Disclosure of Invention
Aiming at the problem that the traditional IFT algorithm is difficult to meet the requirement of the parameter optimization of the position ring PI controller of the permanent magnet synchronous motor, the application provides the iterative feedback setting control and the optimization method of the permanent magnet synchronous motor, which integrates a new IFT framework, popularizes and applies the dual-cycle IFT algorithm to the setting and control performance optimization of the position ring PI controller parameters, and aims to improve the rapid and accurate tracking capability of the permanent magnet synchronous motor.
The technical scheme of the invention is as follows:
a permanent magnet synchronous motor iteration feedback setting control and optimization method comprises the following steps:
firstly, constructing a kinematics equation and a vector control system of the permanent magnet synchronous motor;
secondly, designing a position loop PI controller of a permanent magnet synchronous motor servo system based on a double-loop iterative feedback setting algorithm;
thirdly, analyzing the convergence and the convergence speed of the double-loop iterative feedback setting algorithm;
step four, specific implementation of a double-loop iteration feedback setting control scheme of the position ring is given;
firstly, constructing a kinematics equation and a vector control system of the permanent magnet synchronous motor:
on the premise of ignoring harmonic, hysteresis and eddy current loss, a stator voltage equation of the permanent magnet synchronous motor under a synchronous rotation coordinate system d-q is shown as a formula (1):
in the formula ud、uqD-q axis components, i, of stator voltage vectors, respectivelyd、iqD-q axis components of stator current vector, R stator resistance,. psid、ψqD-q axis components, ω, of stator flux linkage vectors, respectivelycIs the electrical angular velocity; further obtaining a stator flux linkage equation as follows:
wherein L isd、LqRespectively d-q axis inductance component,. psifRepresents a permanent magnet flux linkage; the stator voltage equation obtained by substituting formula (2) into formula (1) is:
according to the electromechanical transformation principle, the electromagnetic torque T is the partial derivative of magnetic field energy storage to mechanical angular displacement, and the electromagnetic torque equation of the permanent magnet synchronous motor is as follows:
wherein p isnIs a permanent magnetThe number of pole pairs of the step motor; further obtaining a kinematic equation of the permanent magnet synchronous motor as follows:
wherein ω ismIs the mechanical angular velocity of the permanent magnet synchronous motor, J is the rotational inertia, B is the damping coefficient, TLIs the load torque;
the vector control system of the permanent magnet synchronous motor is a three-closed-loop structure formed by a position loop, a speed loop and a current loop, and a PI (proportional integral) controller of the position loop performs parameter setting by using a double-loop iterative feedback setting algorithm according to input and output data and a tracking error of the vector control system;
secondly, designing a position loop PI controller of a permanent magnet synchronous motor servo system based on a double-loop iterative feedback setting algorithm:
designing a PI controller of a position ring aiming at a vector control system position ring of a permanent magnet synchronous motor, optimizing parameters by using a double-loop iterative feedback setting algorithm, and designing a PI controller C (z) of the position ring-1ρ) can be linearized as:
wherein the controller parameter ρ ═ K
p,K
I]
TLinear coefficient of controller
K
p、K
IProportional and integral coefficients, T, of PI controllers
sIs the sampling time; let S (z)
-1,ρ)=(P(z
-1)C(z
-1,ρ)+1)
-1, T(z
-1,ρ)=P(z
-1)S(z
-1,ρ),P(z
-1) A position ring model of the permanent magnet synchronous motor; if r is the system input and v is white noise with zero mean, the tracking error e of the position loop can be obtained as follows:
e=S(z-1)(1-P(z-1))r-S(z-1)v (7)
