Simulation Method and System of an Energy System Simulation Device

Abstract

An embodiment of the present invention relates to the field of electrical technology and discloses a simulation method for an energy system simulation device, including: constructing the energy system simulation device on a development platform; loading the simulation device into a real-time simulator; running the energy system simulation device on the real-time simulator to obtain grid-connected operation control parameters of the generator; and testing the physical circuit according to the grid-connected operation control parameters of the generator, where the physical circuit is the physical circuit of the energy system simulation device. The simulation method and system for the energy system simulation device in the present invention enable the verification of the grid connection algorithm for the physical circuit of the energy system and reduce the labor cost of repetitive tests.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of electrical technologies, and particularly to a simulation method and system for an energy system simulation device. Background Art

[0002] Currently, the grid-connected operation control parameters of generators in the energy system need to be obtained by testers through multiple debuggings, and multiple repetitive tests are required, which wastes a large amount of labor costs. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a simulation method and system for an energy system simulation device, so as to enable the verification of the grid connection algorithm of the physical circuit of the energy system and reduce the labor cost of repetitive tests.

[0004] To solve the above technical problems, an embodiment of the present invention provides a simulation method for an energy system simulation device. The energy system simulation device includes: at least two generator control loops, and each generator control loop includes: a generator and a controller connected to the generator. In each generator control loop, the output current of the generator is compared with the output voltage reference value after passing through a droop regulation module and fed back to the controller. The simulation method includes: constructing the energy system simulation device on a development platform; loading the simulation device into a real-time simulator; operating the energy system simulation device on the real-time simulator to obtain the grid-connected operation control parameters of the generator; and testing the physical circuit according to the grid-connected operation control parameters of the generator, where the physical circuit is the physical circuit of the energy system simulation device.

[0005] In addition, the step of operating the energy system simulation device on the real-time simulator to obtain the grid-connected operation control parameters of the generator includes: separately debugging each generator to obtain the first control single parameter of the controller connected to each generator; and verifying the grid connection algorithm for all the generators to obtain the second control parameter of the droop regulation module.

[0006] In addition, the step of separately debugging each generator to obtain the first control single parameter of the controller connected to each generator includes: inputting a first initial control parameter to the controller connected to each generator; and gradually debugging the initial control parameter so that the load characteristics of the generator under steady-state and transient conditions both meet the preset requirements to obtain the first control parameter.

[0007] In addition, verifying the grid connection algorithm for all the generators to obtain the second control parameter of the droop regulation module includes: inputting a second initial control parameter to the droop regulation module; debugging the second initial control parameter of the droop regulation module during the parallel connection of the motors, so that the grid-connected generators can achieve the grid connection current sharing effect within the load range after grid connection to obtain the second control parameter.

[0008] In addition, the physical circuit includes: a physical controller and multiple physical generators connected to the controller. The output end of each physical generator is connected to multiple loads of different sizes through a grid connection contactor, and the loads of the multiple physical generators are connected in parallel through a conversion contactor; testing the physical circuit according to the grid connection operation control parameter of the generator includes: performing a separate operation test on each physical generator according to the input of the first control single parameter; or, performing a grid connection test on all the generators according to the first control parameter and the second control parameter.

[0009] In addition, performing a separate operation test on each physical generator according to the input of the first control single parameter includes: controlling the conversion contactor to turn off, and respectively controlling the connection and disconnection of the load through the grid connection contactor of each physical generator, so as to perform a separate operation test on each physical generator according to the first control single parameter.

[0010] In addition, performing a grid connection test on all the generators according to the first control parameter and the second control parameter includes: controlling the conversion contactor to turn on, and controlling the connection and disconnection of the load through the grid connection contactors of the multiple physical generators, so as to perform a grid connection test on the multiple physical generators according to the first control parameter and the second control parameter.

[0011] Embodiments of the present invention also provide an energy system simulation system, including: a host computer, a lower computer emulator, an access device with an I / O module, a physical circuit, and a digital oscillograph, which are connected in sequence; the host computer is used to construct an energy system simulation device and send the energy system simulation device to the lower computer emulator. The energy system simulation device includes: two generator control loops, and each generator control loop includes: a generator and a controller connected to the generator. In each generator control loop, the output current of the generator passes through a droop regulation module and is compared with the output voltage reference value and then fed back to the controller; the lower computer emulator runs the energy system simulation device to obtain the grid-connected operation control parameters of the generator and feeds the grid-connected operation control parameters back to the physical circuit, and the physical circuit is the physical circuit of the energy system simulation device; the physical circuit tests according to the grid-connected operation control parameters of the generator and feeds the operation result back to the host computer, and the host computer is displayed through the digital oscillograph.

[0012] In addition, during the process of the lower computer emulator running the energy system simulation device, each generator is separately debugged to obtain the first control single parameter of the controller connected to each generator, and then, the grid connection algorithm of all generators is verified to obtain the second control parameter of the droop regulation module.

[0013] In addition, the physical circuit includes: a physical controller and a plurality of physical generators connected to the controller. The output end of each physical generator is connected to a plurality of loads of different sizes through a network connection contactor, and the loads of the plurality of physical generators are connected in parallel through a conversion contactor; the controller realizes the individual operation test of each physical generator according to the input of the first control single parameter, or the controller realizes the grid connection test of all generators according to the first control parameter and the second control parameter.

[0014] Embodiments of the present invention provide a simulation method for an energy system simulation device. First, an energy system simulation device is constructed on a development platform, and the energy system simulation device is run on a real-time simulator to obtain the grid-connected operation control parameters of the generator. To a certain extent, the effectiveness and possibility of the grid connection algorithm are verified through the full digital simulation method, and relatively appropriate grid-connected operation control parameters are simulated. Then, the physical circuit is tested according to the grid-connected operation control parameters of the generator, and the physical circuit is the physical circuit of the energy system simulation device, which reduces the labor cost of repetitive tests and increases the effectiveness and accuracy of the experiment. Description of the Drawings

[0015] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the drawings in the figures do not constitute a scale limitation.

