A voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control

Abstract

The application discloses a kind of based on quasi-resonance control's bidirectional interleaved converter voltage regulation method, belong to new energy electric energy conversion technical field.It includes the following steps: the state space equation of bidirectional interleaved converter is constructed;For bidirectional interleaved converter, the double closed loop control structure based on voltage outer ring and current inner ring is designed;Estimate the system internal and external total disturbance of linear active disturbance rejection control;Obtain the active disturbance rejection control proportional controller;Realize the design process of bidirectional interleaved converter voltage regulation method based on quasi-resonance control.The application provides a kind of based on quasi-resonance control's bidirectional interleaved converter voltage regulation method, solves the problem that active disturbance rejection controller faces periodic disturbance suppression ability is weak.The application can be applied to various DC converters, thereby improving the working performance of the controlled object under periodic disturbance.The application is simple and practical, and has wide versatility.

Description

Technical Field

[0001] This invention relates to the field of new energy power conversion technology, and in particular to a voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control. Background Technology

[0002] In recent years, with the increasing severity of the energy crisis, green and pollution-free new energy power generation technologies, represented by wind, solar, hydropower, and hydrogen energy, have received widespread attention. New energy hybrid power supply systems that intelligently control and apply these energy sources have also developed rapidly. In hybrid power supply systems, lithium batteries play a crucial role due to their significant advantages such as light weight, high energy density, low self-discharge rate, and long lifespan. Bidirectional DC-DC converters can be applied to energy flow, voltage control, power distribution, and battery state estimation in lithium batteries. However, in practical applications, DC-DC converters often face various external factors, causing strong periodic fluctuations in their load current and voltage, posing a severe challenge to the stable optimization and control of the converter. Therefore, to improve the overall performance of the new energy system, a voltage regulation method based on a bidirectional interleaved converter needs to be designed, considering the periodic disturbances at the converter load end.

[0003] Over the past few decades, automatic control theory has seen the emergence of a series of advanced nonlinear control methods, such as classical proportional-integral-derivative (PID) control, sliding mode control, adaptive control, model predictive control, robust control, and neural network control. Among these, Active Disturbance Rejection (ADRF) technology was proposed by Professor Han Jingqing in 1998. Its development embodies Professor Han's unique insights into linearity and nonlinearity in feedback systems, and whether control theory is model theory or control theory. It attributes all uncertainties acting on the controlled object to "unknown disturbances," estimating and compensating for them using the object's input-output data, thus overcoming the limitations of the "absolute invariance principle" and the "internal model principle." Later, Professor Gao Zhiqiang modified the ADRF controller into a linear form, reducing its controller parameters to two, further expanding the theory's application and development. Currently, after more than two decades of engineering, especially linearization and parameterization, ADRF technology has matured technically and its application scope has expanded continuously. It is a new type of practical control technology that adapts to the trend of digital control, absorbs the achievements of modern control theory, promotes and enriches the essence of PID, and develops and utilizes special nonlinear effects.

[0004] Theoretical and experimental results show that the control performance of an active disturbance rejection controller (ADRC) largely depends on the performance of its observer. ADRC is essentially a linear controller, and its extended state observer has limited bandwidth. There is a certain steady-state error between the estimated periodic disturbance and the actual disturbance, making it difficult for ADRC to effectively suppress periodic disturbances. Summary of the Invention

[0005] The purpose of this invention is to provide a bidirectional interleaved converter voltage regulation method based on quasi-resonant control, which solves the problem of the limitations of linear active disturbance rejection controllers in controlling periodic disturbances at the load end in DC converters.

[0006] To achieve the above objectives, this invention provides a voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control, comprising the following steps:

[0007] S1. Construct the state-space equations of the bidirectional interleaved converter;

[0008] S2. A dual closed-loop control structure based on an outer voltage loop and an inner current loop is designed for the bidirectional interleaved converter. First, the inner current loop adopts the super-twisting sliding mode control algorithm, and the power relationship of the inner current loop of the converter is given.

