A steam electric propulsion test system

Abstract

This invention discloses a steam-electric propulsion test system, relating to the field of marine technology. The system includes: a steam turbine generator, a frequency converter, a propulsion motor, a test monitoring device, a steam supply device, a steam discharge device, a hydraulic dynamometer, and a sensor array. The steam supply device outputs steam to the steam turbine generator via a steam supply header to perform work. The steam turbine generator supplies power to the propulsion motor via the frequency converter. The propulsion motor is directly connected to the hydraulic dynamometer, which simulates the load output power. The steam discharge device is located on a side branch of the steam supply header. The test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the steam supply header fed back by the sensor array, ensuring stable steam supply pressure during the test. The test monitoring device determines the inlet and outlet valve openings of the hydraulic dynamometer based on the current rotational speed of the hydraulic dynamometer fed back by the sensor array, enabling automatic tracking of the dynamometer's output power and ensuring accurate and rapid matching of the propulsion load output power.

Description

Technical Field

[0001] This invention relates to the field of marine technology, and in particular to a steam-electric propulsion test system. Background Technology

[0002] Electric propulsion offers numerous advantages over traditional ship propulsion, such as flexible power equipment layout, high space utilization, and a high degree of intelligent ship energy management. Therefore, electric propulsion is a crucial development direction for current ship propulsion systems. Generator sets are the primary power source for electric propulsion systems and a vital component. Steam turbine generators, due to their high single-unit power, simple structure, and good stability, are a popular choice for ship generator sets. Steam-electric propulsion is currently one of the research directions in ship electric propulsion.

[0003] While electric propulsion is the current development direction in the field of marine power, it has not yet been widely applied, and there is limited reference information on land-based test platforms for electric propulsion. Tests involving electric propulsion powered by steam turbine generators are even more difficult to find. The closest patent is CN213473472U, "A Hybrid Power System Test Platform for Simulating Ship Operating States." The test platform described in this patent consists of a power supply, a propulsion motor, a resistive-inductive load box, and an eddy current dynamometer. The power supply is a diesel generator set, a lithium battery pack, and a supercapacitor. The power supply provides power to the ship's electrical load and daily load. The electrical load is the propulsion motor and its connected eddy current dynamometer, and the daily load is the resistive-inductive load box.

[0004] Compared to diesel generator sets, steam turbine generators offer advantages such as better stability, stronger overload capacity, and lower noise and vibration, making them promising for applications in marine electric propulsion. However, steam turbine generators require additional steam supply equipment, which is complex and demanding, limiting their use in the marine sector, and consequently, steam-electric propulsion tests are relatively rare. Because electric propulsion tests involve a wide and rapid speed range and drastic changes in propulsion power, the steam consumption of the steam turbine generator also fluctuates dramatically. However, the steam supply equipment adjusts slowly, making it difficult to keep up with the changes in steam consumption during tests, thus easily leading to turbine generator tripping and shutdown. Summary of the Invention

[0005] To address the aforementioned problems and technical requirements, the inventors have proposed a steam-electric propulsion test system. This system uses a steam turbine generator as the power source for the propulsion system. The system equipment also includes a frequency converter, a propulsion motor, and a hydraulic dynamometer as the load. Furthermore, the supporting equipment includes a steam supply device, a steam discharge device, a test monitoring device, and a sensor array. The technical solution of this invention is as follows:

[0006] A steam-electric propulsion test system includes a steam turbine generator, a frequency converter, a propulsion motor, a test monitoring device, a steam supply device, a steam discharge device, a hydraulic dynamometer, and a sensor group. The steam supply device outputs steam to the steam turbine generator through a steam supply header to perform work. The steam turbine generator supplies power to the propulsion motor through the frequency converter. The propulsion motor is directly connected to the hydraulic dynamometer, which is used to simulate the load output power.

