Steam turbine generator unit auxiliary machine steam-electric dual drive system and multi-mode intelligent control method thereof

Abstract

The steam and electricity dual drive system for auxiliary machines of a thermal power unit and a multi-mode intelligent control method thereof belong to the field of energy control and comprise a steam drive device, an electricity drive device, an auxiliary machine, a clutch and a control unit. The steam drive device, the electricity drive device and the auxiliary machine are coaxially connected in sequence. The steam drive device and the electricity drive device are connected through the clutch. The control unit is connected with the steam drive device, the electricity drive device and the clutch respectively and is used for coordinating the operation state of the device and switching the working mode of the system. The invention effectively suppresses the oscillation of mode switching at the critical working condition and prevents frequent switching through the mode recognition and hysteresis switching method of generalized power margin. Meanwhile, the invention explicitly models and compensates the mechanical closing delay of the clutch in the synchronous control through the dynamic prediction closed-loop synchronous control method, issues the instruction in advance through the prediction algorithm, so that the actual closing moment reaches the synchronous state.

Description

Technical Field

[0001] This invention belongs to the field of energy control, specifically the steam-electric dual-drive system for auxiliary equipment of thermal power units and its multimodal intelligent control method, which can be widely applied to the steam-electric dual-drive retrofit of thermal power units to improve system flexibility. Background Technology

[0002] With the continuous increase in the penetration rate of new energy sources and the deepening of electricity market transactions, grid load fluctuations are becoming increasingly severe, placing higher demands on the operational flexibility of traditional coal-fired power units. Units need to possess deep peak-shaving capabilities to adapt to wide-load, rapidly changing operating conditions. Against this backdrop, the adaptability of auxiliary systems is particularly prominent: when the unit is operating at low load, steam-driven auxiliary equipment (such as small steam turbines driven by the heating network circulating pump) faces the dilemma of insufficient power, inability to guarantee speed and output due to decreased steam source pressure and flow; while during high-load periods, although steam source power is sufficient, it is necessary to throttle through regulating valves to adapt to the needs of auxiliary equipment, resulting in significant throttling losses and preventing the effective utilization of surplus steam energy.

[0003] Currently, auxiliary equipment in thermal power units mostly adopts a single steam-driven or electric-driven mode, which makes it difficult to achieve a balance between safety, economy and flexibility over a wide load range. In addition, existing dual-drive steam and electric technology still generally suffers from problems such as insufficient flexibility in switching drive modes and the risk of shock during the switching process in practical applications. Summary of the Invention

[0004] This invention provides a dual-drive system for steam and electricity in auxiliary equipment of thermal power units and its multimodal intelligent control method to overcome the deficiencies in the prior art.

[0005] This invention is achieved through the following technical solution: The auxiliary steam-electric dual-drive system of thermal power units includes steam drive equipment, electric drive equipment, auxiliary equipment, clutch, and control unit; The aforementioned steam-driven equipment, electric-driven equipment, and auxiliary equipment are connected coaxially in sequence; The aforementioned vehicle-driven equipment and electric-driven equipment are connected via the aforementioned clutch; The control unit is connected to the gas drive equipment, electric drive equipment and clutch respectively, and is used to coordinate and control the operating status of the equipment and switch the working mode of the system.

[0006] As described above, the auxiliary machine of the thermal power unit is a heat network circulation pump, and the auxiliary machine is driven by steam-driven equipment and / or electric-driven equipment. The aforementioned steam-driven equipment is a steam turbine; The electric drive device is a permanent magnet synchronous motor or a flywheel energy storage motor. The electric drive device is driven and controlled by a frequency converter, and the frequency converter enables bidirectional flow of electrical energy between the device and the power supply system.

[0007] In the above-mentioned auxiliary steam-electric dual-drive system for thermal power units, the frequency converter is a full-power converter; the power supply system is a plant power system, a power grid, or an energy storage system.

[0008] The steam-electric dual-drive system for auxiliary equipment of thermal power units, as described above, has the following operating modes: steam-driven power generation mode, steam-electric coordinated mode, and electric-driven compensation mode.

