CN104660140A - Permanent magnet synchronous motor initial position detection method based on high-frequency current signal injection - Google Patents

Abstract

The invention discloses a permanent magnet synchronous motor initial position detection method based on high-frequency current signal injection. The method comprises the following step: on the basis of realizing estimation of an initial position by utilizing a fluctuating high frequency current injection method, carrying out d-axis positive direction judgment by extracting d-axis positive direction information included in double injection signal frequency sub-harmonics in d-axis voltage response. According to the method, only high frequency current signals need to be injected in the whole initial position estimation process, and extra signal injection in other forms such as square-wave pulse during the d-axis positive direction judgment process is not needed, so that the estimation time is shortened, and the estimation process is simplified.

Description

Based on the permagnetic synchronous motor initial position detection method that high-frequency current signal injects

Technical field

The present invention relates to Motor Control Field, particularly relate to a kind of permagnetic synchronous motor initial position detection method injected based on high-frequency current signal.

Background technology

For the method for surface-mount type permanent-magnetic synchronous motor rotor initial position detection, because rotor is static, cannot carry out estimated rotor initial position by detecting winding back emf, is all at present generally the mode adopting signal injection, and wherein studying more is High Frequency Injection.

Liu Ying, cycle, Li Shuai, Deng. rotor magnetic steel surface-mount type permanent-magnetic synchronous motor rotor initial position detection [J]. Proceedings of the CSEE, 2011,31 (18): 48-54. inject high frequency sinusoidal voltage signal at the d axle of estimated rotor synchronous rotating frame, detect q axle high-frequency current and respond and set up the first estimated value that location estimation closed loop obtains rotor-position.Inject generating positive and negative voltage pulse at the d direction of principal axis estimated again, utilize the difference of d-axis equivalent time constant under reversal effect to judge d axle positive direction, these class methods need the signal of injection two type in initial position estimation overall process, realize more complicated.Magnetic pole positive direction deterministic process needs to inject generating positive and negative voltage pulse and compares current response again and decayed to for 0 time used, and this also needs to spend the regular hour.Liu Ying, cycle, Zhao Chengliang, Deng. inject SPMSM low speed position Sensorless Control [J] based on pulsating high-frequency current. Chinese electrotechnics journal, 2012,7 (27): 139-145. adopt pulsating high frequency current injection to realize SPMSM rotor position estimate first, but do not mention how judging d axle positive direction.Wang Jianmin, Zhao Xiaomin, Guo Zhen.Analysis andImprovement of Pulsating Current Injection Based Sensorless Control of Permanent MagnetSynchronous Motor [C] .17th International Conference on Electrical Machines and Systems (ICEMS), 2014. also adopt pulsating high frequency current injection to realize the detection of initial position of rotor, and give the scheme that some reduce evaluated error, but do not mention yet and how to judge d axle positive direction.

According to the situation of existing Literature Consult, article is not also had to judge to launch research for the d axle positive direction in pulsating high frequency current injection specially at present.

Summary of the invention

Technical problem to be solved by this invention is the defect for background technology, on the basis of existing initial position detection method, propose a kind of overall process and only need inject high-frequency current signal, do not need the d axle positive direction determination methods of the signal injection of other forms such as square wave, the method makes initial position detection process obviously be simplified.

The present invention is for solving the problems of the technologies described above by the following technical solutions:

Based on the permagnetic synchronous motor initial position detection method that high-frequency current signal injects, comprise following steps:

Step 1), build rotor-position closed-loop regulating system based on pulsating high frequency current injection, obtain the first estimated value of rotor-position;

Step 2), extract the second harmonic component of d shaft voltage response, corresponding signal madulation is carried out to it, judges d axle positive direction, obtain the offset after the judgement of d axle positive direction;

Step 3), first for rotor-position estimated value is added the offset after the judgement of d axle positive direction, obtain final initial position estimation value.

