CN117134585A - Self-adaptive damping ratio control method for ship pulse power load Buck converter - Google Patents

Abstract

A self-adaptive damping ratio control method for ship pulse power load Buck converter includes such steps as creating a single-input single-output closed-loop control system for parallel Buck converter, obtaining initial damping ratio and natural oscillation frequency, transient response design and steady response design, verifying control stability, additionally regulating the obtained optimized duty ratio, and obtaining the final duty ratio considering voltage regulation and current-sharing control. In addition, the current sharing control of the parallel converter can be realized through additional duty ratio adjustment on the premise of not affecting the voltage regulation performance.

Description

Self-adaptive damping ratio control method for ship pulse power load Buck converter

Technical Field

The invention relates to a technology in the field of ship control, in particular to a self-adaptive damping ratio control method for a ship pulse power load Buck converter.

Background

The ship pulse power load has the characteristics of instantaneous power step and continuous periodic operation, and can cause instantaneous drop and continuous disturbance of the output voltage of the interface converter during operation. Inverter control is therefore critical to achieving rapid regulation of the output voltage. When the linear control method is adopted, the voltage regulation performance of the converter deviates along with the steady-state operation point, and the control requirement of quick voltage regulation cannot be met; when the nonlinear control method is adopted, control parameter dependence is brought while the output voltage regulation performance is improved, and the open-loop cut-off frequency design is difficult to carry out to reduce the static error of the output voltage.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a self-adaptive damping ratio control method for a ship pulse power load Buck converter, which realizes the rapid voltage regulation after the instantaneous drop and continuous disturbance of the output voltage of the converter caused by the pulse power load. By introducing a voltage-like ring, the nonlinear saturation of time-varying input and duty ratio is eliminated, a single-input single-output second-order system of output voltage and a reference value thereof is established, and the control problem of uncertain load disturbance is converted into the damping ratio control problem of the second-order system, so that the response performance of the output voltage can be accurately regulated directly through the damping ratio, is independent of control parameters, and has an inhibition effect on the input voltage disturbance. In addition, the current sharing control of the parallel converter can be realized through additional duty ratio adjustment on the premise of not affecting the voltage regulation performance.

The invention is realized by the following technical scheme:

the invention relates to a self-adaptive damping ratio control method of a ship pulse power load Buck converter, which comprises the following steps:

step 1), a single-input single-output closed-loop control system of a parallel Buck converter is established, and an initial damping ratio and a natural oscillation frequency are obtained;

step 2) performing transient response design, realizing self-adaptive damping ratio adjustment through control parameter design, adjusting the initial damping ratio to an ideal damping ratio, and analyzing the influence of an initial value of output voltage on transient response;

step 3) steady-state response design is carried out, the upper limit of the value of the control parameter is limited through open-loop cut-off frequency design, and the optimal duty ratio for realizing output voltage regulation is obtained;

step 4) verifying control stability according to the control parameter values obtained in the step 2 and the step 3;

and 5) carrying out additional adjustment on the optimized duty ratio obtained in the step 3) to obtain a final duty ratio which simultaneously considers voltage adjustment and current sharing control, and realizing current sharing control of the parallel converter.

Technical effects

Compared with the prior art, the method converts the control problem of uncertain load disturbance into the damping ratio control problem, so that the transient response performance of the output voltage can be accurately regulated directly through the damping ratio, and the method has applicability to uncertain load change and has no parameter dependence. The control design of the invention utilizes the nonlinear saturation of the duty ratio, ensures that the output voltage has larger natural oscillation frequency when approaching to the reference value, is beneficial to reducing the influence of the initial state of the output voltage on the transient response, and improves the capability of resisting the disturbance of the input voltage. The invention effectively suppresses the disturbance of the output voltage in the steady-state process and reduces the static error through the design of the open-loop cut-off frequency and the open-loop gain. In addition, the parallel converters can ensure good output current balance under different load powers.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic diagram of a dual closed loop control;

FIG. 3 is a schematic diagram of a second order system block diagram;

FIG. 4 is a graph showing step response at different damping ratios;

FIG. 5 is K _vi And omega _n With v _o A schematic of a dynamic curve of the change;