[0007] The steam discharge device is installed on the bypass branch of the steam supply main pipe. The test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the steam supply main pipe fed back by the sensor group. The bypass steam flow is adjusted by adjusting the valve opening of the steam discharge device to achieve stable steam pressure of the steam supply main pipe during the propulsion test.

[0008] The test monitoring device determines the opening degree of the inlet and outlet valves of the hydraulic dynamometer based on the current rotational speed of the hydraulic dynamometer fed back by the sensor group, thereby realizing the automatic tracking of the dynamometer's output power.

[0009] A further technical solution is that the test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the steam supply header fed back by the sensor group, including:

[0010] The actual steam pressure of the steam supply header and the rated operating pressure of the steam turbine generator are used as inputs to the PID controller. The PID parameters of the PID controller are adjusted using a segmented PID algorithm. The PID controller outputs a corresponding opening adjustment signal, and the test monitoring device controls the valve opening of the steam discharge device according to the opening adjustment signal.

[0011] A further technical solution involves using a segmented PID algorithm to adjust the PID parameters of the PID controller, including in the test monitoring device:

[0012] The range of rotational speed of the hydraulic dynamometer is divided into multiple speed segments. For each speed segment, a corresponding proportional gain, integral time, and derivative time parameter of the PID controller is set. The test monitoring device determines the proportional gain, integral time, and derivative time parameter of the PID controller corresponding to the speed segment based on the current rotational speed of the hydraulic dynamometer fed back by the sensor group. These parameters are used as the PID parameters of the PID controller at the current rotational speed. The current rotational speed of the hydraulic dynamometer is consistent with the rotational speed of the propulsion motor.

[0013] A further technical solution is that the test monitoring device determines the opening degree of the inlet and outlet valves of the hydraulic dynamometer based on the current rotational speed of the hydraulic dynamometer fed back by the sensor group, including:

[0014] Substituting the current rotational speed of the hydraulic dynamometer fed back by the sensor group into the fitted characteristic curve, the output power of the dynamometer is obtained; based on the current rotational speed n of the hydraulic dynamometer...t and dynamometer output power P t The torque M of the hydraulic dynamometer was calculated by reverse calculation. t The expression is: M t =60P t / 2πn t Based on the relationship between the torque of the hydraulic dynamometer and the opening of the inlet and outlet valves, determine the opening of the inlet and outlet valves of the hydraulic dynamometer at the current speed.

[0015] A further technical solution involves using a test monitoring device to fit a characteristic curve based on the hydraulic dynamometer output power P and dynamometer rotation speed n required for each propulsion operating point, obtained in advance. The expression is: P = C1n 3 +C2n 2 +C3n;

[0016] C1, C2, and C3 are curve coefficients.

[0017] The further technical solution is that the sensor group includes a pressure sensor and a temperature sensor installed on the steam supply header, an angle-connected pressure tap orifice plate for measuring steam flow, an electrical sensor for collecting DC voltage and current output from the steam turbine generator and AC voltage and current output from the frequency converter, and a sensor for collecting the speed and torque of the hydraulic dynamometer; the test monitoring device determines the steam flow of the steam supply header based on the actual steam pressure and steam temperature of the steam supply header and the orifice plate differential pressure fed back by the sensor group.

[0018] A further technical solution involves substituting the actual steam pressure and temperature of the steam supply header fed back by the sensor group into the IFC1967 formula to calculate the current steam density of the steam supply header. Then, based on the steam density and the orifice plate differential pressure, the steam flow rate f of the steam supply header is determined. The expression is:

[0019]

[0020] Where d is the orifice diameter under the operating conditions of the orifice plate, ε is the orifice plate expandability coefficient, α is the orifice plate flow coefficient, Δp is the differential pressure of the corner orifice plate, and ρ is the current steam density calculated by the IFC1967 formula.

[0021] A further technical solution is that, in the test monitoring device, the distorted steady-state data fed back by the sensor group is processed by a band-stop digital filter to perform digital signal filtering for the interference frequency band, so as to obtain accurate and stable test data.

