Pulse load power stabilizing method based on power self-adaption-passive control

Abstract

The invention discloses a pulse load power stabilizing method based on power self-adaption-passive control, belongs to the technical field of ship comprehensive power system stability control, and solves the problem of oscillation instability of a diesel engine set caused by mismatching between the power gradeability of the diesel engine set and pulse load power abrupt change. The method is based on a multi-interleaving Boost circuit, passive control with virtual damping and interconnection matrix injection is adopted, and a direct-current power supply circuit has large-range asymptotic stability through an Euler-Lagrange model, an energy function and a Lyapunov criterion; and then designing a power reference value adaptive strategy, adaptively matching a pulse load working condition, limiting front-end power fluctuation and a change rate to adapt to a diesel engine set, and realizing front-end power impact stabilization under all working conditions.

Description

Technical Field

[0001] This invention relates to the field of stability control technology for integrated shipboard power systems, and in particular to a pulse load power smoothing method based on power adaptive-passive control. Background Technology

[0002] As China's development increasingly focuses on the deep blue sea, the demand for specialized equipment with pulse loads in shipbuilding is growing rapidly. This places higher demands on the design of modern ship electrical systems. Pulse loads, typically based on power electronic control, are characterized by high power, high peak values, strong impact, and wide bandwidth. Ship integrated electrical systems usually use diesel engines in parallel as the energy source, resulting in relatively weak system inertia. Furthermore, existing ship integrated electrical systems are primarily designed for electric propulsion systems and are not adapted to pulse loads. Therefore, when a pulse load is connected, it can impact the ship's electrical system, potentially causing the ship's generators to disconnect from the grid and shut down. Thus, research is needed on strategies to mitigate the power impact of pulse loads in ship integrated electrical systems. Summary of the Invention

[0003] This invention proposes a pulse load power smoothing method based on power adaptive-passive control. By using passive theory, the control law of the DC power supply circuit is designed with the help of the Euler-Lagrange standard form and Lyapunov qualitative criterion. On this basis, by analyzing the relationship between the power change rate and the back-end voltage, and combining the power reference value adaptive setting rule on the basis of passive control, the adaptive adjustment of power impact is completed. This solves the problem of oscillation and instability of diesel generator sets caused by the mismatch between the power ramping capability and the sudden power change of pulse load in the prior art.

[0004] A pulse load power smoothing method based on power adaptive-passive control includes the following steps: S1. Analyze the working state of the DC power supply system with pulse load, write the corresponding state equations, and use the spatial state averaging method to weighted average the state equations to obtain the average model of the Boost circuit of the DC power supply system with pulse load. S2. Extend the average model to a multi-interleaved parallel power supply circuit, verify the passivity of the extended circuit, and organize the extended average model into a standard Euler-Lagrange (EL) form based on the interconnection and damping distribution method. Select the energy of the capacitor and inductor in the circuit as the energy function, and derive the duty cycle calculation function of the switching device by combining the Lyapunov stability criterion. S3. Investigate the relationship between the front-end power change rate and the back-end pulse load voltage of the multi-interleaved parallel power supply circuit. Based on the relationship, design an adaptive power reference value control strategy to ensure that the DC power supply system limits the front-end power change rate to match the power ramp-up capability of the diesel generator set while ensuring that the pulse load voltage is within the allowable fluctuation range.

[0005] Furthermore, in S1, the operating state of the DC power supply system is four different combinations of the switching state of the Boost circuit transistor, and the corresponding state equations are as follows: (1) (2) (3) (4) In the formula, For inductor current, The voltage across the capacitor. This refers to the inductance value of the Boost circuit. The equivalent series resistance of the inductance. This is the value of the filter capacitor. The equivalent resistance of the pulse load is . This is the DC bus voltage. The average model is obtained by applying a spatial state averaging method to formulas (1)-(4). The expression of the average model is as follows: (5) In the formula, This refers to the duty cycle of the switching transistor in the Boost circuit. Pulse load terminal voltage, This refers to the output-side filter capacitor value. This is the equivalent resistance of the pulse load.

