Operation control method, system and equipment of energy storage converter and storage medium

Abstract

The invention discloses an operation control method, system and device of an energy storage converter and a storage medium, which are applied to the technical field of power grids, and the method comprises the following steps: establishing a circuit model of a single energy storage converter; based on the circuit model, establishing a small signal model based on the virtual direct current motor; multiplying the direct-current bus voltage deviation by a compensation coefficient k, and then compensating the direct-current bus voltage deviation to armature voltage in the small-signal model to obtain a target model added with armature voltage compensation; and performing operation control of the energy storage converter based on the target model. By applying the scheme of the invention, the fluctuation of the bus voltage can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and particularly to an operation control method, system, device and storage medium for an energy storage converter. Background Art

[0002] With the vigorous development of new energy, DC microgrids have received extensive attention due to their advantages such as simple structure, easy acceptance of distributed renewable energy, and flexible working mode. In a DC microgrid, an energy storage converter based on a DC / DC converter is an important device for realizing energy flow and maintaining the stability of the bus voltage. However, fluctuations in loads and distributed power sources may cause severe fluctuations in the bus voltage, and even lead to stability problems, threatening the safe and stable operation of the DC microgrid. At the same time, the DC microgrid system lacks inertia and damping. When load disturbances, especially impact load disturbances, occur, the DC bus voltage rises or drops suddenly, which is not conducive to the stability of the DC microgrid system. Therefore, in a DC microgrid, it is necessary to suppress the fluctuations of the DC bus voltage and improve the quality of the bus voltage.

[0003] The methods for maintaining the stability of the bus voltage in a DC microgrid system are mainly divided into virtual capacitance control and VDCM (Virtual DC Machine) control. The latter can introduce the inertia characteristics and damping characteristics of a DC motor into the energy storage converter at the same time, thereby providing additional inertia and damping for the DC microgrid, having clear physical significance, and having more development prospects, and improving the stability of the DC microgrid to a certain extent. At present, the research on the virtual DC motor control of the energy storage converter mainly focuses on simulating the operation mechanism of the DC motor, so that the energy storage converter exhibits the inertia and damping characteristics of the DC motor. However, with the development of the DC microgrid, the impact of the connected load on the bus voltage is increasing. Therefore, the current solutions still need to be optimized in reducing the fluctuations of the bus voltage.

[0004] In summary, how to effectively solve the operation control of the energy storage converter and reduce the fluctuations of the bus voltage is an urgent technical problem that needs to be solved by those skilled in the art at present. Summary of the Invention

[0005] The purpose of the present invention is to provide an operation control method for an energy storage converter to effectively solve the operation control of the energy storage converter and reduce the fluctuations of the bus voltage.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] An operation control method for an energy storage converter includes:

[0008] Establish a circuit model of a single energy storage converter;

[0009] Based on the circuit model, a small-signal model based on a virtual DC motor is established;

[0010] The DC bus voltage deviation is multiplied by a compensation coefficient k and then compensated to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation added;

[0011] Based on the target model, the operation control of the energy storage converter is performed.

[0012] In one embodiment, it further includes:

[0013] Based on the change of the current bus voltage, the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model are adjusted.

[0014] In one embodiment, based on the change of the current bus voltage, adjusting the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model includes:

[0015] When |Δu| < u lim , the compensation coefficient k is set to the initial compensation coefficient value k0, the moment of inertia J of the virtual DC motor in the target model is set to the initial moment of inertia value J0, and the damping coefficient D of the virtual DC motor in the target model is set to the initial damping coefficient value D0;

[0016] When |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, the moment of inertia J, the damping coefficient D, and the compensation coefficient k are gradually increased;

[0017] When |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, for the damping coefficient D, the damping coefficient D is gradually decreased, for the moment of inertia J, the moment of inertia J is first gradually decreased to J 0min , and then the moment of inertia J is gradually increased from J 0min to J0, for the compensation coefficient k, the compensation coefficient k is first gradually decreased to k 0min , and then the compensation coefficient k is gradually increased from k 0min to k0;

[0018] where Δu is the absolute value of the DC bus voltage deviation, u lim is a preset first threshold, J 0min is a preset minimum moment of inertia value and J 0min < J0, k 0min is a preset minimum compensation coefficient value and k 0min < k0.

[0019] In one embodiment, when |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, according to set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D;

[0020] When |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, according to set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D;

[0021] Wherein, h1, h2, and h3 are the preset moment of inertia amplification coefficient, the preset damping coefficient amplification coefficient, and the preset compensation coefficient amplification coefficient in sequence, a1 is the first parameter, b1 is the second parameter, and a1 = h1 / (Δu max - 2b1), Δu max is the maximum disturbance voltage, a3 is the third parameter, b3 is the fourth parameter, and a3 = h3 / (Δu max - 2b3),

[0022] In one embodiment, the established circuit model of a single energy storage converter includes: a first switch tube, a second switch tube, a first inductor, and a first capacitor;

[0023] The first end of the first inductor serves as the positive input terminal of the energy storage converter, the second end of the first inductor is respectively connected to the first end of the first switch tube and the first end of the second switch tube, the second end of the first switch tube serves as the negative input terminal of the energy storage converter, the second end of the second switch tube is connected to the first end of the first capacitor and the connection end serves as the positive output terminal of the energy storage converter, the second end of the first capacitor serves as the negative output terminal of the energy storage converter, and the second end of the first capacitor is connected to the second end of the first switch tube.