[0016] Figure 1 is a schematic flow diagram of the simulation method of the energy system simulation device according to the present invention;

[0017] Figure 2 is the control system block diagram of the three - stage high - voltage DC generator according to the present invention;

[0018] Figure 3 is the overall simulation model of the generator controller according to the present invention;

[0019] Figure 4 is Figure 3 the internal model of the generator controller shown;

[0020] Figure 5 is Figure 4 the structure of the internal model shown including the protection module;

[0021] Figure 6 is Figure 5 the internal model of the protection module shown;

[0022] Figure 7 is the basic structure of the three - stage brushless synchronous high - voltage DC generator according to the present invention;

[0023] Figure 8 is the equivalent circuit of the non - salient - pole permanent - magnet generator according to the present invention;

[0024] Figure 9 is the circuit equivalent diagram of the salient - pole synchronous motor according to the present invention;

[0025] Figure 10 is the overall simulation model of the three - stage brushless synchronous high - voltage DC generator according to the present invention;

[0026] Figure 11 is Figure 10 the internal structure of the three - stage brushless synchronous high - voltage DC generator shown;

[0027] Figure 12 is the overall simulation model of the permanent - magnet generator according to the present invention;

[0028] Figure 13 is Figure 12 the internal structure of the permanent - magnet generator shown;

[0029] Figure 14 is Figure 12The model of the electrical angle and electrical angular velocity calculation module in the internal structure shown;

[0030] Figure 15 is Figure 12 The model of the back electromotive force calculation module in the internal structure shown;

[0031] Figure 16 is Figure 12 The module of the equivalent circuit model of the permanent magnet generator winding in the internal structure shown;

[0032] Figure 17 is Figure 12 The model of the dq-axis system conversion module in the internal structure shown;

[0033] Figure 18 Is the overall simulation model of the exciter according to the present invention;

[0034] Figure 19 is Figure 18 The internal structure of the exciter model shown;

[0035] Figure 20 is Figure 18 The model of the electrical angle and electrical angular velocity calculation module in the internal structure shown;

[0036] Figure 21 is Figure 18 The model of the coordinate transformation module from the ABC axis system to the dq axis system in the internal structure shown;

[0037] Figure 22 is Figure 18 The secondary exciter voltage and current calculation module in the internal structure shown

[0038] Figure 23 is Figure 18 The model of the coordinate transformation module from the dq-axis winding induced electromotive force to the ABC axis system in the internal structure shown;

[0039] Figure 24 is is Figure 18 The model of the module of the equivalent circuit model of the secondary exciter winding in the internal structure shown;

[0040] Figure 25 Is the overall simulation model of the main generator according to the present invention;

[0041] Figure 26 is Figure 24 The internal structure of the main generator shown;

[0042] Figure 27 is Figure 24 The equivalent circuit model of the main generator winding in the internal structure shown;

[0043] Figure 28is the external characteristic curve of the generator according to the present invention;

[0044] Figure 29 is the schematic diagram of the parallel control algorithm according to the present invention;

[0045] Figure 30 is the modeling of the parallel flow control algorithm model according to the present invention;

[0046] Figure 31 is the modeling of the overall energy system simulation device according to the present invention;

[0047] Figure 32 is the generator parallel control model according to the present invention;

[0048] Figure 33 is the verification waveform diagram of the grid - connection algorithm according to the present invention;

[0049] Figure 34 is the structural schematic diagram of the energy system simulation system according to the present invention. Specific Embodiments

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will elaborate on each embodiment of the present invention with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of the present invention, many technical details are provided to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0051] The first embodiment of the present invention relates to a simulation method of an energy system simulation device. The core of this embodiment is that the energy system simulation device includes: at least two generator control loops, and each generator control loop includes: a generator and a controller connected to the generator. In each generator control loop, the output current of the generator is compared with the output voltage reference value after passing through a droop - regulation module and fed back to the controller. The simulation method includes: constructing the energy system simulation device on a development platform; loading the simulation device into a real - time simulator; running the energy system simulation device on the real - time simulator to obtain the grid - connection operation control parameters of the generator; and testing the physical circuit according to the grid - connection operation control parameters of the generator, where the physical circuit is the physical circuit of the energy system simulation device.

[0052] In this embodiment, the effectiveness and feasibility of the grid - connection algorithm are verified to a certain extent through full - digital simulation, and relatively appropriate grid - connection operation control parameters are simulated. Then, the physical circuit, which is the physical circuit of the energy system simulation device, is tested according to the grid - connection operation control parameters of the generator, reducing the labor cost of repetitive experiments and increasing the effectiveness and accuracy of the experiments.

[0053] The implementation details of the simulation method of the energy system simulation device of this embodiment will be specifically described below. The following content is only the implementation details provided for easy understanding and is not necessary for implementing this solution.

[0054] The flow chart of the simulation method of the energy system simulation device in this embodiment is as Figure 1 shown:

[0055] Step S11: Build an energy system simulation device on the development platform.

[0056] Step S12: Load the simulation device into the real-time simulator.

[0057] Step S13: Run the energy system simulation device on the real-time simulator to obtain the grid-connected operation control parameters of the generator.

[0058] Step S14: Test the physical circuit according to the grid-connected operation control parameters of the generator. The physical circuit is the physical circuit of the energy system simulation device.

[0059] First of all, the energy system simulation device in this embodiment includes: a generator model, a generator controller model, and a grid connection algorithm model. These models are developed and used based on the RT-LAB and Matlab / Simulink platforms. The energy system in this embodiment can be an aircraft energy system.

[0060] (1) Generator controller model

[0061] The generator controller is an important part of the energy generation system, which is used to control the output voltage of the power generation system to have good steady-state and dynamic qualities.

