Magnetic suspension rack scaling prototype test platform for vibration isolation of steam turbine

Abstract

The invention relates to a magnetic suspension rack scaling prototype test platform for vibration isolation of a steam turbine, and the platform is characterized in that an upper rack and a lower rack in a basic structure of a suspension rack are connected through a plurality of electromagnets, and are used for introducing active control electromagnetic force between a vibration source and a load to realize structural support; each electromagnet is provided with a suspension vibration sensor which is used for collecting electromagnet suspension gap and vertical vibration data, when a steam turbine generator unit bearing platform bears a vibration excitation source, the suspension vibration sensors collect electromagnet suspension gap signals and acceleration signals in real time, and the signals are received, processed and transmitted through a control panel FPGA chip. And the DSP performs real-time current calculation based on the signals given by the FPGA, generates corresponding PWM waves after completing calculation based on the real-time suspension gap and acceleration signals of the suspension electromagnet, acts on the driving plate, controls the on-off of the power switch IGBT, generates corresponding control current and outputs the control current to the suspension electromagnet for suspension vibration isolation.

Description

Technical Field

[0001] The invention relates to a vibration reduction and isolation test platform for a ship steam turbine unit, in particular to a magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation. Background Art

[0002] During the voyage of a ship, the vibration and noise of the ship have a negative impact on the stealth performance and detectability of the ship. Therefore, ship designers around the world are vigorously developing vibration and noise reduction technologies, especially when designing ships for special missions, taking noise reduction technology as a key tactical indicator. The mechanical noise of a ship is mainly due to the noise generated by mechanical vibration of mechanical equipment such as turbines during operation, and gears and other components during operation, which is the main source of vibration noise of ships.

[0003] Vibration reduction and noise reduction technologies are currently divided into two categories. One is a passive method based on shock absorbers, also known as passive vibration control technology. It has a simple structure and low cost and has been widely used in vibration control. Passive vibration control does not install an energy device to provide energy. It does not require an external power supply or a control system during operation. It is commonly composed of a combination of elastic elements, damping elements or inertial elements, such as steel springs, air springs, polymer materials, etc. Passive vibration control technology can reduce the vibration intensity transmitted to the damped body, or consume the kinetic energy of vibration by doing negative work to achieve the purpose of vibration reduction. Although passive vibration control technology has achieved good results, once the design and installation are completed, the output characteristic parameters (stiffness, damping, etc.) of the system cannot be adjusted according to the actual working conditions, which has great limitations. With the current development of shaft transmission becoming increasingly high-speed and high-power, the dynamic environment is more severe than before. It is difficult to flexibly adapt to the changing vibration reduction and isolation requirements by simply changing the configuration scheme. The research on active vibration reduction technology is essential.

[0004] Active vibration control technology, also known as active vibration control technology, uses vibration reduction devices with external energy input to achieve vibration reduction. Figure 1 As shown in the figure, it uses sensors to measure various state signals of the system (gap, acceleration, etc.), and generates control signals in the controller through feedforward or feedback, so that the vibration reduction force generated by the vibration reduction device and the vibration force of the system offset each other, thereby achieving the purpose of suppressing vibration. Compared with passive vibration control, active vibration control can dynamically adjust the system output characteristics in real time according to a given control strategy, has strong adaptability to the external environment, and has a larger vibration isolation bandwidth, which can not only overcome the shortcomings of passive vibration control, but also better meet the vibration control requirements.

[0005] At present, there are relatively few active vibration reduction and isolation technologies in the field of ships. According to the type of technology, they are mainly divided into electro-hydraulic vibration reduction technology and electromagnetic vibration reduction technology. Electro-hydraulic vibration reduction technology mainly monitors the vibration of the ship in real time through an electronic control system, and adjusts the oil pressure and flow in the hydraulic system to generate corresponding damping force to offset the vibration. However, this technology is highly dependent on hydraulic oil, and its performance is affected by the quality and state of the hydraulic oil. The working environment of the ship is complex, and the hydraulic oil is easily affected by factors such as pollution, deterioration or excessive temperature, which affects the vibration reduction effect. Electromagnetic vibration reduction technology uses electromagnetic force as the vibration reduction force. Through the interaction between the electromagnetic coil and the permanent magnet, the magnitude and direction of the electromagnetic force are adjusted in real time according to the vibration situation to achieve the vibration reduction effect. However, there is no mature research on the magnetic suspension vibration reduction and isolation device for marine steam turbine units. Other related electromagnetic vibration reduction platforms are still in their infancy, and have not fully considered the working characteristics of the steam turbine unit and the complexity of the marine environment. The steam turbine unit includes a steam turbine and a generator, etc., and vibrations of various frequency bands will exist when working at the same time. How to adjust the parameters of the electromagnetic vibration isolator to achieve the best vibration isolation effect is a problem that needs to be solved in the application of electromagnetic vibration isolators in this field. At the same time, ships will encounter various complex working conditions during navigation, such as wind, waves, tides, etc. Electromagnetic vibration isolators need to have good adaptability and be able to maintain a stable vibration isolation effect under different working conditions.