[0024] In one embodiment, the established small-signal model based on the virtual DC motor is expressed as:

[0025]

[0026] Wherein, L is the inductance value of the first inductor, C is the capacitance value of the first capacitor, R L is the internal resistance of the first inductor; d = 1 - D1, D1 is the steady-state duty ratio of the first switch tube, is the perturbation amount of the duty ratio of the first switch tube; U in , I in , Udc and I dc are, in sequence, the steady-state input voltage, steady-state input current, steady-state output voltage, and steady-state output current of the energy storage converter, and are, in sequence, the disturbance quantity of the input current, disturbance quantity of the input voltage, disturbance quantity of the output current, and disturbance quantity of the output voltage of the energy storage converter, where s is a differential operator.

[0027] In one implementation, the closed-loop transfer function G U (s) and the port output impedance G z (s) of the obtained target model are respectively expressed as:

[0028]

[0029]

[0030] where G PI1 (s) is the transfer function of the first PI controller for voltage control in the target model, G PI2 (s) is the transfer function of the second PI controller for current control in the target model, G m (s), G ud (s), G id (s), G1(s), G2(s), Z0(s), and G ii (s) are all intermediate variables, and V m is the carrier amplitude, ω0 is the rated mechanical angular velocity of the virtual DC motor, R a is the equivalent resistance of the armature circuit, C T is the torque coefficient, Φ is the magnetic flux, U ref is the target voltage of the DC bus, J is the moment of inertia of the virtual DC motor in the target model, and D is the damping coefficient of the virtual DC motor in the target model.

[0031] An operating control system for an energy storage converter includes:

[0032] A circuit model establishment module for establishing a circuit model of a single energy storage converter;

[0033] A small-signal model establishment module for establishing a small-signal model based on the virtual DC motor based on the circuit model;

[0034] An armature voltage compensation module for compensating the DC bus voltage deviation multiplied by a compensation coefficient k to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation added;

[0035] An operation control execution module for performing operation control of the energy storage converter based on the target model.

[0036] An operation control device for an energy storage converter, comprising:

[0037] A memory for storing computer programs;

[0038] A processor for executing the computer programs to implement the steps of the operation control method for the energy storage converter as described above.

[0039] A computer-readable storage medium having computer programs stored thereon, and when the computer programs are executed by a processor, the steps of the operation control method for the energy storage converter as described above are implemented.

[0040] Applying the technical solution provided by the embodiments of the present invention, after establishing the circuit model of a single energy storage converter, a small-signal model based on a virtual DC motor can be established based on the circuit model. Therefore, the solution of the present application can introduce the inertia characteristics and damping characteristics of the DC motor into the energy storage converter at the same time, which is beneficial to improving the stability of the DC microgrid. Furthermore, in order to effectively address the problem of bus voltage fluctuations caused by impact load disturbances, an armature voltage compensation loop is added on the basis of the virtual DC motor control in the solution of the present application, that is, the DC bus voltage deviation is multiplied by the compensation coefficient k and then compensated to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation added. Then, the operation control of the energy storage converter can be performed based on the target model.

[0041] In summary, since the solution of the present application adds an armature voltage compensation loop on the basis of the virtual DC motor control, the solution of the present application can effectively reduce the fluctuations of the bus voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0043] Figure 1 It is a flowchart of the implementation of an operation control method for an energy storage converter in the present invention;

[0044] Figure 2a It is a schematic diagram of the circuit model of a single energy storage converter established in a specific implementation manner;

[0045] Figure 2bIt is a block diagram of a control system after adding armature voltage compensation in a specific embodiment;

[0046] Figure 2c It is a schematic diagram of a small-signal model after adding armature voltage compensation in a specific embodiment;

[0047] Figure 3a It is a unit step response of the output impedance when the moment of inertia J changes in a specific embodiment;

[0048] Figure 3b It is a unit step response of the output impedance when the damping coefficient D changes in a specific embodiment;

[0049] Figure 3c It is a unit step response of the output impedance when the compensation coefficient k changes in a specific embodiment;

[0050] Figure 4a It is a schematic diagram of the change of the DC bus voltage U dc in a specific embodiment;

[0051] Figure 4b It is a schematic diagram of the value-taking method of the moment of inertia J corresponding to Figure 4a in a specific embodiment;

[0052] Figure 5a It is a dynamic response diagram of voltage and current when an impact load disturbance occurs under traditional virtual DC machine control;

[0053] Figure 5b It is a dynamic response diagram of voltage and current when an impact load disturbance occurs after adding armature voltage compensation in a specific embodiment;

[0054] Figure 5c It is a dynamic response diagram of voltage and current when an impact load disturbance occurs after adding armature voltage compensation and adopting a parameter adaptive method in a specific embodiment;

[0055] Figure 6 It is a schematic diagram of the structure of an operation control system of an energy storage converter in the present invention;

[0056] Figure 7 It is a schematic diagram of the structure of an operation control device of an energy storage converter in the present invention. Specific Embodiment

[0057] The core of the present invention is to provide an operation control method for an energy storage converter, which adds an armature voltage compensation loop on the basis of virtual DC machine control, so that the solution of the present application can effectively reduce the fluctuation of the bus voltage.