As first process of a kind of permagnetic synchronous motor initial position detection method based on high-frequency current signal injection of the present invention, the step obtaining the first estimated value of rotor-position is as follows:

Step 11), the q shaft current of estimated rotor synchronous rotating frame is given as 0, d shaft current and is given as a pulsating high frequency sinusoidal signal I _mhsin (ω _ht), wherein, I _mhfor injecting the amplitude of high-frequency current at d axle, ω _hfor injecting the angular frequency of high-frequency current at d axle, t represents current time;

Step 12), adoption rate resonant controller PR controls the d shaft current estimated and q shaft current, makes it consistent with given;

Step 13), the voltage that comparative example resonant controller exports with carry out Park inverse transformation, obtain the voltage u under the static alpha-beta coordinate system of two-phase _αand u _β, then adopt space vector pulse width modulation strategy to obtain six path switching signals of three-phase inverter, the mounted permagnetic synchronous motor of table-drive;

Step 14), detect any biphase current in motor three-phase windings A/B/C, first carry out Clarke conversion obtain the static alpha-beta coordinate system of two-phase under current i _αand i _β, then the d shaft current under Park conversion obtains estimated rotor synchronous rotating frame with q shaft current fed back to the input of ratio resonant controller;

Step 15), the q shaft voltage of estimated rotor synchronous rotating frame is responded selecting frequency through band pass filter is ω _halternating current component, be q shaft voltage response first harmonic component again with cosine signal cos (ω _ht) be multiplied and modulate, obtain DC component and frequency is 2 ω _halternating current component, eventually pass low pass filter filtering alternating current component, extract DC component, obtain estimated position deviation signal f _c(Δ θ);

Step 16), build position deviation closed loop, by estimated position deviation signal f _c(Δ θ) as the input of proportional and integral controller, estimated rotor angular speed for the output of proportional and integral controller, to estimated rotor angular speed integration obtains the rotor-position estimated;

Step 17), repeat steps A .1) to steps A .6), until the rotor-position estimated converges to a steady state value, be the first estimated value of initial position of rotor

As a kind of second process of permagnetic synchronous motor initial position detection method injected based on high-frequency current signal of the present invention, described judgement d axle positive direction and obtain d axle positive direction judge after the detailed step of offset as follows:

Step 21), detect the d shaft voltage response of estimated rotor synchronous rotating frame it is first selected the second harmonic component of d shaft voltage response through band pass filter

Step 22), by second harmonic component with sinusoidal signal sin (2 ω _ht) be multiplied and modulate, obtain DC component and frequency is 4 ω _halternating current component, wherein ω _hfor injecting the angular frequency of high-frequency current signal at d axle, t represents current time;

Step 23), by the signal after modulation through low pass filter filtering alternating current component, extract DC component, this DC component is d axle positive direction and judges information g _nS.

Further, according to g _nSsymbol decision d axle positive direction, if g _nSbe less than 0, then the N pole of d axle positive direction and magnetic pole in the same way, and the offset after d axle positive direction judges is 0; If g _nSbe greater than 0, then the N of d axle positive direction and magnetic pole is extremely reverse, and the offset after d axle positive direction judges is π.

The present invention realizes on the basis of first initial position estimation at the traditional pulsating high frequency current injection of employing, extract and estimate that the information in the response of d axle high frequency voltage in two times of Injection Signal frequency subharmonic judges d axle positive direction, the method only need inject high-frequency current signal in initial position estimation overall process, at the signal injection of d axle positive direction deterministic process without the need to other forms such as square waves, reduce the complexity of operation, shorten estimated time, simplify initial position estimation process.

The present invention adopts above technical scheme compared with prior art, has following technique effect:

(1) the present invention is judging that in d axle positive direction process, the electric current of injection is always sinusoidal high-frequency signal, without the need to injecting the signal of other forms such as positive negative pulse stuffing, simplifies estimation procedure;

(2) band pass filter is adopted to obtain estimating the second harmonic component of d axle high frequency voltage response, from second harmonic, the component comprising d axle positive direction information is extracted again by certain modulation, according to the symbol decision d axle positive direction of this component, this process can complete within the cycle of an Injection Current signal, shortens d axle positive direction deterministic process required time.

