Matlab / Simulink-based deep sea underwater equipment alternating current power supply system and simulation method

Abstract

The invention discloses a deep sea underwater equipment alternating current power supply system and a simulation method based on Matlab / Simulink, and the method comprises the steps: carrying out the modeling of each important part of the deep sea underwater equipment alternating current power supply system, and building a whole power supply system simulation model according to the simulation parameters of the system; a mother ship power supply emits preset alternating current, and the voltage is boosted to a target voltage value through a boosting device; electric energy is transmitted through an umbilical cable, one path supplies power to the underwater high-voltage motor, and the other path is reduced to a preset voltage value through a step-down transformer; the alternating current with the preset voltage value is converted into direct current with the preset voltage value through rectification of a rectifier; by collecting simulation waveforms of key parts of a power generation side, a high-voltage side, a motor side and a direct-current low-voltage side in a power supply system, the running condition of the whole power supply system and the reasonability of the design of the power supply system are judged, parameters of power supply equipment are changed in real time, the parameters are optimized through the simulation waveforms, and simulation of the power supply system is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of design and verification of a deep-sea underwater equipment power supply system, and in particular relates to a deep-sea underwater equipment AC power supply system and a simulation method based on Matlab / Simulink. Background Art

[0002] With the reduction of onshore resources, deep-sea resources have been increasingly accepted as an important alternative to terrestrial resources. In recent years, deep-sea underwater equipment technology has developed rapidly, and the exploitation of deep-sea resources has also been accelerated. Through deep-sea exploration, sampling and other means, accurate and comprehensive seabed data and samples can be obtained, providing a scientific basis for resource exploration and development, which is of irreplaceable significance for the exploration and development of seabed resources. The main deep-sea underwater exploration equipment includes: deep-sea drilling rigs, underwater robots, submersibles, etc. These equipment integrate power, communication, control, drilling and other functions together, with high integration and complexity, and must be able to withstand extremely high water pressure and harsh environmental conditions.

[0003] These deep-sea underwater equipment are in extreme deep-sea environments, and the power supply system (PSS) is the key to ensuring the normal operation of the equipment and the effective and long-term execution of tasks. The PSS of deep-sea underwater equipment usually includes several aspects such as energy source, energy transmission, energy conversion, and load. At present, the more mature power supply scheme for deep-sea underwater equipment is that the mother ship power generation system transmits power to the underwater equipment through an umbilical cable. The umbilical cable is generally an armored composite cable that integrates power transmission and communication functions, and its length can reach thousands of meters. The PSS that uses the umbilical cable to transmit power is divided into two transmission modes: DC transmission and three-phase AC transmission. Because most of the motors of deep-sea underwater equipment use high-power oil-immersed AC motors, the three-phase AC transmission mode has the advantages of being able to directly use transformers for power conversion, simple system structure, and low cost, so the design and verification of AC PSS is analyzed in detail.

[0004] The AC power supply system of deep-sea underwater equipment includes power generation, transmission, transformation, distribution and other processes, and includes a variety of loads with different powers. It is an extremely complex system. According to the working water depth of the equipment operation system, the power source and load operation requirements, different specifications of power supplies, transformers, umbilical cables, power converters and other devices are matched, and then the overall power supply system is designed, and the design scheme is verified and optimized using MATLAB / Simulink tools. Based on MATLAB / Simulink tools, a simulation method for the design scheme of AC power supply system of deep-sea underwater equipment is provided to solve the system parameter selection and parameter optimization design problems under the mutual constraints of multiple factors. Summary of the invention

[0005] To solve the above technical problems, the present invention proposes an AC power supply system and simulation method for deep-sea underwater equipment based on Matlab / Simulink to improve system design efficiency, enhance system reliability, optimize operation and performance, and support control strategy development.