[0058] To enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0059] Please refer to Figure 1 , Figure 1 , which is the implementation flowchart of an operation control method for an energy storage converter in the present invention. The operation control method for the energy storage converter may include the following steps:

[0060] Step S101: Establish a circuit model of a single energy storage converter.

[0061] Specifically, first, a circuit model of a single energy storage converter can be established. Refer to Figure 2a , which is a schematic diagram of the circuit model of a single energy storage converter established in a specific implementation manner. Figure 2a The circuit model in

[0062] specifically includes: a first switch tube, a second switch tube, a first inductor, and a first capacitor.

[0063] Figure 2a In in , I in represents the steady-state input current of the energy storage converter, U dc represents the steady-state input voltage of the energy storage converter, U dc represents the steady-state output voltage of the energy storage converter, that is, the DC bus voltage, and I Figure 2a represents the steady-state output current of the energy storage converter. The first switch tube, the second switch tube, the first inductor, and the first capacitor are respectively marked as S1, S2, L, and C in Figure 2a . And a in a shows the model of an equivalent virtual DC motor of this circuit model, where E a is the armature voltage and R a is the equivalent resistance of the armature circuit.

[0064] Figure 2aIn the embodiments, a relatively general circuit model is shown. That is, for practical applications, different types of energy storage converters can usually be abstracted into this circuit model.

[0065] Step S102: Based on the circuit model, establish a small-signal model based on a virtual DC motor.

[0066] After obtaining this circuit model, mathematical modeling can be performed on the circuit model, that is, a small-signal model based on a virtual DC motor is established.

[0067] In a specific embodiment of the present invention, the established small-signal model based on a virtual DC motor can be specifically expressed as:

[0068]

[0069] where L is the inductance value of the first inductor, C is the capacitance value of the first capacitor, and R L is the internal resistance of the inductance of the first inductor; d = 1 - D1, D1 is the steady-state duty cycle of the first switch, is the perturbation of the duty cycle of the first switch; U in , I in , U dc and I dc are the steady-state input voltage, steady-state input current, steady-state output voltage, and steady-state output current of the energy storage converter in sequence, and are the perturbation of the input current, the perturbation of the input voltage, the perturbation of the output current, and the perturbation of the output voltage of the energy storage converter in sequence, and s is the differential operator.

[0070] Step S103: Multiply the DC bus voltage deviation by the compensation coefficient k and then compensate it to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation.

[0071] This application considers that when the impact load disturbance causes the bus voltage to fluctuate, compensation can be performed to reduce the bus voltage fluctuation. In the solution of this application, specifically, the DC bus voltage deviation △u is detected, and then the DC bus voltage deviation △u is multiplied by the compensation coefficient k and then compensated to the armature voltage E a in the small-signal model, so as to suppress the bus voltage fluctuation.

[0072] Specifically, when the load decreases, the DC bus voltage U dc will increase. At this time, the value of the DC bus voltage deviation △u will decrease. Multiply the DC bus voltage deviation △u by the compensation coefficient k and then compensate it to the armature voltage E a in the small-signal model, which will cause the armature voltage E a to decrease, and since the armature voltage Ea Subtracting the equivalent resistance R of the armature circuit a results in a voltage equal to the DC bus voltage U dc . Therefore, a decrease in the armature voltage E a will cause a decrease in the DC bus voltage U dc , that is, the suppression of the DC bus voltage deviation is achieved.

[0073] Similarly, when the load increases, the DC bus voltage U dc will drop. Through the compensation of the armature voltage in the solution of this application, it is beneficial to achieve the suppression of the DC bus voltage deviation. In this example, the DC bus voltage U dc can be restored.

[0074] After adding an armature voltage compensation link to the small-signal model obtained in step S102, the resulting model is called the target model, which can be referred to Figure 2b and Figure 2c . Figure 2b Figure [figure number] is a block diagram of the control system after adding armature voltage compensation in a specific embodiment, Figure 2c Figure [figure number] is a schematic diagram of the small-signal model after adding armature voltage compensation in a specific embodiment, that is, the schematic diagram of the target model described in step S103.

[0075] As can be seen from Figure 2b , the target model can be divided into three parts: the voltage control part, the virtual DC motor control part, and the current control part. For the voltage control part, Figure 2b the U in ref represents the target voltage of the DC bus. Subtracting the DC bus voltage U ref from U dc can obtain the DC bus voltage deviation △u. PI1 represents the PI controller used in the voltage control part, called the first PI controller. For the current control part, Figure 2b the I in ref represents the target current value of the energy storage converter, and i L is the actual current value of the energy storage converter, that is, the current value flowing through the first inductor L. PI2 represents the PI controller used in the current control part, called the second PI controller. The output of the voltage control part is the mechanical torque T m . Figure 2b the T in e in T is the electromagnetic torque, J is the moment of inertia, D is the damping coefficient, ω0 is the rated mechanical angular velocity of the virtual DC motor, ω is the actual angular velocity, C