[0009] A multimodal intelligent control method for a dual-drive steam-electric auxiliary system of a thermal power unit includes the following steps: Step 1: When the auxiliary machine is in the startup phase, enter the electric drive compensation mode, keep the clutch disengaged, the air drive equipment is in an isolated state, and drive the auxiliary machine through the electric drive equipment; Step 2: During the electric drive compensation mode operation phase, real-time system status monitoring and decision-making loop are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from electric drive compensation mode to electric-gasoline co-operation mode are met. Step 3: If the mode switching conditions are not met, return to step 2 and maintain the electric drive compensation mode operation; if the mode switching conditions are met, the steam drive equipment is integrated into the shaft system with zero impact through closed-loop synchronous control based on dynamic prediction, and the system enters the steam-electric coordination mode, keeping the steam valves of the steam drive equipment fully open, and dynamically allocating the power of the steam drive equipment and the electric drive equipment with the goal of meeting the power requirements of the auxiliary machine. Step 4: During the operation phase of the electric-gas co-operation mode, real-time monitoring and decision-making of the system status are carried out to respond to changes in system operating conditions. The target mode is determined by the operation mode identification and hysteresis switching method based on the generalized power margin. Step 5: If the target mode is the steam-driven power generation mode, proceed to step 6; if the target mode is the steam-electric co-generation mode, return to step 4 and maintain the steam-electric co-generation mode operation; if the target mode is the electric drive compensation mode, proceed to step 9. Step 6: When switching from steam-electric co-operation mode to steam-driven generator mode, keep the steam valves of the steam-driven equipment fully open. Under the premise of meeting the power requirements of the auxiliary equipment, control the electric drive equipment to switch from motor operation mode to generator operation mode to convert the excess mechanical energy of the shaft system into electrical energy. Step 7: During the operation phase of the steam-driven power generation mode, real-time monitoring and decision-making loops of the system status are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from the steam-driven power generation mode to the steam-electric co-generation mode are met. Step 8: If the mode switching conditions are not met, return to step 7 and maintain the operation of the steam-driven power generation mode; if the mode switching conditions are met, the system switches from the steam-driven power generation mode to the steam-electric co-operation mode. Under the premise of meeting the power requirements of the auxiliary equipment, the electric drive equipment is controlled to switch from the generator operation mode to the motor operation mode, and the system returns to step 4. Step 9: When the system switches from the steam-electric co-operation mode to the electric drive compensation mode, it first performs power transfer to smoothly transfer all the load to the electric drive equipment, and drives the auxiliary machine to run through the electric drive equipment. After the steam drive equipment is unloaded, the clutch is disengaged and the system returns to step 2. Step 10: When the system receives a shutdown command, if the system is in steam-driven generator mode or steam-electric co-generation mode, it needs to smoothly transfer all the load to the motor first. After the steam-driven equipment is unloaded, it sends a disengagement command to the clutch to control the electric drive equipment to slow down smoothly. If the system is in electric drive compensation mode, the clutch is already in the disengaged state, and the electric drive equipment is controlled to slow down smoothly.

[0010] The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of thermal power units described above includes the following steps in steps 2, 4, and 7: Operation mode identification and hysteresis switching based on generalized power margin. Step 1): Calculate the generalized power margin using the following formula: in, For generalized power margin, This indicates that the gas-powered energy company has a surplus. This indicates insufficient steam power. This represents the maximum output power of the steam-driven equipment under the current steam inlet parameters. For the real-time power requirements of auxiliary equipment; Step 2): Define the hysteresis parameters: This is the hysteresis width, a positive value, which is set comprehensively based on the system's measured noise, the output fluctuation amplitude of the steam-driven equipment, and the allowable switching frequency. The higher the positive threshold value for entering the steam-driven power generation mode, the more the system tends to remain in the steam-electric co-generation mode; the lower the value value, the earlier the system will enter the steam-driven power generation mode. The negative threshold for entering electric drive compensation mode is as follows: the larger the absolute value, the higher the system's tolerance for insufficient steam supply; the smaller the absolute value, the earlier the system switches to electric drive compensation mode. Step 3): Mode hysteresis switching: When the mode is electric drive compensation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the electric drive compensation mode will continue to operate; if the conditions are met, the system will switch to the electric-vehicle co-operation mode. When the mode is co-generation mode, determine the generalized power margin: when When the time comes, switch to steam-driven power generation mode; when At the same time, maintain the operation in the steam-electric coordinated mode; when When the time comes, switch to electric drive compensation mode.