[0009] S3. Based on the current inner loop power relationship obtained in step S2, use the linear active disturbance rejection control theory to design an extended state observer to estimate the total internal and external disturbances of the linear active disturbance rejection control system.

[0010] S4. For the total internal and external disturbances of the linear active disturbance rejection control system obtained in step S3, design a proportional controller to control the unity-gain first-order system based on the pre-selected control bandwidth.

[0011] S5. For the active disturbance rejection control proportional controller obtained in step S4, by adding the transfer function of the quasi-resonant controller, an improved active disturbance rejection control proportional controller based on quasi-resonant control is obtained, completing the design process of the extended state observer based on the improved quasi-resonant control and performing voltage regulation, thereby realizing the design process of the entire bidirectional interleaved converter voltage regulation method based on quasi-resonant control.

[0012] Preferably, in step S1, its state-space equation is:

[0013]

[0014] Where L1 and L2 are the two input inductance values ​​of the converter; r L1 r L2 These are the parasitic resistances of the two input inductors; C is the output capacitance of the converter; i L1 i L2 It is the current value flowing through the two inductors; v o d1 and d2 are the output voltage of the converter; d1 and d2 are the duty cycles of the two switches of the converter.

[0015] Preferably, in step S2, the power relationship of the inner current loop is as follows:

[0016]

[0017] Among them, W E It is the energy stored in the capacitor, P DG It is the converter input power, P Loss It is the converter power loss, P o This is the converter's rated load power, including line loss P. Line and load power P R Two parts.

[0018] Preferably, in step S3, the total internal and external disturbances of the linear active disturbance rejection control system are designed as follows:

[0019]

[0020] Where y = W E ,u=I Lref f0 represents the total disturbance of the converter system.

[0021] Preferably, in step S4, the proportional controller is as follows:

[0022] u0 = k p (E ref -y)

[0023] Where, k p E is the gain of the proportional controller. ref This is a reference value for output power.

[0024] Preferably, in step S5, the active disturbance rejection control proportional controller based on the quasi-resonant control improvement is as follows:

[0025]

[0026] Among them, G c It is the transfer function of the quasi-resonant controller.

[0027] Therefore, the present invention provides a bidirectional interleaved converter voltage regulation method based on quasi-resonant control with the above-described structure, which has the following beneficial effects:

[0028] This invention embeds a quasi-resonant controller into the proportional control loop of the observer, enhancing the suppression of periodic disturbances through feedback, thereby improving the control performance of the converter's outer voltage loop. This invention can be applied to a wide variety of DC-DC converters, thereby improving the performance of the controlled object under periodic disturbances. Compared to linear active disturbance rejection control methods, this invention can significantly suppress periodic disturbances at the load end of the DC-DC converter.

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0030] Figure 1 This is a topology diagram of a bidirectional interleaved converter based on a quasi-resonant control voltage regulation method according to the present invention.

[0031] Figure 2 This is a flowchart of a bidirectional interleaved converter voltage regulation method based on quasi-resonant control, according to the present invention.

[0032] Figure 3 This is a block diagram of the active disturbance rejection control of a bidirectional interleaved converter voltage regulation method based on quasi-resonant control, according to the present invention.

[0033] Figure 4 This refers to the output voltage of the bidirectional interleaved converter of the present invention when a periodic sinusoidal disturbance occurs on the load side;

[0034] Figure 5 This invention relates to a method for regulating the voltage of a bidirectional interleaved converter based on quasi-resonant control, which describes the output voltage of the bidirectional interleaved converter when a periodic sinusoidal disturbance occurs on the load side. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0037] Example

[0038] This embodiment uses a bidirectional interleaved converter experiencing a periodic sinusoidal disturbance on the load side as an example. Before 1 second, the bidirectional interleaved converter operates normally, and its topology is as follows: Figure 1 As shown, a periodic sinusoidal disturbance appears on the load side at 1 second. The flowchart of this invention is as follows. Figure 2 As shown.

