CN106043173A - Real-time power distribution control method for vehicle-mounted hybrid power system - Google Patents

Abstract

The invention discloses a real-time power distribution control method for a vehicle-mounted hybrid power system. In order to get rid of the characteristic that a main energy system dynamic response is slow and deal with the actual dynamic working condition changed quickly and suddenly, key feature parameters of the hybrid power system are estimated on line through a self-adaption updating law, an online updating law of the virtual load current is established on the basis of key feature parameter estimated values, and real-time power distribution is conducted on an energy source. By the adoption of the method, online tracking of dynamic power requirements can be achieved, meanwhile, dynamic restraints of the system are fully considered, the safety of the hybrid power system can be better guaranteed, and the service life of the hybrid power system can be better prolonged.

Description

A kind of realtime power distribution control method of vehicle-mounted hybrid power system

Technical field

The invention belongs to the field of intelligent control of vehicle, especially relate to the real-time merit of a kind of vehicle-mounted hybrid power system Rate distribution control method.

Background technology

Along with science and technology progress and development, some emerging energy resource systems, as fuel cell system, cell power systems with And super capacitor system, the advantage of zero-emission high with its energy transformation ratio, it is applied to new forms of energy car the most widely In dynamical system.For the specific advantages of different energy sources system, in actual application usually by two kinds of different energy sources systems respectively As main source of energy and auxiliary energy system carry out mixing constitute onboard power systems (such as fuel cell-cell hybrid power system, Battery-super capacitance mixed dynamic system), and then the dynamic response to the frequently load power demand of sudden change of the system of lifting Energy and its energy conversion efficiency.In hybrid power system, the energy resource system as main source of energy typically has energy density height, But the feature of power density low (power output response speed is slow), it means that the dynamic responding speed of main source of energy is slower.As Complementation, it is low that auxiliary energy system has energy density, the feature of power density high (power output fast response time).

It is the structural representation of the hybrid power system that the present invention is studied shown in Fig. 1, wherein main source of energy and supplementary energy Couple in parallel, be then attached on system bus, provide energy for load.This hybrid power system is with it To the response of high frequency load power demand, the fast and feature of low cost, is adopted by vehicle-mounted hybrid power system developer widely With.

In the case of supplementary energy is cell power systems, owing to the state-of-charge (SOC) of battery can not be surveyed, current Control method it cannot be guaranteed that regulate control the most accurately to battery SOC.But whether SOC reflection battery overcharges or crosses and put One important indicator, therefore the regulation to SOC controls significant, and the accurately control of SOC can be vehicle-mounted mixing simultaneously The tension management scheme of dynamical system provides degree of freedom more.

Summary of the invention

In order to solve the deficiencies in the prior art, the invention provides the realtime power distribution of a kind of vehicle-mounted hybrid power system Control method, for characteristic and the actual dynamic operation condition of rapid mutation of main energy source system dynamics low-response, based on adaptive Answer control theory to carry out realtime power distribution to control, main source of energy output electric current is designed, and then realizes realtime power distribution Control, thus solve vehicle-mounted hybrid power system and the Real-time and Dynamic of load power demand is estimated and tracking problem and to mixed The safety protection problem of assembly system.

The technical solution used in the present invention is to use following steps:

1) key characterization parameter to hybrid power system uses adaptive updates rule to carry out On-line Estimation；

2) build virtual negative current-carrying online updating rule based on key characterization parameter estimated value, energy resource system is carried out reality Time power distribution.

It is load that the hybrid power system of the present invention refer to two energy resource systems carries out coupling common in parallel The dynamical system of energy is provided, can be vehicle-mounted dual energy sources (main source of energy+supplementary energy) electric hybrid system in being embodied as System, such as fuel cell-cell hybrid power system, battery-super capacitance mixed dynamic system.At this type hybrid dynamical system In system, the only output electric current of main source of energy can be directly controlled, so referred to as current mode main source of energy.

Described key characterization parameter includes supplementary energy equivalent internal resistance and load equivalent resistance.

