阅读说明：本技术 一种复合式自由活塞直线发电机稳定工作的方法 (A kind of method of combined type free piston linear generator steady operation ) 是由 唐娟 程勇 吕宏 马宗正 于 2019-09-20 设计创作，主要内容包括：本发明实施例公开了一种复合式自由活塞直线发电机稳定工作的方法,所述复合式自由活塞发电机包括与发电机同轴连接的辅助电动机,所述方法包括启动时,计算活塞运动到下一上止点位置需要的拖动力,通过控制辅助电动机的输入电压满足所述拖动力的要求；运行过程中,确定活塞在到达下一上止点位置时需要的电能,控制发电机或辅助电机的输入电压,满足所述电能需求。本发明辅助电机的协助,可保证自由活塞直线发电机稳定运行,同时发电机只需负责发电,不需要进行发电和电动模式的转换,解决现有自由活塞直线发电机中发电机工作模式转换响应时间长得问题。(The embodiment of the invention discloses a kind of methods of combined type free piston linear generator steady operation, the combined type free-piston generator includes the auxiliary motor connecting with generator coaxle, the method includes when starting, the drawing force that piston motion is needed to next top dead center position is calculated, the input voltage by controlling auxiliary motor meets the requirement of the drawing force；In operational process, the electric energy that piston is needed when reaching next top dead center position is determined, control the input voltage of generator or stand-by motor, meet the electrical energy demands.The assistance of stand-by motor of the present invention, it can guarantee free piston linear generator stable operation, generator need to only be responsible for power generation simultaneously, do not need the conversion for carrying out power generation and electric model, solve the problems, such as that the generator operation mode transition response time grows in existing free piston linear generator.)

1. a kind of method of combined type free piston linear generator steady operation, characterized in that the combined type free-piston Generator includes the auxiliary motor connecting with generator coaxle, which comprises

When starting, the drawing force that piston motion is needed to next top dead center position is calculated, by the input for controlling auxiliary motor Voltage meets the requirement of the drawing force；

In operational process, the electric energy that piston is needed when reaching next top dead center position is determined, control generator or stand-by motor Input voltage, meet the electrical energy demands.

2. the method for combined type free piston linear generator steady operation according to claim 1, characterized in that described The drawing force that piston motion is needed to next top dead center position specifically:

In formula, P_Pressure=f (x) is the function about piston displacement x, and A indicates the forced area of piston, x_maxIndicate the effective row of piston The half of journey.

3. the method for combined type free piston linear generator steady operation according to claim 2, characterized in that described Input voltage by controlling auxiliary motor meets the requirement of the drawing force specifically:

According to drawing force, auxiliary motor is calculated under the effect of current drawing force, moves to next top dead center position work done；

Next top dead center position work done is moved to according to described, determines the input voltage of auxiliary motor, is controlled described defeated Enter voltage and meets acting requirement.

4. the method for combined type free piston linear generator steady operation according to claim 1, characterized in that described Peak acceleration or maximum speed that the electric energy that piston is needed when reaching next top dead center position is reached by piston determines.

5. the method for combined type free piston linear generator steady operation according to claim 4, characterized in that described The calculating of peak acceleration specifically:

Displacement acquisition point is respectively set in peak acceleration position and front and back, obtains at least three displacement and corresponding time, calculates Acceleration, as peak acceleration, the calculation formula of the peak acceleration are as follows:

In formula, S₁、t₁Indicate first measured displacement and corresponding time, S₂、t₂It indicates second measured displacement and corresponds to Time, S₃、t₃Indicate the third measured displacement and corresponding time.

6. the method for combined type free piston linear generator steady operation according to claim 5, characterized in that pass through Peak acceleration determines the electric energy needed when piston reaches next top dead center position specifically:

In formula, x_maxFor the half of piston effective travel, a_maxFor peak acceleration, x₁For the piston displacement at ignition location, v₁For When piston can reach at top dead centre, the minimum speed needed at ignition location, W_fFor frictional force work done, m is piston fortune The quality of moving part, p_{Press max}For the in-cylinder pressure at ignition location, d is piston diameter.

