A coordinated control method for a renewable energy hybrid heat-power station system

Abstract

The present invention discloses a coordinated control method for a renewable energy hybrid heat-power station. According to the DC bus voltage detected in real time by the system, the inductance current of the battery and electric boiler converter, the liquid level height and temperature at each location of the thermal cycle in the station, the water supply temperature and the outdoor temperature on the user side, the battery converter and the electric boiler converter are controlled based on the basic principle of DC motor and the basic characteristics of system operation, and a double-layer coordinated control method based on the thermal energy flow control of the mass flow of the heat storage medium in the thermal cycle in the station is used to adjust the working medium flow of the thermal energy flow to ensure that the heat load demand is met, thereby improving the controllability and flexibility of the thermal system. The method can effectively ensure the stable and reliable operation of the system, meet the multi-energy needs of users, and improve the stability of the system and the absorption capacity of renewable energy.

Description

Technical Field

[0001] The present invention belongs to the field of electrical engineering, and more specifically, relates to a coordinated control method for a renewable energy hybrid heat-power station system. Background Art

[0002] At present, it is urgent to carry out research on coordinated control methods for cogeneration systems containing a high proportion of renewable energy, so as to improve the renewable energy absorption capacity and the system's stable operation capability.

[0003] The cogeneration system makes full use of the complementary characteristics of electric energy and thermal energy to achieve the coordinated supply and comprehensive utilization of electric and thermal energy. The energy source of the hybrid thermal power station is renewable energy power generation. The power station uses power electronic converters, thermoelectric energy storage and thermoelectric conversion devices to achieve electric energy conversion, energy storage and electric-heat conversion. The operation mode and output characteristics of each link are quite different, especially there is a mismatch in time scale between the fast-response power system and the slow and large-inertia thermal system, which makes the control of the hybrid thermal power station have the characteristics of multiple time scales. Most of the existing research work focuses on the optimization of the operation mode based on the steady-state model, and few control methods consider dynamic processes. The existing control methods cannot comprehensively consider the operation and control characteristics of equipment such as energy storage devices and thermoelectric conversion devices in the thermal power station, cannot give full play to the advantages of the combination of electric and thermal systems, and lack control methods to support the stable and reliable operation of the hybrid thermal power station. Summary of the invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides a coordinated control method for a renewable energy hybrid heat-power station system, which aims to achieve stable and reliable operation of the hybrid heat-power station system, meet the user's multi-energy needs, improve the system's stability and renewable energy absorption capacity, and provide a new solution to meet the user's multi-energy needs.

[0005] To achieve the above object, according to one aspect of the present invention, a coordinated control method of a renewable energy hybrid heat-power station system is provided, wherein the system comprises: a wind turbine, an electric energy storage device, a first DC converter, an electric boiler, a second DC converter, a heat storage device, and a heat exchanger; the method comprises:

[0006] S1, respectively equating the first DC converter and the second DC converter to virtual DC motors, and controlling the virtual DC motors according to mechanical equations and armature equations thereof so as to have dynamic characteristics of DC motors;

[0007] S2, real-time detection of system water supply temperature T w , the mass flow rate m3 of the heat storage medium flowing into the heat exchanger is adjusted by PI control so that T w With its reference value Twref The deviation reaches the set threshold to achieve water supply temperature control;

[0008] Real-time detection of the working fluid level H in the hot tank h and working fluid temperature T h , H h With its reference value H href Make a difference and change T h With its reference value T href After making the difference, multiply it by the additional correction coefficient β, superimpose the above calculation results as input for PI control, and superimpose the output value with m3 to obtain the common mode component k1 of m3;

[0009] Real-time detection of electric boiler liquid level H b , H b With the set liquid level height reference value H bref After the difference is made, it is used as the input for PI control and the differential mode component k2 of m3 is output;

[0010] Superimpose k1 and k2 to obtain the mass flow rate m2 of the heat storage medium flowing into the electric boiler, and subtract k1 from k2 to obtain the mass flow rate m1 of the heat storage medium flowing out of the electric boiler, thereby realizing the control of the hot tank liquid level height, additional control of the hot tank temperature and the electric boiler liquid level height control.

