CN103944476A - Torque controller of electric vehicle - Google Patents

Abstract

The invention discloses a torque controller of an electric vehicle. A PI torque controller is combined with a sliding-mode torque controller, a switch module weights a torque current obtained by the PI torque controller and a torque current obtained by the sliding-mode torque controller through different weight coefficients according to a motor speed error to obtain given torque currents, when the motor speed error |delta omega [r] | is larger than or equal to delta omega [r] max, the torque current is completely provided by the sliding-mode torque controller to improve following performance of the rotating speed; when the motor speed error |delta omega [r]| is smaller than delta omega [r] min, the torque current is provided by the PI torque controller, so that floating tracking of the given rotating speed is ensured; when the motor speed error |delta omega [r] | is larger than the delta omega [r] min and smaller than the delta omega [r] max, the two torque controllers operate at the same time so that smooth transition can be ensured. According to the torque controller of the electric vehicle, due to the fact that the PI torque controller is combined with the sliding-mode torque controller, control rapidity is improved, the magnitude of shakes of sliding mode control can be reduced, the rapid following performance of control over an induction motor is improved, and stability of rotating speed control is improved.

Description

A kind of electric automobile torque controller

Technical field

The invention belongs to motor in electric automobile control technology field, more specifically say, relate to a kind of electric automobile torque controller.

Background technology

Along with becoming increasingly conspicuous of the problems such as social development and the energy, environmental protection, pure electric automobile is with its zero discharge, low noise advantages is more and more subject to the attention of countries in the world, and electric automobile has become the developing direction of 21 century automobile industry, is one of topmost developing direction of Green Vehicle.Drive motors and motor drive controller be as the pith of " three horizontal strokes " technology, and what be to provide that electric automobile drives power directly provides mechanism, and the quality of its drive characteristic has directly determined the quality of electric automobile during traveling performance.General traditional PI torque controller and the synovial membrane torque controller adopting of torque controller in conventional electric automotive control system.

Fig. 1 is a kind of drive system of electric automobile theory diagram based on PI torque controller.As shown in Figure 1, PI(Proportional Integral, proportional integral) torque controller 12 is according to the given rotating speed of gas pedal 11 the actual speed ω feeding back with motor 17 _rgenerate given torque current i _sq, its dominated formulate is:

i _sq(t)＝K _pe(t)+K _i∫e(t)dt

Wherein, K _p, K _ibe respectively proportionality coefficient and the integral coefficient of PI torque controller; E (t) is error originated from input, $e\left(t\right)={\mathrm{\ω}}_r^{*}\left(t\right)-{\mathrm{\ω}}_r\left(t\right).$

PI torque controller 12 provides given torque current i _sq ^*give indirect vector control module 16, this drive system of electric automobile adopts weak magnetic controller 13 that given exciting current i is provided _sd ^*give indirect vector control module 16, vector control module 16 generates SVPWM (Space Vector Pulse Width Modulation indirectly, space vector pulse width modulation) ripple carrys out power ratio control module 15 six road IGBT(Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) time that turns on and off of power tube controls the actual speed that motor 17 is exported indirectly, and 3/2 conversion module 14 is the three-phase current i of the motors 17 that collect _a, i _b, i _cconvert the required exciting current i of indirect vector control module 16 to _sdwith torque current i _sqclosed-loop control in addition.

Although PI torque controller algorithm is simple, practical, but PI torque controller has intrinsic shortcoming: and the PI parameter for same control system different rotating speeds is changeless, thereby can cause rotating speed response slow, speed overshoot amount is large, PI difficult parameters with regulate etc.

Fig. 2 is the example theory diagram of a kind of drive system of electric automobile based on synovial membrane torque controller.As shown in Figure 2, the same with PI torque controller 12, synovial membrane torque controller 22 is according to the given rotating speed of gas pedal 21 the actual speed ω feeding back with motor 27 _rgenerate given torque current i _sq, its dominated formulate is:

i _sq(t)＝-kx(t)-βsgn(x(t))

$\mathrm{sgn}\left(x\left(t\right)\right)=\left\{\begin{array}{c}1,\left(x\left(t\right)\right)>0\\ -1,\left(x\left(t\right)\right)<0\end{array}\right.$

$\left\{\begin{array}{c}k>0\\ \mathrm{\&beta;}>\frac{L_r{T}_l}{{\mathrm{PL}}_m^2{i}_{\mathrm{sd}}^{\&prime;}}>0\end{array}\right.$

Wherein, k, β are the setting coefficient of synovial membrane controller, can be by the convergence rate of coefficient k, β adjustment synovial membrane controller is set.X (t) is given rotating speed with actual speed ω _r(t) error, L _rfor the rotor self-induction of motor 27, T _lfor the maximum load torque that motor 27 can bear, P is the number of pole-pairs of motor 27, L _mfor the mutual inductance of motor 27, i ' _sdfor the rated exciting current of motor 27.