7. the method for combined type free piston linear generator steady operation according to claim 4, characterized in that described The calculating of maximum speed specifically:

In the forward and backward setting displacement acquisition point of maximum speed position, at least two displacement and corresponding time are obtained, calculating speed is made For maximum speed, the calculation formula of the maximum speed are as follows:

In formula, s '₁、t’₁Respectively indicate the first displacement measured and corresponding time, s'₂、t’₂Respectively indicate the second displacement measured With the corresponding time.

8. the method for combined type free piston linear generator steady operation according to claim 7, characterized in that pass through Maximum speed determines the electric energy needed when piston reaches next top dead center position specifically:

In formula, v_maxIndicate the maximum speed of piston motion, x₂Indicate piston motion corresponding displacement, p at maximum speed_vmaxTable Show piston motion corresponding in-cylinder pressure, x at maximum speed₁Indicate the piston displacement at ignition location, v₁It can reach for piston When at top dead centre, the minimum speed needed at ignition location, W_fFor frictional force work done, m is the quality of piston motion part, p_{Press max}For the in-cylinder pressure at ignition location, d is piston diameter.

9. the method for combined type free piston linear generator steady operation according to claim 6 or 8, characterized in that The input voltage of the control generator or stand-by motor, meets the detailed process of the electrical energy demands are as follows:

Judge the piston when reaching next top dead center position required electric energy it is positive and negative；

If nonnegative value, then by the input voltage of control generator, meet the electrical energy demands；

If negative value, then generator stops working, auxiliary motor work, and the input voltage for controlling auxiliary motor generates drive Power meets the electrical energy demands.

Technical field

The present invention relates to extended range device of new energy automobile technical field, specifically a kind of combined type free piston linear hair The method of motor stabilizing work.

Background technique

Free piston linear generator (FPLG, free-piston linear generator) structure master common at present To include motor and engine two parts, be divided into single-piston formula, opposed dual-active again according to the arrangement and number of motor and engine Plug (abbreviation opposed type) and back set three kinds of dual Piston (abbreviation back-positioned type).Since FPLG reduces crank link mechanism, because This, the thermal efficiency is compared with traditional combustion engine height, with good application prospect.

For PFLG in start-up course, motor is as electric motor operation and provides power, dragging piston motion to designated position, hair Motivation ignition exports electric energy, into course of normal operation at this point, motor is converted to generator mode from electric motor mode.

Due to the Combustion Cycle Variability of engine, the position that piston reaches top dead centre every time can all generate difference, if compression Than deficiency, it may cause that in-cylinder combustion situation is very poor possibly even to catch fire, at this point, the power only generated by compressed gas, piston Electromagnetic resistance can not be overcome smoothly to move to next designated position, and then shut down.Control strategy common at present is, once prison It measures engine fire or burning is very poor, generator is converted into motor, dragging piston reaches designated position.But this method is deposited Long in motor work conversion time, motor generates power and is also required to regular hour response, therefore, still can generate FPLG fortune Row is unstable, the problem of can not continuing working for a long time.

Summary of the invention

A kind of method of combined type free piston linear generator steady operation is provided in the embodiment of the present invention, to solve Generator is converted into the response time length of motor in the prior art, causes the problem of FPLG fluctuation of service.

In order to solve the above-mentioned technical problem, the embodiment of the invention discloses following technical solutions:

The present invention provides a kind of method of combined type free piston linear generator steady operation, the combined type is free Piston generator includes the auxiliary motor connecting with generator coaxle, which comprises

When starting, the drawing force that piston motion is needed to next top dead center position is calculated, passes through control auxiliary motor Input voltage meets the requirement of the drawing force；

In operational process, the electric energy that piston is needed when reaching next top dead center position is determined, control generator or auxiliary The input voltage of motor meets the electrical energy demands.