[0006] Therefore, it is necessary to propose the structure of a scaled prototype of the magnetic levitation frame of a steam turbine unit under marine conditions, modeling of the suspension control system and a method for suppressing vibration; to study the influence of different suspension control core algorithms, different filtering parameters, etc. on vibration transmission and suppression characteristics; and to evaluate the feasibility of applying the magnetic levitation frame in vibration suppression in marine steam turbine generator sets through scaled prototype tests. Summary of the invention

[0007] The present invention is to provide a scaled prototype test platform of a magnetic suspension frame for steam turbine vibration isolation, with the purpose of verifying the effect and feasibility of using the magnetic suspension active vibration isolation frame for steam turbine vibration isolation through the design and construction of a semi-physical simulation platform, and further optimizing the design of the magnetic suspension control system through the test platform, so as to provide test conditions and reference value for practical applications.

[0008] To achieve the above purpose, the technical solution of the present invention is: a magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation, including a suspension frame basic structure, an electromagnet, a suspension controller, a DC power supply cabinet, a suspension vibration sensor, a vibration isolator, and a valve frame. The upper frame and the lower frame in the basic structure of the suspension frame are connected by multiple electromagnets, which are used to introduce actively controlled electromagnetic forces between the vibration source and the load to achieve structural support, so that the vibration source and the load are completely out of mechanical contact; each electromagnet is equipped with a suspension vibration sensor, which is used to collect the suspension gap and vertical vibration data of the electromagnet. When the turbine generator set foundation carries the vibration excitation source, the suspension vibration sensor collects the suspension gap signal and acceleration signal of the electromagnet in real time, and receives, processes and transmits the signal through the control board FPGA chip. The DSP performs real-time current calculation based on the signal given by the FPGA, and generates a corresponding PWM wave after completing the calculation based on the real-time suspension gap and acceleration signal of the suspension electromagnet, which acts on the drive board to control the on and off of the power switch IGBT, and generates a corresponding control current output to the suspension electromagnet for suspension vibration isolation.

[0009] Furthermore, the basic structure of the suspension frame is composed of F rails, sleepers, an upper frame, a lower frame and a steam turbine generator set support.

[0010] Furthermore, two groups of electromagnets are respectively configured on the left and right sides of the basic structure of the suspension frame in the Y direction, and a suspension controller is used on each side to control the two-point suspension; a group of electromagnets is respectively configured on the front and rear sides in the X direction, and a suspension controller is used on both sides to control the two-point suspension.

[0011] Furthermore, each suspension controller has two suspension control boards and realizes hot standby redundancy through life signals. The suspension control circuit of each control board realizes input signal processing and output signal control based on DSP chip and FPGA chip. The FGPA chip processes the monitoring data of each sensor and the DSP chip calculates the control quantity.

[0012] Furthermore, when each suspension controller works normally, the suspension control board 1 sends a life signal to the suspension control board 2 based on the suspension gap signal and acceleration signal of the corresponding control point monitored by the suspension sensor. At this time, the suspension control board 2 only receives the suspension characteristic signal but does not output it. When the suspension control board 1 fails, the suspension control board 2 cannot receive the life signal given by the suspension control board 1 and takes over the output synchronously. The control output of the control module acts on the drive module to realize the current output in the suspension electromagnet. The four suspension points float together, and the suspension gap is controlled to be at the rated value to ensure the stability of the suspension.

[0013] Furthermore, two vibration isolations are performed between the lower frame and the valve frame through multiple rubber isolators, which together with the magnetic suspension vibration isolation achieve the overall vibration isolation effect of the steam turbine unit.

[0014] Furthermore, the valve frame is constructed with high-strength, low-weight materials to ensure the rigidity and lightness of the overall structure to adapt to the complex working environment of the ship.

[0015] The beneficial effects of the present invention are:

[0016] 1. The suspension function of the scaled prototype of the suspended vibration-damping frame was verified through a load-bearing static floating test, and the structure of the scaled prototype, the modeling of the suspension control system, and the feasibility of the vibration suppression method were verified.

[0017] 2. The magnetic levitation vibration isolation technology used in the present invention takes into account the working characteristics of the steam turbine, has good vibration isolation effects in all frequency bands, and has higher flexibility and adjustability than traditional passive vibration absorbers.

