Simulation system and method for four-stroke turbocharged diesel generator sets in nuclear power plants

Abstract

The present invention relates to a simulation system and method for a four-stroke turbocharged diesel generator set in a nuclear power plant, including: a governor-turbine model of a four-stroke turbocharged diesel generator set in a nuclear power plant; the governor-turbine model includes: a diesel engine module, an actuator module and a controller module; the controller module, the actuator module and the diesel engine module are connected in sequence; the controller module uses a preset algorithm to adjust parameters and outputs a control signal; the actuator module establishes a relationship between a throttle angle of a diesel generator and an input current, and outputs a drive signal according to a control signal output by the controller module; the diesel engine module establishes a functional relationship between an injection amount and an output power of a diesel generator, and performs driving based on the functional relationship between the injection amount and the output power of the diesel generator and the drive signal. The governor-turbine model of the present invention can be used for the parameter adjustment process in the simulation test process, and for carrying out capacity calculation and loading and unloading dynamic simulation analysis of diesel generators in nuclear power plants.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power plant generators, and more specifically to a simulation system and method for a four-stroke turbocharged diesel generator set in a nuclear power plant. Background Art

[0002] The diesel generator system serves as the backup AC power supply for the nuclear power plant. In the event of a complete loss of off-site power supply, the diesel generator system will start to provide AC power for the nuclear power plant's electrical equipment, ensuring that the electrical equipment within the plant can perform its intended safety functions and ensure the safety of the nuclear power plant's equipment and / or personnel.

[0003] The existing nuclear power plant diesel generator sets use imported models, and their supporting electronic regulators are also all imported equipment. In actual engineering projects, the height of nuclear power plant emergency diesel generator sets is subject to the supplier, and for the dynamic simulation analysis of nuclear power plant diesel generator sets, only the default electronic governor model of the software can be used, which cannot truly match the performance of nuclear power plant diesel generator sets and cannot obtain true simulation analysis results.

[0004] To solve this problem, the commonly used diesel engine model is DT (Diesel-Engine), which represents a simple diesel engine and speed control system. This solution is not suitable for the four-stroke turbocharged diesel generator set in nuclear power plants and cannot be applied to the dynamic simulation analysis of diesel generator sets in nuclear power plants.

[0005] Alternatively, the Woodward governor can be used in other methods. This type of governor-turbine represents the Woodward 2301 and 2301A speed control system, which consists of a diesel turbine system and a load sharing function. It does not match the governor model of the four-stroke turbocharged diesel generator set actually used in nuclear power plants. During the implementation of actual engineering projects, if the above model is used to carry out dynamic simulation of diesel engines, the matching of the above multiple constant values ​​with the unit performance cannot be determined, and it cannot be applied to the dynamic simulation analysis of diesel generator sets in nuclear power plants. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a simulation system and method for a four-stroke turbocharged diesel generator set in a nuclear power plant in view of the defects of the prior art.

[0007] The technical solution adopted by the present invention to solve the technical problem is: constructing a simulation system for a four-stroke turbocharged diesel generator set in a nuclear power plant, including: a governor-turbine model for a four-stroke turbocharged diesel generator set in a nuclear power plant;

[0008] The governor-turbine model includes: a diesel engine module, an actuator module and a controller module;

[0009] The controller module, the actuator module and the diesel engine module are connected in sequence;

[0010] The controller module uses a preset algorithm to adjust parameters and outputs a control signal to the actuator module;

[0011] The actuator module is used to establish the relationship between the throttle angle of the diesel generator and the input current, and output a drive signal to the diesel engine module according to the control signal output by the controller module;

[0012] The diesel engine module is used to establish a functional relationship between the fuel injection amount and the output power of the diesel generator, and perform driving based on the functional relationship between the fuel injection amount and the output power of the diesel generator and the driving signal.

