CN103296960A - Vector control method for single current sensor - Google Patents

Abstract

The invention relates to a vector control method, in particular to a vector control method for a single current sensor, and solves the problem, that, after two current sensors of a converter comprising three current sensors fail, current decoupling transformation cannot be achieved by the traditional vector control method. According to the method, stator current and rotor flux linkage can be measured through one current signal and stator voltage vector by a single current sensor state observer; the observed stator current is used as current feedback for closed current loop; rotating speed measured by a code disc is used as speed feedback for closed speed loop; a current loop PI regulator outputs stator voltage which is modulated by SVPWM (space vector pulse width modulation) to generate six IGBT (insulated gate bipolar transistor) drive signals; accordingly, the inverter is driven to drive a motor to operate. The vector control method for the single current sensor is applicable to fault-tolerant control after two current sensors fail.

Description

Single current sensor vector control method

Technical Field

The invention relates to a vector control method, in particular to a vector control method of a single current sensor.

Background

Current universal frequency converters typically use three or two current sensors to accomplish current sampling. When three or two current sensors are adopted in the frequency converter, the vector control schematic block diagram is shown in figure 1, wherein omega in figure 1_refAnd ω_rRespectively given speed and actual speed of the rotor of the motor, i^* _sdAnd i^* _sqRespectively a stator d-axis current given value and a stator q-axis current given value, i_sdAnd i_sqD-axis current feedback quantity and q-axis current feedback quantity, i, of motor stator_sαAnd i_sβThe measured values are the stator alpha axis current and the stator beta axis current under the static alpha beta coordinate system. As can be seen from figure 1, the control system adopts an indirect magnetic field orientation vector control method with a speed sensor, and the difference between the given rotating speed and the feedback rotating speed measured by a code disc is regulated by a speed loop PI to obtain a given value i of the current of a stator q axis^* _sqStator d-axis reference value i^* _sdDirectly giving; measuring stator current i with a current sensor_a、i_bAnd i_cRespectively obtaining a stator d-axis current feedback value i through Clark and Park conversion_sdAnd a stator q-axis current feedback value i_sqD-axis current feedback value i of stator_sdAnd a stator q-axis current feedback value i_sqThe difference between the feedback values and the respective feedback values is respectively obtained by a current loop PI regulator to obtain a given value u of the stator d-axis voltage^* _sdAnd stator q-axis voltage given quantity u^* _sqAnd then obtaining a stator alpha axis voltage component u through Park inverse transformation^* _sαAnd stator beta axis voltage component u^* _sβThen, a driving signal of 6 paths of switching tubes is generated through SVPWM, and finally, the 6 paths of signals are used for driving a frequency converter to enable the motor to rotate.

When one of the three current sensors fails, the closed-loop control of the system can be realized by using the existing fault-tolerant control method, and the basic idea is as follows: the sum of the three-phase currents is always zero, the three-phase current is reconstructed by utilizing the two-phase currents, then the three-phase current is subjected to coordinate transformation, and finally closed-loop control of the system is realized. However, when two of the three current sensors fail, the traditional vector control method cannot realize decoupling transformation of current, and finally cannot realize closed-loop control of the system.

Disclosure of Invention

The invention aims to solve the problem that the traditional vector control method cannot realize the decoupling transformation of current after two current sensors of a frequency converter containing three current sensors have faults.

The single current sensor vector control method of the present invention,

the vector control method is realized by measuring any phase current of the stator based on a single current sensor, taking the single current sensor to measure the phase current a of the stator as an example, and comprises the following steps:

the method comprises the following steps: measuring DC bus voltage V using voltage sensor_DCReconstructing stator three-phase voltage u according to the SVPWM modulation output 6 circuit IGBT driving signal at the current moment_A、u_BAnd u_CAnd measuring stator a-phase current i by using a current sensor_α；

