Low-noise variable speed constant pressure speed control system

Abstract

The present invention relates to a low-noise variable speed constant pressure speed regulation system. The hydraulic oil station tank of the hydraulic oil station is equipped with two small integrated accumulators, two servo motors and an oil pump. The oil inlet of the oil pump is connected to the filter in the hydraulic oil station tank, and the oil outlet of the oil pump is connected to the oil station outlet component installed on the side of the hydraulic oil station tank. The oil station outlet component is connected to the accumulator, and the servo motor is connected to the oil pump. The oil pump is a low-noise electric oil pump, which is driven by the servo motor to reduce the influence of the electric oil pump on the vibration noise of the unit; the servo motor is connected to the intelligent motion control board, and the intelligent motion control board is connected to the measuring instrument on the oil station outlet component. The intelligent motion control board controls the speed of the servo motor to maintain the output oil pressure of the hydraulic oil station at a set value, and monitors the oil pressure value of the hydraulic oil station in real time through the measuring instrument to optimize the oil pressure endurance, reduce the start and stop frequency of the electric oil pump, and reduce the on state time.

Description

Technical Field

[0001] The present invention relates to a speed control system for a steam turbine generator set, in particular to a low-noise variable speed constant voltage speed control system. Background Art

[0002] The speed control system impacts the operational stability, safety, and reliability of a steam turbine generator set and is a crucial component of the system. It primarily consists of a high-pressure oil motor, a hydraulic oil station, oil station outlet components, an oil pump, a motor, an accumulator, and measuring instruments. The hydraulic oil station, serving as the oil supply unit for the high-pressure oil motor, is a crucial component of the speed control system. It provides hydraulic oil at a pressure of 7 to 16 MPa, adjustable pressure, and adapts to ambient temperatures of 5 to 70°C. The hydraulic oil station utilizes an electric motor to drive the pump, which operates continuously to supply hydraulic oil to the unit's high-pressure oil supply units.

[0003] The existing hydraulic oil stations for steam turbine generator sets are mainly of the following two types:

[0004] The first is a low-voltage electro-hydraulic speed control system, such as Figure 1 As shown in the figure, the oil pressure is regulated solely as power oil. Because it is derived from the power oil, generated by the turbine's electric oil pump and the turbine's internal oil pump, changes in speed generate oil pressure pulses and fluctuations of approximately 1 MPa. The system's mechanical hydraulic mechanism is relatively simple and requires high machining precision. Because forward pressure and power correction are implemented using electrical signals, the number of components is significantly reduced. Furthermore, speed control is implemented using software, simplifying the mechanical structure while enabling more complex functions and shortening the manufacturing and commissioning cycles.

[0005] The second type is a constant speed and constant pressure high voltage electro-hydraulic speed control system, such as Figure 2 As shown. Its regulated oil pressure is only used as power oil. The hydraulic oil station is the oil supply unit of the oil motor, which can provide 9-16MPa hydraulic oil with adjustable pressure. The hydraulic oil station can adapt to an ambient temperature of 5-60°C. The hydraulic oil station uses an electric motor to drive the pump, which works continuously to provide hydraulic oil for the high-pressure oil unit of the unit. The motor adopts ABB M2BAX series products, and the oil station oil pump adopts Eaton PVQ series products. A relief valve is set at the pump outlet of the oil station. When the system pressure exceeds 14MPa, the relief valve opens to serve as overpressure protection. The mechanical hydraulic part of the high-pressure electro-hydraulic speed control system eliminates the throttle and only retains the oil motor, so its structure is further simplified.

[0006] However, the above speed control system still has some drawbacks, mainly including:

[0007] 1. Using a low-voltage electro-hydraulic speed control system, the oil pressure adjustment is easily affected by oil pressure pulses, causing oil pressure fluctuations and unstable factors in the speed control system.

[0008] Second, the constant-speed, constant-pressure, high-voltage electro-hydraulic speed control system uses a motor-driven pump. This pump operates continuously, and the motor pump structure causes vibration and noise, a significant noise source for the unit, affecting the unit's vibration and noise performance. Furthermore, the motor itself consumes a lot of power, making energy conservation less than ideal.

[0009] Therefore, the aforementioned speed control system, as the main form of current steam turbine generator sets, still needs a lot of optimization and adjustment. An advanced speed control system with a small integrated design and low noise design is an important requirement for steam turbine generator sets. Summary of the Invention

[0010] The present invention aims to provide a low-noise variable speed constant voltage speed control system, which realizes a small integrated design of the speed control system, a low-noise design, good energy-saving effect, humanized operation, and an excellent human-computer interaction interface, thereby improving the operating stability and safety and reliability of the steam turbine generator set.