[0011] When the mode is steam-driven power generation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the steam-driven power generation mode will continue to operate; if the conditions are met, the mode will switch to steam-electric co-generation mode.

[0012] The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of thermal power units described above, wherein step 3 of the closed-loop synchronous control method based on dynamic prediction includes the following steps: Step 3-1: In the coarse synchronization stage, the speed is coarsely adjusted to control the speed increase of the steam-driven equipment and track the speed of the electric-driven equipment; conventional closed-loop speed control is used to quickly adjust the speed of the steam-driven equipment to the target range. Step 3-2: In the fine synchronization stage, phase synchronization and speed fine-tuning are performed. After the speed difference is less than the threshold, the phase locking loop and predictive control algorithm are activated to precisely adjust the speed and phase of the steam drive equipment, so that the speed difference and phase difference between the electric drive side shaft system and the steam drive equipment rotor on both sides of the clutch approach zero. Step 3-3: Predict the timing of clutch engagement. Based on the precise synchronization results, select the optimal timing to engage the clutch and ensure zero-impact shaft coupling.

[0013] The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of thermal power units described above includes the following specific steps in step 3-2: Step 3-2-1: Calculate the speed difference in real time. The calculation formula is as follows: in, For the speed difference; This refers to the real-time rotational speed of the side shaft system of the electric drive equipment. This refers to the real-time rotational speed of the rotor in the steam-driven equipment. Step 3-2-2: Calculate the phase difference in real time. The calculation formula is as follows: in, Phase difference; Real-time phase angle of the side shaft system of the electric drive equipment; Real-time phase angle of the rotor of the steam-driven equipment; Step 3-2-3: Calculate the future state based on model prediction. The calculation formula is as follows: in, The current moment; This refers to the mechanical closing delay time of the clutch. for The difference in rotational speed at any given moment; for The difference in rotational speed at any given moment; for Phase difference at any given moment; for Phase difference at any given moment; The angular acceleration of the steam-driven equipment is determined by the control valve command. control; The angular acceleration of the shaft system on the side of the electric drive equipment is controlled by the frequency converter command; Step 3-2-4: Calculate the required acceleration correction, the formula is as follows: in, For acceleration correction parameters; for Phase difference at any given moment; This refers to the mechanical closing delay time of the clutch. , The adjustment coefficient is determined experimentally. Step 3-2-5: Generate and execute control instructions, the formula of which is: in, For control commands; This is the current valve control command for the steam-driven equipment; For acceleration correction parameters; This refers to the acceleration gain coefficient of the small steam turbine. This represents the maximum valve change rate of the steam-driven equipment.

[0014] Step 3-2-6: Check the fine synchronization conditions: Determine if the system state meets the following conditions: and in, for The difference in rotational speed at any given moment; The threshold for the closed rotational speed difference; for Phase difference at any given moment; This is the closed phase difference threshold; If the conditions are not met, repeat the above steps; if the conditions are met, it indicates that the system synchronization is ready.

[0015] The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of thermal power units described above includes the following specific steps in step 3-3: Step 3-3-1: Calculate the closure quality index, the formula of which is: in, To create a closed-loop quality index, the current state is taken into account. , ) and dynamic trends (through ); The standard deviation threshold for the speed difference; The standard deviation threshold for phase difference; This is the adjustment coefficient for the rate of change of speed difference; Step 3-3-2: Select the optimal closing time: Determine whether the following conditions are met: ,in, This is the quality threshold; If the conditions are not met, wait for the next control cycle; if the conditions are met, continuously calculate the quality index Q of the current actual state. When Q exceeds the threshold and continues for several cycles, issue a closing command to the clutch control unit to ensure that the synchronization condition is stable at the moment of closing, avoid false triggering caused by noise measurement in a single cycle, and achieve zero-impact parallel shafting of the air drive equipment.

