Adaptive damping ratio control method for ship pulse power load buck converter

Abstract

An adaptive damping ratio control method for a Buck converter under a ship's pulsed power load is disclosed. This method establishes a single-input, single-output closed-loop control system for the parallel Buck converter. After obtaining the initial damping ratio and natural oscillation frequency, transient and steady-state response designs are performed. After verification of control stability, the optimized duty cycle is further adjusted to obtain a final duty cycle that simultaneously considers voltage regulation and current sharing control, thus achieving current sharing control of the parallel converter. This invention eliminates the nonlinear saturation of time-varying input and duty cycle by introducing a voltage-like loop. A second-order single-input, single-output system is established between the output voltage and its reference value. The control problem of uncertain load disturbances is transformed into a damping ratio control problem of a second-order system, allowing the output voltage response performance to be precisely adjusted directly through the damping ratio, independent of control parameters, and suppressing input voltage disturbances. Furthermore, this invention can achieve current sharing control of the parallel converter through additional duty cycle adjustment without affecting voltage regulation performance.

Description

Technical Field

[0001] This invention relates to a technology in the field of ship control, specifically an adaptive damping ratio control method for a ship pulse power load Buck converter. Background Technology

[0002] Shipboard pulsed power loads are characterized by instantaneous power jumps and continuous periodic operation, causing instantaneous drops and continuous disturbances in the output voltage of the interface converter during operation. Therefore, converter control is crucial for achieving rapid output voltage regulation. When using linear control methods, the converter's voltage regulation performance shifts with the steady-state operating point, failing to meet the control requirements for rapid voltage regulation. When using nonlinear control methods, while improving output voltage regulation performance, it introduces dependence on control parameters and makes it difficult to design open-loop cutoff frequencies to reduce static errors in the output voltage. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention proposes an adaptive damping ratio control method for Buck converters operating under pulsed power loads on ships. This method enables rapid voltage regulation after transient voltage drops and sustained disturbances in the converter's output voltage caused by pulsed power loads. By introducing a voltage-like loop, the nonlinear saturation of time-varying inputs and duty cycles is eliminated. A second-order single-input, single-output system is established between the output voltage and its reference value. This transforms the control problem of uncertain load disturbances into a damping ratio control problem for a second-order system. Consequently, the output voltage response performance can be precisely adjusted directly through the damping ratio, independent of control parameters, and it also suppresses input voltage disturbances. Furthermore, this invention can achieve current sharing control of parallel converters without affecting voltage regulation performance through additional duty cycle adjustment.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to an adaptive damping ratio control method for a Buck converter under pulsed power load on a ship, comprising the following steps:

[0006] Step 1) Establish a single-input single-output closed-loop control system for the parallel Buck converter to obtain the initial damping ratio and natural oscillation frequency;

[0007] Step 2) Perform transient response design, achieve adaptive damping ratio adjustment through control parameter design, adjust the initial damping ratio to the ideal damping ratio, and analyze the influence of the initial value of the output voltage on the transient response;

[0008] Step 3) Perform steady-state response design, limit the upper limit of control parameter values ​​by designing the open-loop cutoff frequency, and obtain the optimized duty cycle to achieve output voltage regulation;

[0009] Step 4) Verify the control stability based on the control parameter values ​​obtained in Step 2 and Step 3;

[0010] Step 5) Further adjust the optimized duty cycle obtained in Step 3) to obtain the final duty cycle that simultaneously considers voltage regulation and current sharing control, thereby realizing the current sharing control of the parallel converter. Technical effect

[0011] Compared to existing technologies, this invention transforms the control problem of uncertain load disturbances into a damping ratio control problem, enabling precise adjustment of the output voltage transient response performance directly through the damping ratio. This approach is applicable to uncertain and varying loads and is parameter-independent. The control design utilizes nonlinear saturation of the duty cycle to ensure a larger natural oscillation frequency as the output voltage approaches the reference value, which helps reduce the impact of the initial output voltage state on the transient response and improves the resistance to input voltage disturbances. Through open-loop cutoff frequency and open-loop gain design, this invention effectively suppresses output voltage disturbances during steady-state processes and reduces static errors. Furthermore, the parallel converters maintain good output current balance under different load power conditions. Attached Figure Description

[0012] Figure 1 This is a flowchart of the present invention;

[0013] Figure 2 This is a schematic diagram of a dual closed-loop control system.