Described step 1) specifically supplementary energy equivalent internal resistance is used below equation (1) adaptive updates that represents restrain into Row is estimated:

Wherein,Represent supplementary energy adaptive factor, c₁Represent supplementary energy intermediate variable, R₀Represent supplementary energy etc. Effect internal resistance actual value, R₀Represent supplementary energy equivalent internal resistance estimated value；γ₁It is supplementary energy adaptive gain normal number, needs Actual application is the most artificially chosen；R_{0, max}WithRepresent supplementary energy equivalent internal resistance R respectively₀The upper bound and under Boundary, be all on the occasion of；V is bus voltage,For supplementary energy open-circuit voltage setting value, corresponding to auxiliary energy state-of-charge (SOC)；i_fFor auxiliary energy source electric current,Represent actual loading electric current i_lWith designed dummy load electric currentDeviation, i.e.

So that supplementary energy equivalent internal resistance estimated value R₀At supplementary energy equivalent internal resistance actual value R₀Bound scope Within, it is

c_{0, min}≤R₀≤R_{0, max} (2)

Wherein, upper bound R_{0, max}More than supplementary energy equivalent internal resistance actual value R₀Supremum, lower bound R_{0, min}More than auxiliary energy Source equivalent internal resistance actual value R₀Infimum.

In actual applications, R_{0, max}With R_{0, min}Be chosen at and meet condition R_{0, min}≤R₀≤R_{0, max}In the case of, want simultaneously Consider the Actual Control Effect of Strong of control method, this also means that R_{0, max}Selection supplementary energy to be suitably larger than equivalent internal resistance R₀Supremum, accordingly, R_{0, min}Choose supplementary energy equivalent internal resistance R to be suitably less than₀Infimum.

Described step 1) specifically:

1.1) to load equivalent resistance by estimate load equivalent conductance method obtain, load equivalent conductance use with The adaptive updates rule that lower formula (3) represents is estimated:

Wherein, q₂Represent the loaded self-adaptive factor, c₂Represent load intermediate variable, G_lFor load equivalent conductance actual value, expire FootR_lFor load equivalent resistance actual value,For load equivalent conductance estimated value；γ₂Be loaded self-adaptive gain just Constant, needs the most artificially to choose；Represent dummy load electric current；With G_{L, min}It is respectively It is load equivalent conductance actual value G_lThe upper bound and lower bound, be all on the occasion of；Represent actual loading electric current i_lVirtual with designed Load currentDeviation, i.e.

So that load equivalent conductance estimated valueAt load equivalent conductance actual value G_lBound within the scope of, i.e. For:

$G_{l,\min }\≤{\hat{G}}_l\≤G_{l,\max }---\left(4\right)$

Wherein, upper bound G_{L, max}With lower bound G_{L, min}It is by load equivalent resistance actual value R_lBound determine, meet:

$G_{l,\max }-\frac{1}{R_{l,\min }},G_{l,\min }-\frac{1}{R_{l,\max }}---\left(5\right)$

Wherein,WithRepresent load equivalent resistance actual value R respectively_lThe upper bound and lower bound,WithWith actual load current i_lRelevant；

According to hybrid electric vehicle bus current situation in actual motion, can be according to above formula to R_lBound make Determine.

1.2) equivalent conductance estimated value is being obtainedAfter, utilize formulaIt is calculated load equivalent resistance to estimate Value

Described step 2) specifically:

2.1) the online updating rule using below equation (7) to represent calculates and obtains dummy load electric current

Wherein, α₁Represent load tracking gain constant, α₂Represent that supplementary energy SOC regulates storage gain constant, be all basis The normal number that experience sets.Accordingly,It is referred to as load tracking item,It is referred to as auxiliary Energy SOC regulates integral term.

The dummy load electric current that formula obtainsIt is the low-frequency component of load current, will be used for designing the output electricity of main source of energy Stream reference value.

2.2) use below equation (8) to calculate and obtain main source of energy output current design value

Wherein, β represents that supplementary energy SOC regulates proportional gain constant, is the normal number rule of thumb set.It is referred to as supplementary energy SOC and regulates proportional.

Two main targets controlled in real time for vehicle hybrid system:

1) dynamic tracking to load power demand is realized；

On the one hand this be mainly reflected in load equivalent resistance R_lCarry out the estimated value estimating to obtain load equivalent resistance Then utilizeStructure load tracking project in formula (7):

2) meet each subsystem safety indexes in hybrid power system, thus protect security of system to extend it and use the longevity Life.