[0016] The advantages of this invention are: This invention effectively suppresses oscillations during mode switching under critical conditions and prevents frequent switching by using a generalized power margin operation mode identification and hysteresis switching method; simultaneously, this invention uses a dynamic prediction closed-loop synchronization control method to explicitly model and compensate for the mechanical closing delay of the clutch in synchronization control, and issues commands in advance through a prediction algorithm to ensure that the actual closing moment reaches a synchronized state; at the same time, through phase-speed joint prediction, it ensures that both meet the accuracy requirements at the moment of closing, achieving zero-impact parallel shaft operation and improving the stability and safety of the unit operating in a wide load range. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the operation mode identification and hysteresis switching method based on generalized power margin of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The auxiliary steam-electric dual-drive system of thermal power units includes steam drive equipment, electric drive equipment, auxiliary equipment, clutch, and control unit; The aforementioned steam-driven equipment, electric-driven equipment, and auxiliary equipment are connected coaxially in sequence; The aforementioned vehicle-driven equipment and electric-driven equipment are connected via the aforementioned clutch to achieve engagement and disengagement of power transmission; The control unit is connected to the gas drive equipment, electric drive equipment and clutch respectively, and is used to coordinate and control the operating status of the equipment and switch the working mode of the system.

[0021] Specifically, the auxiliary machine described in this embodiment is a heating network circulation pump, which is driven by steam-driven equipment and / or electric-driven equipment, thereby realizing flexible configuration of the operating mode; The aforementioned steam-driven equipment is a steam turbine; The electric drive equipment is a permanent magnet synchronous motor or a flywheel energy storage motor, which has two operating modes: motor and generator. The electric drive equipment is driven and controlled by a frequency converter, and the frequency converter enables bidirectional flow of electrical energy between the electric drive equipment and the power supply system.

[0022] Specifically, the frequency converter described in this embodiment is a full-power converter, which can completely decouple the speed of the permanent magnet synchronous motor from the frequency of the power supply system, enabling the permanent magnet synchronous motor to smoothly adjust its speed across the entire operating range; the power supply system is a plant power system, a power grid, or an energy storage system. When the plant power system or the power grid does not have the capacity to receive power, the energy storage system can effectively store the electrical energy generated by the system.

[0023] Furthermore, the operating modes of this embodiment include steam-driven power generation mode, steam-electric co-generation mode, and electric drive compensation mode.

[0024] A multimodal intelligent control method for a dual-drive steam-electric auxiliary system of a thermal power unit includes the following steps: Step 1: When the auxiliary machine is in the startup phase, enter the electric drive compensation mode, keep the clutch disengaged, the air drive equipment is in an isolated state, and drive the auxiliary machine through the electric drive equipment; Step 2: During the electric drive compensation mode operation phase, real-time system status monitoring and decision-making loop are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from electric drive compensation mode to electric-gasoline co-operation mode are met. Step 3: If the mode switching conditions are not met, return to step 2 and maintain the electric drive compensation mode operation; if the mode switching conditions are met, the steam drive equipment is integrated into the shaft system with zero impact through closed-loop synchronous control based on dynamic prediction, and the system enters the steam-electric coordination mode, keeping the steam valves of the steam drive equipment fully open, and dynamically allocating the power of the steam drive equipment and the electric drive equipment with the goal of meeting the power requirements of the auxiliary machine. Step 4: During the operation phase of the electric-gas co-operation mode, real-time monitoring and decision-making of the system status are carried out to respond to changes in system operating conditions. The target mode is determined by the operation mode identification and hysteresis switching method based on the generalized power margin. Step 5: If the target mode is the steam-driven power generation mode, proceed to step 6; if the target mode is the steam-electric co-generation mode, return to step 4 and maintain the steam-electric co-generation mode operation; if the target mode is the electric drive compensation mode, proceed to step 9. Step 6: When switching from steam-electric co-operation mode to steam-driven generator mode, keep the steam valves of the steam-driven equipment fully open. Under the premise of meeting the power requirements of the auxiliary equipment, control the electric drive equipment to switch from motor operation mode to generator operation mode to convert the excess mechanical energy of the shaft system into electrical energy. Step 7: During the operation phase of the steam-driven power generation mode, real-time monitoring and decision-making loops of the system status are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from the steam-driven power generation mode to the steam-electric co-generation mode are met. Step 8: If the mode switching conditions are not met, return to step 7 and maintain the operation of the steam-driven power generation mode; if the mode switching conditions are met, the system switches from the steam-driven power generation mode to the steam-electric co-operation mode. Under the premise of meeting the power requirements of the auxiliary equipment, the electric drive equipment is controlled to switch from the generator operation mode to the motor operation mode, and the system returns to step 4. Step 9: When the system switches from the steam-electric co-operation mode to the electric drive compensation mode, it first performs power transfer to smoothly transfer all the load to the electric drive equipment, and drives the auxiliary machine to run through the electric drive equipment. After the steam drive equipment is unloaded, the clutch is disengaged and the system returns to step 2. Step 10: When the system receives a shutdown command, if the system is in steam-driven generator mode or steam-electric co-generation mode, it needs to smoothly transfer all the load to the motor first. After the steam-driven equipment is unloaded, it sends a disengagement command to the clutch to control the electric drive equipment to slow down smoothly. If the system is in electric drive compensation mode, the clutch is already in the disengaged state, and the electric drive equipment is controlled to slow down smoothly.

