New energy inertia damping simulation control system and method with supercapacitor energy storage

Abstract

The present invention discloses a new energy inertia damping simulation control system with supercapacitor energy storage, including a new energy power generation device, a DC bus and an inverter connected in sequence, and also includes a supercapacitor energy storage device connected to the DC bus. The supercapacitor energy storage device includes a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the inertia damping simulation control module includes a first adder, a first gainer, a second adder, a third adder, a first integrator, a second gainer, a fourth adder, a PI controller and a pulse width modulator connected in sequence; and also includes a second integrator and a third gainer. The inertia damping simulation control module outputs a pulse signal to control the on and off of the power switch device of the bidirectional DC / DC converter. The present invention uses a supercapacitor energy storage device to flexibly and accurately simulate the inertia damping response characteristics of a synchronous motor to achieve new energy friendly grid connection.

Description

Technical Field

[0001] The present invention relates to the field of smart grid control technology, and in particular to a new energy inertia damping simulation control system and method with supercapacitor energy storage. Background Art

[0002] At present, the development prospects of renewable energy such as photovoltaic and wind power are broader. At present, most new energy power generation is connected to the grid through power electronic inverters. Its power output is decoupled from the grid frequency and does not have the inertia and damping characteristics of synchronous generators. With the continuous increase in the penetration rate of new energy power generation, the frequency regulation ability of the power system has gradually decreased, resulting in a greater frequency change rate, frequency deviation and system oscillation under fault conditions, and in severe cases, it will even lead to machine cutting and power outage accidents.

[0003] To solve the above problems, the main solution is to use virtual synchronous generator (VSG) technology. One type of solution uses the synchronous motor rotor motion equation instead of the phase-locked loop to achieve grid synchronization, so that the inverter has the inertia and damping characteristics of the synchronous motor. However, this type of solution requires the inverter control structure to be redesigned, and it is difficult to transform the already put into operation renewable energy power generation equipment. Another type of solution introduces an additional loop in the traditional inverter control system to dynamically adjust the active link reference value according to the frequency change rate to simulate the inertia. The transformation is easy and easier to implement. However, on the one hand, due to the lack of simulation of the damping characteristics of the synchronous motor, the addition of the inertia control link will significantly weaken the stability of the system; on the other hand, the measurement noise of the frequency change rate may interfere with the stable control of the system. In addition, the energy source of the inertia simulation is currently mainly achieved through the load reduction operation of renewable energy or the extraction of the kinetic energy of the wind turbine rotor, which has a negative impact on the economy and stability of renewable energy power generation. Summary of the invention

[0004] The present invention provides a new energy inertia damping simulation control system and method with supercapacitor energy storage in order to solve the technical problems existing in the known technology.

[0005] The technical solution adopted by the present invention to solve the technical problems existing in the known technology is: a new energy inertia damping simulation control system with supercapacitor energy storage, comprising a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and outputs it to the AC power grid; it also includes a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor, the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device includes a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter, whose input end is connected to the positive and negative electrodes of the supercapacitor module, and whose output end is connected to the DC bus, comprises a power switch device; the inertia damping simulation control module comprises a first An adder, a first gain device, a second adder, a third adder, a first integrator, a second gain device, a fourth adder, a PI controller and a pulse width modulator; the first adder is an inverting adder, a positive input terminal of which inputs the square value of the actual voltage of the supercapacitor module, and a negative input terminal of which inputs the square value of the reference voltage of the supercapacitor module; the second adder is a non-inverting adder, one of the positive input terminals of which is connected to the output terminal of the first gain device, and the second positive input terminal of which inputs the rated frequency of the AC power grid; the third adder is an inverting adder, a positive input terminal of which is connected to the output terminal of the second adder, and the negative input terminal of which inputs the actual frequency of the AC power grid; the fourth adder is an inverting adder, a negative input terminal of which is connected to the output terminal of the second gain device, and a positive input terminal of which inputs the actual output power of the supercapacitor module; the PI controller outputs a duty cycle signal to the pulse width modulator, and the pulse width modulator outputs a pulse signal to control the on and off of the power switch device.