the mathematical model of the speed loop of the permanent magnet synchronous motor can be considered as a typical second-order system, and for a finite-time input linear constant system, the initial state can be expressed as follows:
in the formula (8), u and y are input and output respectively, n is the number of sampling points,
is formed by an impulse response coefficient h
s(s ═ 1,2,3 …) of Toeplitz subspace matrix, h
iAdding unit pulse excitation in a closed-loop state to obtain the product;
to improve the tracking effect of the position loop, the performance criterion function J (ρ) is not defined as:
J(ρ)=eQeT(9)
n is the total number of sampling points, and e is a tracking error matrix of the position loop; l isyIs a filter, usually L y1, Q is a unit array; minimizing a performance criterion function J (rho) by a dual-loop iterative feedback setting algorithm for finding an optimal parameter rho for a PI controller for a position loop*To thereby obtain an optimum control effect with respect to the acquisition of ρ*In the conventional iterative feedback setting IFT algorithm, a Gauss-Newton algorithm is usually used to calculate an update value of the next iteration:
wherein gamma is
i>0 represents a step size; r
iTo determine the Hessian matrix representation to optimize the search direction,
is the partial derivative of J (p) with respect to the controller parameter p, R
iAnd
unbiased estimation is usually done from a cubic reference input to the vector control system;
to simplify the writing, C of the ith iteration is
i(z
-1,ρ)、S
i(z
-1ρ) and T
i(z
-1ρ) is represented by C
i、S
iAnd T
iAddition of P (z)
-1) Corresponding to a Toeplitz matrix of
And
if ρ
i+1=ρ
i+Δρ
i+1I.e. knowing the controller parameter at the i-th iteration as ρ
i,Δρ
i+1Is rho
iTo the optimal controller parameter p
*Difference Δ ρ of
i+1 *J (Δ ρ)
i+1) Is zero, i.e.:
the error e of the ith iteration is obtained from equation (7)iError e from i +1 th iterationi+1The relationship of (1) is:
where P is a discrete function of the control object, ejIs the tracking error matrix at the jth iteration, then:
J(Δρi+1)=ei TQei-2ei TQf(Δρi+1)+fT(Δρi+1)Qf(Δρi+1) (13)
wherein:
at the (i + 1) th iteration,α
jis α
j(z
-1) The corresponding Toeplitz matrix is then used,
for the jth parameter Δ ρ
i+1,j、
Sum of products of:
J(Δρi+1) The gradient of (c) can then be derived from equation (11):
to obtain J (Δ ρ)i+1) Δ ρ when the gradient of (b) is zeroi+1 *And (3) defining an iterative loop again by using a simple iteration method, wherein the iteration number is represented by k, and the formula (15) is substituted into the formula (16) to obtain:
wherein:
if it is
Then the following results are obtained:
formula (19) substitutes for formula (17) and makes it zero:
from S (z)
-1,ρ)=(P(z
-1)C(z
-1,ρ)+1)
-1To obtain
And order:
then equation (20) can be:
definition of
Comprises the following steps:
can further obtain:
in the following to
And calculating to obtain the following principle by a tracking matrix inversion principle:
by substituting formula (25) for formula (23):
then calculate
According to formula (12)) Obtaining:
and because the matrix M exists
Further obtaining:
finally, the following can be obtained:
the calculation needs to be acquired through one impulse response experiment
Let r be 0, u be the unit pulse input, v be white noise with mean zero, get the impulse response sequence ζ
TAnd ζ
STo establish a relation with S
iAnd T
iToeplitz matrix of
Thirdly, analyzing the convergence and the convergence speed of the double-loop iterative feedback setting algorithm:
the next iteration update value is typically calculated using the Gauss-Newton algorithm:
wherein R is
iIs a matrix, γ
iIs a scalar quantity when
And 0<γ
iAt most 1, rho
iUsually linearly converging, in which caseThere are:
||ρi+1-ρ*||≤||ρi-ρ*|| (31)
gradient is known
The method comprises the following steps:
subtracting (17) from equation (32) yields:
is defined by the formula (21), known as
Is formed by
As obtained, equation (33) can further obtain:
conform to
And 0<γ
iA convergence condition of ≦ 1, so that the two-loop iterative feedback setting algorithm is convergent, further considering the convergence rate of the algorithm, according to equation (22) inner loop and
then, the first iteration is
At a very small time, the device is,having the formula:
wherein 0< β < 1;