[0018] 3. Compared with the electro-hydraulic vibration reduction technology, the electromagnetic vibration isolation technology used in the present invention can maintain relatively stable performance in extreme temperature, humidity and corrosive environments due to its own technical characteristics, and is not easily affected by the environment. In addition, this technology usually does not involve the emission and use of harmful substances, and meets environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of an active vibration reduction device;

[0020] Figure 2 The simplified system diagram of the magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 2As shown, a scaled prototype test platform of a magnetic suspension frame for turbine vibration isolation of the present invention includes a basic structure of a suspension frame (including F rails, sleepers, a basic module of a suspension frame and a steam turbine generator set support), 8 electromagnets (two electromagnets are connected in series to form a group of electromagnets), 2 two-in-one suspension controllers, a 330V DC power supply cabinet, 4 suspension vibration sensors, 8 vibration isolators, and a valve frame. A group of electromagnets is equipped with a suspension vibration sensor for collecting electromagnet suspension gap and vertical vibration data. The valve frames are constructed of high-strength, low-weight materials to ensure the rigidity and lightness of the overall structure to adapt to the complex working environment of the ship. The modules on the left and right sides of the Y direction are respectively equipped with two groups of electromagnets, and each side uses a two-in-one suspension controller to control the two-point suspension. The modules on the front and rear sides of the X direction are respectively equipped with a group of electromagnets, and a two-in-one suspension controller is used on both sides to control the two-point suspension. Each two-in-one suspension controller has two suspension control boards and realizes hot standby redundancy through life signals. The suspension control circuit of each control board realizes input signal processing and output signal control based on DSP chip and FPGA chip. The monitoring data of each sensor is processed by FGPA chip, and the control quantity is calculated by DSP chip. When each suspension controller is working normally, the suspension control board 1 sends a life signal to the suspension control board 2 based on the suspension gap signal and acceleration signal of the corresponding control point monitored by the suspension sensor. At this time, the suspension control board 2 only receives the suspension characteristic signal but does not output. When the suspension control board 1 fails, the suspension control board 2 cannot receive the life signal given by the suspension control board 1, and takes over the output synchronously. The control output of the control module acts on the drive module to realize the current output in the suspension electromagnet. The four suspension points float together, control the suspension gap to be at the rated value, and ensure the stability of suspension.

[0023] The invention discloses a scaled-down prototype test platform of a magnetic suspension frame for steam turbine vibration isolation, which realizes structural support by introducing an actively controlled electromagnetic force between a vibration source and a load, so that the vibration source and the load are completely separated from mechanical contact. The magnitude of the electromagnetic force used for active vibration isolation can be realized by adjusting the excitation current of the electromagnet, so the static stiffness and dynamic vibration isolation effect of the scaled-down prototype test platform can be conveniently adjusted. Among them, when the steam turbine generator set bearing platform carries a vibration excitation source, the suspension vibration sensor can collect the suspension gap signal and acceleration signal of the electromagnet in real time, and receive, process and transmit the signal through the control board FPGA chip. The DSP performs real-time current calculation based on the signal given by the FPGA, generates a corresponding PWM wave after completing the calculation based on the real-time suspension gap and acceleration signal of the suspension electromagnet, acts on the drive board, controls the on and off of the power switch IGBT, and generates a corresponding control current output to the suspension electromagnet for suspension vibration isolation.

[0024] Furthermore, the suspension control board 1 and the suspension control board 2 send life signals to each other in real time. When the suspension control board 1 fails, the suspension control board 2 takes over the signal reception, processing and transmission.

[0025] Furthermore, eight rubber isolators are used between the lower frame and the valve frame for secondary vibration isolation, which together with the magnetic suspension vibration isolation achieves an overall vibration isolation effect for the steam turbine unit.

[0026] Example:

[0027] Eight counterweights are installed on the upper frame of the magnetic suspension vibration reduction frame. Each counterweight is 250kg, with a total load of 2t, simulating the actual load of the steam turbine unit.

[0028] When measuring the stability of the actual suspension control system, vertical acceleration sensors are installed at the key vibration locations of the upper frame and the feet of the lower frame. The relevant vibration data is measured by a data acquisition instrument, and the data is analyzed in the time and frequency domains to evaluate the rationality of the design of the magnetic suspension vibration isolation system.

[0029] From the time domain diagram of the test data, it can be seen that when in stable suspension, the vibration acceleration level of the upper and lower frames is maintained at around 90dB. Under the load simulating marine conditions, no additional substantial interference will be generated during the operation of the frames. It is reasonable to use it in the field of vibration isolation of steam turbines.

[0030] During normal testing, an electric motor with a rated speed of 3000 rpm (50 Hz) is installed on the upper frame support. Its speed is changed by a frequency converter, and eccentric bolts are installed on the rotor to achieve excitation of different frequency components to simulate the operation of a steam turbine. The vibration signal (suspension gap signal, acceleration signal) generated by the upper frame is collected by four suspension sensors and transmitted to the corresponding suspension controller. The control board FPGA receives and processes the signal, and transmits the processing result to the DSP for output calculation and Ethernet / CAN network communication. The calculation result is obtained in the DSP module. The suspension controller outputs a PWM fluctuation drive board based on the DSP calculation result, and drives the IGBT to send control current in real time to keep the suspension gap near the rated value at all times, and in this way, the effect of active vibration isolation is achieved.

