics of the rectifier bridge;

[0061] Step five: calculate the corresponding electrical angle position θ2 of the main excitation machine;​

[0062] Step six: taking the rotational speed of the three-stage generator system, the electrical angle position of the main exciter θ2, the rectified current of the auxiliary exciter a1' and the load-side current of the main exciter a2 as the base values, the corresponding counter electromotive forces b21, b22 and b23 in the counter electromotive force data table of the main exciter are obtained by the spline interpolation method, the rectified current a2' and the voltage c2' of the main exciter are calculated according to the obtained counter electromotive force values, the rotor winding value Rr2 of the main exciter at the current ambient temperature and the rotor winding value Rr3 of the main generator at the current ambient temperature and the characteristics of the rectifier bridge; the calculation process is the same as that in step four;

[0063] Step seven: calculating the corresponding electrical angle position θ3 of the main generator;

[0064] Step eight: taking the rotational speed of the three-stage generator system, the electrical angle position of the main generator θ3, the rectified current of the main exciter a2' and the load-side current of the main generator a3 as the base values, the corresponding counter electromotive forces b31, b32 and b33 in the counter electromotive force data table of the main generator are obtained by the spline interpolation method, the rectified current a3' and the voltage c3' of the main generator are calculated according to the obtained counter electromotive force values, the stator winding value Rs3 of the main generator at the current ambient temperature and the load-side resistance value of the main generator and the characteristics of the rectifier bridge; the calculation process is the same as that in step six;

[0065] Step nine: calculating the loss of the three-stage generator system, and substituting the loss value P into the lumped thermal circuit equation of the three-stage generator system to obtain the winding temperature k of the three-stage generator system (the k values of the windings are different);

[0066] ΔT=QR Tij , Q=hA(T2-T1);

[0067] Wherein: Q is the heat of the thermal circuit, that is, the loss value P; ΔT is the temperature change of the thermal resistance; R Tij is the thermal resistance; h is the heat transfer coefficient; A is the heat transfer area; T2 is the temperature of the heat transfer surface; T1 is the ambient temperature;

[0068] And the resistance value Rij' of the winding at the temperature is calculated by the following formula, i=s, r; j=1, 2, 3; i=r and j=1 do not exist;

[0069]

[0070] The resistance values Rs1', Rs2', Rs3', Rr2' and Rr3' of the windings at the temperature are calculated by the formula, which are respectively the resistance values of Rs1, Rs2, Rs3, Rr2 and Rr3 at k degrees Celsius;

[0071] Step ten: difference between the initial resistance value Rij and the calculated Rij' is calculated, and it is determined whether it is less than δ, δ being a convergence error, which is a positive number approaching zero; if the difference is greater than the convergence error δ, the electrical angle position θ1 of the auxiliary exciter is updated (it can be increased by 1°), the aj' calculated above is used, j = 1, 2, 3 (a1', a2', a3' are the auxiliary exciter, main exciter, and main generator rectified currents calculated above), the DC side current aj is updated, j is a symbol, indicating j = 1, 2, 3 (i.e. a1 = a1', a2 = a2', a3 = a3', the values calculated in the last step are used as the initial values for the next calculation), the winding resistance Rij is updated using the winding resistance Rij' calculated above, and steps four to ten are re-executed until the convergence condition is met; if the difference is less than the convergence error δ, step eleven is continued;

[0072] Step eleven: the auxiliary exciter electrical angle position θ1 in the convergence state above is taken as 0° to 360°, the performance of the entire three-stage generator system is calculated, and the obtained data is output as the result, including the winding temperature of the three-stage generator system, the DC side current aj, the DC side voltage of the three-stage generator system, the loss of the three-stage generator system, and the load side power of the main generator.