[0006] Furthermore, the inertia damping simulation control module also includes a second integrator and a third gain device; the third gain device has an input end connected to the output end of the third adder, and an output end connected to the input end of the second integrator; the output end of the second integrator is connected to the inverting input end of the first adder.

[0007] Furthermore, the gain value K3 of the third gain device is calculated according to the following formula:

[0008]

[0009] Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

[0010] Furthermore, the gain value K1 of the first gain device is calculated according to the following formula:

[0011]

[0012] In the formula, C SC represents the capacitance value of the supercapacitor module, f0 represents the rated frequency of the AC power grid, H v represents the simulated inertia time constant, and S0 represents the rated power of the inverter.

[0013] Furthermore, the gain value K2 of the second gain device is calculated according to the following formula:

[0014]

[0015] Where, X v Indicates the simulated reactance value.

[0016] Furthermore, the supercapacitor module includes a plurality of supercapacitor cells connected in series and parallel.

[0017] Furthermore, the inertia damping simulation control module also includes: a phase-locked loop for detecting real-time grid frequency, a supercapacitor module voltage acquisition unit for acquiring the actual voltage of the supercapacitor module, and a supercapacitor module power measurement unit for measuring the actual output power of the supercapacitor module.

[0018] Furthermore, the bidirectional DC-DC converter includes a first power switch device, a second power switch device and a filter inductor; the emitter of the first power switch device, the collector of the second power switch device and one end of the filter inductor are connected, the other end of the filter inductor is connected to the positive electrode of the supercapacitor module, the negative electrode of the supercapacitor module is connected to the emitter of the second power switch device, the positive electrode of the DC bus is connected to the collector of the first power switch device, and the negative electrode of the DC bus is connected to the emitter of the second power switch device.

[0019] The present invention also provides a new energy inertia damping simulation control method with supercapacitor energy storage, the method is provided with a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and outputs it to the AC power grid; a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor is also provided, the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device is provided with a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter, the input end of which is connected to the positive and negative electrodes of the supercapacitor module, and the output end of which is connected to the DC bus, and the inertia damping simulation control module is constructed using a power switch device; the inertia damping simulation control module is used to output a signal to control the operation of the power switch device;

[0020] Set the values ​​of simulated inertia time constant, simulated damping coefficient and simulated reactance; set the reference voltage of supercapacitor module; collect the actual voltage of supercapacitor module, the actual frequency of AC power grid and the actual output power of supercapacitor module; construct inertia damping simulation control module to realize the following functions:

[0021] The square difference between the actual voltage of the supercapacitor module and its reference voltage is multiplied by the gain coefficient K1, and then added to the rated frequency of the AC grid to obtain the simulated rotor frequency;

[0022] Among them, the gain coefficient K1 is calculated according to the following formula:

[0023]

[0024] Where: C SC represents the capacitance value of the supercapacitor module, f0 represents the rated grid frequency, H v represents the simulated inertia time constant, S0 represents the inverter rated power;

[0025] The difference between the simulated rotor frequency and the actual frequency of the AC power grid is integrated to obtain the simulated power angle, and then the simulated power angle is multiplied by the gain coefficient K2 to obtain the reference output power of the supercapacitor module;

[0026] The gain value K2 of the second gain device is calculated according to the following formula:

[0027]

[0028] The difference between the actual output power of the supercapacitor module and the reference output power of the supercapacitor module is processed by proportional integration to obtain a duty cycle signal, which is sent to the pulse width modulator, which generates a corresponding pulse signal to control the on and off of the power switch device.

