CN102035445A - High-speed weak magnetic closed loop control method for permanent magnetic synchronous motor - Google Patents

Abstract

The invention is applied to the field of high-speed weak magnetic control of a permanent magnetic synchronous motor, and in particular provides a new closed loop weak magnetic control method aiming at the high-speed weak magnetic control of the permanent magnetism synchronous motor. In the invention, the weak magnetic closed loop control ideas is adopted as follows: the neutral phase voltage Vr can be calculated by using the D shaft voltage Vdr and the Q shaft voltage Vqr of the permanent magnetic synchronous motor by a vector control method, and after the Vr is obtained, the Vr is compared with reference voltage Vbase, and finally negative Idr is obtained by a negative feedback PI regulator; as the rotating speed of the permanent magnetic synchronous machine rises, the Vdr and the Vqr increase and the Vr also increases; when the Vr exceeds the Vbase, the negative Idr is output, and the negative Idr just offsets part of the permanent magnetic field, thereby ensuring the increase of speed; and as the absolute value of Idr increases, the limited field [iqrmin, iqrmax] of the Iqr decreases to ensure that the total current does not exceed Ismax. The weak magnetic closed loop control method adopted by the invention achieves the purpose of demagnetization.

Description

The at a high speed weak magnetic closed loop control method of a kind of permagnetic synchronous motor

Technical field

The present invention relates to the at a high speed weak magnetic closed loop control method of a kind of permagnetic synchronous motor, be mainly used in the weak magnetic control system field of high speed of permagnetic synchronous motor.

Background technology

Along with the minimizing day by day of petroleum-based energy and the growing interest of human environmental pollution, electric automobile and the hybrid power automobile power system that constitutes with permanent-magnet synchronous and AC induction motor caused showing great attention to of each automobile vendor now.The weak magnetic of the high speed of current permagnetic synchronous motor generally adopts open loop control.Weak magnetic open loop control needs the at a high speed weak magnetic dot parameter of test, and workload is very big, calculates loaded down with trivial details; Change different motors and need test again; Supply power voltage changes, and test parameter originally needs to revise.The present invention is directed to the shortcoming of above method, design a kind of new control method, finally realize the weak magnetic control system of real-time closed loop.

The content of invention

The present invention provides a kind of new high speed field weakening control method in order to overcome deficiency of the prior art.The increase of stator current frequency can realize high speed processing.The angular speed of stator voltage and flow motor is directly proportional.Under normal operation, flow motor remains unchanged.When maximum speed reaches stator, be subjected to the restriction of power supply changeover device output voltage.In order to reach higher speed, flux reduces to the state that stator voltage keeps constant and maximum equality as angular speed.After permagnetic synchronous motor ran to normal speed, the back electromotive force that motor produces equaled cell voltage, at this moment will continue raising speed and must reduce excitation.At the fixed magnetic field of permagnetic synchronous motor, reduce excitation, by add a negative electric current in the d-axis direction, produce a magnetic field opposite, thereby offset a part of magnetic field with fixed magnetic field, reach the purpose of weak magnetic.

The present invention solves the technical scheme that its technical problem takes: utilize D shaft voltage Vdr and Q shaft voltage Vqr can calculate neutral phase voltage Vr, after obtaining Vr, compare with reference voltage Vbase, the final Idr that obtains bearing by the negative feedback pi regulator, and the magnetic field that negative Idr produces is opposite with the fixed magnetic field direction, balance out a part of fixed magnetic field, and rising along with rotating speed, the negative Idr that pi regulator obtains is big more, thereby the magnetic field of offsetting is many more, obtain more weak magnetic field, finally realize the weak magnetic control system of real-time closed loop.And along with the increase of the absolute value of Idr, the limited field of Iqr [iqrmin, iqrmax] will reduce, and guarantee that total current does not exceed Ismax.

The present invention compared with prior art, the performance of its beneficial effect is as follows:

1. need not to test in advance at a high speed weak magnetic dot, adopt the real-time operation of closed-loop control strategy to realize.

2. need only import parameter of electric machine ψ f when changing motor gets final product.

3. when supply power voltage takes place, adjust weak magnetic dot synchronously, reduced and revised the improper error of bringing by closed-loop control.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is a flow chart of the present invention.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described further:

The weak magnetic close loop negative feedback PI control strategy that the present invention proposes, all parameters all are real-time calculating, must not table look-up and also not utilize approximate static parameter, have solved the shortcoming of open cycle system completely.Realize principle as shown in Figure 1.

The specific implementation process:

The first step: utilize the D axle and the Q shaft voltage of permagnetic synchronous motor, obtain new D axle as shown in drawings, can determine neutral phase voltage Vr by Vdr and Vqr with reference to input Idr. by pi regulator, as (1) formula:

$\mathrm{Vr}=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="Vdr"\; filenames="H2009100706254E0000011.png,H2009100706254E0000021.png"\; state="\{\{state\}\}">Vdr</figure-callout>}}^2+{\mathrm{Vqr}}^2}---\left(1\right)$

Second step: Vr and reference voltage Vbase have been arranged, obtained Idr. by the negative feedback pi regulator

The 3rd the step: do not exceed Ismax in order to ensure total current, the limited field of Iqr [iqrmin, iqrmax] will by

(2) formula calculates

$\mathrm{iq}\max =\sqrt{{\mathrm{is}\max }^2-{\mathrm{idr}}^2}---\left(2\right)$

Realize extracting operation by recursion equation in the software.Specific algorithm is as (3) formula:

X(n)＝0.5*(X(n-1)+N/X(n-1)) (3)

Utilize technical solutions according to the invention, or those skilled in the art designing the similar techniques scheme under the inspiration of technical solution of the present invention, and reach above-mentioned technique effect, all is to fall into protection scope of the present invention.

Claims (4)

1. the at a high speed weak magnetic closed loop control method of a permagnetic synchronous motor, it is characterized in that: used control method adopts closed-loop control to combine with vector control method.

2. the at a high speed weak magnetic closed loop control method of a kind of permagnetic synchronous motor according to claim 1 is characterized in that: utilize the D axle and the Q shaft voltage of permagnetic synchronous motor, can determine neutral phase voltage Vr by Vdr and Vqr.

3. the at a high speed weak magnetic closed loop control method of a kind of permagnetic synchronous motor according to claim 1 is characterized in that: according to Vr and reference voltage Vbase, obtain Idr. by the negative feedback pi regulator

4. the at a high speed weak magnetic closed loop control method of a kind of permagnetic synchronous motor according to claim 1 is characterized in that: do not exceed Ismax in order to ensure total current, can calculate the limited field [iqrmin, iqrmax] of Iqr.

Images