Control Method and Device for a Diesel Engine-Energy Storage Combined Power Generation System

Abstract

The present invention discloses a control method and device for a diesel engine - energy storage combined power generation system. In the diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual - winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual - winding generator, and the power winding of the dual - winding generator is connected to the grid side. The control method includes: using a first control loop to control the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controlling the output frequency through the power winding of the dual - winding generator; using a second control loop to control the output of the energy storage, and then indirectly controlling the output frequency of the power winding of the dual - winding generator through the control winding connected to the energy storage; the two frequency control loops are coupled to the power winding of the dual - winding generator through the magnetic field of the dual - winding generator to output the alternating current frequency. The present invention utilizes the complementarity of the diesel - generator and the energy storage to have an automatic voltage regulation function, which can improve the power supply quality of the photovoltaic power generation system.

Description

Technical Field

[0001] The present invention relates to the control of a hybrid power generation system, and particularly to a control method and device for a diesel engine - energy storage combined power generation system. Background Art

[0002] Existing power generation vehicles for non - stop operation use diesel engines and synchronous generators, which have the advantages of long continuous power supply time and low investment cost compared with energy storage vehicles for non - stop operation.

[0003] However, traditional diesel power generation vehicles adjust active power based on the speed regulation of diesel engines. As Figure 1 shown, the main controller of the power generation vehicle controls the operation of the engine through an engine control signal, and controls the voltage and current phase on the input side of the synchronous generator by controlling the excitation. The engine serves as a power source to provide power for the synchronous generator, causing the generator rotor to rotate and generate electricity. However, due to the large inertia and poor load following performance of diesel engines, as well as the low accuracy of diesel speed regulation and large power fluctuations, when the non - stop operation vehicle supports the load alone, the frequency deviation is large and the power supply quality is poor.

[0004] By using a diesel engine - energy storage combined power generation system, energy storage can be used for small - capacity short - time power supply requirements during non - stop operation, and the diesel engine can be used for long - time requirements, realizing non - stop operation. At the same time, the combination of diesel power generation and energy storage has an automatic voltage regulation function, which can improve the power supply quality of the photovoltaic power generation system. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a control method and device for a diesel engine - energy storage combined power generation system to improve the power quality of the electric energy output by the power winding of the generator.

[0006] Technical Solution: A control method for a diesel engine - energy storage combined power generation system. In the diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual - winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual - winding generator, and the power winding of the dual - winding generator is connected to the grid side. The control method includes:

[0007] Using the first control loop to control the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controlling the output frequency through the power winding of the dual - winding generator. The first control loop determines the first frequency deviation amount ef3 based on the frequency target value f2 of the diesel engine - dual - winding generator and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the speed deviation of the diesel engine based on the first frequency deviation amount ef3 to determine the rotational speed of the diesel engine;

[0008] The energy storage output is controlled by the second control loop, and then the output frequency of the power winding of the dual-winding generator is indirectly controlled through the control winding connected to the energy storage, and the second control loop determines the second frequency deviation amount ef4 based on the given support frequency target value f1 and the output frequency f5 of the power winding port of the dual-winding generator, and calculates the control frequency of the energy storage converter by using PID control based on the second frequency deviation amount ef4;

[0009] The two frequency control loops are coupled to the output AC frequency of the power winding of the dual-winding generator through the magnetic field of the dual-winding generator.

[0010] Further, the frequency target value f2 of the diesel engine-dual-winding generator is obtained according to the following method:

[0011] Collect the state of charge SOC of the energy storage battery, and determine the energy storage frequency adjustment deviation value ef6 through proportional control with dead zone according to the state of charge SOC of the energy storage battery;

[0012] Based on the system frequency given value f1 and the energy storage frequency adjustment deviation value ef6, the frequency target value f2 of the diesel engine-dual-winding generator is obtained according to f2 = f1 - ef6.

[0013] Further, according to the comparison between the state of charge SOC of the energy storage battery and the preset SOC 上限 and SOC 下限 to determine the energy storage frequency adjustment deviation value ef6, the calculation method is as follows:

[0014] When SOC is greater than SOC 上限 , ef6 = K soc (SOC - SOC 上限 );

[0015] When SOC is less than SOC 下限 , ef6 = K soc (SOC - SOC 下限 );

[0016] When SOC is not greater than SOC 上限 and SOC is not less than SOC 下限 , ef6 = 0;

[0017] Where Ksoc is the droop coefficient of ef6 considering the SOC parameter.