FIG. 6 is a schematic diagram of a single input single output s-domain closed loop system;

FIG. 7 is a schematic diagram of the output voltage under input voltage disturbance;

FIG. 8 is an open loop transfer function G _o The Bode pictorial intent of(s);

FIG. 9 is a schematic diagram of transient and steady state output voltages;

FIG. 10 is a schematic diagram of a hardware experiment platform;

FIG. 11 is a schematic diagram of the transient response of the parallel converter;

in the figure: (a) A converter output voltage schematic, (b) a pulsed power load power step schematic;

FIG. 12 is a schematic diagram of the output current of the parallel converter;

in the figure: (a) A current sharing control schematic diagram is considered, and (b) the current sharing control schematic diagram is not considered;

FIG. 13 is a schematic diagram of the transient response of a pulsed power load power step;

in the figure: (a) A converter output voltage schematic, (b) an output current schematic.

Detailed Description

As shown in fig. 1, this embodiment relates to a self-adaptive damping ratio control method suitable for a ship pulse power load Buck converter, which specifically includes:

step 1) a single-input single-output closed-loop control system of the parallel Buck converter is established, and an initial damping ratio and a natural oscillation frequency are obtained.

The dynamic process of the parallel Buck converter is as follows:wherein: v _s And v _o I is the input voltage and the output voltage of the ith converter _Li And i _oi Is the ithInductor current and output current of each converter; s is(s) _i Is a control signal of a gate device, and has a corresponding duty ratio d _i ；L _i And C _i Is the branch inductance and the output capacitance, R _i The equivalent resistance of the output end is represented, and m Buck converters are connected in parallel. According to the output current balance of the parallel converter, the +.>Wherein: r is the total equivalent resistance of the output end, +.>

As shown in fig. 2, the voltage outer loop passes v _o With reference value ofDeviation e of (2) _v (t) generating an inductor current reference value +.>The current inner loop passes through the current deviation e _i (t) generating a PWM signal. The voltage-like ring as shown in FIG. 3 is obtained by deriving the voltage ring, and the output of the voltage-like ring is composed of +.>To its derivative->V in dynamic process for parallel Buck converter _o Second order derivative and substitute +.>Obtaining a second-order system of conversion.

The output end of the second-order system of the conversion is uncertain load R _i Removing a particular type is difficult to predict accurately. The second order system processes the output load, like the small signal model of the converter, as follows: in a very short time (e.g. one to several control cycles), R _i Held constant and defined by R _i ＝v _o /i _oi Obtained by combining the actual load with R _i Is considered as a disturbance term epsilon in response to the output voltage _v The high-frequency band attenuation of the control method is used for suppressing.

Deriving a voltage-like loop representation of a transformed second-order systemI.e. K is present _vi And K _vp Can be->Conversion to and v _o And->The time domain expression of the output voltage of the ith converter +.>

V due to parallel converters _s And v _o In order to ensure the inductance voltageThe variation ranges are the same, and each converter obtains the same K _vi And K _vp . Thus, the time domain representation of the parallel converter output voltage

By voltage-like loop conversion, a second-order equation of the output voltage and a reference value thereof is established, the time-varying input voltage is eliminated, and the nonlinear saturation of the duty cycle is mapped to K _vi And K _vp Is a range of values.

The single-input single-output closed-loop control system established in the step 1 meets the following conditions:

dynamic characteristics of the system are defined byDetermining, wherein: zeta is the damping ratio，ω _n Is the natural oscillation frequency. Omega _n With K _vi Increasing and increasing, the same damping ratio has faster dynamic response; zeta with K _vi Increasing and decreasing, the response increases the likelihood of overshoot oscillations.