[0006] Furthermore, in S2, the process of verifying the passivity of the extended circuit includes: The spatial state equation of a multi-input multi-output system is defined as follows: (6) In the formula, For system state variables, For the derivative of the state variable, Let y be the system input and y be the system output; if a positive definite energy function exists... Make: (7) Then the system relative to the supply rate It is dissipative, when for uT y At this time, the system is passive; the energy stored in the inductors and capacitors in the extended circuit is selected as the positive definite energy function. The expression is: (8) According to the law of conservation of energy, the extended circuit in t The total energy at time t is: (9) In the formula, for t Total energy of the system at any given moment The initial energy of the system, For pulse load power, For inductor and resistor power; if selected u T y = U bus i L Then we have: (10) Combining equations (7) and (10), it is determined that the extended circuit is a strictly passive system.

[0007] Furthermore, in S2, the process of rearranging the extended average model into the standard Eulerian-Lagrange form includes: The extended average model of the multiple interleaved parallel power supply circuit is obtained by applying the spatial state averaging method: (11) Equation (11) is rearranged into a standard Euler-Lagrange model, the expression of which is: (12) In the formula, J is the system interconnection matrix, and has Simultaneously satisfy This affects the proportion of voltage changes at the pulse load terminal. R Let be the system damping matrix, and have Its influence on the proportion of changes in inductor current.

[0008] Furthermore, in S2, the derivation of the duty cycle calculation function for the switching device also includes the process of defining the energy error function and injecting virtual damping: The energy error function is defined as follows: (13) If equation (13) converges to zero, the corresponding state variable deviation will also converge to zero. To accelerate the convergence speed, virtual damping and virtual interconnection matrix are injected into equation (12), resulting in: (14) Differentiating the error energy function and substituting equation (13) into it, we get: (15) In the formula, R d = R + R a According to the Lyapunov stability criterion, for the system to be asymptotically stable, there needs to exist an antiderivative that is positive definite and whose derivative is negative definite. Based on the above analysis, the system energy error function is selected as the positive definite Lyapunov function. Therefore, it is only necessary to design the control law to make equation (15) negative definite. R d It is a diagonal matrix, and its internal elements are non-negative, therefore Since it is a quadratic form and its value is positive, in order to ensure that the system energy error function is negative definite, the part in parentheses in equation (15) is selected as zero, and the control law is selected as follows: (16) Further rewriting equation (15) as: (17) Therefore, under the control law of equation (16), the following condition is satisfied. Meanwhile, its derivative According to the Lyapunov stability criterion, the power supply circuit has global asymptotic stability at this time; When the power supply circuit operates at a certain static point, its state variable reference value remains constant, and its derivative value is zero. Therefore, equation (16) simplifies to: (18).

[0009] Furthermore, in S2, substituting the relevant variables from equation (18) into equation (16), the duty cycle calculation function for each switching device in the DC power supply circuit is obtained. The expression for the duty cycle calculation function is: (19) In the formula, , ,and These are the inductor currents of the 1st, 2nd, and nth paths, respectively. This is the DC bus voltage. This is the voltage at the pulse load terminal. , , For damping matrix elements, , , For interconnected matrix elements, as well as These are the reference values ​​for inductor current and pulse load terminal voltage, respectively. , , The duty cycle of the corresponding switching transistor Furthermore, in S3, when investigating the relationship between the front-end power change rate and the back-end voltage, the following conclusions were drawn: When the average power of the pulsed load is the same and the rate of power change decreases, the degree of voltage drop from the rated value at the back end increases as the rate of power change decreases. When a pulse load is applied, the voltage at the back end drops, and when it is unloaded, it rises; voltage fluctuations exist under both operating conditions. The time for a DC power supply to reach steady state is negatively correlated with the rate of change of power limited by the front end; that is, the greater the rate of change of power, the shorter the steady state time. When the power change rate is zero, the power supply and demand at the front and back ends of the system are balanced, and the voltage at the pulse load end fluctuates within a fixed range.

[0010] Furthermore, in S3, the adaptive power reference value setting rule adjusts the front-end power change rate according to the magnitude of the back-end voltage deviation from the rated voltage: the greater the magnitude of the voltage deviation from the rated value, the greater the power adjustment magnitude per unit time, and ensures that the change rate of the front-end input power within one cycle does not exceed the maximum power change rate that the diesel generator set can accept.

[0011] A storage medium storing a computer program that, when executed by a processor, implements the above-described pulse load power smoothing method based on power adaptive-passive control.

[0012] A computer device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described pulse load power smoothing method based on power adaptive-passive control.