[0011] To achieve the above-mentioned purpose, the technical solution of the present invention is: a low-noise variable speed constant pressure speed control system, comprising a high-pressure oil motor, a hydraulic oil station, an oil station outlet component, an oil pump, a servo motor, an accumulator, and a measuring instrument. The hydraulic oil station tank of the hydraulic oil station is equipped with two small integrated accumulators, two servo motors and an oil pump. The oil inlet of the oil pump is connected to the filter in the hydraulic oil station tank, and the oil outlet of the oil pump is connected to the oil station outlet component installed on the side of the hydraulic oil station tank. The oil station outlet component is connected to the accumulator, so that the pressure oil coming out of the oil pump outlet enters through the oil station outlet component. Accumulator, that is, filling the accumulator with oil; the servo motor is connected to the oil pump, and the oil pump is a low-noise electric oil pump. The low-noise electric oil pump is driven by the servo motor, which can reduce the impact of the electric oil pump on the vibration noise of the unit; the servo motor is connected to the intelligent motion control board, and the intelligent motion control board is connected to the measuring instrument on the oil station outlet component. The intelligent motion control board controls the speed of the servo motor to maintain the output oil pressure of the hydraulic oil station at the set value, and monitors the oil pressure value of the hydraulic oil station in real time through the measuring instrument to optimize the oil pressure endurance, reduce the start and stop frequency of the electric oil pump and reduce the on-state time.

[0012] Furthermore, the intelligent motion control board is connected to the oil tank level detection module in the hydraulic oil station tank, which is used to detect the oil tank level in the hydraulic oil station tank. When the liquid level is detected to be low or the regulated oil pressure is low, the servo motor is shut down for protection, which can avoid overheating and burning of the servo motor during no-load operation.

[0013] Furthermore, the variable speed constant pressure high-voltage electro-hydraulic speed control system is a closed-loop control system. The intelligent motion control board serves as a controller to drive the servo motor to work. The controller collects the servo motor speed through the encoder and the pressure sensor to collect and adjust the oil pressure, and analyzes the servo motor speed and oil pressure data fed back by the encoder and pressure sensor. It adopts fuzzy PID algorithm control to drive the servo motor and keep the oil pressure of the hydraulic oil station constant by controlling the speed of the servo motor.

[0014] Furthermore, the intelligent motion control board serves as the core of the servo motor speed control system and controls the servo motor by analog command input. The speed command input range of the servo motor driver is -10 to 10V, representing a speed command of -n to nr / min.

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

[0016] The present invention realizes a small integrated design of the speed regulation system, a low noise design, good energy-saving effect, a humanized operation mode, and an excellent human-computer interaction interface, thereby improving the operating stability and safety and reliability of the steam turbine generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of an existing low-voltage electro-hydraulic speed regulator;

[0018] Figure 2 This is a schematic diagram of an existing high-voltage electro-hydraulic speed control system;

[0019] Figure 3 Schematic diagram of the variable speed constant pressure high-voltage electro-hydraulic speed control system of the present invention;

[0020] Figure 4 This is the block diagram of the servo control principle of the high-pressure oil motor;

[0021] Figure 5 This is the structure diagram of the fuzzy-PID controller. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 3 The figure shows a low-noise variable speed constant pressure speed control system, which includes a high-pressure oil motor, a hydraulic oil station, an oil station outlet assembly 4, a servo motor 3 and an oil pump, an accumulator 2, and measuring instruments. The hydraulic oil station's oil tank 1 is equipped with two accumulators 2, two servo motors 3, and an oil pump. The servo motors 3 are connected to the oil pumps, the oil pump inlets are connected to the filters in the hydraulic oil station tank, and the oil pump outlets are connected to the oil station outlet assembly 4 mounted on the side of the hydraulic oil station tank. The oil station outlet assembly 4 is connected to the accumulator 2.

[0024] This system is the first to integrate the hydraulic oil station tank 1 and accumulator 2 into a small-scale design. The hydraulic oil station uses a servo motor 3 and a low-noise design of the electric oil pump to minimize the impact of the electric oil pump on the vibration and noise of the unit. At the same time, the oil pressure endurance of the speed control system is optimized to reduce the start and stop frequency of the electric oil pump and shorten the on-state time.

[0025] The speed control system's servo motor 3 utilizes an intelligent motion control board, which maintains the hydraulic station's oil pressure at a set value, supports oil pressure regulation, and monitors the hydraulic station's oil pressure in real time. The servo motor's driver consumes relatively little power, and the STM32-based motion control card is a low-power device, resulting in excellent energy savings. Furthermore, the servo motor's low operating noise, combined with the motor's inherent sound insulation, ensures the system exhibits remarkable low-noise performance. The motion control board includes a tank level detection module that monitors the hydraulic station's tank level. When the level is low or the regulated oil pressure is low, the system shuts down to prevent overheating and motor burnout during no-load operation. The user-friendly operation provides an excellent human-machine interface.

[0026] This speed control system utilizes a closed-loop control system, employing a motion control board as the controller to drive servo motor 3. An encoder measures motor speed, while a pressure sensor collects and adjusts oil pressure. Feedback speed and pressure data are analyzed and then controlled using a fuzzy PID algorithm to drive the servo motor. This speed control maintains constant oil pressure in the hydraulic station by controlling the servo motor's speed. The motion control board, the core of the servo motor speed control system, controls the servo motor via analog command input. The servo motor driver's speed command input range is -10 to 10V, representing a speed command of -n to nr / min.

