Transmission scheme simulation method of planetary variable-frequency speed regulation device

Abstract

A transmission scheme simulation method of a planetary variable-frequency speed regulation device belongs to the technical field of power generation, and aims to solve the problem of equipment operation failure caused by lack of an operation simulation method and complex field operation condition of the planetary variable-frequency speed regulation device, and comprises the following steps: collecting operation data of an actual working condition point of a feed pump for curve fitting to obtain a working condition curve of a planetary gearbox; selecting a main motor, and acquiring power and rotating speed data of the main motor; a to-be-simulated mechanical transmission scheme is set, the speed ratio from an auxiliary motor to a planet carrier and the speed ratio from the planet carrier to a sun gear are obtained, and then the rotating speed and torque of the auxiliary motor are obtained; setting a working mode of the planetary variable-frequency speed regulation device to be simulated, and obtaining power and rotating speed data of an auxiliary motor; and fitting the rotating speed, the torque, the rotating speed and the power of the auxiliary motor to obtain a working condition curve of the auxiliary motor, judging whether the working condition curve accords with a theoretical value or not, and otherwise, modifying the mechanical transmission scheme and the working mode of the planetary variable-frequency speed regulation device until the working condition curve of the auxiliary motor accords with the theoretical value. The device is used for high-power speed regulation of the feed pump.

Description

Technical Field

[0001] The invention relates to a transmission scheme simulation method for a planetary variable frequency speed regulating device, and belongs to the technical field of power generation. Background Art

[0002] The planetary frequency conversion speed regulation device is a high-power speed regulation device that controls the feed water pump in the thermal power generation field. It is the main component for the normal operation of the power plant. It is based on the principles of planetary differential speed regulation and power diversion. It is mainly composed of a frequency converter, a planetary gearbox and an auxiliary motor. When the power plant is operating at low load, part of the power input by the main motor can be fed to the power grid. Compared with the traditional hydraulic coupling that can only regulate speed but not feed power, the efficiency is greatly improved.

[0003] At present, with the development of new energy sources such as photovoltaic and wind power, the field of thermal power generation has been gradually squeezed, the probability of power plants operating at low loads has gradually increased, and the power consumption rate of feedwater pumps in thermal power plants has remained high, which directly affects the economic and technical indicators and energy-saving benefits of the entire plant. Therefore, planetary frequency conversion speed regulation devices have good application prospects. However, since the planetary frequency conversion device is a mechatronic device, coupled with the variable on-site operating conditions, different conventional operating loads of power plants in different regions, different feedwater pump capacities, different water supply logics and other influencing factors, even the same equipment will have different problems at different sites due to on-site operating factors, resulting in time and economic losses for the owner. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that a planetary frequency conversion device lacks an operation simulation method, the on-site operation conditions are complex, and equipment operation failures occur. A transmission scheme simulation method for a planetary frequency conversion speed regulation device is provided.

[0005] The transmission scheme simulation method of a planetary variable frequency speed regulating device described in the present invention comprises:

[0006] S1. Collect the actual operating data of the feedwater pump of the power plant, perform curve fitting, and obtain the operating curve of the feedwater pump, which is the operating curve of the planetary gearbox; select the main motor and obtain the power and speed data of the main motor;

[0007] S2. Set the mechanical transmission scheme to be simulated, obtain the speed ratio from the auxiliary motor to the planet carrier, and the speed ratio from the planet carrier to the sun gear, and then obtain the speed and torque of the auxiliary motor;

[0008] S3, setting the working mode of the planetary variable frequency speed regulating device to be simulated, and obtaining the power and speed data of the auxiliary motor according to the working mode and the power and speed data of the active motor;

[0009] S4, fitting the speed and torque of the auxiliary motor obtained in S2 and the speed and power of the auxiliary motor obtained in S3 to obtain a working condition curve of the auxiliary motor;

[0010] S5. Determine whether the auxiliary motor operating curve obtained in S4 conforms to the theoretical value. Otherwise, modify the mechanical transmission scheme and the working mode of the planetary variable frequency speed regulation device until the auxiliary motor operating curve conforms to the theoretical value.