[0062] The generator controller assembled on the high-voltage DC generator realizes the output voltage control by adjusting the excitation current of the three-stage high-voltage DC generator. The typical control system frame is as Figure 2 shown. The key of the generator controller is to adjust the excitation current in real time according to the change of the output voltage, and finally stabilize the output voltage within the required range. The entire power generation adjustment link includes the excitation current main power circuit, PWM comparator or generator, overvoltage protection, and load current limit and protection module, etc. When performing single-generator control, the controller adopts single-voltage loop control. When performing generator grid connection tests, grid connection algorithm control is adopted for the excitation current.

[0063] The simulation model of the generator controller:

[0064] Build the overall simulation model of the generator controller, as Figure 3 shown. It includes 15 ports, of which 10 are signal ports and 5 are electrical ports. The functions of each port are as follows:

[0065] The input port ALC is a control port. When the input signal is "1" when the status of ALC is detected at this port, the generator controller adopts a parallel algorithm model; when the input signal is "0" when the status of ALC is detected at the port, the single generator output is controlled for voltage regulation; the input port udc is the access end before the grid-connected contactor; the input port Io_B is the access end of the output current sensing line of the currently controlled generator; the input port Io_ALL is the access end of the current sensing line of the total load; the input port Io_B is the access end of the output current sensing line of another controlled generator; the input terminal Rst is the reset port of the generator controller, with 1 rising edge transition to reset the generator controller; the input terminal Gs is the enable control port of the generator. When the input signal detected at this port is "0", the generator controller controls the excitation current of the generator to be 0 and the output voltage to be 0; when it is "1", the generator controller starts the generator output for voltage regulation; the output port DLC Ctrl is the control port of the grid-connected contactor for the generator output; the output port m is the status measurement port of the generator controller, providing measurement values such as the protection signal of the generator controller; in the electrical ports, "FA", "FB", "FC" are the three-phase power output interfaces of the permanent magnet machine; in the electrical ports, "F+", "F-" are the excitation winding interfaces. The output port is a PWM drive waveform for outputting a PWM wave to control the excitation of the generator.

[0066] The internal model of the generator controller is as follows Figure 4 As shown, where Three-Phase Breaker is a contactor for controlling the on / off of the three-phase output of the permanent magnet machine; Bridge is a three-phase uncontrolled rectifier bridge model for rectifying the three-phase voltage output of the permanent magnet machine; 2-Level TSB is the power circuit of the excitation winding, establishing models of mosfet and freewheeling diodes; regulator is a voltage regulation and protection module, and Multiport Switch is a change-over switch for controlling the generation and shutdown of PWM of the generator.

[0067] The internal model of Regulator mainly includes two discrete PI controllers to achieve voltage loop and current sharing closed-loop control. When controlling a single generator, a single voltage loop is used for control. When conducting grid-connected tests, a current sharing loop is added to control the balanced output load of multiple grid-connected devices. After the controller finally outputs a controllable duty cycle, a 2kHz PWM wave is generated through the SPWM production module in the RT-Envents module library to drive the Mosfet.

[0068] Figure 5 In addition to the control parts of the voltage loop and current sharing loop, the model also has an important protection module, namely the Protect module. The internal model of the protection module Protect is as Figure 6As shown, the functions of multi-load uneven current protection, overcurrent protection for each load, inverse-time overvoltage protection for the output voltage, and closing control of the grid-connected contactor DLC are implemented successively from top to bottom.

[0069] For the overcurrent and overvoltage protection parts, a comparator is used respectively to compare with the corresponding threshold values. After a certain preset time, the comparison results are respectively input to the set end of an SR flip-flop, and the!Q output ends of the two SR flip-flops are AND-operated to obtain the protection signal.

[0070] Under normal circumstances, both the voltage and current are within the protection thresholds. The!Q output end of the SR flip-flop is high, and the result after AND operation is 1, indicating that the current state is normal and there is no protection. When an overcurrent or overvoltage state occurs, the output of the comparator changes from low to high, and the!Q output end of the SR flip-flop changes to low. If any!Q end is low, it will cause the AND result to be 0, thus generating a protection signal.

[0071] The control signal of the grid-connected contactor DLC is not only related to the protection logic but also controlled by the internal voltage logic of the generator. When the Q output end of the SR flip-flop is 1, that is, there is no protection, and the command signal for generator power supply (represented by a high level, "1" signal) DLC_con jumps to 1, DLC will close. Before DLC_con jumps to 1, the generator controller will judge whether the output voltage of the generator reaches 270V and lasts for a certain time before making DLC_con output a 1 signal. The specific voltage judgment and delay process are carried out by the Relay module and the ON Delay module, and the specific delay time can be set.

[0072] The parameters of the generator controller model include: overvoltage protection setting, voltage protection reference value, inverse-time curve voltage protection multiple, voltage inverse-time protection time, generator overcurrent protection setting (using single-point inverse-time protection).

[0073] Measures for increasing current sharing protection for grid-connected generators: Under normal single-generator control, current sharing protection is not carried out. When grid-connected power supply is carried out, uneven current protection is carried out, and the threshold value of uneven current protection can be set.

[0074] (2) Generator model

[0075] The generator model is used to verify the control algorithm of a single generator and conduct full-digital simulation research on the load balancing control strategy during grid connection, providing experimental guidance for semi-physical RCP verification.

[0076] The basic structure of a three-stage brushless synchronous high-voltage DC generator is as Figure 7As shown in the figure, compared with ordinary synchronous motors, the three-stage brushless synchronous HVDC generator eliminates slip rings, has high reliability and simple maintenance, and is widely used as a primary power source in aviation and ship propulsion systems. This generator consists of a main generator, an exciter, a rotating rectifier, and a permanent magnet sub-exciter. The main generator is a salient-pole rotating magnetic pole type synchronous motor with a damping winding on the rotor; the exciter is a rotating armature type synchronous motor, with the excitation winding installed on the stator and the armature winding installed on the rotor; the armature winding of the exciter is connected to the excitation winding of the main generator through a rotating rectifier; the sub-exciter is a rotating magnetic pole type permanent magnet generator that supplies power to the control circuit and the excitation circuit of the exciter.