[0006] On the one hand, to achieve the above-mentioned purpose, the present invention provides a deep-sea underwater equipment AC power supply system based on Matlab / Simulink, comprising:

[0007] Mother ship power supply, water ascent device, umbilical cable, underwater high-voltage motor, underwater step-down device, converter, hydraulic system and low-voltage DC load;

[0008] The mother ship power supply is used to provide three-phase alternating current to the power supply system;

[0009] The underwater boosting device, which is composed of a low-voltage voltage regulator and an isolation boosting transformer, is used to receive the alternating current from the mother ship power supply and regulate the electric energy, and transmit the regulated electric energy to the umbilical cable;

[0010] The umbilical cable is used to transmit electrical energy to the seabed. After the electrical energy reaches the seabed, one path directly supplies power to the underwater high-voltage motor to drive the hydraulic pump and provide energy for the underwater hydraulic system; the other path passes through the underwater pressure reducing device, and after voltage reduction and rectification, it supplies power to other low-voltage electrical loads of the underwater equipment.

[0011] Optionally, the water boost device includes a low voltage regulator and an isolation boost transformer;

[0012] The low voltage regulator is used to ensure that the output voltage remains stable when the input voltage varies within a certain range;

[0013] The isolation step-up transformer is used to increase the stable voltage output by the voltage regulator to a required voltage level and to electrically isolate the input end from the output end.

[0014] Optionally, a π-shaped equivalent circuit model is constructed based on the characteristic parameters of the umbilical cable, and the π-shaped equivalent circuit model is converted into an impedance model, which is expressed as:

[0015]

[0016] Where Z is the line impedance and inductance, Y is the circuit capacitive reactance, r 1 is the resistance per unit length of cable, l is the length of the umbilical cable, x 1 is the inductance of the cable per unit length, f is the power frequency, L 1 is the inductance per unit length of the cable, b 1 is the capacitance per unit length of the cable.

[0017] Optionally, obtaining the voltage and current at the head end of the umbilical cable based on the π-shaped equivalent circuit model includes:

[0018]

[0019] Converted into matrix form:

[0020]

[0021] Among them, U 1 is the voltage at the head end of the umbilical cable, I 1 is the umbilical cable current.

[0022] Optionally, starting the underwater high-voltage motor requires calculating the rated torque of the motor, the output power of the pump driven by the motor, the input power of the pump, the starting torque required to drive the pump group, and the electromagnetic torque of the motor.

[0023] The rated torque of the motor is calculated as follows:

[0024]

[0025] Among them, T is the electromagnetic torque of the motor; P is the motor power; n is the motor speed;

[0026] The output power of the pump driven by the motor is calculated as follows:

[0027] P out =p s ×D m ×ω,

[0028] Among them, D m is the maximum displacement of the pump, ω is the speed, p s To start the working pressure;

[0029] The input power of the pump is calculated as follows:

[0030]

[0031] Where η is the efficiency of the pump;

[0032] The starting torque required to drive the pump group is calculated as follows:

[0033]

[0034] Among them, n N is the rated speed;

[0035] The calculation of the motor electromagnetic torque is as follows:

[0036]

[0037] Among them, U 1is the voltage of the stator winding; f 1 is the AC frequency; s is the slip rate; m 1 ,p,R 1 ,X 1 ,R′ 2 , X′ 2 are the specific parameters of the motor respectively.

[0038] Optionally, the converter device converts low-voltage AC power into DC power to power controllers, communication devices, monitoring and lighting equipment.

[0039] Optionally, a DC load equivalent model is established to equate the DC load to a constant power load under closed-loop control.

[0040] On the other hand, to achieve the above purpose, the present invention also provides a simulation method for an AC power supply system of deep-sea underwater equipment based on Matlab / Simulink, comprising:

[0041] Model the important components of the AC power supply system of deep-sea underwater equipment, and establish a simulation model of the entire power supply system based on the simulation parameters of the system;

[0042] The mother ship power source generates a preset alternating current, and the voltage is increased to the target voltage value by the booster device;

[0043] The electric energy is transmitted through the umbilical cable, one way is to supply power to the underwater high-voltage motor, and the other way is stepped down to a preset voltage value by a step-down transformer;

[0044] The alternating current with a preset voltage value is converted into direct current with a preset voltage value by rectifying with a rectifier;

[0045] By collecting simulation waveforms of key parts of the power supply system, including the generation side, high voltage side, motor side, and DC low voltage side, the operating status of the entire power supply system and the rationality of the power supply system design can be judged, the parameters of the power supply equipment can be changed in real time, and the parameters can be optimized through simulation waveforms to complete the simulation of the power supply system.