[0011] Preferably, the system water supply temperature reference value T wref The calculation formula is:

[0012]

[0013]

[0014] in, is the relative heating load, T n is the design indoor temperature, T o is the actual outdoor temperature, T o ′ is the calculated outdoor temperature, T w ′ is the design water supply temperature at the user side, T h ′ is the design return water temperature on the user side, and b is the heat transfer index of the radiator.

[0015] Preferably, the mechanical equation of the virtual DC motor is:

[0016]

[0017] Where J is the virtual moment of inertia; D is the damping coefficient; ω and ω0 are the actual angular velocity and rated angular velocity respectively; T m and T e are mechanical torque and electromagnetic torque respectively; P e is the electromagnetic power of the DC motor.

[0018] Preferably, the armature equation of the virtual DC motor is:

[0019]

[0020] Where U dc is the DC bus voltage; R a is the total equivalent resistance of the armature circuit; C T and Φ are the torque coefficient and magnetic flux per pole respectively.

[0021] Preferably, the first converter and the second converter both include a bridge arm structure consisting of a switch tube, a capacitor and a filter inductor.

[0022] Preferably, S1 includes:

[0023] S11, the real-time detected DC bus voltage u dc and the system DC bus voltage reference value u dcref After making the difference, PI control is performed to output the reference value I of the converter output current. oref , will I oref and DC bus voltage reference value u dcref Multiply to get the converter active power reference value P m ;

[0024] S12, P m Divided by the rated angular velocity ω0, the mechanical torque T of the virtual DC motor is obtained m By constructing the mechanical equation and armature equation of the virtual DC motor, the armature current reference value I is obtained. a ;

[0025] S13, I a Multiply by the converter ratio k to get the converter inductor current reference value I ref , the real-time detected converter inductor current i es with I ref The difference is used as the input of the PI controller, and the on-off control signal of the switch tube in the converter is obtained through PI control and pulse width modulation.

[0026] According to another aspect of the present invention, there is provided a coordinated control system for a renewable energy hybrid thermal-power plant system, comprising: a computer-readable storage medium and a processor;

[0027] The computer-readable storage medium is used to store executable instructions;

[0028] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method as described in the first aspect.

[0029] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0030] (1) The coordinated control method of the renewable energy hybrid heat-power station system provided by the present invention is aimed at the hybrid heat-power station with renewable energy as energy input. It fully considers the operation and control characteristics of equipment such as energy storage devices and thermoelectric conversion devices in the heat-power station, and combines the characteristics of the heating pipeline network and heat load to construct a two-layer coordinated control method based on virtual DC motor control and thermal energy flow control. It can achieve the effect of coordinated operation of electric energy and thermal energy, and collaboratively completes the smooth regulation of renewable energy fluctuations in the hybrid heat-power station, effectively realizing thermoelectric complementarity and stable output of heat and electricity.

[0031] (2) The coordinated control method of the renewable energy hybrid heat-power station system provided by the present invention adopts PI control to realize the heat flow control, which has good response characteristics, low control complexity and is easy to implement in engineering. The heat flow control can make the water supply temperature, the liquid level and temperature in the hot tank, and the liquid level of the electric boiler closely follow the set value, flexibly store and release heat energy, and ensure that the heat load demand is met by adjusting the working fluid flow of the heat flow, thereby improving the controllability and flexibility of the thermal system. At the same time, the dynamic characteristics of the heat load are fully considered, so that when the external environment temperature changes, it can closely follow the load changes and adjust the water supply temperature in real time to ensure a stable heating level.