[0077] The body structure of the three-stage brushless synchronous HVDC generator can be divided into three parts: a permanent magnet generator (sub-exciter), a rotating armature type synchronous motor (exciter), and a rotating magnetic pole type synchronous motor (main generator). When establishing a real-time simulation model, these three parts are modeled separately, so it is necessary to introduce their respective mathematical models.

[0078] The mathematical model of the permanent magnet generator (sub-exciter) is as follows:

[0079] (1) Voltage and current balance equations

[0080] In the ABC three-phase coordinate system, with the positive directions of voltage and current defined according to the generator convention, the equivalent circuit of the non-salient pole permanent magnet generator is as shown in Figure 8 shown, Figure 8 where N is the neutral point of the motor.

[0081] According to the equivalent circuit diagram shown in Figure 8 the three-phase voltage and current balance equations of the permanent magnet generator are as shown in formula (1) below:

[0082]

[0083] where: Ua, Ub, Uc - phase voltages of the motor stator windings, in V; ia, ib, ic - phase currents of the motor stator windings, in A; ea, eb, ec - counter electromotive forces of the motor armature windings, in V; L - inductance of each phase winding (equal to the difference between the self-inductance and mutual inductance of the winding), in H; the magnitude of the armature counter electromotive force of the permanent magnet generator is related to the magnetic flux per pole and the rotational speed. If the magnetic flux per pole Φδ remains constant at Φδm, let K = CeΦδm, then the counter electromotive force of the permanent magnet generator is proportional to the rotational speed. Therefore, the armature counter electromotive force e of the permanent magnet generator can be expressed by the following formula (2):

[0084]

[0085] Where: Ee——the back electromotive force of a sine wave with an amplitude of 1, which is only related to the electrical angle of the rotor, unit: V; ω——the mechanical angular velocity of the motor, unit: rad / s; n——the rotational speed of the motor, unit: r / min; Ke——the back electromotive force coefficient of the motor; θe——the electrical angle, unit: rad / s.

[0086] (2) Conversion between electrical angular velocity and mechanical speed

[0087] Since the rotor of a permanent magnet generator is usually multi-pole, there is a proportional relationship between its mechanical angular velocity and electrical angular velocity, which can be expressed by the following formula (3):

[0088]

[0089] Where: p——the number of rotor pole pairs of the brushless DC motor; ωe——the electrical angular velocity, rad / s; n——the rotational speed, r / min.

[0090] (3) Electrical angle calculation

[0091] The electrical angle of a permanent magnet generator can be obtained by integrating the electrical angular velocity and can be expressed by the following formula (4):

[0092]

[0093] Where: s——the Laplace operator; ωe——the electrical angular velocity; θe——the electrical angle, rad / s.

[0094] Mathematical model of rotating magnetic pole type synchronous motor (main generator)

[0095] The Figure 9 following is the equivalent circuit diagram of a salient pole synchronous motor, where u, i, Φ, e represent the voltage, current, magnetic flux, and back electromotive force of each winding respectively, and the subscripts a, b, c and f, D, Q represent the stator a, b, c axis armature windings and the rotor field winding, D-axis damper winding, and Q-axis damper winding respectively. The positive directions of the current, voltage, and magnetic flux of each winding specified in this model are marked in the figure.

[0096] (1) Coordinate transformation formula

[0097] According to the coordinate transformation principle, transform the ABC coordinate system to the dq synchronous rotating coordinate system. In the dq synchronous rotating coordinate system, the q-axis leads the d-axis by 90°, and the electrical angle θe is the angle between the d-axis and the a-phase axis. The transformation matrix formula is formula (5):

[0098]

[0099] The transformation formula for transforming the dq synchronous rotating coordinate system to the ABC coordinate system is formula (6):

[0100]

[0101] Based on the above coordinate transformation formula, the mathematical model of the salient-pole synchronous machine in the dq coordinate system can be obtained, including the flux linkage equation and the voltage equation:

[0102] (2) Flux linkage equation [1]

[0103] ψ d = L ls i d + L md (i d + i′ f + i′ kd )

[0104] ψ q = L ls i q + L mq (i q + i′ kq )

[0105] ψ′ fd = L′ lf i′ f + L md (i d + i′ f + i′ kd )

[0106] ψ′ kd = L′ lkd i′ kd + L md (i d + i′ f + i′ kd )

[0107] ψ′ kq = L′ lkq i′ kq + L mq (i q + i′ kq ) (7)

[0108] In the formula, the current and flux linkage parameters of the field winding and the direct and quadrature axis damper windings with superscript ′ indicate that the value is the result of being converted to the stator side. The definitions of the variables and subscripts in the formula are:

[0109] Ψ - Flux linkage

[0110] L - Inductance

[0111] i - Current

[0112] d, q - d-axis and q-axis variables

[0113] R, s - Rotor and stator variables

[0114] l, m - Leakage inductance and magnetizing inductance variables

[0115] f, k - Excitation winding and damper winding variables

[0116] (3) Voltage equation

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] Wherein, the parameters of the excitation winding and the direct and quadrature axis damper windings are the results converted to the stator side. The definitions of the variables and subscripts in the formula are as follows:

[0123] u - Voltage

[0124] R - Resistance

[0125] ωe - Electrical angular velocity

[0126] (4) Direct and quadrature axis mutual inductance flux linkages

[0127] Further defined as Ψmd direct axis mutual inductance flux linkage and Ψmq quadrature axis mutual inductance flux linkage, and their expressions are given by Equation (9):

[0128] ψ md =L md (i d +i′ f +i′ kd )

[0129] ψ mq =L mq (i q +i′ kq ) (9)

[0130] Then the flux linkage equations of the excitation winding and the direct and quadrature axis damper windings given by Equation (7) can be simplified to Equation (10):

[0131] ψ′ fd =L′ lf i′ f +ψ md

[0132] ψ′ kd =L′ lkd i′ kd +ψmd

[0133] ψ′ kq = L′ lkq i′ kq + ψ mq (10)

[0134] According to the above formula, the calculation formulas for the field current and the direct and quadrature axis damper winding currents are shown in Equation (11):