[0013] The beneficial effects of this invention are as follows: The pulse load power smoothing method based on power adaptive-passive control proposed in this invention can ensure the DC power supply system has a wide range of asymptotic stability, ensuring that the pulse load can operate stably under different operating conditions. When the pulse load is under a single operating condition, sudden addition or removal, multiple operating conditions superimposed, or operating condition switching, compared with traditional control strategies, the control strategy proposed in this invention can significantly reduce the average power fluctuation on the diesel engine side while ensuring that the voltage at the pulse load end is within the allowable range.

[0014] In summary, the control strategy proposed in this invention can significantly reduce the amplitude of front-end power fluctuations, limit the rate of change of front-end power, and ensure that the voltage at the pulse load end is within the rated operating range while reducing power fluctuations in steady state, thus solving the problem of power impact on diesel generator sets under all operating conditions of pulse loads. Attached Figure Description

[0015] Figure 1 Topology diagram of a ship's medium-voltage integrated power system; Figure 2 Model of a power supply circuit for a pulsed load; Figure 3 Status of the pulse load power supply circuit; Figure 4 It is a four-fold interleaved parallel power supply circuit; Figure 5 This is a schematic diagram of the power adaptive-passive control strategy of the present invention; Figure 6 This is a schematic diagram showing the relationship between the back-end voltage and the front-end power change rate after limiting the rate of change of the front-end input power. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Reference Figures 1-5 This embodiment uses a multiple DC power supply circuit as an example for illustration: Step 1: Derive the average model of the power supply circuit The average model of the DC power supply system is derived using the spatial state averaging method. Based on the four different combinations of switching states of the DC power supply circuit's switching transistors, we can obtain: (1) (2) (3) (4) Spatial state averaging of equations (1)-(4) yields: (5) Step 2: System Passive Verification Consider a multi-input multi-output system, its space state equation (6) In the formula, For system input, This is the system output. If a positive definite energy function exists... Make: (7) Then the system relative to the supply rate It is dissipative, when for u T y When the system is passive, and the zero state is detectable, its continuously differentiable storage function can be directly used as a positive definite Lyapunov function, and the system is necessarily stable.

[0018] For DC power supply circuits, the energy stored in their inductors and capacitors is selected as the energy function. H ( x ): (8) According to the law of conservation of energy, the entire system in t Total energy at any given moment: (9) In the formula, P For pulse load power, P R If the power of the inductor and resistor is selected u T y = U bus i L Then we have: (10) Combining equations (7) and (10), it can be seen that the DC power supply circuit is strictly passive. Therefore, a passive controller can be designed.

[0019] Step 3: Passive Controller Design Referring to equations (1) to (5), spatial state averaging of the multiple DC power supply circuits yields: (11) Equation (11) can be rearranged into the following standard EL model: (12) In the formula, J is the system interconnection matrix, and has At the same time satisfy This affects the expected proportion of voltage; R Let be the system damping matrix, and have This affects the proportion of change in inductor current. If the system is passive, then the system's state variables can be directly related to energy. To ensure that the inductor current and capacitor voltage converge to the desired values, an energy error function is defined: (13) If equation (13) converges to zero, then the corresponding state variable deviation will also converge to zero. To accelerate the convergence speed, virtual damping and a virtual interconnection matrix are injected into equation (12), resulting in: (14) Differentiating the error energy function and substituting equation (13) into it, we get: (15) In the formula, R d = R + R a According to the Lyapunov stability criterion, for the system to be asymptotically stable, there needs to exist an antiderivative that is positive definite and whose derivative is negative definite. Based on the above analysis, the system energy error function is selected as the positive definite Lyapunov function, so it is only necessary to design the control law to make equation (15) negative definite. Since R d It is a diagonal matrix, and its internal elements are non-negative, therefore Since it is a quadratic form and its value is positive, in order to ensure that the system energy error function is negative definite, the part in parentheses in equation (15) can be selected as zero, and the control law is selected as follows: (16) Further rewriting equation (15) as: (17) Therefore, under the control law of equation (16), the following condition is satisfied. Meanwhile, its derivative According to the Lyapunov stability criterion, the power supply circuit has global asymptotic stability at this time.