[0027] In summary, by adopting a variable speed constant pressure high-voltage electro-hydraulic speed control system, the adjustment accuracy and speed of the speed control system are further improved, while the impact of the electric oil pump on the vibration and noise of the unit is minimized. The electro-hydraulic servo valve receives the control command and drives the oil cylinder piston to move, thereby driving the steam valve opening to change. The high-pressure oil motor servo control principle block diagram is as follows: Figure 4 As shown in the figure, when the load increases, the DEH issues a command to open the control valve or increase the load. After calculation and comparison, it outputs a positive bias signal, which acts on the electro-hydraulic servo valve, actuating the high-pressure hydraulic motor and opening the control valve. At this time, the hydraulic motor displacement is fed back to the DEH via the LVDT for comparison. When the bias reaches zero, the control valve stops moving and remains in its new operating position. When the load decreases, the process is reversed.

[0028] The hydraulic oil station, serving as the oil supply unit for the high-pressure hydraulic motor, is a crucial component of the speed control system. It stores and processes hydraulic oil. By controlling the servo motor's speed, an electric oil pump pressurizes the lubricating oil within the station, providing the necessary working medium (hydraulic oil) for the high-pressure hydraulic motor. The system is equipped with two units, one of which serves as a backup. If pump 1 fails, pump 2 takes over. If system oil pressure or flow is insufficient, both pumps operate simultaneously. After the pumps start (maximum flow rate is approximately 7 L / min), they draw hydraulic oil from the hydraulic oil station through the suction filter. The pressurized oil coming out of the oil pump passes through the oil station outlet components (stop valve, one-way valve, oil filter, and overflow valve) and enters the accumulator, which means that the accumulator is filled with oil. During the oil filling process, the system flow will gradually decrease and the oil pressure will begin to rise. When the oil pressure rises above the set system working pressure, the driver controls the servo motor to decelerate and adjust the oil pressure to decrease. When the oil pressure is lower than the set system working pressure, the driver controls the servo motor to increase speed and adjust the oil pressure to increase. Finally, the servo motor's speed control is used to ensure the stability of the regulated oil pressure.

[0029] In terms of the control strategy for regulating the oil pressure of the regulating system, the PID control and fuzzy control methods are combined to form a complementary fuzzy-PID controller that has the advantages of both control methods. Figure 5 shown.

[0030] This system achieves high efficiency, low noise and energy saving effects by adopting a variable speed constant pressure high-voltage electro-hydraulic speed control method. At the same time, it further improves the adjustment accuracy and speed of the speed control system, and obtains better static and dynamic speed control characteristics.

Claims

1. A low-noise variable speed constant pressure speed control system, comprising a high-pressure oil motor, a hydraulic oil station, an oil station outlet assembly, an oil pump, a servo motor, an accumulator, and a measuring instrument, characterized in that: The hydraulic oil station tank of the hydraulic oil station is equipped with two small integrated accumulators, two servo motors and an oil pump. The oil inlet of the oil pump is connected to the filter in the hydraulic oil station tank, and the oil outlet of the oil pump is connected to the oil station outlet component installed on the side of the hydraulic oil station tank. The oil station outlet component is connected to the accumulator so that the pressure oil from the oil pump outlet enters the accumulator through the oil station outlet component, that is, the accumulator is filled with oil; the servo motor is connected to the oil pump, and the oil pump is a low-noise electric oil pump. The low-noise electric oil pump is driven by the servo motor, which can reduce the impact of the electric oil pump on the vibration and noise of the unit; The servo motor is connected to an intelligent motion control board, which is connected to a measuring instrument on an oil station outlet assembly. The intelligent motion control board controls the speed of the servo motor to maintain the output oil pressure of the hydraulic oil station at a set value, and monitors the oil pressure value of the hydraulic oil station in real time through a measuring instrument to optimize the oil pressure endurance, reduce the start-stop frequency of the electric oil pump, and reduce the on-state time. The low-noise variable speed constant pressure speed regulation system is a closed-loop control system. The intelligent motion control board serves as a controller to drive the servo motor to work. The controller collects the servo motor speed and the pressure sensor to adjust the oil pressure, and analyzes the servo motor speed and oil pressure data fed back by the encoder and pressure sensor. It adopts a fuzzy PID algorithm to control and drive the servo motor, and controls the speed of the servo motor to maintain a constant oil pressure in the hydraulic oil station. The intelligent motion control board is connected to an oil tank level detection module in the hydraulic oil station tank, which is used to detect the oil tank level in the hydraulic oil station tank. When the liquid level is detected to be low or the oil pressure is adjusted to be low, the servo motor is shut down for protection, which can avoid overheating and burning of the servo motor during no-load operation.

2. The low-noise variable speed constant voltage speed regulation system according to claim 1 is characterized in that: The intelligent motion control board serves as the core of the servo motor speed control system and controls the servo motor through analog command input. The speed command input range of the servo motor driver is -10~10V, representing a speed command of -n~nr / min.

Images