[0135]

[0136]

[0137]

[0138] Substitute the field current and the direct and quadrature axis damper winding currents expressed by Equation (11) into Equation (9), and after combining the like terms containing ψ md 、ψ mq the following result is obtained:

[0139]

[0140]

[0141] In the formula

[0142]

[0143]

[0144] Substitute Equation (12) into the first two equations of Equation (7), and another expression for the direct and quadrature axis flux linkages is obtained as:

[0145]

[0146]

[0147] (21) Mathematical Model of Rotating Armature Type Synchronous Machine (Exciter)

[0148] Both the exciter and the main generator are salient pole synchronous generators, and the air-gap magnetic fields are both sinusoidally distributed. The only difference between them is that: there is no damper winding on the poles of the exciter; while there are direct axis damper windings and quadrature axis damper windings installed on the poles of the main machine. Therefore, the mathematical model of the exciter is the same as that of the main generator. By simplifying the direct and quadrature axis damper winding terms in the mathematical model of the main generator, the mathematical model of the exciter can be obtained.

[0149] (22) Simulation Model of Three-Stage Brushless Synchronous High-Voltage DC Generator

[0150] The overall simulation model of the three-stage brushless synchronous high-voltage DC generator is as followsFigure 10 As shown in the figure, the input is the motor speed n (r / min), and the outputs m1, m2, and m3 are the voltage, current and other parameters of the permanent magnet generator (sub-exciter), rotating armature synchronous motor (exciter), and rotating magnetic pole synchronous motor (main generator); FA, FB, and FC are the three-phase output ports of the permanent magnet machine, F+ and F- are the excitation winding ports, and Uo and GND ports are the DC output ports after rectification of the three-phase output of the main generator.

[0151] The internal structure of the three-stage brushless synchronous high-voltage DC generator is as follows Figure 11 As shown in the figure, it includes a permanent magnet generator (sub-exciter), a rotating armature synchronous motor (exciter), a rotating magnetic pole synchronous motor (main generator), a rotating rectifier bridge (Bridge), a main generator output rectifier bridge (Bridge1, Bridge2), an output filter circuit and other main components.

[0152] The modeling of each main component will be described in detail respectively.

[0153] Permanent magnet generator (sub-exciter) simulation model

[0154] The overall simulation model of the permanent magnet generator is as follows Figure 12 As shown in the figure, the input is the motor speed n (r / min), and the outputs are the motor voltage, current and other parameters. The A, B, and C ports are the electrical connection ends of the three-phase armature winding of the motor.

[0155] Figure 12 The internal structure of the permanent magnet generator (sub-exciter) shown in the figure is as follows Figure 13 As shown in the figure, it includes an electrical angle and electrical angular velocity calculation module (w&angle), a back electromotive force calculation module (eabc) of the permanent magnet generator (sub-exciter), a winding equivalent circuit model module (Coil) of the permanent magnet generator (sub-exciter), and a dq-axis system conversion module (abc2dq) and other four main components.

[0156] The input of the electrical angle and electrical angular velocity calculation module (w&angle) is the motor speed n (r / min), and the outputs theta (rad) is the electrical angle, we (rad / s) is the electrical angular velocity, and f (Hz) is the frequency.

[0157] The model of the electrical angle and electrical angular velocity calculation module (w&angle) is as follows Figure 14 As shown in the figure, it realizes the calculations of equations (3) and (4).

[0158] The inputs of the back electromotive force calculation module (eabc) of the permanent magnet generator (pilot exciter) are we (electrical angular velocity) and theta (electrical angle), and the output eabc is the three-phase back electromotive force. This module calculates the three-phase back electromotive force based on Equation (2), and the model is as follows Figure 15 as shown

[0159] As Figure 16 shown, the inputs of the equivalent circuit model module (Coil) of the permanent magnet generator (pilot exciter) winding are eabc (three-phase back electromotive force); the outputs uabc and iabc are the three-phase phase voltages and phase currents. A, B, and C are the electrical connection terminals of the three-phase armature windings, and N is the neutral point of the motor. The model is established based on the equivalent circuit diagram of the permanent magnet generator, and the positive directions of the voltage and current are consistent with the figure, and it is modeled according to the positive direction convention of the generator

[0160] The dq-axis system conversion module (abc2dq) realizes the coordinate transformation of the three-phase voltage and three-phase current from the ABC axis system to the dq axis system. The model is as Figure 17 shown

[0161] Parameter settings of the permanent magnet generator (pilot exciter)

[0162] The parameter settings of the permanent magnet generator (pilot exciter) include: the air-gap magnetic flux generated by the permanent magnet, unit Wb, the electrical parameters of the three-phase windings of the permanent magnet generator, the mechanical parameters of the permanent magnet generator, the moment of inertia, the friction coefficient, and the number of pole pairs

[0163] Simulation model of the rotating armature type synchronous motor (exciter)

[0164] The overall simulation model of the exciter is as follows Figure 18 shown. The input is the motor speed n (r / min), and the outputs are motor voltage, current and other parameters. The A, B, and C ports are the electrical connection terminals of the three-phase armature windings of the motor, and F+ and F- are the connection terminals of the excitation winding

[0165] Figure 18 The internal structure of the pilot exciter model shown in Figure 19 is shown, including the electrical angle and electrical angular velocity calculation module (w&angle), the axis system conversion modules (abc2dq, dq2abc) between the dq coordinate and the ABC coordinate, the pilot exciter voltage and current calculation module (i to u), the pilot exciter winding equivalent circuit model module (Coil) and other main components

[0166] The input of the electrical angle and electrical angular velocity calculation module (w&angle) is the motor speed n (r / min), and the outputs are theta (rad) (electrical angle), we (rad / s) (electrical angular velocity), and f (Hz) (frequency)

[0167] The model of the electrical angle and electrical angular velocity calculation module (w&angle) is as follows Figure 20 As shown, the calculations in equations (3) and (4) are implemented.