[0011] Preferably, the actual operating point operation data of the water supply pump in S1 includes: water supply pressure, flow rate, speed, water pump current and generator power.

[0012] Preferably, the operating curve of the planetary gearbox in S1 includes: a torque curve and a power curve;

[0013] The torque curve has the rotation speed as the horizontal coordinate and the torque as the vertical coordinate;

[0014] The power curve has the rotation speed as the horizontal coordinate and the power as the vertical coordinate.

[0015] Preferably, the operating condition curve is fitted using the cftool module in Matlab, and the R-Square of the fitting curve is greater than 0.9.

[0016] Preferably, the working modes of the planetary variable frequency speed regulating device include: low load power feeding condition and high load power generation condition;

[0017] The low-load power feeding condition corresponds to the forward rotation of the auxiliary motor, and the high-load power generation condition corresponds to the reverse rotation of the auxiliary motor.

[0018] Preferably, the main motor is drivingly connected to the outer ring gear of the planetary gearbox, and the auxiliary motor is drivingly connected to the planet carrier of the planetary gearbox.

[0019] Advantages of the present invention: The transmission scheme simulation method of a planetary frequency conversion speed regulation device described in the present invention can solve the problem that failures of some links of the planetary frequency conversion speed regulation device are difficult to detect due to the complexity of the mechatronics system, and provides a simulation method for establishing a simulation in matlab / simulink. By inputting parameters such as load, auxiliary motor power, and speed, the actual operating conditions of the equipment are simulated, the weak points of the equipment during operation are analyzed, and the risk points are found in advance. The feasibility of the planetary frequency conversion speed regulation device is verified in the scheme design stage, so that when the scheme is formulated, possible problems can be solved from the perspective of the mechanical structure or the electrical part, thereby further saving time and economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a principle block diagram of the transmission scheme simulation method of the planetary variable frequency speed regulating device of the present invention;

[0021] Figure 2 It is a schematic diagram of the output result curve of the auxiliary motor output current changing with the output load. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0025] Embodiment 1:

[0026] Combine the following Figure 1 The present embodiment is described. The transmission scheme simulation method of a planetary variable frequency speed regulating device described in the present embodiment comprises:

[0027] S1. Collect the actual operating data of the feedwater pump of the power plant, perform curve fitting, and obtain the operating curve of the feedwater pump, which is the operating curve of the planetary gearbox; select the main motor and obtain the power and speed data of the main motor;

[0028] S2. Set the mechanical transmission scheme to be simulated, obtain the speed ratio from the auxiliary motor to the planet carrier, and the speed ratio from the planet carrier to the sun gear, and then obtain the speed and torque of the auxiliary motor;

[0029] S3, setting the working mode of the planetary variable frequency speed regulating device to be simulated, and obtaining the power and speed data of the auxiliary motor according to the working mode and the power and speed data of the active motor;

[0030] S4, fitting the speed and torque of the auxiliary motor obtained in S2 and the speed and power of the auxiliary motor obtained in S3 to obtain a working condition curve of the auxiliary motor;

[0031] S5. Determine whether the auxiliary motor operating curve obtained in S4 conforms to the theoretical value. Otherwise, modify the mechanical transmission scheme and the working mode of the planetary variable frequency speed regulation device until the auxiliary motor operating curve conforms to the theoretical value.

[0032] Furthermore, the actual operating point operation data of the water supply pump described in S1 includes: water supply pressure, flow rate, speed, water pump current and generator power.

[0033] Furthermore, the operating curve of the planetary gearbox described in S1 includes: a torque curve and a power curve;

[0034] The torque curve has the rotation speed as the horizontal coordinate and the torque as the vertical coordinate;

[0035] The power curve has the rotation speed as the horizontal coordinate and the power as the vertical coordinate.

[0036] Furthermore, the operating curve is fitted using the cftool module in Matlab, and the R-Square of the fitting curve is greater than 0.9.