Step 2) performing transient response design, realizing self-adaptive damping ratio adjustment through control parameter design, adjusting an initial damping ratio to an ideal damping ratio, and analyzing the influence of an initial value of output voltage on transient response, wherein the method specifically comprises the following steps:

2.1 Adaptive adjustment of damping ratio): for single inputSingle output (v) _o ) Second order system, zeta<Under-damping of the system in the 1 time, and input amplitude is +.>Overshoot and ringing may occur in the step response of (a); when zeta is>1, the system is over-damped, and the response adjustment time is increased along with the increase of the damping ratio; when ζ=1 the system is critically damped, a fast smooth step response can be achieved. For an indeterminate varying load, a constant K _vi And K _vp The underdamping or the overdamping of the system can be caused, and the output voltage of the transient process can not be guaranteed to be quickly and smoothly adjusted to the reference value. On the other hand, K _vp Essentially represented by differential negative feedback control of the system without changing the natural oscillation frequency omega _n Dynamic adjustment of the damping ratio can be achieved. By K _vi And K _vp Can adjust ζ to ideal damping ratio ζ ^* =1, realizing adaptive damping ratio control.

The embodiment uses omega _n For example, =1000 rad/s, the step response of the second order system at different damping ratios is shown in fig. 4.

2.2 Control parameter design refers to: open loop gain G of system _K ＝ω _n 2 zeta with K _vi Increase and increase at K _vp Maximum value is obtained when=0, and K is increased _vi The method is beneficial to improving response performance and reducing static errors. To obtain high open loop gain，K _vi Initialized to maximum value and an initial damping ratio ζ ₀ ＝1/(2RCω _n ) The method comprises the steps of carrying out a first treatment on the surface of the To set the initial damping ratio ζ ₀ Adjusted to the ideal damping ratio ζ ^* ＝1，K _vp The value of (2) isWhen zeta is ₀ ≥ζ ^* Without introducing differential negative feedback control K _vp At this time, the damping ratio has no downward adjustment range; if ζ ₀ ＜ζ ^* Through K _vp The damping ratio can be adjusted to zeta ^* 。

If it isShould satisfy->To increase the inductance current i _Li And then through the current difference i _Li -i _oi Increasing v for capacitor charging _o ，/>The maximum value of (d) appearing at d _i =1; if->Should satisfy->To reduce the inductance current i _Li ，/>The minimum of (d) occurs at d _i =0. At this time, the nonlinear saturation of the duty ratio is mapped to K _vi The value range of (2) should satisfy:wherein: k (K) _max For K under open loop cut-off frequency limit _vi Upper limit of the value of (2); min (·) is the minimum operator, i.e. guarantee K _vi Always receive K _max Is a constraint of (2); epsilon is a minimum value close to 0 (e.g., epsilon=10 ^-2 ) To avoid the existence of K in the damping ratio expression _vi ＝0。

When K is _vi When the maximum value is taken, for the same input voltage, K _vi And omega _n With v _o The dynamic curve of the change is shown in FIG. 5, when v _o Approach toK _vi Is limited by K _max The method comprises the steps of carrying out a first treatment on the surface of the Conversely, K _vi Is limited by the nonlinear saturation of the duty cycle.

2.3 Effect of initial value of output voltage on transient response): the initial state of the transient process output voltage is not zero, and the influence of the initial state on transient response needs to be analyzed. When the damping ratio of the system is K _vi And K _vp Adjusted to the ideal damping ratio ζ ^* When=1, the transient response is analyzed by the time domain to obtain the time domain solutionWherein: the variable band (t) represents the value at time t, t _n Time of nth control period, v _o (t ₀ ) And->V at the initial zero time respectively _o And->Omega thanks to non-linear saturation of duty cycle _n With v _o Approach->Increasing, as shown in FIG. 5, for a dynamically increasing ω _n The initial state of the output voltage does not cause overshoot oscillation of the transient response of the second-order system, which effectively inhibits the influence of the initial state of the output voltage on the transient response, and the inhibition capability follows v _o Approach->And the lifting is continuous.

In order to suppress the influence of input voltage disturbance, ω should be ensured _n At v _o Approach toGradually increasing. Defining the current time as the j-th control period when +.>When K is _vi The upper limit of the value of (a) is not limited by v _s Is a function of (1); when->When, in order to obtain omega _n (t _j )≥ω _n (t _j-1 )，Δv _s (t _j ) Should satisfy->Wherein: deltav _o (t _j ) And Deltav _s (t _j ) The j-1 th to j-th control periods v _o And v _s The variation of (a), i.e. Deltav in a single control period _o (t _j ) Exchangeable for Deltav _s (t _j ) Is allowed to disturb such that ω _n (t _j )≥ω _n (t _j-1 ) Still can meet the requirements.

