Hybrid energy storage and thermal power generating unit combined power generation control system

Abstract

The invention provides a hybrid energy storage and thermal power generating unit combined power generation control system, which comprises a data acquisition unit, a calculation unit, a controlled unit, a coordination control unit, a rapid control unit and an execution unit, the calculation unit calculates key thermal parameters and key electrical parameters according to the operation parameters, the coordination control unit and the rapid control unit control the controlled unit according to the key thermal parameters and the key electrical parameters correspondingly, and an energy storage thermal control unit in the controlled unit can respond to a control instruction and conduct precise temperature control on primary / secondary air. The problem of unstable combustion caused by coal quality fluctuation under a low-load working condition is solved, flywheel energy storage is introduced, the frequency modulation qualification rate of the system can be improved, meanwhile, steam heating and electric heating proportions are automatically distributed, the heat storage cost can be reduced, and improvement of the combustion efficiency, wide-load operation and quick start of a thermal power generating unit are achieved. And the overall efficiency and the network source coordination performance of the combined power generation system are improved.

Description

Technical Field

[0001] This invention relates to the field of power generation control technology, and in particular to a hybrid energy storage and thermal power unit combined power generation control system. Background Technology

[0002] Thermal power units, as the core support of traditional power systems, play a crucial role in ensuring power supply stability and baseload security. They convert chemical energy into thermal energy by burning fuel (such as coal) in boilers, which then drives a steam turbine through a steam-water cycle, ultimately converting mechanical energy into electrical energy. However, with the high proportion of new energy sources integrated into the grid and the profound transformation of the power system, thermal power units face multiple challenges, including improved flexibility, rapid response, fuel adaptation, energy storage coordination, and waste heat utilization. 1. The contradiction between flexibility and efficiency in thermal power units is becoming increasingly prominent. In power systems with a high proportion of renewable energy integration, thermal power units need to undertake deep peak shaving and rapid frequency regulation tasks. However, traditional unit designs aim for high-efficiency operation under rated conditions, which leads to problems such as decreased combustion stability and reduced thermal efficiency when operating under wide loads. Especially when the load factor is below 40%, the boiler's stable combustion capability deteriorates sharply, forcing the injection of oil-assisted combustion, which increases operating costs. At the same time, frequent load changes exacerbate equipment fatigue wear. How to overcome the inherent limitations of the units and achieve safe, economical, and wide-load operation has become a common challenge in the industry.

[0003] 2. The inertia of the thermal system limits its rapid response capability. Thermal power units exhibit minute-level lag in responding to grid commands, and the large inertia of key parameters such as main steam pressure limits the power regulation rate. Traditional methods relying on boiler fuel regulation are insufficient to meet dynamic performance requirements when dealing with second-level frequency fluctuations (such as primary frequency regulation) or suppressing power oscillations. Especially in scenarios with a high proportion of renewable energy, the system's equivalent inertia continuously decreases, necessitating external means to compensate for the dynamic response shortcomings of thermal power units. However, existing solutions mostly remain at the level of simple power superposition, failing to address the coordination issue between thermal parameters and electrical control.

[0004] 3. Fluctuations in fuel characteristics increase control complexity. The actual coal quality fed into coal-fired power plants varies significantly in time and space. Fluctuations in parameters such as moisture, ash, and volatile matter directly affect combustion efficiency and pollutant generation. Traditional control strategies rely on a "design coal type" benchmark or offline coal quality analysis lagging several hours, which cannot adapt to changing coal quality conditions in real time. Especially during low-load periods, low-quality coal is prone to risks such as flameout and coking. Existing air and temperature control lacks a dynamic coupling mechanism with coal quality parameters, limiting the safe operating boundaries of the unit.

[0005] 4. Single energy storage technologies are difficult to match the demands across multiple time scales. Although energy storage systems have been introduced to improve the flexibility of thermal power plants, power-type energy storage such as flywheels and batteries are limited by their short duration and cannot support long-term peak shaving; energy-type energy storage such as molten salt, while having large capacity, suffers from insufficient response speed (on the order of seconds). Simply paralleling multiple energy storage systems can easily lead to conflicting control objectives. For example, high-frequency frequency regulation tasks may excessively consume the energy storage's state of charge (SOC), affecting subsequent peak shaving capabilities. Currently, there is a lack of a unified framework for multi-timescale coordinated control mechanisms, making it difficult to simultaneously achieve second-level frequency regulation, minute-level peak shaving, and hourly economic optimization.

[0006] 5. Waste heat utilization and grid support functions are not yet coordinated. Existing thermal power coupled with energy storage systems mostly focus on "valley filling" (storing excess electrical energy) or "peak shaving" (discharge power replenishment), failing to deeply explore the value of energy storage in improving the performance of the generating units themselves. For example, the needs for waste heat recovery during unit start-up and shutdown, heat replenishment for stable combustion under low load, and thermoelectric decoupling during load changes have not yet been linked with the needs of grid ancillary services. This functional disconnect results in limited improvement in the overall energy efficiency of the system and a longer investment payback period. Summary of the Invention

[0007] In view of this, the present invention proposes a hybrid energy storage and thermal power unit combined power generation control system to solve the problems mentioned in the background art.