Accompanying drawing explanation

Fig. 1 is the theory diagram of surface-mount type permanent-magnetic synchronous motor rotor initial position estimation process;

Fig. 2 is two-phase rest frame, actual two-phase synchronous rotating frame and the relativeness schematic diagram estimating two-phase synchronous rotating frame;

Fig. 3 is the signal extraction of first initial position estimation and the theory diagram of modulated process;

Fig. 4 is the signal extraction of d axle positive direction judgement and the theory diagram of modulated process;

When the corresponding actual rotor position of Fig. 5 (a) is 1rad, the simulation waveform of initial position of rotor estimation procedure;

When the corresponding actual rotor position of Fig. 5 (b) is 1rad, d axle positive direction judges information g _nSsimulation waveform;

When the corresponding actual rotor position of Fig. 5 (c) is 3rad, the simulation waveform of initial position of rotor estimation procedure;

When the corresponding actual rotor position of Fig. 5 (d) is 3rad, d axle positive direction judges information g _nSsimulation waveform.

When the corresponding actual rotor position of Fig. 6 (a) is 0.5rad, initial position of rotor estimation procedure and d axle positive direction judge information g _nSexperimental waveform;

When the corresponding actual rotor position of Fig. 6 (b) is 4rad, initial position of rotor estimation procedure and d axle positive direction judge information g _nSexperimental waveform.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

As shown in Figure 1, the invention provides a kind of surface-mount type permagnetic synchronous motor initial position detection method, specifically comprise the following steps:

Step 1), set up coordinate system graph of a relation, as shown in Figure 2, d-q is actual synchronization rotating coordinate system, for estimated rotor synchronous rotating frame, alpha-beta is actual two-phase rest frame, and defines Estimated Position Error wherein, θ is actual rotor initial position, for final initial position estimation value, initial value be 0.

Step 2), as shown in Figure 3, the q shaft current of estimated rotor synchronous rotating frame is given as 0, d shaft current and is given as a pulsating high frequency sinusoidal signal I _mhsin (ω _ht), wherein, I _mhfor injecting the amplitude of high-frequency current at d axle, ω _hfor injecting the angular frequency of high-frequency current at d axle, t represents current time.

Step 3), adoption rate resonant controller (PR) controls the d shaft current estimated and q shaft current, makes it consistent with given.

Step 4), to the voltage that PR adjuster exports with carry out Park inverse transformation, obtain the voltage u under the static alpha-beta coordinate system of two-phase _αand u _β, then adopt space vector pulse width modulation strategy to obtain six path switching signals of three-phase inverter, the mounted permagnetic synchronous motor SPMSM of table-drive.

Step 5), detect any biphase current in motor three-phase windings A/B/C, as shown in Figure 1, the present embodiment is chosen and is detected A phase and B phase current, first carry out Clarke conversion obtain the static alpha-beta coordinate system of two-phase under current i _αand i _β, then the d shaft current under Park conversion obtains estimated rotor synchronous rotating frame with q shaft current fed back to PR adjuster; In like manner, the same effect that also can realize this initial position detection method is detected to B phase and C phase, A phase and C phase current, just do not repeated here.

Step 6), the q shaft voltage of estimated rotor synchronous rotating frame is responded selecting frequency through band pass filter is ω _halternating current component be q shaft voltage response first harmonic component again with cosine signal cos (ω _ht) be multiplied and modulate, obtain DC component and frequency is 2 ω _halternating current component, eventually pass low pass filter filtering alternating current component, extract DC component, obtain estimated position deviation signal f _c(Δ θ).

Step 7), build position deviation closed loop, by estimated position deviation signal f _c(Δ θ) as the input of pi regulator, estimated rotor angular speed for the output of pi regulator, to estimated rotor angular speed integration obtains the rotor-position estimated, repeats step 2-7, until the rotor-position estimated converges to a steady state value, is the first estimated value of initial position of rotor

Step 8), as shown in Figure 4, first adopt band pass filter from the response of estimation d axle high frequency voltage in select the harmonic component of two times of Injection Signal frequencies time by itself and sinusoidal signal sin (2 ω _ht) be multiplied and modulate, then adopt low pass filter filtering high fdrequency component, extract DC component, obtain d axle square judgement information g _nS.According to g _nSsymbol decision d axle positive direction, if g _nSbe less than 0, then the N pole of d axle positive direction and magnetic pole in the same way, and the offset after d axle positive direction judges is 0, namely if g _nSbe greater than 0, then the N of d axle positive direction and magnetic pole is extremely reverse, and the offset after d axle positive direction judges is π, namely

As follows to the theory analysis of d axle positive direction determination methods:

For surface-mount type permagnetic synchronous motor, it is saturated that d shaft current works magnetic field when increasing magnetic action, and inductance reduces; When d shaft current plays demagnetizing effect, magnetic field is moved back saturated, and inductance increases.For simplifying the analysis, suppose that d shaft current is timing, inductance mean value is and remain unchanged; D shaft current is for time negative, and inductance mean value is according to the saturation characteristic of d axle inductance, obviously namely liu Ying, cycle, Zhao Chengliang, Deng. inject SPMSM low speed position Sensorless Control [J] based on pulsating high-frequency current. Chinese electrotechnics journal, 2012,7 (27): 139-145. give and inject pulsating high-frequency current after, permagnetic synchronous motor d shaft voltage response in the synchronous rotating frame estimated is:

${\hat{u}}_{\mathrm{dh}}=[Z+\mathrm{\Δ}Z\cos \left(2\mathrm{\Δ\θ}\right)]I_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)---\left(1\right)$

In formula, for average impedance, be half poor impedance, Z _d=r _s+ j ω _hl _dfor d axle high-frequency resistance, Z _q=r _s+ j ω _hl _qfor q axle high-frequency resistance, r _sfor stator resistance, L _dfor d axle inductance, L _qfor q axle inductance.

After completing first initial position estimation, position estimation error Δ θ is 0 or π, substitutes into formula (1) and obtains:

${\hat{u}}_{\mathrm{dh}}=Z_d{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)=(r_s+j{\mathrm{\ω}}_h{L}_d)I_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)=\sqrt{r_s^2+{\left({\mathrm{\ω}}_h{L}_d\right)}^2}{I}_{\mathrm{mh}}\sin ({\mathrm{\ω}}_{h}t+\arctan \frac{{\mathrm{\ω}}_h{L}_d}{r_s})---\left(2\right)$

First suppose that Δ θ is 0, consider the change of d axle inductance, formula (2) can do further arrangement:

${\hat{u}}_{\mathrm{dh}}=\left\{\begin{array}{c}\sqrt{r_s^2+{\left({\mathrm{\ω}}_h{L}_d^{+}\right)}^2}{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_h\text{t+arctan}\frac{{\mathrm{\ω}}_h{L}_d^{+}}{r_s}\right),t\∈(\frac{0+2\mathrm{k\π}}{{\mathrm{\ω}}_h},\frac{\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h})\\ \sqrt{r_s^2+{\left({\mathrm{\ω}}_h{L}_d^{-}\right)}^2}{I}_{\mathrm{mh}}\sin ({\mathrm{\ω}}_{h}t+\arctan \frac{{\mathrm{\ω}}_h{L}_d^{-}}{r_s}),t\∈(\frac{\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h},\frac{2\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h})\end{array}\right.---\left(3\right)$

Fourier expansion is carried out to formula (3), and the harmonic wave ignoring more than three times and three times obtains:

${\hat{u}}_{\mathrm{dh}}\left(t\right)=\frac{a_0}{2}+a_1\cos \left({\mathrm{\ω}}_{h}t\right)+b_1\sin \left({\mathrm{\ω}}_{h}t\right)+a_2\cos \left(2{\mathrm{\ω}}_{h}t\right)+b_2\sin \left(2{\mathrm{\ω}}_{h}t\right)---\left(4\right)$

According to Fourier series correlation theory, calculate the coefficient correlation in formula (4): a ₀=0, b ₁=r _si _mh, a ₂=0, these coefficients are substituted into formula (4) obtain:

${\hat{u}}_{\mathrm{dh}}\left(t\right)=\frac{{\mathrm{\ω}}_h(L_d^{+}+L_d^{-})I_{\mathrm{mh}}}{2}\cos \left({\mathrm{\ω}}_{h}t\right)+r_s{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)-\frac{4}{3\mathrm{\π}}(L_d^{-}-L_d^{+})I_{\mathrm{mh}}\sin \left(2{\mathrm{\ω}}_{h}t\right)---\left(5\right)$

From formula (5), because d axle inductance is with curent change, estimate that d shaft voltage exists second harmonic component, and the Δ θ of formula (5) correspondence is 0.If Δ θ is π, in like manner, formula (3) should change to:

${{\hat{u}}_{\mathrm{dh}}}^{*}=\left\{\begin{array}{c}\sqrt{r_s^2+{\left({\mathrm{\ω}}_h{L}_d^{-}\right)}^2}{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_h\text{t+arctan}\frac{{\mathrm{\ω}}_h{L}_d^{-}}{r_s}\right),t\∈(\frac{0+2\mathrm{k\π}}{{\mathrm{\ω}}_h},\frac{\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h})\\ \sqrt{r_s^2+{\left({\mathrm{\ω}}_h{L}_d^{+}\right)}^2}{I}_{\mathrm{mh}}\sin ({\mathrm{\ω}}_{h}t+\arctan \frac{{\mathrm{\ω}}_h{L}_d^{+}}{r_s}),t\∈(\frac{\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h},\frac{2\mathrm{\π}+2\mathrm{k\π}}{{\mathrm{\ω}}_h})\end{array}\right.---\left(6\right)$

Obviously, meet between formula (3) and formula (6):

${{\hat{u}}_{\mathrm{dh}}}^{*}\left(t\right)=-{\hat{u}}_{\mathrm{dh}}(t+\mathrm{\π}/{\mathrm{\ω}}_h)---\left(7\right)$

According to formula (5) and formula (7), when Δ θ is π, formula (5) should be rewritten as:

${{\hat{u}}_{\mathrm{dh}}}^{*}\left(t\right)=\frac{{\mathrm{\ω}}_h(L_d^{+}+L_d^{-})I_{\mathrm{mh}}}{2}\cos \left({\mathrm{\ω}}_{h}t\right)+r_s{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)-\frac{4}{3\mathrm{\π}}(L_d^{-}-L_d^{+})I_{\mathrm{mh}}\sin \left(2{\mathrm{\ω}}_{h}t\right)---\left(8\right)$

Contrast (5) and formula (8), when position estimation error Δ θ is 0, coefficient before second harmonic term in formula (5) is negative, when position estimation error Δ θ is π, coefficient before second harmonic term in formula (8) is just, defined function s (Δ θ):

$s\left(\mathrm{\Δ\θ}\right)=\left\{\begin{array}{cc}1,& \mathrm{\Δ\θ}=0\\ -1,& \mathrm{\Δ\θ}=\mathrm{\π}\end{array}\right.---\left(9\right)$

Then formula (5) and formula (8) can be collectively expressed as:

${\hat{u}}_{\mathrm{dh}}\left(t\right)=\frac{{\mathrm{\ω}}_h(L_d^{+}+L_d^{-})I_{\mathrm{mh}}}{2}\cos \left({\mathrm{\ω}}_{h}t\right)+r_s{I}_{\mathrm{mh}}\sin \left({\mathrm{\ω}}_{h}t\right)-\frac{4}{3\mathrm{\π}}(L_d^{-}-L_d^{+})I_{\mathrm{mh}}\sin \left(2{\mathrm{\ω}}_{h}t\right)---\left(10\right)$

From formula (10), estimate that the amplitude symbol of the second harmonic component of d axle high frequency voltage response is relevant to the judged result of d axle positive direction.If d axle positive direction and magnetic pole N pole are in the same way, i.e. Δ θ=0, then amplitude symbol is less than 0; If d axle positive direction and magnetic pole N are extremely reverse, i.e. Δ θ=π, then amplitude symbol is greater than 0.

For the correctness of checking institute extracting method, adopt matlab software to carry out and emulated and test based on hardware platform, specific as follows.

As shown in Fig. 5 (a) He Fig. 5 (b), when corresponding actual rotor initial position is 1rad, initial position estimation process and d axle positive direction judge information g _nSsimulation waveform.G _nSbe less than 0, represent d axle positive direction and magnetic pole N pole in the same way, without the need to first estimated position carry out angle compensation, θ _c=0; As shown in Fig. 5 (c) He Fig. 5 (d), when corresponding actual rotor initial position is 3rad, initial position estimation process and d axle positive direction judge information g _nSsimulation waveform.G _nSbe greater than 0, represent that d axle positive direction and magnetic pole N are extremely reverse, need to first estimated position compensate π radian, θ _c=π, final initial position estimation value is