Step two: the stator three-phase voltage u obtained in the step one is converted by Clark_A、u_B、u_CAnd stator a phase current i_αTransforming the static three-phase coordinate system into a static alpha beta coordinate system to obtain the stator voltage under the static alpha beta coordinate system:

i_Sα＝i_a

$\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]$

wherein u is_sαStator voltage u for the alpha axis in a stationary alpha beta coordinate system_sβStator voltage i for the beta axis in a stationary alpha beta coordinate system_sαStator of alpha axis under static alpha beta coordinate systemCurrent flow;

step three: the stator voltage u under the static alpha beta coordinate system obtained in the step two_sαStator voltage u_sβAnd stator current i_sαThe state observer is sent to the state observer of the single current sensor to realize state observation and obtain a stator alpha axis current observed valueAnd stator beta axis current observed value

Step four: stator alpha axis current observed value obtained by state observer in step three

And stator beta axis current observed value

Obtaining stator d-axis current feedback quantity i through Park conversion_sdAnd stator q-axis current feedback quantity i_sqThe transformation formula is as follows:

$\left(\begin{array}{c}{i}_{\mathrm{sd}}\\ i_{\mathrm{sq}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{\hat{i}}_{\mathrm{s\α}}\\ {\hat{i}}_{\mathrm{s\β}}\end{array}\right)$

step five: method for measuring actual rotating speed omega of motor rotor by adopting photoelectric code disc_rAccording to the actual rotation speed omega_rStator d-axis current feedback quantity i_sdAnd stator q-axis current feedback quantity i_sqCalculating to obtain a magnetic chain angle theta by using an indirect magnetic field orientation method;

step six: given rotation speed omega of motor rotor_refAnd the actual rotational speed omega of the motor rotor_rThe difference value is regulated by a speed ring PI regulator to obtain a stator q-axis current given value i^* _sq；

Step seven: set stator d-axis current set value i^* _sdAnd stator d-axis current feedback quantity i_sdThe difference value of the d-axis voltage of the stator is obtained by a current loop PI regulator to obtain a given value u of the d-axis voltage of the stator^* _sdStator q-axis current set value i^* _sqFeedback quantity i of q-axis current of stator_sqThe difference value of the voltage of the q axis of the stator is obtained by a current loop PI regulator to obtain a given quantity u of the voltage of the q axis of the stator^* _sq；

Step eight: stator d-axis voltage given quantity u^* _sdAnd stator q-axis voltage given quantity u^* _sqRespectively obtaining stator alpha axis voltage components u under a static alpha beta coordinate system through Park inverse transformation^* _sαAnd stator beta axis voltage component u^* _sβ：

$\left(\begin{array}{c}{u^{*}}_{\mathrm{s\α}}\\ {u^{*}}_{\mathrm{s\β}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{u^{*}}_{\mathrm{sd}}\\ {u^{*}}_{\mathrm{sq}}\end{array}\right)$

Step nine: stator alpha axis voltage component u under the static alpha beta coordinate system^* _sαStator beta axis voltage component u^* _sβAnd the flux linkage angle theta is modulated by SVPWM to output 6 paths of IGBT driving signals, and the 6 paths of IGBT driving signals drive an inverter to obtain motor driving signals to realize motor control.

The invention has the advantages that the stator current vector and the rotor flux linkage are observed by detecting the stator one-phase current and the stator voltage and utilizing the single current sensor state observer, and finally the closed-loop control of the system is realized. The invention reduces the dependency of the vector control system on the current sensor and improves the fault tolerance of the control system on the current sensor.

Drawings

FIG. 1 is a schematic diagram illustrating a conventional vector control method with a speed sensor.

FIG. 2 is a schematic diagram illustrating the vector control method of the single current sensor according to the present invention.

Fig. 3 is a schematic diagram of a principle of implementing an observation state of the state observer according to the third embodiment.

Fig. 4 is a schematic diagram of a waveform of the rotating speed of the motor under the control of the vector control method of the single current sensor.

Fig. 5 is a schematic waveform diagram of a phase current of a stator a of a motor under the control of the single current sensor vector control method according to the invention.