Further, the drawing force that the piston motion is needed to next top dead center position specifically:

In formula, P_Pressure=f (x) is the function about piston displacement x, and A indicates the forced area of piston, x_maxIndicate that piston has Imitate the half of stroke.

Further, the input voltage by controlling auxiliary motor meets the requirement of the drawing force specifically:

According to drawing force, auxiliary motor is calculated under the effect of current drawing force, next top dead center position is moved to and is done Function；

Next top dead center position work done is moved to according to described, determines the input voltage of auxiliary motor, controls institute It states input voltage and meets acting requirement.

Further, the electric energy that the piston is needed when reaching next top dead center position by piston reach most greatly Speed or maximum speed determine.

Further, the calculating of the peak acceleration specifically:

Displacement acquisition point is respectively set in peak acceleration position and front and back, obtains at least three displacement and corresponding time, Calculate acceleration, as peak acceleration, the calculation formula of the peak acceleration are as follows:

In formula, S₁、t₁Indicate first measured displacement and corresponding time, S₂、t₂Indicate measure second displacement and Corresponding time, S₃、t₃Indicate the third measured displacement and corresponding time.

Further, the electric energy needed when determining that piston reaches next top dead center position by peak acceleration specifically:

In formula, x_maxFor the half of piston effective travel, a_maxFor peak acceleration, x₁For the piston position at ignition location It moves, v₁When can reach at top dead centre for piston, the minimum speed needed at ignition location, W_fFor frictional force work done, m is The quality of piston motion part, p_{Press max}For the in-cylinder pressure at ignition location, d is piston diameter.

Further, the calculating of the maximum speed specifically:

In the forward and backward setting displacement acquisition point of maximum speed position, at least two displacement and corresponding time are obtained, speed is calculated Degree, as maximum speed, the calculation formula of the maximum speed are as follows:

In formula, s₁'、t₁' respectively indicate the first displacement measured and corresponding time, s'₂、t₂' respectively indicate second measured Displacement and corresponding time.

Further, the electric energy needed when determining that piston reaches next top dead center position by maximum speed specifically:

In formula, v_maxIndicate the maximum speed of piston motion, x₂Indicate piston motion corresponding displacement at maximum speed, p_vmaxIndicate piston motion corresponding in-cylinder pressure, x at maximum speed₁Indicate the piston displacement at ignition location, v₁For piston When can reach at top dead centre, the minimum speed needed at ignition location, W_fFor frictional force work done, m is piston motion part Quality, p_{Press max}For the in-cylinder pressure at ignition location, d is piston diameter.

Further, the input voltage of the control generator or stand-by motor, meets the specific mistake of the electrical energy demands Journey are as follows:

Judge the piston when reaching next top dead center position required electric energy it is positive and negative；

If nonnegative value, then by the input voltage of control generator, meet the electrical energy demands；

If negative value, then generator stops working, auxiliary motor work, and the input voltage for controlling auxiliary motor produces Raw driving force, meets the electrical energy demands.

Detailed description of the invention

In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technical description to be briefly described, it should be apparent that, for those of ordinary skill in the art Speech, without creative efforts, is also possible to obtain other drawings based on these drawings.

Fig. 1 is the structural schematic diagram of combined type free piston linear generator of the present invention；

Fig. 2 is the flow diagram of the method for the invention；

Fig. 3 is the distribution schematic diagram of displacement acquisition point of the present invention.

In figure, 1 generator, 11 generator unit stators, 12 generator rotors, 2 auxiliary motors, 21 auxiliary electric machine stators, 22 auxiliary motor movers, 3 pistons, 4 magnetic induction sensors, 41 magnetic railings rulers, 42 magnetic heads.

Specific embodiment

In order to clarify the technical characteristics of the invention, below by specific embodiment, and its attached drawing is combined, to this hair It is bright to be described in detail.Following disclosure provides many different embodiments or example is used to realize different knots of the invention Structure.In order to simplify disclosure of the invention, hereinafter the component of specific examples and setting are described.In addition, the present invention can be with Repeat reference numerals and/or letter in different examples.This repetition is that for purposes of simplicity and clarity, itself is not indicated Relationship between various embodiments and/or setting is discussed.It should be noted that illustrated component is not necessarily to scale in the accompanying drawings It draws.Present invention omits the descriptions to known assemblies and treatment technology and process to avoid the present invention is unnecessarily limiting.

