CN208158473U

CN208158473U - A kind of brushless DC motor control system

Info

Publication number: CN208158473U
Application number: CN201820548211.2U
Authority: CN
Inventors: 孙灿; 顾聪; 王晓琳
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2018-04-18
Filing date: 2018-04-18
Publication date: 2018-11-27
Anticipated expiration: 2028-04-18

Abstract

The utility model discloses a brushless DC motor control system, which belongs to the technical field of electric power transmission. The utility model uses a front-stage DC-DC converter cascaded with a rear-stage three-phase full-bridge inverter as the power supply topology of the brushless DC motor, and obtains the required voltage of the inverter by controlling the DC-DC converter, and detects phase The current lags behind the phase difference of the opposite electromotive force to compensate the phase of the measured position signal, and obtain the commutation signal of the motor at ultra-high speed, and commutate the brushless DC motor through the switch state of the three-phase full-bridge inverter in the subsequent stage . This system can reduce the adverse effect caused by the phase current lagging behind the opposite electromotive force when the motor is running at ultra-high speed, and realize the position sensorless and MTPA control of the brushless DC motor.

Description

A kind of brushless DC motor control system

Technical field

The utility model provides a kind of brushless DC motor control system, belongs to electric drive technology field.

Background technique

In recent years, permanent-magnet brushless DC electric machine obtains more and more extensive because of the advantages that its power density is high, control is simple Using.Traditional permanent-magnet brushless DC electric machine control system without position sensor, using " counter electromotive force " method, by detecting motor Counter electromotive force obtains rotor-position signal.However, the system tends not to obtain accurate motor commutation point, motor is influenced Can, mainly there is following three points reason：

In " 1. counter electromotive force " method use filter circuit, make the phase voltage zero crossing got usually with practical phase voltage There are phase errors between zero crossing, and the offset of motor commutation point is caused to cause reversing error；

2. since motor is there are winding induction reactance, phase current cannot be mutated when commutation, so that electric current raising and lowering requires Regular hour causes phase current to lag behind phase back-emf.When motor is in high-speed cruising state, phase current is lagged more Seriously.

Utility model content

The utility model aiming at the problems existing in the prior art, proposes a kind of brushless DC motor control system, energy It is enough to obtain accurate reversal point in the operation of motor ultrahigh speed, so as to improve motor performance.

In order to solve the above technical problems, the utility model provides a kind of brushless DC motor control system, including brushless straight Flow motor body, DC-DC converter, three-phase full-bridge inverter, position detection unit, phase difference detector, compensation angle controller With commutation logic unit；The DC-DC converter is opened up with three-phase full-bridge inverter cascade as the power supply of brshless DC motor ontology It flutters, controls DC-DC converter for voltage needed for extraneous input voltage regulation to three-phase full-bridge inverter bus；

Position detection unit, the preliminary commutation by the phase voltage zero crossing of detection three-phase inverter output, as motor Point；

Phase difference detector finds out phase current lag by the phase voltage of detection three-phase inverter output, phase current signal In the phase difference of phase back-emf；

Angle controller is compensated, according to the phase difference, obtains corresponding phase voltage compensation angle, it will be preliminary using coordinate transform Reversal point is transformed into required best commutation signal；

Commutation logic unit obtains best commutation signal, controls the on-off of three-phase full-bridge inverter switching tube, realizes brushless The position-sensor-free and maximum torque per ampere control of direct current generator ontology.

Further, the DC-DC converter can be Buck converter, Buckboost converter, Boost In any one.

Further, counter electromotive force method, magnetic linkage method or triple-frequency harmonics method can be used in the position detection unit.

Further, the phase difference detector calculates rotor flux letter by phase voltage signal and phase current signal Number, replace phase current to lag behind the phase of phase back-emf with the phase difference of phase current signal and rotor flux signal after integral Difference.

Further, the three-phase full-bridge inverter, DC-DC converter switching tube using metal-oxide-semiconductor, triode or Any one in IGBT.

Beneficial effect：Compared with prior art, the utility model has the following advantages that the utility model：

1, system control panel can be made of discrete component, be easily integrated, small volume；

2, system is brshless DC motor in high-speed cruising, and detection rotor-position provides a solution；

3, the phase difference that phase difference detector acquires considers the problem of phase current cannot be mutated in commutation, improves electricity The accuracy at machine reversal point compensation angle；

4, the motor commutation point compensation angle that compensation angle controller obtains is mentioned independent of motor, voltage detecting circuit parameter The high practicability of control system.