[0020] When the power supply circuit operates at a certain static point, its state variable reference value remains constant, and its derivative value is zero. Therefore, equation (16) can be simplified to: (18) Substituting the relevant variables in equation (18) into equation (16), the duty cycle calculation function for each switching device in the DC power supply circuit is obtained as follows: (19) Step 4: Design of Power Adaptive Control Strategy When the rate of change of the front-end input power is limited, the relationship between the back-end voltage and the rate of change of the front-end power is as follows: Figure 6 As shown, From Case 1 to Case 3, the average power of the pulsed load is the same, but the rate of power change decreases sequentially. For Case 1 and Case 3 respectively... t Loaded at time 0, and t d1 and t d3 Uninstall at any time; Case 2, on the other hand, is... t Uninstall at 0 o'clock, and t u2 Reload is required at all times. Case 4 simulates multiple operating conditions superimposed, with a power change rate of Δ. P p4 ,exist t The average power applied at time 0 is P p1 The operating condition is described, and after reaching stability, another operating condition is superimposed to make the average power reach a certain level in steady state. P p2 .

[0021] Comparing Case 1 and Case 3, when the power change rate is limited, the downstream voltage will drop from its rated value, and the smaller the power change rate, the more severe the drop. Comparing Case 2 and Case 3, it can be seen that regardless of whether the pulse load is in a loaded or unloaded state, the downstream voltage will fluctuate; however, under loading, this manifests as a voltage drop, while under unloading, it manifests as a voltage rise. Comparing Case 1 and Case 4, it can be seen that the steady-state time of the DC power supply is negatively correlated with the power change rate limited by the front end; that is, the larger the power change rate, the shorter the time required to reach steady state. In these cases, when the power change rate is zero, the power supply and demand relationship between the front and back ends of the system is balanced, and the voltage at the pulse load end will fluctuate within a fixed range. Based on the above analysis of the coupling relationship between the downstream voltage and the front-end power, the voltage fluctuation range is designed so that different power change rates are regulated when the voltage is in different ranges, and the greater the voltage deviation from the rated voltage, the greater the power adjustment amplitude per unit time. Adaptive Power The given rules are as follows: (20) The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method of power adaptive-passive controlled pulse load power flattening, characterized in that, The method comprises the following steps: S1, analyzing the working state of a direct current power supply system carrying a pulse load, writing corresponding state equations, and using a space state average method to weight average the state equations to obtain an average model of a Boost circuit of the direct current power supply system carrying the pulse load; S2, expanding the average model to a multiple interleaved parallel power supply circuit, verifying passivity of the expanded circuit, arranging the expanded average model into a standard Euler-Lagrange form based on an interconnection and damping distribution method, selecting energy of capacitors and inductors in the circuit as an energy function, and deducing a duty cycle calculation function of a switching device in combination with Lyapunov stability criterion; S3, exploring a relationship between a front-end power change rate of the multiple interleaved parallel power supply circuit and a rear-end pulse load end voltage, and designing a power reference value adaptive given control strategy based on the relationship, so that the direct current power supply system ensures that the pulse load end voltage is in an allowable fluctuation range while limiting the front-end power change rate to match a power climbing ability of a diesel engine group.

2. The power adaptive-passive control based impulse load power ride-through method of claim 1, wherein, In S1, the working state of the direct current power supply system is four different combination states of a switching tube of a Boost circuit, and corresponding state equations written are: (1) (2) (3) (4) wherein is the inductance current, is the capacitance voltage, is the inductance value of the Boost circuit, is the inductance equivalent series resistance, is the filter capacitance value, is the equivalent resistance of the pulsed load, is the DC bus voltage, The space state average method is used to weight average formulas (1)-(4) to obtain the average model, and an expression of the average model is: （5） In the formula, a duty cycle of a switch tube of the Boost circuit, a voltage at a pulse load end, an output-side filter capacitance value, an equivalent resistance of the pulse load.

3. The power adaptive-passive control based impulse load power ride-through method of claim 2, wherein, In S2, a process of verifying passivity of the expanded circuit comprises: A space state equation of a multiple input multiple output system is defined as: （6） where is a system state variable, is a state variable derivative, is a system input, y is a system output; if there exists a positive definite energy function such that: （7） The system is dissipative with respect to the supply rate when is positive u T y The system is passive when The positive definite energy function is chosen as the energy stored in the inductor and capacitor in the extended circuit （8） According to the law of conservation of energy, the total energy of the extended circuit at t the time instant is: （9） wherein is t the total system energy at time is the initial system energy, is the pulse load power, is the inductance resistance power; if u T y = U bus i L then: （10） In combination with formulas (7) and (10), it is determined that the expanded circuit is a strictly passive system.