Two aspects are mainly had for security of system index to be met:

1) ensure that main energy source power output response speed is less than its ceiling restriction, and then protect its security of system, extend Its service life.

The satisfied of this index is by actual loading equivalent resistance R_lEstimate realize because rule of thumb fitting Locality chooses gain constant γ₁, α₁, α₁, after β, utilize the estimated value of load equivalent resistance obtained by the present inventionCan be to reality Border load equivalent resistance R_lCarrying out smooth, this can be as seen from Figure 2.Therefore, based onObtainAlso there is smooth property Matter, so can ensure that based onThe main source of energy output current design value obtainedResponse speed less than its ceiling restriction.

2) preventing supplementary energy from occurring overcharging and the phenomenon of over-discharge, supplementary energy SOC to be controlled is necessarily In the range of, or hold it in the vicinity of a setting value.

This index is accomplished by: the SOC of supplementary energy and its open-circuit voltage also exist letter one to one Number relation, after obtaining the supplementary energy SOC respective function relation with supplementary energy open-circuit voltage, it is possible to by auxiliary energy The control of source open-circuit voltage equally realizes the control to supplementary energy SOC.In view of in reality, supplementary energy open-circuit voltage is not Can survey, the present invention utilize the estimation to supplementary energy equivalent internal resistance and bus voltage V long-pending to build supplementary energy SOC regulation Subitem realizes the control to supplementary energy SOC with supplementary energy SOC regulation proportional.

The invention has the beneficial effects as follows:

The inventive method need not the model parameter to system in actual vehicular applications and carries out accurate identification, thus significantly Reduce and it is realized difficulty, contribute to the robustness of lifting system.

The present invention can regulate control to immesurable supplementary energy SOC, the most accurately in hybrid power system The power demand of energy source carries out reasonable distribution, and then the dynamic response meeting the output of its power limits.

The present invention can realize the on-line tracing to dynamic power demand, has taken into full account the dynamic constrained of system simultaneously, It is of value to safety and the prolongation in service life ensureing hybrid power system.

Accompanying drawing explanation

Fig. 1 is the Vehicular hybrid power system structure chart that the present invention is targeted.

Fig. 2 is the estimation effect figure in Matlab/Simulink emulates to load resistance.

Fig. 3 is the control design sketch in Matlab/Simulink emulates to supplementary energy SOC, and target SOC is 0.6.

Fig. 4 is the current-responsive curve of two energy sources in test experiments.

Detailed description of the invention

Below in conjunction with detailed description of the invention and compare accompanying drawing the present invention is described in detail.

Following two embodiment all uses the inventive method to implement, and its specific implementation process is as follows:

Embodiment 1

Owing to the load equivalent resistance in reality and supplementary energy SOC can not survey, so by Matlab/ Simulink builds fuel cell-lithium battery hybrid power system phantom, the control effect of the present invention is tested Card.

Figure it is seen that the load equivalent resistance estimated value that the present invention is carriedCan be to the actual loading etc. of sudden change Effect resistance carries out smooth, thus is conducive to being met the main source of energy output current design value of response speed constraint.When stable state, Load equivalent resistance estimated valueLevel off to actual loading equivalent resistance, indicate the effectiveness carried from using more new law.

Fig. 3 is the present invention control effect to supplementary energy SOC.The setting value of supplementary energy SOC is 0.6, according to auxiliary Energy SOC and the corresponding relation of supplementary energy open-circuit voltage, supplementary energy open-circuit voltage setting valueIt is set to 50.06V.Fig. 3 Show that supplementary energy SOC can be readjusted by the present invention after load changing makes supplementary energy SOC deviation setting value 0.6 Near setting value 0.6.

Embodiment 2

The present invention is also applied on actual fuel cell-lithium battery hybrid power Caddy and has been verified.Fig. 4 In be the fuel cell as main source of energy and the output current-responsive curve of the lithium battery as supplementary energy, it can be seen that main energy The response speed of source electric current is relatively slower, meets its rate of change and is not higher than the response speed ceiling restriction of 10A/s.Supplementary energy Radio-frequency component in load energy demand is then provided.

Thus embodiment is visible, and the inventive method need not the model parameter to system in actual vehicular applications and carries out essence Really identification, can carry out more accurate regulation and control and the reasonable distribution of power, meet it immesurable supplementary energy SOC The dynamic response of power output limits, and reduces and realizes difficulty, improves the robustness of system.