[0018] Further, the rotational speed deviation ew1 of the diesel engine is calculated according to the following proportional-integral control: ew1 = K1 P ·ef3 + K1 I ·∫ef3·dt, where K1 p is the first proportional regulation coefficient, K1 Iis the first integral regulation coefficient; the given value of the diesel engine speed w2 is obtained according to w2 = w1 + ew1, where w1 is the feedforward value of the diesel engine speed.

[0019] Furthermore, the feedforward value w1 of the diesel engine speed is calculated according to the following formula: w1 = Kw * f2, where Kw is the speed feedforward coefficient.

[0020] Furthermore, the given value f4 of the energy storage converter control frequency is calculated according to the following proportional-integral control: f4 = K2 P ·ef4 + K2 I ·∫ef4·dt, where K2 p is the second proportional regulation coefficient, and K2 I is the second integral regulation coefficient.

[0021] The present invention also provides a control device for a diesel engine - energy storage combined power generation system. In the diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual-winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual-winding generator, and the power winding of the dual-winding generator is connected to the grid side. The control device includes:

[0022] A first control module that uses the first control loop to control the rotational speed of the rotor of the dual-winding motor driven by the diesel engine, and then controls the output frequency through the power winding of the dual-winding generator. The first control loop determines the first frequency deviation amount ef3 based on the frequency target value f2 of the diesel engine - dual-winding generator and the output frequency f5 of the power winding port of the dual-winding generator, and uses PID control to calculate the speed deviation of the diesel engine based on the first frequency deviation amount ef3 to determine the diesel engine speed;

[0023] A second control module that uses the second control loop to control the energy storage output, and then indirectly controls the output frequency of the power winding of the dual-winding generator through the control winding connected to the energy storage. The second control loop determines the second frequency deviation amount ef4 based on the given support frequency target value f1 and the output frequency f5 of the power winding port of the dual-winding generator, and uses PID control to calculate the control frequency of the energy storage converter based on the second frequency deviation amount ef4;

[0024] The two frequency control loops are coupled to the power winding of the dual-winding generator through the magnetic field of the dual-winding generator to output the AC power frequency.

[0025] The present invention also provides a computer device, including:

[0026] One or more processors;

[0027] A memory; and

[0028] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and when the programs are executed by the processor, the steps of the control method of the diesel engine - energy storage combined power generation system as described above are implemented.

[0029] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the control method of the diesel engine - energy storage combined power generation system as described above are implemented.

[0030] Beneficial effects: Based on the fast regulation characteristics of energy storage, the present invention utilizes two frequency control loops to compensate for the fluctuations in the output power of the diesel engine and the problem of unstable frequency through the control winding - power winding of the dual-winding motor, improving the power quality of the electric energy output by the power winding. Description of the Drawings

[0031] Figure 1 Is a topological schematic diagram of a traditional diesel power generation vehicle;

[0032] Figure 2 Is a topological schematic diagram of the diesel engine - energy storage combined power generation system of the present invention;

[0033] Figure 3 Is the control logic of the diesel engine - energy storage combined power generation system of the present invention;

[0034] Figure 4 Is a flowchart of the control method of the diesel engine - energy storage combined power generation system of the present invention;

[0035] Figure 5 Is the output frequency of the diesel power generation vehicle without energy storage compensation in the embodiment of the present invention;

[0036] Figure 6 Is the output frequency of the diesel power generation vehicle with diesel engine - energy storage combined power generation in the embodiment of the present invention. Detailed Embodiments

[0037] The following further clarifies the present invention in conjunction with the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent modifications of the present invention by those skilled in the art all fall within the scope defined by the appended claims of this application.

[0038] Such as Figure 2As shown in the figure, in the diesel engine - energy storage combined power generation system of the present invention, energy storage is added to the diesel power generation system, and a dual - winding generator is used to replace the traditional synchronous generator. The dual - winding generator has a control winding and a power winding. The diesel engine is mechanically connected to the rotor of the dual - winding generator through a rotating shaft, and the energy storage (battery module) is connected to the control winding. The problem of large output frequency deviation and poor power supply power quality caused by the fluctuation of the diesel engine in the power generation system can be corrected by the additional energy storage configured in the control winding.