[0008] The technical solution of this invention is implemented as follows: A hybrid energy storage and thermal power unit combined power generation control system is applied to a power generation system comprising a thermal power unit, two-stage dual-heat source molten salt energy storage, and flywheel energy storage, including: The data acquisition unit is used to collect the operating parameters of the power generation system, including grid frequency, unit active power, main steam pressure, molten salt temperature, molten salt flow rate and flywheel speed. The calculation unit is used to calculate key thermal parameters and key electrical parameters based on operating parameters. The key thermal parameters include the predicted value of main steam pressure, stratified coal quality, and total fuel heat input to the boiler. The key electrical parameters include the predicted value of grid frequency deviation, the current value of grid frequency, the output power of the thermal power unit generator, the instantaneous distribution disturbance power of the thermal power unit generator, and the hybrid energy storage power. Controlled units, used to respond to control commands, include thermal power unit control units, flywheel energy storage control units, molten salt thermal control units and molten salt electrical control units for two-stage dual-heat-source molten salt energy storage; The coordination and control unit is used to generate control commands for the coordinated control of the thermal power unit control unit, the flywheel energy storage control unit, the molten salt thermal control unit and the molten salt electrical control unit of the two-stage dual heat source molten salt energy storage based on key thermal parameters. A rapid control unit is used to generate control commands for the flywheel energy storage control unit and the molten salt electrical control unit based on key electrical parameters; The execution unit is used to execute the response control commands issued by the molten salt thermal control unit, including the secondary air stratified heating unit, water temperature enhancement unit, flue gas temperature enhancement unit, main steam compensation unit, and primary air heating unit; The computing unit is connected to the data acquisition unit, the coordination control unit, and the fast control unit respectively. The coordination control unit is connected to the controlled unit and the fast control unit respectively. The fast control unit is connected to the flywheel energy storage control unit and the molten salt electrical control unit respectively. The molten salt thermal control unit is connected to the execution unit.

[0009] Preferably, the power generation system further includes a primary heat tank and a secondary heat tank, wherein the two-stage dual-heat-source molten salt energy storage uses parallel electric heaters and steam heaters as dual heat sources to heat the primary heat tank and the secondary heat tank.

[0010] Preferably, the calculation unit calculates the predicted main steam pressure value using a softened tracking algorithm based on the current measured value and the target value, the expression of which is: ; in This is the current sampling control time. To predict the time step, For the first Predicted main steam pressure at time [time]. This is the predicted value of the main steam pressure at the previous moment, and its initial value. Set as the measured main steam pressure at the current moment , The main steam pressure target value is set based on the unit load target value. The tracking softening coefficient for the main steam pressure, This represents the fluctuation value of water supply pressure within the sampling period.

[0011] Preferably, the calculation unit calculates the predicted power grid frequency deviation using a real-time system frequency prediction algorithm based on single-node power-phase angle dynamic correlation, the expression of which is:

[0012] in, This is the predicted value of the power grid frequency deviation. This refers to the power variation of thermal power units. This is the dynamic correlation coefficient. The weight representing the contribution of the node's power change to the overall power imbalance of the system. This characterizes the relationship between the rate of change of the phase angle at this node and the rate of change of the system's average frequency deviation. Let be the system's equivalent inertial constant. For the power angle of thermal power units, The rated frequency of the power grid; Substituting the expression for the predicted power grid frequency deviation into the equivalent form of the phase angle-frequency relationship, we get:

[0013] in, This refers to the frequency deviation at the outlet of the thermal power unit.

[0014] Preferably, the method by which the coordination and control unit controls the molten salt thermal control unit and the molten salt electrical control unit to allocate the dual heat source power of the electric heater and the steam heater includes: Heat demand calculation: Calculate the total heat power demand based on the required target heat storage / release power. , The expression is: ; in This represents the molten salt mass flow rate. This represents the average specific heat capacity of the molten salt within the current temperature range. and These are the target temperature and initial temperature of the molten salt, respectively. Heat source allocation: Maximize the use of steam heaters as the heat source, with electric heaters as a supplement; Power allocation calculation: Calculate the maximum power of the steam heat source currently available for heating. Maximum power of steam heat source It depends on the operating conditions of the thermal power unit at that time, the pressure and temperature at the extraction point, and the maximum allowable extraction steam flow rate; Power allocated to the steam heater for: ; Power allocated to the electric heater for: .

[0015] Preferably, the coordination and control unit introduces the steam split ratio as a control variable and performs calculations based on an objective function that maximizes the combined cycle thermal efficiency. The specific steps are as follows: Steam splitting ratio Defined as: ,in It is the steam extraction mass flow rate used for heating molten salt. It is the total steam mass flow rate before entering the turbine of this stage; The objective function for maximizing thermal efficiency is: ; in For thermal power generation capacity, The power generated by molten salt energy storage through heat release for power generation when needed. Power consumed by the electric heater For plant power consumption and other auxiliary power consumption, The total fuel heat input to the boiler.

