CN107346885B - An optimal control method for DC/DC bidirectional converter to stabilize DC bus voltage - Google Patents

An optimal control method for DC/DC bidirectional converter to stabilize DC bus voltage Download PDF

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CN107346885B
CN107346885B CN201710741509.5A CN201710741509A CN107346885B CN 107346885 B CN107346885 B CN 107346885B CN 201710741509 A CN201710741509 A CN 201710741509A CN 107346885 B CN107346885 B CN 107346885B
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directional inverter
mode
mathematical model
rule
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CN107346885A (en
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李鹏
李鑫明
李继红
张亮
王敏
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State Grid Zhejiang Electric Power Co Ltd
North China Electric Power University
Shaoxing Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
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State Grid Zhejiang Electric Power Co Ltd
North China Electric Power University
Shaoxing Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00Circuit arrangements for DC mains or DC distribution networks
    • H02J1/14Balancing the load in a network

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Abstract

A kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling: in the case where boosting and being depressured two kinds of operating modes, the affine nonlinear mathematical model of DC/DC bi-directional inverter is established;It is performance indicator that it is most short in the transfer time of the affine nonlinear mathematical model under boost operating mode and the state variable in the affine nonlinear mathematical model being depressured under operating mode, which to choose DC/DC bi-directional inverter, time optimal controller is constructed, timing-optimal control rule is sought;It is performance indicator that DC/DC bi-directional inverter, which is chosen, in the Quadratic Function Optimization of the affine nonlinear mathematical model under boost operating mode and the state variable in the affine nonlinear mathematical model being depressured under operating mode, state optimization adjuster is constructed, state optimization control law is sought;Fuzzy rule is established for timing-optimal control rule and state optimization control law, fuzzy self-adaption weight tuning controller is constructed, seeks the weight of timing-optimal control rule and state optimization control law.Present invention realization can be to the optimum control of DC/DC bi-directional inverter.

Description

A kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling
Technical field
The present invention relates to a kind of direct current bus voltage control methods.Stablize more particularly to a kind of DC/DC bi-directional inverter DC bus-bar voltage method for optimally controlling.
Background technique
The quantity of the ratio and DC load that are connected to the grid with new energy increasingly increases, and direct-current grid has become One of hot spot of research.The problem of in direct-current grid without the concern for angle stability and frequency stabilization, energy can be effectively reduced Measure conversion links.DC bus-bar voltage is the important indicator for evaluating the operation of direct-current grid normal table.Thus need to design phase The control strategy answered is to maintain DC bus-bar voltage to stablize.The energy-storage units in direct-current grid are usually chosen, it is bis- by DC/DC Carry out stable DC busbar voltage to inverter, and stabilizes the power swing in micro-capacitance sensor.
DC/DC bi-directional inverter has the characteristics that switch non-linearity, traditional control method do not consider its non-linear behavior. In addition, wish to use DC/DC bi-directional inverter can either stabilize power swing in engineering, DC bus-bar voltage is maintained, and can be with The shortest time completes the adjusting of transient process.Thus, it is necessary to research and develop a kind of direct current for taking into account regulating time and status adjustment Busbar voltage method for optimally controlling.
Summary of the invention
The technical problem to be solved by the invention is to provide a kind of direct-current grid environment that consideration has new energy to access Under, a kind of power swing stabilized in direct-current grid by DC/DC bi-directional inverter is provided, and maintain DC bus-bar voltage steady Fixed DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling.
The technical scheme adopted by the invention is that: a kind of DC/DC bi-directional inverter stable DC busbar voltage optimum control Method includes the following steps:
1) in the case where boosting and being depressured two kinds of operating modes, the affine nonlinear mathematics of DC/DC bi-directional inverter is established respectively Model;
2) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being dropped Pressing the transfer time of the state variable in the affine nonlinear mathematical model under operating mode most short is performance indicator, constructs the time Optimal controller seeks timing-optimal control rule;
3) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being dropped The Quadratic Function Optimization for pressing the state variable in the affine nonlinear mathematical model under operating mode is performance indicator, and building state is most Excellent adjuster seeks state optimization control law;
4) it is directed to the timing-optimal control rule that step 2) obtains and the state optimization control law that step 3) obtains is established and obscured Rule constructs fuzzy self-adaption weight tuning controller, seeks the power of timing-optimal control rule and state optimization control law respectively Weight.