[0022] A further technical solution is that when an equipment failure occurs during the propulsion test, the steam turbine generator stops, and the test monitoring device controls the valve of the steam discharge device to switch to the normally open state to release steam from the steam supply header.

[0023] The further technical solution is to establish a distributed control system with test monitoring device, steam supply device, steam discharge device and hydraulic dynamometer as the main equipment. The test monitoring device serves as the master station of the distributed control system and establishes data communication with the other equipment nodes of the distributed control system based on Ethernet OPC, Modbus and Profinet.

[0024] The beneficial technical effects of this invention are:

[0025] 1) By opening a bypass branch on the steam supply main pipe and installing a steam discharge device based on segmented PID algorithm control on the bypass branch, the steam discharge device can be used to adjust the bypass steam flow rate, ensuring the stability of the steam supply pressure during the propulsion test and solving the problem of steam flow rate adjustment caused by drastic changes in steam flow rate during the propulsion test.

[0026] 2) Due to the rapid power change during high-speed propulsion, it is difficult to quickly and accurately match the power corresponding to the rotational speed using manual control. Therefore, this system has developed an automatic following mode for the output power of the hydraulic dynamometer to ensure accurate and rapid matching of the output power of the propulsion load.

[0027] 3) This system can also collect and process various test data in the steam electric propulsion test. In response to the electromagnetic interference problem of sensor signals, this system adopts digital filtering technology. Digital filtering has the advantages of convenient and flexible filtering adjustment, and is a better way to process clutter signals with difficult-to-determine interference frequency bands.

[0028] 4) This system will also serve as a distributed control system for the test monitoring device, steam supply device, steam discharge device, and hydraulic dynamometer of the test equipment, establishing data communication with the test equipment to facilitate monitoring and management by test personnel. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the steam-electric propulsion test system provided in this application.

[0030] Figure 2 This is the steam-electric propulsion test flowchart provided in this application. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1As shown, this embodiment provides a steam-electric propulsion test system, including a steam turbine generator, a frequency converter, and a propulsion motor as test equipment, and a test monitoring device, a steam supply device, a steam discharge device, a hydraulic dynamometer, and a sensor group as auxiliary test equipment. The steam supply device outputs steam to the steam turbine generator through the steam supply header 1 to perform work; the steam turbine generator supplies power to the propulsion motor through the frequency converter. Specifically, the steam turbine generator obtains DC power through a bridge-type fully controlled rectifier circuit and transmits it to the frequency converter. The frequency converter outputs AC power to the propulsion motor through sinusoidal pulse width modulation technology. By changing the AC power frequency, the propulsion motor obtains different speeds; the propulsion motor is directly connected to the hydraulic dynamometer, which is used to simulate the load output power. In the marine field, the load is the ship's propeller blades.

[0033] Steam-electric propulsion tests place high demands on the steam supply system because the output speed and power of the propulsion motor have a near-cubic relationship. At low speeds, power changes little with speed adjustment, while at high speeds, power changes significantly. It is difficult for the steam supply system alone to keep up with the drastic, non-linear changes in steam consumption caused by power variations. Therefore, a bypass branch 2 is established on the main steam supply line 1, and a steam discharge device is installed on bypass branch 2. During the test, the steam supply system provides full-load steam consumption. The test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the main steam supply line as fed back by a pressure sensor located on the main line. By adjusting the valve opening, the bypass steam flow rate is regulated to ensure stable steam pressure in the main steam supply line 1 during the propulsion test.