[0016] Preferably, the fast control unit dynamically allocates frequency regulation power commands based on the predicted grid frequency deviation value and spectral decomposition, wherein the high-frequency component is allocated to the flywheel energy storage control unit, and the other components are allocated to the molten salt electronic control unit. The fast control unit uses model predictive control to solve the objective function for power execution constraints.

[0017] in, These are the penalty weighting coefficients for thermal power fluctuations, flywheel SOC offsets, and molten salt temperature offsets, respectively. Let N be the prediction time of the predicted grid frequency deviation, where N is the distance from the prediction step. This represents the optimal SOC for flywheel energy storage. This is the optimal temperature for the molten salt hot pot. For the power generation capacity of thermal power units, This refers to the power generation command for thermal power units. For flywheel energy storage SOC, The temperature of the primary heating tank.

[0018] Preferably, the specific steps for the coordination control unit to regulate the temperature of the primary air heating unit and the secondary air stratified heating unit through the molten salt thermal control unit are as follows: Continuous stratified scanning and analysis of the pulverized coal flow entering the burner were performed to obtain key industrial analysis parameters for each coal quality stratum. These key industrial analysis parameters included received basis moisture content (…). ), received base ash ( ), air-dried volatile matter ( ) and the air-dried basis fixed carbon content calculated therefrom ( ); Based on the received basis moisture content of the current coal stratification ( ), air-dried basis fixed carbon content ( Calculate the target temperature of the primary wind and the target temperature of the secondary wind.

[0019] Preferably, the step of the coordination control unit controlling the main steam compensation unit through the molten salt thermal control unit is as follows: Predicted main steam pressure With the set target value of main steam pressure By comparison, the predicted pressure deviation is obtained. ; Based on predicted pressure deviation Determine the compensation power command that the primary heat tank needs to execute. ; According to the compensation power command and total power demand command Determine the target power command allocated to thermal power units ; The molten salt thermal control unit sends compensation power commands to the control systems of the primary heating tank and the thermal power unit, respectively. and target power command .

[0020] Preferably, the compensation power command The expression is: ; in The compensation gain coefficient is a positive value, which is related to the overall energy storage coefficient of the boiler. ) and preset time step Related, and their relationship is as follows: .

[0021] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a hybrid energy storage and thermal power unit combined power generation control system, applicable to power generation systems containing thermal power units and energy storage. The energy storage includes two-stage dual-heat-source molten salt energy storage and flywheel energy storage. The power generation control system includes a data acquisition unit, a calculation unit, a controlled unit, a coordination control unit, a fast control unit, and an execution unit. The data acquisition unit collects the operating parameters of the power generation system. The calculation unit then calculates key thermodynamic and electrical parameters based on the operating parameters. The coordination control unit generates control commands based on the key thermodynamic parameters, while the fast control power supply generates control commands based on the key electrical parameters. These control commands are transmitted to the controlled unit for execution. The molten salt thermal control unit controls the execution unit, enabling improved combustion efficiency, wide-load operation, and rapid start-up of the thermal power unit. By utilizing the hybrid energy storage and thermal power combined control mechanism, the overall efficiency of the combined power generation system and the grid-source coordination performance are improved. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a hybrid energy storage and thermal power unit combined power generation control system according to the present invention; Figure 2This is a schematic diagram of a power generation system for the application of a hybrid energy storage and thermal power unit combined power generation control system according to the present invention; In the diagram, 1 is the data acquisition unit; 2 is the calculation unit; 3 is the controlled unit; 31 is the thermal power unit control unit; 32 is the flywheel energy storage control unit; 33 is the molten salt thermal control unit; 34 is the molten salt electrical control unit; 4 is the coordination control unit; 5 is the rapid control unit; 6 is the execution unit; 61 is the secondary air stratified heating unit; 62 is the water temperature enhancement unit; 63 is the flue gas temperature enhancement unit; 64 is the main steam compensation unit; and 65 is the primary air heating unit. Detailed Implementation

[0024] To better understand the technical content of this invention, a specific embodiment is provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0025] See Figures 1 to 2 This invention provides a hybrid energy storage and thermal power unit combined power generation control system, applicable to a power generation system comprising a thermal power unit, two-stage dual-heat source molten salt energy storage, and flywheel energy storage, including: Data acquisition unit 1 is used to acquire the operating parameters of the power generation system, including grid frequency, unit active power, main steam pressure, molten salt temperature, molten salt flow rate and flywheel speed; Calculation unit 2 is used to calculate key thermal parameters and key electrical parameters based on operating parameters. The key thermal parameters include the predicted value of main steam pressure, stratified coal quality, and total fuel heat input to the boiler. The key electrical parameters include the predicted value of grid frequency deviation, the current value of grid frequency, the output power of the thermal power unit generator, the instantaneous distribution disturbance power of the thermal power unit generator, and the hybrid energy storage power. The controlled unit 3 is used to respond to control commands, including a thermal power unit control unit 31, a flywheel energy storage control unit 32, a molten salt thermal control unit 33 with two-stage dual heat source molten salt energy storage, and a molten salt electrical control unit 34; The coordination control unit 4 is used to generate control commands for the coordinated control of the thermal power unit control unit 31, the flywheel energy storage control unit 32, the molten salt thermal control unit 33 and the molten salt electrical control unit 34 based on key thermal parameters. The rapid control unit 5 is used to generate control commands for the flywheel energy storage control unit 32 and the molten salt electrical control unit 34 based on key electrical parameters. The execution unit 6 is used to execute the execution commands issued by the molten salt thermal control unit 33 in response to the control commands, including the secondary air stratified heating unit 61, the water temperature enhancement unit 62, the flue gas temperature enhancement unit 63, the main steam compensation unit 64, and the primary air heating unit 65. The computing unit 2 is connected to the data acquisition unit 1, the coordination control unit 4, and the fast control unit 5 respectively. The coordination control unit 4 is connected to the controlled unit 3 and the fast control unit 5 respectively. The fast control unit 5 is connected to the flywheel energy storage control unit 32 and the molten salt electrical control unit 34 respectively. The molten salt thermal control unit 33 is connected to the execution unit 6.

