阅读说明：本技术 永磁同步电机的直轴判断方法 (The d-axis judgment method of permanent magnet synchronous motor ) 是由 徐波 袁健 杨烨 于 2018-05-19 设计创作，主要内容包括：本发明公开了一种永磁同步电机的直轴判断方法,采用脉振高频电流注入法构建转子闭环系统,获取直轴电压响应；记录直轴电压响应在注入电流信号相位为<Image he="71" wi="258" file="DDA0001666321520000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>时的幅值；比较两个幅值大小,判断直轴正方向,得到直轴正方向判断后的补偿值。本发明在判断直轴正方向过程中,注入的电流始终为正弦高频信号,无需注入正负脉冲等其它形式的信号,简化估计过程；对电机运行无影响,结构简单,可靠性高,降低操作的复杂性,简化初始位置估计过程。(The invention discloses a kind of d-axis judgment methods of permanent magnet synchronous motor, construct rotor closed-loop system using pulsating high frequency current injection, obtain direct-axis voltage response；Record direct-axis voltage, which is responded in Injection Current signal phase, is When amplitude；Compare two amplitude sizes, judges d-axis positive direction, the offset after obtaining the judgement of d-axis positive direction.For the present invention during judging d-axis positive direction, the electric current of injection is always sinusoidal high-frequency signal, without injecting the signal of the other forms such as positive negative pulse stuffing, simplifies estimation procedure；On motor operation without influence, structure is simple, high reliablity, reduces the complexity of operation, simplifies initial position estimation process.)

1. a kind of d-axis judgment method of permanent magnet synchronous motor, it is characterised in that the following steps are included:

Step 1: constructing rotor closed-loop system using pulsating high frequency current injection, direct-axis voltage response (1) is obtained；

Step 2: amplitude of the record direct-axis voltage response (1) when Injection Current signal phase is pi/2,3 pi/2；

Step 3: comparing two amplitude sizes, d-axis positive direction is judged, the offset after obtaining the judgement of d-axis positive direction.

2. d-axis judgment method as described in claim 1, it is characterised in that: in the step 1, estimate rotor synchronous rotary Coordinate system quadrature axis current is given as 0, injects a pulsating high frequency sinusoidal signal to direct-axis current, constructs rotor closed-loop system, mention The direct-axis voltage of rotor synchronous rotating frame is taken to respond

3. d-axis judgment method according to claim 1, it is characterised in that: in the step 2, record direct-axis voltage is rung It answersIn ω_h=pi/2 and ω_hVoltage magnitude when=3 pi/2

4. d-axis judgment method according to claim 1 or 3, it is characterised in that: in the step 3, d-axis is responded electricity PressureAfter being sent into low-pass filtering (2), the response voltage of removal high-frequency signal interference is obtained | U₁|、|U₂|, then compare sound Voltage magnitude size is answered, judges d-axis positive direction, the offset after obtaining the judgement of d-axis positive direction.

5. d-axis judgment method according to claim 4, it is characterised in that: if | U₁| < | U₂|, then d-axis positive direction and magnetic Pole N is extremely in the same direction, and the offset after d-axis positive direction judges is 0；If | U₁| > | U₂|, then d-axis positive direction and magnetic pole N are extremely reversed, D-axis positive direction judge after offset as π.

Technical field

The present invention relates to motor field, the d-axis positive direction judgment method of especially a kind of permanent magnet synchronous motor.

Background technique

Under normal circumstances, due to the uniqueness of durface mounted permanent magnet synchronous motor rotor structure design, lead to its rotor not There are saliency in structure, this brings limitation to the application of rotation High Frequency Injection.But it ought artificially utilize inversion electricity Road is in two-phase synchronous rotating frame, and after injecting high frequency sinusoidal signal in the fundamental wave of motor, durface mounted permanent magnet is synchronous at this time The d-axis magnetic circuit of motor changes, so that the cross, straight axle inductance of motor is no longer equal, this phenomenon is referred to as stator inductance Non-linear saturated characteristic.Simultaneously because rotor be it is static, can not be by detection winding back emf come at the beginning of estimating rotor Beginning position.