[0039] Figure 3 The control logic of the power generation system of the present invention is shown. The control system mainly includes 2 parallel frequency - control closed - loops. The first control loop controls the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controls the output frequency through the power winding of the dual - winding generator. The second control loop controls the output of the battery module (i.e., energy storage), and indirectly controls the output frequency of the power winding of the dual - winding generator through the connected control winding. The two frequency - control loops are coupled to the power winding of the dual - winding generator through the magnetic field to output the alternating - current frequency. Among them, the first control loop applies the feed - forward compensation method to improve the sensitivity under constant - frequency control and make up for the disadvantage of the large inertia of the diesel engine, rotating shaft and rotor of the dual - winding generator. The first control loop is mainly integral control to reduce the valve - regulating frequency of the diesel engine; the second control loop is mainly proportional control, and uses the zero - inertia and fast - regulation characteristics of the energy - storage converter to improve the frequency - control accuracy. Further, an energy - storage power - quantity control loop is added outside the first control loop. By adjusting the frequency target value of the first control loop, the power flow of the second control loop is indirectly adjusted, and then the battery - module power quantity is adjusted.

[0040] Figure 3 The definitions of each control variable in the control system are as follows: The frequency f1 is the given support - frequency target value, ef6 is the frequency - adjustment deviation value obtained by the proportional control of the energy - storage SOC with a dead zone, f2 is the given value of the output frequency of the diesel - engine - dual - winding generator considering the energy - storage SOC balance, w1 is the given value of the diesel - engine rotational speed by feed - forward, ef3 is the frequency - deviation amount between the given frequency f2 and the output frequency f5, ew1 is the rotational - speed error - adjustment value of the diesel engine, w2 is the given value of the diesel - engine rotational speed, T1 is the torque of the diesel engine, ef4 is the frequency difference of the control winding of the dual - winding generator, f4 is the given value of the frequency output by the energy - storage converter, I1 is the current of the control winding of the dual - winding generator, and f5 is the frequency output by the power winding of the dual - winding generator.

[0041] Refer to Figure 4 , for the control method of the diesel - powered vehicle based on a dual - winding generator, the following steps are included:

[0042] 1. Enter the control interrupt;

[0043] 2. The energy storage converter collects the battery module 101's state of charge (SOC), and determines the energy storage frequency adjustment deviation value ef6 through proportional control with dead zone. Specifically, ef6 is calculated as follows:

[0044] When SOC is greater than SOC 上限 , ef6 = K soc (SOC - SOC 上限 );

[0045] When SOC is less than SOC 下限 , ef6 = K soc (SOC - SOC 下限 );

[0046] When SOC is not greater than SOC 上限 and SOC is not less than SOC 下限 , ef6 = 0;

[0047] Where Ksoc is the ef6 droop coefficient considering the SOC parameter;

[0048] 3. Calculate the diesel engine - dual - winding generator frequency target value f2 from the system frequency given value f1, f2 = f1 - ef6;

[0049] 4. Calculate the feed - forward value w1 of the diesel engine speed from f2, w1 = Kw * f2;

[0050] Where Kw is the speed feed - forward coefficient, and Kw should preferably be taken as the ratio of the engine rated speed to the generator rated frequency.

[0051] 5. Collect the output frequency f5 at the power winding port of the dual - winding generator, and calculate ef3, ef3 = f2 - f5;

[0052] 6. Calculate the diesel engine speed deviation ew1, ew1 = K1 P ·ef3 + K1 I ·∫ef3·dt; Where K1 p is the first proportional regulation coefficient, and K1 I is the second integral regulation coefficient.

[0053] 7. Calculate the diesel engine speed given value w2, w2 = w1 + ew1;

[0054] 8. Calculate the dual - winding generator control winding frequency difference ef4, ef4 = f1 - f5;

[0055] 9. Calculate the energy storage converter control frequency given value f4, f4 = K2 P ·ef4 + K2 I ·∫ef4·dt; Where K2 p is the second proportional regulation coefficient, and K2I is the second integral regulation coefficient.

[0056] 10. The control ends. Wait for the next interruption and repeat step 1.

[0057] In the above control process, the engine control speed is w2, and the control frequency of the energy storage converter for the control winding is f4. When the actual speed and torque of the engine jitter, thus affecting the power winding frequency output f5, the control algorithm can quickly adjust f4 to achieve the rapid stabilization of f5, avoiding the problem that it is difficult for a diesel engine to quickly adjust its speed due to its large inertia.

[0058] In one embodiment, the dual-winding generator is selected with a capacity of 500 kW, 2 pairs of poles, and a rated speed of 1500 r / min; the SOC is set 上限 to 0.95, the SOC 下限 is 0.2, K soc = 100, Kw = 30, K1 p = 0, K1 I = 0.02, K2 p = 50, K2 I = 0.002, and the control frequency is selected as 20 kHz.