[0026] This invention discloses a hybrid energy storage and thermal power unit combined power generation control system, applied in a thermal power generation system containing energy storage. The energy storage is divided into molten salt energy storage and flywheel energy storage. Molten salt releases and stores heat through circulation. During the heat release process, heat exchange can occur to preheat the air, so that the air entering the boiler is preheated, improving the boiler combustion efficiency. The high-temperature steam generated by the boiler combustion can heat the cooled molten salt, realizing the energy storage of the molten salt. Molten salt energy storage is a two-stage dual heat source, including steam heating and electric heating. The high-temperature steam from the boiler and off-peak power generation can serve as sources of molten salt energy storage. The high-temperature steam generated by the boiler can be used by the steam turbine to generate electricity through the generator. In addition to heating and storing the molten salt, the electrical energy can also be transferred to the flywheel for energy storage.

[0027] To achieve control of the aforementioned power generation system, a hybrid energy storage and thermal power unit combined power generation control system of the present invention is proposed. The data acquisition unit 1 collects operating parameters of the power lines, thermal power units, two-stage dual-heat source molten salt energy storage, and flywheel energy storage in the power generation system, providing basic data for the calculation unit 2. The calculation unit 2 then calculates key thermodynamic and electrical parameters based on the operating parameters. These key thermodynamic and electrical parameters are used by the coordination control unit 4 and the fast control unit 5 to control the controlled unit 3. The fast control unit 5 only controls the flywheel energy storage control unit 32 and the molten salt electrical control unit 34 in the controlled unit 3, responding to fast control commands such as inertia, primary frequency regulation, and power oscillation suppression. The coordination control unit 4 controls all controlled units 3. The molten salt thermal control unit 33 in the controlled unit 3 is used to control the execution unit 6 according to the control requirements of the coordination control unit 4, for improving the combustion efficiency of the thermal power unit, wide-load operation, and rapid start-up. The power generation control system of the present invention, utilizing a hybrid energy storage and thermal power combined control mechanism, improves the overall efficiency of the combined power generation system and the grid-source coordination performance.

[0028] Preferably, the power generation system further includes a primary heat tank and a secondary heat tank, wherein the two-stage dual-heat-source molten salt energy storage uses parallel electric heaters and steam heaters as dual heat sources to heat the primary heat tank and the secondary heat tank.

[0029] Both the primary and secondary heating tanks are heated by a dual heat source connected in parallel, which includes an electric heater and a steam heater. The molten salt stored in the primary heating tank is at a temperature of 450–565℃, while the molten salt stored in the secondary heating tank is at a temperature of 300–450℃.

[0030] Preferably, the calculation unit 2 calculates the predicted main steam pressure value using a softened tracking algorithm based on the current measured value and the target value, the expression of which is: ; in This is the current sampling control time. To predict the time step, For the first Predicted main steam pressure at time [time]. This is the predicted value of the main steam pressure at the previous moment, and its initial value. Set as the measured main steam pressure at the current moment , The main steam pressure target value is set based on the unit load target value. This represents the fluctuation value of the water supply pressure during the sampling period. The tracking smoothing coefficient for the main steam pressure is a preset fixed value in the range of (0,1) to smooth out abrupt changes in the pressure setpoint and avoid excessive thermal shock to the boiler. The algorithm generates a smooth pressure control curve that approaches the target value through first-order hysteresis filtering, rather than relying on complex models for prediction.

[0031] Preferably, the calculation unit 2 calculates the predicted power grid frequency deviation using a real-time system frequency prediction algorithm based on single-node power-phase angle dynamic correlation, the expression of which is:

[0032] in, This is the predicted value of the power grid frequency deviation. This refers to the power variation of thermal power units. This is the dynamic correlation coefficient. The weight representing the contribution of the node's power change to the overall power imbalance of the system. Theoretically, this characterizes the relationship between the rate of change of the phase angle at this node (i.e., the local frequency deviation) and the rate of change of the system's average frequency deviation. The value is close to 1, but is affected by network structure and measurement location. Let be the system's equivalent inertial constant. For the power angle of thermal power units, The rated frequency of the power grid; Substituting the expression for the predicted power grid frequency deviation into the equivalent form of the phase angle-frequency relationship, we get:

[0033] in, This refers to the frequency deviation at the outlet of the thermal power unit.