[0034] Because the steam consumption rate changes differently at low and high speeds of the propulsion motor, a segmented PID algorithm control is adopted. The steam pressure of the steam supply header is the controlled object, the rated operating pressure of the turbine generator is the target value, and the pressure value measured by the pressure sensor is used as the feedback value. The specific implementation method for determining the valve opening of the steam discharge device is as follows: The test monitoring device uses the actual steam pressure and rated operating pressure of the steam supply header as inputs to the PID controller, and adjusts the PID parameters of the PID controller using a segmented PID algorithm. The PID controller outputs a corresponding opening adjustment signal, and the test monitoring device controls the valve opening of the steam discharge device according to the opening adjustment signal. The method for adjusting the PID parameters is as follows: The range of the hydraulic dynamometer's rotational speed is divided into multiple speed segments, and each speed segment is set with corresponding proportional gain, integral time, and derivative time parameters for the PID controller. The test monitoring device determines the proportional gain, integral time, and derivative time parameters of the PID controller corresponding to the speed segment based on the current rotational speed of the hydraulic dynamometer fed back by the sensor group, and uses these parameters as the PID parameters for the PID controller at the current speed.

[0035] The output power of the hydraulic dynamometer is determined by the dynamometer's rotational speed and torque, as shown in equation (1):

[0036] M=60P / 2πn (1)

[0037] Where P is the output power of the dynamometer, M is the torque of the dynamometer, and n is the speed of the dynamometer.

[0038] The dynamometer's rotational speed is the same as the propulsion motor's speed. The dynamometer's torque is determined by the internal circulating water volume. Under a constant inlet and outlet water pressure difference, the torque corresponds to the opening of the inlet and outlet valves. Therefore, adjusting the opening of the inlet and outlet valves controls the internal water volume, thereby controlling the dynamometer's torque and thus its output power. Since the propulsion motor rotates both forward and reverse during the test, a bidirectional hydraulic dynamometer is used, with two circulating water circuits corresponding to forward and reverse operation. During the propulsion test, the dynamometer needs to quickly and accurately match the corresponding output power to the propulsion motor's rotational speed. Manual control of the dynamometer is difficult to achieve this function; therefore, this system developed an automatic output power following mode, i.e., N... 3 The automatic control mode operates on the principle that ship propulsion power and rotational speed are approximately cubic. 3 The automatic control mode requires acquiring the required dynamometer output power P and dynamometer speed n at each propulsion operating point before the test begins, and then fitting the characteristic curve to store it in the test monitoring device. The curve expression is: P = C1n 3 +C2n 2 +C3n (2)

[0039] C1, C2, and C3 are curve coefficients.

[0040] Therefore, during the test, the test monitoring device activated N. 3 In automatic control mode, the dynamometer output power is automatically followed. Specifically, the test monitoring device transmits the current rotational speed n of the hydraulic dynamometer, fed back from the sensor group. t Substituting the fitted characteristic curve (2), the output power P of the dynamometer is quickly matched. t According to the current rotational speed n of the hydraulic dynamometer t and dynamometer output power P t Substitute into equation (1) to calculate the torque M of the hydraulic dynamometer. t Based on the relationship between the torque of the hydraulic dynamometer and the opening degrees of the inlet and outlet valves, the current rotational speed n is determined. t The opening degree of the inlet and outlet valves of the hydraulic dynamometer.

[0041] The sensor group includes pressure and temperature sensors installed on the steam supply header, an angle tap pressure plate for measuring steam flow to measure steam parameters, electrical sensors for collecting AC and DC voltage and current parameters to measure electrical parameters output by the steam turbine generator and frequency converter, and sensors for collecting speed and torque of the hydraulic dynamometer to measure the output parameters of the dynamometer. Substituting into equation (1) yields the actual output power of the dynamometer.

[0042] For the acquired steam parameters, the test monitoring device determines the steam flow rate of the steam supply header based on the actual steam pressure and temperature of the header fed back by the sensor group, combined with the orifice differential pressure. Specifically, the test monitoring device substitutes the actual steam pressure and temperature of the header fed back by the sensor group into the IFC1967 formula to calculate the current steam density of the header, and then calculates the steam flow rate f of the header based on the steam density and the orifice differential pressure. The expression is:

[0043]

[0044] Where d is the orifice diameter under the operating conditions of the orifice plate, ε is the orifice plate expandability coefficient, α is the orifice plate flow coefficient, Δp is the differential pressure of the corner orifice plate, and ρ is the current steam density calculated by the IFC1967 formula.