In step 1) under boost operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under boost operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLWith ioRespectively represent energy storage side inductive current and direct-current grid equivalent load electric current, iLrefRepresent the reference of energy storage side inductive current Value, dtRepresentation switch pipe S1Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytIt represents and rises The output function of the differential equation of DC/DC bi-directional inverter under die pressing type;
The integral term that output function is introduced to the differential equation of the DC/DC bi-directional inverter under boost operating mode, obtains Following formula:
Wherein, ztFor the state variable under boost mode in DC/DC bi-directional inverter affine nonlinear mathematical model;zt1Generation The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under table boost modet2Represent DC/DC under boost mode The departure of bi-directional inverter energy storage side inductive current;
By the liter after the differential equation and introducing output function integral term of the DC/DC bi-directional inverter under boost operating mode The differential equation under operating mode is pressed, affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is obtained It is as follows:
Wherein:vtFor the pre-control variable under boost mode, vtWith dtRelationship be shown below:
In step 1) in the case where being depressured operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under decompression operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLWith ioRespectively represent energy storage side inductive current and direct-current grid equivalent load electric current, iLrefRepresent the reference of energy storage side inductive current Value, dkRepresentation switch pipe S2Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytRepresent drop The output function of the differential equation of DC/DC bi-directional inverter under die pressing type;
The integral term that output function is introduced to the differential equation of DC/DC bi-directional inverter under decompression operating mode, obtains down Formula:
Wherein, zkFor the state variable under decompression mode in DC/DC bi-directional inverter affine nonlinear mathematical model.zk1Generation The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under table decompression modek2Represent DC/DC under decompression mode The departure of bi-directional inverter energy storage side inductive current;
By being depressured after the differential equation of DC/DC bi-directional inverter under decompression operating mode and the integral term of introducing output function The differential equation under operating mode, obtain DC/DC bi-directional inverter the affine nonlinear mathematical model being depressured under operating mode such as Under:
Wherein:vkFor the pre-control variable under decompression mode, vkWith dkRelationship be shown below:
Step 2) includes:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being depressured The time that state variable is transferred to stable state from original state in affine nonlinear mathematical model under operating mode is most short to be Performance indicator, the performance indicator such as following formula:
Define the switching curve equation such as following formula of timing-optimal control:
Wherein, under boost mode, z1=zt1Represent DC/DC bi-directional inverter energy storage side inductive current under boost mode The integral of departure, z2=zt2Represent the departure of DC/DC bi-directional inverter energy storage side inductive current under boost mode;It is being depressured Under mode, z1=zk1Represent the integral of the departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode, z2=zk2 The departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode is represented, S indicates switching curve function, J representative It can index;
Define timing-optimal control rule such as following formula:
Wherein, under boost mode, v=vt, y=yt;vtAnd ytRespectively indicate pre-control variable and boosting mould under boost mode Output function under formula;In buck mode, v=vk, y=yk;vkAnd ykRespectively indicate pre-control variable and decompression mould under decompression mode Output function under formula, sgn indicate sign function.
Step 3) includes:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being depressured The Quadratic Function Optimization of state variable is performance indicator in affine nonlinear mathematical model under operating mode, and formula is as follows:
Wherein, R and Q is respectively the weight matrix of pre-control variable and state variable;Under boost mode, z=zt, v=vt; ztAnd vtRespectively indicate under boost mode state variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model; In buck mode, z=zk, v=vk;zkAnd vkRespectively indicate DC/DC bi-directional inverter affine nonlinear mathematics under decompression mode State variable and pre-control variable in model, J indicate performance indicator;
State optimization control law such as following formula in the case where Quadratic Function Optimization is performance indicator:
V=-Kz=-R-1BTP*z (13)
Wherein, each symbol definition is as follows, and K is state feedback matrix, P*For the solution of Riccati equation, R is pre-control variable power Weight matrix, B are the input matrix in DC/DC mathematical model;Under boost mode, z=zt, v=vt;ztAnd vtRespectively indicate liter State variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model under die pressing type;In buck mode, z =zk, v=vk;zkAnd vkRespectively indicate under decompression mode state variable in DC/DC bi-directional inverter affine nonlinear mathematical model With pre-control variable.