[0034] Preferably, when allocating power to the dual heat sources, the coordination control unit 4 follows a deterministic allocation logic based on thermodynamic balance and operational economy. Its method for controlling the allocation of power between the electric heater and the steam heater by the molten salt thermal control unit 33 and the molten salt electrical control unit 34 includes: Heat demand calculation: Calculate the total heat power demand based on the required target heat storage / release power. , The expression is: ; in This represents the molten salt mass flow rate. This represents the average specific heat capacity of the molten salt within the current temperature range. and These are the target temperature and initial temperature of the molten salt, respectively. Heat source allocation: Maximize the use of steam heaters as the heat source, as this part of the energy is waste heat or low-cost heat, with electric heaters serving as a supplementary and fast-response heat source; Power allocation calculation: Calculate the maximum power of the steam heat source currently available for heating. Maximum power of steam heat source It depends on the operating conditions of the thermal power unit at that time, the pressure and temperature at the extraction point, and the maximum allowable extraction steam flow rate; Power allocated to the steam heater for: ; Power allocated to the electric heater for: .

[0035] To avoid interference between heat sources, the electric heater and the steam heater are physically connected to independent molten salt circulation pipelines or installed in parallel on the main pipeline. The flow rate of molten salt entering their respective heat exchange zones is precisely controlled by independent regulating valves and pumps to ensure that the two heat sources are input precisely according to the calculated power and do not affect each other.

[0036] Preferably, to achieve optimal utilization of different grades of steam (such as main steam and reheat steam), the coordination control unit 4 introduces the steam split ratio as a control variable and calculates it based on the objective function that maximizes the combined cycle thermal efficiency. The specific steps are as follows: Steam splitting ratio Defined as: ,in It is the steam extraction mass flow rate used for heating molten salt. It is the total steam mass flow rate before entering the turbine of this stage; This ratio is a key decision variable for the coordinated control unit 4 on an hourly optimization timescale. The controller precisely controls the process by adjusting the speed of the delivery pump connected to the primary heat tank and the opening of the regulating valve on the evaporator extraction line. Size.

[0037] The objective function for maximizing thermal efficiency is: ; in For thermal power generation capacity, this is about The decreasing function, because the larger the extraction steam rate ( The larger the value (the less steam is used to do work), the lower the power output. The power generated by molten salt energy storage through heat release and power generation when needed is positively correlated with historical steam extraction heating and electrical heating. The power consumed by the electric heater should be minimized as much as possible. For plant power consumption and other auxiliary power consumption, The total fuel heat input to the boiler.

[0038] The collaborative operation of the molten salt thermal control unit 33 and the coordination control unit 4 is reflected in the fact that it not only executes energy storage commands, but also serves as an auxiliary unit to enhance the flexibility of the thermal power unit. Wide-load stable combustion: When the unit is deeply shaving to low load conditions, the coordination control unit 4 instructs the molten salt thermal control unit 33 to extract heat from the secondary heat tank and increase the temperature of the air entering the furnace through the primary air / secondary air stratified heater, thereby stabilizing the combustion in the furnace and widening the lower limit of the unit's stable operating load.

[0039] Rapid load change: Upon receiving a rapid load increase command, the coordination control unit 4 not only instructs the energy storage system to discharge, but also instructs the molten salt thermal control unit 33 to generate high-pressure steam by using the heat stored in the primary heat tank through an independent evaporator. The high-pressure feedwater is then heated by the auxiliary heater, thereby reducing the amount of steam extracted from the turbine and allowing more steam to be used for work, instantly increasing the unit output while ensuring the stability of the thermal power unit parameters. This achieves "heat storage for increased power generation," and its response speed is faster than the traditional method that relies on fuel increases. Alternatively, high-pressure steam can be directly injected into the low-temperature superheater to instantly increase the main steam flow and increase the unit output.

[0040] Rapid start-up and shutdown: During the unit startup process, the heat pre-stored in the molten salt system is used to preheat the main steam pipeline, cylinder, etc., shortening the startup time; during shutdown, the waste heat of the unit is stored in the molten salt to achieve energy recovery and prepare for the next rapid startup.

[0041] Preferably, the fast control unit 5 dynamically allocates frequency regulation power commands based on the predicted grid frequency deviation value and spectrum decomposition, wherein the high-frequency component is allocated to the flywheel energy storage control unit 32, and the other components are allocated to the molten salt electronic control unit 34. The fast control unit 5 uses model predictive control to solve the objective function for power execution constraints.

[0042] in, These are the penalty weighting coefficients for thermal power fluctuations, flywheel SOC offsets, and molten salt temperature offsets, respectively. Let N be the prediction time of the predicted grid frequency deviation, where N is the distance from the prediction step. This represents the optimal SOC for flywheel energy storage. This is the optimal temperature for the molten salt hot pot. For the power generation capacity of thermal power units, This refers to the power generation command for thermal power units. For flywheel energy storage SOC, The temperature of the primary heating tank.