[0025] Specifically, the operation mode identification and hysteresis switching method based on generalized power margin in steps 2, 4, and 7 of this embodiment includes the following steps: Step 1): Calculate the generalized power margin using the following formula: in, For generalized power margin, This indicates that the gas-powered energy company has a surplus. This indicates insufficient steam power. This represents the maximum output power of the steam-driven equipment under the current steam inlet parameters. For the real-time power requirements of auxiliary equipment; Step 2): Define the hysteresis parameters: This is the hysteresis width, a positive value, which is set comprehensively based on the system's measured noise, the output fluctuation amplitude of the steam-driven equipment, and the allowable switching frequency. The higher the positive threshold value for entering the steam-driven power generation mode, the more the system tends to remain in the steam-electric co-generation mode; the lower the value value, the earlier the system will enter the steam-driven power generation mode. The negative threshold for entering electric drive compensation mode is as follows: the larger the absolute value, the higher the system's tolerance for insufficient steam supply; the smaller the absolute value, the earlier the system switches to electric drive compensation mode. Step 3): Mode hysteresis switching: When the mode is electric drive compensation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the electric drive compensation mode will continue to operate; if the conditions are met, the system will switch to the electric-vehicle co-operation mode. When the mode is co-generation mode, determine the generalized power margin: when When the time comes, switch to steam-driven power generation mode; when At the same time, maintain the operation in the steam-electric coordinated mode; when When the time comes, switch to electric drive compensation mode.

[0026] When the mode is steam-driven power generation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the steam-driven power generation mode will continue to operate; if the conditions are met, the mode will switch to steam-electric co-generation mode.

[0027] Specifically, the closed-loop synchronization control method based on dynamic prediction in step 3 of this embodiment includes the following steps: Step 3-1: In the coarse synchronization stage, perform coarse speed adjustment, control the speed increase of the steam-driven equipment to track the speed of the electric-driven equipment; use conventional closed-loop speed control (such as PID control) to quickly adjust the speed of the steam-driven equipment to the target range (such as the target speed). That is, the speed of the electric drive equipment ); Step 3-2: In the fine synchronization stage, phase synchronization and speed fine-tuning are performed. After the speed difference is less than a threshold (e.g., 10 rpm), the phase-locked loop and predictive control algorithm are activated to precisely adjust the speed and phase of the gas drive equipment, so that the speed difference and phase difference between the electric drive side shaft system on both sides of the clutch and the speed difference and phase difference between the gas drive equipment rotor approach zero. Step 3-3: Predict the timing of clutch engagement. Based on the precise synchronization results, select the optimal timing to engage the clutch and ensure zero-impact shaft coupling.