[0037] Furthermore, the working modes of the planetary variable frequency speed regulating device include: low load power feeding condition and high load power generation condition;

[0038] The low-load power feeding condition corresponds to the forward rotation of the auxiliary motor, and the high-load power generation condition corresponds to the reverse rotation of the auxiliary motor.

[0039] Furthermore, the main motor is drivingly connected to the outer gear ring of the planetary gearbox, and the auxiliary motor is drivingly connected to the planet carrier of the planetary gearbox.

[0040] In the present invention, the operation data of the power plant feedwater pump is collected, and the curve fitting is performed through the cftool module in matllab, and finally the working curve of the planetary frequency conversion device is obtained, and the fitting result R-Square should be greater than 0.9. The operation data of the on-site feedwater pump is collected, including data such as feedwater pressure, flow, speed, pump current, generator power, etc. The working point of the planetary frequency conversion device is calculated, and according to the distribution, the polynomial fitting in the cftool module is used to judge the fitting effect according to the R-SQUARE, SSE, and RMSE in the fitting results.

[0041] In the present invention, the auxiliary motor module is established by setting the PMSM module. The auxiliary motor has two directions of rotation, positive and negative, corresponding to the two working modes of the planetary frequency converter. The main motor module is established by using the synchronous Machine. The speed and power of the main motor are given values ​​and do not change with the load. Basic parameters are given, including speed, power, rotation direction, etc. The auxiliary motor module is established by using the PMSM in the simulink library. According to the motor data in the overall system, the resistance value, inertia moment, speed, rotation direction, etc. are given. The main motor module is established by using the synchronous Machine, and the main motor working curve is selected according to the main motor type.

[0042] In the present invention, according to the mechanical transmission scheme of the planetary variable frequency speed regulation device, the speed ratio of the planetary gearbox is determined, and the speed ratio is combined with the corresponding speed. The output speed of the planetary gear is calculated and synthesized by the speed of the main motor and the speed of the auxiliary motor. The auxiliary motor is connected to the planetary carrier through an idler gear. The speed ratio from the planetary carrier to the auxiliary motor and the speed ratio from the planetary carrier to the sun gear need to be given. The input and output speeds are r / min. In the planetary variable frequency speed regulation scheme, the main motor is connected to the outer gear ring, and the auxiliary motor is connected to the planetary carrier. When the module is established, the number of sun gear teeth, the number of outer gear ring teeth, the number of planetary gear teeth, and the speed ratio from the planetary carrier to the auxiliary motor need to be given according to the mechanical transmission scheme. The speed of the main motor and the speed of the auxiliary motor are associated with the corresponding speed ratio.

[0043] In the present invention, the load in the working curve is imported into Simulink, and the output current change trend of the auxiliary motor is obtained through the bus selector module, and compared with the rated current of the auxiliary motor. Considering the quick-break protection of the auxiliary motor, the final current to be compared should be the rated current of the auxiliary motor multiplied by the motor quick-break protection coefficient. The bus selector module is connected to the output interface of the auxiliary motor module to obtain the waveforms of the three-phase current, speed, torque, etc. of the auxiliary motor, such as Figure 2 As shown, according to the motor model, the auxiliary motor quick-break protection coefficient and the motor rated current are confirmed, and the two are multiplied to obtain the theoretical maximum value of the auxiliary motor. The working curve of the planetary frequency conversion device obtained by fitting is used to obtain the current amplitude of the comparative output result under different loads, which is compared with the theoretical maximum value of the auxiliary motor to judge the rationality of the solution and the direction of improvement.

[0044] In the present invention, the working point of the water pump is obtained, and the working curve of the planetary frequency converter is obtained by fitting. The main motor module is established to confirm the power and speed of the main motor. According to the working mode of the planetary frequency converter, the power, speed, and rotation direction of the auxiliary motor are given, and the working efficiency of the inverter is given. According to the mechanical transmission scheme, the speed ratio of the auxiliary motor to the planet carrier of the planetary gearbox and the speed ratio of the planet carrier to the sun gear are given. According to the working curve, the current and torque change trend of the auxiliary motor are obtained by fitting.