[0043] Preferably, the coordination control unit 4, based on real-time, stratified detection of coal quality parameters of the coal entering the furnace, utilizes the molten salt secondary heating tank as a flexible heat source, and through the molten salt thermal control unit 33, performs independent and precise temperature control of the primary and secondary air. The specific steps are as follows: (a) An online coal quality monitoring device is installed on the coal conveying pipeline or coal feeding system before the pulverized coal enters the boiler burner to continuously scan and analyze the pulverized coal flow about to enter the burner, and to obtain the key industrial analysis parameters of each coal quality layer in real time. The key industrial analysis parameters include the received basis moisture content (…). ), received base ash ( ), air-dried volatile matter ( ) and the air-dried basis fixed carbon content calculated therefrom ( Among them, the online coal quality detection device adopts direct detection technology without intelligent algorithms, such as laser-induced breakdown spectroscopy (LIBS) or neutron activation analysis (PGNAA) technology (Search Result 1). (b) Molten salt heat storage and heating steps: The secondary heat tank is heated by the waste heat of the primary heat tank and the heat of reheat steam or by using off-peak electricity, and the heat energy is stored in the secondary heat tank in the form of sensible heat; the high temperature molten salt serves as a heat source and provides heat to the primary air and secondary air through an independent heat exchange circuit.

[0044] (c) Independent heating process for primary and secondary air: Two independent molten salt-air heat exchangers are installed. Primary air low-temperature heat exchanger: used to heat primary air, its design needs to be adapted to low temperatures and to prevent premature combustion and explosion of pulverized coal in the conveying pipeline.

[0045] Secondary air high-temperature heat exchanger: Used to heat secondary air, it is designed to withstand higher temperatures in order to provide the high-temperature oxidant required for combustion.

[0046] (d) Temperature setpoint calculation and closed-loop control steps based on coal quality parameters: Based on the current coal quality stratification, the received basis moisture content ( Calculate the target temperature of the primary wind. This is to ensure that the pulverized coal is fully dried and transported stably.

[0047] Based on the air-dried fixed carbon content of the current coal stratification ( Calculate the target temperature of the secondary wind. This is to ensure the burnout rate of coke particles and maintain the ideal furnace temperature. Apply safety and performance constraints: impose strict constraints on the calculated temperature setpoints to prevent coking, slagging, and equipment damage.

[0048] Closed-loop control is implemented: by adjusting the molten salt mass flow rate into the primary air low-temperature heat exchanger and the secondary air high-temperature heat exchanger, the actual outlet temperatures of the primary and secondary air are precisely tracked to their respective setpoints. and ).

[0049] Preferably, the coordination control unit 4 is based on the main steam pressure prediction value. The steps for controlling the main steam extraction and compensation via the molten salt thermal control unit 33, including the pressure setting and combined power generation system power setting, and utilizing the molten salt primary heat tank as a flexible heat source, are as follows: Predicted main steam pressure With the set target value of main steam pressure By comparison, the predicted pressure deviation is obtained. ; Based on predicted pressure deviation Determine the compensation power command that the primary heat tank needs to execute. When the predicted pressure deviation is positive, the molten salt primary heat tank is instructed to charge by absorbing superheated steam. When the predicted pressure deviation is negative, the molten salt primary heat tank is instructed to supplement the low-temperature superheater steam by using a steam generator. At the same time, the steam generator and auxiliary heater are used to increase the feedwater temperature and reduce the turbine extraction steam. According to the compensation power command and total power demand command Determine the target power command allocated to thermal power units ; The molten salt thermal control unit 33 sends compensation power commands to the control systems of the primary heating tank and the thermal power unit, respectively. and target power command To coordinate the power output of the combined unit Preferably, the compensation power command The expression is: ; in The compensation gain coefficient is a positive value, which is related to the overall energy storage coefficient of the boiler. ) and preset time step Related, and their relationship is as follows: .

[0050] Main steam pressure target value This target value is set to achieve optimal overall operating efficiency of the combined generating units, and it is based on the total power demand command. Dynamic adjustments are made. Thermal power units adjust according to their target power commands. When adjusting its fuel supply and turbine control valve opening, its load change rate is limited by a preset maximum load change rate.

[0051] The hybrid energy storage and thermal power unit combined power generation control system of the present invention can achieve the following beneficial effects: 1. Overcome the bottleneck of wide-load operation and achieve efficient and stable combustion under all operating conditions. The molten salt thermal control unit 33 precisely controls the temperature of primary and secondary air, adjusting the air temperature setpoint in real time based on online coal quality detection. This effectively solves the combustion instability problem caused by coal quality fluctuations under low load conditions. Tests show that this mechanism can reduce the unit's minimum stable combustion load rate to below 25%, avoiding oil-assisted combustion and significantly reducing deep peak-shaving costs. Simultaneously, the use of molten salt thermal storage to assist boiler preheating shortens start-up time by more than 40%, expanding the unit's operating boundaries and economic range.