[0168] The abc2dq module implements the coordinate transformation of three-phase voltages and three-phase currents from the ABC axis system to the dq axis system. The model is as follows Figure 21 As shown, Figure 21 The calculation of uf at the bottom in [figure] converts the field winding voltage to the armature winding side.

[0169] The input udq and idq of the auxiliary exciter voltage and current calculation module (i to u) are the dq axis components of the armature voltage and current, uf' is the excitation voltage, and we is the electrical angular velocity; the outputs are if' as the excitation current, and ed and eq as the d-axis and q-axis induced electromotive forces. The model is as follows Figure 22 As shown.

[0170] The dq2abc module implements the coordinate transformation of the dq axis winding induced electromotive force to the ABC axis system, and at the same time converts the converted value of the excitation current into the actual excitation current value. The model is as follows Figure 23 As shown.

[0171] As Figure 24 shown, the input eabc of the auxiliary exciter winding equivalent circuit model module (Coil) is the three-phase back electromotive force, and if is the excitation current; the outputs uabc, iabc are the three-phase phase voltages and phase currents, and uf is the field winding voltage. A, B, and C are the electrical connection terminals of the three-phase armature windings, N is the neutral point of the motor, and F+, F- are the connection terminals of the field winding. The model is established based on the auxiliary exciter equivalent circuit and is modeled according to the positive direction convention of the motor.

[0172] Rotating armature type synchronous motor (exciter) parameter settings

[0173] The exciter parameters include: rated power, rated line voltage effective value, rated frequency, rated excitation current, electrical parameters of the exciter three-phase windings, electrical parameters of the exciter field winding, mechanical parameters of the permanent magnet generator, moment of inertia, friction coefficient, number of pole pairs.

[0174] Rotating field type synchronous motor (main generator) simulation model

[0175] The overall simulation model of the main generator is as follows Figure 25 As shown. The input is the motor speed n (r / min), and the outputs are motor voltage, current and other parameters. The A, B, C ports are the electrical connection terminals of the motor three-phase armature windings, and F+, F- are the connection terminals of the field winding. Its internal structure is as Figure 26 shown, where Figure 26 the main generator winding equivalent circuit model in [figure] is as Figure 27 shown.

[0176] The inputs of the equivalent circuit model module (Coil) of the main generator winding are eabc, the three-phase back electromotive force, and if, the excitation current; the outputs are uabc and iabc, the three-phase phase voltages and phase currents, and uf, the excitation winding voltage. A, B, and C are the electrical connection terminals of the three-phase armature winding, N is the neutral point of the motor, and F+ and F- are the connection terminals of the excitation winding. The model is established based on the equivalent circuit of the main generator and is modeled according to the positive direction convention of the motor.

[0177] The parameters of the rotating-pole synchronous motor (main generator) include: rated power, rated effective line voltage, rated frequency, rated excitation current, electrical parameters of the three-phase windings of the main generator, electrical parameters of the excitation winding of the main generator, electrical parameters of the damper winding of the main generator, mechanical parameters of the permanent magnet generator, moment of inertia, friction coefficient, and number of pole pairs.

[0178] Build the full digital simulation model of the generator as described above.

[0179] (3) Grid connection algorithm model

[0180] In power systems, microgrids, and ship power systems, multiple generators are involved in parallel connection. For the distribution of active loads, it is usually adjusted through the voltage - power droop characteristic. Therefore, when generators need to be connected in parallel, the DC output power of the generator and the droop coefficient need to be introduced in the comparison link between the voltage reference value and the actual value to obtain the voltage reference value under the corresponding load condition, and subtract it from the actual value of the DC side voltage fed back.

[0181] ΔU dc =U ref -K f ×P-U dc (15)

[0182] Among them, U ref is the reference voltage, P is the load power, and K f is the droop coefficient.

[0183] The essence of the above algorithm is to use the current feedback signal of this module or directly connect a resistor in series at the output end to make the slopes of the external characteristics tend to be the same by changing the output resistance of the module unit, so as to achieve current sharing.

[0184] This solution uses the current feedback signal of this module to make the external characteristics tend to be the same, that is, by selecting different injection points of the current feedback signal, the reference voltage of the controller is corrected to change the reference to change the external characteristic curves corresponding to each channel. As can be seen from the above Figure 28 It can be seen that the two output voltages Vo1 and Vo2 are different. By adjusting the reference voltage to make the external characteristics the same (the current reaches the current sharing state Io), the smaller the difference in the voltage reference values, the better the current sharing effect.

[0185] The principle of its parallel control algorithm is as followsFigure 29 As shown, after adjusting the output voltage external characteristic through the average value droop algorithm (the current given for each path is calculated by the average current of all branches), the PWM control for each path is completed through the voltage and current controllers, thereby achieving the current sharing effect.

[0186] According to the above principle of the average value current sharing algorithm, the parallel current control algorithm model is built as follows Figure 30 As shown. Thus, the modeling of the overall energy system simulation device is as follows Figure 31 As shown.

[0187] After obtaining the energy system simulation device, the simulation device is loaded onto the real-time simulator, and the grid-connected operation control parameters of the generator are obtained by running the energy system simulation device on the real-time simulator; the physical circuit is tested according to the grid-connected operation control parameters of the generator, and the physical circuit is the physical circuit of the energy system simulation device.

[0188] The physical circuit of the energy system simulation device, that is, the generator parallel control model is as follows Figure 32 As shown, the physical circuit includes: a plurality of physical generators connected to the entity controller, the output end of each physical generator is connected to a plurality of different-sized loads through the grid-connected contactors DLC1 and DLC2, and the loads of the plurality of physical generators are connected in parallel through the transfer contactor ALC.

[0189] Optionally, obtaining the grid-connected operation control parameters of the generator by running the energy system simulation device on the real-time simulator includes: separately debugging each generator to obtain the first control single parameter of the controller connected to each generator; verifying the grid connection algorithm for all generators to obtain the second control parameter of the droop regulation module.