[0032] (3) The coordinated control method of the renewable energy hybrid heat-power station system provided by the present invention adopts the PI control form for the DC voltage control link and current control link of the battery converter and the electric boiler converter, which can make the output DC voltage of each inverter follow the set DC bus reference value, and make the output current of each inverter follow the set output current reference value. The actual physical quantity of the circuit can track the controller reference value well, so that the converter has good response characteristics. On the other hand, the virtual DC motor link can simulate the mechanical equation and armature equation of the actual DC motor, so that the external characteristics of the converter output terminal show the droop characteristics and dynamic characteristics consistent with the DC motor. Furthermore, the present invention realizes control completely according to the sampling values ​​of the DC bus voltage and the local output current, and can automatically realize power distribution between the two converters connected by the circuit, without the need for additional communication, so as to have good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 One of the structural diagrams of a hybrid heat-power station system based on renewable energy provided by an embodiment of the present invention;

[0034] Figure 2 The second structural diagram of the hybrid heat-power station system based on renewable energy provided by the embodiment of the present invention

[0035] Figure 3 A block diagram of the virtual DC motor control provided by the present invention;

[0036] Figure 4 A structural diagram of a converter provided by the present invention;

[0037] Figure 5 A block diagram of the thermal energy flow control provided by the present invention;

[0038] Figure 6 The power waveform diagram of the hybrid heat-power station under the condition of wind speed fluctuation provided by the present invention;

[0039] Figure 7 A DC bus voltage waveform diagram provided by the present invention;

[0040] Figure 8 (a), (b), (c), and (d) are waveform diagrams of various physical quantities on the heating network side provided by the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] The embodiment of the present invention provides a coordinated control method for a renewable energy hybrid heat-power station system. Figure 1-2 As shown, the system includes: a wind turbine set, an electric energy storage device, a first DC converter, an electric boiler, a second DC converter, a heat storage device, and a heat exchanger.

[0043] The solid lines, dashed lines and dotted lines with arrows in the figure represent the flow directions of electric energy, thermal energy and actual detection information respectively. In the figure, m1 is the mass flow rate of the heat storage medium flowing out of the electric boiler, m2 is the mass flow rate of the heat storage medium flowing into the electric boiler, and m3 is the mass flow rate of the heat storage medium flowing into the heat exchanger.

[0044] Specifically, the renewable energy hybrid heat-power station system includes a wind turbine, electric energy storage, an electric boiler, heat storage equipment (hot tank and cold tank), and a heat exchanger. The system uses the wind turbine to generate electricity. Batteries and electric boilers are used as energy storage devices to absorb and stabilize wind power generation, so that the system can smoothly transmit electricity to the power grid. The electric boiler converts the absorbed electrical energy into thermal energy to heat the heat storage medium. The heat storage equipment transmits the stored thermal energy to the heat exchanger. The heat exchanger is used to exchange energy between the heat storage medium in the station and the circulating hot water supply system to meet the thermal load requirements on the user side.

[0045] The coordinated control method provided in the embodiment of the present invention is based on the power and thermal state information of each part of the system, and establishes a corresponding control model in combination with the system operation characteristics to achieve coordinated and stable operation of the entire hybrid thermal-power station system. The method includes:

[0046] S1, respectively equating the first DC converter and the second DC converter to virtual DC motors, and controlling the virtual DC motors according to mechanical equations and armature equations thereof so as to have dynamic characteristics of DC motors;

[0047] Specifically, the DC bus voltage, the inductance current of the battery and the electric boiler converter in the system are detected in real time, and based on the basic principle of DC motors, virtual DC motor control of the electric energy storage converter (i.e., the first DC converter) and the electric boiler converter (i.e., the second DC converter) is established respectively. By controlling the first DC converter, the input / output electric energy of the electric energy storage device (e.g., the battery) is controlled; by controlling the second DC converter, the electric energy input to the electric boiler converter is controlled.

[0048] On the grid side, the battery and electric boiler converter use virtual DC motor control, which aims to enhance the inertia and stability of the DC bus voltage. Virtual DC motor control includes DC voltage control link, virtual DC motor control link, and current control link. The control block diagram is as follows: Figure 3 shown.

[0049] Preferably, a virtual DC motor mechanical equation is constructed according to the mechanical torque, rated angular velocity, virtual moment of inertia, damping coefficient, electromagnetic power and actual angular velocity of the virtual DC motor, as shown in the following formula:

[0050]

[0051] Where J is the virtual moment of inertia; D is the damping coefficient; ω and ω0 are the actual angular velocity and rated angular velocity respectively; T m and T e are mechanical torque and electromagnetic torque respectively; P e is the electromagnetic power of the DC motor, is the induced electromotive force E of the armature winding and the armature current I a The product of .