[0013] In the simulation system of the four-stroke turbocharged diesel generator set of a nuclear power plant described in the present invention, the diesel engine module includes: a fuel injection quantity-power model;

[0014] The diesel engine model obtains the fuel injection quantity-power model based on the functional relationship between the fuel injection quantity and the output power of the diesel generator.

[0015] In the simulation system of the four-stroke turbocharged diesel generator set of a nuclear power plant described in the present invention, the diesel engine model obtains the fuel injection amount-power model based on the functional relationship between the fuel injection amount and the output power of the diesel generator, including:

[0016] According to the relationship between heat energy and mechanical energy, a functional relationship between fuel injection volume and diesel generator output power is established;

[0017] Determine the delay time;

[0018] According to the functional relationship between the delay time and the injection amount and the output power of the diesel generator, the diesel generator injection amount-power system transfer function is obtained; the diesel generator injection amount-power system transfer function is the injection amount-power model.

[0019] In the simulation system of the four-stroke turbocharged diesel generator set in a nuclear power plant described in the present invention, the actuator module is an inverse logic actuator.

[0020] In the simulation system of the nuclear power plant four-stroke turbocharged diesel generator set of the present invention, the actuator module includes: an angle-current model;

[0021] The angle-current model is obtained according to the relationship between the throttle angle of the diesel generator and the input current.

[0022] In the simulation system of the nuclear power plant four-stroke turbocharged diesel generator set of the present invention, the angle-current model is obtained according to the relationship between the throttle angle of the diesel generator and the input current, and the angle-current model includes:

[0023] Get the relationship between the throttle angle and input current of the diesel generator;

[0024] Determine the actuator's response time from current input to angle output change;

[0025] The angle-current model is obtained according to the response time and the relationship between the throttle angle of the diesel generator and the input current.

[0026] In the simulation system of the nuclear power plant four-stroke turbocharged diesel generator set of the present invention, the controller module includes: a PID controller;

[0027] The controller module uses a PID control algorithm based on the PID controller to adjust parameters and output the control signal.

[0028] In the simulation system of the nuclear power plant four-stroke turbocharged diesel generator set of the present invention, the controller module is also used for:

[0029] amplifying the control signal;

[0030] Subtract the amplified control signal from the upper limit of the control instruction to obtain a control signal difference;

[0031] The control signal difference is sent to the actuator module.

[0032] In the simulation system of the nuclear power plant four-stroke turbocharged diesel generator set of the present invention, the PID controller includes:

[0033] A proportional adjustment unit, wherein the proportional adjustment unit is used to proportionally adjust the deviation signal;

[0034] An integral adjustment unit, wherein the integral adjustment unit is used to eliminate static error;

[0035] A differential adjustment unit, wherein the differential adjustment unit is used to adjust the deviation signal.

[0036] The present invention also provides a simulation method for a four-stroke turbocharged diesel generator set in a nuclear power plant. The simulation method is based on a governor-turbine model of the four-stroke turbocharged diesel generator set in a nuclear power plant for simulation. The simulation method comprises the following steps:

[0037] The controller module uses a preset algorithm to adjust parameters and outputs control signals to the actuator module;

[0038] The actuator module establishes the relationship between the throttle angle of the diesel generator and the input current, and outputs a drive signal to the diesel engine module according to the control signal output by the controller module;

[0039] The diesel engine module establishes a functional relationship between the fuel injection amount and the output power of the diesel generator, and performs driving based on the functional relationship between the fuel injection amount and the output power of the diesel generator and the driving signal.