[0076] In a specific embodiment of the present invention, the closed-loop transfer function G of the obtained target modelU (s) and port output impedance G z (s) are respectively expressed as:

[0077]

[0078]

[0079] wherein, G PI1 (s) is the transfer function of the first PI controller for voltage control in the target model, and G PI2 (s) is the transfer function of the second PI controller for current control in the target model, and G m (s), G ud (s), G id (s), G1(s), G2(s), Z0(s) and G ii (s) are all intermediate variables, and V m is the carrier amplitude, ω0 is the rated mechanical angular velocity of the virtual DC motor, and R a is the equivalent resistance of the armature circuit, C T is the torque coefficient, Φ is the magnetic flux, and U ref is the target voltage of the DC bus.

[0080] In Figure 2c the small-signal model with armature voltage compensation shown in the specific implementation manner, its closed-loop transfer function G U (s) and port output impedance G z (s) are expressed as above.

[0081] Step S104: Based on the target model, perform the operation control of the energy storage converter.

[0082] After obtaining the target model with armature voltage compensation, the operation control of the energy storage converter can be performed based on the target model, effectively ensuring the stability of the DC bus voltage.

[0083] In a specific implementation manner of the present invention, it may further include:

[0084] Based on the change of the current bus voltage, adjust the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model.

[0085] This implementation mode takes into account that the compensation coefficient k, the moment of inertia J, and the damping coefficient D can be preset as fixed values. This is a relatively simple implementation method, but it is difficult to obtain the most ideal dynamic regulation performance. In this regard, in this implementation mode, based on the change of the current bus voltage, the values of the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model can be adjusted. That is, the adaptive setting of the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D is realized, so as to obtain the ideal dynamic regulation performance.

[0086] When dynamically adjusting the compensation coefficient k, the moment of inertia J, and the damping coefficient D, there can be various specific implementation methods. However, it can be understood that the influence of the corresponding parameter changes on the output voltage and output current should be analyzed in advance, so as to dynamically adjust the compensation coefficient k, the moment of inertia J, and the damping coefficient D with the goal of obtaining more ideal dynamic regulation performance.

[0087] In a specific implementation mode of the present invention, based on the change of the current bus voltage, adjusting the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model may specifically include:

[0088] When |△u| < u lim , set the compensation coefficient k to the initial compensation coefficient value k0, set the moment of inertia J of the virtual DC motor in the target model to the initial moment of inertia value J0, and set the damping coefficient D of the virtual DC motor in the target model to the initial damping coefficient value D0;

[0089] When |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, gradually increase the moment of inertia J, the damping coefficient D, and the compensation coefficient k;

[0090] When |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, for the damping coefficient D, gradually decrease the damping coefficient D. For the moment of inertia J, first gradually decrease the moment of inertia J to J 0min , and then increase the moment of inertia J from J 0min gradually to J0. For the compensation coefficient k, first gradually decrease the compensation coefficient k to k 0min , and then increase the compensation coefficient k from k 0min gradually to k0;

[0091] Among them, △u is the absolute value of the DC bus voltage deviation, u lim is the preset first threshold, J 0min is the preset minimum moment of inertia value and J 0min <J0, k 0minis the preset minimum compensation coefficient value and k 0min < k0.

[0092] Based on the port output impedance G z (s), the unit step responses of the output voltage and output current when the parameters change can be plotted. This unit step response reflects the response of the DC bus voltage to the change in the output current when the load power of the DC microgrid system is disturbed.

[0093] Refer to Figure 3a , Figure 3b and Figure 3c , Figure 3a is the unit step response of the output impedance when the moment of inertia J changes. It can be seen that as the moment of inertia J increases, the voltage response slows down, and the voltage fluctuation amplitude becomes smaller, indicating that the system inertia increases and the ability to suppress voltage mutations is enhanced. However, the disadvantage is that the voltage overshoot increases and the dynamic time becomes longer. Therefore, when the absolute value of the DC bus voltage deviation is large, the moment of inertia J can be increased to suppress the DC bus voltage deviation.

[0094] Figure 3b is the unit step response of the output impedance when the damping coefficient D changes. It can be seen that within a certain range, as the damping coefficient D increases, the overshoot of the voltage significantly becomes smaller, and the time required to return to stability becomes shorter.

[0095] Figure 3c is the unit step response of the output impedance when the compensation coefficient k changes. As the compensation coefficient k increases, the amplitude of the DC bus voltage disturbance and the overshoot of the voltage can be more effectively reduced. However, the disadvantage is that the time required to return to stability will become longer.

[0096] Based on the above analysis, in this implementation, when |△u| < u lim , it indicates that the absolute value of the DC bus voltage deviation is small. Therefore, the compensation coefficient k can be set to the initial compensation coefficient value k0, the moment of inertia J of the virtual DC motor in the target model can be set to the initial moment of inertia value J0, and the damping coefficient D of the virtual DC motor in the target model can be set to the initial damping coefficient value D0. That is to say, at this time, the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D are all their respective initial values.