[0014] Figure 3 This is a schematic diagram of a second-order system block diagram;

[0015] Figure 4 Schematic diagram of step response under different damping ratios;

[0016] Figure 5 For K vi With ω n With v o A schematic diagram of the changing dynamic curve;

[0017] Figure 6 A schematic diagram of a single-input, single-output s-domain closed-loop system;

[0018] Figure 7 This is a schematic diagram of the output voltage under input voltage disturbance.

[0019] Figure 8 For the open-loop transfer function G o A schematic diagram of the Bode plot of (s);

[0020] Figure 9 This is a schematic diagram of the transient and steady-state output voltages;

[0021] Figure 10This is a schematic diagram of the hardware experimental platform;

[0022] Figure 11 This is a schematic diagram of the transient response of a parallel converter;

[0023] In the figure: (a) Schematic diagram of converter output voltage, (b) Schematic diagram of pulse power load power step;

[0024] Figure 12 This is a schematic diagram of the output current of a parallel converter;

[0025] In the figure: (a) Schematic diagram considering flow sharing control, (b) Schematic diagram without considering flow sharing control;

[0026] Figure 13 This is a schematic diagram of the transient response of a pulsed power load with a power step.

[0027] In the figure: (a) Schematic diagram of converter output voltage, (b) Schematic diagram of output current. Detailed Implementation

[0028] like Figure 1 As shown in the figure, this embodiment relates to an adaptive damping ratio control method for Buck converters used in ship pulse power loads, specifically including:

[0029] Step 1) Establish a single-input single-output closed-loop control system for the parallel Buck converter and obtain the initial damping ratio and natural oscillation frequency.

[0030] The dynamic process of the parallel Buck converter is as follows: Where: v s and v o Let i be the input voltage and output voltage of the i-th converter. Li and i oi Let s be the inductor current and output current of the i-th converter; i This is the control signal for the gate device, corresponding to a duty cycle of d. i L i and C i It consists of the branch inductance and the output capacitor, R i This represents the equivalent resistance at the output terminal, with a total of m Buck converters connected in parallel. The output current balance of the parallel converters is obtained as follows. Where R is the total equivalent resistance of the output terminal.

[0031] like Figure 2 As shown, the outer voltage loop passes through v o Its reference value deviation e v (t) Generated inductor current reference value The inner current loop passes through the current deviation ei (t) Generates the PWM signal. The derivative of the voltage loop is obtained as follows: Figure 3 A voltage loop, the output of which is... Convert to its derivative For the dynamic process of parallel Buck converter v o Take the second derivative and substitute it. The transformed second-order system.

[0032] The output of the second-order system of the transformation has an uncertain load R. i Except for certain types that are difficult to predict accurately. Analogous to the small-signal model of a converter, the second-order system processes the output load as follows: within a very short time (such as one to several control cycles), R i Keep constant and by R i =v o / i oi Obtain, compare the actual load with R i The error is considered as a disturbance term ε in response to the output voltage. v Suppression is achieved by controlling the high-frequency attenuation of the control method.

[0033] The voltage loop-like representation of the transformed second-order system is derived. That is, there exists K vi and K vp Able to Convert to v o and The relevant controlled sources, and the time-domain expression of the output voltage of the i-th converter.

[0034] Due to the parallel converter's v s and v o Similarly, in order to ensure the inductor voltage With the same range of variation, each converter obtains the same K. vi and K vp Therefore, the time-domain expression for the output voltage of the parallel converter is...

[0035] By employing a voltage loop-like transformation, a second-order equation is established between the output voltage and its reference value, eliminating the time-varying input voltage and mapping the nonlinear saturation of the duty cycle to K. vi and K vp The range of values ​​for .