[0046] Technical effect of the invention: The invention discloses an AC power supply system and simulation method for deep-sea underwater equipment based on Matlab / Simulink, introduces the overall structural framework and working principle of the AC power supply system for deep-sea underwater equipment; analyzes the system's booster device, umbilical cable model, underwater high-voltage motor starting method, and constant power load equivalent model; and improves system design efficiency, enhances system reliability, optimizes operation and performance, and supports control strategy development by simulating and analyzing the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0048] Figure 1 This is a schematic diagram of the structure of an AC power supply system for deep-sea underwater equipment based on Matlab / Simulink according to an embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of the overall design of the AC power supply system according to an embodiment of the present invention;

[0050] Figure 3 This is a schematic diagram of a voltage increase / decrease device according to an embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of a voltage regulator according to an embodiment of the present invention;

[0052] Figure 5 This is a transformer principle diagram of an embodiment of the present invention;

[0053] Figure 6 This is a structural diagram of a hybrid energy storage model predictive control method according to an embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of capacitor current control voltage according to an embodiment of the present invention;

[0055] Figure 8 A typical RC low-pass filter circuit according to an embodiment of the present invention;

[0056] Fig. 9 A schematic diagram of a topological structure of a three-phase PWM rectifier according to an embodiment of the present invention;

[0057] Fig.10 This is a schematic diagram of the control principle of a three-phase PWM rectifier according to an embodiment of the present invention;

[0058] Fig.11 This is a schematic diagram of the control principle of the backup battery and its DC-DC converter according to an embodiment of the present invention;

[0059] Fig.12 This is a schematic diagram of a constant power load equivalent model according to an embodiment of the present invention;

[0060] Fig.13 It is a simulation model of the power supply system of an embodiment of the present invention, wherein (a) is the main circuit, (b) is the three-phase power supply module, (c) is the umbilical cable transmission π-type equivalent model subsystem, (d) is the three-phase rectifier module, (e) is the three-phase rectifier control module, (f) is the constant power load module, and (g) is the backup battery and its control module;

[0061] Fig.14A schematic diagram of voltage and current waveforms of a three-phase AC source according to an embodiment of the present invention;

[0062] Fig.15 A schematic diagram of voltage and current waveforms on the high-voltage side of an embodiment of the present invention;

[0063] Fig.16 Schematic diagram of the rotor and stator current, speed, and torque waveforms of the three-phase asynchronous motor according to an embodiment of the present invention;

[0064] Fig.17 Schematic diagram of the voltage waveform of the low-voltage DC side according to an embodiment of the present invention. DETAILED DESCRIPTION

[0065] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0066] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0067] like Figure 1 As shown, in this embodiment, a deep-sea underwater equipment AC power supply system based on Matlab / Simulink is provided, including: a bus power supply, a water rising device, an umbilical cable, an underwater high-voltage motor, an underwater voltage reduction device, a converter, a hydraulic system and a low-voltage DC load;

[0068] The mother ship power supply is used to provide three-phase alternating current to the power supply system;

[0069] The underwater boosting device, which is composed of a low-voltage voltage regulator and an isolation boosting transformer, is used to receive the alternating current from the mother ship power supply and regulate the electric energy, and transmit the regulated electric energy to the umbilical cable;

[0070] The umbilical cable is used to transmit electrical energy to the seabed. After the electrical energy reaches the seabed, one path directly supplies power to the underwater high-voltage motor to drive the hydraulic pump and provide energy for the underwater hydraulic system; the other path passes through the underwater pressure reducing device and supplies power to other low-voltage electrical loads of the underwater equipment after the pressure is reduced.