Step 4) includes:
The departure of DC/DC bi-directional inverter energy storage side inductive current is set as input quantity, corresponding fuzzy domain be [- 0.3,0.3];The shared weight of timing-optimal control rule is output quantity, and corresponding fuzzy domain is [0,1];Timing-optimal control The sum of weight coefficient controlled with state optimization is 1;Fuzzy rule is established, fuzzy self-adaption weight association is constructed according to fuzzy rule Controller is adjusted, the power of timing-optimal control and state optimization control is determined by the output of fuzzy self-adaption weight tuning controller Weight.
The fuzzy rule is as follows:
Rule 1: if z2For NL, then ρ is L;
Rule 2: if z2For NM, then ρ is M;
Rule 3: if z2For NS, then ρ is S;
Rule 4: if z2For Z, then ρ is VS;
Rule 5: if z2For PS, then ρ is S;
Rule 6: if z2For PM, then ρ is M;
Rule 7: if z2For PL, then ρ is L;
Wherein: each symbol definition is as follows, and NL represents negative big, and NM is represented in negative, and NS representative is born small, and Z is representing zero, PS and representing just Small, PM represents center, and PL represents honest;Under boost mode, z2=zt2Represent DC/DC bi-directional inverter energy storage under boost mode The departure of side inductive current;In buck mode, z2=zk2Represent DC/DC bi-directional inverter energy storage side inductance under decompression mode The departure of electric current, ρ represent the shared weight of timing-optimal control rule.
A kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling of the invention has following beneficial Effect:
(1) method of the invention can fully consider the nonlinear characteristic of DC/DC bi-directional inverter, and boosting and be depressured Under two kinds of operating modes, the optimum control to DC/DC bi-directional inverter is realized;
(2) time optimal controller designed in method of the invention, the direct current in transient process that can effectively shorten are female The transit time of line voltage, DC bus-bar voltage is made to be quickly restored to reference point;
(3) state optimization adjuster designed in method of the invention can reduce DC bus electricity in transient process The hyperharmonic number of oscillation of the quantity of states such as pressure and inductive current, and inhibit by timing-optimal control bring Flutter Problem;
(4) fuzzy self-adaption weight tuning controller designed in method of the invention, can adaptively be the time Optimal controller and state optimization adjuster distribute weight coefficient, to guarantee pair of state transfer time and status adjustment process Re-optimization.
Detailed description of the invention
Fig. 1 is DC/DC bi-directional inverter topological diagram;
Fig. 2 is that time optimal controller realizes block diagram;
Fig. 3 is that fuzzy self-adaption weight tuning controller realizes block diagram;
Fig. 4 is direct-current grid typical topology figure;
Fig. 5 is voltage waveform comparison waveform diagram under three kinds of control modes under the conditions of embodiment 1;
Fig. 6 is the energy storage side inductive current waveform obtained under the conditions of embodiment 1 by control method of the present invention;
Fig. 7 is the DC bus-bar voltage waveform obtained under the conditions of embodiment 2 by control method of the present invention;
Fig. 8 is the energy storage side inductive current waveform obtained under the conditions of embodiment 2 by control method of the present invention.
Specific embodiment
It is optimal to a kind of DC/DC bi-directional inverter stable DC busbar voltage of the invention below with reference to embodiment and attached drawing Control method is described in detail.
A kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling of the invention, includes the following steps:
1) in the case where boosting and being depressured two kinds of operating modes, the affine nonlinear mathematics of DC/DC bi-directional inverter is established respectively Model;Wherein, DC/DC bi-directional inverter topological diagram is as shown in Figure 1.