Same, synovial membrane torque controller 22 provides given torque current i _sq ^*give indirect vector control module 26, adopt weak magnetic controller 23 that given exciting current i is provided _sd ^*give indirect vector control module 26, indirectly vector control module 26 generates the time that turns on and off that SVPWM ripple carrys out power ratio control module 25 six road IGBT power tubes and indirectly controls the actual speed that motor 27 is exported, and 3/2 conversion module 24 is the three-phase current i of the motors 27 that collect _a, i _b, i _cconvert the required exciting current i of indirect vector control module 26 to _sdwith torque current i _sqclosed-loop control in addition.

Synovial membrane torque controller has that algorithm is simple, fast response time, to external world noise jamming and Parameter Perturbation there is robustness, without advantages such as system on-line identification, physics realization are simple.But the intrinsic defect of synovial membrane torque controller itself is system and can trembles up and down shake at synovial membrane face and make motor actual speed to fluctuate up and down and then to affect its controller at given rotating speed normally to move.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of electric automobile torque controller is provided, combine and use PI torque controller and synovial membrane torque controller, improve the quick followability of speed and the stability of drive system of electric automobile.

For achieving the above object, electric automobile torque controller of the present invention, comprises PI torque controller, synovial membrane torque controller, switching over module, wherein:

PI torque controller receives the given rotating speed ω from electric automobile pedal _r ^*actual speed ω with motor in electric automobile _r, generate torque current i _sq1 ^*input switch handover module;

Synovial membrane torque controller receives the given rotating speed ω from the electric automobile pedal of gas pedal _r ^*actual speed ω with motor in electric automobile _r, generate torque current i _sq2 ^*input switch handover module;

Switching over module receives the given rotating speed ω from gas pedal _r ^*actual speed ω with motor _r, and the torque current i of PI torque controller and the generation of synovial membrane torque controller _sq1 ^*and i _sq2 ^*, obtain torque current i _sq ^*:

i _sq ^*＝λ*i _sq1 ^*+(1-λ)*i _sq2 ^*

Wherein, λ is weighting parameter, and the method for determining is:

$\left\{\begin{array}{c}\mathrm{\&lambda;}=1,\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\&le;\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min \\ \mathrm{\&lambda;}=1-\frac{\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|-\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min }{\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max -\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min },\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min <\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|<\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \\ \mathrm{\&lambda;}=0,\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \&le;\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\end{array}\right.$

Wherein, Δ ω _r=ω _r-ω _r ^*, Δ ω _rmin represents slow-speed of revolution error point, Δ ω _rmax represents high speed error point.

Electric automobile torque controller of the present invention, by PI torque controller and the combination of synovial membrane torque controller, torque current PI torque controller and synovial membrane torque controller being obtained respectively with different weights coefficients according to motor revolution error by switching over module is weighted and obtains given torque current.Work as motor revolution error | Δ ω _r|>=Δ ω _rwhen max, provide torque current to carry out pick up speed followability completely by synovial membrane torque controller.Work as motor revolution error | Δ ω _r|≤Δ ω _rwhen min, provide with this and carry out the astatic tracing preset speed of guarantee speed by PI torque controller.As motor revolution error Δ ω _rmin < | Δ ω _r| < Δ ω _rwhen max, two kinds of torque controllers move simultaneously and ensure to seamlessly transit.Adopt in this way, can ensure that the rapidity of controlling also can weaken synovial membrane control shake, increase the quick followability of induction machine rotating speed control, improved the stability of rotating speed control.

Brief description of the drawings

Fig. 1 is a kind of drive system of electric automobile theory diagram based on PI torque controller;

Fig. 2 is a kind of drive system of electric automobile theory diagram based on synovial membrane torque controller;

Fig. 3 is a kind of embodiment theory diagram of the drive system of electric automobile based on electric automobile torque controller of the present invention;

Fig. 4 is the function curve of weighting parameter λ;

Fig. 5 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the driving of PI torque controller;

Fig. 6 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the driving of synovial membrane torque controller;

Fig. 7 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the present invention's driving.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described, so that those skilled in the art understands the present invention better.Requiring particular attention is that, in the following description, in the time that perhaps the detailed description of known function and design can desalinate main contents of the present invention, these are described in here and will be left in the basket.

Embodiment

Fig. 3 is a kind of embodiment theory diagram of the drive system of electric automobile based on electric automobile torque controller of the present invention.As shown in Figure 3, electric automobile torque controller 32 of the present invention comprises PI torque controller 321, synovial membrane torque controller 322, switching over module 323.