As shown in Figure 1, increasing auxiliary motor 2, the hair of auxiliary motor 2 and existing FPLG on the basis of existing FPLG Motor 1 is coaxially connected, and auxiliary electric machine stator 21 and motor stator 11 connect, auxiliary motor mover 22 and generator unit stator 12 connections, realize the coaxial series connection of the two.Auxiliary motor 2 cooperates generator 1 to work, catch fire in start-up course and occurring or In the case that combustion position is very poor, auxiliary motor 2 generates power, and auxiliary piston 3 reaches designated position, and generator 1 is not required to The conversion of the mode of progress, is only used as generator, this can solve the problems, such as that original FPLG electrical machine working mode conversion time is growed, Meanwhile on the basis of this combined type free piston linear generator structure, in order to solve, piston top dead center is unstable to be asked Topic, the present invention propose the method that every circulating generator output electric energy is adjusted according to piston motion maximum speed or peak acceleration, Realize the stabilization of piston top dead center.

As shown in Fig. 2, the method for steady operation of the invention includes:

S1 when starting, calculates the drawing force that piston motion is needed to next top dead center position, passes through control auxiliary motor Input voltage meet the requirement of the drawing force；

S2 in operational process, determines the electric energy that piston is needed when reaching next top dead center position, controls generator or auxiliary The input voltage for helping motor meets the electrical energy demands.

In step S1, in start-up course, auxiliary motor drags piston motion to top dead center position, in order to guarantee first Working cycles can be realized piston motion and reach next top dead center position, the drawing force that required auxiliary motor provides are as follows:

(1) in formula, p_Pressure=f (x) is the function about piston displacement x, p_PressureIndicate the in-cylinder pressure in compression process, the power It is related with piston displacement x, but in one timing of engine, p_PressureThe functional relation of=f (x) can determine；The stress surface of A expression piston Product is constant；x_maxIt indicates the half of piston effective travel, is constant.

It according to the drawing force F that (1) formula calculates, is integrated, is obtained in the case where current drawing force is acted on by being displaced to piston motion, Next top dead center position work done W is moved to, according to formula W=UIt, and the mechanical efficiency of auxiliary motor is combined, true It fixes time in the case where t, by controlling input voltage, meets the requirement of above-mentioned drawing force, to guarantee that FPLG's stablizes starting.

In start-up course, as long as guaranteeing that piston reaches ignition location, engine controller issues firing command, and engine is just Ignition can be achieved.

The peak acceleration that the electric energy that piston is needed when reaching next top dead center position in step S2 is reached by piston Or maximum speed determines.

The detailed process of required electric energy is calculated using peak acceleration are as follows:

As shown in figure 3, displacement acquisition point, i.e. Fig. 2 are arranged before and after the peak acceleration appearance position and the position at 1mm Shown displacement acquisition point A1, displacement acquisition point A2 and displacement acquisition point A3 arrange 3 displacement acquisition points altogether, and obtain live respectively Plug passes through the time of three displacement acquisition points, calculates the peak acceleration of piston motion are as follows:

(2) in formula, S₁、t₁Indicate first displacement and corresponding time that first displacement acquisition point A1 is measured, S₂、t₂ Indicate second displacement and corresponding time that displacement acquisition point 2 measures, S₃、t₃Indicate the third position that displacement acquisition point 3 measures It moves and the corresponding time.Above-mentioned displacement acquisition point is illustrated by taking left hand cylinder as an example, the corresponding displacement acquisition of right cylinder Point B1, B2 and B3 and A1, A2 and A3 are corresponding in turn to.

