CN105262397B - A kind of variable-frequency motor location current control method - Google Patents

Abstract

The present invention relates to air conditioner controlling technology, it discloses a kind of variable-frequency motor location current control method, solving the problem of in traditional permanent-magnet synchronous DC brushless motor location technology that upper and lower six IGBT power-up sequences will not change causes IGBT service lifes different in size.Variable-frequency motor location current control method in the present invention, including：D shaft currents are controlled from 0 to positioning target current I_d0Variation, control q shaft currents are 0, and when starting positioning for the first time, control orientation angle θ is 0 degree；Hereafter during each positioning starting, the relatively last positioning variation fixed angle n of control orientation angle θ.The present invention can make the average time that every IGBT is connected during positioning equal, IGBT service lifes are not influenced by positioning, extend the service life of IGBT, solve the problems, such as that the conventional mapping methods IGBT service life is inconsistent, product use time is improved, is controlled suitable for air-conditioning variable-frequency motor location current.

Description

A kind of variable-frequency motor location current control method

Technical field

The present invention relates to air conditioner controlling technologies, more particularly to variable-frequency motor location current control method.

Background technology

Traditional permanent-magnet synchronous DC brushless motor localization method, is controlled using location current, and location current generally uses d Shaft current is not equal to 0, and q shaft currents are controlled, but the space vector direction that location current is formed is fixed for 0, are only changed The size of location current, the angle theta between space vector and fixed coordinates axis α axis is constant, and rotor is forced to turn to current phasor Direction, position in this way, can cause to start every time, upper and lower six IGBT power-up sequences will not change, some IGBT (insulated gate bipolar transistor) conduction time is long, and some conduction time is short or even the basic no powers of IGBT that have, transports for a long time Row can cause the IGBT service life inconsistent to happen.

As shown in Figure 1, current phasorIt decomposes under fixed coordinate system u/v/w coordinates, it is assumed thatSize is I_{d_0}, Then I_{u_0}=I_{d_0}Cos θ, I_{v_0}=I_{d_0}Cos (θ -120), I_{w_0}=I_{d_0}Cos (θ+120), when θ is constant, I_{u_0}/I_{v_0}/I_{w_0}Size and I_{d_0}Related, current direction will not change, particularly, as θ=0,As it can be seen that during each positioning starting, electric current fixation flows into motor from U phases Coil, and flowed out from motor V phases and W coils, 6 IGBT, only IGBT a, IGBT e and IGBT f conductings are caused, other are several IGBT is not turned on, as shown in Fig. 2, this localization method is used for a long time, IGBT service lifes will necessarily be caused different in size The problem of occur.

Invention content

The technical problems to be solved by the invention are：It proposes a kind of variable-frequency motor location current control method, solves tradition In permanent-magnet synchronous DC brushless motor location technology, upper and lower six IGBT power-up sequences, which will not change, causes IGBT service lifes long Short the problem of differing.

The present invention solves above-mentioned technical problem the technical scheme adopted is that a kind of variable-frequency motor location current controlling party Method, including：D shaft currents are controlled from 0 to positioning target current I_d0Variation, control q shaft currents are 0, when starting positioning for the first time, control Orientation angle θ processed is 0 degree；Hereafter during each positioning starting, the relatively last positioning variation fixed angles of control orientation angle θ n°。

Further, the mode of relatively last n ° of the positioning variations of the control orientation angle θ is：Control orientation angle θ Relatively last orientation angle increases.

Further, the orientation angle refer to space vector direction and fixed coordinates axis α axis that d shaft currents are formed it Between angle.

Further, described n °=60 °.

The beneficial effects of the invention are as follows：The average time of every IGBT conducting is equal when can make positioning, and IGBT uses the longevity Life is not influenced by positioning, and extends the service life of IGBT, solves the problems, such as that the conventional mapping methods IGBT service life is inconsistent, Improve product use time.

Description of the drawings：

Fig. 1 is current phasor in traditional technologyDecompose fixed coordinate system u/v/w coordinate schematic diagrames；

Fig. 2 is 6 IGBT connection diagrams in traditional technology；

Fig. 3 is variable-frequency motor location current control method flow chart of the present invention.

Specific embodiment

The present invention is directed to propose a kind of variable-frequency motor location current control method, solves the brushless electricity of traditional permanent magnet synchronous DC In machine location technology, upper and lower six IGBT power-up sequences will not change the problem of causing IGBT service lifes different in size.

As shown in figure 3, the solution of the present invention includes：D shaft currents are controlled from 0 to positioning target current I_d0Variation controls q axis Electric current is 0, and when starting positioning for the first time, control orientation angle θ is 0 degree；Hereafter during each positioning starting, orientation angle θ phases are controlled Variation fixed angle n is positioned to the last time.

In specific implementation, starting positioning for the first time, orientation angle is 0 degree, is started every time later, and orientation angle adds 60 degree, Orientation angle θ includes 0 °, 60 °, 120 °, 180 °, 240 °, 300 °, in this way, when θ=0 °, IGBT a, IGBT e and IGBT f Conducting, when θ=60 °, IGBT a, IGBT b and IGBT f conductings, when θ=120 °, IGBT b, IGBT d and IGBT f are led Logical, when θ=180 °, IGBT b, IGBT c and IGBT d conductings, when θ=240 °, IGBT c, IGBT d and IGBT e are led It is logical, when θ=300 °, IGBT a, IGBT c and IGBT e conductings.

It can be seen that the method for this control location current, the average time that can make every IGBT conducting is equal, and IGBT is used Service life is not influenced by positioning, and extends the service life of IGBT, is solved the conventional mapping methods IGBT service life and inconsistent is asked Topic, improves product use time.

Claims (2)

1. a kind of variable-frequency motor location current control method, which is characterized in that including：Control d shaft currents electric from 0 to positioning target Flow I_d0Variation, control q shaft currents are 0, and when starting positioning for the first time, control orientation angle θ is 0 degree；Hereafter during each positioning starting, The relatively last positioning of orientation angle θ is controlled to increase by 60 °.

2. a kind of variable-frequency motor location current control method as described in claim 1, which is characterized in that the orientation angle is Refer to the angle between the space vector direction that is formed of d shaft currents and fixed coordinates axis α axis.