Detailed Description

The first embodiment is as follows: the present embodiment, the single current sensor vector control method according to the present embodiment, will be described with reference to fig. 1,

the vector control method is realized by measuring any phase current of the stator based on a single current sensor, taking the single current sensor to measure the phase current a of the stator as an example, and comprises the following steps:

the method comprises the following steps: measuring DC bus voltage V using voltage sensor_DCReconstructing stator three-phase voltage u according to the SVPWM modulation output 6 circuit IGBT driving signal at the current moment_A、u_BAnd u_CAnd measuring stator a-phase current i by using a current sensor_α；

Step two: the stator three-phase voltage u obtained in the step one is converted by Clark_A、u_B、u_CAnd stator a phase current i_αTransforming the static three-phase coordinate system into a static alpha beta coordinate system to obtain the stator voltage under the static alpha beta coordinate system:

i_Sα＝i_a

$\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]$

wherein u is_sαStator voltage u for the alpha axis in a stationary alpha beta coordinate system_sβStator voltage i for the beta axis in a stationary alpha beta coordinate system_sαStator current of an alpha axis under a static alpha beta coordinate system;

step three: the stator voltage u under the static alpha beta coordinate system obtained in the step two_sαStator voltage u_sβAnd stator current i_sαThe state observer is sent to the state observer of the single current sensor to realize state observation and obtain a stator alpha axis current observed valueAnd stator beta axis current observed value

Step four: stator alpha axis current observed value obtained by state observer in step threeAnd stator beta axis current observed value

Obtaining stator d-axis current feedback quantity i through Park conversion_sdAnd stator q-axis current feedback quantity i_sqThe transformation formula is as follows:

$\left(\begin{array}{c}{i}_{\mathrm{sd}}\\ i_{\mathrm{sq}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{\hat{i}}_{\mathrm{s\α}}\\ {\hat{i}}_{\mathrm{s\β}}\end{array}\right)$

step five: method for measuring actual rotating speed omega of motor rotor by adopting photoelectric code disc_rAccording to the actual rotation speed omega_rStator d-axis current feedback quantity i_sdAnd stator q-axis current feedback quantity i_sqCalculating to obtain a magnetic chain angle theta by using an indirect magnetic field orientation method;

step six: given rotation speed omega of motor rotor_refAnd the actual rotational speed omega of the motor rotor_rThe difference value is regulated by a speed ring PI regulator to obtain a stator q-axis current given value i^* _sq；

Step seven: set stator d-axis current set value i^* _sdAnd stator d-axis current feedback quantity i_sdThe difference value of the d-axis voltage of the stator is obtained by a current loop PI regulator to obtain a given value u of the d-axis voltage of the stator^* _sdStator q-axis current set value i^* _sqFeedback quantity i of q-axis current of stator_sqThe difference value of the voltage of the q axis of the stator is obtained by a current loop PI regulator to obtain a given quantity u of the voltage of the q axis of the stator^* _sq；

Step eight: stator d-axis voltage given quantity u^* _sdAnd stator q-axis voltage given quantity u^* _sqRespectively obtaining stator alpha axis voltage components u under a static alpha beta coordinate system through Park inverse transformation^* _sαAnd stator beta axis voltage component u^* _sβ：

$\left(\begin{array}{c}{u^{*}}_{\mathrm{s\α}}\\ {u^{*}}_{\mathrm{s\β}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{u^{*}}_{\mathrm{sd}}\\ {u^{*}}_{\mathrm{sq}}\end{array}\right)$

Step nine: stator alpha axis voltage component u under the static alpha beta coordinate system^* _sαStator beta axis voltage component u^* _sβAnd the flux linkage angle theta is modulated by SVPWM to output 6 paths of IGBT driving signals, and the 6 paths of IGBT driving signals drive an inverter to obtain motor driving signals to realize motor control.

In the embodiment, the stator voltage and a certain phase current of the stator are detected and sent to the single current sensor state observer, so that the state observation of the stator current and the rotor flux linkage is realized, and the closed-loop control of the system is further realized.

The vector control can be realized by detecting only one phase current signal in the embodiment.