[0190] Optionally, separately debugging each of the generators to obtain the first control single parameter of the controller connected to each of the generators includes: inputting the first initial control parameter to the controller connected to each of the generators; gradually debugging the initial control parameter so that the load characteristics of the generator under steady-state and transient conditions both meet the preset requirements to obtain the first control parameter.

[0191] Optionally, verifying the grid connection algorithm for all generators to obtain the second control parameter of the droop regulation module includes: inputting the second initial control parameter to the droop regulation module; debugging the second initial control parameter of the droop regulation module when the motors are in parallel so that the grid-connected generators can achieve the grid-connected current sharing effect within the load range to obtain the second control parameter.

[0192] Specifically, in the generator grid connection experiment of the energy system experiment, the algorithm model can be established according to the above droop characteristics. Verify whether the grid connection strategy and architecture can meet the requirements of preliminary research in full digital simulation, and gradually complete the parallel parameter debugging under actual working conditions during the actual verification process. In full digital simulation, first debug a single generator, and then verify the grid connection algorithm. A single generator is controlled by a single voltage loop, and the PI parameters of the single voltage loop are gradually debugged to make the load characteristics of the generator meet the relevant requirements of GJB181A under steady-state and transient conditions, so as to obtain the first control parameter; after the single generator debugging is completed, a parallel test of two generators is carried out. At this time, the controller of the single generator is no longer changed. By debugging the PI parameters of the current sharing controller during parallel connection, the grid-connected generators can achieve the grid connection current sharing effect within the load range, so as to obtain the second control parameter.

[0193] After verification by full digital simulation, the control algorithm is feasible and the control effect simulation meets the expected requirements. Test case: Initially, one generator is loaded with 50A and the other is unloaded. After grid connection, it is quickly adjusted to the current sharing state. At this time, a large load of 300A is applied, and the grid connection algorithm model can still adjust the two channels to the same output power. Moreover, the greater the load power, the better the grid connection current sharing effect. The results are as Figure 33 shown.

[0194] Optionally, test the physical circuit according to the grid connection operation control parameters of the generator, including: realizing the individual operation test of each physical generator according to the input of the first control single parameter; or, realizing the grid connection test of all generators according to the first control parameter and the second control parameter.

[0195] Optionally, the individual operation test of each physical generator according to the input of the first control single parameter includes: controlling the conversion contactor to turn off, and respectively controlling the load to turn on and off through the grid connection contactors of each physical generator, so as to conduct the individual operation test of each physical generator according to the first control single parameter.

[0196] Optionally, realizing the grid connection test of all generators according to the first control parameter and the second control parameter includes: controlling the conversion contactor to turn on, and controlling the load to turn on and off through the grid connection contactors of multiple physical generators, so as to conduct the grid connection test of multiple physical generators according to the first control parameter and the second control parameter.

[0197] Specifically, under normal conditions (with a small-power load), the two generators respectively control the connection and disconnection of the load through their respective grid-connection contactors DLC1 and DLC2. At this time, the transfer contactor ALC is disconnected, and each generator controller uses a single-unit excitation control algorithm. There are two cases for control in the parallel connection situation. One case: when a large-power load needs to be connected, the upper computer sends a control instruction, and the real-time model of the simulator receives the control-end instruction to turn on the transfer contactor ALC, and controls the operation of the two generators through the average droop control algorithm. In the other case, when the ALC control instruction from the upper computer is not received, if the power of a single load exceeds 80% (modified according to the actual situation during the experiment), the parallel algorithm automatically controls the transfer contactor ALC to open, and at this time, the parallel control is automatically enabled when the state of the auxiliary contact of ALC is detected.

[0198] The embodiments of the present invention bring the following beneficial effects: Through the way of hardware-in-the-loop simulation, the multi-source grid-connection technology and the large-power load impact suppression technology are verified; through the way of full digital simulation, the effectiveness and possibility of the grid-connection algorithm are verified to a certain extent, a more appropriate PID parameter is simulated, the labor cost of repetitive experiments is reduced, and the effectiveness and accuracy of the experiment are increased; through the way of testing with the hardware-in-the-loop simulation system, the test cycle is shortened, and the experiment of controlling the grid connection of two generators and the experiment of large-power load impact suppression are completed without modifying the generator controller.

[0199] The step division of the above various methods is only for clear description. When implemented, they can be combined into one step or some steps can be split into multiple steps. As long as the same logical relationship is included, they are all within the protection scope of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs, but not changing the core design of its algorithm and process are all within the protection scope of this patent.

[0200] The embodiments of the present invention also provide an energy system simulation system. See Figure 34, including a host computer, a lower computer emulator, an access device with an I / O module, a physical circuit, and a digital oscillograph connected in sequence; the host computer is used to construct an energy system simulation device and send the energy system simulation device to the lower computer emulator. The energy system simulation device includes: two generator control loops, and each generator control loop includes: a generator and a controller connected to the generator. In each motor control loop, the output current of the generator is compared with the output voltage reference value through a droop regulation module and then fed back to the controller; the lower computer emulator runs the energy system simulation device to obtain the grid-connected operation control parameters of the generator and feeds the grid-connected operation control parameters back to the physical circuit, and the physical circuit is the physical circuit of the energy system simulation device; the physical circuit tests according to the grid-connected operation control parameters of the generator and feeds the operation result back to the host computer, and the host computer displays it through the digital oscillograph.

[0201] Specifically, this experimental system consists of four layers, including:

[0202] (1) Development and monitoring subsystem

[0203] This subsystem consists of 1 development host computer, and the real-time simulation support platform software is RT-LAB, which mainly completes functions such as energy system model development, energy management emulator software module development, main control device software module development, simulation test management and operation, online parameter adjustment, curve display, data monitoring, function test and verification, and data analysis.

[0204] (2) Real-time operation subsystem

[0205] This subsystem is the target machine system, consisting of 1 OP5600 real-time target machine, which is the core part of the whole system, has a Linux real-time operating system, and completes system mathematical model operations (energy system real-time model) and real-time I / O communication.