[0040] The simulation system and method for a four-stroke turbocharged diesel generator set in a nuclear power plant implementing the present invention have the following beneficial effects: including: a governor-turbine model of a four-stroke turbocharged diesel generator set in a nuclear power plant; the governor-turbine model includes: a diesel engine module, an actuator module and a controller module; the controller module, the actuator module and the diesel engine module are connected in sequence; the controller module uses a preset algorithm to adjust parameters and outputs a control signal; the actuator module establishes a relationship between the throttle angle of the diesel generator and the input current, and outputs a drive signal according to the control signal output by the controller module; the diesel engine module establishes a functional relationship between the injection amount and the output power of the diesel generator, and performs driving based on the functional relationship between the injection amount and the output power of the diesel generator and the drive signal. The governor-turbine model of the present invention can be used to simulate the parameter adjustment process in the test process, and to carry out capacity calculation and loading and unloading dynamic simulation analysis of the diesel generator in a nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0042] Figure 1 It is a structural schematic diagram of a simulation system for a four-stroke turbocharged diesel generator set in a nuclear power plant provided by an embodiment of the present invention;

[0043] Figure 2 It is a schematic diagram of a governor-turbine model for a four-stroke turbocharged diesel generator set in a nuclear power plant provided by an embodiment of the present invention;

[0044] Figure 3 is a schematic diagram of an input-output test curve of an actuator module provided in an embodiment of the present invention;

[0045] Figure 4 It is a schematic diagram of a load sudden increase response curve of the speed governor of the present invention;

[0046] Figure 5 It is a schematic diagram of the load sudden drop response curve of the speed governor of the present invention;

[0047] Figure 6 It is a flow chart of a simulation method for a four-stroke turbocharged diesel generator set in a nuclear power plant provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0049] The present invention makes the energy conversion process of the prime mover in the diesel generator and the mechanical characteristics of its fuel regulation system equivalent through a mathematical model, thereby obtaining a governor-turbine model suitable for a four-stroke turbocharged diesel generator set in a nuclear power plant. This model can be used to simulate the parameter adjustment process during the test and to carry out capacity calculation and loading and unloading dynamic analysis of the diesel generator in the nuclear power plant. The governor-turbine model that matches the unit performance of the diesel generator is used to evaluate the voltage and frequency curves and characteristics of the diesel generator output, and a corresponding diesel engine capacity and loading sequence adjustment recommendation is given.

[0050] Specifically, refer to Figure 1 , which is a structural schematic diagram of an optional embodiment of a simulation system for a four-stroke turbocharged diesel generator set in a nuclear power plant provided by the present invention.

[0051] The simulation system of the four-stroke turbocharged diesel generator set of the nuclear power plant includes: a governor-turbine model for the four-stroke turbocharged diesel generator set of the nuclear power plant.

[0052] Specifically, Figure 1 As shown, the governor-turbine model of the four-stroke turbocharged diesel generator set of the nuclear power plant includes: a diesel engine module 30 , an actuator module 20 and a controller module 10 .

[0053] The schematic diagram of the governor-turbine model of the four-stroke turbocharged diesel generator set of the nuclear power plant is as follows: Figure 2 shown.

[0054] in, Figure 2 The symbols in are explained in the following table:

[0055]

[0056]

[0057] The controller module 10, the actuator module 20 and the diesel engine module 30 are connected in sequence.

[0058] In the embodiment of the present invention, the controller module 10 uses a preset algorithm to adjust parameters and outputs a control signal to the actuator module 20 .

[0059] In the embodiment of the present invention, the actuator module 20 is used to establish the relationship between the throttle angle of the diesel generator and the input current, and output a driving signal to the diesel engine module 30 according to the control signal output by the controller module 10 .

[0060] In the embodiment of the present invention, the diesel engine module 30 is used to establish a functional relationship between the fuel injection amount and the output power of the diesel generator, and to perform driving based on the functional relationship between the fuel injection amount and the output power of the diesel generator and the driving signal.

[0061] Optionally, in the embodiment of the present invention, the diesel engine module 30 includes: a fuel injection quantity-power model. The diesel engine model obtains the fuel injection quantity-power model based on the functional relationship between the fuel injection quantity and the output power of the diesel generator.