The second embodiment is as follows: the present embodiment will be described with reference to fig. 3, which is a further limitation of the single current sensor vector control method described in the first embodiment,

obtaining the alpha axis current vector of the stator in the third step

And stator beta axis current vector

The method comprises the following steps:

step three, firstly: observing the alpha axis current of the stator in the state observer

And the actually measured alpha axis current value of the statorSubtracting to obtain a current error e;

step three: according to the formula

Obtaining stator current observation state quantity

Derivative of (2)

Then on the derivative

Integral calculation of stator current observation state quantity

In the formula:

$A=\left[\begin{array}{cccc}{a}_{11}& 0& a_{13}& a_{14}{\mathrm{\ω}}_r\\ 0& a_{11}& -a_{14}{\mathrm{\ω}}_r& a_{13}\\ a_{31}& 0& a_{33}& -{\mathrm{\ω}}_r\\ 0& a_{31}& {\mathrm{\ω}}_r& a_{33}\end{array}\right];$

$\hat{x}=\left[\begin{array}{c}{\hat{i}}_{\mathrm{s\α}}\\ {\hat{i}}_{\mathrm{s\β}}\\ {\widehat{\mathrm{\ψ}}}_{\mathrm{r\α}}\\ {\widehat{\mathrm{\ψ}}}_{\mathrm{r\β}}\end{array}\right];$

$B={\left[\begin{array}{cccc}b& 0& 0& 0\\ 0& b& 0& 0\end{array}\right]}^T;$

$u=\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right];$

$\mathrm{\σ}=\frac{L_s{L}_r-L_m^2}{L_s{L}_r};$

$a_{11}=-\frac{R_r{L}_m^2+R_s{L}_r^2}{\mathrm{\σ}{L}_s{L}_r^2};$

$a_{13}=\frac{L_m{R}_r}{\mathrm{\σ}{L}_s{L}_r^2};$

$a_{14}=\frac{L_m}{\mathrm{\σ}{L}_s{L}_r};$

$a_{31}=\frac{L_m{R}_r}{L_r};$

$a_{33}=-\frac{R_r}{L_r};$

$b=\frac{1}{{\mathrm{\σL}}_s};$

a stator alpha axis current observation observed by a state observer,

a stator beta axis current observation observed by a state observer,

the observed component of the alpha axis of the rotor flux linkage observed by the state observer,

beta-axis observed component, L, of rotor flux linkage observed by a state observer_sFor equivalent self-inductance of the stator, L_rFor equivalent self-inductance of the rotor, L_mThe mutual inductance of the stator and the rotor is adopted, and sigma is a magnetic leakage coefficient; r_rIs rotor resistance, R_sIs a stator resistor;

the matrix G is: $G=\left[\begin{array}{c}{f}_1+f_2\mathrm{sign}(\·)\\ 0\\ g_1+g_2\mathrm{sign}(\·)\\ 0\end{array}\right],$

f₁as a proportional gain of current, f₂Gain as a function of current sign; g₁Proportional gain of flux linkage, g₂Sign () is a sign function for flux linkage sign function gain;

step three: observing state quantity of stator current obtained in the third step and the second step

Multiplying the output matrix C to obtain an observed value of the alpha axis current of the observed stator

And observing the observed value of the stator beta axis current

The stator current of the observation state quantity obtained in the third step and the second step

Multiplying the output matrix D to obtain an alpha-axis observation component of the rotor flux linkage

And the beta-axis observed component of the rotor flux linkage

Wherein, $C=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right],$ $D=\left[\begin{array}{cccc}0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right].$

the state observer is used for observing stator current and rotor flux linkage under a static alpha beta coordinate system.

The basic idea of the single current sensor state observer is as follows: the alpha axis of a static alpha beta coordinate system is oriented on a certain measured phase current vector, all detectable current errors are introduced to the alpha axis, and the current value of the alpha beta axis of the stator in the static coordinate system is observed by a state observer. Error is not introduced when the beta axis current value is observed, but when the alpha axis current value observed by the control system gradually converges to a true value, the value obtained by each parameter of the beta axis through a complete observation method also gradually converges to the true value.

The third concrete implementation mode: this embodiment is a further limitation of the single current sensor vector control method described in the first embodiment,

in the fifth step, a magnetic chain angle theta is calculated by using an indirect magnetic field orientation method:

θ＝∫ω_sdt，

in the above formula:

${\mathrm{\ω}}_s={\mathrm{\ω}}_r+\frac{i_{\mathrm{sq}}}{T_r\·i_{\mathrm{sd}}}$

wherein, T_rIs the rotor time constant.