Detailed description of the invention

Fig. 1 is the systematic control algorithm block diagram of the utility model.

Specific embodiment

The utility model is described further below in conjunction with attached drawing.

The utility model discloses a kind of brushless DC motor control systems, as shown in Figure 1, including brshless DC motor sheet Body, DC-DC converter, three-phase full-bridge inverter, position detection unit, phase difference detector, compensation angle controller, commutation logic Unit, concrete operation step are as follows：

Step 1), DC-DC converter is by voltage needed for extraneous input voltage regulation to three-phase full-bridge inverter bus；

Step 2), the phase voltage zero crossing that position detection unit is exported by detection three-phase inverter, as the first of motor Walk reversal point；

Step 3), phase difference detector find out mutually electricity by detecting the phase voltage, phase current signal that three-phase inverter exports Stream lags behind the phase difference of phase back-emf；

Step 4), the phase difference that compensation angle controller is found out according to step 3) obtain corresponding phase voltage compensation angle, utilize Preliminary reversal point is transformed into required best commutation signal by coordinate transform；

Step 5), the best commutation signal that commutation logic unit is obtained according to step 4), control inverter switching device pipe lead to It is disconnected, realize position-sensor-free and maximum torque per ampere control of the brshless DC motor under ultrahigh speed.

The DC-DC converter can be Buck converter, Buckboost converter, any one in Boost Kind.

Counter electromotive force method, magnetic linkage method, triple-frequency harmonics method etc. can be used in the position detection unit.

Magnetic linkage method reversal point correcting technology can be used in the phase difference detector, by the phase electricity for detecting brshless DC motor Stream, phase voltage, release rotor flux expression formula are ψ_a=∫ u_adt-L_ei_a.Since rotor flux is the integral of phase back-emf, answer It obtains equally lagging 90 ° of electrical angles so electric current is also done integral transformation with same-phase after counter electromotive force 90 ° of electrical angles of lag Signal i '.Phase current is replaced to lag behind phase back-emf with the phase difference of phase current signal and rotor flux signal after integral Phase difference.

The inverter, DC-DC converter switching tube using metal-oxide-semiconductor, triode, any one in IGBT.

Claims

1. A brushless DC motor control system, characterized in that: comprise a brushless DC motor body, a DC-DC converter, a three-phase full-bridge inverter, a position detection unit, a phase difference detector, a compensation angle controller and Commutation logic unit; the DC-DC converter is cascaded with the three-phase full-bridge inverter as the power supply topology of the brushless DC motor body, and the DC-DC converter is controlled to adjust the external input voltage to the three-phase full-bridge inverter The required voltage of the busbar;

The position detection unit is used as the initial commutation point of the motor by detecting the zero-crossing point of the phase voltage output by the three-phase inverter;

The phase difference detector, by detecting the phase voltage and phase current signals output by the three-phase inverter, obtains the phase difference of the phase current lagging behind the opposite electromotive force;

The compensation angle controller obtains the corresponding phase voltage compensation angle according to the phase difference, and converts the initial commutation point into the required optimal commutation signal by coordinate transformation;

The commutation logic unit obtains the optimal commutation signal, controls the on-off of the switch tube of the three-phase full-bridge inverter, and realizes the position sensorless and maximum torque-current ratio control of the brushless DC motor body.

2. The brushless DC motor control system according to claim 1, wherein the DC-DC converter can be any one of a Buck converter, a Buckboost converter and a Boost converter.

3 . The brushless DC motor control system according to claim 1 , wherein the position detection unit can adopt a back electromotive force method, a flux linkage method or a third harmonic method. 4 .

4. The brushless DC motor control system according to claim 1, wherein the phase difference detector calculates the rotor flux signal through the phase voltage signal and the phase current signal, and uses the integrated phase current signal and the rotor The phase difference of the flux linkage signal replaces the phase difference of the phase current lagging behind the opposite electromotive force.

5. The brushless DC motor control system according to claim 1, characterized in that, the switching tubes of the three-phase full-bridge inverter and the DC-DC converter adopt any one of MOS tubes, triodes or IGBTs .