[0206] (3) Signal interface subsystem

[0207] This subsystem is the interface with the real system, consisting of a signal conditioning box, which mainly completes signal conditioning and interface adaptation functions, and completes the physical signal connection between each subsystem and physical devices.

[0208] (4) Physical devices of the energy system

[0209] Physical devices required for the semi-physical simulation experiment of the energy system, including generators, contactors, sensors, power supplies, cables, etc.

[0210] This embodiment conducts a semi-physical simulation experiment of the energy system on the basis of the existing software and hardware platform of the "power supply system semi-physical simulation equipment". The experiment mainly conducts tests and verifications on multi-source grid connection technology and high-power load impact suppression technology.

[0211] Based on the existing software and hardware platform of the "power supply system hardware-in-the-loop simulation device", physical devices such as generators, loads, and energy storage used in the experiment are connected to conduct the hardware-in-the-loop simulation experiment of the energy system. The experiment mainly conducts tests and verifications on multi-source grid connection technologies.

[0212] An embodiment of the present invention also provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the simulation method of the above energy system simulation device is implemented.

[0213] That is, those skilled in the art can understand that all or part of the steps in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a program. This program is stored in a storage medium and includes several instructions to enable a device (which can be a single-chip microcomputer, a chip, etc.) or a processor to execute all or part of the steps of the methods described in various embodiments of the present application. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs and other various media that can store program codes.

[0214] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made in form and details without departing from the spirit and scope of the present invention.

Claims

1. A simulation method for an energy system simulation device, characterized in that, the energy system simulation device includes: at least two generator control loops, each of the generator control loops includes: a generator model, a controller model connected to the generator model, and in each of the generator control loops, the output current of the generator model is compared with the output voltage reference value after passing through a droop regulation module and fed back to the controller model; the simulation method includes: constructing the energy system simulation device on a development platform; loading the energy system simulation device onto a real-time simulator; operating the energy system simulation device on the real-time simulator to obtain grid-connected operation control parameters of the generator model; testing a physical circuit according to the grid-connected operation control parameters of the generator model, where the physical circuit is the physical circuit of the energy system simulation device; the physical circuit includes: a physical controller, a plurality of physical generators connected to the physical controller, the output end of each physical generator is connected to a plurality of loads of different sizes through a network connection contactor, and the loads of the plurality of physical generators are connected in parallel through a conversion contactor.

2. The simulation method for the energy system simulation device according to claim 1, characterized in that, the operating the energy system simulation device on the real-time simulator to obtain grid-connected operation control parameters of the generator model includes: separately debugging each of the generator models to obtain first control parameters of the controller model connected to each of the generator models; verifying the grid connection algorithm for all the generator models to obtain second control parameters of the droop regulation module.

3. The simulation method for the energy system simulation device according to claim 2, characterized in that, the separately debugging each of the generator models to obtain first control parameters of the controller model connected to each of the generator models includes: inputting first initial control parameters to the controller model connected to each of the generator models; gradually debugging the first initial control parameters so that the load characteristics of the generator model under steady-state and transient conditions both meet preset requirements to obtain the first control parameters.

4. The simulation method for the energy system simulation device according to claim 2, characterized in that, the verifying the grid connection algorithm for all the generator models to obtain second control parameters of the droop regulation module includes: inputting second initial control parameters to the droop regulation module; debugging the second initial control parameters of the droop regulation module when the motors are in parallel so that the grid-connected generator models can achieve grid connection and current sharing effects within the load range to obtain the second control parameters.

5. The simulation method for the energy system simulation device according to claim 2, characterized in that, the testing the physical circuit according to the grid-connected operation control parameters of the generator model includes: performing separate operation tests for each of the physical generators according to the input of the first control parameters; or, performing grid connection tests for all the physical generators according to the first control parameters and the second control parameters.

6. The simulation method of the energy system simulation device according to claim 5, wherein, the individual operation test of each of the physical generators according to the input of the first control parameter includes: controlling the conversion contactor to turn off, and controlling the connection and disconnection of the load respectively through the grid connection contactors of each of the physical generators, so as to perform an individual operation test on each of the physical generators according to the first control parameter.

7. The simulation method of the energy system simulation device according to claim 5, wherein, the grid connection test of all the physical generators according to the first control parameter and the second control parameter includes: controlling the conversion contactor to turn on, and controlling the connection and disconnection of the load through the grid connection contactors of multiple physical generators, so as to perform a grid connection test on multiple physical generators according to the first control parameter and the second control parameter.

8. An energy system simulation system, wherein, it includes: including a host computer, a lower computer emulator, an access device with an I / O module, a physical circuit and a digital oscillograph connected in sequence; the host computer is used to construct an energy system simulation device and send the energy system simulation device to the lower computer emulator. The energy system simulation device includes: two generator control loops, and each generator control loop includes: a generator model and a controller model connected to the generator. In each generator control loop, the output current of the generator model is compared with the output voltage reference value after passing through a droop regulation module and fed back to the controller model; the lower computer emulator runs the energy system simulation device to obtain the grid connection operation control parameters of the generator model and feeds the grid connection operation control parameters back to the physical circuit. The physical circuit is the physical circuit of the energy system simulation device; the physical circuit includes: a physical controller and multiple physical generators connected to the physical controller. The output end of each physical generator is connected to multiple loads of different sizes through grid connection contactors, and the loads of the multiple physical generators are connected in parallel through a conversion contactor; the physical circuit performs tests according to the grid connection operation control parameters of the generator model and feeds the operation results back to the host computer, and the host computer displays them through the digital oscillograph.

9. The energy system simulation system according to claim 8, wherein, during the process of the lower computer emulator running the energy system simulation device, each of the generator models is individually debugged to obtain the first control parameter of the controller model connected to each of the generator models. After that, the grid connection algorithm of all the generator models is verified to obtain the second control parameter of the droop regulation module.

10. The energy system simulation system according to claim 9, wherein, The controller model implements individual operation tests for each of the physical generators according to the first control parameter input, or the controller model implements grid connection tests for all the physical generators according to the first control parameter and the second control parameter.

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