[0097] Refer to Figure 4a , which is a schematic diagram of the change of the DC bus voltage U dc in a specific implementation. Before the t0 moment of Figure 4a , since the DC bus voltage U dc is always equal to the target voltage U ref of the DC bus, △u is 0 at this time, and the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D are all their respective initial values.

[0098] Figure 4a DC bus voltage U after time t0 dc rapidly drops. When |Δu| ≥ u lim and the DC bus voltage deviation gradually increases, in this implementation, the moment of inertia J, damping coefficient D, and compensation coefficient k will gradually increase. This is because increasing the moment of inertia J at this time is beneficial for suppressing the DC bus voltage deviation, increasing the damping coefficient D is beneficial for reducing the overshoot of the voltage, and increasing the compensation coefficient k is also beneficial for reducing the amplitude of the DC bus voltage disturbance and the overshoot of the voltage.

[0099] Of course, when |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, there are various specific implementation methods for gradually increasing the moment of inertia J, damping coefficient D, and compensation coefficient k. For example, in one case, considering that it can be achieved through a linear function and is relatively simple and convenient to implement, in a specific implementation of the present invention, when |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, it can be specifically set according to the values of the compensation coefficient k, moment of inertia J, and damping coefficient D, so that in this case, the compensation coefficient k, moment of inertia J, and damping coefficient D will all gradually increase.

[0100] h1, h2, and h3 are the preset moment of inertia amplification factor, preset damping coefficient amplification factor, and preset compensation coefficient amplification factor respectively, all of which are positive numbers, and their specific values can be set and adjusted according to the actual situation. Similarly, the values of other related parameters involved, such as the first threshold u described above lim can be set and adjusted according to the actual situation.

[0101] Please refer to Figure 4b , which is a schematic diagram of the value-taking method of the moment of inertia J corresponding to the situation of Figure 4a in a specific implementation. Since in the Figure 4a stage from t0 to t1 of lim |Δu| ≥ u and the DC bus voltage deviation gradually increases, therefore, J = J0 + h1|Δu| can be set to gradually increase the value of the moment of inertia J. Similarly, in the Figure 4a stage from t2 to t3 of lim |Δu| ≥ u and the DC bus voltage deviation gradually increases, therefore, J = J0 + h1|Δu| can be set.

[0102] It can be understood that as the absolute value of the DC bus voltage deviation continuously increases and reaches the maximum, it will then decline, that is, at this time, the absolute value of the DC bus voltage deviation will gradually decrease. Still taking the moment of inertia J as an example, since when increasing the moment of inertia J, in one of the above embodiments, the value of the moment of inertia J is linearly increased in the manner of J = J0 + h1|△u|. Therefore, when the absolute value of the DC bus voltage deviation gradually decreases, a simple implementation is to also linearly decrease the value of the moment of inertia J in the manner of J = J0 + h1|△u|, so that the value of the moment of inertia J does not change abruptly.

[0103] However, this implementation further considers that when the absolute value of the DC bus voltage deviation gradually decreases, the value of the moment of inertia J can be quickly reduced first until it reaches the preset minimum moment of inertia value J 0min , it can be understood that J 0min should be lower than the initial moment of inertia value J0. Subsequently, as the absolute value of the DC bus voltage deviation continues to decrease, the value of the moment of inertia J is then increased from the minimum moment of inertia value J 0min to the initial moment of inertia value J0. This is beneficial in the first stage when the absolute value of the DC bus voltage deviation gradually decreases. By reducing the value of the moment of inertia J to J 0min , the voltage overshoot can be effectively reduced and the dynamic time can be decreased. And in the later stage when the absolute value of the DC bus voltage deviation gradually decreases, the value of the moment of inertia J is then gradually increased from the minimum moment of inertia value J 0min to the initial moment of inertia value J0.

[0104] In addition, the above description uses the moment of inertia J as an example. For the compensation coefficient k, the same implementation can also be adopted. Therefore, in this implementation, when |△u|≥u lim and the absolute value of the DC bus voltage deviation gradually decreases, for the moment of inertia J, first the moment of inertia J is gradually decreased to J 0min , and then the moment of inertia J is gradually increased from J 0min to J0. Similarly, for the compensation coefficient k, first the compensation coefficient k is gradually decreased to k 0min , and then the compensation coefficient k is gradually increased from k 0min to k0.

[0105] In practical applications, there are various functional forms that can achieve the above requirements for the value change of the moment of inertia J. For example, a quadratic function form can usually be adopted. Similarly, for the value of the compensation coefficient k, a quadratic function form can also be used to determine it. And it should be noted that whether it is the process of increasing the moment of inertia J or the process of decreasing the moment of inertia J, the moment of inertia J should not change abruptly, that is, throughout the whole process, it is necessary to ensure that the moment of inertia J does not mutate. InFigure 4b As can be seen from the example, the value of the moment of inertia J changes continuously and does not mutate. Similarly, throughout the whole process, it should also be ensured that the compensation coefficient k does not mutate and the damping coefficient D does not mutate.

[0106] In a specific embodiment of the present invention, when |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, it can be set according to the values of the compensation coefficient k and the moment of inertia J, that is, in this embodiment, in this case, the values of the moment of inertia J and the compensation coefficient k are determined in the form of a quadratic function.