[0071] The converter device mainly includes a rectifier and a DC converter, wherein the rectifier is used to convert AC power into DC power, and the DC converter is used to charge and discharge the backup battery;

[0072] Specifically, the AC power supply system for deep-sea underwater equipment mainly includes energy source, energy transmission, energy conversion, and load. The energy source mainly includes the mother ship power generation system and electrochemical energy. Energy transmission refers to the energy transmission process from the energy source to the underwater equipment. Energy conversion refers to the high-low voltage conversion and AC / DC conversion of electric energy. Load refers to the power load of underwater equipment. The overall structural framework of the AC power supply system transmitted through the umbilical cable is as follows: Figure 1 As shown in the figure, it is mainly composed of mother ship power supply, step-up / step-down transformer, umbilical cable, underwater high-voltage motor, power converter, hydraulic system, etc. The working principle of the power supply system is as follows: the mother ship power supply is usually 380V / 50Hz or 690V / 50Hz or 440V / 60Hz. After the mother ship power generation system generates electricity, it is stepped up by the step-up system composed of a voltage regulator and a step-up transformer. In some systems, a frequency converter may also be introduced to convert the frequency. The stepped-up electric energy is transmitted through a long-distance composite umbilical cable to power the underwater high-voltage motor, which drives the hydraulic pump to rotate, thereby providing power for the entire hydraulic system. On the other hand, the electric energy transmitted to the seabed will also go through the step-down link, and after the step-down, it will power other low-voltage electrical loads of the equipment.

[0073] like Figure 2 As shown in the figure, the overall design of the AC power supply system is divided into two parts: above water and underwater. The boost device consists of a low-voltage regulator and an isolation boost transformer. The working principle is as follows Figure 3 As shown, for example, the three-phase 380V incoming line of the ship's electrical system is adjusted to 0-420V by the voltage regulator, and then connected to a three-phase step-up isolation transformer to increase it to 0-4400V adjustable, and the built-in control cabinet and display unit are used for manual and automatic voltage regulation. This combination mode can obtain a stable voltage output, and can achieve electrical isolation and enhance system safety. The main task of the low-voltage voltage regulator is to ensure that the output voltage remains stable when the input voltage changes within a certain range, and to eliminate the fluctuation of the grid voltage before entering the next step to provide a relatively constant voltage. The working principle of the three-phase voltage regulator is as follows Figure 4 The function of the isolation step-up transformer is to increase the stable voltage output by the voltage regulator to the required voltage level, and to electrically isolate the input and output ends, thereby improving the safety of the system and reducing interference. The working principle of the three-phase isolation step-up transformer is as follows: Figure 5 shown.

[0074] The basic composition and structure of deep-sea armored umbilical cable Figure 6 As shown in FIG. 1 , the basic characteristics of the umbilical cable are mainly to study the characteristic parameters of the cable such as resistance, capacitance, and inductance, and use these characteristic parameters to establish an equivalent circuit model consistent with the real cable. In this embodiment, a π-shaped equivalent circuit is established, as shown in FIG. Figure 7 As shown, Figure 7 The equivalent model is transformed into an impedance model as Figure 8As shown, the transmission characteristics are analyzed. The expression of the impedance model is shown in formula (1), which mainly analyzes the voltage drop characteristics of the transmission line.

[0075] Based on the characteristic parameters of the umbilical cable, a π-shaped equivalent circuit model is constructed and converted into an impedance model, which is expressed as:

[0076]

[0077] Where Z is the line impedance and inductance, Y is the circuit capacitive reactance, r 1 is the resistance per unit length of cable, l is the length of the umbilical cable, x 1 is the inductance of the cable per unit length, f is the power frequency, L 1 is the inductance per unit length of the cable, b 1 is the capacitance per unit length of the cable.

[0078] The voltage and current at the head end of the umbilical cable are obtained based on the π-shaped equivalent circuit model:

[0079]

[0080] Converted into matrix form:

[0081]

[0082] Among them, U 1 is the voltage at the head end of the umbilical cable, I 1 is the umbilical cable current.

[0083] The power transmission characteristics of the umbilical cable can be calculated according to the formula. According to the voltage and power data required by the underwater control system load, the output parameters of the surface power equipment are derived, and the performance parameters of the underwater control system are obtained to determine the power loss on the power equipment and the umbilical cable.

[0084] The specific requirements for starting high-voltage motors in deep sea water are as follows: factors to be considered include starting current, starting torque, load driving capacity, starting reliability, system simplicity, cost and volume, etc. Secondly, since the motor needs to drive the pump group, the torque requirement is high, and it is necessary to ensure that the selected starting method can meet the needs of driving the pump group. In addition, under the premise of ensuring load and reliability, the starting current is controlled to reduce the impact on the power grid and equipment.