PI torque controller 321 receives the given rotating speed ω from electric automobile pedal 31 _r ^*actual speed ω with motor in electric automobile 37 _r, generate torque current i _sq1 ^*input switch handover module 323.

The same with PI torque controller 321, synovial membrane torque controller 322 receives the given rotating speed ω from the electric automobile pedal of gas pedal _r ^*actual speed ω with motor in electric automobile _r, generate torque current i _sq2 ^*input switch handover module 323.

In the present invention, PI torque controller 321 and synovial membrane torque controller 322 generate respectively torque current according to torque control mode separately, but these two torque currents are not the follow-up indirect vector control module 36 of directly input, but first input to switching over module 323, obtain final given torque current by switching over module 323.

Switching over module 323 receives the given rotating speed ω from gas pedal 31 _r ^*actual speed ω with motor _r, and the torque current i that generates of PI torque controller 321 and synovial membrane torque controller 322 _sq1 ^*and i _sq2 ^*, obtain given torque current i _sq ^*:

i _sq ^*＝λ*i _sq1 ^*+(1-λ)*i _sq2 ^*

Wherein, λ is weighting parameter.

Because synovial membrane torque controller has very fast response speed, PI torque controller can floating tracing preset speed, and in the present invention, switching over module 323 need to be according to motor revolution error Δ ω _rswitch different torque controllers and control corresponding given torque current i _sq ^*, to reach the object of accurate control motor speed.Motor revolution error Δ ω _r=ω _r-ω _r ^*.As motor revolution error Δ ω _r| Δ ω _r|>=Δ ω _r, provide given torque current i completely by synovial membrane torque controller 322 when in max the district _sq ^*accelerate followability, now weighting parameter λ=0; As motor revolution error Δ ω _r| Δ ω _r|≤Δ ω _rwhen in min the district, due to the intrinsic jittering characteristic tracing preset speed well of synovial membrane controller itself, therefore given torque current i now _sq ^*completely provide with this and come the astatic tracing preset speed of guarantee speed, now weighting parameter λ=1 by PI torque controller.Δ ω _rmin, Δ ω _rmax is the speed error switching point that the artificial torque controller arranging switches, Δ ω _rmin is slow-speed of revolution error point, Δ ω _rmax is high speed error point, be on the occasion of, according to actual conditions, value is set, generally 2 Δ ω _rmin≤Δ ω _rmax.

Because switching rule and the handoff procedure of torque controller are all realized by program in switching over module 323, so switching rule can design flexibly, consider stability when torque controller switches, the present invention adopts the method for variation weighting to realize the slow switching of two kinds of torque controllers.In handoff procedure, i.e. Δ ω _rmin < | Δ ω _r| < Δ ω _rmax, weighting parameter is:

$\mathrm{\&lambda;}=1-\frac{\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|-\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min }{\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max -\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min }$

In sum, in the present invention, definite method of weighting parameter λ is:

$\left\{\begin{array}{c}\mathrm{\&lambda;}=1,\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\&le;\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min \\ \mathrm{\&lambda;}=1-\frac{\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|-\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min }{\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max -\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min },\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min <\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|<\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \\ \mathrm{\&lambda;}=0,\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \&le;\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\end{array}\right.$

Visible, weighting parameter λ be one with motor revolution error Δ ω _rfor the piecewise function of variable.Fig. 4 is the function curve of weighting parameter λ.

With an example, beneficial effect of the present invention is described below.Respectively PI torque controller, synovial membrane torque controller and the present invention are applied to the Simulink Simulation drive system of 3KW induction machine being carried out to indirect vector control.Table 1 is the technical parameter of 3KW induction machine.

Rated voltage u n	380V
		Rated current i n	5.37A
Nominal torque T en	20.04N*m
		Rated power P n	3kW
Rated frequency f n	50Hz

Rated speed n n	1470rpm
		Moment of inertia J	0.018kg.m^2
Number of pole-pairs p	2
		Overload magnification	3
Leakage inductance Delta	0.0897
		Rotor mutual inductance Lm	0.187H
Rotor two phase winding self-induction Lr	0.196H
		Stator two phase winding self-induction Ls	0.196H
Rotor two-phase winding resistance Rr	1.45Ω
		Stator two-phase winding resistance Rs	1.898Ω
Time constant Tr	0.1352

Table 1

This emulation experiment is at induction machine torque at rated load 20.04N*m, and given rotating speed is to carry out under 10rad/s.

In PI torque controller, Proportional coefficient K _p=0.5, integral coefficient K _i=1.4.