[0029] Furthermore, the inertia damping simulation control module is enabled to realize the following functions:

[0030] The difference between the simulated rotor frequency at the current time node and the actual frequency of the AC power grid is multiplied by the gain coefficient K3, and then integrated to obtain the feedback signal Q; the square difference between the actual voltage of the supercapacitor module and its reference voltage is subtracted from the feedback signal Q, multiplied by the gain coefficient K1, and then added to the rated frequency of the AC power grid to obtain the simulated rotor frequency at the next time node;

[0031] The gain value K3 of the third gain device is calculated according to the following formula:

[0032]

[0033] Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, CSC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

[0034] The advantages and positive effects of the present invention are as follows: (1) The present invention enables the new energy power generation system to accurately and flexibly simulate the inertia and damping characteristics of the synchronous motor, realizes the friendly grid connection of new energy, improves the frequency regulation capability of the power grid, and ensures the safety of the new power system with low inertia and underdamping characteristics;

[0035] (2) The supercapacitor in the present invention is used as an energy storage element, which has the advantages of fast charging and discharging speed, high power density, and high number of cycles. The supercapacitor assembly is connected to the DC bus through a bidirectional DC / DC converter, without modifying the original topology of the new energy station, and has a wider voltage variation range, thereby improving energy utilization;

[0036] (3) The present invention establishes a coupling relationship between the supercapacitor voltage and the grid frequency. When the grid frequency returns to the rated frequency, the supercapacitor voltage can also be restored to the rated value without the need for additional charging measures, thereby ensuring the controllability of the supercapacitor voltage.

[0037] (4) The present invention uses the real-time frequency of the power grid to directly drive the control loop, without measuring the frequency change rate that is prone to cause noise and stability problems. At the same time, due to the reasonable configuration of the damping characteristics, the stability of the inertia response can still be better guaranteed when simulating a larger inertia time constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a structural block diagram of a new energy power generation inertia damping simulation control system with a supercapacitor energy storage device of the present invention;

[0039] Figure 2 is a topological diagram of a bidirectional DC / DC converter of the present invention;

[0040] Figure 3 It is a topological diagram of a supercapacitor module of the present invention;

[0041] Figure 4 It is a working principle diagram of an inertia damping simulation control module of the present invention.

[0042] Figure 2 Medium: u SC Indicates the actual voltage of the supercapacitor module, i SC Indicates the supercapacitor module discharge current, L SC represents the filter inductor, g1 represents the switching signal of the first power switch device, and g2 represents the switching signal of the second power switch device.

[0043] Figure 3 Middle: 1 represents a supercapacitor cell.

[0044] Figure 4 Medium: u SC Indicates the actual voltage of the supercapacitor module, u SC * Indicates the reference voltage of the supercapacitor module, C SC represents the capacitance value of the supercapacitor module, f0 represents the rated frequency of the AC power grid, H v represents the simulated inertia time constant, S0 represents the rated capacity of renewable energy generation, f g Indicates the actual frequency of the AC power grid, D v represents the simulated damping coefficient, 1 / s represents the integral operator, δ v Indicates the simulated power angle, X v represents the simulated reactance, P SC * Represents the reference output power of the supercapacitor module, P SC represents the actual output power of the supercapacitor module, and d represents the duty cycle of the first power switch device of the bidirectional DC / DC converter. DETAILED DESCRIPTION

[0045] In order to further understand the content, features and effects of the present invention, the following embodiments are listed and described in detail with reference to the accompanying drawings:

[0046] The Chinese meanings of the English terms involved in the present invention are: DC means direct current in Chinese, PI means proportional integral in Chinese, PLL means phase-locked loop in Chinese, and PWM means pulse width modulation in Chinese.

[0047] See also Figures 1 to 4A new energy inertia damping simulation control system with supercapacitor energy storage comprises a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and outputs it to the AC power grid; it also comprises a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor, the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device comprises a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter has an input end connected to the positive and negative electrodes of the supercapacitor module, and an output end connected to the DC bus, and comprises a power switch device; the inertia damping simulation control module comprises a first adder, a first gain device, a second adder connected in sequence The invention relates to a supercapacitor, a third adder, a first integrator, a second gain device, a fourth adder, a PI controller and a pulse width modulator; the first adder is an inverting adder, the positive phase input terminal of which inputs the square value of the actual voltage of the supercapacitor module, and the inverting input terminal of which inputs the square value of the reference voltage of the supercapacitor module; the second adder is a non-inverting adder, one of the positive phase input terminals of which is connected to the output terminal of the first gain device, and the second of the positive phase input terminals of which inputs the rated frequency of the AC power grid; the third adder is an inverting adder, the positive phase input terminal of which is connected to the output terminal of the second adder, and the actual frequency of the AC power grid is input to the inverting input terminal; the fourth adder is an inverting adder, the inverting input terminal of which is connected to the output terminal of the second gain device, and the actual output power of the supercapacitor module is input to the positive phase input terminal; the PI controller outputs a duty cycle signal to the pulse width modulator, and the pulse width modulator outputs a pulse signal to control the on and off of the power switch device.