theorem 2: assuming that the iteration number of the internal loop is m, | | ρi-ρ*When | | is smaller, the algorithm m-th order converges,
and (3) proving that: through formula (35) and
it is possible to obtain:
and is
Then finally it can be found:
||Δρi+1-ρ*||≤βm||ρi-Δρ*|| (37)
theorem 2 shows that the dual-loop iterative algorithm is m-order convergent, so that the convergence rate is higher than that of the traditional IFT algorithm;
step four, specific implementation of a double-loop iteration feedback setting control scheme of the position ring is given:
the double-loop iterative feedback setting track tracking control method for the position ring of the permanent magnet synchronous motor servo system has the following specific scheme:
1) aiming at a permanent magnet synchronous motor servo system, setting a position signal to be r-30 degrees, enabling the motor to run in a no-load mode, and influenced by white noise v with zero mean value in the working process, wherein the sampling time T is 1 multiplied by 10-4s, in order to further reduce overshoot in the simulation, e is counted from the 50 th sampling point;
2) given initial controller parameter ρ1Establishing a criterion function J (rho) according to equation (7)i) Making an outer loop iteration coefficient i equal to 1;
3) carrying out internal circulation acquisition:
step 1: toeplitz matrix obtained by impulse response experiment
And 2, step 2: given a
e
iAnd ρ
iLet the internal circulation coefficient k equal to 1
And 3, step 3: k iterations through equations (20), (21), (26) and (29) are obtained
Namely, it is
4) Calculating rhoi+1=ρi+Δρi+1 *;
5) To obtain rhoi+1Then, J (ρ) is further calculated according to a criterion functioni+1) If the control requirement is met, turning to the step 6, otherwise, turning to the step 3;
6) and (6) ending.
The beneficial technical effects of the invention are as follows:
the method is characterized in that industrial equipment such as PMSM (permanent magnet synchronous motor) which is widely applied in the industry is taken as a research object, the parameters of a controller are optimized to realize accurate position control and further improve the rapidity of system positioning, a new IFT framework is integrated, namely, a closed-loop subspace identification method based on an impulse response model is introduced into a dual-cycle IFT algorithm, the optimal step length is obtained by using a minimum criterion function gradient, and the limitation that the traditional IFT algorithm needs multiple experiments for each iteration and the convergence speed is generally slow is changed; the dual-cycle IFT algorithm can realize online tuning in the operation process, and meets the robustness of the dual-cycle IFT algorithm in different control input environments, so that the optimized PMSM can be further popularized to practical engineering objects such as medical robots, high-precision numerical control equipment and the like.
Detailed Description
The following further describes the embodiments of the present invention with reference to the drawings.
With reference to fig. 1 to 9, in the present application, in order to implement the system specifically, a set of motor experiment platform constructed by an ansha permanent magnet synchronous motor, a power circuit module and a control circuit module is established, and by collecting the real-time position and speed of the motor and transmitting the position and speed to the control circuit module, closed-loop feedback control can be implemented, so that the effectiveness of a control strategy of the permanent magnet synchronous motor can be embodied.
The power circuit module consists of a rectification circuit, an inverter bridge and an isolation driving circuit. The rectification circuit comprises a power-on protection circuit consisting of a rectifier bridge module GBJ3510, a relay and a starting resistor, and the inverter bridge adopts a three-phase full-bridge inverter circuit formed by connecting 6 IGBTs and a freewheeling diode in parallel to convert direct current into equivalent three-phase sinusoidal alternating current. The PC923 is used as an upper bridge arm driving chip, and the PC929 is used as a corresponding lower bridge arm driving chip to jointly form an isolation driving circuit.