Liu Ying, cycle, Li Shuai wait rotor magnetic steel durface mounted permanent magnet synchronous electric motor rotor initial position detection [J] Chinese Electrical engineering journal, 2011,31 (18): 48-54. injects high frequency sinusoidal voltage in the d-axis of estimation rotor synchronous rotating frame Signal, detection quadrature axis high-frequency current, which responds and establishes location estimation closed loop, obtains the first estimated value of rotor-position.Estimating again D-axis direction inject generating positive and negative voltage pulse, judge d-axis just using the difference that reversal acts on lower d-axis equivalent time constant Direction, such methods are needed to inject two kinds of signal in initial position estimation overall process, be realized more complicated.Magnetic pole is square To deterministic process need to inject generating positive and negative voltage pulse compare again current-responsive decay to 0 used in the time, this is also required to cost one The fixed time.Liu Ying, cycle, Zhao Chengliang wait to be based on pulsating high-frequency current and inject SPMSM low speed position Sensorless Control [J] China electrotechnics journal, 2012,7 (27): 139-145. uses pulsating high frequency current injection to realize that SPMSM turns for the first time Sub- location estimation, but do not refer to and how d-axis positive direction being judged.

The case where being consulted according to existing literature, there is presently no articles specifically for straight in pulsating high frequency current injection The judgement expansion research of axis positive direction.

Summary of the invention

The present invention is directed to the feature of permanent magnetic synchronous motor structure complexity, under the method for high-frequency current injection, proposes one The d-axis judgment method of kind permanent magnet synchronous motor simplifies estimation procedure without injecting the signal of the other forms such as positive negative pulse stuffing；It is right For motor operation without influence, structure is simple, high reliablity, reduces the complexity of operation, simplifies initial position estimation process.

The technical solution for realizing the aim of the invention is as follows: a kind of d-axis judgment method of permanent magnet synchronous motor, including such as Lower step:

Step 1: constructing rotor closed-loop system using pulsating high frequency current injection, direct-axis voltage response is obtained；

Step 2: amplitude of the record direct-axis voltage response when Injection Current signal phase is pi/2,3 pi/2；

Step 3: comparing two amplitude sizes, d-axis positive direction is judged, the offset after obtaining the judgement of d-axis positive direction.

Compared with prior art, the present invention its remarkable advantage are as follows:

(1) for the present invention during judging d-axis positive direction, the electric current of injection is always sinusoidal high-frequency signal, without injection The signal of the other forms such as positive negative pulse stuffing, simplifies estimation procedure；

(2) due to not having to injection positive negative pulse stuffing voltage, reduce the time of initial position of rotor estimation, while because not needing The peak value of response current signal is detected, so not being very high, reduction hardware cost to the required precision of sample circuit.

(3) voltage magnitude of the present invention record d shaft voltage response when Injection Current signal phase is pi/2 and 3 pi/2, leads to It crosses and compares amplitude size and judge that d axis positive direction, the process can be completed within the period of an Injection Current signal, shorten d The time required to axis positive direction deterministic process.

(4) d axis judgment method of the present invention is very suitable to high frequency current injection, and on motor operation without influence, structure is simple, High reliablity reduces the complexity of operation, simplifies initial position estimation process.

Detailed description of the invention

Fig. 1 is the signal extraction of d-axis positive direction judgement and the functional block diagram of modulated process.

Fig. 2 is rotor closed-loop control block diagram of the durface mounted permanent magnet synchronous electric motor rotor based on high frequency current injection.

Fig. 3 is two-phase stationary coordinate system, practical two-phase synchronous rotating frame and estimation two-phase synchronous rotating frame Relativeness schematic diagram.

In figure: 1 is recording voltage amplitude, and 2 be low-pass filter, and 3 be proportional and integral controller (PI), and 4 be Park inversion It changes, 5 be space vector pulse width modulation, and 6 be 3 phase inverters, and 7 synchronize electric (SPMSM) for durface mounted permanent magnet, and 8 convert for Clarke, 9 convert for Park.

Specific embodiment

The invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention provides a kind of d-axis judgment method of permanent magnet synchronous motor, specifically includes the following steps:

Step 1: constructing rotor closed-loop system using pulsating high frequency current injection, direct-axis voltage response is obtained；

Step 2: amplitude of the record direct-axis voltage response when Injection Current signal phase is pi/2,3 pi/2；

Step 3: comparing two amplitude sizes, d-axis positive direction is judged, the complement value after obtaining the judgement of d-axis positive direction.