[0062] Specifically, in an embodiment of the present invention, the diesel engine model obtains the fuel injection amount-power model based on the functional relationship between the fuel injection amount and the output power of the diesel generator, including: establishing a functional relationship between the fuel injection amount and the output power of the diesel generator according to the relationship between thermal energy and mechanical energy; determining the delay time; according to the delay time and the functional relationship between the fuel injection amount and the output power of the diesel generator, obtaining the diesel generator fuel injection amount-power system transfer function; the diesel generator fuel injection amount-power system transfer function is the fuel injection amount-power model.

[0063] Specifically, in the embodiment of the present invention, the output power of the diesel generator after the thermal energy is converted into mechanical energy can be calculated according to the injection amount as follows:

[0064] W=η i q HV q fuel (1).

[0065] Among them, q fuel (kg / s) is the fuel mass flow rate, q HV is the lower calorific value of fuel oil, η i is the indicated thermal efficiency. HV With η i Data is provided by diesel generator production data.

[0066] Furthermore, there is a certain time delay τ from the moment diesel is injected into the cylinder to the moment combustion begins. According to the empirical formula:

[0067]

[0068] From this, the diesel generator injection quantity-power system transfer function can be obtained as follows:

[0069]

[0070] Among them, W(s), u(s) are the Laplace transform of diesel engine power and injection amount.

[0071] K f : The injection amplification factor can be determined based on the relationship between the actuator and the diesel generator injection, and the value is K according to experience f=1.4205.

[0072] K e : Diesel generator power magnification factor, η i q HV / 1000=0.0176.

[0073] T e : The time constant of the fuel injection actuators such as the connecting rod, throttle, and high-pressure fuel pump in the diesel generator that affect the speed of fuel injection is selected based on experience. e =0.2.

[0074] τ: Delay time constant of diesel generator, which can be taken as τ≈0.02 near the rated speed of diesel generator.

[0075] Optionally, in an embodiment of the present invention, the actuator module 20 is an inverse logic actuator.

[0076] Optionally, in an embodiment of the present invention, the angle-current model is obtained based on the relationship between the throttle angle of the diesel generator and the input current, and the angle-current model includes: obtaining the relationship between the throttle angle of the diesel generator and the input current; determining the response time of the actuator from the current input to the angle output change; and obtaining the angle-current model based on the response time and the relationship between the throttle angle of the diesel generator and the input current. Furthermore, in an embodiment of the present invention, the throttle angle of the diesel generator is linearly related to the input current. Based on this, the relationship between the throttle angle of the diesel generator and the input current can be calculated according to the data to obtain the angle-current model.

[0077] Specifically, according to the following table and Figure 3 The relationship between the throttle angle and input current of the diesel generator is obtained from the actuator input-output test curve.

[0078]

[0079] Among them, the relationship between the diesel generator throttle angle and the input current is expressed as follows:

[0080]

[0081] Considering that the actuator needs a certain response time T from current input to angle output change a , but the response time of the actuator is short and difficult to measure. According to experience, T a =0.1, so we can get:

[0082]

[0083] Further organized into:

[0084]

[0085] Among them, a(s) and i(s) are the Laplace transform of the actuator output angle and its input current respectively.

[0086] Optionally, in an embodiment of the present invention, the controller module 10 includes: a PID controller. The controller module 10 uses a PID control algorithm based on the PID controller to adjust parameters and output a control signal.

[0087] Furthermore, in this embodiment, the controller module 10 is also used to: amplify the control signal; subtract the amplified control signal from the upper limit of the control instruction to obtain a control signal difference; and send the control signal difference to the actuator module 20.

[0088] Specifically, the transfer function expression of the PID controller is as follows:

[0089]

[0090] Where c(s) and e(s) are the Laplace transforms of the control command and the speed error, respectively. P is the proportional link gain, K I is the integral link gain, K D is the differential adjustment unit gain.

[0091] After the PID controller performs parameter adjustment and outputs a control signal, the control signal is amplified by a factor C and then subtracted from the set upper limit of the control instruction. The obtained difference acts on the actuator module 20 .