Therefore, as the output voltage increases, the maximum allowable disturbance amount of the input voltage increases, and the capability of the control method for suppressing the disturbance of the input voltage also increases. If the input voltage is disturbed near the rated value, the positive disturbance quantity can relatively compensate the influence of the negative disturbance quantity; a relatively harsh condition occurs in: the input voltage continues to drop during the boost of the output voltage, which increases the response time and the risk of overshoot.

Step 3) performing steady-state response design, limiting the upper limit of the value of the control parameter through open-loop cut-off frequency design, and obtaining the optimized duty ratio of the output voltage regulation of the converter, wherein the method specifically comprises the following steps:

3.1 Open loop sectionAnd (5) frequency stopping design. R, K at System steady state _vi And K _vp Constant. A single-input single-output closed loop system for obtaining output voltage and reference value thereof through s-domain transformation is shown in figure 6, and the closed loop transfer functionThe static error of the system decreases as the open loop gain increases, but excessive open loop gain may cause the system to destabilize; meanwhile, as the modeling of the converter adopts an average model, the control method should consider open loop cut-off frequency design. Definition of open-loop cut-off angular frequency as ω _c Open loop transfer function->At s=jω _c Amplitude of the region->Defining the control frequency of the converter as f _s And will open loop cut-off frequency f _c Limited to af _s (generally ensure a)<1/3, e.g. taking a=1/10 to 1/5).

Considering open loop cut-off frequency limitation

3.2 An optimized duty cycle for voltage regulation is achieved. By K _max Limit K _vi Is substituted into K _vi 、K _vp Andto->Obtaining an optimized duty cycle of the ith converter

And 4) verifying control stability according to the control parameter values obtained in the step 2 and the step 3, wherein the method specifically comprises the following steps:

selecting a state vectorInput vector->Establishing a state space equation for parallel convertersWherein: />A and B are the state matrix and the input matrix, respectively. Characteristic root of matrix A->The characteristic roots of matrix A should all have negative real parts, i.e. guarantee K, according to stability conditions _vi >0 and K _vp >-L/R. Correspondingly, the damping ratio should satisfy ζ>0. Due to the presence of K _vi >0 and K _vp And is more than or equal to 0. Thus, K is _vi And K _vp The control stability of the parallel converter is ensured, and the stability is not influenced by the inductance and capacitance values of the converter and the perturbation of parameters.

Step 5) realizing current sharing control of the parallel converters, and additionally adjusting the optimized duty ratio obtained in the step 3) to obtain a final duty ratio which simultaneously considers voltage adjustment and current sharing control, wherein the method specifically comprises the following steps:

the output current of the Buck converter can be considered to be provided by an inductor current dc component, which enters the output capacitor loop. Thus, current sharing control may be achieved by varying the inductor current through additional adjustments in the duty cycle. Actual operation typically employs discrete controls. Inductor current of the ith converter during the (n+1) th control periodt _n+1 Average inductor current of time-of-day parallel convertersTo reduce t _n+1 Unbalanced output current at time when K _vi And K _vp Can be determined by maintainingIs balanced, additional current regulation is achieved and the influence on the voltage regulation is avoided, i.e. guaranteed +.>If->By Δd _i (t _n )>0 increasing the inductor current; otherwise, guarantee Δd _i (t _n )<0. When current sharing control is considered, the duty ratio is finally corrected to d' _i (t _n )＝d _i (t _n )+Δd _i (t _n ). Wherein: />If d' _i (t _n ) Duty cycle saturation occurs and Δd should be reduced in equal proportion _i (t _n )。

Through specific experiments, different converter power supply structures are established for analysis. Wherein a single converter power architecture is used to illustrate: transient response at the starting stage, influence of input voltage disturbance and steady state response analysis; the parallel converter power supply structure is used to illustrate: voltage regulation, current balancing and comparison with nonlinear control methods of the converter when the pulse power load power is suddenly changed.

The parameters are shown in table 1 based on the power supply structure of the Buck converter. The control parameters of the converter are:control frequency f _s ＝20kHz(T _s ＝5e ^-5 s); consider the open loop cut-off frequency f _c ＝1/10f _s I.e. a=1/10.