(1) under boost operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under boost operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLWith ioRespectively represent energy storage side inductive current and direct-current grid equivalent load electric current, iLrefRepresent the reference of energy storage side inductive current Value, dtRepresentation switch pipe S1Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytIt represents and rises The output function of the differential equation of DC/DC bi-directional inverter under die pressing type.
The integral term that output function is introduced to the differential equation of the DC/DC bi-directional inverter under boost operating mode, obtains Following formula:
Wherein, ztFor the state variable under boost mode in DC/DC bi-directional inverter affine nonlinear mathematical model;zt1Generation The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under table boost modet2Represent DC/DC under boost mode The departure of bi-directional inverter energy storage side inductive current.
By the liter after the differential equation and introducing output function integral term of the DC/DC bi-directional inverter under boost operating mode The differential equation under operating mode is pressed, affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is obtained It is as follows:
Wherein:vtFor the pre-control variable under boost mode, vtWith dtRelationship be shown below:
(2) in the case where being depressured operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under decompression operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLWith ioRespectively represent energy storage side inductive current and direct-current grid equivalent load electric current, iLrefRepresent the reference of energy storage side inductive current Value, dkRepresentation switch pipe S2Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytRepresent drop The output function of the differential equation of DC/DC bi-directional inverter under die pressing type.
The integral term that output function is introduced to the differential equation of DC/DC bi-directional inverter under decompression operating mode, obtains down Formula:
Wherein, zkFor the state variable under decompression mode in DC/DC bi-directional inverter affine nonlinear mathematical model.zk1Generation The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under table decompression modek2Represent DC/DC under decompression mode The departure of bi-directional inverter energy storage side inductive current.
By being depressured after the differential equation of DC/DC bi-directional inverter under decompression operating mode and the integral term of introducing output function The differential equation under operating mode, obtain DC/DC bi-directional inverter the affine nonlinear mathematical model being depressured under operating mode such as Under:
Wherein:vkFor the pre-control variable under decompression mode, vkWith dkRelationship be shown below:
2) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being dropped Pressing the transfer time of state variable in the affine nonlinear mathematical model under operating mode most short is performance indicator, and the building time is most Excellent controller seeks timing-optimal control rule;Include:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being depressured The time that state variable is transferred to stable state from original state in affine nonlinear mathematical model under operating mode is most short to be Performance indicator, the performance indicator such as following formula:
Define the switching curve equation such as following formula of timing-optimal control:
Wherein, under boost mode, z1=zt1Represent DC/DC bi-directional inverter energy storage side inductive current under boost mode The integral of departure, z2=zt2Represent the departure of DC/DC bi-directional inverter energy storage side inductive current under boost mode;It is being depressured Under mode, z1=zk1Represent the integral of the departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode, z2=zk2 The departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode is represented, S indicates switching curve function, J representative It can index.
Define timing-optimal control rule such as following formula:
Wherein, under boost mode, v=vt, y=yt;vtAnd ytRespectively indicate pre-control variable and boosting mould under boost mode Output function under formula;In buck mode, v=vk, y=yk;vkAnd ykRespectively indicate pre-control variable and decompression mould under decompression mode Output function under formula, sgn indicate sign function.
Time optimal controller realizes that block diagram is as shown in Figure 2.
3) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being dropped The Quadratic Function Optimization for pressing state variable in the affine nonlinear mathematical model under operating mode is performance indicator, constructs state optimization Adjuster seeks state optimization control law;Include:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and is being depressured The Quadratic Function Optimization of state variable is performance indicator in affine nonlinear mathematical model under operating mode, and formula is as follows:
Wherein, R and Q is respectively the weight matrix of pre-control variable and state variable.Under boost mode, z=zt, v=vt; ztAnd vtRespectively indicate under boost mode state variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model; In buck mode, z=zk, v=vk;zkAnd vkRespectively indicate DC/DC bi-directional inverter affine nonlinear mathematics under decompression mode State variable and pre-control variable in model, J indicate performance indicator.