[0107] h1 is a preset moment of inertia amplification coefficient, h3 is a preset compensation coefficient amplification coefficient, a1 is a first parameter, b1 is a second parameter, and a1 = h1 / (Δu max - 2b1), Δu max is the maximum disturbance voltage, that is, after the DC bus voltage deviation appears this time, the maximum deviation value. a3 is a third parameter, b3 is a fourth parameter, and a3 = h3 / (Δu max - 2b3),

[0108] Figure 4b This embodiment is adopted. In the embodiment of Figure 4, as the absolute value of the DC bus voltage deviation continuously increases and increases to the maximum value Δu max , and then the absolute value of the DC bus voltage deviation starts to decrease. When the absolute value of the DC bus voltage deviation |Δu| is equal to b1, the value of the moment of inertia J decreases to the minimum value J 0min , and subsequently, as the absolute value of the DC bus voltage deviation |Δu| continues to decrease, the value of the moment of inertia J gradually returns to the initial moment of inertia value J0. In Figure 4a the t1 to t2 stage and the t3 to t4 stage, since |Δu| ≥ u lim and the DC bus voltage deviation gradually decreases, therefore, J = a1(|Δu| - b1) 2 + J 0min can be set.

[0109] And, Figure 4b taking the moment of inertia J as an example, the same is true for the compensation coefficient k and will not be repeated here.

[0110] For the damping coefficient D, since as the damping coefficient D increases, the overshoot of the voltage significantly becomes smaller and the time required to return to stability becomes shorter. Therefore, when |Δu| ≥ u limWhen the absolute value of the DC bus voltage deviation gradually increases, the damping coefficient D can be gradually increased according to the description above. When |Δu| ≥ u lim When the absolute value of the DC bus voltage deviation gradually decreases, it is only necessary to gradually decrease the damping coefficient D.

[0111] Therefore, in a specific embodiment of the present invention, when |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, the value of the damping coefficient D can be set according to D = D0 + h2|Δu|, where h2 is a preset damping coefficient amplification factor.

[0112] See Figure 5a , Figure 5a is the voltage and current dynamic response diagram when a shock load disturbance occurs under traditional virtual DC machine control. At 3 s, the load power changes from 7.5 kW to 15 kW. It can be seen that when traditional virtual DC machine control is adopted, the peak value of the DC bus voltage fluctuation is about 12 V, and the dynamic response time is about 0.7 s. The voltage change rate and fluctuation of the DC bus are relatively large, which is not conducive to the stability of the DC bus voltage.

[0113] Figure 5b is the voltage and current dynamic response diagram when a shock load disturbance occurs in a specific embodiment of the present invention after adding armature voltage compensation. Similarly, at 3 s, the load power changes from 7.5 kW to 15 kW. It can be seen that the peak value of the DC bus voltage fluctuation is only 6 V, but the dynamic time is extended to 0.8 s. The voltage change rate and fluctuation of the DC bus are reduced, but a certain dynamic time is increased.

[0114] Figure 5c is the voltage and current dynamic response diagram when a shock load disturbance occurs in a specific embodiment of the present invention after adding armature voltage compensation and adopting the parameter adaptive method above. Similarly, at 3 s, the load power changes from 7.5 kW to 15 kW. It can be seen that the peak value of the DC bus voltage fluctuation is only 2.3 V, and at the same time, the dynamic time is shortened to 0.5 s. The voltage change rate and fluctuation of the DC bus are reduced, and the dynamic time is shortened.

[0115] After establishing the circuit model of a single energy storage converter using the technical solution provided by the embodiments of the present invention, a small-signal model based on a virtual DC motor can be established based on the circuit model. Therefore, the solution of the present application can introduce the inertia characteristics and damping characteristics of the DC motor into the energy storage converter at the same time, which is beneficial to improving the stability of the DC microgrid. Furthermore, in order to effectively address the problem of bus voltage fluctuations caused by impact load disturbances, the present application solution adds an armature voltage compensation loop on the basis of virtual DC motor control, that is, multiplies the DC bus voltage deviation by the compensation coefficient k and then compensates it to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation. After that, the operation control of the energy storage converter can be carried out based on the target model.

[0116] In summary, since the solution of the present application adds an armature voltage compensation loop on the basis of VDCM control, the solution of the present application can effectively reduce the fluctuations of the bus voltage.

[0117] Corresponding to the above method embodiment, the embodiments of the present invention also provide an operation control system for an energy storage converter, which can be mutually corresponding and referenced with the above text.

[0118] See Figure 6 As shown in the figure, it is a schematic structural diagram of an operation control system for an energy storage converter. The operation control system for the energy storage converter includes:

[0119] A circuit model establishment module 601, configured to establish a circuit model of a single energy storage converter;

[0120] A small-signal model establishment module 602, configured to establish a small-signal model based on a virtual DC motor based on the circuit model;

[0121] An armature voltage compensation module 603, configured to multiply the DC bus voltage deviation by the compensation coefficient k and then compensate it to the armature voltage in the small-signal model to obtain a target model with armature voltage compensation;

[0122] An operation control execution module 604, configured to perform operation control of the energy storage converter based on the target model.

