Nonlinear variable structure observation robust control device and control method of multi-source power supply system

Abstract

The present application relates to the technical field of multi-distributed power supply system control, and particularly relates to a nonlinear variable structure observer robust control device and control method for a multi-source power supply system.The present application comprises a plurality of distributed power sources, a power converter, a common bus, a current sensor, a voltage sensor, a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller.The power distribution controller adopts a voltage and current deviation longitudinal intercept double compensation algorithm based on proportional integral differential control of average voltage and current.The voltage controller adopts a nonsingular exponential voltage variable structure control algorithm.The current controller adopts a nonsingular exponential current variable structure control algorithm.The present application provides accurate parameters for the distributed controller, helps the system to resist noise and uncertain interference, and improves the performance of the system and the robustness of the bus voltage.

Description

Technical Field

[0001] This invention relates to the field of control technology for multi-distributed power supply systems, and particularly to a robust control device and method for nonlinear variable structure observation of multi-source power supply systems. Background Technology

[0002] The fundamental control objective of a multi-source power supply system is to maintain a stable DC bus voltage and balance the energy of each distributed power source. Low-level control is the foundation of energy management and the key to reliable operation of such systems. Multi-source power supply systems consist of numerous power electronic converters with low inertia, making them susceptible to significant voltage fluctuations due to disturbances. Traditional droop control methods in multi-source systems suffer from uneven shunt ratios, leading to local power source overload and partial power source idleness, resulting in excessive bus voltage deviation. The accuracy of voltage and current sensors in distributed power units within a multi-source power supply system is crucial for its reliable operation; however, sensors in measuring equipment degrade over time, potentially causing measurement errors. Therefore, it is essential to design highly adaptable observers for multi-source power supply systems. These observers not only provide accurate measurement parameters but also help the system resist noise and uncertain interference, eliminate the adverse effects of erroneous measurements, and ensure the normal operation of the system. When the power supply system is subjected to external disturbances or load power fluctuations, the tracking performance and convergence speed of traditional control methods in the current and voltage control loops are poor, easily causing large fluctuations in the bus voltage. Therefore, it is necessary to design voltage and current loop controllers with good comprehensive performance based on the characteristics of multi-source power supply systems, so as to improve the control performance and robustness of multi-source power supply systems. Summary of the Invention

[0003] To address the above problems, this invention discloses a robust control device and method for nonlinear variable structure observation in multi-source power supply systems.

[0004] The technical solution of this invention is as follows: a robust control device for nonlinear variable structure observation in a multi-source power supply system, comprising multiple distributed power sources, a power converter, a common bus, a current sensor, a voltage sensor, a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller; the output of the nonlinear variable structure observer is connected to the input of the power distributor; the output of the power distributor is connected to the input of the voltage controller; the output of the voltage controller is connected to the input of the current controller; the output of the current controller is connected to the input of the power converter's switching transistor; the distributed power sources are connected to the common bus through the power converter.

[0005] As a preferred embodiment of the present invention, the multiple distributed power sources are connected to a common bus via a power converter, and the power converter control loop consists of a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller.

[0006] A control method for a robust control device for a nonlinear variable structure observation of a multi-source power supply system is provided. The power distribution controller adopts a dual compensation algorithm for voltage and current deviation based on proportional-integral-derivative control of average voltage and current. The voltage controller adopts a non-singular exponential voltage variable structure control algorithm. The current controller adopts a non-singular exponential current variable structure control algorithm.

[0007] As a preferred technical solution of the present invention, the design of the nonlinear variable structure observer includes the following steps:

[0008] S11. Considering only the converter output voltage, the state-space model of the j-th distributed power source is obtained as follows:

[0009]

[0010] y j (t)=C j x j (t)=V dcj

[0011] Wherein, the state variable x is taken j =[V dcj i Lj ] T V dcj Let i be the output voltage of the j-th power converter. Lj Let A be the terminal current of the j-th distributed power source, where j = 1, 2, ..., n. j B is the coefficient matrix of the state variables. j For the control variable coefficient matrix, C j To output the coefficient matrix of the variables, D j Let A be the coefficient matrix of the system's uncertainty terms. j ∈R n×n B j ∈R n×p C j ∈R q×n , and D j ∈R n×k Where n>p≥q>k, assume matrix C j Full rank, function ξ j ||ξ represents the uncertainty in the j-th distributed power source. i (t,y,u)||<β, where β is a positive scalar;

[0012] S12. Based on the state-space model of the j-th distributed source, design the following nonlinear variable structure observer:

[0013]