Claims (7)

1. the realtime power distribution control method of a vehicle-mounted hybrid power system, it is characterised in that:

1) key characterization parameter to hybrid power system uses adaptive updates rule to carry out On-line Estimation；

2) build virtual negative current-carrying online updating rule based on key characterization parameter estimated value, energy resource system is carried out real-time merit Rate is distributed.

The realtime power distribution control method of a kind of vehicle-mounted hybrid power system the most according to claim 1, its feature exists In: described key characterization parameter includes supplementary energy equivalent internal resistance and load equivalent resistance.

The realtime power distribution control method of a kind of vehicle-mounted hybrid power system the most according to claim 2, its feature exists In: described step 1) supplementary energy equivalent internal resistance specifically use adaptive updates rule estimate, so that auxiliary energy Source equivalent internal resistance estimated valueAt supplementary energy equivalent internal resistance actual value R_ijBound within the scope of, be:

$R_{0,\min }\≤{\hat{R}}_0\≤R_{0,\max }$

Wherein, upper bound R_{0, max}More than supplementary energy equivalent internal resistance actual value R_ijSupremum, lower bound R_{0, min}More than supplementary energy etc. Effect internal resistance actual value R_ijInfimum.

The realtime power distribution control method of a kind of vehicle-mounted hybrid power system the most according to claim 3, its feature exists In: described adaptive updates rule employing below equation:

Wherein, q₁Represent supplementary energy adaptive factor, c₁Represent supplementary energy intermediate variable, R_ijIn representing supplementary energy equivalence Resistance actual value,Represent supplementary energy equivalent internal resistance estimated value；γ₁It it is supplementary energy adaptive gain normal number；R_{0, max}With R_{0, min}Represent supplementary energy equivalent internal resistance R respectively_ijThe upper bound and lower bound；V is bus voltage,For supplementary energy open circuit electricity Pressure setting value；i_fFor auxiliary energy source electric current,Represent actual loading electric current i_lWith designed dummy load electric currentInclined Difference.

5. distribute control method according to the realtime power of a kind of vehicle-mounted hybrid power system described in claim 2, it is characterised in that: Described step 1) specifically:

1.1) being obtained load equivalent resistance by the method estimating load equivalent conductance, load equivalent conductance uses self adaptation More new law is estimated, so that load equivalent conductance estimated valueAt load equivalent conductance actual value G_lBound scope Within, it is:

$G_{l,\min }\≤{\hat{G}}_l\≤G_{l,\max }$

Wherein, upper bound G_{L, max}With lower bound G_{L, min}It is by load equivalent resistance actual value R_lBound determine, meet:

$G_{l,\max }-\frac{1}{R_{l,\min }},G_{l,\min }-\frac{1}{R_{l,\max }}$

Wherein, R_{L, max}With R_{L, min}Represent load equivalent resistance actual value R respectively_lSupremum and infimum；

1.2) equivalent conductance estimated value is being obtainedAfter, utilize formulaIt is calculated load equivalent resistance estimated value

The realtime power distribution control method of a kind of vehicle-mounted hybrid power system the most according to claim 5, its feature exists In: described adaptive updates rule employing below equation:

Wherein, q₂Represent the loaded self-adaptive factor, c₂Represent load intermediate variable, G_lFor load equivalent conductance actual value, R_lIt is negative Carry equivalent resistance actual value,For load equivalent conductance estimated value；γ₂It it is loaded self-adaptive gain normal number；Represent virtual Load current；G_{L, max}With G_{L, min}It is to be load equivalent conductance actual value G respectively_lThe upper bound and lower bound；Represent actual loading electricity Stream i_lWith designed dummy load electric currentDeviation.

7. distribute control method according to the realtime power of a kind of vehicle-mounted hybrid power system described in claim 2, it is characterised in that: Described step 2) specifically:

2.1) the online updating rule using below equation to represent calculates and obtains dummy load electric current

Wherein, α₁Represent load tracking gain constant, α₂Represent supplementary energy state-of-charge (SOC) regulation storage gain constant；

2.2) use below equation to calculate and obtain main source of energy output current design value

Wherein, β represents that supplementary energy SOC regulates proportional gain constant.