Table 1 parameters of Buck converter

In addition, the negative impedance characteristic of a constant power load increases control complexity and is often used for verification of control effects. The pulse power load model adopts a constant power load P _o And constant impedance load R _d =1000Ω parallel structure by varying P _o Simulating a sudden power change of the pulsed power load.

And establishing a single converter power supply model based on the Simulink platform, verifying transient response of the converter when the input voltage is disturbed, and carrying out steady state response analysis. The set input voltage disturbance scene and parameters are shown in table 2.

TABLE 2 input Voltage disturbance scenario

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

1) Transient response of input voltage disturbance: the output voltage of the converter in the starting stage is shown in figure 7, wherein when t is more than or equal to 0 and less than or equal to 1ms, the converter is started in an idle state to provide part of output voltage; t is t>And a constant power load is connected at 1 ms. It can be seen that under different input voltage disturbance scenes, the adaptive damping ratio control can realize that the output voltage rapidly and smoothly responds to the reference value 400V, and the time t is regulated _r About 4.60ms; for a relatively severe disturbance scenario 3, the input voltage v _s Sustained drop is such that omega _n The transient response performance is slightly degraded with relatively little, but accurate voltage regulation can still be realized.

2) Steady state response analysis: when v _o Stable atNearby, load P _o Equivalent resistances of=10kw, 50kw, and 100deg.kw are 16Ω, 3.2Ω, and 1.6Ω, respectively, natural oscillation frequency ω _n 12566rad/s, 12568rad/s and 12574rad/s, respectively. Open loop transfer function G _o Bode diagram of(s), shown in FIG. 8, wherein G _o1 (s)、G _o2 (s) and G _o3 (s) G under the control of adaptive damping ratio for three loads respectively _o (s)；G' _o1 (s)、G' _o2 (s) and G' _o3 (s) is G without adaptive damping ratio control _o (s) initial damping ratios are respectively: ζ=0.0025, ζ=0.0125 and ζ=0.0249.

G 'when no self-adaptive damping ratio control is carried out' _o1 (s)、G' _o2 (s) and G' _o3 (s) has a higher open-loop cut-off frequency, corresponding to the set f _c =2khz. However, the fast response of an underdamped system implies overshoot and oscillations in the time domain; in the self-adaptive damping ratio control, the damping ratio is controlled by K _vp Dynamically adjusting damping ratio to ζ ^* The phase stability margin of the system increases, with accurate voltage regulation characteristics, =1. Load P at t=0.2 s _o From 10kW step to 50kW, the output voltages during transient and steady state are shown in FIG. 9, during transient when the ideal damping ratio ζ ^* =0.5, the output voltage of the underdamped system is restored toOvershoot oscillation occurs at the time; when the ideal damping ratio ζ ^* =1.0, the output voltage achieves fast smooth regulation; when the ideal damping ratio ζ ^* =1.5, the response adjustment time of the overdamping system becomes long. In steady state, the gain is controlled by the open loop gain G _K ＝ω _n As can be seen from the comparison of +2ζ, the open loop gain decreases with increasing damping ratio, and the static error Deltav of the output voltage _e With a concomitant increase. Damping ratio is made of ζ ^* Raise =0.5 to ζ ^* =1.0 and ζ ^* ＝1.5，Δv _e Increasing from 0.15V to 0.30V and 0.50V. Thus ζ ^* =1.0 can compromise both transient and steady state response performance.

Responsivity of parallel convertersThe energy can be: the hardware-in-the-loop system shown in FIG. 10 is constructed by a semi-physical simulation platform RT-LAB and an Xilinx FPGA ZYNQ7020 controller. The AN706 board card is a sampling module of the controller and is connected to the RT-LAB AO board card to realize input sampling; the AN9767 board card generates control signals of the gate devices, and the control signals are fed back to the converter model through the RT-LAB DI board card. And verifying transient response performance through different power abrupt changes of the pulse power load aiming at the parallel converter power supply structure. Transient response of the converter at various power abrupt changes is shown in FIG. 11, P _o From 10kW step to 80kW and 100kW, the output voltage drop amount Deltav _od -20.78V and-40.77V, respectively; the output voltage can be quickly and smoothly restoredRecovery time t _r 1.90ms and 2.35ms respectively.