[0028] Furthermore, the specific operation of step 3-2 in this embodiment includes the following steps: Step 3-2-1: Calculate the speed difference in real time. The calculation formula is as follows: in, For the speed difference; This refers to the real-time rotational speed of the side shaft system of the electric drive equipment. This refers to the real-time rotational speed of the rotor in the steam-driven equipment. Step 3-2-2: Calculate the phase difference in real time. The calculation formula is as follows: in, Phase difference; Real-time phase angle of the side shaft system of the electric drive equipment; Real-time phase angle of the rotor of the steam-driven equipment; Step 3-2-3: Calculate the future state based on model prediction. The calculation formula is as follows: in, The current moment; This refers to the mechanical closing delay time of the clutch. for The difference in rotational speed at any given moment; for The difference in rotational speed at any given moment; for Phase difference at any given moment; for Phase difference at any given moment; The angular acceleration of the steam-driven equipment is determined by the control valve command. control; The angular acceleration of the shaft system on the side of the electric drive equipment is controlled by the frequency converter command; Step 3-2-4: Calculate the required acceleration correction, the formula is as follows: in, For acceleration correction parameters; for Phase difference at any given moment; This refers to the mechanical closing delay time of the clutch. , The adjustment coefficient is determined experimentally. Step 3-2-5: Generate and execute control instructions, the formula of which is: in, For control commands; This is the current valve control command for the steam-driven equipment; For acceleration correction parameters; This refers to the acceleration gain coefficient of the small steam turbine. This represents the maximum valve change rate of the steam-driven equipment.

[0029] Step 3-2-6: Check the fine synchronization conditions: Determine if the system state meets the following conditions: and in, for The difference in rotational speed at any given moment; The threshold for the closed rotational speed difference; for Phase difference at any given moment; This is the closed phase difference threshold; If the conditions are not met, repeat the above steps; if the conditions are met, it indicates that the system synchronization is ready.

[0030] Furthermore, the specific operation of step 3-3 in this embodiment includes the following steps: Step 3-3-1: Calculate the closure quality index, the formula of which is: in, To create a closed-loop quality index, the current state is taken into account. , ) and dynamic trends (through ); The standard deviation threshold for the speed difference; The standard deviation threshold for phase difference; This is the adjustment coefficient for the rate of change of speed difference; Step 3-3-2: Select the optimal closing time: Determine whether the following conditions are met: ,in, This is the quality threshold; If the conditions are not met, wait for the next control cycle; if the conditions are met, continuously calculate the quality index Q of the current actual state. When Q exceeds the threshold and continues for several cycles (e.g., 3 control cycles), issue a closing command to the clutch control unit to ensure that the synchronization condition is stable at the moment of closing, avoid false triggering caused by noise in a single cycle, and achieve zero-impact parallel shafting of the gas drive equipment.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-drive steam-electric system for auxiliary equipment of a thermal power unit, characterized in that: This includes vehicle-driven equipment, electric-driven equipment, auxiliary machinery, clutches, and control units; The aforementioned steam-driven equipment, electric-driven equipment, and auxiliary equipment are connected coaxially in sequence; The aforementioned vehicle-driven equipment and electric-driven equipment are connected via the aforementioned clutch; The control unit is connected to the gas drive equipment, electric drive equipment and clutch respectively, and is used to coordinate and control the operating status of the equipment and switch the working mode of the system.

2. The auxiliary steam-electric dual-drive system for thermal power units according to claim 1, characterized in that: The auxiliary machine is a heating network circulation pump, which is driven by steam-driven equipment and / or electric-driven equipment; The aforementioned steam-driven equipment is a steam turbine; The electric drive device is a permanent magnet synchronous motor or a flywheel energy storage motor. The electric drive device is driven and controlled by a frequency converter, and the frequency converter enables bidirectional flow of electrical energy between the device and the power supply system.

3. The auxiliary steam-electric dual-drive system for thermal power units according to claim 1, characterized in that: The frequency converter is a full-power converter; the power supply system is a plant power system, a power grid, or an energy storage system.

4. The auxiliary steam-electric dual-drive system for thermal power units according to claim 1, characterized in that: Its operating modes include steam-driven power generation mode, steam-electric co-generation mode, and electric drive compensation mode.