[0036] The single-input single-output closed-loop control system established in step 1 satisfies:

[0037] The dynamic characteristics of the system are determined by Determine, where: ζ is the damping ratio, ω n ω is the natural oscillation frequency. nWith K vi As K increases, the dynamic response increases, resulting in a faster response at the same damping ratio; ζ increases with K vi Increasing or decreasing the response will increase the likelihood of overshoot oscillations.

[0038] Step 2) Perform transient response design, implement adaptive damping ratio adjustment through control parameter design, adjust the initial damping ratio to the ideal damping ratio, and analyze the influence of the initial output voltage value on the transient response, specifically including:

[0039] 2.1) Adaptive adjustment of damping ratio: For single input Single output (v o For a second-order system, when ζ < 1, the system is underdamped, and the input amplitude is... The step response exhibits overshoot and oscillation; when ζ > 1, the system is overdamped, and the response settling time increases with the damping ratio; when ζ = 1, the system is critically damped, achieving a fast and smooth step response. For uncertain varying loads, a constant K... vi and K vp This can lead to underdamping or overdamping of the system, making it impossible to guarantee that the output voltage will quickly and smoothly adjust to the reference value during transient processes. On the other hand, K vp Essentially, this manifests as differential negative feedback control of the system, without altering the natural oscillation frequency ω. n The damping ratio can be dynamically adjusted via K. vi and K vp The parameter design allows ζ to be adjusted to the ideal damping ratio ζ. * =1, to achieve adaptive damping ratio control.

[0040] This embodiment uses ω n Taking a damping rate of 1000 rad / s as an example, the step response of a second-order system under different damping ratios is as follows: Figure 4 As shown.

[0041] 2.2) Control parameter design refers to: the system's open-loop gain G K =ω n / 2ζ With K vi Increase and increase, and at K vp The maximum value is reached when K = 0, so K is increased. vi This is beneficial for improving response performance and reducing static error. To obtain high open-loop gain, K... vi It is initialized to its maximum value, with an initial damping ratio of ζ0 = 1 / (2RCω). n In order to adjust the initial damping ratio ζ0 to the ideal damping ratio ζ * =1,K vp The value is When ζ0≥ζ * No need to introduce differential negative feedback control Kvp At this point, the damping ratio has no further downward adjustment range; if ζ0 < ζ * Through K vp The damping ratio can be adjusted to ζ. * .

[0042] like Should meet To increase the inductor current i Li And then through the current difference i Li -i oi Adding v to charge the capacitor o , The maximum value appears in d i =1; if Should meet To reduce inductor current i Li , The minimum value appears in d i =0. At this point, the nonlinear saturation of the duty cycle is mapped to K. vi The range of values ​​for should satisfy: Where: K max K under open-loop cutoff frequency constraint vi The upper limit of K; min(·) is the minimum value operator, which guarantees that K can take the maximum value. vi Always subject to K max The constraint; ε is a local minimum close to 0 (e.g., taking ε = 10). -2 ), to avoid the existence of K in the damping ratio expression vi =0.

[0043] When K vi When K reaches its maximum value, for the same input voltage, vi and ω n With v o Changing dynamic curves such as Figure 5 As shown, when v o Approaching K vi Limited by K max Conversely, K vi It is limited by the nonlinear saturation of the duty cycle.

[0044] 2.3) Influence of Initial Output Voltage Value on Transient Response: The initial state of the output voltage during a transient process is not zero, so the influence of the initial state on the transient response needs to be analyzed. When the system's damping ratio passes through K... vi and K vp Adjust to the ideal damping ratio ζ * When = 1, the transient response is analyzed in the time domain to obtain the time domain solution. Where: the variable band (t) represents the value at time t, t n v is the time of the nth control cycle.o (t0) and v at initial time zero o and Thanks to the nonlinear saturation of the duty cycle, ω n With v o Approaching Constantly increasing, such as Figure 5 As shown, for dynamically increasing ω n The initial state of the output voltage does not cause overshoot oscillations in the transient response of the second-order system, which effectively suppresses the influence of the initial state of the output voltage on the transient response. The suppression capability increases with v o Approaching Continuously improving.