It can wherein be respectively arranged the acquisition that displacement sensor carries out displacement data at displacement acquisition point, need corresponding cloth set Displacement sensor, as shown in Figure 1,1 magnetic induction sensor 4 can also be arranged, the magnetic railings ruler 41 of magnetic induction sensor 4 is mounted on mover axis On, magnetic head 42 is fixed on casing, and mover drives magnetic railings ruler 41 mobile, and magnetic head 42 reads magnetic grid position signal and is sent to control Device, so that controller realization accurately controls rotor position.More accurate maximum acceleration value in order to obtain, settable multiple positions Collection point is moved, is maximized as peak acceleration.

Determine the electricity that piston is needed when reaching next top dead center position specifically:

(3) in formula, x_maxIt is constant for the half of piston effective travel；x₁It is normal for the piston displacement at ignition location Number；v₁When can reach at top dead centre for piston, the minimum speed needed at ignition location can be obtained by testing or simulating, For constant；W_fIt for frictional force work done, can be measured by simulating or testing, be constant；

k_eqFor the equivalent stiffness of gas in the jar at top dead centre, expression formula are as follows:

(4) in formula, m is the quality of piston motion part, is constant；

k₁It is located at the equivalent stiffness of gas in the jar at ignition location for piston, expression is are as follows:

(5) in formula, P_{Press max}It for the in-cylinder pressure at ignition location, can be measured by testing or simulating, be constant；D is to live Diameter is filled in, is constant.

The relationship of peak acceleration Yu required electric energy is obtained based on above formula (3)-(5) are as follows:

The relationship for establishing piston required electric energy and peak acceleration when reaching next top dead center position, is obtaining maximum Acceleration a_maxAfterwards, corresponding electricity W can be obtained, according to the relationship of electricity and input voltage and working efficiency, control can be passed through Input voltage processed meets the requirement of electricity W.

The detailed process of required electric energy is calculated using maximum speed are as follows:

As shown in figure 3, being respectively set at least two displacement acquisitions point A4, A5 maximum speed position is forward and backward, obtain at least 2 displacements and corresponding time, calculating speed, as maximum speed, the calculation formula of maximum speed are as follows:

(7) in formula, s₁'、t₁' respectively indicate the first displacement measured and corresponding time, s'₂、t₂' respectively indicate and measure Second displacement and corresponding time.

The electric energy needed when determining that piston reaches next top dead center position by maximum speed specifically:

(8) formula establishes the relationship of maximum speed and required electric energy, wherein v_maxIndicate the maximum speed of piston motion, x₂ Indicate piston motion corresponding displacement, p at maximum speed_vmaxIndicate piston motion corresponding cylinder internal pressure at maximum speed Power, x₁Indicate the piston displacement at ignition location, v₁When can reach at top dead centre for piston, the minimum that is needed at ignition location Speed, W_fFor frictional force work done, m is the quality of piston motion part, p_{Press max}For the in-cylinder pressure at ignition location, d is to live Fill in diameter.

Obtaining maximum speed v_maxAfterwards, corresponding electricity W can be obtained, according to electricity and input voltage and working efficiency Relationship, can by control input voltage, meet the requirement of electricity W.

After obtaining W according to formula (6) or (8), it is positive and negative to first determine whether W's, if W is non-negative, representing generator should be issued Corresponding electric energy, controller adjust generator and export the corresponding electric energy of W by adjusting generator relevant parameter.If W is negative, show The energy that burning generates is insufficient to allow piston to run to other side top dead centre, at this point, controller control generator stops working, and Auxiliary motor work, and the corresponding electric energy of W is provided, dragging piston to designated position.

For back-positioned type FPLG, each cycle engine burning twice, will appear 2 speed during reciprocating motion of the pistons Peak value and 2 acceleration peak values, each circulation adjust generator input voltage twice.For single-piston formula FPLG and opposed type The stable operation that aforesaid way reaches FPLG equally can be used in FPLG.

The above is the preferred embodiment of the present invention, for those skilled in the art, In Without departing from the principles of the invention, several improvements and modifications can also be made, these improvements and modifications are also regarded as this hair Bright protection scope.