[0052] The mechanical equation of the virtual DC motor provided by the present invention can effectively improve the equivalent inertia and system damping of the DC bus by introducing virtual rotational inertia and damping coefficient, can well suppress bus voltage overshoot during power fluctuation, prevent bus voltage mutation, reduce the impact caused by power fluctuation, and greatly improve the stable operation capability of the hybrid thermal-power station. Furthermore, the present invention can better match the dynamic response characteristics of each device by adjusting different virtual rotational inertia and damping coefficients, and has good adaptability and scalability.

[0053] Preferably, a virtual DC motor armature equation is constructed according to the actually measured DC bus voltage, induced electromotive force, and total equivalent resistance of the armature circuit, as shown in the following formula:

[0054]

[0055] Where U dc is the DC bus voltage; R a is the total equivalent resistance of the armature circuit; C T and Φ are the torque coefficient and magnetic flux per pole respectively, both of which are fixed constants.

[0056] It is worth noting that the calculated command current I a is the value on the high voltage side. Assuming that the converter efficiency is 100%, the input energy on the low voltage side is equal to the output energy on the high voltage side, then the low voltage side command current I ref =U dcref ×I a / U esref That is, k=U in the control block diagram dcref / U esref .

[0057] Preferably, if Figure 4 As shown, the first converter and the second converter both include a bridge arm structure consisting of a switch tube, a capacitor and a filter inductor.

[0058] Preferably, S1 includes:

[0059] S11, DC voltage control link: the real-time detected DC bus voltage u dc and the system DC bus voltage reference value u dcref After making the difference, PI control is performed to output the reference value I of the converter output current. oref , will I oref and DC bus voltage reference value u dcref Multiply to get the converter active power reference value P m .

[0060] S12, virtual DC motor link: P m Divided by the rated angular velocity ω0, the mechanical torque T of the virtual DC motor is obtained m By constructing the mechanical equation and armature equation of the virtual DC motor, the armature current reference value I is obtained. a ;

[0061] S13, current control link: I a Multiply by the converter ratio k to get the converter inductor current reference value I ref , the real-time detected converter inductor current i es with Iref The difference is used as the input of the PI controller, and the on-off control signal of the switch tube in the converter is obtained through PI control and pulse width modulation.

[0062] The present invention fully considers the dynamic operating characteristics of each device in the hybrid thermal power station, and from the perspective of the thermal power station level, effectively supports the stable operation of the hybrid thermal power station through a two-layer coordinated control strategy based on virtual DC motor control and thermal energy flow control. Virtual DC motor control can effectively increase the inertia and damping of the system, suppress the impact of load mutations and wind fluctuations on the system, enhance the ability of energy storage to maintain the power balance of the hybrid thermal power station, and improve the power supply quality of the thermal power station. Thermal energy flow control adapts to the thermal characteristics, can effectively maintain the normal flow of thermal energy flow, ensure the normal supply of heat load, maintain the stability of the thermal cycle system, and improve the control margin of the system.

[0063] Real-time detection of the liquid level height and temperature at each point of the thermal cycle in the station, the water supply temperature (water supply temperature to the user side), and the outdoor temperature on the user side, and establish a thermal energy flow control by adjusting the mass flow rate of the heat storage medium in the thermal cycle in the station. The entire control of the thermal energy flow is mainly achieved by adjusting the mass flow rate of the working fluid through PI control to achieve flexible allocation of thermal energy transmission and storage. The heat load will change with the change of the outdoor temperature, so it is necessary to regulate the heat supply to maintain the required temperature indoors in the building. The heat supply regulation is mainly based on mass regulation, that is, under the condition of a certain heating area, the water supply mass flow rate remains unchanged, and the heat load is met by adjusting the water supply temperature. In order to ensure that the water supply temperature meets the requirements after heat exchange, this is achieved here by adjusting m3. By adjusting m1 and m2, it is ensured that the heat storage working fluid level of the electric boiler and the heat storage tank is maintained within an appropriate range. The thermal energy flow control includes water supply temperature control, hot tank liquid level height control, hot tank temperature additional control, and electric boiler liquid level height control. Its control block diagram is as follows Figure 5 shown.