[0045] To suppress the effects of input voltage disturbances, ω should be ensured. n In v o Approaching The time gradually increases. Define the current time as the j-th control cycle. At that time, K vi The upper limit of the value is not affected by v s The impact; when In order to obtain ω n (t j )≥ω n (t j-1 ), Δv s (t j ) should meet Where: Δv o (t j ) and Δv s (t j ) represent the control cycles from j-1 to j, respectively. o and v s The change in Δv within a single control cycle o (t j ) can be exchanged for Δv s (t j The allowable perturbation amount of ω makes ω n (t j )≥ω n (t j-1 It can still meet the requirements.

[0046] Therefore, as the output voltage increases, the maximum allowable disturbance of the input voltage increases, and the control method's ability to suppress input voltage disturbances also improves. If the input voltage is disturbed near its rated value, the positive disturbance can relatively compensate for the influence of the negative disturbance; a more serious situation occurs when the input voltage continues to drop during the output voltage increase process, which increases the response adjustment time and the risk of overshoot.

[0047] Step 3) Perform steady-state response design, limit the upper limit of control parameter values ​​by designing the open-loop cutoff frequency, and obtain the optimized duty cycle for converter output voltage regulation, specifically including:

[0048] 3.1) Open-loop cutoff frequency design. In steady state, R and K... vi and K vp Constant. Through s-domain transformation, the single-input single-output closed-loop system whose output voltage and reference value are obtained is shown below. Figure 6 Closed-loop transfer function The system's static error decreases as the open-loop gain increases, but excessively large open-loop gain may lead to system instability. Furthermore, since the converter is modeled using an average model, the control method should consider the open-loop cutoff frequency design. The open-loop cutoff angular frequency is defined as ω. c Open-loop transfer function In s=jω c amplitude at Define the control frequency of the converter as f s And the open-loop cutoff frequency f c Restricted to af s (Generally, a < 1 / 3 is guaranteed; for example, a = 1 / 10 to 1 / 5 can be taken). When considering open-loop cutoff frequency limitations

[0049] 3.2) Achieve optimized duty cycle for voltage regulation. This is achieved through K... max Restriction K vi The upper limit of the value, substituted into K vi K vp and to Obtain the optimized duty cycle of the i-th converter

[0050] Step 4) Based on the control parameter values ​​obtained in Steps 2 and 3, verify the control stability, specifically including:

[0051] Selecting the state vector Input vector Establish the state-space equations of the parallel converter in: A and B are the state matrix and input matrix, respectively. The eigenvalues ​​of matrix A are... According to the stability condition, the eigenvalues ​​of matrix A should all have negative real parts, that is, K is guaranteed to have a negative real part. vi >0 and K vp >-L / R. Correspondingly, the damping ratio should satisfy ζ>0. Due to the existence of K vi >0 and K vp ≥0. Therefore, K vi and K vpThe value of ensures the control stability of the parallel converter, and the stability is not affected by the inductance and capacitance values ​​and parameter perturbations of the converter.

[0052] Step 5) Implement current sharing control for the parallel converter. Further adjust the optimized duty cycle obtained in Step 3) to obtain the final duty cycle that simultaneously considers voltage regulation and current sharing control. Specifically, this includes:

[0053] The output current of a Buck converter can be considered to be provided by the DC component of the inductor current, while the AC component of the inductor current enters the output capacitor circuit. Therefore, current sharing control can be achieved by adjusting the duty cycle to change the inductor current. In actual operation, discrete control is usually used. The inductor current of the i-th converter in the (n+1)-th control cycle... t n+1 Average inductor current of parallel converter at any time In order to reduce t n+1 The output current is constantly unbalanced, when K vi and K vp When determined, it can be maintained The equation balance enables additional current regulation while avoiding its impact on voltage regulation, thus ensuring... like Through Δd i (t n If Δd > 0, the inductor current increases; conversely, if Δd > 0, the inductor current is guaranteed. i (t n )<0. When considering flow sharing control, the duty cycle is ultimately corrected to d'. i (t n )=d i (t n )+Δd i (t n ).in: If d' i (t n If duty cycle saturation occurs, Δd should be reduced proportionally. i (t n ).