[0014] The estimated output of the j-th distributed power system is:

[0015]

[0016] In the formula, V represents the state variable of the augmented system. dc and i Lj The estimate of v, and v j It is a nonlinear switching term with the following definition:

[0017]

[0018] Indicates the output estimation error; γ j It is a positive calibrator, γ j ∈R + Q 0j Q is the initial gain matrix of the nonlinear variable structure observer. 0j Symmetric and positive definite, Q 0j ∈R n×n ;

[0019] S13. Obtain the positive definite gain matrix Q of the nonlinear variable structure observer. j , making Among them, H j It conforms to the following linear matrix inequalities:

[0020]

[0021] in, D j It is a constant matrix, I j It is the identity matrix, α 0j The value of Q depends on j Properties of linear matrix inequalities;

[0022] S14. Design the gain matrix R of a nonlinear variable structure observer. qj R pj and Q j as follows:

[0023] R qj =α 0j Q j -1 C j T (D j D jT ) -1

[0024]

[0025]

[0026] in,

[0027] S15. Obtain the state variable estimation error of the nonlinear variable structure observer. Its dynamic characteristics are as follows:

[0028]

[0029] As a preferred embodiment of the present invention, the power distribution controller employs a dual compensation algorithm for the longitudinal intercept of voltage and current deviation based on proportional-integral-derivative control of average voltage and current, comprising the following steps:

[0030] S21, The output current i of the power converter is obtained by the current sensor and the voltage sensor respectively. dcj and output voltage V dcj ;

[0031] S22, based on the output current i of the j-th distributed power unit converter dcj and output voltage V dcj Calculate the average output current and voltage of the power unit converter respectively:

[0032]

[0033]

[0034] S23. The following is a dual compensation algorithm for the longitudinal intercept of voltage and current deviation based on proportional-integral-derivative control of average voltage and current:

[0035]

[0036] In the formula, Provide a reference voltage value for the DC bus. A voltage reference value is given for each power unit converter; k j q is the droop curve coefficient for each power unit converter. PV q IV q DV and q Pi q Ii q Di These are the parameters for the average voltage and average current regulators, respectively.

[0037] As a preferred embodiment of the present invention, the voltage controller employs a non-singular exponential voltage variable structure control algorithm, comprising the following steps:

[0038] S31. Obtain the voltage loop tracking error e Vj for:

[0039]

[0040] S32. The switching function of the non-singular exponential voltage variable structure control algorithm is designed as follows:

[0041]

[0042] In the formula, η Vj >0; m Vj n Vj All are positive odd numbers; 1 <m Vj / n Vj <2;

[0043] S33, Based on the non-singular exponential voltage variable structure control algorithm, switch function σ Vj Its derivative can be expressed as

[0044]

[0045] S34, Design σ Vj The exponential law of convergence is:

[0046]

[0047] In the formula, γ Vj >0, ε Vj >0;

[0048] S35. Obtain the terminal current i of the j-th distributed power source using a current sensor. Lj ;

[0049] S36. Calculate the output of the non-singular exponential voltage variable structure control algorithm.

[0050]

[0051] In the formula, C j For the filter capacitor, C 0j ΔC is the nominal value of the filter capacitor. j =C j -C 0j Parameter Φ j Represented as:

[0052]

[0053] As a preferred embodiment of the present invention, the current controller employs a non-singular exponential current-variable structure control algorithm, comprising the following steps:

[0054] S41. Obtain the current loop tracking error e ij for:

[0055]

[0056] S42. The switching function for the non-singular exponential electrovariable structure control algorithm is:

[0057]

[0058] In the formula, η ij >0; m ij n ij All are positive odd numbers; 1 <m Vj / n Vj <2;

[0059] S43. Switching function σ according to the non-singular exponential electrorheological structure control algorithm. ij Its derivative can be expressed as

[0060]

[0061] S44, Design σ ij The exponential law of convergence is:

[0062]

[0063] In the formula, γ ij >0, ε ij >0;

[0064] S45. Obtain the terminal voltage V of the j-th distributed power source using a voltage sensor. sj ;

[0065] S46. Calculate the output of the non-singular exponential voltage variable structure control algorithm.

[0066]

[0067] In the formula, L j and R j Let L be the filter inductor and its internal resistance for the j-th distributed power source. 0j and R 0j L respectively j and R j The nominal value, ΔL j =L j -L 0j ΔR j =R j-R 0j , parameter Ψ j Represented as:

[0068]

[0069] The beneficial effects of this invention are as follows:

[0070] (1) Utilizing the nonlinear switching term v j To reconstruct system noise and uncertain disturbances, a nonlinear variable structure observer is designed. It provides accurate measurement parameters for multi-source power supply systems, eliminates the adverse effects of measurement deviations, and ensures the normal operation of the power supply system.