[0123] In a specific embodiment of the present invention, it further includes a parameter adjustment module, configured to:

[0124] Based on the change of the current bus voltage, adjust the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model.

[0125] In a specific embodiment of the present invention, the parameter adjustment module specifically includes:

[0126] The first execution unit is used to: when |△u| < u lim set the compensation coefficient k to the initial compensation coefficient value k0, set the moment of inertia J of the virtual DC motor in the target model to the initial moment of inertia value J0, and set the damping coefficient D of the virtual DC motor in the target model to the initial damping coefficient value D0;

[0127] The second execution unit is used to: when |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, gradually increase the moment of inertia J, the damping coefficient D, and the compensation coefficient k;

[0128] The third execution unit is used to: when |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, for the damping coefficient D, gradually decrease the damping coefficient D, for the moment of inertia J, first gradually decrease the moment of inertia J to J 0min and then gradually increase the moment of inertia J from J 0min to J0, for the compensation coefficient k, first gradually decrease the compensation coefficient k to k 0min and then gradually increase the compensation coefficient k from k 0min to k0;

[0129] where, △u is the absolute value of the DC bus voltage deviation, u lim is a preset first threshold, J 0min is a preset minimum moment of inertia value and J 0min <J0, k 0min is a preset minimum compensation coefficient value and k 0min <k0.

[0130] In a specific embodiment of the present invention, when |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D according to ;

[0131] When |△u| ≥ u lim and the absolute value of the DC bus voltage deviation gradually decreases, set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D according to ;

[0132] where, h1, h2, and h3 are the preset moment of inertia amplification factor, the preset damping coefficient amplification factor, and the preset compensation coefficient amplification factor in sequence, a1 is the first parameter, b1 is the second parameter, and a1 = h1 / (△u max - 2b1), △u max is the maximum disturbance voltage, a3 is the third parameter, b3 is the fourth parameter, and a3 = h3 / (△umax -2b3)

[0133] In a specific embodiment of the present invention, the established circuit model of a single energy storage converter includes: a first switching tube, a second switching tube, a first inductor, and a first capacitor;

[0134] The first end of the first inductor serves as the positive input terminal of the energy storage converter. The second end of the first inductor is respectively connected to the first end of the first switching tube and the first end of the second switching tube. The second end of the first switching tube serves as the negative input terminal of the energy storage converter. The second end of the second switching tube is connected to the first end of the first capacitor, and the connection end serves as the positive output terminal of the energy storage converter. The second end of the first capacitor serves as the negative output terminal of the energy storage converter, and the second end of the first capacitor is connected to the second end of the first switching tube.

[0135] In a specific embodiment of the present invention, the established small-signal model based on a virtual DC motor is expressed as:

[0136]

[0137] where L is the inductance value of the first inductor, C is the capacitance value of the first capacitor, and R L is the internal resistance of the inductance of the first inductor; d = 1 - D1, where D1 is the steady-state duty cycle of the first switching tube, is the perturbation amount of the duty cycle of the first switching tube; U in , I in , U dc and I dc are respectively the steady-state input voltage, steady-state input current, steady-state output voltage, and steady-state output current of the energy storage converter, and are respectively the perturbation amount of the input current, perturbation amount of the input voltage, perturbation amount of the output current, and perturbation amount of the output voltage of the energy storage converter, and s is the differential operator.

[0138] In a specific embodiment of the present invention, the obtained closed-loop transfer function G U (s) and port output impedance G z (s) of the target model are respectively expressed as:

[0139]

[0140]

[0141] where G PI1 (s) is the transfer function of the first PI controller for voltage control in the target model, and G PI2(s) is the transfer function of the second PI controller for current control in the target model, G m (s), G ud (s), G id (s), G1(s), G2(s), Z0(s) and G ii (s) are all intermediate variables, and V m is the carrier amplitude, ω0 is the rated mechanical angular velocity of the virtual DC motor, R a is the equivalent resistance of the armature circuit, C T is the torque coefficient, Φ is the magnetic flux, U ref is the target voltage of the DC bus, J is the moment of inertia of the virtual DC motor in the target model, and D is the damping coefficient of the virtual DC motor in the target model.

[0142] Corresponding to the above method and system embodiments, an embodiment of the present invention further provides an operating control device for an energy storage converter and a computer-readable storage medium, which can be correspondingly referred to with the above text.

[0143] See Figure 7 As shown, it is a schematic structural diagram of an operating control device for an energy storage converter. The operating control device for the energy storage converter includes:

[0144] Memory 701: Used to store computer programs;

[0145] Processor 702: Used to execute computer programs to implement the steps of the operating control method of the energy storage converter in any of the above embodiments.

[0146] The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, it implements the steps of the operating control method of the energy storage converter in any of the above embodiments. The computer-readable storage medium mentioned here includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well-known in the technical field.

[0147] It should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0148] Those skilled in the art can further realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0149] Specific examples are used in this text to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for operating and controlling an energy storage converter, characterized in that, Including: Establishing a circuit model of a single energy storage converter; Based on the circuit model, establishing a small-signal model based on a virtual DC motor; Compensating the armature voltage in the small-signal model by multiplying the DC bus voltage deviation by a compensation coefficient k to obtain a target model with armature voltage compensation; Based on the target model, performing operation control of the energy storage converter.