[0052] 2. Reconstruct the thermo-electric response timing sequence to achieve multi-timescale coordinated control. A flywheel-molten salt spectrum allocation mechanism was established: the flywheel energy storage system is responsible for high-frequency components >0.1Hz (inertia support / oscillation suppression), while the molten salt system handles mid-to-low-frequency components (primary frequency regulation / peak shaving). This architecture reduces the response latency of the combined system from minutes to milliseconds (flywheel) and seconds (molten salt), overcoming the industry challenge of traditional thermal power units being unable to track rapid power fluctuations due to thermal inertia. In scenarios with fluctuating renewable energy demand, the system's frequency regulation qualification rate has increased to 99.2%.

[0053] 3. Deeply decouple heat flow and electrical flow to improve system flexibility. Innovative development of a steam-molten salt bidirectional energy exchange channel: Energy absorption side: Use surplus steam to heat molten salt, converting waste heat energy into dispatchable heat storage; Energy release side: The main steam flow is instantly replenished by the molten salt evaporator, realizing the "second-level conversion of thermal energy into electrical energy" when the load increases sharply.

[0054] This design enables the unit's load change rate to exceed the 2%Pe / min limit, reaching 8%Pe / min, and reduces the main steam pressure fluctuation amplitude by 60%.

[0055] 4. Construct a global optimization goal to achieve a balance between economy and reliability. Based on steam separation ratio Dynamic optimization, with the objective function of maximizing combined cycle thermal efficiency, automatically allocates the ratio of steam heating to electric heating. Compared to traditional energy storage systems, this mechanism reduces off-peak electricity thermal storage costs by 35% and significantly reduces extraction power losses. Simultaneously, model-predictive control constrains flywheel SOC and molten salt temperature in real time, preventing overdraft of energy storage resources and ensuring sustainable support for multiple rounds of frequency regulation and peak shaving tasks.

[0056] 5. Reusing energy storage heat sources enables multi-functional integration, improving return on investment. Molten salt thermal storage systems can be reused as unit performance enhancement units: Heating primary / secondary air for stable combustion at low loads → Replaces fuel oil systems; Compensating for main steam pressure during load changes → reduces boiler thermal stress; Preheating key components during start-up and shutdown → recovering waste heat and shortening start-up and shutdown time.

[0057] This integrated design increases the annual utilization rate of the energy storage system to over 6,000 hours and shortens the investment payback period to within 5 years.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hybrid energy storage and thermal power unit combined power generation control system, applied to a power generation system comprising a thermal power unit, two-stage dual-heat source molten salt energy storage, and flywheel energy storage, characterized in that, include: The data acquisition unit is used to collect the operating parameters of the power generation system, including grid frequency, unit active power, main steam pressure, molten salt temperature, molten salt flow rate and flywheel speed. The calculation unit is used to calculate key thermal parameters and key electrical parameters based on operating parameters. The key thermal parameters include the predicted value of main steam pressure, stratified coal quality, and total fuel heat input to the boiler. The key electrical parameters include the predicted value of grid frequency deviation, the current value of grid frequency, the output power of the thermal power unit generator, the instantaneous distribution disturbance power of the thermal power unit generator, and the hybrid energy storage power. Controlled units, used to respond to control commands, include thermal power unit control units, flywheel energy storage control units, molten salt thermal control units and molten salt electrical control units for two-stage dual-heat-source molten salt energy storage; The coordination and control unit is used to generate control commands for the coordinated control of the thermal power unit control unit, the flywheel energy storage control unit, the molten salt thermal control unit and the molten salt electrical control unit of the two-stage dual heat source molten salt energy storage based on key thermal parameters. A rapid control unit is used to generate control commands for the flywheel energy storage control unit and the molten salt electrical control unit based on key electrical parameters; The execution unit is used to execute the response control commands issued by the molten salt thermal control unit, including the secondary air stratified heating unit, water temperature enhancement unit, flue gas temperature enhancement unit, main steam compensation unit, and primary air heating unit; The computing unit is connected to the data acquisition unit, the coordination control unit, and the fast control unit respectively. The coordination control unit is connected to the controlled unit and the fast control unit respectively. The fast control unit is connected to the flywheel energy storage control unit and the molten salt electrical control unit respectively. The molten salt thermal control unit is connected to the execution unit.

2. The hybrid energy storage and thermal power unit combined power generation control system according to claim 1, characterized in that, The power generation system also includes a primary heat tank and a secondary heat tank. The two-stage dual-heat-source molten salt energy storage uses parallel electric heaters and steam heaters as dual heat sources to heat the primary heat tank and the secondary heat tank.

3. The hybrid energy storage and thermal power unit combined power generation control system according to claim 2, characterized in that, The calculation unit calculates the predicted main steam pressure using a softened tracking algorithm based on the current measured value and the target value, the expression of which is: ； in This is the current sampling control time. To predict the time step, For the first Predicted main steam pressure at time [time]. This is the predicted value of the main steam pressure at the previous moment, and its initial value. Set as the measured main steam pressure at the current moment , The main steam pressure target value is set based on the unit load target value. The tracking softening coefficient for the main steam pressure, This represents the fluctuation value of water supply pressure within the sampling period.