[0054] Through specific experiments, different converter power supply structures were established and analyzed. The single converter power supply structure was used to illustrate: transient response during startup, the impact of input voltage disturbances, and steady-state response analysis; the parallel converter power supply structure was used to illustrate: voltage regulation and current balancing of the converter during sudden power changes in pulsed power loads, and a comparison with nonlinear control methods.

[0055] The power supply structure based on the Buck converter is shown in Table 1. The control parameters of the converter are: Control frequency f s =20kHz(T) s =5e-5 s); Considering the open-loop cutoff frequency f c =1 / 10f s That is, a = 1 / 10.

[0056] Table 1 Parameters of the Buck Converter

[0057] Furthermore, the negative impedance characteristic of a constant power load increases control complexity and is often used to verify control effectiveness. The pulse power load model of this invention uses a constant power load P. o With constant impedance load R d =1000Ω parallel structure, by changing P o Simulate the power surge of a pulsed power load.

[0058] A power supply model for a single converter was built based on the Simulink platform to verify the converter's transient response under input voltage disturbances and to perform steady-state response analysis. The input voltage disturbance scenario was set, and the parameters are shown in Table 2.

[0059] Table 2 Input voltage disturbance scenarios

[0060] In the table, rand(·) is a random function with an output range of [0,1].

[0061] 1) Transient response to input voltage disturbance: The output voltage of the converter during the startup phase, such as... Figure 7 As shown, the converter starts under no-load conditions when 0 ≤ t ≤ 1 ms, providing part of the output voltage; a constant power load is connected when t > 1 ms. It can be seen that under different input voltage disturbance scenarios, the adaptive damping ratio control can achieve a fast and smooth output voltage response to the reference value of 400V, with a settling time t... r Approximately 4.60ms; for the relatively severe disturbance scenario 3, the input voltage v s The continuous drop caused ω n The transient response performance is relatively small, and there is a slight decrease, but precise voltage regulation can still be achieved.

[0062] 2) Steady-state response analysis: When v o Stable at Nearby, load P o The equivalent resistances for 10kW, 50kW, and 100kW are 16Ω, 3.2Ω, and 1.6Ω, respectively, and the natural oscillation frequency ω is... n The values ​​are 12566 rad / s, 12568 rad / s, and 12574 rad / s, respectively. The open-loop transfer function G... oBode plot of (s), as follows Figure 8 As shown, G o1 (s), G o2 (s) and G o3 (s) represent the three loads under adaptive damping ratio control. o (s); G' o1 (s), G' o2 (s) and G' o3 (s) represents G without adaptive damping ratio control. o (s), with initial damping ratios of ζ = 0.0025, ζ = 0.0125 and ζ = 0.0249, respectively.

[0063] Without adaptive damping ratio control, G' o1 (s), G' o2 (s) and G' o3 (s) has a higher open-loop cutoff frequency, which meets the set f c =2kHz. However, the fast response of an underdamped system implies overshoot and oscillation in the time domain; with adaptive damping ratio control, through K vp Dynamically adjust the damping ratio to ζ * =1, the system's phase stability margin increases, and it also possesses precise voltage regulation characteristics. At t=0.2s, the load P... o The output voltage during the transient and steady-state processes when the power output jumps from 10kW to 50kW is as follows: Figure 9 As shown, during the transient process, when the ideal damping ratio ζ * =0.5, the output voltage of the underdamped system recovers to Overshoot oscillations occur; when the ideal damping ratio ζ * =1.0, enabling rapid and smooth adjustment of the output voltage; when the ideal damping ratio ζ * =1.5, the response settling time of the overdamped system becomes longer. During steady-state operation, the open-loop gain G... K =ω n As can be seen from / 2ζ, the open-loop gain decreases as the damping ratio increases, and the static error Δv of the output voltage... e Consequently, the damping ratio increases. * =0.5 increased to ζ * =1.0 and ζ * =1.5, Δv e The voltage was increased from 0.15V to 0.30V and 0.50V. Therefore, ζ * =1.0 can simultaneously take into account both transient and steady-state response performance.