[0064] S2, water supply temperature control: real-time detection of system water supply temperature T w , the mass flow rate m3 of the heat storage medium flowing into the heat exchanger is adjusted by PI control so that T w With its reference value T wref The deviation reaches the set threshold to achieve water supply temperature control.

[0065] Specifically, the water supply temperature control is to perform PI control after subtracting the real-time detected water supply temperature from the reference value of the system water supply temperature, and output a set value of the mass flow rate m3 of the heat storage working fluid flowing into the heat exchanger.

[0066] Hot tank liquid level control: Real-time detection of the liquid level H in the hot tank h and working fluid temperature T h , H hWith its reference value H href Make a difference and change T h With its reference value T href After making the difference, multiply it by the additional correction coefficient β, superimpose the above calculation results as input for PI control, and superimpose the output value with m3 to obtain the common mode component k1 of m3;

[0067] Specifically, the hot tank liquid level height control is to subtract the real-time detected hot tank liquid level height from the set hot tank liquid level height reference value, and superimpose the result with the result of the additional hot tank temperature control as the input of PI control for PI control, and add the water supply temperature control output value to obtain the common mode component of the heat storage working fluid mass flow rate.

[0068] Considering that renewable energy cannot meet the heat demand in the short term, the heat storage tank needs to release more heat storage medium to participate in heat exchange to meet the heat load demand. In order to slow down the temperature drop rate of the heat storage tank medium, an additional correction link for the heat storage tank medium temperature is added to the PI control loop that adjusts the liquid level of the heat storage tank. Figure 5 Where β is a correction coefficient, 0<β<1, and its value is set according to actual needs. If the temperature drop rate of the hot tank is required to be smaller, β is set to be larger. The additional control of the hot tank temperature is to make a difference between the real-time detected working fluid temperature in the hot tank and the set working fluid temperature in the hot tank, and multiply the difference by the additional correction coefficient β to obtain the result of the additional control of the hot tank temperature.

[0069] Real-time detection of electric boiler liquid level H b , H b With the set liquid level height reference value H bref After the difference is made, it is used as the input for PI control and the differential mode component k2 of m3 is output;

[0070] Specifically, the electric boiler liquid level control is to perform PI control after subtracting the real-time detected liquid level in the electric boiler from the set liquid level reference value, and output the differential mode component of the mass flow rate of the heat storage working fluid;

[0071] Superimpose k1 and k2 to obtain the mass flow rate m2 of the heat storage medium flowing into the electric boiler, and subtract k1 from k2 to obtain the mass flow rate m1 of the heat storage medium flowing out of the electric boiler, thereby realizing the control of the hot tank liquid level height, additional control of the hot tank temperature and the electric boiler liquid level height control.

[0072] Specifically, the common mode component and the differential mode component of the heat storage medium mass flow rate are superimposed to obtain the set value of the heat storage medium mass flow rate m2 flowing into the electric boiler. The common mode component and the differential mode component of the heat storage medium mass flow rate are subtracted to obtain the set value of the heat storage medium mass flow rate m1 flowing out of the electric boiler.

[0073] Preferably, under a certain outdoor temperature operating condition, if the indoor temperature is to be kept constant, the water supply temperature entering the heating user is T wref The following formula should be satisfied:

[0074]

[0075]

[0076] in, is the relative heating load, T n is the design indoor temperature, T o is the actual outdoor temperature, T o ′ is the calculated outdoor temperature, T w ′ is the design water supply temperature at the user side, T h ′ is the design return water temperature on the user side, and b is the radiator heat transfer index, which is determined according to the user's heat exchanger type.

[0077] The coordinated control method of the renewable energy hybrid heat-power station system provided by the present invention is further illustrated below with a specific example.