[0071] (2) The voltage and current deviation dual compensation algorithm based on the proportional integral derivative control of average voltage and current adds the average voltage controller and the average current regulator to the power distribution controller, which improves the traditional droop control method by using both voltage offset and slope adjustment methods. This not only greatly eliminates DC voltage deviation, but also improves the current sharing accuracy of multi-source systems.

[0072] (3) Output of non-singular exponential voltage-variable structure control algorithm and non-singular exponential current-variable structure control algorithm and The non-singular exponential reaching law is adopted, which has good voltage and current tracking performance, fast convergence speed, and improves the control performance and bus voltage robustness of multi-source power supply system.

[0073] (4) Nonlinear variable structure observer, power distribution controller, voltage loop controller and current loop controller coordinate with the control mode of multi-source power supply system to maintain the DC bus voltage stability and balance the energy of each distributed power source. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of a robust control device for nonlinear variable structure observation of a multi-source power supply system provided in one embodiment of the present invention. Detailed Implementation

[0075] 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.

[0076] The present invention is as follows Figure 1As shown, a robust control device for nonlinear variable structure observation of a multi-source power supply system is provided, including multiple distributed power sources, a power converter, a common bus, a current sensor, a voltage sensor, a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller. The output of the nonlinear variable structure observer is connected to the input of the power distributor; the output of the power distributor is connected to the input of the voltage controller; the output of the voltage controller is connected to the input of the current controller; the output of the current controller is connected to the input of the power converter's switching transistor; the distributed power sources are connected to the common bus through the power converter.

[0077] Multiple distributed power sources are connected to a common bus via a power converter. The power converter control loop consists of a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller.

[0078] The control method of the nonlinear variable structure observation robust control device for multi-source power supply system is as follows: the power distribution controller adopts the voltage and current deviation double compensation algorithm based on the proportional integral derivative control of average voltage and current; the voltage controller adopts the non-singular exponential voltage variable structure control algorithm; and the current controller adopts the non-singular exponential current variable structure control algorithm.

[0079] The design of a nonlinear variable structure observer includes the following steps:

[0080] S11. Considering only the converter output voltage, the state-space model of the j-th distributed power source is obtained as follows:

[0081]

[0082] y j (t)=C j x j (t)=V dcj

[0083] Wherein, the state variable x is taken j =[V dcj i Lj ] T V dcj Let i be the output voltage of the j-th power converter. Lj Let A be the terminal current of the j-th distributed power source, where j = 1, 2, ..., n. j B is the coefficient matrix of the state variables. j For the control variable coefficient matrix, C j To output the coefficient matrix of the variables, D j Let A be the coefficient matrix of the system's uncertainty terms. j ∈R n×n B j ∈R n×p C j ∈Rq×n , and D j ∈R n×k Where n>p≥q>k, assume matrix C j Full rank, function ξ j ||ξ represents the uncertainty in the j-th distributed power source. i (t,y,u)||<β, where β is a positive scalar;

[0084] S12. Based on the state-space model of the j-th distributed source, design the following nonlinear variable structure observer:

[0085]

[0086] The estimated output of the j-th distributed power system is:

[0087]

[0088] In the formula, V represents the state variable of the augmented system. dc and i Lj The estimate of v, and v j It is a nonlinear switching term with the following definition:

[0089]

[0090] Indicates the output estimation error; γ j It is a positive calibrator, γ j ∈R + Q 0j Q is the initial gain matrix of the nonlinear variable structure observer. 0j Symmetric and positive definite, Q 0j ∈R n×n ;

[0091] S13. Obtain the positive definite gain matrix Q of the nonlinear variable structure observer. j , making Among them, H j It conforms to the following linear matrix inequalities:

[0092]

[0093] in, D j It is a constant matrix, I j It is the identity matrix, α 0j The value of Q depends on j Properties of linear matrix inequalities;

[0094] S14. Design the gain matrix R of a nonlinear variable structure observer. qj Rpj and Q j as follows:

[0095] R qj =α 0j Q j -1 C j T (D j D j T ) -1

[0096]

[0097]

[0098] in,

[0099] S15. Obtain the state variable estimation error of the nonlinear variable structure observer. Its dynamic characteristics are as follows:

[0100]

[0101] The power distribution controller employs a dual compensation algorithm for voltage and current deviation based on proportional-integral-derivative control of average voltage and current, including the following steps:

[0102] S21, The output current i of the power converter is obtained by the current sensor and the voltage sensor respectively. dcj and output voltage V dcj ;

[0103] S22, based on the output current i of the j-th distributed power unit converter dcj and output voltage V dcj Calculate the average output current and voltage of the power unit converter respectively:

[0104]

[0105]

[0106] S23. The following is a dual compensation algorithm for the longitudinal intercept of voltage and current deviation based on proportional-integral-derivative control of average voltage and current:

[0107]

[0108] In the formula, Provide a reference voltage value for the DC bus. A voltage reference value is given for each power unit converter; k jq is the droop curve coefficient for each power unit converter. PV q IV q DV and q Pi q Ii q Di These are the parameters for the average voltage and average current regulators, respectively.

[0109] The voltage controller employs a non-singular exponential voltage variable structure control algorithm, which includes the following steps:

[0110] S31. Obtain the voltage loop tracking error e Vj for:

[0111]

[0112] S32. The switching function of the non-singular exponential voltage variable structure control algorithm is designed as follows:

[0113]

[0114] In the formula, η Vj >0; m Vj n Vj All are positive odd numbers; 1 <m Vj / n Vj <2;

[0115] S33, Based on the non-singular exponential voltage variable structure control algorithm, switch function σ Vj Its derivative can be expressed as

[0116]

[0117] S34, Design σ Vj The exponential law of convergence is:

[0118]

[0119] In the formula, γ Vj >0, ε Vj >0;

[0120] S35. Obtain the terminal current i of the j-th distributed power source using a current sensor. Lj ;

[0121] S36. Calculate the output of the non-singular exponential voltage variable structure control algorithm.

[0122]

[0123] In the formula, C j For the filter capacitor, C 0j ΔC is the nominal value of the filter capacitor.j =C j -C 0j Parameter Φ j Represented as:

[0124] The current controller employs a non-singular exponential current-varying structure control algorithm, including the following steps:

[0125] S41. Obtain the current loop tracking error e ij for:

[0126]

[0127] S42. The switching function for the non-singular exponential electrovariable structure control algorithm is:

[0128]

[0129] In the formula, η ij >0; m ij n ij All are positive odd numbers; 1 <m Vj / n Vj <2;

[0130] S43. Switching function σ according to the non-singular exponential electrorheological structure control algorithm. ij Its derivative can be expressed as

[0131]

[0132] S44, Design σ ij The exponential law of convergence is:

[0133]

[0134] In the formula, γ ij >0, ε ij >0;

[0135] S45. Obtain the terminal voltage V of the j-th distributed power source using a voltage sensor. sj ;

[0136] S46. Calculate the output of the non-singular exponential voltage variable structure control algorithm.

[0137]

[0138] In the formula, L j and R j Let L be the filter inductor and its internal resistance for the j-th distributed power source. 0j and R 0j L respectively j and Rj The nominal value, ΔL j =L j -L 0j ΔR j =R j -R 0j , parameter Ψ j Represented as:

[0139]

[0140] This invention proposes a nonlinear variable structure observer, a voltage and current deviation dual compensation algorithm based on proportional-integral-derivative control of average voltage and current, a non-singular exponential voltage variable structure control algorithm, and a non-singular exponential current variable structure control algorithm. These provide accurate parameters for the distributed controller, help the system resist noise and uncertain interference, and improve the system performance and bus voltage robustness.