In synovial membrane torque controller, calculate the span of undetermined coefficient k and β according to induction machine technical parameter, the maximum load torque T that wherein motor can bear _lshould be the nominal torque 20.04N*m that motor can provide:

$\left\{\begin{array}{c}k>0\\ \mathrm{\&beta;}>\frac{L_r{T}_l}{{\mathrm{PL}}_m^2{i}_{\mathrm{sd}}}=\frac{0.196*20.04}{0*{0.187}^2*6.0}=9.36\end{array}\right.$

In this emulation experiment, get k=0.4, β=9.4.And because synovial membrane control itself has buffeting characteristic, replace impair system to a great extent to buffet with continuous saturation function sat (x (t)) the sign function sgn in synovial membrane torque controller (x (t)).The saturation function adopting in this emulation experiment is as follows:

$\mathrm{sat}\left(x\left(t\right)\right)=\left\{\begin{array}{c}1,x\left(t\right)\&GreaterEqual;\frac{\mathrm{\&pi;}}{\sqrt{2}}\mathrm{\&epsiv;}\\ \sin \left(\frac{x\left(t\right)}{\sqrt{2}\mathrm{\&epsiv;}}\right),-\frac{\mathrm{\&pi;}}{\sqrt{2}}\mathrm{\&epsiv;}<x\left(t\right)<\frac{\mathrm{\&pi;}}{\sqrt{2}}\mathrm{\&epsiv;}\\ -1,x\left(t\right)\&le;-\frac{\mathrm{\&pi;}}{\sqrt{2}}\mathrm{\&epsiv;}\end{array}\right.$

ε is undetermined coefficient, in this emulation experiment, ε=1 is set.

The PI torque controller adopting in electric automobile torque controller of the present invention is identical with synovial membrane torque controller with the PI torque controller using separately with synovial membrane torque controller.Δ ω in this emulation experiment _rmin is set to 0.1rad/s, Δ ω _rmax is set to 1rad/s.

Fig. 5 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the driving of PI torque controller.Fig. 6 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the driving of synovial membrane torque controller.Fig. 7 is three-phase current, torque, the actual speed schematic diagram of the induction machine based on the present invention's driving.Fig. 5, Fig. 6, Fig. 7 are contrasted known, the performance of three kinds of torque controllers can reach good level, and three-phase current wave distortion is little, and the torque of output is also comparatively stable.But from rotating speed and followability aspect, PI torque controller needs 6s to reach given rotating speed, and torque controller of the present invention only needs 1.9s can reach given rotating speed.From eliminating static difference and weakening and tremble shake aspect, synovial membrane speed control is because existence is trembled shake and caused finally failing to be stabilized in given rotating speed, and torque controller of the present invention, owing to having the effect of PI link finally can be stabilized in given rotating speed and without trembling shake phenomenon.

Although above the illustrative embodiment of the present invention is described; so that those skilled in the art understand the present invention; but should be clear; the invention is not restricted to the scope of embodiment; to those skilled in the art; as long as various variations appended claim limit and definite the spirit and scope of the present invention in, these variations are apparent, all utilize innovation and creation that the present invention conceives all at the row of protection.

Claims (3)

1. an electric automobile torque controller, is characterized in that, comprises PI torque controller, synovial membrane torque controller, switching over module, wherein:

PI torque controller receives the given rotating speed ω from electric automobile pedal _r ^*actual speed ω with motor in electric automobile _r, generate torque current i _sq1 ^*input diverter switch handover module;

Synovial membrane torque controller receives the given rotating speed ω from the electric automobile pedal of gas pedal _r ^*actual speed ω with motor in electric automobile _r, generate torque current i _sq2 ^*input switch handover module;

Switching over module receives the given rotating speed ω from gas pedal _r ^*actual speed ω with motor _r, and the torque current i of PI torque controller and the generation of synovial membrane torque controller _sq1 ^*and i _sq2 ^*, obtain torque current i _sq ^*:

i _sq ^*＝λ*i _sq1 ^*+(1-λ)*i _sq2 ^*

Wherein, λ is weighting parameter, and the method for determining is:

$\left\{\begin{array}{c}\mathrm{\&lambda;}=1,\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\&le;\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min \\ \mathrm{\&lambda;}=1-\frac{\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|-\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min }{\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max -\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min },\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\min <\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|<\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \\ \mathrm{\&lambda;}=0,\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\max \&le;\left|\mathrm{\&Delta;}{\mathrm{\&omega;}}_r\right|\end{array}\right.$

Wherein, Δ ω _rmin represents slow-speed of revolution error point, Δ ω _rmax represents high speed error point.

2. electric vehicle controller according to claim 1, is characterized in that, described slow-speed of revolution error point Δ ω _rmin and high speed error point Δ ω _rmax meets 2 Δ ω _rmin≤Δ ω _rmax.

3. electric automobile torque controller according to claim 1, is characterized in that, the sign function in described synovial membrane torque controller adopts continuous saturation function.