[0078] like Figure 1 As shown, the hybrid heat-power station system consists of renewable energy and its interface device, electric energy storage device, in-station heat circulation system (including electric boiler, working fluid storage tank, heat exchange device and working fluid pump and other components) and heat-power station system output interface to the power grid and heat network. The in-station heat circulation uses molten salt as the heat storage medium, which has the advantages of non-combustion, non-toxicity, low cost, and low corrosion rate compared with ordinary pipeline materials. Hot water is used as the heat carrier in the heat network, which has the advantages of high thermal energy utilization, strong heat storage capacity and large heating radius.

[0079] The parameters of various modules or devices are summarized in Table 1.

[0080] Table 1 Partial parameters of hybrid heat-power station

[0081]

[0082] The virtual DC motor parameters are designed as follows:

[0083] Referring to the actual DC motor parameters, the virtual DC motor adopts a single-wave winding, the total number of conductors of the armature winding Na = 186, the number of parallel branch pairs a = 1, and the number of pole pairs p = 2, then the torque constant is:

[0084]

[0085] Assuming the rated induced electromotive force of the DC motor is 1300V and the rated angular velocity ω0=2π×50rad / s, the magnetic flux per pole is 0.0699Wb.

[0086] It is understandable that the embodiment of the present invention takes a single-wave winding as an example, and in actual application, a single-stack winding or the like may also be used.

[0087] The virtual moment of inertia J and damping coefficient D in the control parameters should be selected according to the dynamic response time of the connected device. Considering that the response time of the electrothermal conversion device is longer than that of the electric energy storage, the value of the virtual moment of inertia of the electrothermal conversion device should be set larger than that of the electric energy storage.

[0088] Figure 6 The power waveform of the hybrid thermal power station under wind speed fluctuation, where P b is the battery charging and discharging power, P hin is the power of the electric boiler, P w is the power generated by the fan, P g is the power delivered to the grid, P out It is the heat release power of the hybrid heat-power station system to the heat network. From the figure, we can see that electric thermal energy storage can effectively smooth out power fluctuations on a short time scale, ensure stable power output to the grid, and ensure power balance of the entire system.

[0089] During the whole regulation process, the DC bus voltage U dc Fluctuates slightly around the steady-state value, such as Figure 7 As shown in the figure. Under the proposed coordinated control strategy, the voltage changes slowly when the wind speed fluctuates, the time for the voltage to stabilize increases, and the support capacity of the bus voltage is greatly improved. The proposed coordinated control strategy increases the inertia and damping of the system, which can effectively suppress the overshoot of the bus voltage when the load fluctuates, prevent the bus voltage from changing suddenly, and reduce the impact caused by power fluctuations. The stable operation capacity of the hybrid thermal power station is greatly improved.

[0090] The waveforms of the physical quantities on the heating network side are as follows: Figure 8 As shown in (a), (b), (c), and (d), T room Indicates the indoor temperature, T water Indicates the water supply temperature, T b , T h , T c Respectively represent the working medium temperature in the electric boiler, heat storage tank, and cold tank, H b , H h , H cRespectively represent the liquid level height of the working fluid in the electric boiler, heat storage tank, and cold tank. As can be seen from the figure, the heating network side is stable, the indoor temperature is maintained at a suitable temperature, the water supply temperature is basically consistent with the reference water temperature, and the wind speed fluctuation has little effect on the heating network side. The liquid level height and temperature of the electric boiler, cold tank and heat storage tank are basically maintained near the set value, and the control effect is good. The entire system can maintain stable operation over a long time scale, maintain power balance, and ensure the normal supply of heat load.

[0091] A coordinated control system of a renewable energy hybrid heat-power station system provided by the present invention is described below. An embodiment of the present invention provides a coordinated control of a renewable energy hybrid heat-power station system, including:

[0092] A computer readable storage medium and a processor;

[0093] The computer-readable storage medium is used to store executable instructions;

[0094] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method described in any of the above embodiments.