[0048] Preferably, the inertia damping simulation control module may also include a second integrator and a third gain device; the third gain device has an input end connected to the output end of the third adder, and an output end connected to the input end of the second integrator; the output end of the second integrator is connected to another inverting input end of the first adder.

[0049] Preferably, the gain value K3 of the third gain device can be calculated according to the following formula:

[0050]

[0051] Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

[0052] Preferably, the gain value K1 of the first gain device can be calculated according to the following formula:

[0053]

[0054] In the formula, C SC represents the capacitance value of the supercapacitor module, f0 represents the rated frequency of the AC power grid, H v represents the simulated inertia time constant, and S0 represents the inverter rated power.

[0055] Preferably, the gain value K2 of the second gain device can be calculated according to the following formula:

[0056]

[0057] In the formula, X v Indicates the simulated reactance value.

[0058] Preferably, the supercapacitor module may include a plurality of supercapacitor cells 1 connected in series and in parallel.

[0059] Preferably, the inertia damping simulation control module may further include: a phase-locked loop for detecting real-time grid frequency, a supercapacitor module voltage acquisition unit for acquiring the actual voltage of the supercapacitor module, and a supercapacitor module power measurement unit for measuring the actual output power of the supercapacitor module.

[0060] Preferably, the bidirectional DC-DC converter may include a first power switch device, a second power switch device and a filter inductor; the emitter of the first power switch device, the collector of the second power switch device and one end of the filter inductor are connected, the other end of the filter inductor is connected to the positive electrode of the supercapacitor module, the negative electrode of the supercapacitor module is connected to the emitter of the second power switch device, the positive electrode of the DC bus is connected to the collector of the first power switch device, and the negative electrode of the DC bus is connected to the emitter of the second power switch device.

[0061] The present invention also provides an embodiment of a new energy inertia damping simulation control method with supercapacitor energy storage, wherein the method is provided with a new energy power generation device, a DC bus and an inverter connected in sequence, wherein the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and then outputs it to the AC power grid; a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor is also provided, and the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device is provided with a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter has an input end connected to the positive and negative electrodes of the supercapacitor module, and an output end connected to the DC bus, and is constructed using a power switch device; the inertia damping simulation control module is used to output a signal to control the operation of the power switch device;

[0062] Set the values ​​of simulated inertia time constant, simulated damping coefficient and simulated reactance; set the reference voltage of supercapacitor module; collect the actual voltage of supercapacitor module, the actual frequency of AC power grid and the actual output power of supercapacitor module; construct inertia damping simulation control module to realize the following functions:

[0063] The square difference between the actual voltage of the supercapacitor module and its reference voltage is multiplied by the gain coefficient K1, and then added to the rated frequency of the AC grid to obtain the simulated rotor frequency;

[0064] Among them, the gain coefficient K1 is calculated according to the following formula:

[0065]

[0066] Where: C SC represents the capacitance value of the supercapacitor module, f0 represents the rated grid frequency, H v represents the simulated inertia time constant, S0 represents the inverter rated power;

[0067] The difference between the simulated rotor frequency and the actual frequency of the AC power grid is integrated to obtain the simulated power angle, and then the simulated power angle is multiplied by the gain coefficient K2 to obtain the reference output power of the supercapacitor module;

[0068] The gain value K2 of the second gain device is calculated according to the following formula:

[0069]

[0070] The difference between the actual output power of the supercapacitor module and the reference output power of the supercapacitor module is processed by proportional integration to obtain a duty cycle signal, which is sent to the pulse width modulator, which generates a corresponding pulse signal to control the on and off of the power switch device.