[0073] Further, step one is specifically:

[0074] The counter electromotive force and the loss of the auxiliary exciter under the action of different speeds, electrical angle positions, and load resistances of the auxiliary exciter are calculated by the finite element method, and the calculated results are made into a data table of the counter electromotive force and the loss of the auxiliary exciter with respect to the auxiliary exciter under the action of different speeds, electrical angle positions, and load side DC currents, and the corresponding counter electromotive force and loss of the auxiliary exciter under any speed, electrical angle position, and DC side current within the range of the data table are obtained by spline curve interpolation of the data table;

[0075] The counter electromotive force and the loss of the main exciter under the action of different speeds, electrical angle positions, excitation currents, and load resistances of the main exciter are calculated by the finite element method, and the calculated results are made into a data table of the counter electromotive force and the loss of the main exciter with respect to the main exciter under the action of different speeds, electrical angle positions, excitation currents, and load side DC currents, and the corresponding counter electromotive force and loss of the main exciter under any speed, electrical angle position, excitation current, and load side DC current within the range of the data table are obtained by spline curve interpolation of the data table;

[0076] The phase reverse potential and the main generator loss of the main generator under the action of different rotating speeds, electric angle positions, excitation currents and load resistances are calculated by the finite element method, and the calculated results are made into data tables of the main generator phase reverse potential and the main generator loss with respect to the main generator under the action of different rotating speeds, electric angle positions, excitation currents and load side direct current, and the corresponding main generator phase reverse potential and loss under any rotating speed, electric angle position, excitation current and load side direct current within the range of the data table are obtained by spline curve interpolation of the data table.

[0077] Further, in step four, the characteristic calculation of the rectifier bridge is divided into three cases.

[0078] Case one: two or more of b11, b12 and b13 are equal to 0, then a1' and voltage c1' are 0;

[0079] Case two: two of b11, b12 and b13 are greater than 0;

[0080] For the case of b11 and b12>0, b13<0, the characteristic calculation process of the rectifier bridge is as follows:

[0081]

[0082] Wherein: i b11 and i b12 represent the phase currents of the reverse potential b11 and b12 branches respectively, V D (·) represents the volt-ampere characteristic curve of the diode, and i b11 and i b12 are calculated by the formula, if both are greater than 0, then the secondary exciter rectified current a1'=(i b11 +i b12 ), and the voltage c1' = a1'Rs2; if there is a value less than 0 in i b11 and i b12 , it needs to be recalculated; if i b11 <0, then the secondary exciter rectified current a1' = i b12 , and the voltage c1' = a1'Rs2; if i b12 <0, then the secondary exciter rectified current a1' = i b11 , and the voltage c1' = a1'Rs2;

[0083] For the case of b11 and b13>0, b12<0 and b12 and b13>0, b11<0, the characteristic calculation process of the rectifier bridge is the same as above.

[0084] Case three: one of b11, b12 and b13 is greater than 0;

[0085] For the case of b11>0, b12 and b13<0, the characteristic calculation process of the rectifier bridge is as follows:

[0086]

[0087] Wherein: i b13 represents the phase current of the opposite potential b13 branch, which is calculated by the formula b12 and i b13 If i b12 and i b13 are both less than 0, then the secondary exciter rectified current a1'= |(i b12 +i b13 )|, and the voltage is c1'=a1'Rs2; if there is a value greater than 0 in the calculation of i b12 and i b13 , then it needs to be recalculated; if i b12 >0, then the secondary exciter rectified current a1'= |i b13 |, and the voltage is c1'=a1'Rs2; if i b13 <0, then the secondary exciter rectified current a1'= |i b12 |, and the voltage is c1'=a1'Rs2;

[0088] For the case of b12>0, b11 and b13<0, and b13>0, b11 and b12<0, the characteristic calculation process of the rectifier bridge is the same as described above.

[0089] Further, step five is specifically: calculating the corresponding electrical angle position θ2 of the main exciter according to the electrical angle position θ1 of the secondary exciter;

[0090]

[0091] Wherein: p1 is the pole pair number of the secondary exciter, and p2 is the pole pair number of the main exciter.

[0092] Further, step seven is specifically: calculating the corresponding electrical angle position θ3 of the main generator according to the electrical angle position θ1 of the secondary exciter;

[0093]

[0094] Wherein: p3 is the pole pair number of the main generator.