[0045] The test monitoring device uses a high sampling rate and multi-channel modules to synchronously collect electrical parameters output by the steam turbine generator and frequency converter, displays the dynamic data waveforms of the electrical parameters, performs a fast Fourier transform on the data waveforms to obtain the DC, fundamental, and harmonic components, and calculates test data such as ripple coefficient, harmonic distortion rate, AC frequency, and power factor according to the formula definitions.

[0046] Some sensor groups may experience severe electromagnetic interference due to their proximity to high-power equipment such as frequency converters equipped with high-frequency switching devices, resulting in distorted steady-state data. Therefore, the test monitoring device uses a band-stop digital filter to perform digital signal filtering on the distorted steady-state data fed back by the sensor groups to target the interference frequency band and obtain accurate and stable test data.

[0047] During the test, the steam supply device, steam discharge device, and hydraulic dynamometer cooperated with each other. In order to facilitate the monitoring and operation by the test personnel, a distributed control system (DCS) was established with the test monitoring device, steam supply device, steam discharge device, and hydraulic dynamometer as the main equipment. The test monitoring device, as the master station of the DCS, established OPC, Modbus, and Profinet data communication with the other equipment nodes of the DCS based on Ethernet.

[0048] Combination Figure 2As shown, the process of performing a steam-electric propulsion test using the above system is briefly described: Before the propulsion test begins, the DCS master station issues a command, the steam venting device opens to the corresponding degree for steam bypass, and the steam supply device continuously supplies steam until the steam pressure in the steam supply header rises to the rated operating pressure of the turbine generator. Then, the steam venting device engages in segmented PID algorithm control, and the hydraulic dynamometer is activated at N... 3 In automatic control mode, the turbine generator starts until the rated voltage is established. Once preparation is complete, the propulsion test begins. The frequency converter starts and enters propulsion mode. The propulsion motor gradually increases its speed from rest to the maximum speed, then decreases to zero and reverses. The propulsion power (consistent with the dynamometer output power) first increases, then decreases, and then increases again. The steam discharge device closes, then opens, and then closes again according to pressure changes. The hydraulic dynamometer adjusts the opening of the inlet and outlet valves according to speed changes, automatically matching the propulsion power. If equipment failure occurs during the propulsion test, the turbine generator will shut down urgently. At this time, the turbine generator main steam valve will close rapidly, and the test monitoring device will control the steam discharge device valve to switch to the normally open state to release steam from the steam supply header and reduce the steam pressure in the steam supply header.

[0049] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A steam-electric propulsion test system, characterized in that, It includes a steam turbine generator, a frequency converter, a propulsion motor, a test and monitoring device, a steam supply device, a steam discharge device, a hydraulic dynamometer, and a sensor array; the steam supply device outputs steam to the steam turbine generator through a steam supply header to perform work, the steam turbine generator supplies power to the propulsion motor through the frequency converter, the propulsion motor is directly connected to the hydraulic dynamometer, and the hydraulic dynamometer is used to simulate load output power; The steam discharge device is installed on the bypass branch of the steam supply main pipe. The test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the steam supply main pipe fed back by the sensor group. The bypass steam flow rate is adjusted by adjusting the valve opening of the steam discharge device to achieve stable steam pressure of the steam supply main pipe during the propulsion test. The test monitoring device calculates the required hydraulic dynamometer output power based on the pre-acquired propulsion operating conditions at each point. P and dynamometer speed n The characteristic curve is obtained by fitting the curve; the current rotational speed of the hydraulic dynamometer fed back by the sensor group is substituted into the fitted characteristic curve to obtain the output power of the dynamometer; and the torque of the hydraulic dynamometer is calculated based on the current rotational speed and the output power of the hydraulic dynamometer. M t Based on the correspondence between the torque of the hydraulic dynamometer and the opening of the inlet valve and the outlet valve, the opening of the inlet and outlet valves of the hydraulic dynamometer at the current speed is determined, so as to realize the automatic following of the output power of the dynamometer. The characteristic curve expression is as follows: , C 1. C 2. C 3 represents the curve coefficient; , n t The current rotational speed of the hydraulic dynamometer. P t The output power of the dynamometer is obtained through the characteristic curve.