The experiment of the invention for realizing the closed-loop control of the system by using the a-phase current is carried out, the rated voltage of the motor is 380V, the rated power is 1.1kW, the rated rotating speed is 1400rpm, the given frequency is 20Hz, and the experimental result is shown in fig. 4 and 5.

Experimental results prove that the single current sensor vector control method can realize closed-loop control of a system and can be used as a fault-tolerant control method after a current sensor fails.

Claims (3)

1. The single current sensor vector control method is characterized in that the vector control method is realized by measuring any phase current of a stator based on a single current sensor, taking the single current sensor to measure the phase current of the stator a as an example, and the method comprises the following steps:

the method comprises the following steps: measuring DC bus voltage V using voltage sensor_DCReconstructing stator three-phase voltage u according to the SVPWM modulation output 6 circuit IGBT driving signal at the current moment_A、u_BAnd u_CAnd measuring stator a-phase current i by using a current sensor_α；

Step two: the stator three-phase voltage u obtained in the step one is converted by Clark_A、u_B、u_CAnd stator a phase current i_αTransforming the static three-phase coordinate system into a static alpha beta coordinate system to obtain the stator voltage under the static alpha beta coordinate system:

i_Sα＝i_a

$\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]$

wherein u is_sαStator voltage u for the alpha axis in a stationary alpha beta coordinate system_sβStator voltage i for the beta axis in a stationary alpha beta coordinate system_sαStator current of an alpha axis under a static alpha beta coordinate system;

step three: the stator voltage u under the static alpha beta coordinate system obtained in the step two_sαStator voltage u_sβAnd stator current i_sαThe state observer is sent to the state observer of the single current sensor to realize state observation and obtain a stator alpha axis current observed value

And stator beta axis current observed value

Step four: stator alpha axis current observed value obtained by state observer in step three

And stator beta axis current observed value

Obtaining stator d-axis current feedback quantity i through Park conversion_sdAnd stator q-axis current feedback quantity i_sqThe transformation formula is as follows:

$\left(\begin{array}{c}{i}_{\mathrm{sd}}\\ i_{\mathrm{sq}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{\hat{i}}_{\mathrm{s\α}}\\ {\hat{i}}_{\mathrm{s\β}}\end{array}\right)$

step five: method for measuring actual rotating speed omega of motor rotor by adopting photoelectric code disc_rAccording to the actual rotation speed omega_rStator d-axis current feedback quantity i_sdAnd stator q-axis current feedback quantity i_sqCalculating to obtain a magnetic chain angle theta by using an indirect magnetic field orientation method;

step six: given rotation speed omega of motor rotor_refAnd the actual rotational speed omega of the motor rotor_rThe difference value is regulated by a speed ring PI regulator to obtain a stator q-axis current given value i^* _sq；

Step seven: set stator d-axis current set value i^* _sdAnd stator d-axis current feedback quantity i_sdThrough the current loop PIThe regulator obtains a given quantity u of stator d-axis voltage^* _sdStator q-axis current set value i^* _sqFeedback quantity i of q-axis current of stator_sqThe difference value of the voltage of the q axis of the stator is obtained by a current loop PI regulator to obtain a given quantity u of the voltage of the q axis of the stator^* _sq；

Step eight: stator d-axis voltage given quantity u^* _sdAnd stator q-axis voltage given quantity u^* _sqRespectively obtaining stator alpha axis voltage components u under a static alpha beta coordinate system through Park inverse transformation^* _sαAnd stator beta axis voltage component u^* _sβ：

$\left(\begin{array}{c}{u^{*}}_{\mathrm{s\α}}\\ {u^{*}}_{\mathrm{s\β}}\end{array}\right)=\left(\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right)\left(\begin{array}{c}{u^{*}}_{\mathrm{sd}}\\ {u^{*}}_{\mathrm{sq}}\end{array}\right)$

Step nine: stator alpha axis voltage component u under the static alpha beta coordinate system^* _sαStator beta axis voltage component u^* _sβAnd the flux linkage angle theta is modulated by SVPWM to output 6 paths of IGBT driving signals, and the 6 paths of IGBT driving signals drive an inverter to obtain motor driving signals to realize motor control.