[0092] Among them, C is the control command amplification factor, which is convenient for the PID controller to adjust and can be set manually, for example, it can be 20. max The upper limit of the control command is C, which is taken as the input current range of the actuator not exceeding 200mA. max =200.

[0093] Optionally, in an embodiment of the present invention, the PID controller includes:

[0094] The proportional adjustment unit is used to proportionally adjust the deviation signal.

[0095] Specifically, the proportional adjustment unit can proportionally adjust the deviation signal of the system. Once the deviation occurs, the proportional adjustment unit will produce a control effect to reduce the deviation.

[0096] Integral adjustment unit: The integral adjustment unit is used to eliminate static error.

[0097] Specifically, the integral adjustment unit is mainly used to eliminate static error and improve the system's error-free degree. The strength of the integral action depends on the integral time constant. The larger the value of the integral time constant, the weaker the integral action, and vice versa.

[0098] Differential adjustment unit, the differential adjustment unit is used to adjust the deviation signal.

[0099] Specifically, the differential adjustment unit mainly reflects the change trend (change rate) of the deviation signal, and can introduce an effective early correction signal into the system before the deviation signal becomes too large, thereby speeding up the system's action speed and reducing the adjustment time.

[0100] In the embodiment of the present invention, through the simulation model of the PID controller, the frequency and voltage can be timely adjusted to near the expected value when the load continuously changes, thereby achieving the test purpose and verifying that the PID controller has good applicability to the governor-turbine model.

[0101] Optionally, in the embodiment of the present invention, the PID gain adjustment can refer to the following method: first gradually increase the proportional gain KP. If the response curve oscillates frequently, it is necessary to continue to increase KP; then, increase the integral link. If the curve is fluctuating and the fluctuation period is long, increase KI; if the curve has a convergence trend, but the fluctuation frequency is high, reduce the differential gain KD. According to this adjustment method, when KP = 500, KI = 100, KD = 50, the corresponding load is 50%, and the load is removed under the instruction of 50%, the power instruction output by the controller is as follows Figure 4 and Figure 5 As shown (where Figure 4 and Figure 5 The power in the figure uses the nominal value. For example, 0.8 in the figure is 80% of the rated power, and 1.0 is the rated power). It can be seen from the figure that under the adjustment parameters of this model, the power adjustment command given by the speed regulator is better.

[0102] refer to Figure 6 , which is a flow chart of an optional embodiment of a simulation method for a four-stroke turbocharged diesel generator set in a nuclear power plant provided by the present invention.

[0103] Among them, the simulation method of the four-stroke turbocharged diesel generator set of the nuclear power plant can be simulated based on the governor-turbine model of the four-stroke turbocharged diesel generator set of the nuclear power plant.

[0104] Specifically, Figure 6 As shown, the simulation method of the four-stroke turbocharged diesel generator set of the nuclear power plant includes the following steps:

[0105] Step S601 : The controller module 10 uses a preset algorithm to adjust parameters and outputs a control signal to the actuator module 20 .

[0106] Step S602 : The actuator module 20 establishes a relationship between the throttle angle of the diesel generator and the input current, and outputs a driving signal to the diesel engine module 30 according to the control signal output by the controller module 10 .

[0107] Step S603: the diesel engine module 30 establishes a functional relationship between the fuel injection amount and the output power of the diesel generator, and performs driving based on the functional relationship between the fuel injection amount and the output power of the diesel generator and the driving signal.

[0108] The governor-turbine model of the nuclear power plant four-stroke turbocharged diesel generator set in the embodiment of the present invention establishes an injection quantity-power model that matches the nuclear power plant four-stroke turbocharged diesel generator body through the functional relationship between the injection quantity and the output power of the diesel generator; adopts an inverse logic actuator, and through the relationship between the throttle angle of the diesel generator and the input current, a complex actuator module 20 model (i.e., an angle-current model) that can reflect the time domain performance is established. Through the analysis of the speed deviation, an output relationship of the diesel generator injection quantity control current information under the speed deviation is established, and a controller module 10 model based on the proportional integral differential control algorithm is established, thereby achieving matching with the unit performance and realizing dynamic simulation analysis of the nuclear power plant diesel generator set.