The parameter differences and induced resistances of the parallel converters result in an imbalance in the output current. When the controller is provided with additional current sharing control, the parallel output current can maintain a good current sharing effect, as shown in fig. 12 (a); when current sharing control is not considered, there is a large deviation in parallel output current, and as shown in fig. 12 (b), the deviation of output current gradually increases with time, and the overall reliability of the inverter that takes over excessive output current for a long period of time is reduced due to heat generation.

To verify the control effect of the different initial conditions, a response test was performed by loading successive power steps. The power of the pulse power load is continuously stepped from 50kW to 200kW, the transient response of the converter is shown in FIG. 13, the single step power of the load is 50kW, and the output voltage drops by Deltav _od about-15.0V and-14.0V, the converter is capable of achieving fast smooth voltage regulation; the parallel output current deviation is smaller under different load powers, so that a good current balancing effect is ensured.

Compared with the prior art, the method and the device firstly convert the control problem of uncertain load disturbance into the damping ratio control problem, so that the transient response performance of the output voltage can be directly and accurately regulated through the damping ratio, and the method and the device have applicability to uncertain variable loads and have no parameter dependence; meanwhile, nonlinear saturation of duty ratio is utilized in the control process, so that the output voltage is ensured to have larger natural oscillation frequency when approaching to the reference value, and the capability of the control method for inhibiting input voltage disturbance is improved; finally, the control method effectively suppresses disturbance of the output voltage in the steady-state process and reduces static errors through the design of the open-loop cut-off frequency and the open-loop gain.

The foregoing embodiments may be partially modified in numerous ways by those skilled in the art without departing from the principles and spirit of the invention, the scope of which is defined in the claims and not by the foregoing embodiments, and all such implementations are within the scope of the invention.

Claims (8)

1. The self-adaptive damping ratio control method for the ship pulse power load Buck converter is characterized by comprising the following steps of:

step 1), a single-input single-output closed-loop control system of a parallel Buck converter is established, and an initial damping ratio and a natural oscillation frequency are obtained;

step 2) performing transient response design, realizing self-adaptive damping ratio adjustment through control parameter design, adjusting the initial damping ratio to an ideal damping ratio, and analyzing the influence of an initial value of output voltage on transient response;

step 3) steady-state response design is carried out, the upper limit of the value of the control parameter is limited through open-loop cut-off frequency design, and the optimal duty ratio for realizing output voltage regulation is obtained;

step 4) verifying control stability according to the control parameter values obtained in the step 2 and the step 3;

and 5) carrying out additional adjustment on the optimized duty ratio obtained in the step 3) to obtain a final duty ratio which simultaneously considers voltage adjustment and current sharing control, and realizing current sharing control of the parallel converter.

2. The adaptive damping ratio control method of the ship pulse power load Buck converter according to claim 1, wherein the dynamic process of the parallel Buck converter is as follows:wherein: v _s And v _o I is the input voltage and the output voltage of the ith converter _Li And i _oi The inductor current and the output current of the ith converter; s is(s) _i Is a control signal of a gate device, and has a corresponding duty ratio d _i ；L _i And C _i Is the branch inductance and the output capacitance, R _i Representing the equivalent resistance of the output end, connecting m Buck converters in parallel, and obtaining +.>Wherein: r is the total equivalent resistance of the output end, +.>

Voltage outer loop through v _o With reference value ofDeviation e of (2) _v (t) generating an inductor current reference value +.>The current inner loop passes through the current deviation e _i (t) generating a PWM signal, deriving a voltage-like loop by deriving the voltage loop, the output of the voltage-like loop being made of +.>To its derivative->V in dynamic process for parallel Buck converter _o Second order derivative and substitute +.>Obtaining a transformed second-order system;

said transformedOutput terminal uncertainty load R of second-order system _i The processing of the output load is as follows, except that a specific type is difficult to predict accurately: r in one or several control periods _i Held constant and defined by R _i ＝v _o /i _oi Obtained by combining the actual load with R _i Is considered as a disturbance term epsilon in response to the output voltage _v Suppressing the attenuation of a high frequency band by a control method;

deriving a voltage-like loop representation of a transformed second-order systemI.e. K is present _vi And K _vp Can be->Conversion to and v _o And->Related controlled sources and time domain representation of the ith converter output voltage

V due to parallel converters _s And v _o In order to ensure the inductance voltageThe variation ranges are the same, and each converter obtains the same K _vi And K _vp Thus, the time domain expression of the parallel converter output voltage +.>

By voltage-like loop conversion, a second-order equation of the output voltage and a reference value thereof is established, the time-varying input voltage is eliminated, and the nonlinear saturation of the duty cycle is mapped to K _vi And K _vp Is a range of values.

