CN104201956B - Asynchronous motor direct torque control devices and methods therefor - Google Patents

Abstract

Asynchronous motor direct torque control device provided by the invention, comprise high-voltage asynchronous motor and high-pressure matrix frequency converter, high-pressure matrix frequency converter comprises phase shift isolating transformer, matrixing cell array and master controller, phase shift isolating transformer has 3n three-phase secondary winding, and matrixing cell array lines up the capable array of 3 row × n by 3n matrixing power cell.Matrixing power cell adopts Z source-matrixing power cell.Present invention also offers the method for direct torque control, comprise and obtain rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}step, obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _estep, obtain voltage state signal S _aN, S _bN, S _cNwith the stator voltage vector of correspondence step and the final step controlling the rotating speed of motor.Its advantage is: improve voltage transmission than and the reliability of inversion, work safety, stable, cost is low, and volume is little, and the life-span is long, and its input can double-direction control, achieve method simply, reliable asynchronous motor direct torque control.

Description

Asynchronous motor direct torque control devices and methods therefor

Technical field

The present invention relates to electric motor system and control method thereof, particularly a kind of asynchronous motor direct torque control devices and methods therefor.

Background technology

High-voltage high-power motor is widely used in the fields such as petrochemical industry, cement manufacture, mining, metallurgy, transport, electric power, papermaking and steel rolling.Frequency converter is the visual plant of lifting motor system energy efficiency, but industrial circle is still in the starting stage for the energy-conservation of high-voltage high-power motor or high performance variable frequency speed regulation at present, and this development level that is main and high voltage converter is closely related.

High-voltage frequency conversion and speed-adjusting adopts step down and step up transformer to realize the mapping mode of high-low-high the earliest, and its essence is still low voltage frequency converter.There is Gao-high direct-type high voltage converter afterwards, according to or without intermediate DC link, AC-DC-AC and friendship-hand over two class frequency converters can be divided into.Present stage, the high voltage converter of Application comparison maturation is AC-DC-AC type multi-level frequency conversion device.For ac-dc-ac frequency converter, according to the difference of DC link filter element, current source type variable frequency device and voltage-source type frequency converter can be divided into, wherein adopt the application of the voltage-source type of bulky capacitor filtering the most general with DC link.High-tension electricity die mould frequency converter mainly adopts multilevel technology, and its main flow topological structure is clamper type and cascade connection type, modularization three major types.Multilevel technology can avoid the direct series connection of device for power switching, has the advantages such as harmonic content is low, voltage change ratio is little, device for power switching stress is little, switching loss is little.But also there are some problems to need to solve: side harmonics pollutes; Four quadrant running can not easily be realized; Lower input power factor, efficiency of transmission reduces, and place capacity increases, and voltage stability is deteriorated.

In recent years, AC-AC matrix converter is more and more subject to the extensive concern of Chinese scholars with the series of advantages that AC-DC-AC is incomparable, as: without intermediate DC link, compact conformation, be convenient to modularized design, four quadrant running can be realized, control freedom degree is large, the amplitude of output voltage and frequency range continuously adjustabe, input power factor is controlled, and dynamic response is fast.Matrix converter a kind ofly adopts pulse-width modulation to obtain the power-converting device of desired output voltage based on bidirectional switch.Direct matrix transform device and indirect matrix converter can be divided into by topological structure.Publication number is that the patent of CN102545644 proposes a kind of matrix and hands over-hand over high voltage converter topological structure, as shown in Figure 1, adopts H bridge power unit as shown in Figure 2 to replace the bidirectional switch of direct converter, forms multi-level matrix frequency converter.It is low that this kind of high-pressure matrix frequency converter has cost, and volume is little, and the life-span is long, can realize the advantages such as four-quadrant operation, but because the restriction of power model self character, make frequency converter occur complex structure, and voltage transmission is than low, and the change of current is complicated, the shortcomings such as reliability is low.

For the problems referred to above, publication number is that the patent of CN101013856 proposes cascaded multiple matrix converter topological structure, and as shown in Figure 3, its power cell adopts the rectification stage of bipolar matrix converter as shown in Figure 4.Publication number is that the patent of CN103178720 proposes high-pressure matrix frequency converter topological structure, as shown in Figure 5, devises two kinds of power model types, wherein a kind of be as shown in Figure 6 be three-phase-single-phase bipolar matrix converter module.Bipolar matrix converter is all relate in above-mentioned publication number CN101013856 and publication number CN103178720 two kinds of high-pressure matrix frequency converters.Dual stage matrix converter belongs to a class topological structure of indirect matrix converter.The common bipolar matrix converter of three-phase-three-phase, as shown in Figure 7, it comprises rectification stage circuit based on bidirectional switch and common inverse cascade circuit, does not comprise the intermediate dc energy-storage travelling wave tube such as bulky capacitor or large inductance.Rectification stage circuit is made up of 6 bidirectional switchs, and inverse cascade circuit is identical with traditional three-phase full-bridge inverter structure.The shortcomings such as this dual stage matrix converter not only functionally can compare favourably with traditional matrix converter, and the control that can overcome classical matrix formula converter is complicated, change of current difficulty are a kind of novel A-A transducers having very much development potentiality.But the voltage transmission of bipolar matrix converter is lower, there is the deficiencies such as change of current dead band and poor reliability, it is a major reason of restriction matrix formula converter development always.