[0059] Therefore, a cycle is entered every 0.05 ms. The calculation of the cycle program and control parameters at a certain moment is as follows:

[0060] 1. Enter the interruption;

[0061] 2. Detect that the energy storage SOC is 0.195 and calculate ef6 = -0.5;

[0062] 3. The frequency command f1 = 50 Hz, then f2 = 50.5 Hz;

[0063] 4. The feedforward command value of the diesel engine speed w1 = 1515 r / min;

[0064] 5. Collect the output frequency f5 = 50.02 Hz and calculate ef3 = 0.48 Hz;

[0065] 6. Calculate ew1 = 0.0096 r / min;

[0066] 7. Calculate w2 = 1515.0096 r / min;

[0067] 8. Calculate ef4 = -0.02;

[0068] 9. Calculate f4 = 49.5 Hz.

[0069] The rapid stabilization of f5 is achieved by adjusting f4.

[0070] Figure 5 and Figure 6 are respectively the output frequency of the diesel generator vehicle without energy storage compensation and the output frequency of the diesel generator vehicle of the present invention in the example, where the horizontal axis represents time in s and the vertical axis represents frequency. Specifically, Figure 5 is the frequency response of the traditional diesel engine topology when the load increases from 20% of the rated value to 100%, and the response time is about 10 s. Figure 6 is the frequency response of the topology and control method proposed by the present invention when the load increases from 20% of the rated value to 100%, and the response time is about 5 s. Compared with the traditional diesel generator vehicle, the control method of the present invention improves the frequency response speed and the output electric energy is more stable.

[0071] The present invention also provides a control device for a diesel engine - energy storage combined power generation system. In the diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual - winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual - winding generator, and the power winding of the dual - winding generator is connected to the grid side. The control device includes:

[0072] A first control module that uses a first control loop to control the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controls the output frequency through the power winding of the dual - winding generator. The first control loop determines a first frequency deviation amount ef3 based on the frequency target value f2 of the diesel engine - dual - winding generator and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the rotational speed deviation of the diesel engine based on the first frequency deviation amount ef3 to determine the rotational speed of the diesel engine;

[0073] A second control module that uses a second control loop to control the output of the energy storage, and then indirectly controls the output frequency of the power winding of the dual - winding generator through the control winding connected to the energy storage. The second control loop determines a second frequency deviation amount ef4 based on the given support frequency target value f1 and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the control frequency of the energy storage converter based on the second frequency deviation amount ef4;

[0074] The two frequency control loops are magnetically coupled to the power winding of the dual - winding generator through the magnetic field of the dual - winding generator to output the alternating current frequency.

[0075] According to an embodiment of the present invention, the frequency target value f2 of the diesel engine - dual - winding generator is obtained by the following method:

[0076] Collect the state of charge SOC of the energy storage battery, and determine the energy storage frequency adjustment deviation value ef6 through proportional control with dead zone according to the state of charge SOC of the energy storage battery;

[0077] Based on the system frequency set value f1 and the energy storage frequency adjustment deviation value ef6, the diesel engine - dual - winding generator frequency target value f2 is obtained according to f2 = f1 - ef6.

[0078] Among them, the calculation of the energy storage frequency adjustment deviation value ef6 is determined according to the difference between the state of charge SOC of the energy storage battery and the preset SOC 上限 and SOC 下限 , and the calculation method is as follows:

[0079] When SOC is greater than SOC 上限 , ef6 = K s o c (SOC - SOC 上限 );

[0080] When SOC is less than SOC 下限 , ef6 = K s o c (SOC - SOC 下限 );

[0081] When SOC is not greater than SOC 上限 and SOC is not less than SOC 下限 , ef6 = 0;

[0082] Among them, Ksoc is the ef6 droop coefficient considering the SOC parameter.

[0083] According to the embodiment of the present invention, the rotational speed deviation ew1 of the diesel engine is calculated according to the following proportional - integral control: ew1 = K1 P ·ef3 + K1 I ·∫ef3·dt, where K1 p is the first proportional regulation coefficient, and K1 I is the first integral regulation coefficient; the diesel engine speed set value w2 is obtained according to w2 = w1 + ew1, where w1 is the feed - forward value of the diesel engine speed. The feed - forward value w1 of the diesel engine speed is calculated according to the following formula: w1 = Kw*f2, where Kw is the speed feed - forward coefficient.

[0084] According to the embodiment of the present invention, the energy storage converter control frequency set value f4 is calculated according to the following proportional - integral control: f4 = K2 P ·ef4 + K2 I ·∫ef4·dt, where K2 p is the second proportional regulation coefficient, and K2 I is the second integral regulation coefficient.

[0085] The present invention also provides a computer device, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and when the program is executed by the processor, the steps of the control method of the diesel engine - energy storage combined power generation system as described above are implemented.

[0086] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the control method of the diesel engine - energy storage combined power generation system as described above are implemented.