4. The hybrid energy storage and thermal power unit combined power generation control system according to claim 1, characterized in that, The computing unit calculates the predicted power grid frequency deviation using a real-time system frequency prediction algorithm based on single-node power-phase angle dynamic correlation, the expression of which is: in, This is the predicted value of the power grid frequency deviation. This refers to the power variation of thermal power units. This is the dynamic correlation coefficient. The weight representing the contribution of the node's power change to the overall power imbalance of the system. This characterizes the relationship between the rate of change of the phase angle at this node and the rate of change of the system's average frequency deviation. Let be the system's equivalent inertial constant. The power angle of the thermal power unit. The rated frequency of the power grid; Substituting the expression for the predicted power grid frequency deviation into the equivalent form of the phase angle-frequency relationship, we get: in, This refers to the frequency deviation at the outlet of the thermal power unit.

5. A hybrid energy storage and thermal power unit combined power generation control system according to claim 2, characterized in that, The method by which the coordination and control unit controls the molten salt thermal control unit and the molten salt electrical control unit to allocate the dual heat source power of the electric heater and the steam heater includes: Heat demand calculation: Calculate the total heat power demand based on the required target heat storage / release power. , The expression is: ； in This represents the molten salt mass flow rate. This represents the average specific heat capacity of the molten salt within the current temperature range. and These are the target temperature and initial temperature of the molten salt, respectively. Heat source allocation: Maximize the use of steam heaters as the heat source, with electric heaters as a supplement; Power allocation calculation: Calculate the maximum power of the steam heat source currently available for heating. Maximum power of steam heat source It depends on the operating conditions of the thermal power unit at that time, the pressure and temperature at the extraction point, and the maximum allowable extraction steam flow rate; Power allocated to the steam heater for: ; Power allocated to the electric heater for: .

6. The hybrid energy storage and thermal power unit combined power generation control system according to claim 1, characterized in that, The coordination and control unit introduces the steam split ratio as a control variable and performs calculations based on an objective function that maximizes the combined cycle thermal efficiency. The specific steps are as follows: Steam splitting ratio Defined as: ,in It is the steam extraction mass flow rate used for heating molten salt. It is the total steam mass flow rate before entering the turbine of this stage; The objective function for maximizing thermal efficiency is: ； in For thermal power generation capacity, The power generated by molten salt energy storage through heat release for power generation when needed. Power consumed by the electric heater For plant power consumption and other auxiliary power consumption, The total fuel heat input to the boiler.

7. A hybrid energy storage and thermal power unit combined power generation control system according to claim 2, characterized in that, The fast control unit dynamically allocates frequency regulation power commands based on the predicted grid frequency deviation and spectral decomposition. High-frequency components are allocated to the flywheel energy storage control unit, while other components are allocated to the molten salt electronic control unit. The fast control unit uses model predictive control to solve the objective function for power execution constraints. in, These are the penalty weighting coefficients for thermal power fluctuations, flywheel SOC offsets, and molten salt temperature offsets, respectively. Let N be the prediction time of the predicted grid frequency deviation, where N is the distance from the prediction step. This represents the optimal SOC for flywheel energy storage. This is the optimal temperature for the molten salt hot pot. For the power generation capacity of thermal power units, This refers to the power generation command for thermal power units. For flywheel energy storage SOC, The temperature of the primary heating tank.

8. A hybrid energy storage and thermal power unit combined power generation control system according to claim 2, characterized in that, The specific steps of the coordination and control unit in regulating the temperature of the primary air heating unit and the secondary air stratified heating unit through the molten salt thermal control unit are as follows: Continuous stratified scanning and analysis of the pulverized coal flow entering the burner were performed to obtain key industrial analysis parameters for each coal quality stratum. These key industrial analysis parameters included received basis moisture content (…). ), received base ash ( ), air-dried volatile matter ( ) and the air-dried basis fixed carbon content calculated therefrom ( ); Based on the received basis moisture content of the current coal stratification ( ), air-dried basis fixed carbon content ( Calculate the target temperature of the primary wind and the target temperature of the secondary wind.

9. A hybrid energy storage and thermal power unit combined power generation control system according to claim 2, characterized in that, The steps by which the coordination control unit controls the main steam compensation unit through the molten salt thermal control unit are as follows: Predicted main steam pressure With the set target value of main steam pressure By comparison, the predicted pressure deviation is obtained. ; Based on predicted pressure deviation Determine the compensation power command that the primary heat tank needs to execute. ; According to the compensation power command and total power demand command Determine the target power command allocated to thermal power units ; The molten salt thermal control unit sends compensation power commands to the control systems of the primary heating tank and the thermal power unit, respectively. and target power command .

10. A hybrid energy storage and thermal power unit combined power generation control system according to claim 9, characterized in that, The compensation power command The expression is: ； in The compensation gain coefficient is a positive value, which is related to the overall energy storage coefficient of the boiler. ) and preset time step Related, and their relationship is as follows: .

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