[0141] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control method for a robust control device for nonlinear variable structure observation in a multi-source power supply system, characterized in that, The robust control device for nonlinear variable structure observation in a multi-source power supply system includes multiple distributed power sources, a power converter, a common bus, a current sensor, a voltage sensor, a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller. The output of the nonlinear variable structure observer is connected to the input of the power distributor; the output of the power distributor is connected to the input of the voltage controller; the output of the voltage controller is connected to the input of the current controller; the output of the current controller is connected to the input of the power converter's switching transistor; the distributed power sources are connected to the common bus through the power converter. Multiple distributed power sources are connected to a common bus through a power converter. The control loop of the power converter consists of a nonlinear variable structure observer, a power distribution controller, a voltage controller, and a current controller. The power distribution controller employs a voltage and current deviation dual compensation algorithm based on proportional-integral-derivative control of average voltage and current; the voltage controller employs a non-singular exponential voltage variable structure control algorithm; and the current controller employs a non-singular exponential current variable structure control algorithm. The design of the nonlinear variable structure observer includes the following steps: S11. Considering only the converter output voltage, the state-space model of the j-th distributed power source is obtained as follows: ； Wherein, the state variable x is taken j =[V dcj i Lj ] T V dcj Let i be the output voltage of the j-th power converter. Lj Let A be the terminal current of the j-th distributed power source, j=1,2,…n; j B is the coefficient matrix of the state variables. j For the control variable coefficient matrix, C j To output the coefficient matrix of the variables, D j Let A be the coefficient matrix of the system's uncertainty terms. j ∈R n×n B j ∈R n×p C j ∈R q×n , and D j ∈R n×k Where n>p≥q>k, assume matrix C j Full rank, function ξ j ||ξ represents the uncertainty in the j-th distributed power source. i (t, y, u)||< β, where β is a positive scalar; S12. Based on the state-space model of the j-th distributed source, design the following nonlinear variable structure observer: ； The estimated output of the j-th distributed power system is: ； In the formula, V represents the state variable of the augmented system. dc and i Lj The estimate of v, and v j It is a nonlinear switching term with the following definition: ； Indicates the output estimation error; γ j It is a positive calibrator, γ j ∈R + Q 0j Q is the initial gain matrix of the nonlinear variable structure observer. 0j Symmetric and positive definite, Q 0j ∈R n×n ; S13. Obtain the positive definite gain matrix of the nonlinear variable structure observer. , making Among them, H j It conforms to the following linear matrix inequalities: ； in, , D j It is a constant matrix, I j It is the identity matrix, α 0j The value of Q depends on j Properties of linear matrix inequalities; S14. Design the gain matrix R of a nonlinear variable structure observer. qj R pj and Q j as follows: ； ； ； in, ; S15. Obtain the state variable estimation error of the nonlinear variable structure observer. Its dynamic characteristics are as follows: 。 2. The control method of the nonlinear variable structure observation robust control device for a multi-source power supply system according to claim 1, characterized in that, The power distribution controller employs a dual compensation algorithm for voltage and current deviation based on proportional-integral-derivative control of average voltage and current, including the following steps: S21, The output current i of the power converter is obtained by the current sensor and the voltage sensor respectively. dcj and output voltage V dcj ; S22, based on the output current i of the j-th distributed power unit converter dcj and output voltage V dcj Calculate the average output current and voltage of the power unit converter respectively: ； ； S23. The following is a dual compensation algorithm for the longitudinal intercept of voltage and current deviation based on proportional-integral-derivative control of average voltage and current: ； In the formula, Provide a reference voltage value for the DC bus. A voltage reference value is given for each power unit converter; k j q is the droop curve coefficient for each power unit converter. PV q IV q DV and q Pi q Ii q Di These are the parameters for the average voltage and average current regulators, respectively.

3. The control method of the nonlinear variable structure observation robust control device for a multi-source power supply system according to claim 2, characterized in that, The voltage controller employs a non-singular exponential voltage variable structure control algorithm, including the following steps: S31. Obtain the voltage loop tracking error e Vj for: ； S32. The switching function of the non-singular exponential voltage variable structure control algorithm is designed as follows: ； In the formula, ; , All are positive odd numbers; ; S33, Switching function based on non-singular exponential voltage variable structure control algorithm Its derivative can be expressed as ； S34, Design The exponential law of convergence is: ； In the formula, γ Vj >0, ε Vj >0; S35. Obtain the terminal current i of the j-th distributed power source using a current sensor. Lj ; S36. Calculate the output of the non-singular exponential voltage variable structure control algorithm. : ； In the formula, C j For the filter capacitor, C 0j ΔC is the nominal value of the filter capacitor. j =C j -C 0j Parameter Φ j Represented as: 。 4. The control method of the nonlinear variable structure observation robust control device for a multi-source power supply system according to claim 3, characterized in that, The current controller employs a non-singular exponential current-varying structure control algorithm, including the following steps: S41. Obtain the current loop tracking error e ij for: ； S42. The switching function for the non-singular exponential electrovariable structure control algorithm is: ； In the formula, ; , All are positive odd numbers; ; S43. Switching function based on non-singular exponential electrorheological structure control algorithm Its derivative can be expressed as ； S44, Design The exponential law of convergence is: ； wherein γ ij > 0, ε ij > 0; S45. Obtain the terminal voltage V of the j-th distributed power source using a voltage sensor. sj ; S46. Calculate the output of the non-singular exponential voltage variable structure control algorithm. : ； In the formula, L j and R j Let L be the filter inductor and its internal resistance for the j-th distributed power source. 0j and R 0j L respectively j and R j The nominal value, ΔL j =L j -L 0j ΔR j =R j -R 0j , parameter Ψ j Represented as: 。

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