[0085] To start an underwater high-voltage motor, it is necessary to calculate the rated torque of the motor, the output power of the pump driven by the motor, the input power of the pump, the starting torque required to drive the pump group, and the electromagnetic torque of the motor.

[0086] The rated torque of the motor is calculated as follows:

[0087]

[0088] Among them, T is the electromagnetic torque of the motor; P is the motor power; n is the motor speed;

[0089] The output power of the pump driven by the motor is calculated as follows:

[0090] P out =p s ×D m ×ω(5),

[0091] Among them, D m is the maximum displacement of the pump, ω is the speed, p s To start the working pressure;

[0092] The input power of the pump is calculated as follows:

[0093]

[0094] Where η is the efficiency of the pump;

[0095] The starting torque required to drive the pump group is calculated as follows:

[0096]

[0097] Among them, n N is the rated speed;

[0098] The calculation of the motor electromagnetic torque is as follows:

[0099]

[0100] Among them, U 1 is the voltage of the stator winding; f 1 is the AC frequency; s is the slip rate; m 1 ,p,R 1 ,X 1 ,R′ 2 , X′ 2 These are motor-specific parameters, and their changes can be ignored during the startup process.

[0101] When selecting the starting mode, the actual starting torque can be calculated according to the electromagnetic torque formula to make the actual torque greater than the starting torque required to drive the pump group.

[0102] In the power supply system, a three-phase PWM rectifier is used to convert low-voltage AC into DC. Its topology is as follows: Fig. 9 As shown, the energy of the rectifier flows from the AC side to the DC side, where e a , e b , e c Represent the three-phase voltage on the AC side, e Lrepresents the DC electromotive force, L is the AC side filter inductance, R is the inductor equivalent resistance, i a ,i b ,i c is the current flowing through the three-phase filter inductor, C dc is the DC side voltage stabilizing capacitor, R L is the DC side load, v dc is the DC bus voltage.

[0103] Fig.10 is the control block diagram of the three-phase PWM rectifier, where V abc The actual voltage measured by the rectifier AC, I abc For AC measurement of actual current, i d 、i q are the actual values ​​of the d and q axis current components obtained after the Park transformation of the filter inductor current. The actual DC bus voltage v dc With a given value v dcref By comparison, the active current given value i is obtained after PI adjustment of the voltage outer loop. dref . Reactive current setting value i qref =0. will i dref and i qref Respectively with i d and i q Compare, and after PI adjustment of the current inner loop, get the voltage reference component on the AC side. d and ωLi q The abc-dq conversion is then performed and input into the PWM module to generate the control signal of the rectifier.

[0104] The backup battery is connected to the DC bus through a DC-DC converter, which is convenient for controlling the charging and discharging of the backup battery. The control block diagram is as follows: Fig.11 As shown. Where: V bus is the actual value of bus voltage; V bus-ref is the reference value of bus voltage; I b is the current flowing through the battery; I bref The rated value of the current flowing through the battery. The PI double closed-loop control of the voltage outer loop and the current inner loop accurately controls the charge and discharge of the backup battery.

[0105] The power of most low-voltage electrical equipment in the power supply system, such as controllers, monitoring lighting systems, and communication systems, remains constant, so the whole system can be regarded as a constant power load. In the simulation system, the above system can be equivalent to a constant power load under closed-loop control. The schematic diagram is shown in the figure. Fig.12 shown.

[0106] The present invention also provides a simulation method for a deep-sea underwater equipment AC power supply system based on Matlab / Simulink, comprising:

[0107] Model the important components of the AC power supply system of deep-sea underwater equipment, and establish a simulation model of the entire power supply system based on the simulation parameters of the system;

[0108] The mother ship power source generates a preset alternating current, and the voltage is increased to the target voltage value by the booster device;

[0109] The electric energy is transmitted through the umbilical cable, one way is to supply power to the underwater high-voltage motor, and the other way is stepped down to a preset voltage value by a step-down transformer;

[0110] The alternating current with a preset voltage value is converted into direct current with a preset voltage value by rectifying with a rectifier;

[0111] By collecting simulation waveforms of key parts of the power supply system, including the generation side, high voltage side, motor side, and DC low voltage side, the operating status of the entire power supply system and the rationality of the power supply system design can be judged, the parameters of the power supply equipment can be changed in real time, and the parameters can be optimized through simulation waveforms to complete the simulation verification of the power supply system.