Further, in step 1, the stator magnetic linkage of permanent magnet synchronous motor is common by threephase stator electric current and rotor permanent magnet Effect generates, related with rotor-position, and flux linkage equations indicate are as follows:

In formula, ψ_A、ψ_B、ψ_CFor the magnetic linkage of threephase armature winding；For durface mounted permanent magnet synchronous motor, because of air gap Uniformly, the self-induction of three-phase windings and mutual inductance are all unrelated with rotor-position, are constant value, and the self-induction of every phase winding is L_AA=L_BB= L_CC；Mutual inductance M between two phase windings_AB=M_BA=M_BC=M_CB=M_AC=M_CA.Stator voltage equation is obtained as a result, are as follows:

In formula, u_A、u_B、u_CIt is the phase voltage of threephase stator armature winding, i_A、i_B、i_CIt is the phase of threephase stator armature winding Electric current, R_A=R_B=R_C=R_SFor the resistance of threephase stator armature winding, p is differential operator.

Can be seen that the mathematical model that permanent magnet synchronous motor is established under three-phase static coordinate system from both the above equation is One non-linear and coupling multi-variable system, is unfavorable for analysis and control.

For simplifying the analysis, stator current space vector i is defined_sAre as follows:

In formula, operator a=e^j2π/3、a²=e^j4π/3。

The real axis of stator current space vector is a axis, is overlapped with the A phase axis as of stator winding；The imaginary axis is β axis, advanced α 90 ° of electrical angles of axis.This realizes transformation of the three-phase static coordinate system to two-phase stationary coordinate system, referred to as Clarke transformation, electric current Relationship and transformation matrix are as follows:

In formula, i_α、i_βRespectively α, β shaft current.

Orientation on rotor flux is used in amount control, magnetic field of permanent magnet N pole direction is set as d-axis (d axis), presses The axis for rotating in the forward direction advanced 10 electrical angle of d axis in direction according to motor is quadrature axis, two-phase rotating coordinate system is constituted, by the static seat of two-phase Mark system transforms to two-phase rotating coordinate system, referred to as Park variation, current relationship and transformation matrix are as follows:

In formula, i_d、i_qRespectively d, q shaft current.

Above-mentioned transformation relation is equally applicable to voltage and magnetic linkage, constant to meet transformation front and back power, under two phase coordinate systems The number of turns of every phase winding is every phase winding effective turn under former three phase coordinate systemsTimes.Utilize above two coordinate transform square Battle array, can establish the mathematical model under permanent magnet synchronous motor two-phase rotating coordinate system.

(1) flux linkage equations

In formula, ψ_d、ψ_qAnd L_d、L_qThe respectively magnetic linkage and inductance of d, q axis.

(2) voltage equation

In formula, U_d、U_qRespectively d, q shaft voltage, and think p ψ_f=0.Under steady state conditions, voltage equation can be write Out:

(3) torque equation

T_e=pn (ψ_di_q-ψ_qi_d)=pn [ψ_fi_q+(L_d-L_q)i_di_q] (9)

In formula, p_nIt is the number of pole-pairs of permanent magnet synchronous motor.Torque consists of two parts, and first part is main electromagnetic torque, It is directly proportional to q shaft current as produced by stator rotating excitation field and permanent magnetic field interaction；Second part is reluctance torque, is It is generated due to cross, straight axle inductance difference, and directly proportional to salient pole ratio.

Research object is durface mounted permanent magnet synchronous motor, it is generally the case that cross, straight axle inductance is of substantially equal, then its turn Moment equation can be reduced to

T_e=pn ψ_fi_q (10)

Only include the electromagnetic torque directly proportional to q shaft current it can be seen that there is no reluctance torque in torque equation, is highly convenient for turning Square control.

From formula (10) as can be seen that using after vector controlled, permasyn morot turns under two-phase rotating coordinate system Square is codetermined by q shaft current and magnetic field, and magnetic field of permanent magnet remains unchanged, and can be attributed to the control of motor torque to fixed Cross, straight shaft current is respectively controlled in electron current.The essence of vector controlled is exactly by coordinate transform theory, stator current Resolution of vectors is at torque current component i_qWith excitation current component i_dTwo, realize the decoupling control of torque and magnetic flux.

It, can be current control in permanent magnet synchronous motor vector controlled according to the difference to cross, straight shaft current control mode Strategy is divided into: d shaft current is zero control, torque current than maximum control, unity power factor control and constant magnetic linkage control.Its Middle unity power factor control and constant magnetic linkage control are relatively more suitable for high power permanent magnet synchronous motor control system, they have The advantages that power factor height and reduction inverter capacity.D shaft current is zero control, i.e. i_d=0 control, it be in vector controlled most Simple Current Control Strategy.The advantages of control strategy is to control that most simple, calculation amount is small, will not generate demagnetizing effect and cause Permanent magnet demagnetizes and motor performance is made to degenerate, therefore is widely applied.The shortcomings that control strategy, is: 1) after load increases Power factor decreases；2) reluctance torque cannot be exported.Torque current refers to torque conditions same in output phase than maximum control Under, motor stator electric current is minimum, can reduce copper loss and inverter losses.The durface mounted permanent magnet synchronous motor category that the present invention studies In middle low power range, motor does not have the ability of output reluctance torque inherently, uses i_d=0 control strategy, with torque Electric current is consistent than maximum current control, and reason is that stator current is all used to generate torque at this time.