[0095] Further, in step nine, the loss of the three-stage generator system is calculated, which is specifically:

[0096] The rotational speed of the three-stage generator system, the electric angle position of the auxiliary exciter θ1 and the load side current of the auxiliary exciter a1 are taken as the base values, and the corresponding loss in the auxiliary exciter loss data table is obtained through the spline interpolation method;

[0097] The rotational speed of the three-stage generator system, the electric angle position of the main exciter θ2, the rectified current of the auxiliary exciter a1' and the load side current of the main exciter a2 are taken as the base values, and the corresponding loss in the main exciter loss data table is obtained through the spline interpolation method;

[0098] The rotational speed of the three-stage generator system, the electric angle position of the main generator θ3, the rectified current of the main exciter a2' and the load side current of the main generator a3 are taken as the base values, and the corresponding loss in the main generator loss data table is obtained through the spline interpolation method;

[0099] The loss value P corresponding to the case that the load side current of the auxiliary exciter is a1, the load side current of the main exciter is a2, the load side current of the main generator is a3, the resistance of the stator winding of the auxiliary exciter is Rs1, the resistance of the stator winding of the main exciter is Rs2, the resistance of the stator winding of the main generator is Rs3, the resistance of the rotor winding of the main exciter is Rr2 and the resistance of the rotor winding of the main generator is Rr3 is calculated through the formula P=I 2 R.

[0100] The method of the application is used for simulating and analyzing the performance of the three-stage generator system under different working conditions, including the key parameters such as current, voltage, loss and temperature, so as to facilitate the design, optimization and fault diagnosis.

[0101] It is obvious for those skilled in the art that the application is not limited to the details of the above exemplary embodiments, and the application can be realized in other embodiments without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be included in the application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0102] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for simulating and modeling multi-field simplified external characteristics of a three-stage generator system, characterized by: The method comprises the following steps: Step 1: Create a reverse potential and loss data table for a three-stage generator system, which includes an auxiliary exciter, a main exciter, and a main generator. Step 2: Given the operating conditions of the three-stage generator system, including the load side resistance of the main generator, the ambient temperature, and the speed of the three-stage generator system; Step 3: Set initialization parameters; that is, set the initial values ​​of the auxiliary exciter electrical angle position θ1, the auxiliary exciter load side current a1, the main exciter load side current a2, and the main generator load side current a3 to 0; Step 4: Using the speed of the three-stage generator system, the electrical angle position θ1 of the auxiliary exciter, and the load-side current a1 of the auxiliary exciter as base values, the corresponding reverse EMFs b11, b12, and b13 in the reverse EMF data table of the auxiliary exciter are obtained by spline interpolation. Based on the obtained reverse EMF values, the stator winding value Rs1 of the auxiliary exciter at the current ambient temperature, and the stator winding value Rs2 of the main exciter at the current ambient temperature, the rectified current a1' and voltage c1' of the auxiliary exciter are calculated according to the characteristics of the rectifier bridge. Step 5: Calculate the electrical angle position θ2 corresponding to the main exciter; Step 6: Using the speed of the three-stage generator system, the electrical angle position θ2 of the main exciter, the rectified current a1' of the auxiliary exciter, and the load-side current a2 of the main exciter as base values, the corresponding reverse EMFs b21, b22, and b23 in the reverse EMF data table of the main exciter are obtained by spline interpolation. Based on the obtained reverse EMF values, the rotor winding value Rr2 at the current ambient temperature of the main exciter, and the rotor winding value Rr3 at the current ambient temperature of the main generator, the rectified current a2' and voltage c2' of the main exciter are calculated according to the characteristics of the rectifier bridge. The calculation process is the same as that of step 4. Step 7: Calculate the electrical angle position θ3 corresponding to the main generator; Step 8: Using the speed of the three-stage generator system, the electrical angle position θ3 of the main generator, the rectified current a2' of the main exciter, and the load-side current a3 of the main generator as base values, the corresponding reverse potentials b31, b32, and b33 in the reverse potential data table of the main generator are obtained by spline interpolation. Based on the obtained reverse potential values, the stator winding value Rs3 at the current ambient temperature of the generator, and the load-side resistance value of the main generator, the rectified current a3' and voltage c3' of the main generator are calculated according to the characteristics of the rectifier bridge; the calculation process is the same as that of step 6; Step 9: Calculate the loss of the three-stage generator system and substitute the above loss value P into the lumped thermal circuit equation of the three-stage generator system to calculate the temperature k of each winding of the three-stage motor system; ΔT=QR Tij ,Q=hA(T2-T1); Where: Q is the heat path heat, that is, the loss value P; ΔT is the temperature change of thermal resistance; R Tij is thermal resistance; h is heat transfer coefficient; A is heat transfer area; T2 is heat transfer surface temperature; T1 is ambient temperature; The resistance value Rij' of the winding at this temperature is calculated by the following formula, i = s, r; j = 1, 2, 3; if i = r and j = 1 does not exist; The resistance values ​​of the windings at this temperature are calculated using this formula. Rs1', Rs2', Rs3', Rr2', and Rr3' are the resistance values ​​of Rs1, Rs2, Rs3, Rr2, and Rr3 at k degrees Celsius respectively; Step 10: Subtract the initial resistance value Rij from the Rij' calculated above and determine whether it is less than δ, where δ is the convergence error and is a positive number approaching zero. If the difference is greater than the convergence error δ, then update the electrical angle position θ1 of the auxiliary exciter, and use the aj' calculated above, j = 1, 2, 3, to update the DC side current aj, where j is a symbol indicating j = 1, 2, 3. Use the winding resistance Rij' calculated above to update the winding resistance Rij, and re-execute steps 4 to 10 until the convergence condition is met. If the difference is less than the convergence error δ, then continue with step 11. Step 11: The electrical angle position θ1 of the auxiliary exciter in the above convergence state is set to 0° to 360°, and the performance of the entire three-stage generator system is calculated. The obtained data is output as the result, including the winding temperature of the three-stage generator system, the DC side current aj of the three-stage generator system, the DC side voltage of the three-stage generator system, the loss of the three-stage generator system, and the load side power of the main generator.