2. The single current sensor vector control method of claim 1,

obtaining the alpha axis current vector of the stator in the third step

And stator beta axis current vector

The method comprises the following steps:

step three, firstly: observing the alpha axis current of the stator in the state observer

And the actually measured alpha axis current value i of the stator_sαSubtracting to obtain a current error e;

step three: according to the formula

Obtaining stator current observation state quantity

Derivative of (2)

Then on the derivative

Integral calculation of stator current observation state quantity

In the formula:

$A=\left[\begin{array}{cccc}{a}_{11}& 0& a_{13}& a_{14}{\mathrm{\ω}}_r\\ 0& a_{11}& -a_{14}{\mathrm{\ω}}_r& a_{13}\\ a_{31}& 0& a_{33}& -{\mathrm{\ω}}_r\\ 0& a_{31}& {\mathrm{\ω}}_r& a_{33}\end{array}\right];$

$\hat{x}=\left[\begin{array}{c}{\hat{i}}_{\mathrm{s\α}}\\ {\hat{i}}_{\mathrm{s\β}}\\ {\widehat{\mathrm{\ψ}}}_{\mathrm{r\α}}\\ {\widehat{\mathrm{\ψ}}}_{\mathrm{r\β}}\end{array}\right];$

$B={\left[\begin{array}{cccc}b& 0& 0& 0\\ 0& b& 0& 0\end{array}\right]}^T;$

$u=\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right];$

$\mathrm{\σ}=\frac{L_s{L}_r-L_m^2}{L_s{L}_r};$

$a_{11}=-\frac{R_r{L}_m^2+R_s{L}_r^2}{\mathrm{\σ}{L}_s{L}_r^2};$

$a_{13}=\frac{L_m{R}_r}{\mathrm{\σ}{L}_s{L}_r^2};$

$a_{14}=\frac{L_m}{\mathrm{\σ}{L}_s{L}_r};$

$a_{31}=\frac{L_m{R}_r}{L_r};$

$a_{33}=-\frac{R_r}{L_r};$

$b=\frac{1}{{\mathrm{\σL}}_s};$

a stator alpha axis current observation observed by a state observer,

a stator beta axis current observation observed by a state observer,

the observed component of the alpha axis of the rotor flux linkage observed by the state observer,

beta-axis observed component, L, of rotor flux linkage observed by a state observer_sFor equivalent self-inductance of the stator, L_rFor equivalent self-inductance of the rotor, L_mThe mutual inductance of the stator and the rotor is adopted, and sigma is a magnetic leakage coefficient; r_rIs rotor resistance, R_sIs a stator resistor;

the matrix G is: $G=\left[\begin{array}{c}{f}_1+f_2\mathrm{sign}(\·)\\ 0\\ g_1+g_2\mathrm{sign}(\·)\\ 0\end{array}\right],$

f₁as a proportional gain of current, f₂Gain as a function of current sign; g₁Proportional gain of flux linkage, g₂Sign () is a sign function for flux linkage sign function gain;

step three: observing state quantity of stator current obtained in the third step and the second step

Multiplying the output matrix C to obtain an observed value of the alpha axis current of the observed stator

And observing the observed value of the stator beta axis current

The stator current of the observation state quantity obtained in the third step and the second step

Multiplying the output matrix D to obtain an alpha-axis observation component of the rotor flux linkage

And the beta-axis observed component of the rotor flux linkage

Wherein, $C=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right],$ $D=\left[\begin{array}{cccc}0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right].$

3. the single current sensor vector control method of claim 1,

in the fifth step, a magnetic chain angle theta is calculated by using an indirect magnetic field orientation method:

θ＝∫ω_sdt，

in the above formula:

${\mathrm{\ω}}_s={\mathrm{\ω}}_r+\frac{i_{\mathrm{sq}}}{T_r\·i_{\mathrm{sd}}}$

wherein, T_rIs the rotor time constant.

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