[0064] The response performance of the parallel converter: A simulation was constructed using the hardware-in-the-loop RT-LAB platform and a Xilinx FPGA ZYNQ7020 controller. Figure 10The hardware-in-the-loop system is shown. The AN706 board is the controller's sampling module, connected to the RT-LAB AO board for input sampling; the AN9767 board generates control signals for the gate devices, which are fed back to the converter model via the RT-LAB DI board. For the parallel converter power supply structure, transient response performance is verified through different power surges in a pulsed power load. The converter's transient response under different power surges is as follows: Figure 11 As shown, P o The output voltage drop Δv when jumping from 10kW to 80kW and 100kW od The output voltages are -20.78V and -40.77V respectively; both output voltages can recover quickly and smoothly to [the specified values]. Recovery time t r The times were 1.90ms and 2.35ms, respectively.

[0065] Parameter differences and induced resistance in parallel converters lead to unbalanced output current. When the controller includes additional current sharing control, the parallel output current can maintain good current sharing, such as... Figure 12 As shown in (a); without considering current sharing control, the parallel output current has a large deviation, such as Figure 12 As shown in (b), the deviation of the output current gradually increases over time. For converters that bear excessive output current for a long time, the overall reliability will decrease due to heat generation.

[0066] To verify the control effect under different initial conditions, a response test was conducted by continuously stepping the load power. The power of the pulsed power load continuously stepped from 50kW to 200kW, and the transient response of the converter was as follows: Figure 13 As shown, the single-step power of the load is 50kW, and the output voltage drop is Δv. od With voltages of approximately -15.0V and -14.0V, the converter can achieve fast and smooth voltage regulation; the parallel output current deviation is small under different load power, ensuring good current balancing effect.

[0067] Compared with existing technologies, this invention first transforms the control problem of uncertain load disturbances into a damping ratio control problem, enabling the transient response performance of the output voltage to be precisely adjusted directly through the damping ratio. This makes it applicable to uncertain and changing loads and is parameter-independent. Simultaneously, the nonlinear saturation of the duty cycle is utilized in the control process to ensure a larger natural oscillation frequency when the output voltage approaches the reference value, thereby improving the control method's ability to suppress input voltage disturbances. Finally, the control method effectively suppresses output voltage disturbances and reduces static errors during steady-state processes through open-loop cutoff frequency and open-loop gain design.

[0068] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. An adaptive damping ratio control method for a Buck converter under a ship's pulsed power load, characterized in that, Includes the following steps: Step 1) Establish a single-input single-output closed-loop control system for the parallel Buck converter to obtain the initial damping ratio and natural oscillation frequency; Step 2) Perform transient response design, achieve adaptive damping ratio adjustment through control parameter design, adjust the initial damping ratio to the ideal damping ratio, and analyze the influence of the initial value of the output voltage on the transient response; Step 3) Perform steady-state response design, limit the upper limit of control parameter values ​​by designing the open-loop cutoff frequency, and obtain the optimized duty cycle to achieve output voltage regulation; Step 4) Verify the control stability based on the control parameter values ​​obtained in Step 2 and Step 3; Step 5) Further adjust the optimized duty cycle obtained in Step 3) to obtain the final duty cycle that simultaneously considers voltage regulation and current sharing control, thereby realizing the current sharing control of the parallel converter; The dynamic process of the parallel Buck converter is as follows: , where: v s and v o Let i be the input voltage and output voltage of the i-th converter. Li and i oi Let s be the inductor current and output current of the i-th converter; i This is the control signal for the gate device, corresponding to a duty cycle of d. i L i and C i It consists of the branch inductance and the output capacitor, R i This represents the equivalent resistance at the output terminal. There are m Buck converters connected in parallel. The value is obtained based on the output current balance of the parallel converters. Where R is the total equivalent resistance of the output terminal. ; The voltage outer loop passes through v o Its reference value deviation Generate inductor current reference value The inner current loop passes through the current deviation. A PWM signal is generated, and a voltage-like loop is obtained by differentiating the voltage loop. The output of the voltage-like loop is then determined by... Convert to its derivative For the dynamic process of parallel Buck converter v o Take the second derivative and substitute it. Thus, a transformed second-order system is obtained; The output of the second-order system of the transformation has an uncertain load R. i Excluding certain types that are difficult to predict accurately, its handling of the output load is as follows: In one to several control cycles, R i Keep constant and by R i =v o / i oi Obtain, compare the actual load with R i The error is considered as a disturbance term ε in response to the output voltage. v Suppression is achieved by controlling the high-frequency attenuation of the control method; The voltage loop-like representation of the transformed second-order system is derived. That is, there exists K vi and K vp Able to Convert to v o and The relevant controlled sources, and the time-domain expression of the output voltage of the i-th converter. ; Due to the parallel converter's v s and v o Similarly, in order to ensure the inductor voltage With the same range of variation, each converter obtains the same K. vi and K vp Therefore, the time-domain expression of the output voltage of the parallel converter is... ; By employing a voltage loop-like transformation, a second-order equation is established between the output voltage and its reference value, eliminating the time-varying input voltage and mapping the nonlinear saturation of the duty cycle to K. vi and K vp The range of values ​​for .

2. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 1, characterized in that, The single-input single-output closed-loop control system established in step 1 satisfies the following: the dynamic characteristics of the system are determined by... Determine, where: ζ is the damping ratio, ω n ω is the natural oscillation frequency. n With K vi As K increases, the dynamic response increases, resulting in a faster response at the same damping ratio; ζ increases with K vi Increasing or decreasing the response will increase the likelihood of overshoot oscillations.

3. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 1, characterized in that, Step 2 specifically includes: 2.1) Adaptive adjustment of damping ratio: For single-input ( Single output (v) o For a second-order system, when ζ < 1, the system is underdamped, and the input amplitude is... The step response will exhibit overshoot and oscillation; when ζ>1, the system is overdamped, and the response settling time increases with the damping ratio; when ζ=1, the system is critically damped, achieving a fast and smooth step response. For uncertain changing loads, a constant K... vi and K vp This can lead to underdamping or overdamping of the system, making it impossible to guarantee that the output voltage will quickly and smoothly adjust to the reference value during transient processes. On the other hand, K vp Essentially, this manifests as differential negative feedback control of the system, without altering the natural oscillation frequency ω. n The damping ratio can be dynamically adjusted via K. vi and K vp The parameter design allows ζ to be adjusted to the ideal damping ratio. =1, achieving adaptive damping ratio control; 2.2) Control parameter design refers to: the system's open-loop gain G K = With K vi Increase and increase, and at K vp The maximum value is reached when K = 0, and K is increased. vi It is beneficial to improve response performance and reduce static error; K vi Initialize to the maximum value to obtain high open-loop gain, initial damping ratio is ζ0= In order to adjust the initial damping ratio ζ0 to the ideal damping ratio =1,K vp The value is When ζ0≥ No need to introduce differential negative feedback control K vp At this point, the damping ratio has no further downward adjustment range; if Through K vp Adjust the damping ratio to ; 2.3) Influence of Initial Output Voltage on Transient Response: The initial state of the output voltage during a transient process is not zero. It is necessary to analyze the influence of the initial state on the transient response. When the system's damping ratio passes through K... vi and K vp Adjust to ideal damping ratio When = 1, the transient response is analyzed in the time domain to obtain the time domain solution. Where: the variable band (t) represents the value at time t, t n The time of the nth control cycle. and v at initial time zero o and Thanks to the nonlinear saturation of the duty cycle, ω n With v o Approaching Continuously increasing, for dynamically increasing ω n The initial state of the output voltage does not cause overshoot oscillations in the transient response of the second-order system, which effectively suppresses the influence of the initial state of the output voltage on the transient response. The suppression capability increases with v o Approaching Continuously improving.

4. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 3, characterized in that, when It should meet To increase the inductor current i by ≥0 Li And then through the current difference i Li -i oi Adding v to charge the capacitor o , The maximum value appears in d i =1; if It should meet ≤0 to reduce inductor current i Li , The minimum value appears in d i =0; Map the nonlinear saturation of the duty cycle to K vi The range of values ​​for satisfies: , where: K max K under open-loop cutoff frequency constraint vi The upper limit of the possible values; It is the minimum value operator, which guarantees K. vi Always subject to K max The constraint; ε is a minimum value close to 0 to avoid the existence of K in the damping ratio expression. vi =0; When K vi When the maximum value is obtained, for the same input voltage, when v o Approaching K vi Limited by K max Conversely, K vi Limited by the nonlinear saturation of the duty cycle; To suppress the effects of input voltage disturbances, ω should be ensured. n In v o Approaching The time gradually increases, and the current time is defined as the j-th control cycle. When v o ≥ At that time, K vi The upper limit of the value is not affected by v s The effect; when v o < In order to obtain ω n (t j )≥ω n (t j-1 ), Δv s (t j ) should meet , where: Δv o (t j ) and Δv s (t j ) represent the control cycles from j-1 to j, respectively. o and v s The change in Δv within a single control cycle o (t j ) can be exchanged for Δv s (t j The allowable perturbation amount of ω makes ω n (t j )≥ω n (t j-1 It can still meet the requirements.

5. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 1, characterized in that, Step 3 specifically includes: 3.1) Open-loop cutoff frequency design, under steady-state conditions, R, K vi and K vp A constant, s-domain transformation yields the output voltage and its reference value in a single-input, single-output closed-loop system. The closed-loop transfer function is... The static error of the system decreases as the open-loop gain increases, but excessive open-loop gain may lead to system instability. Meanwhile, since the converter is modeled using an average model, the control method should consider the design of the open-loop cutoff frequency, defined as ω. c Open-loop transfer function In s=jω c amplitude at Define the control frequency of the converter as f. s And the open-loop cutoff frequency f c Restricted to af s (Generally, a < 1 / 3 is guaranteed; if a = 1 / 10 to 1 / 5 is taken), when considering the open-loop cutoff frequency limitation... ; 3.2) To achieve optimized duty cycle for voltage regulation, K... max Restriction K vi The upper limit of the value, substituted into K vi K vp and to The optimized duty cycle of the i-th converter is obtained. .

6. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 1, characterized in that, Step 4 specifically includes: selecting the state vector x=[ ,v o ] T Input vector u= Establish the state-space equations of the parallel converter. ,in: Let A and B be the state matrix and the input matrix, respectively, and let A be the eigenvalues ​​of matrix A. According to the stability condition, the eigenvalues ​​of matrix A should all have negative real parts, that is, it is guaranteed that K vi >0 and K vp >-L / R, correspondingly, the damping ratio should satisfy ζ>0, due to the existence of K vi >0 and K vp ≥0, therefore, K vi and K vp The value of ensures the control stability of the parallel converter, and the stability is not affected by the inductance and capacitance values ​​and parameter perturbations of the converter.

7. The adaptive damping ratio control method for a ship pulse power load Buck converter according to claim 1, characterized in that, Step 5 specifically includes: The output current of the Buck converter can be considered to be provided by the DC component of the inductor current, while the AC component of the inductor current enters the output capacitor circuit. Therefore, current sharing control can be achieved by adjusting the duty cycle to change the inductor current. In actual operation, discrete control is usually adopted. In the (n+1)th control cycle, the inductor current of the i-th converter is... , t n+1 Average inductor current of parallel converter at any time In order to reduce t n+1 The output current is constantly unbalanced, when K vi and K vp When determined, it can be maintained The equation balance enables additional current regulation while avoiding its impact on voltage regulation, thus ensuring... =0, if i Li (t n+1 )< (t n+1 ), through Δd i (t n If Δd > 0, the inductor current increases; conversely, if Δd > 0, the inductor i (t n If the duty cycle is less than 0, then when considering flow sharing control, the duty cycle will be ultimately corrected to... =d i (t n )+Δd i (t n ),in: ,like If duty cycle saturation occurs, Δd should be reduced proportionally. i (t n ).

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