The control circuit module is built by taking a DSP (digital signal processor) TMS320F28335 as a core control chip, and specifically comprises a peripheral interface circuit, a current detection circuit, a direct current bus voltage detection circuit and a rotating speed detection circuit, wherein the circuits in the application are conventional circuits in the field, so that the circuit principle of the control circuit is not described in detail in the application. TMS320F28335 is a processing chip with high-speed floating point arithmetic capability, and the abundant peripheral resources are very convenient for servo system control. The current detection circuit consists of a current transformer and an instrument amplifier INA199, so that the current loop control can be realized to acquire the motor current on one hand, and the reason of some faults can be determined according to the acquired three-phase current on the other hand. The direct current bus voltage detection circuit adopts the linear optical accident isolation chip HCNR201 as a core to acquire an accurate direct current bus voltage value. The rotating speed detection circuit measures the rotating speed of the motor by using a 2500-wire incremental photoelectric encoder and sends the rotating speed to the DSP.
Based on a double-loop iterative feedback setting algorithm, a position signal r is set to be 30 degrees, a motor runs in a no-load mode, the influence of white noise v with zero mean value is applied to the motor in the working process, and the sampling time T is 1 multiplied by 10-4s, in order to compare the performance of the conventional IFT algorithm and the dual-cycle IFT algorithm, a set of simulation experiments is first set for verification, and the system simulation parameters of the example are shown in the following table 1:
TABLE 1
First, in the experiment, rho is [ K ]p100]Feedback controller C (z)-1ρ) is:
when the permanent magnet synchronous motor system runs, the first N sampling points in the pulse response experiment are taken, and N is 200. In a stable range with only one local optimum, respectively using the traditional IFT algorithm and the two-cycle IFT algorithm to make KpIterate from 20, with J (ρ) with respect to KpIn particular, K under the two-cycle IFT algorithmpThe curve of the variation of (2) is divided into two sections, including a curve 1 and a curve 2. It can be seen that the conventional IFT algorithm starts from the starting point K p120 linear approximation convergence interval, and K under dual-cycle IFT algorithmpThe optimal step length can be directly obtained, the iteration times are reduced to be within 3 times, and certain deviation exists when the optimal solution is obtained through the dual-cycle IFT algorithm due to errors brought by identification of the speed ring and the limitation of the size of the sampling point N in consideration of calculation complexity. Next, multiple control experiments were set up, each experiment KpThe iteration is started from 25, 30, 35 and 40 respectively, the change trend of the two different algorithms is shown in fig. 5, and it can be seen that the two-cycle IFT algorithm has higher iteration efficiency in one-dimensional space compared with the traditional IFT algorithm. Taking rho ═ KpKI],Kp、 KIRespectively proportional gain and integral gain, and determining rho according to the traditional PID parameter setting method Ziegler-Nichols method0=[42.75 419]Feedback controller C (z)-1ρ) is:
after 20 iterations, KI、KpAnd the change condition of the criterion function J (rho) is shown in fig. 6, the dual-loop algorithm can reach a local optimum within 3 iterations, and compared with a traditional IFT algorithm linear approximation mode, the K under the dual-loop algorithmI、KpAnd the criterion function J (ρ) has a higher iteration efficiency. In another aspect, the dual-loop algorithm has some limitations, except for the error caused by the identification of the speed loopSome local optima may cause the two algorithms to converge to a different optimal point ρ*. As shown in fig. 7, it shows a graph of the position tracking behavior of the permanent magnet synchronous motor under different algorithms and an enlarged view of the oscillation position thereof in this case, specifically, curve 3 is the tracking behavior curve of a given track, curve 4 is the tracking behavior curve of ZN algorithm, curve 5 is the tracking behavior curve of dual sequential IFT algorithm, and curve 6 is the tracking behavior curve of conventional IFT algorithm. Fig. 8 is a graph showing a variation of the rotation speed of the permanent magnet synchronous motor and an enlarged view of the oscillation position thereof, and specifically, a curve 7 is a variation of the rotation speed of the conventional IFT algorithm, a curve 8 is a variation of the rotation speed of the dual sequential IFT algorithm, and a curve 9 is a variation of the rotation speed of the ZN algorithm. Fig. 9 shows the stator current vector id、iqGraph of the variation.
What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiment. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and concept of the present invention are to be considered as included within the scope of the present invention.