[0112] Specifically, when designing a power supply system, it is necessary to simulate and verify the power supply system of the equipment in advance, and verify the feasibility of the power supply system design scheme and the parameters of each component. The present invention uses MATLAB / Simulink software to build a simulation model of the AC power supply system of deep-sea underwater equipment transmitted through an umbilical cable, such as Fig.13 As shown in Figure 1, the simulation model mainly includes: three-phase AC source, cable transmission model, step-up and step-down transformers, three-phase asynchronous motors, rectifiers, DC / DC converters, backup batteries, loads, etc. The simulation parameters are shown in Table 1. In the AC power supply system design simulation method based on MATLAB / Simulink, the design scheme and parameters of the power supply system are set as follows: the 380V / 50Hz AC source on the mother ship is boosted to 3300V by a booster device, and the electric energy is transmitted through the umbilical cable. On the one hand, it supplies power to the underwater high-voltage motor, and on the other hand, it is stepped down to 380V by a step-down transformer, and then rectified by a rectifier to convert the 380V AC into 24V DC, which supplies power to the controller, lighting, monitoring and other electrical equipment, and charges the backup battery energy storage system at the same time.

[0113] Table 1

[0114]

[0115] like Fig.13 As shown, the power supply system simulation model includes Fig.13 (a) Main circuit, Fig.13(b) three-phase power module, Fig.13 (c) Umbilical cable transmission π-type equivalent model subsystem, Fig.13 (d) three-phase rectifier module, Fig.13 (e) three-phase rectifier control module, Fig.13 (f) Constant power load module, Fig.13 (g) backup battery and its control module;

[0116] The voltage and current waveforms of the three-phase AC source are as follows Fig.14 As shown in the figure, it can be seen that the three-phase AC power generation system generates stable 380V / 50Hz AC power.

[0117] After the three-phase AC power is stepped up by the step-up transformer, the voltage and current waveforms on the high-voltage side are as follows: Fig.15 As shown in the figure, the voltage on the high-voltage side is 3300V, and the voltage and current waveforms are not distorted and are relatively stable, which meets the requirements for powering underwater high-voltage motors.

[0118] The rotor, stator current, speed, and motor torque waveforms of underwater high-pressure oil-immersed three-phase asynchronous motors are as follows: Fig.16 As shown in the figure, the speed and torque of the three-phase asynchronous motor reach the rated value after 0.15s, and the starting time is reasonable.

[0119] After being rectified by the rectifier, the low-voltage AC power is converted into DC power. The voltage on the low-voltage DC side is Fig.17 As shown in the figure, it can be seen that the low-voltage DC side voltage is stabilized at 24V at 0.4s, which can power the controller and communication equipment and charge the backup battery through the DC-DC converter.

[0120] By collecting the simulation waveforms of the key parts of the power generation side, high voltage side, motor side, and DC low voltage side, the operating status of the entire power supply system and the rationality of the power supply scheme design can be judged, and the parameters of the power supply equipment can be changed in real time, and the parameters can be optimized through the simulation waveform. In summary, the application of MATLAB / Simulink tools in the design and verification of deep-sea underwater equipment power supply systems proposed in the present invention. By simulating and analyzing the power supply system, the system design efficiency is improved, the system reliability is enhanced, the operation and performance are optimized, and the control strategy development is supported.

[0121] By collecting the simulation waveforms of the key parts of the power generation side, high voltage side, motor side, and DC low voltage side, the operating status of the entire power supply system and the rationality of the power supply scheme design can be judged, and the parameters of the power supply equipment can be changed in real time, and the parameters can be optimized through the simulation waveform. In summary, the application of MATLAB / Simulink tools in the design and verification of deep-sea underwater equipment power supply systems proposed in the present invention. By simulating and analyzing the power supply system, the system design efficiency is improved, the system reliability is enhanced, the operation and performance are optimized, and the control strategy development is supported.