[0045] In the present invention, the rotation speed of the planetary gearbox is a synthesis of the rotation speeds of the main motor and the auxiliary motor. At least the auxiliary motor to planet carrier speed ratio and the planet carrier to sun gear speed ratio must be given. It is determined whether to add a parallel stage on the output side of the planetary gearbox according to needs.

[0046] In the present invention, the power and rotation speed of the main motor are fixed values.

[0047] In the present invention, the power and speed of the auxiliary motor need to be given manually, and the auxiliary motor can rotate in both directions.

[0048] In the present invention, there are two types of analysis results, one is that the output load remains unchanged and the auxiliary motor power is modified, and the other is that the auxiliary motor power remains unchanged and the load is modified.

[0049] In the present invention, firstly, the operation data of the on-site water pump is obtained, and the curve fitting is performed according to the operation data to obtain the working curve of the planetary frequency conversion device; secondly, the main motor method is established, the power speed is given, the planetary stage speed ratio and the parallel stage speed ratio are given according to the mechanical scheme, and the auxiliary motor speed, power and rotation direction are given according to the working mode of the planetary frequency conversion device. Through the fitted working curve, the current and torque change trends of the auxiliary motor at different working points are calculated, so as to judge the rationality of the existing scheme.

[0050] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A transmission scheme simulation method for a planetary variable frequency speed regulating device, characterized in that: It includes: S1. Collect the actual operating data of the feedwater pump of the power plant, perform curve fitting, and obtain the operating curve of the feedwater pump, which is the operating curve of the planetary gearbox; select the main motor and obtain the power and speed data of the main motor; S2. Set the mechanical transmission scheme to be simulated, obtain the speed ratio from the auxiliary motor to the planet carrier, and the speed ratio from the planet carrier to the sun gear, and then obtain the speed and torque of the auxiliary motor; S3, setting the working mode of the planetary variable frequency speed regulating device to be simulated, and obtaining the power and speed data of the auxiliary motor according to the working mode and the power and speed data of the active motor; S4, fitting the speed and torque of the auxiliary motor obtained in S2 and the speed and power of the auxiliary motor obtained in S3 to obtain a working condition curve of the auxiliary motor; S5. Determine whether the auxiliary motor operating curve obtained in S4 conforms to the theoretical value. Otherwise, modify the mechanical transmission scheme and the working mode of the planetary variable frequency speed regulation device until the auxiliary motor operating curve conforms to the theoretical value.

2. The transmission scheme simulation method of a planetary variable frequency speed regulating device according to claim 1 is characterized in that: The actual operating point operation data of the water supply pump described in S1 include: water supply pressure, flow rate, speed, water pump current and generator power.

3. The transmission scheme simulation method of a planetary variable frequency speed regulating device according to claim 1, characterized in that: The operating curves of the planetary gearbox described in S1 include: a torque curve and a power curve; The torque curve has the rotation speed as the horizontal coordinate and the torque as the vertical coordinate; The power curve has the rotation speed as the horizontal coordinate and the power as the vertical coordinate.

4. The transmission scheme simulation method of a planetary variable frequency speed regulating device according to claim 1 is characterized in that: The operating curve is fitted using the cftool module in Matlab, and the R-Square of the fitting curve is greater than 0.

9.

5. The transmission scheme simulation method of a planetary variable frequency speed regulating device according to claim 1 is characterized in that: The working modes of the planetary variable frequency speed regulating device include: low load feeding condition and high load power generation condition; The low-load power feeding condition corresponds to the forward rotation of the auxiliary motor, and the high-load power generation condition corresponds to the reverse rotation of the auxiliary motor.

6. A transmission scheme simulation method for a planetary variable frequency speed regulating device according to any one of claims 1 to 5, characterized in that: The main motor is drivingly connected to the outer gear ring of the planetary gear box, and the auxiliary motor is drivingly connected to the planet carrier of the planetary gear box.

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