Coordinate system relational graph is established, as shown in figure 3, dq is actual synchronization rotating coordinate system,For the synchronous rotation of estimation rotor Turn coordinate system, α β is practical two-phase stationary coordinate system, and defines evaluated errorWherein, θ is that actual rotor is initial Position,For final initial position estimation value,Initial value be 0.As shown in Fig. 2, will estimate rotor synchronous rotating frame q Shaft current is given as 0, d shaft current and is given as a pulsating high frequency sinusoidal signal I_mh sin(ω_hT), wherein I_mhTo be infused in d axis Enter the amplitude of high-frequency current, ω_hFor the angular frequency for injecting high-frequency current in d axis, t indicates current time.Using proportional integration tune Section device (PI) controls the d shaft current and q shaft current of estimation, makes it and gives unanimously；Comparative example integral controller (PI) The voltage of outputWithPark inverse transformation is carried out, the voltage u under the static α β coordinate system of two-phase is obtained_αAnd u_β, then using space arrow Amount pulsewidth modulation strategy obtains six path switching signals of three-phase inverter, drives durface mounted permanent magnet synchronous motor PMSM；Detection electricity A phase and B phase current in machine three-phase windings A/B/C, as shown in Fig. 2, the static α β coordinate of two-phase is arrived in advance Clarke transformation Electric current i under system_αAnd i_β, convert to obtain the d shaft current under estimation rotor synchronous rotating frame using ParkWith q axis electricity StreamIt is fed back to the input terminal of pi regulator；Extract the d shaft voltage response of rotor synchronous rotating frame

Further, in step 2, as shown in Figure 1, for durface mounted permanent magnet synchronous motor, when d shaft current plays increasing magnetic action Magnetic field saturation, inductance reduce；Saturation is moved back in magnetic field when d shaft current plays demagnetizing effect, and inductance increases.Liu Ying, cycle, Zhao Chengliang wait SPMSM low speed position Sensorless Control [J] China electrotechnics journal is injected based on pulsating high-frequency current, 2012,7 (27): After 139-145. gives injection pulsating high-frequency current, permanent magnet synchronous motor is rung in the synchronous rotating frame d shaft voltage of estimation It answers are as follows:

After completing first initial position estimation, position estimation error Δ θ is 0 or π, substitutes into formula (11) and such as obtains:

In formula,For average impedance,For half poor impedance.Substitution formula (12):

In formula, Z_d=r_s+jω_hL_dFor d axis high-frequency resistance, r_sFor stator resistance, L_dFor d axle inductance.Due to the resistance of winding Much smaller than the high-frequency resistance of winding, therefore the resistance drop of negligible stator winding, it is obtained by formula (13):

Work as ω_hWhen t=pi/2, substitutes into formula (14) and obtainIt records at this timeShaft voltage amplitude | U₁|；When ω_hWhen t=3 pi/2,It records at this timeShaft voltage amplitude | U₂|。

Further, in step 3, as Δ θ=0, ω_hWhen t=pi/2, magnetic potential and d axis positive direction one that stator current generates It causing, magnetic circuit saturation, stator d axle inductance becomes smaller, | U₁| it is smaller；ω_hThe magnetic potential and d axis positive direction phase that t=3 pi/2 stator current generates Instead, magnetic circuit moves back saturation, and stator d axle inductance becomes larger, | U₂| it is larger, therefore | U₁| < | U₂|。

As Δ θ=π, ω_hWhen t=pi/2, the magnetic potential and d axis positive direction that stator current generates are on the contrary, magnetic circuit moves back saturation, calmly Sub- d axle inductance becomes larger, | U₁| it is larger；ω_hT=3 pi/2, | U₂| it is smaller, therefore | U₁| > | U₂|。

In order to avoid interfering and judging by accident, the value of d-axis response voltage will could be used for comparison operation after filtering.If | U₁ | < | U₂|, then d axis positive direction and magnetic pole N are extremely in the same direction, and the offset after d axis positive direction judges is 0；If | U₁| > | U₂|, then d axis Positive direction and magnetic pole N are extremely reversed, d axis positive direction judge after offset as π.