5. A multi-modal intelligent control method for a dual-drive steam-electric auxiliary system of a thermal power unit, characterized in that: Includes the following steps: Step 1: When the auxiliary machine is in the startup phase, enter the electric drive compensation mode, keep the clutch disengaged, the air drive equipment is in an isolated state, and drive the auxiliary machine through the electric drive equipment; Step 2: During the electric drive compensation mode operation phase, real-time system status monitoring and decision-making loop are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from electric drive compensation mode to electric-gasoline co-operation mode are met. Step 3: If the mode switching conditions are not met, return to step 2 and maintain the electric drive compensation mode operation; if the mode switching conditions are met, the steam drive equipment is integrated into the shaft system with zero impact through closed-loop synchronous control based on dynamic prediction, and the system enters the steam-electric coordination mode, keeping the steam valves of the steam drive equipment fully open, and dynamically allocating the power of the steam drive equipment and the electric drive equipment with the goal of meeting the power requirements of the auxiliary machine. Step 4: During the operation phase of the electric-gas co-operation mode, real-time monitoring and decision-making of the system status are carried out to respond to changes in system operating conditions. The target mode is determined by the operation mode identification and hysteresis switching method based on the generalized power margin. Step 5: If the target mode is the steam-driven power generation mode, proceed to step 6; if the target mode is the steam-electric co-generation mode, return to step 4 and maintain the steam-electric co-generation mode operation; if the target mode is the electric drive compensation mode, proceed to step 9. Step 6: When switching from steam-electric co-operation mode to steam-driven generator mode, keep the steam valves of the steam-driven equipment fully open. Under the premise of meeting the power requirements of the auxiliary equipment, control the electric drive equipment to switch from motor operation mode to generator operation mode to convert the excess mechanical energy of the shaft system into electrical energy. Step 7: During the operation phase of the steam-driven power generation mode, real-time monitoring and decision-making loops of the system status are performed. The operation mode identification and hysteresis switching method based on generalized power margin are used to determine whether the conditions for switching from the steam-driven power generation mode to the steam-electric co-generation mode are met. Step 8: If the mode switching conditions are not met, return to step 7 and maintain the operation of the steam-driven power generation mode; if the mode switching conditions are met, the system switches from the steam-driven power generation mode to the steam-electric co-operation mode. Under the premise of meeting the power requirements of the auxiliary equipment, the electric drive equipment is controlled to switch from the generator operation mode to the motor operation mode, and the system returns to step 4. Step 9: When the system switches from the steam-electric co-operation mode to the electric drive compensation mode, it first performs power transfer to smoothly transfer all the load to the electric drive equipment, and drives the auxiliary machine to run through the electric drive equipment. After the steam drive equipment is unloaded, the clutch is disengaged and the system returns to step 2. Step 10: When the system receives a shutdown command, if the system is in steam-driven generator mode or steam-electric co-generation mode, it needs to smoothly transfer all the load to the motor first. After the steam-driven equipment is unloaded, it sends a disengagement command to the clutch to control the electric drive equipment to slow down smoothly. If the system is in electric drive compensation mode, the clutch is already in the disengaged state, and the electric drive equipment is controlled to slow down smoothly.

6. The multi-modal intelligent control method for the steam-electric dual-drive system of auxiliary power units according to claim 1, characterized in that: The operation mode identification and hysteresis switching method based on generalized power margin in steps 2, 4, and 7 includes the following steps: Step 1): Calculate the generalized power margin using the following formula: in, For generalized power margin, This indicates that the gas-powered energy company has a surplus. This indicates insufficient steam power. This represents the maximum output power of the steam-driven equipment under the current steam inlet parameters. For the real-time power requirements of auxiliary equipment; Step 2): Define the hysteresis parameters: This is the hysteresis width, a positive value, which is set comprehensively based on the system's measured noise, the output fluctuation amplitude of the steam-driven equipment, and the allowable switching frequency. The higher the positive threshold value for entering the steam-driven power generation mode, the more the system tends to remain in the steam-electric co-generation mode; the lower the value value, the earlier the system will enter the steam-driven power generation mode. The negative threshold for entering electric drive compensation mode is as follows: the larger the absolute value, the higher the system's tolerance for insufficient steam supply; the smaller the absolute value, the earlier the system switches to electric drive compensation mode. Step 3): Mode hysteresis switching: When the mode is electric drive compensation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the electric drive compensation mode will continue to operate; if the conditions are met, the system will switch to the electric-vehicle co-operation mode. When the mode is co-generation mode, determine the generalized power margin: when When the time comes, switch to steam-driven power generation mode; when At the same time, maintain the operation in the steam-electric coordinated mode; when When switching to electric drive compensation mode; When the mode is steam-driven power generation mode, determine whether the generalized power margin meets the following conditions: If the conditions are not met, the steam-driven power generation mode will continue to operate; if the conditions are met, the mode will switch to steam-electric co-generation mode.