2. The multi-field simplified external characteristic simulation modeling method for a three-stage generator system according to claim 1, characterized in that: Step 1 is as follows: The reverse electromotive force and loss of the auxiliary exciter under different speeds, electrical angle positions and load resistances of the auxiliary exciter are calculated by the finite element method, and the calculated results are made into a data table of the reverse electromotive force and loss of the auxiliary exciter under different speeds, electrical angle positions and load-side DC currents of the auxiliary exciter. The reverse electromotive force and loss of the auxiliary exciter corresponding to any speed, electrical angle position and DC-side current within the range of the data table are obtained by spline curve interpolation through the table; Calculating the reverse electromotive force and the loss of the main exciter under different speeds, electrical angle positions, excitation currents, and load resistances of the main exciter by the finite element method, and making the calculated results into a data table of the reverse electromotive force and the loss of the main exciter under different speeds, electrical angle positions, excitation currents, and load-side DC currents of the main exciter, respectively. Spline curve interpolation is performed on the data table to obtain the corresponding reverse electromotive force and loss of the main exciter under any speed, electrical angle position, excitation current, and load-side DC current within the range of the data table; The finite element method is used to calculate the reverse electromotive force and main generator loss of the main generator under different speeds, electrical angle positions, excitation currents and load resistances, and the calculated results are made into data tables of the reverse electromotive force and main generator loss of the main generator under different speeds, electrical angle positions, excitation currents and load-side DC currents. Spline curve interpolation is performed on the data tables to obtain the corresponding reverse electromotive force and loss of the main generator under any speed, electrical angle position, excitation current and load-side DC current within the range of the data table.