[0039] like Figure 1-5 As shown, this invention provides a voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control, comprising the following steps:

[0040] S1. Construct the state-space equations of the bidirectional interleaved converter, from which... Figure 1 It can be seen that the bidirectional interleaved Boost converter can be considered as a combination of two standard Boost circuits connected in parallel at the input and in parallel at the output. Based on the converter's operating state in continuous conduction mode, its state-space equation can be obtained:

[0041]

[0042] Where L1 and L2 are the two input inductance values ​​of the converter; r L1 r L2 These are the parasitic resistances of the two input inductors; C is the output capacitance of the converter; i L1 i L2 It is the current value flowing through the two inductors; V o d1 and d2 are the output voltage of the converter; d1 and d2 are the duty cycles of the two switches of the converter.

[0043] Table 1 shows the simulation parameters for normal operation of the bidirectional interleaved converter:

[0044] Inductance (L) 800μH <![CDATA[Inductive resistance (r L )]]> 0.2Ω Capacitor (C) 220μF <![CDATA[Capacitor Resistor (r c )]]> 20mΩ <![CDATA[Input voltage (V in )]]> 5V <![CDATA[Output voltage (V o )]]> 48V

[0045] S2. For the inner current loop, the super-twisting sliding mode control algorithm is adopted, and its control law can be defined as:

[0046]

[0047] Among them, s k is the sliding surface, sgn is the sign function, and λ and α are the controller parameters to be designed.

[0048] Based on the invariable condition The equivalent duty cycle d can be calculated. eq :

[0049]

[0050] Substituting equation (3) into equation (1), we can obtain the following relationship for the power of the inner current loop:

[0051]

[0052] Among them, W E It is the energy stored in the capacitor, P DG It is the converter input power, P Loss It is the converter power loss, Po This is the converter's rated load power, including line loss P. Line and load power P R Two parts.

[0053] Due to the converter input power P DG It should be related to the converter power loss P Loss The rated load power P of the converter o The two conditions are matched, but the latter is constantly changing. Therefore, a voltage outer loop control method based on an active disturbance rejection control extended state observer is proposed. The uncertain P... Loss P o As a total disturbance, it is considered an extended state. An extended state observer can estimate the system state and the augmented state in real time, and then eliminate them in the control law;

[0054] S3. Define the state variable y = W E The control variable is u = I Lref f0=(b-b0)uP Loss -P o Let represent the total disturbance of the converter system. Then, the design of the total internal and external disturbances of the linear active disturbance rejection control in step three is as follows:

[0055]

[0056] Define the state variable x = [x1, x2] T =[y,f] T Then equation (4) can be rewritten as:

[0057]

[0058] in C = [1 0];

[0059] In order to achieve active disturbance rejection control, a second-order linear extended state observer is designed according to equation (5) to observe the total disturbance and state variables of the system in real time;

[0060]

[0061] Where z = [z1, z2] T Let x be the observed variable, e0 = x1 - z1 = y - z1 be the observation error, and G = [g1, g2]. T It is the observer gain, and the observer tracking form is z1(t)-x1(t), z2(t)-x2(t).

[0062] The observer transfer function can be derived from equation (6), and the characteristic polynomial of the observer can then be taken as:

[0063] s 2+g1s+g2=(s+ω0) 2 (7)

[0064] To ensure that both roots of the observer's characteristic equation lie at -ω0, we take g1 = 2ω0.

[0065] Where ω0 is the observer bandwidth;

[0066] S4. Based on equations (4) and (6), the converter controller is defined as follows:

[0067]

[0068] Where u0 is a closed-loop feedback control, the feedback controller of the outer loop of the converter voltage is considered to be a proportional controller, that is:

[0069] u0 = k p (E ref -y) (9)

[0070] Where, k p E is the gain of the proportional controller. ref This is a reference value for output power.