State optimization control law such as following formula in the case where Quadratic Function Optimization is performance indicator:
V=-Kz=-R-1BTP*z (13)
Wherein, each symbol definition is as follows, and K is state feedback matrix, P*For the solution of Riccati equation, R is pre-control variable power Weight matrix, B are the input matrix in DC/DC mathematical model;Under boost mode, z=zt, v=vt;ztAnd vtRespectively indicate liter State variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model under die pressing type;In buck mode, z =zk, v=vk;zkAnd vkRespectively indicate under decompression mode state variable in DC/DC bi-directional inverter affine nonlinear mathematical model With pre-control variable.
4) it is directed to the timing-optimal control rule that step 2) obtains and the state optimization control law that step 3) obtains is established and obscured Rule constructs fuzzy self-adaption weight tuning controller, seeks the power of timing-optimal control rule and state optimization control law respectively Weight.Include:
The departure of DC/DC bi-directional inverter energy storage side inductive current is set as input quantity, corresponding fuzzy domain be [- 0.3,0.3];The shared weight of timing-optimal control rule is output quantity, and corresponding fuzzy domain is [0,1];Timing-optimal control The sum of weight coefficient controlled with state optimization is 1;Fuzzy rule is established, fuzzy self-adaption weight association is constructed according to fuzzy rule Controller is adjusted, the power of timing-optimal control and state optimization control is determined by the output of fuzzy self-adaption weight tuning controller Weight.Fuzzy self-adaption weight tuning controller realizes that block diagram is as shown in Figure 3.
The fuzzy rule is as follows:
Rule 1: if z2For NL, then ρ is L;
Rule 2: if z2For NM, then ρ is M;
Rule 3: if z2For NS, then ρ is S;
Rule 4: if z2For Z, then ρ is VS;
Rule 5: if z2For PS, then ρ is S;
Rule 6: if z2For PM, then ρ is M;
Rule 7: if z2For PL, then ρ is L;
Wherein: each symbol definition is as follows, and NL represents negative big, and NM is represented in negative, and NS representative is born small, and Z is representing zero, PS and representing just Small, PM represents center, and PL represents honest.Under boost mode, z2=zt2Represent DC/DC bi-directional inverter energy storage under boost mode The departure of side inductive current;In buck mode, z2=zk2Represent DC/DC bi-directional inverter energy storage side inductance under decompression mode The departure of electric current, ρ represent the shared weight of timing-optimal control rule.
Embodiment is given below.
Under DC micro-electric web frame shown in Fig. 4, related embodiment is provided.Wherein, parameters are as follows: AC network Voltage 10kV, transformer voltage ratio 10kV/220V, DC bus voltage rating 560V, DC/DC bi-directional inverter switching frequency 10kHz, energy-storage units port voltage 250V.
Embodiment 1: when system is run to 1s, active power is uprushed 100kW in direct-current grid.The two-way change of current of DC/DC Device uses conventional PI control mode, linear optimal contro8 (LQR control), and DC bus is electric when mentioned method for optimally controlling of the invention Pressure comparison waveform is as shown in Figure 5.Energy storage side inductive current waveform is as shown in Figure 6 under the mentioned optimum control of the present invention.
As seen from Figure 5, it compared to conventional PI control mode and linear optimal contro8 mode, is mentioned in the present invention optimal DC bus-bar voltage under control method has shorter regulating time, and there is no oscillations in the transient process that voltage is adjusted Phenomenon, overshoot is in engineering allowed band.As seen from Figure 6, under the mentioned method of the present invention, energy-storage units can be from sky Not busy mode quick response movement, starts to charge, and chatter phenomenon does not occur in charging current, meets actual motion requirement.
Embodiment 2: when system is run to 1s, active power is uprushed 80kW in direct-current grid, DC load when 1.5s DC load is further added by 100kW when increase 80kW, 2s.DC/DC bi-directional inverter is using the mentioned method for optimally controlling of the present invention, directly It flows busbar voltage waveform and inductive current waveform difference in energy storage side is as shown in Figure 7 and Figure 8.