3. The multi-field simplified external characteristic simulation modeling method for a three-stage generator system according to claim 1, characterized in that: In step 4, the characteristic calculation of the rectifier bridge is divided into three cases: Case 1: If two or more of b11, b12, and b13 are equal to 0, then a1' and voltage c1' are 0; Case 2: Two of b11, b12, and b13 are greater than 0; For b11 and b12>0, b13<0, the characteristic calculation process of the rectifier bridge is as follows: Where: i b11 and i b12 Represents the phase current of the opposite potential b11 and b12 branches, V D (·) represents the volt-ampere characteristic curve of the diode, and i is calculated by this formula. b11 and i b12 If both are greater than 0, the auxiliary exciter rectified current a1'=(i b11 +i b12 ), voltage c1'=a1'Rs2; if the calculated i b11 and i b12 If there is a value less than 0 in i, it needs to be recalculated; if i b11 <0, then i b11 =0, The auxiliary exciter rectified current a1'=i b12 , voltage c1'=a1'Rs2; if i b12 <0, then i b12 =0, the auxiliary exciter rectified current a1'=i b11 , voltage c1'=a1'Rs2; For the cases where b11 and b13>0, b12<0 and b12 and b13>0, b11<0, the characteristic calculation process of the rectifier bridge is the same as above; Case 3: One of b11, b12 and b13 is greater than 0; For b11>0, b12 and b13<0, the characteristic calculation process of the rectifier bridge is as follows: Where: i b13 Represents the phase current of the opposite potential b13 branch, and the i is calculated by this formula b12 and i b13 , if i b12 and i b13 are all less than 0, then the auxiliary exciter rectifier current a1'=|(i b12 +i b13 )|, the voltage is c1'=a1'Rs2; if the calculated i b12 and i b13 If there is a value greater than 0 in i, it needs to be recalculated; if i b12 >0, then i b12 =0, The auxiliary exciter rectified current a1'=|i b13 |, the voltage is c1'=a1'Rs2; if i b13 <0, then i b13 =0, auxiliary exciter rectified current a1'=|i b12 |, the voltage is c1'=a1'Rs2; For the cases of b12>0, b11 and b13<0 and b13>0, b11 and b12<0, the characteristic calculation process of the rectifier bridge is the same as above.

4. The multi-field simplified external characteristic simulation modeling method for a three-stage generator system according to claim 1, characterized in that: Step 5 is specifically as follows: calculating the corresponding electrical angle position θ2 of the main exciter according to the electrical angle position θ1 of the auxiliary exciter; Where: p1 is the pole pair number of the auxiliary exciter, and p2 is the pole pair number of the main exciter.

5. The multi-field simplified external characteristic simulation modeling method for a three-stage generator system according to claim 1, characterized in that: Step seven is specifically as follows: calculating the electrical angle position θ3 corresponding to the main generator according to the electrical angle position θ1 of the auxiliary exciter; Among them: p3 is the number of pole pairs of the main generator.

6. The multi-field simplified external characteristic simulation modeling method for a three-stage generator system according to claim 1, characterized in that: In step nine, the losses of the three-stage generator system are calculated as follows: Using the speed of the three-stage generator system, the electrical angle position θ1 of the auxiliary exciter, and the load-side current a1 of the auxiliary exciter as base values, the corresponding losses in the auxiliary exciter loss data table are obtained using the spline interpolation method. Using the speed of the three-stage generator system, the electrical angle position θ2 of the main exciter, the rectified current a1' of the auxiliary exciter, and the load-side current a2 of the main exciter as base values, the corresponding losses in the main exciter loss data table are obtained using the spline interpolation method. Using the speed of the three-stage generator system, the main generator electrical angle position θ3, the main exciter rectified current a2', and the main generator load side current a3 as base values, the corresponding losses in the main generator loss data table are obtained using the spline interpolation method; Through the formula P=I 2 R, calculate the corresponding loss value P when the auxiliary exciter load side current is a1, the main exciter load side current is a2, the main generator load side current is a3, the auxiliary exciter stator winding resistance is Rs1, the main exciter stator winding resistance is Rs2, the main generator stator winding resistance is Rs3, the main exciter rotor winding resistance is Rr2, and the main generator rotor winding resistance is Rr3.

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