Claims

1. A control method for a combined power generation system of a diesel engine and energy storage, characterized in that, In a diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual - winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual - winding generator, and the power winding of the dual - winding generator is connected to the grid side. The control method includes: Using the first control loop to control the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controlling the output frequency through the power winding of the dual - winding generator. The first control loop determines the first frequency deviation amount ef3 based on the diesel engine - dual - winding generator frequency target value f2 and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the rotational speed deviation of the diesel engine based on the first frequency deviation amount ef3 to determine the rotational speed of the diesel engine; Using the second control loop to control the output of the energy storage, and then indirectly controlling the output frequency of the power winding of the dual - winding generator through the control winding connected to the energy storage. The second control loop determines the second frequency deviation amount ef4 based on the given support frequency target value f1 and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the control frequency of the energy storage converter based on the second frequency deviation amount ef4; The two frequency control loops are magnetically coupled to the power winding of the dual - winding generator through the magnetic field of the dual - winding generator to output the alternating current frequency.

2. The method according to claim 1, wherein The diesel engine - dual - winding generator frequency target value f2 is obtained according to the following method: Collect the state of charge (SOC) of the energy storage battery, and determine the energy storage frequency adjustment deviation value ef6 through proportional control with dead zone according to the SOC of the energy storage battery; Based on the system frequency set value f1 and the energy storage frequency adjustment deviation value ef6, the diesel engine - dual - winding generator frequency target value f2 is obtained according to f2 = f1 - ef6.

3. The method according to claim 2, wherein According to the state of charge (SOC) of the energy storage battery and the preset SOC 上限 and SOC 下限 Compare to determine the energy storage frequency adjustment deviation value ef6. The calculation method is as follows: When SOC is greater than SOC 上限 then, ef6 = K soc (SOC - SOC 上限 ) When SOC is less than SOC 下限 ef6 = K soc (SOC - SOC 下限 ) When the state of charge (SOC) is not greater than SOC 上限 and the SOC is not less than SOC 下限 then ef6 = 0; Where Ksoc is the droop coefficient of ef6 considering the SOC parameter.

4. The method according to claim 1, wherein The rotational speed deviation ew1 of the diesel engine is calculated according to the following proportional-integral control: ew1 = K1 P ·ef3 + K1 I ·∫ef3·dt, where K1 p is the first proportional regulation coefficient, and K1 I is the first integral regulation coefficient; the rotational speed set value w2 of the diesel engine is obtained according to w2 = w1 + ew1, where w1 is the feedforward value of the rotational speed of the diesel engine.

5. The method according to claim 4, characterized in that The feed - forward value w1 of the rotational speed of the diesel engine is calculated according to the following formula: w1 = Kw * f2, where Kw is the rotational speed feed - forward coefficient.

6. The method according to claim 1, characterized in that, Calculate the given value f4 of the energy storage converter control frequency according to the following proportional-integral control: f4 = K2 P ·ef4 + K2 I ·∫ef4·dt, where K2 p is the second proportional regulation coefficient, and K2 I is the second integral regulation coefficient.

7. A control device for a diesel engine - energy storage combined power generation system, characterized in that, In a diesel engine - energy storage combined power generation system, the diesel engine is connected to the rotor of a dual - winding generator through a rotating shaft, the energy storage is connected to the control winding of the dual - winding generator, and the power winding of the dual - winding generator is connected to the grid side. The control device includes: A first control module that uses the first control loop to control the rotational speed of the rotor of the dual - winding motor driven by the diesel engine, and then controls the output frequency through the power winding of the dual - winding generator. The first control loop determines the first frequency deviation amount ef3 based on the diesel engine - dual - winding generator frequency target value f2 and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the rotational speed deviation of the diesel engine based on the first frequency deviation amount ef3 to determine the rotational speed of the diesel engine; A second control module that uses the second control loop to control the output of the energy storage, and then indirectly controls the output frequency of the power winding of the dual - winding generator through the control winding connected to the energy storage. The second control loop determines the second frequency deviation amount ef4 based on the given support frequency target value f1 and the output frequency f5 of the power winding port of the dual - winding generator, and uses PID control to calculate the control frequency of the energy storage converter based on the second frequency deviation amount ef4; Two frequency control loops are coupled to the power winding of a dual-winding generator through the magnetic field of the dual-winding generator to output the alternating current frequency.

8. A computer device, characterized in that, Including: One or more processors; A memory; And One or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the programs are executed by the processors, the steps of the control method of the diesel engine-energy storage combined power generation system according to any one of claims 1-6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the control method of the diesel engine-energy storage combined power generation system according to any one of claims 1-6 are implemented.

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