[0071] At 1 second, a periodic sinusoidal disturbance occurs on the load side of the bidirectional interleaved converter. The output voltage waveform of the converter using active disturbance rejection control at this time is as follows: Figure 4 As shown, it can be seen that the active disturbance rejection controller has insufficient ability to suppress periodic sinusoidal disturbances, resulting in large fluctuations in the output voltage.

[0072] S5. The quasi-resonant controller features zero steady-state error tracking of sinusoidal signals and has a large gain at the resonant frequency. It can control signals of specific frequencies and is an effective method for suppressing periodic disturbances. Its transfer function is as follows:

[0073]

[0074] By incorporating the quasi-resonant controller into the active disturbance rejection control (ADRC), we obtain the following improved ADRC proportional controller based on quasi-resonant control:

[0075]

[0076] The block diagram of the resonant improved active disturbance rejection control is as follows: Figure 3 As shown;

[0077] After adding a quasi-resonant controller to the active disturbance rejection controller, the converter output voltage waveform will react to periodic sinusoidal disturbances occurring on the load side as follows: Figure 5As shown, it can be seen that the bidirectional interleaved converter based on quasi-resonant control has a strong ability to suppress periodic sinusoidal disturbances, which greatly reduces the output voltage fluctuation.

[0078] Therefore, this invention employs the aforementioned voltage regulation method for bidirectional interleaved converters based on quasi-resonant control, solving the problem of weak suppression capability of active disturbance rejection controllers against periodic disturbances. This invention can be applied to various DC-DC converters, thereby improving the performance of the controlled object under periodic disturbances. This invention is simple, practical, and widely applicable.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control, characterized in that: Includes the following steps: S1. Construct the state-space equations of the bidirectional interleaved converter; S2. A dual closed-loop control structure based on the voltage outer loop and the current inner loop is designed for the bidirectional interleaved converter. First, the super-twisting sliding mode control algorithm is adopted for the current inner loop, and the power relationship of the current inner loop of the converter is given. S3. Based on the current inner loop power relationship obtained in step S2, use the linear active disturbance rejection control theory to design an extended state observer to estimate the total internal and external disturbances of the linear active disturbance rejection control system. S4. For the total internal and external disturbances of the linear active disturbance rejection control system obtained in step S3, design a proportional controller to control the unity-gain first-order system based on the pre-selected control bandwidth. S5. For the active disturbance rejection control proportional controller obtained in step S4, by adding the transfer function of the quasi-resonant controller, an improved active disturbance rejection control proportional controller based on quasi-resonant control is obtained, completing the design process of the extended state observer based on the improved quasi-resonant control and performing voltage regulation, thereby realizing the design process of the entire bidirectional interleaved converter voltage regulation method based on quasi-resonant control.

2. The voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control according to claim 1, characterized in that: In step S1, its state-space equation is: Wherein, L1, L2 are two input inductance values of the converter; r L1 , r L2 are the parasitic resistances of the two input inductances; C is the output capacitance value of the converter; i L1 , i L2 are the current values flowing through the two inductances; v o is the output voltage of the converter; d1, d2 are the duty cycles of the two switches of the converter.

3. The voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control according to claim 2, characterized in that: In step S2, the power relationship of the inner current loop is as follows: Among them, W E It is the energy stored in the capacitor, P DG It is the converter input power, P Loss It is the converter power loss, P o This is the converter's rated load power, including line loss P. Line and load power P R Two parts.

4. The voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control according to claim 3, characterized in that: In step S3, the total internal and external disturbances of the linear active disturbance rejection control system are designed as follows: Where y = W E u = I Lref f0 represents the total disturbance of the converter system.

5. The voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control according to claim 4, characterized in that: In step S4, the proportional controller is as follows: u0=k p (E ref -y) Where, k p E is the gain of the proportional controller. ref This is a reference value for output power.

6. The voltage regulation method for a bidirectional interleaved converter based on quasi-resonant control according to claim 5, characterized in that: In step S5, the active disturbance rejection proportional controller based on the quasi-resonant control improvement is as follows: Among them, G c It is the transfer function of the quasi-resonant controller.

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