[0071] Preferably, the inertia damping simulation control module can also realize the following functions:

[0072] The difference between the simulated rotor frequency at the current time node and the actual frequency of the AC power grid is multiplied by the gain coefficient K3, and then integrated to obtain the feedback signal Q; the square difference between the actual voltage of the supercapacitor module and its reference voltage is subtracted from the feedback signal Q, multiplied by the gain coefficient K1, and then added to the rated frequency of the AC power grid to obtain the simulated rotor frequency at the next time node;

[0073] The time difference between the current time node and the next time node is the program running cycle.

[0074] The gain value K3 of the third gain device can be calculated according to the following formula:

[0075]

[0076] Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

[0077] The above-mentioned first to fourth adders, first to third gain devices, first to second integrators, PI controller, pulse width modulator, bidirectional DC / DC converter, supercapacitor module, supercapacitor monomer, phase-locked loop, supercapacitor module voltage acquisition unit, supercapacitor module power measurement unit, first power switch device, second power switch device and filter inductor can all adopt applicable components or modules in the prior art; or adopt software and modules in the prior art and be constructed by conventional technical means.

[0078] The structure and working principle of the present invention are further described below with reference to a preferred embodiment of the present invention:

[0079] See also Figures 1 to 4 A new energy inertia damping simulation control system with supercapacitor energy storage comprises a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and outputs it to the AC power grid; it also comprises a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor, the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device comprises a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter has an input end connected to the positive and negative electrodes of the supercapacitor module, and an output end connected to the DC bus, and comprises a power switch device; the inertia damping simulation control module comprises a first adder, a first gain device, a second adder connected in sequence The invention relates to a supercapacitor, a third adder, a first integrator, a second gain device, a fourth adder, a PI controller and a pulse width modulator; the first adder is an inverting adder, the positive phase input terminal of which inputs the square value of the actual voltage of the supercapacitor module, and the inverting input terminal of which inputs the square value of the reference voltage of the supercapacitor module; the second adder is a non-inverting adder, one of the positive phase input terminals of which is connected to the output terminal of the first gain device, and the second of the positive phase input terminals of which inputs the rated frequency of the AC power grid; the third adder is an inverting adder, the positive phase input terminal of which is connected to the output terminal of the second adder, and the actual frequency of the AC power grid is input to the inverting input terminal; the fourth adder is an inverting adder, the inverting input terminal of which is connected to the output terminal of the second gain device, and the actual output power of the supercapacitor module is input to the positive phase input terminal; the PI controller outputs a duty cycle signal to the pulse width modulator, and the pulse width modulator outputs a pulse signal to control the on and off of the power switch device.

[0080] The input end of the PI controller is connected to the output end of the fourth adder, and the input end of the pulse width modulator is connected to the output end of the PI controller; the output end of the pulse width modulator is connected to the control signal end of the power switch device of the bidirectional DC-DC converter, and the pulse width modulator outputs a switching signal g1 for controlling the on and off of the first power switch device, and a switching signal g2 for controlling the on and off of the second power switch device.

[0081] The PI controller outputs a modulation ratio signal to the PWM pulse width modulator, and the PWM pulse width modulator outputs a matching pulse signal to control the conduction of the power switch device of the bidirectional DC-DC converter.

[0082] The first adder includes a positive input terminal and two negative input terminals; the positive input terminal inputs the square of the actual voltage of the supercapacitor module, and the negative input terminal inputs the square of the reference voltage of the supercapacitor module. The inertia damping analog control module also includes a second integrator and a third gain device; the third gain device has an input terminal connected to the output terminal of the third adder, and an output terminal connected to the input terminal of the second integrator; the output terminal of the second integrator is connected to another negative input terminal of the first adder.

[0083] The inverter includes a power switch device. The inverter uses an inverter control module to control the on and off of the power switch device of the inverter. The inverter control module controls the inverter to achieve energy and voltage conversion between the DC bus and the AC power grid.