7. The multi-modal intelligent control method for the auxiliary steam-electric dual-drive system of a thermal power unit according to claim 1, characterized in that: The closed-loop synchronization control method based on dynamic prediction in step 3 includes the following steps: Step 3-1: In the coarse synchronization stage, the speed is coarsely adjusted to control the speed increase of the steam-driven equipment and track the speed of the electric-driven equipment; conventional closed-loop speed control is used to quickly adjust the speed of the steam-driven equipment to the target range. Step 3-2: In the fine synchronization stage, phase synchronization and speed fine-tuning are performed. After the speed difference is less than the threshold, the phase-locked loop and predictive control algorithm are activated to precisely adjust the speed and phase of the steam drive equipment, so that the speed difference and phase difference between the electric drive side shaft system speed and the steam drive equipment rotor on both sides of the clutch approach the threshold. zero: Step 3-3: Predict the timing of clutch engagement. Based on the precise synchronization results, select the optimal timing to engage the clutch and ensure zero-impact shaft coupling.

8. The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of thermal power units according to claim 7, characterized in that: The specific operation of step 3-2 includes the following steps: Step 3-2-1: Calculate the speed difference in real time. The calculation formula is as follows: in, For the speed difference; This refers to the real-time rotational speed of the side shaft system of the electric drive equipment. This refers to the real-time rotational speed of the rotor in the steam-driven equipment. Step 3-2-2: Calculate the phase difference in real time. The calculation formula is as follows: in, Phase difference; Real-time phase angle of the side shaft system of the electric drive equipment; Real-time phase angle of the rotor of the steam-driven equipment; Step 3-2-3: Calculate the future state based on model prediction. The calculation formula is as follows: in, The current moment; This refers to the mechanical closing delay time of the clutch. for The difference in rotational speed at any given moment; for The difference in rotational speed at any given moment; for Phase difference at any given moment; for Phase difference at any given moment; The angular acceleration of the steam-driven equipment is determined by the control valve command. control; The angular acceleration of the shaft system on the side of the electric drive equipment is controlled by the frequency converter command; Step 3-2-4: Calculate the required acceleration correction, the formula is as follows: in, For acceleration correction parameters; for Phase difference at any given moment; This refers to the mechanical closing delay time of the clutch. , The adjustment coefficient is determined experimentally. Step 3-2-5: Generate and execute control instructions, the formula of which is: in, For control commands; This is the current valve control command for the steam-driven equipment; For acceleration correction parameters; This refers to the acceleration gain coefficient of the small steam turbine. This represents the maximum valve variation rate of the steam-driven equipment. Step 3-2-6: Check the fine synchronization conditions: Determine if the system state meets the following conditions: and in, for The difference in rotational speed at any given moment; The threshold for the closed rotational speed difference; for Phase difference at any given moment; This is the closed phase difference threshold; If the conditions are not met, repeat the above steps; if the conditions are met, it indicates that the system synchronization is ready.

9. The multimodal intelligent control method for the auxiliary steam-electric dual-drive system of a thermal power unit according to claim 7, characterized in that: The specific operations of step 3-3 include the following steps: Step 3-3-1: Calculate the closure quality index, the formula of which is: in, To establish a closed-loop quality index, both the current status and dynamic trends must be considered. The standard deviation threshold for the speed difference; The standard deviation threshold for phase difference; This is the adjustment coefficient for the rate of change of speed difference; Step 3-3-2: Select the optimal closing time: Determine if the following conditions are met: ,in, This is the quality threshold; If the conditions are not met, wait for the next control cycle; if the conditions are met, continuously calculate the quality index Q of the current actual state. When Q exceeds the threshold and continues for several cycles, issue a closing command to the clutch control unit to ensure that the synchronization condition is stable at the moment of closing, avoid false triggering caused by noise measurement in a single cycle, and achieve zero-impact parallel shafting of the air drive equipment.

Images