3. The adaptive damping ratio control method of a ship pulse power load Buck converter according to claim 1 or 2, wherein the single-input single-output closed-loop control system established in step 1 satisfies: dynamic characteristics of the system are defined byDetermining, wherein: ζ is damping ratio, ω _n Is natural oscillation frequency omega _n With K _vi Increasing and increasing, the same damping ratio has faster dynamic response; zeta with K _vi Increasing and decreasing, the response increases the likelihood of overshoot oscillations.

4. The method for controlling the adaptive damping ratio of the ship pulse power load Buck converter according to claim 1, wherein the step 2 specifically includes:

2.1 Adaptive adjustment of damping ratio): for single inputSingle output (v) _o ) Second order system, zeta<Under-damping of the system in the 1 time, and input amplitude is +.>Overshoot and ringing may occur in the step response of (a); when zeta is>1, the system is over-damped, and the response adjustment time is increased along with the increase of the damping ratio; when ζ=1, the system is in critical damping, a fast smooth step response can be achieved, constant K for an indeterminate varying load _vi And K _vp The underdamping or the overdamping of the system can not ensure that the output voltage of the transient process is quickly and smoothly adjusted to the reference value, on the other hand, K _vp Essentially represented by differential negative feedback control of the system without changing the natural oscillation frequency omega _n Dynamic adjustment of damping ratio can be realized by K _vi And K _vp Can adjust ζ to ideal damping ratio ζ ^* =1, implementing adaptive damping ratio control;

2.2 Control parameter design refers to: open loop gain G of system _K ＝ω _n 2 zeta with K _vi Increase and increase at K _vp Maximum value is obtained when=0, and K is increased _vi The response performance is improved, and the static error is reduced; will K _vi Initializing to maximum to obtain high open loop gain with an initial damping ratio ζ ₀ ＝1/(2RCω _n ) The method comprises the steps of carrying out a first treatment on the surface of the To set the initial damping ratio ζ ₀ Adjusted to the ideal damping ratio ζ ^* ＝1，K _vp The value of (2) isWhen zeta is ₀ ≥ζ ^* Without introducing differential negative feedback control K _vp At this time, the damping ratio has no downward adjustment range; if ζ ₀ ＜ζ ^* Through K _vp Adjusting damping ratio to ζ ^* ；

2.3 Effect of initial value of output voltage on transient response): the initial state of the transient process output voltage is not zero, the influence of the initial state on transient response needs to be analyzed, and when the damping ratio of the system is higher than the threshold value by K _vi And K _vp Adjusted to the ideal damping ratio ζ ^* When=1, the transient response is analyzed by the time domain to obtain the time domain solutionWherein: the variable band (t) represents the value at time t, t _n Time of nth control period, v _o (t ₀ ) And->V at the initial zero time respectively _o And->Omega thanks to non-linear saturation of duty cycle _n With v _o Approach->Increasing for dynamically increasing ω _n The initial state of the output voltage does not cause overshoot oscillation of the transient response of the second-order system, which effectively inhibits the influence of the initial state of the output voltage on the transient response, and the inhibition capability follows v _o Approach->And the lifting is continuous.