[0084] The present invention also provides a preferred embodiment of a new energy power generation inertia damping simulation control method with a supercapacitor energy storage device, which is provided with a new energy power generation device, a DC bus and an inverter connected in sequence, wherein the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and outputs it to the AC power grid; a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of a synchronous motor is also provided, and the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device is provided with a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter has an input end connected to the positive and negative electrodes of the supercapacitor module, and an output end connected to the DC bus, and is constructed using a power switch device; an inertia damping simulation control module is constructed to realize the following functions:

[0085] The actual voltage u of the supercapacitor module SC With its reference voltage u SC * The square difference is multiplied by the gain coefficient K1, and then added to the rated frequency f0 of the AC power grid to obtain the simulated rotor frequency f of the simulated generator rotor. v .

[0086] Among them, the gain coefficient K1 is calculated according to the following formula:

[0087]

[0088] Where: C SC represents the capacitance value of the supercapacitor module, f0 represents the rated grid frequency, H v represents the simulated inertia time constant, S0 represents the inverter rated power;

[0089] The simulated rotor frequency f v The actual frequency of the AC power grid is f g The difference is integrated to obtain the simulated power angle δ v , and then the simulated power angle δ v Multiply by the gain coefficient K2 to get the reference output power P of the supercapacitor module SC * .

[0090] The actual output power P of the supercapacitor module SC With reference output power P SC * The difference is processed proportionally and integrally, and then the duty cycle signal is output to the pulse width modulator, which generates a pulse signal to control the on and off of the power switch device.

[0091] The inertia damping simulation control module can be constructed as follows to achieve the above functions:

[0092] A first adder, a first gain device, a second adder, a third adder, a first integrator, a second gain device, a fourth adder, a PI controller and a pulse width modulator are provided, which are connected in sequence; the first adder adopts an inverting adder, whose positive input terminal inputs the square value of the actual voltage of the supercapacitor module, and whose inverting input terminal inputs the square value of the reference voltage of the capacitor module; the second adder adopts a non-phase adder, whose one positive input terminal is connected to the output terminal of the first gain device, and whose second positive input terminal inputs the rated frequency of the AC power grid; the third adder adopts an inverting adder, whose positive input terminal is connected to the output terminal of the second adder, and whose inverting input terminal inputs the actual frequency of the AC power grid; the fourth adder adopts an inverting adder, whose inverting input terminal is connected to the output terminal of the second gain device, and whose positive input terminal inputs the actual output power of the supercapacitor module; the PI controller outputs a duty cycle signal to the pulse width modulator, and the pulse width modulator outputs a pulse signal to control the on and off of the power switch device.

[0093] The inertia damping simulation control module also realizes the following functions:

[0094] Set the current time node t n The simulated rotor frequency f v The actual frequency of the AC power grid is fg The difference is multiplied by the gain coefficient K3, and then integrated to obtain the feedback signal Q; the square difference between the actual voltage of the supercapacitor module and its reference voltage is subtracted from the feedback signal Q, multiplied by the gain coefficient K1, and then added to the rated frequency of the AC power grid to obtain the next time node t n+1 The simulated rotor frequency. n+1 -t n =Program operation cycle.

[0095] The gain value K3 of the third gain device is calculated according to the following formula:

[0096]

[0097] Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

[0098] The inertia damping simulation control module can be constructed as follows to achieve the above functions:

[0099] The inertia damping simulation control module is also provided with a second integrator and a third gainer; the third gainer has its input end connected to the output end of the third adder, and its output end connected to the input end of the second integrator; the output end of the second integrator is connected to the inverting input end of the first adder.

[0100] The specific derivation process of obtaining the reference output power of the supercapacitor module in the inertia damping simulation control module is as follows:

[0101] When the power grid is disturbed, the power change of the synchronous motor can be obtained from the rotor motion equation of the synchronous motor:

[0102]

[0103] Where: ΔP g represents the power change of the synchronous motor, H represents the inertia time constant of the synchronous motor; D represents the damping coefficient of the synchronous motor, f g represents the real-time grid frequency, and f represents the synchronous motor rotor frequency.