2. The operating control method of the energy storage converter according to claim 1, characterized in that, Also including: Based on the change of the current bus voltage, adjusting the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model.

3. The operating control method of the energy storage converter according to claim 1, characterized in that Based on the change of the current bus voltage, adjusting the compensation coefficient k, the moment of inertia J of the virtual DC motor in the target model, and the damping coefficient D of the virtual DC motor in the target model, including: When |Δu| < u lim set the compensation coefficient k to the initial compensation coefficient value k0, set the moment of inertia J of the virtual DC motor in the target model to the initial moment of inertia value J0, and set the damping coefficient D of the virtual DC motor in the target model to the initial damping coefficient value D0; When |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, gradually increase the rotational inertia J, the damping coefficient D, and the compensation coefficient k; When |△u|≥u lim and the absolute value of the DC bus voltage deviation gradually decreases, for the damping coefficient D, gradually decrease the damping coefficient D, and for the moment of inertia J, first gradually decrease the moment of inertia J to J 0min , and then change the moment of inertia J from J 0min gradually increase to J0, for the compensation coefficient k, first gradually decrease the compensation coefficient k to k 0min , and then change the compensation coefficient k from k 0min gradually increase to k0; where △u is the absolute value of the DC bus voltage deviation, and u lim is a preset first threshold value, J 0min is a preset minimum moment of inertia value and J 0min <J0, k 0min is a preset minimum compensation coefficient value and k 0min <k0.

4. The operating control method of the energy storage converter according to claim 3, characterized in that, When |Δu| ≥ u lim and the absolute value of the DC bus voltage deviation gradually increases, according to set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D; When |△u|≥u lim and the absolute value of the DC bus voltage deviation gradually decreases, according to set the values of the compensation coefficient k, the moment of inertia J, and the damping coefficient D; Among them, h1, h2, and h3 are respectively the preset moment of inertia amplification factor, the preset damping coefficient amplification factor, and the preset compensation coefficient amplification factor. a1 is the first parameter, b1 is the second parameter, and a1 = h1 / (△u max - 2b1), △u max is the maximum disturbance voltage, a3 is the third parameter, b3 is the fourth parameter, and a3 = h3 / (△u max - 2b3), 5. The operation control method of the energy storage converter according to any one of claims 1 to 4, characterized in that, The established circuit model of a single energy storage converter includes: a first switching tube, a second switching tube, a first inductor, and a first capacitor; The first end of the first inductor serves as the positive input terminal of the energy storage converter, the second end of the first inductor is respectively connected to the first end of the first switching tube and the first end of the second switching tube, the second end of the first switching tube serves as the negative input terminal of the energy storage converter, the second end of the second switching tube is connected to the first end of the first capacitor and the connection end serves as the positive output terminal of the energy storage converter, the second end of the first capacitor serves as the negative output terminal of the energy storage converter, and the second end of the first capacitor is connected to the second end of the first switching tube.

6. The operating control method of the energy storage converter according to claim 5, wherein, The established small-signal model based on the virtual DC motor is expressed as: where, L is the inductance value of the first inductor, C is the capacitance value of the first capacitor, and R L is the internal resistance of the first inductor; d = 1 - D1, where D1 is the steady-state duty cycle of the first switching transistor, is the perturbation of the duty cycle of the first switching transistor; U in , I in , U dc and I dc are the steady-state input voltage, steady-state input current, steady-state output voltage, and steady-state output current of the energy storage converter, and are the perturbation of the input current, perturbation of the input voltage, perturbation of the output current, and perturbation of the output voltage of the energy storage converter, respectively, and s is the differential operator.

7. The operating control method of the energy storage converter according to claim 6, characterized in that, The closed-loop transfer function G U (s) and the port output impedance G z (s) are respectively expressed as: Among them, G PI1 (s) is the transfer function of the first PI controller for voltage control in the target model, G PI2 (s) is the transfer function of the second PI controller for current control in the target model, G m (s), G ud (s), G id (s), G1(s), G2(s), Z0(s) and G ii (s) are all intermediate variables, and V m is the carrier amplitude, ω0 is the rated mechanical angular velocity of the virtual DC motor, R a is the equivalent resistance of the armature circuit, C T is the torque coefficient, Φ is the magnetic flux, U ref is the target voltage of the DC bus, J is the moment of inertia of the virtual DC motor in the target model, and D is the damping coefficient of the virtual DC motor in the target model.

8. An operating control system for an energy storage converter, characterized in that, Including: A circuit model establishment module for establishing a circuit model of a single energy storage converter; A small-signal model establishment module for establishing a small-signal model based on a virtual DC motor based on the circuit model; An armature voltage compensation module for compensating the armature voltage in the small-signal model by multiplying the DC bus voltage deviation by a compensation coefficient k to obtain a target model with armature voltage compensation; An operation control execution module for performing operation control of the energy storage converter based on the target model.

9. An operating control device for an energy storage converter, characterized in that, Including: A memory for storing a computer program; A processor for executing the computer program to implement the steps of the operation control method of the energy storage converter according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by the processor, the steps of the operation control method of the energy storage converter according to any one of claims 1 to 7 are implemented.

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