[0031] When measuring the actual vibration isolation efficiency, vertical acceleration sensors are installed at the key vibration parts of the upper frame and the feet of the lower frame. The relevant vibration data is measured by a data acquisition instrument, and the data is analyzed in the time domain and frequency domain. The vibration isolation efficiency of the magnetic levitation vibration isolation system is evaluated based on commonly used vibration reduction performance evaluation indicators such as vibration reduction coefficient, system equivalent stiffness, frequency domain response, and control margin.

[0032] When the motor keeps running at 30Hz, the acceleration signal is collected for one minute at a sampling frequency of 20000 to analyze the vibration isolation effect. In the low frequency band of 10-315Hz, the vibration isolation effect reaches 19.75dB, and in the full frequency band of 10-10000Hz, the vibration isolation effect reaches 21.67dB.

[0033] When the motor keeps running at 40Hz, the acceleration signal is collected for one minute at a sampling frequency of 20000 to analyze the vibration isolation effect. In the low frequency band of 10-315Hz, the vibration isolation effect reaches 15.26dB, and in the full frequency band of 10-10000Hz, the vibration isolation effect reaches 21.50dB.

[0034] When the motor keeps running at 50Hz, the acceleration signal is collected for one minute at a sampling frequency of 20000 to analyze the vibration isolation effect. In the low frequency band of 10-315Hz, the vibration isolation effect reaches 13.52dB, and in the full frequency band of 10-10000Hz, the vibration isolation effect reaches 20.26dB.

[0035] If the time interval between two suspensions is too long, a rated small current must be output before suspension to check whether the signal communication is normal before suspension.

[0036] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation, characterized in that: It includes a basic structure of a suspension frame, an electromagnet, a suspension controller, a DC power supply cabinet, a suspension vibration sensor, a vibration isolator, and a valve frame. The upper frame and the lower frame in the basic structure of the suspension frame are connected by multiple electromagnets, which are used to introduce actively controlled electromagnetic force between the vibration source and the load to achieve structural support, so that the vibration source and the load are completely out of mechanical contact; each electromagnet is equipped with a suspension vibration sensor, which is used to collect the suspension gap and vertical vibration data of the electromagnet. When the turbine generator unit foundation carries the vibration excitation source, the suspension vibration sensor collects the suspension gap signal and acceleration signal of the electromagnet in real time, and receives, processes and transmits the signal through the control board FPGA chip. The DSP performs real-time current calculation based on the signal given by FPGA, and generates corresponding PWM waves after completing the calculation based on the real-time suspension gap and acceleration signal of the suspension electromagnet, which acts on the drive board to control the on and off of the power switch IGBT, and generates corresponding control current output to the suspension electromagnet for suspension vibration isolation.

2. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 1 is characterized in that: The basic structure of the suspension frame consists of F rails, sleepers, upper frame, lower frame and steam turbine generator set support.

3. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 1 is characterized in that: Two groups of electromagnets are respectively arranged on the left and right sides of the Y direction of the basic structure of the suspension frame, and a suspension controller is used on each side to control the two-point suspension; a group of electromagnets is respectively arranged on the front and rear sides of the X direction, and a suspension controller is used on both sides to control the two-point suspension.

4. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 3 is characterized in that: Each suspension controller has two suspension control boards and realizes hot standby redundancy through life signals. The suspension control circuit of each control board realizes input signal processing and output signal control based on DSP chip and FPGA chip. The FGPA chip processes the monitoring data of each sensor and the DSP chip calculates the control quantity.

5. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 4 is characterized in that: When each suspension controller is working normally, the suspension control board 1 sends a life signal to the suspension control board 2 based on the suspension gap signal and acceleration signal of the corresponding control point monitored by the suspension sensor. At this time, the suspension control board 2 only receives the suspension characteristic signal but does not output it. When the suspension control board 1 fails, the suspension control board 2 cannot receive the life signal given by the suspension control board 1 and takes over the output synchronously; the control output of the control module acts on the drive module to realize the current output in the suspension electromagnet, and the four suspension points float together, controlling the suspension gap to be at the rated value to ensure the stability of the suspension.

6. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 1 is characterized in that: The lower frame and the valve frame are isolated twice by multiple rubber isolators, which together with the magnetic suspension isolation achieve the overall vibration isolation effect of the steam turbine unit.

7. The magnetic suspension frame scaled prototype test platform for steam turbine vibration isolation according to claim 1 is characterized in that: The valve frame is constructed with high-strength, low-weight materials to ensure the rigidity and lightness of the overall structure to adapt to the complex working environment of the ship.

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