It is worked under two kinds of operating modes of decompression and boosting by DC/DC bi-directional inverter it can be seen from Fig. 7 and Fig. 8, it can be with Effectively DC bus-bar voltage is maintained to stablize, and can be realized that regulating time is most short, and overshoot is sufficiently small, gone out without oscillatory occurences It is existing.

Claims (7)

1. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling, which is characterized in that including walking as follows It is rapid:
1) in the case where boosting and being depressured two kinds of operating modes, the affine nonlinear mathematical model of DC/DC bi-directional inverter is established respectively;
2) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and in decompression work It is performance indicator that the transfer time of the state variable in affine nonlinear mathematical model under operation mode is most short, constructs time optimal Controller seeks timing-optimal control rule;
3) affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and in decompression work The Quadratic Function Optimization of the state variable in affine nonlinear mathematical model under operation mode is performance indicator, constructs state optimization tune Device is saved, state optimization control law is sought;
4) it is directed to the timing-optimal control rule that step 2) obtains and the state optimization control law that step 3) obtains establishes fuzzy rule, Fuzzy self-adaption weight tuning controller is constructed, seeks the weight of timing-optimal control rule and state optimization control law respectively.
2. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 1, special Sign is, in step 1) under boost operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under boost operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLAnd ioPoint Energy storage side inductive current and direct-current grid equivalent load electric current, i are not representedLrefRepresent the reference value of energy storage side inductive current, dt Representation switch pipe S1Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytRepresent boosting mould The output function of the differential equation of DC/DC bi-directional inverter under formula;
The integral term that output function is introduced to the differential equation of the DC/DC bi-directional inverter under boost operating mode, obtains following formula:
Wherein, ztFor the state variable under boost mode in DC/DC bi-directional inverter affine nonlinear mathematical model;zt1It represents and rises The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under die pressing typet2It is two-way to represent DC/DC under boost mode The departure of inverter energy storage side inductive current;
By the boosting work after the differential equation and introducing output function integral term of the DC/DC bi-directional inverter under boost operating mode It is as follows to obtain affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode for the differential equation under operation mode:
Wherein:vtFor the pre-control variable under boost mode, vtWith dtRelationship be shown below:
3. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 1, special Sign is, in step 1) in the case where being depressured operating mode, the affine nonlinear mathematical model for establishing DC/DC bi-directional inverter includes:
The differential equation that column write DC/DC bi-directional inverter under decompression operating mode is as follows:
Wherein, each symbol definition is as follows: usAnd udcRespectively represent energy-storage units exit potential and DC bus-bar voltage, iLAnd ioPoint Energy storage side inductive current and direct-current grid equivalent load electric current, i are not representedLrefRepresent the reference value of energy storage side inductive current, dk Representation switch pipe S2Duty ratio, L represents energy-storage units side inductance, and C represents DC bus equivalent capacity, ytRepresent decompression mould The output function of the differential equation of DC/DC bi-directional inverter under formula;
The integral term that output function is introduced to the differential equation of DC/DC bi-directional inverter under decompression operating mode, obtains following formula:
Wherein, zkFor the state variable under decompression mode in DC/DC bi-directional inverter affine nonlinear mathematical model;zk1Represent drop The integral of the departure of DC/DC bi-directional inverter energy storage side inductive current, z under die pressing typek2It is two-way to represent DC/DC under decompression mode The departure of inverter energy storage side inductive current;
By being depressured work after the differential equation of DC/DC bi-directional inverter under decompression operating mode and the integral term of introducing output function It is as follows in the affine nonlinear mathematical model being depressured under operating mode to obtain DC/DC bi-directional inverter for the differential equation under mode:
Wherein:vkFor the pre-control variable under decompression mode, vkWith dkRelationship be shown below:
4. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 1, special Sign is that step 2) includes:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and in decompression work The time that state variable is transferred to stable state from original state in affine nonlinear mathematical model under mode is most short for performance Index, the performance indicator such as following formula:
Define the switching curve equation such as following formula of timing-optimal control:
Wherein, under boost mode, z1=zt1Represent the deviation of DC/DC bi-directional inverter energy storage side inductive current under boost mode The integral of amount, z2=zt2Represent the departure of DC/DC bi-directional inverter energy storage side inductive current under boost mode;In decompression mode Under, z1=zk1Represent the integral of the departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode, z2=zk2It represents The departure of DC/DC bi-directional inverter energy storage side inductive current under decompression mode, S indicate that switching curve function, J indicate that performance refers to Mark;
Define timing-optimal control rule such as following formula:
Wherein, under boost mode, v=vt, y=yt;vtAnd ytIt respectively indicates under boost mode under pre-control variable and boost mode Output function;In buck mode, v=vk, y=yk;vkAnd ykIt respectively indicates under decompression mode under pre-control variable and decompression mode Output function, sgn indicate sign function.
5. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 1, special Sign is that step 3) includes:
Affine nonlinear mathematical model of the DC/DC bi-directional inverter under boost operating mode is chosen respectively and in decompression work The Quadratic Function Optimization of state variable is performance indicator in affine nonlinear mathematical model under mode, and formula is as follows:
Wherein, R and Q is respectively the weight matrix of pre-control variable and state variable;Under boost mode, z=zt, v=vt;ztAnd vt Respectively indicate under boost mode state variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model;It is dropping Under die pressing type, z=zk, v=vk;zkAnd vkRespectively indicate DC/DC bi-directional inverter affine nonlinear mathematical model under decompression mode Middle state variable and pre-control variable, J indicate performance indicator;
State optimization control law such as following formula in the case where Quadratic Function Optimization is performance indicator:
V=-Kz=-R-1BTP*z (13)
Wherein, each symbol definition is as follows, and K is state feedback matrix, P*For the solution of Riccati equation, R is pre-control variable weight square Battle array, B are the input matrix in DC/DC mathematical model;Under boost mode, z=zt, v=vt;ztAnd vtRespectively indicate boosting mould State variable and pre-control variable in DC/DC bi-directional inverter affine nonlinear mathematical model under formula;In buck mode, z=zk, V=vk;zkAnd vkRespectively indicate under decompression mode in DC/DC bi-directional inverter affine nonlinear mathematical model state variable and pre- Control variable.
6. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 1, special Sign is that step 4) includes:
The departure of DC/DC bi-directional inverter energy storage side inductive current is set as input quantity, corresponding fuzzy domain be [- 0.3, 0.3];The shared weight of timing-optimal control rule is output quantity, and corresponding fuzzy domain is [0,1];Timing-optimal control and shape The sum of weight coefficient of state optimum control is 1;Fuzzy rule is established, fuzzy self-adaption weight is constructed according to fuzzy rule and coordinates control Device processed is determined the weight of timing-optimal control and state optimization control by the output of fuzzy self-adaption weight tuning controller.
7. a kind of DC/DC bi-directional inverter stable DC busbar voltage method for optimally controlling according to claim 6, special Sign is that the fuzzy rule is as follows:
Rule 1: if z2For NL, then ρ is L;
Rule 2: if z2For NM, then ρ is M;
Rule 3: if z2For NS, then ρ is S;
Rule 4: if z2For Z, then ρ is VS;
Rule 5: if z2For PS, then ρ is S;
Rule 6: if z2For PM, then ρ is M;
Rule 7: if z2For PL, then ρ is L;
Wherein: each symbol definition is as follows, and NL represents negative big, and NM is represented in negative, NS representative bear it is small, Z represent zero, PS represent it is just small, PM represents center, and PL represents honest;Under boost mode, z2=zt2Represent DC/DC bi-directional inverter energy storage side under boost mode The departure of inductive current;In buck mode, z2=zk2Represent inductance electricity in DC/DC bi-directional inverter energy storage side under decompression mode The departure of stream, ρ represent the shared weight of timing-optimal control rule.
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