4. The power adaptive-passive control based impulse load power ride-through method of claim 3, wherein, In S2, a process of arranging the expanded average model into a standard Euler-Lagrange form comprises: The space state average method is used to the multiple interleaved parallel power supply circuit to obtain the expanded average model as: （11） Formula (11) is arranged into a standard Euler-Lagrange model, and an expression of the standard Euler-Lagrange model is: （12） In the formula, J is the system interconnection matrix, and has At the same time, meet The proportion of the change of the voltage at the pulse load end is affected, R is the system damping matrix, and has The proportion of the change of the inductance current is affected.

5. The power adaptive-passive control based impulse load power ride-through method of claim 4, wherein, In S2, when deducing the duty cycle calculation function of the switching device, a process further comprises defining an energy error function and injecting a virtual damping: The energy error function is defined as: （13） If formula (13) converges to zero, corresponding state variable deviations also converge to zero, in order to accelerate the convergence speed, a virtual damping and injection of a virtual interconnection matrix are performed on formula (12), and thus formula (12) is obtained: （14） A derivative of the error energy function is obtained, and formula (13) is substituted into formula (12) to obtain: （15） where, R d R R a According to Lyapunov stability criterion, if we want to make the system asymptotically stable, we need to exist a positive definite function, whose derivative is negative definite. According to the above analysis, we choose the system energy error function as the positive definite Lyapunov function, so we only need to design the control law to make formula (15) negative definite. Since R d is a diagonal matrix, and the internal elements are non-negative, so is a quadratic form, whose value is positive. Therefore, in order to ensure that the system energy error function is negative, we choose the bracket part of formula (15) to be zero, and the control law is as follows:​​ （16） Formula (15) is further rewritten as: （17） Thus, under the control of the rate of formula (16) to meet At the same time, its derivative According to Lyapunov stability criterion, the power supply circuit has global asymptotic stability at this time; When the power supply circuit works at a certain static point, a state variable reference value remains constant, and a derivative value is zero, and thus formula (16) is simplified as: （18）。 6. The power adaptive-passive control based impulse load power ride-through method of claim 5, wherein, In S2, relevant variables in formula (18) are substituted into formula (16) to obtain a duty cycle calculation function of each switching device of the direct current power supply circuit, and an expression of the duty cycle calculation function is: （19） wherein, , , and are the 1st, 2nd, and nth leg inductor currents, respectively, is the DC bus voltage, is the pulse load terminal voltage, , , are the damping matrix elements, , , are the interconnection matrix elements, and are the reference values for the inductor currents and the pulse load terminal voltage, respectively, , , are the duty cycles for the corresponding switching tubes.

7. The power adaptive-passive control based impulse load power ride-through method of claim 6, wherein, In S3, when exploring the relationship between the front-end power change rate and the rear-end voltage, the following conclusions are included: When average powers of the pulse loads are the same and the power change rate decreases, a degree of a rear-end voltage drop from a rated value intensifies with the decrease of the power change rate; The rear-end voltage shows a drop when the pulse load is loaded and shows a rise when the pulse load is unloaded, and voltage fluctuations exist in both working conditions; The time for the DC power supply to reach steady state is negatively related to the power change rate limited by the front end, i.e. the greater the power change rate, the shorter the steady state time; When the power change rate is zero, the power supply and demand of the system front and back end is balanced, and the voltage at the pulse load end fluctuates within a fixed range.

8. The power adaptive-passive control based impulse load power ride-through method of claim 7, wherein, In S3, the power reference value is adjusted according to the amplitude of the deviation of the back end voltage from the rated voltage according to a given rule: the greater the amplitude of the voltage deviation from the rated value, the greater the adjustment amplitude of the power in a unit of time, and the change rate of the front end input power in a cycle does not exceed the maximum power change rate acceptable by the diesel generator set.

9. A storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the pulse load power smoothing method based on power adaptive-passive control according to any one of claims 1-8.

10. A computer device, comprising: Comprise: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the pulse load power smoothing method based on power adaptive-passive control according to any one of claims 1-8.

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