5. The adaptive damping ratio control method of a marine pulse power load Buck converter as claimed in claim 4, wherein whenShould satisfy->To increase the inductance current i _Li And then through the current difference i _Li -i _oi Increasing v for capacitor charging _o ，/>The maximum value of (d) appearing at d _i =1; if->Should satisfy->To reduce the inductance current i _Li ，/>The minimum of (d) occurs at d _i =0; mapping non-linear saturation of duty cycle to K _vi The value range of (2) satisfies:wherein: k (K) _max For open loop cut-off frequency limitLower K _vi Upper limit of the value of (2); min (·) is the minimum operator, i.e. guarantee K _vi Always receive K _max Is a constraint of (2); epsilon is a minimum close to 0 to avoid the presence of K in the damping ratio expression _vi ＝0；

When K is _vi When the maximum value is taken, for the same input voltage, when v _o Approach toK _vi Is limited by K _max The method comprises the steps of carrying out a first treatment on the surface of the Conversely, K _vi Nonlinear saturation limited by duty cycle;

in order to suppress the influence of input voltage disturbance, ω should be ensured _n At v _o Approach toGradually increasing, defining the current time as the j-th control period when +.>When K is _vi The upper limit of the value of (a) is not limited by v _s Is a function of (1); when->When, in order to obtain omega _n (t _j )≥ω _n (t _j-1 )，Δv _s (t _j ) Should satisfy->Wherein: deltav _o (t _j ) And Deltav _s (t _j ) The j-1 th to j-th control periods v _o And v _s The variation of (a), i.e. Deltav in a single control period _o (t _j ) Exchangeable for Deltav _s (t _j ) Is allowed to disturb such that ω _n (t _j )≥ω _n (t _j-1 ) Still can meet the requirements.

6. The method for controlling the adaptive damping ratio of the ship pulse power load Buck converter according to claim 1, wherein the step 3 specifically includes:

3.1 Open loop cut-off frequency design R, K at system steady state _vi And K _vp Constant, single-input single-output closed loop system for obtaining output voltage and reference value thereof through s-domain transformation as shown in figure 6, closed loop transfer functionThe static error of the system decreases as the open loop gain increases, but excessive open loop gain may cause the system to destabilize; meanwhile, as the modeling of the converter adopts an average model, the control method should consider the design of open-loop cut-off frequency, and define the open-loop cut-off angle frequency as omega _c Open loop transfer function->At s=jω _c Amplitude of the region->Defining the control frequency of the converter as f _s And will open loop cut-off frequency f _c Limited to af _s (generally ensure a)<1/3, e.g. taking a=1/10 to 1/5), taking into account the open loop cut-off frequency limit +.>

3.2 Optimum duty cycle for voltage regulation by K) _max Limit K _vi Is substituted into K _vi 、K _vp Andto->Obtaining an optimized duty cycle of the ith converter

7. The method for controlling the adaptive damping ratio of the ship pulse power load Buck converter according to claim 1, wherein the step 4 specifically includes: selecting a state vectorInput vector->Establishing a state space equation of a parallel converter>Wherein: />A and B are respectively a state matrix and an input matrix, and the characteristic root of the matrix A is +.>The characteristic roots of matrix A should all have negative real parts, i.e. guarantee K, according to stability conditions _vi >0 and K _vp >L/R, respectively, the damping ratio should satisfy ζ>0 due to the presence of K _vi >0 and K _vp 0. Gtoreq.therefore, K _vi And K _vp The control stability of the parallel converter is ensured, and the stability is not influenced by the inductance and capacitance values of the converter and the perturbation of parameters.

8. The method for controlling the adaptive damping ratio of the ship pulse power load Buck converter according to claim 1, wherein the step 5 specifically includes: the output current of the Buck converter, which can be considered to be provided by the inductor current dc component, is fed into the output capacitor loop, so that current sharing control can be achieved by varying the inductor current through additional adjustment of the duty cycle, actual operation typically employs discrete control,inductor current of the ith converter during the (n+1) th control periodt _n+1 Average inductor current of time-of-day parallel convertersTo reduce t _n+1 Unbalanced output current at time when K _vi And K _vp Can be determined by maintainingIs balanced, additional current regulation is achieved and the influence on the voltage regulation is avoided, i.e. guaranteed +.>If->By Δd _i (t _n )>0 increasing the inductor current; otherwise, guarantee Δd _i (t _n )<0, when considering current sharing control, the duty ratio is finally corrected to d' _i (t _n )＝d _i (t _n )+Δd _i (t _n ) Wherein: />If d' _i (t _n ) Duty cycle saturation occurs and Δd should be reduced in equal proportion _i (t _n )。