[0104] The power change during the charging process of the supercapacitor module is:

[0105]

[0106] Where: ΔP SC Indicates the electromagnetic power absorbed by the supercapacitor module, C SC Indicates the capacitance value of the supercapacitor module, u SCIndicates the actual voltage of the supercapacitor module, and S0 indicates the rated power of the inverter.

[0107] When using a supercapacitor module to simulate the inertia and damping of a synchronous motor:

[0108] ΔP g =ΔP SC ;

[0109]

[0110] Where: H v represents the simulated inertia time constant, D v represents the simulated damping coefficient, f v Indicates the simulated rotor frequency.

[0111] Integrate both sides of the above formula and sort them out:

[0112]

[0113] Where: 1 / s represents the integral operator, u SC * Represents the reference voltage of the supercapacitor module. The above formula can be used to construct a simulated rotor frequency for the supercapacitor module.

[0114] In order to achieve synchronization between the supercapacitor module and the power grid, the simulated rotor frequency f v and real-time grid frequency f g Subtracting and integrating, we get:

[0115]

[0116] Where: v Indicates the simulated power angle.

[0117] Combining the synchronous motor power transmission equation, we can get:

[0118]

[0119] Where: P SC * is the output power reference value of the supercapacitor module; E v and U are the simulated internal potential of the supercapacitor module and the grid voltage, respectively, which are approximately equal to 1; X v is the simulated reactance; due to δ v is also small, so it can be considered that sinδ v ≈δ v .

[0120] From the above formula, the output power reference value of the supercapacitor module can be obtained.

[0121] The connections mentioned above are electrical connections.

[0122] The embodiments described above are only used to illustrate the technical ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The patent scope of the present invention cannot be limited only by this embodiment, that is, any equivalent changes or modifications made to the spirit disclosed by the present invention still fall within the patent scope of the present invention.

Claims

1. A new energy inertia damping simulation control system with supercapacitor energy storage, comprising a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and then outputs it to the AC power grid; characterized in that: The invention also includes a supercapacitor energy storage device for absorbing or releasing electric energy to simulate the inertia damping power response of the synchronous motor, wherein the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device includes a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; a bidirectional DC / DC converter, whose input end is connected to the positive and negative electrodes of the supercapacitor module and whose output end is connected to the DC bus, includes a power switch device; an inertia damping simulation control module, which includes a first adder, a first gain device, a second adder, a third adder, a first integrator, a second gain device, a fourth adder, a PI controller and a pulse width modulator connected in sequence; the first adder is an inverting adder, whose positive The square value of the actual voltage of the supercapacitor module is input to the phase input end, and the square value of the reference voltage of the supercapacitor module is input to the inverting input end; the second adder is a common-phase adder, one of the positive-phase input ends of which is connected to the output end of the first gain device, and the rated frequency of the AC power grid is input to the second positive-phase input end; the third adder is an inverting adder, the positive-phase input end of which is connected to the output end of the second adder, and the actual frequency of the AC power grid is input to the inverting input end; the fourth adder is an inverting adder, the inverting input end of which is connected to the output end of the second gain device, and the actual output power of the supercapacitor module is input to the positive-phase input end; the PI controller outputs a duty cycle signal to the pulse width modulator, and the pulse width modulator outputs a pulse signal to control the on and off of the power switch device; The inertia damping simulation control module also includes a second integrator and a third gain device; the third gain device has an input end connected to the output end of the third adder, and an output end connected to the input end of the second integrator; the output end of the second integrator is connected to the inverting input end of the first adder.

2. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The gain value K3 of the third gain device is calculated according to the following formula: Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

3. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The gain value K1 of the first gain amplifier is calculated according to the following formula: In the formula, C SC represents the capacitance value of the supercapacitor module, f0 represents the rated frequency of the AC power grid, H v represents the simulated inertia time constant, and S0 represents the inverter rated power.

4. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The gain value K2 of the second gain device is calculated according to the following formula: Where, X v Indicates the simulated reactance value.

5. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The supercapacitor module includes a plurality of supercapacitor cells connected in series and parallel.

6. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The inertia damping analog control module also includes: a phase-locked loop for detecting the real-time grid frequency, a supercapacitor module voltage acquisition unit for acquiring the actual voltage of the supercapacitor module, and a supercapacitor module power measurement unit for measuring the actual output power of the supercapacitor module.

7. The new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1 is characterized in that: The bidirectional DC-DC converter includes a first power switch device, a second power switch device and a filter inductor; the emitter of the first power switch device, the collector of the second power switch device and one end of the filter inductor are connected, the other end of the filter inductor is connected to the positive electrode of the supercapacitor module, the negative electrode of the supercapacitor module is connected to the emitter of the second power switch device, the positive electrode of the DC bus is connected to the collector of the first power switch device, and the negative electrode of the DC bus is connected to the emitter of the second power switch device.

8. A new energy inertia damping simulation control method with supercapacitor energy storage using the new energy inertia damping simulation control system with supercapacitor energy storage according to claim 1, the method is provided with a new energy power generation device, a DC bus and an inverter connected in sequence, the new energy power generation device outputs DC power to the DC bus, the inverter maintains a constant voltage of the DC bus, and converts the DC power of the DC bus into AC power and then outputs it to the AC power grid; characterized in that, A supercapacitor energy storage device is also provided for absorbing or releasing electric energy to simulate the inertia damping power response of the synchronous motor, and the supercapacitor energy storage device is connected to the DC bus; the supercapacitor energy storage device is provided with a supercapacitor module, a bidirectional DC / DC converter and an inertia damping simulation control module connected in sequence; the bidirectional DC / DC converter has an input end connected to the positive and negative electrodes of the supercapacitor module, and an output end connected to the DC bus, and is constructed using a power switch device; the inertia damping simulation control module is used to output a signal to control the operation of the power switch device; Set the values ​​of simulated inertia time constant, simulated damping coefficient and simulated reactance; set the reference voltage of supercapacitor module; collect the actual voltage of supercapacitor module, the actual frequency of AC power grid and the actual output power of supercapacitor module; construct inertia damping simulation control module to realize the following functions: The square difference between the actual voltage of the supercapacitor module and its reference voltage is multiplied by the gain coefficient K1, and then added to the rated frequency of the AC grid to obtain the simulated rotor frequency; Among them, the gain coefficient K1 is calculated according to the following formula: Where: C SC represents the capacitance value of the supercapacitor module, f0 represents the rated grid frequency, H v represents the simulated inertia time constant, S0 represents the inverter rated power; The difference between the simulated rotor frequency and the actual frequency of the AC power grid is integrated to obtain the simulated power angle, and then the simulated power angle is multiplied by the gain coefficient K2 to obtain the reference output power of the supercapacitor module; The gain value K2 of the second gain device is calculated according to the following formula: Where, X v Indicates the simulated reactance value; The difference between the actual output power of the supercapacitor module and the reference output power of the supercapacitor module is processed by proportional integration to obtain a duty cycle signal, which is sent to the pulse width modulator, which generates a corresponding pulse signal to control the on and off of the power switch device.

9. The new energy inertia damping simulation control method with supercapacitor energy storage according to claim 8 is characterized in that: The inertia damping simulation control module also realizes the following functions: The difference between the simulated rotor frequency at the current time node and the actual frequency of the AC power grid is multiplied by the gain coefficient K3, and then integrated to obtain the feedback signal Q; the square difference between the actual voltage of the supercapacitor module and its reference voltage is subtracted from the feedback signal Q, multiplied by the gain coefficient K1, and then added to the rated frequency of the AC power grid to obtain the simulated rotor frequency at the next time node; The gain value K3 of the third gain device is calculated according to the following formula: Where D v represents the simulated damping coefficient, S0 represents the inverter rated power, C SC It represents the capacitance value of the supercapacitor module, and f0 represents the rated frequency of the AC power grid.

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