[0109] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0110] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0111] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0112] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A simulation system for a four-stroke turbocharged diesel generator set in a nuclear power plant, characterized in that: include: Governor-turbine model for a four-stroke turbocharged diesel generator set in a nuclear power plant; The governor-turbine model includes: a diesel engine module, an actuator module and a controller module; The controller module, the actuator module and the diesel engine module are connected in sequence; The controller module uses a preset algorithm to adjust parameters and output a control signal, amplifies the control signal through an amplification factor, subtracts the amplified control signal from the upper limit of the control instruction to obtain a control signal difference, and sends the control signal difference to the actuator module; The actuator module is an inverse logic actuator, which is used to establish the relationship between the throttle angle of the diesel generator and the input current, obtain the angle-current model, and output a drive signal to the diesel engine module according to the control signal output by the controller module; The diesel engine module is used to establish a functional relationship between the injection amount and the output power of the diesel generator based on the relationship between thermal energy and mechanical energy, obtain a fuel injection amount-power model, and perform driving based on the functional relationship between the injection amount and the output power of the diesel generator and the driving signal.

2. The simulation system of a four-stroke turbocharged diesel generator set in a nuclear power plant according to claim 1, characterized in that: The diesel engine module obtains the fuel injection amount-power model based on the functional relationship between the fuel injection amount and the output power of the diesel generator, including: According to the relationship between heat energy and mechanical energy, a functional relationship between fuel injection volume and diesel generator output power is established; Determine the delay time; According to the functional relationship between the delay time and the injection amount and the output power of the diesel generator, the diesel generator injection amount-power system transfer function is obtained; the diesel generator injection amount-power system transfer function is the injection amount-power model.

3. The simulation system of a four-stroke turbocharged diesel generator set in a nuclear power plant according to claim 1, characterized in that: The angle-current model is obtained according to the relationship between the throttle angle of the diesel generator and the input current, and includes: Get the relationship between the throttle angle and input current of the diesel generator; Determine the actuator's response time from current input to angle output change; The angle-current model is obtained according to the response time and the relationship between the throttle angle of the diesel generator and the input current.

4. The simulation system of a four-stroke turbocharged diesel generator set in a nuclear power plant according to claim 1, characterized in that: The controller module includes: a PID controller; The controller module uses a PID control algorithm based on the PID controller to adjust parameters and output the control signal.

5. The simulation system of the four-stroke turbocharged diesel generator set of a nuclear power plant according to claim 4, characterized in that: The PID controller comprises: A proportional adjustment unit, wherein the proportional adjustment unit is used to proportionally adjust the deviation signal; An integral adjustment unit, wherein the integral adjustment unit is used to eliminate static error; A differential adjustment unit, wherein the differential adjustment unit is used to adjust the deviation signal.

6. A simulation method for a four-stroke turbocharged diesel generator set in a nuclear power plant, characterized in that: The simulation method is based on a governor-turbine model of a four-stroke turbocharged diesel generator set in a nuclear power plant, and the simulation method comprises the following steps: The controller module uses a preset algorithm to adjust parameters and output a control signal, amplifies the control signal through an amplification factor, subtracts the amplified control signal from the upper limit of the control instruction to obtain a control signal difference, and sends the control signal difference to the actuator module; The actuator module of the inverse logic actuator establishes a relationship between the throttle angle of the diesel generator and the input current, obtains an angle-current model, and outputs a drive signal to the diesel engine module according to the control signal output by the controller module; The diesel engine module establishes a functional relationship between the injection amount and the output power of the diesel generator according to the relationship between thermal energy and mechanical energy, obtains a fuel injection amount-power model, and performs driving based on the functional relationship between the injection amount and the output power of the diesel generator and the driving signal.

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