As shown in Fig. 6 (a), when corresponding actual rotor initial position is 0.5rad, initial position estimation process and d axle positive direction judge information g _nSexperimental waveform.G _nSbe less than 0, represent d axle positive direction and magnetic pole N pole in the same way, without the need to first estimated position carry out angle compensation, θ _c=0; As shown in Fig. 6 (b), when corresponding actual rotor initial position is 4rad, initial position estimation process and d axle positive direction judge information g _nSsimulation waveform.G _nSbe greater than 0, represent that d axle positive direction and magnetic pole N are extremely reverse, need to first estimated position compensate π radian, θ _c=π, final initial position estimation value is

Claims (4)

1., based on the permagnetic synchronous motor initial position detection method that high-frequency current signal injects, it is characterized in that, comprise following steps:

Step 1), build rotor-position closed-loop regulating system based on pulsating high frequency current injection, obtain the first estimated value of rotor-position;

Step 2), extract the second harmonic component of d shaft voltage response, corresponding signal madulation is carried out to it, judges d axle positive direction, obtain the offset after the judgement of d axle positive direction;

Step 3), first for rotor-position estimated value is added the offset after the judgement of d axle positive direction, obtain final initial position estimation value.

2. the permagnetic synchronous motor initial position detection method injected based on high-frequency current signal according to claim 1, is characterized in that, the step obtaining the first estimated value of rotor-position is as follows:

Step 11), the q shaft current of estimated rotor synchronous rotating frame is given as 0, d shaft current and is given as a pulsating high frequency sinusoidal signal I _mhsin (ω _ht), wherein, I _mhfor injecting the amplitude of high-frequency current at d axle, ω _hfor injecting the angular frequency of high-frequency current at d axle, t represents current time;

Step 12), adoption rate resonant controller PR controls the d shaft current estimated and q shaft current, makes it consistent with given;

Step 13), the voltage that comparative example resonant controller PR exports with carry out Park inverse transformation, obtain the voltage u under the static alpha-beta coordinate system of two-phase _αand u _β, then adopt space vector pulse width modulation strategy to obtain six path switching signals of three-phase inverter, the mounted permagnetic synchronous motor of table-drive;

Step 14), detect any biphase current in motor three-phase windings A/B/C, first carry out Clarke conversion obtain the static alpha-beta coordinate system of two-phase under current i _αand i _β, then the d shaft current under Park conversion obtains estimated rotor synchronous rotating frame with q shaft current fed back to the input of ratio resonant controller;

Step 15), the q shaft voltage of estimated rotor synchronous rotating frame is responded selecting frequency through band pass filter is ω _halternating current component, be q shaft voltage response first harmonic component again with cosine signal cos (ω _ht) be multiplied and modulate, obtain DC component and frequency is 2 ω _halternating current component, eventually pass low pass filter filtering alternating current component, extract DC component, obtain estimated position deviation signal f _c(Δ θ);

Step 16), build position deviation closed loop, by estimated position deviation signal f _c(Δ θ) as the input of proportional and integral controller, estimated rotor angular speed for the output of proportional and integral controller, to estimated rotor angular speed integration obtains the rotor-position estimated;

Step 17), repeat step 11) to step 16), until the rotor-position estimated converges to a steady state value, be the first estimated value of initial position of rotor

3. the permagnetic synchronous motor initial position detection method injected based on high-frequency current signal according to claim 1, is characterized in that, described judgement d axle positive direction and obtain d axle positive direction judge after the detailed step of offset as follows:

Step 21), detect the d shaft voltage response of estimated rotor synchronous rotating frame it is first selected the second harmonic component of d shaft voltage response through band pass filter

Step 22), by second harmonic component with sinusoidal signal sin (2 ω _ht) be multiplied and modulate, obtain DC component and frequency is 4 ω _halternating current component, wherein ω _hfor injecting the angular frequency of high-frequency current signal at d axle, t represents current time;

Step 23), by the signal after modulation through low pass filter filtering alternating current component, extract DC component, this DC component is d axle positive direction and judges information g _nS.

4. the permagnetic synchronous motor initial position detection method injected based on high-frequency current signal according to claim 3, is characterized in that, according to g _nSsymbol decision d axle positive direction, if g _nSbe less than 0, then the N pole of d axle positive direction and magnetic pole in the same way, and the offset after d axle positive direction judges is 0; If g _nSbe greater than 0, then the N of d axle positive direction and magnetic pole is extremely reverse, and the offset after d axle positive direction judges is π.