[0122] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. The AC power supply system for deep-sea underwater equipment based on Matlab / Simulink is characterized by: include: Mother ship power supply, water ascent device, umbilical cable, underwater high-voltage motor, underwater step-down device, converter, hydraulic system and low-voltage DC load; The mother ship power supply is used to provide three-phase alternating current to the power supply system; The underwater boosting device, which is composed of a low-voltage voltage regulator and an isolation boosting transformer, is used to receive the alternating current from the mother ship power supply and regulate the electric energy, and transmit the regulated electric energy to the umbilical cable; The umbilical cable is used to transmit electrical energy to the seabed. After the electrical energy reaches the seabed, one path directly supplies power to the underwater high-voltage motor to drive the hydraulic pump and provide energy for the underwater hydraulic system; the other path passes through the underwater pressure reducing device, and after voltage reduction and rectification, it supplies power to other low-voltage electrical loads of the underwater equipment.

2. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 1, characterized in that: The water pressure boosting device comprises a low voltage regulator and an isolation boosting transformer; The low voltage regulator is used to ensure that the output voltage remains stable when the input voltage varies within a certain range; The isolation step-up transformer is used to increase the stable voltage output by the voltage regulator to a required voltage level and to electrically isolate the input end from the output end.

3. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 1, characterized in that: A π-shaped equivalent circuit model is constructed based on the characteristic parameters of the umbilical cable, and the π-shaped equivalent circuit model is converted into an impedance model, which is expressed as: Where Z is the line impedance and inductance, Y is the circuit capacitive reactance, r1 is the resistance per unit length of cable, l is the umbilical cable length, x1 is the inductance per unit length of cable, f is the power frequency, L1 is the inductance per unit length of cable, and b1 is the capacitance per unit length of cable.

4. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 3, characterized in that: The voltage and current at the head end of the umbilical cable are obtained based on the π-shaped equivalent circuit model, including: Converted into matrix form: Among them, U1 is the voltage at the head end of the umbilical cable, and I1 is the current of the umbilical cable.

5. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 1, characterized in that: To start the underwater high-voltage motor, it is necessary to calculate the rated torque of the motor, the output power of the pump driven by the motor, the input power of the pump, the starting torque required to drive the pump group, and the electromagnetic torque of the motor. The rated torque of the motor is calculated as follows: Among them, T is the electromagnetic torque of the motor; P is the motor power; n is the motor speed; The output power of the pump driven by the motor is calculated as follows: P out =p s ×D m ×ω, Among them, D m is the maximum displacement of the pump, ω is the speed, p s To start the working pressure; The input power of the pump is calculated as follows: Where η is the efficiency of the pump; The starting torque required to drive the pump group is calculated as follows: Among them, n N is the rated speed; The calculation of the motor electromagnetic torque is as follows: Among them, U1 is the voltage of the stator winding; f1 is the AC frequency; s is the slip rate; m1, p, R1, X1, R′2, X′2 are the specific parameters of the motor respectively.

6. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 1, characterized in that: The converter device converts low voltage AC power into DC power to supply power to the controller, communication equipment, monitoring and lighting equipment.

7. The deep-sea underwater equipment AC power supply system based on Matlab / Simulink as claimed in claim 6, characterized in that: The DC load equivalent model is established to equate the DC load to a constant power load under closed-loop control.

8. A simulation method for deep-sea underwater equipment AC power supply system based on Matlab / Simulink according to any one of claims 1 to 7, characterized in that: Model the important components of the AC power supply system of deep-sea underwater equipment, and establish a simulation model of the entire power supply system based on the simulation parameters of the system; The mother ship power source generates a preset alternating current, and the voltage is increased to the target voltage value by the booster device; The electric energy is transmitted through the umbilical cable, one way is to supply power to the underwater high-voltage motor, and the other way is stepped down to a preset voltage value by a step-down transformer; The alternating current with a preset voltage value is converted into direct current with a preset voltage value by rectifying with a rectifier; By collecting simulation waveforms of key parts of the power supply system, including the generation side, high voltage side, motor side, and DC low voltage side, the operating status of the entire power supply system and the rationality of the power supply system design can be judged, the parameters of the power supply equipment can be changed in real time, and the parameters can be optimized through simulation waveforms to complete the simulation of the power supply system.

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