[0095] It will be easily understood by those skilled in the art that 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coordinated control method for a renewable energy hybrid heat-power station system, the system comprising: Wind turbine, electric energy storage device, first DC converter, electric boiler, second DC converter, heat storage device, heat exchanger, wherein the wind turbine, electric energy storage device, electric boiler are connected to the DC bus through AC / DC converter, first DC converter, second DC converter respectively, and the DC bus is connected to the power grid through DC / AC converter; the system generates electric energy through wind turbine, the electric energy storage device and electric boiler are used as energy storage devices to absorb and stabilize wind power generation, so that the system can smoothly transmit electricity to the power grid, the electric boiler converts the absorbed electric energy into thermal energy, heats the heat storage medium, the heat storage device transmits the stored thermal energy to the heat exchanger, the heat exchanger is used for energy exchange between the heat storage medium in the station and the circulating hot water supply system to meet the heat load demand on the user side; characterized in that the method comprises: S1, respectively equating the first DC converter and the second DC converter to virtual DC motors, and controlling the virtual DC motors according to mechanical equations and armature equations thereof so as to have dynamic characteristics of DC motors; S2, real-time detection of system water supply temperature T w , the mass flow rate m3 of the heat storage medium flowing into the heat exchanger is adjusted by PI control so that T w With its reference value T wref The deviation reaches the set threshold to achieve water supply temperature control; Real-time detection of the working fluid level H in the hot tank h and working fluid temperature T h , H h With its reference value H href The difference between h and its reference value T href The result of multiplying the difference by the additional correction coefficient β is superimposed as the input for PI control, and the output value is superimposed with m3 to obtain the common mode component k1 of m3; Real-time detection of the working fluid level H in the electric boiler b , H b With the set liquid level height reference value H bref After the difference is made, it is used as the input for PI control and the differential mode component k2 of m3 is output; Superimpose k1 and k2 to obtain the mass flow rate m2 of the heat storage medium flowing into the electric boiler, and subtract k1 from k2 to obtain the mass flow rate m1 of the heat storage medium flowing out of the electric boiler, thereby realizing the hot tank liquid level height control, the hot tank temperature additional control and the electric boiler liquid level height control.

2. The method according to claim 1, characterized in that System water supply temperature reference value T wref The calculation formula is: in, is the relative heating load, T n is the design indoor temperature, T o is the actual outdoor temperature, T o ′ is the calculated outdoor temperature, T w ′ is the design water supply temperature at the user side, T h ′ is the design return water temperature on the user side, and b is the heat transfer index of the radiator.

3. The method according to claim 1, characterized in that The mechanical equation of the virtual DC motor is: Where J is the virtual moment of inertia; D is the damping coefficient; ω and ω0 are the actual angular velocity and rated angular velocity respectively; T m and T e are mechanical torque and electromagnetic torque respectively; P e is the electromagnetic power of the DC motor.

4. The method according to claim 1 or 3, characterized in that The armature equation of the virtual DC motor is: Where U dc is the DC bus voltage; R a is the total equivalent resistance of the armature circuit; C T and Φ are the torque coefficient and magnetic flux per pole respectively.

5. The method according to claim 1, characterized in that The first DC converter and the second DC converter both include a bridge arm structure consisting of a switch tube, a capacitor and a filter inductor.

6. The method according to claim 5, characterized in that S1 includes: S11, the real-time detected DC bus voltage u dc and the system DC bus voltage reference value u dcref After making the difference, PI control is performed to output the reference value I of the converter output current. oref , will I oref and DC bus voltage reference value u dcref Multiply to get the converter active power reference value P m ; S12, P m Divide by the rated angular velocity ω0 to get the mechanical torque T of the virtual DC motor m By constructing the mechanical equation and armature equation of the virtual DC motor, the armature current reference value I is obtained. a ; S13, I a Multiply by the converter ratio k to get the converter inductor current reference value I ref , the real-time detected converter inductor current i es with I ref The difference is used as the input of the PI controller, and the on-off control signal of the switch tube in the converter is obtained through PI control and pulse width modulation.

7. A coordinated control system for a renewable energy hybrid heat-power station system, characterized in that: include: A computer readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the method according to any one of claims 1 to 6.

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