2. The steam-electric propulsion test system according to claim 1, characterized in that, The test monitoring device determines the valve opening of the steam discharge device based on the actual steam pressure of the steam supply header fed back by the sensor group, including, in the test monitoring device: The actual steam pressure of the steam supply header and the rated operating pressure of the steam turbine generator are used as inputs to the PID controller. A segmented PID algorithm is used to adjust the PID parameters of the PID controller. The PID controller outputs a corresponding opening adjustment signal. The test monitoring device controls the valve opening of the steam discharge device according to the opening adjustment signal.

3. The steam-electric propulsion test system according to claim 2, characterized in that, Adjusting the PID parameters of the PID controller using a segmented PID algorithm includes, in the test monitoring device: The range of rotational speed of the hydraulic dynamometer is divided into multiple speed segments. Each speed segment is configured with a corresponding proportional gain, integral time, and derivative time parameter of the PID controller. The test monitoring device determines the proportional gain, integral time, and derivative time parameter of the PID controller corresponding to the speed segment based on the current rotational speed of the hydraulic dynamometer fed back by the sensor group, and uses these parameters as the PID parameters of the PID controller at the current rotational speed. The current rotational speed of the hydraulic dynamometer is consistent with the rotational speed of the propulsion motor.

4. The steam-electric propulsion test system according to claim 1, characterized in that, The sensor group includes a pressure sensor and a temperature sensor installed on the steam supply header, an angle-connected pressure tap orifice plate for measuring steam flow, an electrical sensor for collecting DC voltage and current output from the turbine generator and AC voltage and current output from the frequency converter, and a sensor for collecting the speed and torque of the hydraulic dynamometer. The test monitoring device determines the steam flow of the steam supply header based on the actual steam pressure and steam temperature of the steam supply header fed back by the sensor group and the differential pressure of the orifice plate.

5. The steam-electric propulsion test system according to claim 4, characterized in that, In the test monitoring device, the actual steam pressure and steam temperature of the steam supply header fed back by the sensor group are substituted into the IFC1967 formula to calculate the current steam density of the steam supply header. Then, the steam flow rate of the steam supply header is determined based on the steam density and the orifice plate differential pressure. f The expression is: ； in, d This refers to the diameter of the orifice plate under its operating conditions. ε The coefficient of expansion of the orifice plate. α Let Δ be the orifice plate flow coefficient. p For differential pressure of the corner joint orifice plate, ρ The current steam density is calculated using the IFC1967 formula.

6. The steam-electric propulsion test system according to claim 4, characterized in that, In the test monitoring device, the distorted steady-state data fed back by the sensor group is processed by a band-stop digital filter to perform digital signal filtering for the interference frequency band, so as to obtain accurate and stable test data.

7. The steam-electric propulsion test system according to any one of claims 1-6, characterized in that, When an equipment failure occurs during the propulsion test, the steam turbine generator stops, and the test monitoring device controls the valve of the steam discharge device to switch to the normally open state to release steam from the steam supply header.

8. The steam-electric propulsion test system according to any one of claims 1-6, characterized in that, A distributed control system is established with the test monitoring device, the steam supply device, the steam discharge device, and the hydraulic dynamometer as the main equipment. The test monitoring device serves as the master station of the distributed control system and establishes data communication with the other equipment nodes of the distributed control system based on Ethernet, using OPC, Modbus, and Profinet.

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