Meanwhile, according to manufacturing technique requirent, finally reach in the Optimal Control of motor speed and the task of adjustment, realize asynchronous motor direct torque control, also face all difficulties.Subject matter is the synthetic technology of inverter space vector, and the determination of its selection mode.The reliable Direct Torque Control of research high-voltage asynchronous motor is a major subjects of its high performance control.

Summary of the invention

The object of the invention is to overcome above-mentioned defect, high-voltage asynchronous motor direct torque control devices and methods therefor is provided, provide the high-voltage matrix converter of the reliability that can improve voltage transmission ratio and inversion, simple, the reliable asynchronous motor direct torque control of implementation method.

For achieving the above object, asynchronous motor direct torque control device provided by the invention, comprise asynchronous motor, also comprise high-pressure matrix frequency converter, described high-pressure matrix frequency converter comprises phase shift isolating transformer, matrixing cell array and master controller, wherein: described phase shift isolating transformer has 3n three-phase secondary winding, n is natural number, every 3 secondary winding are one group and have identical phase place, secondary winding is respectively organized phase place and is increased progressively successively, initial phase is 0 °, and between adjacent, phase difference is 60/n degree; Three-phase high-voltage alternating current by described phase shift isolating transformer with 3 multiple array export, for described matrixing cell array is powered; Described matrixing cell array comprises 3n matrixing power cell, line up 3 row × n capable, it is capable corresponding that described phase shift isolating transformer secondary winding is respectively organized respectively with array, 3 secondary winding often in group respectively with often row in 3 described matrixing power cell one_to_one corresponding be connected, in described matrixing cell array, each power take-off arranging described matrixing power cell is connected successively, and three row of described matrixing power cell export and adopt Y connection to form three-phase alternating voltage output;

Described matrixing power cell is Z source-matrixing power cell, wherein prime rectifier is 3H bridge construction, comprise 3 brachium pontis, input three-phase alternating voltage, export two-way direct voltage, rear class inverter is 2H bridge construction, comprise 2 brachium pontis, input two-way direct voltage, output single-phase alternating voltage, is connected with Z source network between prime rectifier and rear class inverter, described Z source network is by the first inductance, second inductance, the X-type Z source network of the first electric capacity and the second electric capacity composition, as the first input end of Z source network after one end of described first electric capacity is connected with one end of described first inductance, as the first output of Z source network after the other end of described first inductance is connected with one end of described second electric capacity, as the second input of Z source network after the other end of described second electric capacity is connected with one end of described second inductance, as the second output of Z source network after the other end of described second inductance is connected with the other end of described first electric capacity, the first input end of described Z source network is connected with the output of the second input with rectification stage circuit, first output of Z source network is connected with the input of the second output with inverse cascade circuit,

Described each matrixing power cell is connected with a sub-controller respectively, and described master controller is connected with each described matrixing unit and each sub-controller respectively by signal optical fibre, and the step that described master controller performs direct torque control comprises:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β};

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e;

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cN, according to S _aN, S _bN, S _cNthe switch motion controlling converter inverse cascade obtains corresponding stator voltage vector

Step 4 is by controlling and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

Asynchronous motor direct torque control device of the present invention, wherein said matrixing power cell also comprises input filter, described input filter is made up of three filter resistances and three filter capacitors, three described filter resistance one end are connected with the input of matrixing power cell respectively, the other end of three described filter resistances is corresponding with one end of three described filter capacitors respectively connects, and the other end of three described filter capacitors is interconnected.

Asynchronous motor direct torque control device of the present invention, in wherein said step 1, utilizes formula (1) and formula (2) to stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _ccarry out 3/2 conversion:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

Asynchronous motor direct torque control device of the present invention, in wherein said step 2, utilizes formula (3) and formula (4) by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain the stator magnetic linkage ψ of motor _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

Asynchronous motor direct torque control device of the present invention, in wherein said step 3, utilizes formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$

For achieving the above object, asynchronous motor direct torque control method provided by the invention, the method comprises the following steps:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β};

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e;

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cN, according to S _aN, S _bN, S _cNthe switch motion controlling converter inverse cascade obtains corresponding stator voltage vector

Step 4 is by controlling and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

Asynchronous motor direct torque control method of the present invention, in wherein said step 1, utilizes formula (1) and formula (2) to stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _ccarry out 3/2 conversion:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

Asynchronous motor direct torque control method of the present invention, in wherein said step 2, utilizes formula (3) and formula (4) by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

Asynchronous motor direct torque control method of the present invention, in wherein said step 3, utilizes formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$

Advantage and the good effect of asynchronous motor direct torque control devices and methods therefor of the present invention are: owing to have employed high-voltage matrix converter, improve the voltage transmission ratio of matrix converter, improve the reliability of inverter, cost is low, volume is little, life-span is long, frequency converter work safety, stable, and input can double-direction control, energy capable of bidirectional flowing, is easy to the four quadrant running realizing motor.Simultaneously, carry out switch to the inverse cascade of high-voltage matrix converter to select to control, space vector of voltage required for synthesis, achieve asynchronous motor direct torque control, its method controlled is simple, reliable, according to manufacturing technique requirent, can finally reach the Optimal Control to motor speed and adjustment.

Be described in detail with reference to accompanying drawing below in conjunction with embodiment.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of high pressure multilevel matrix converter;

Fig. 2 is the circuit diagram of high pressure multilevel matrix converter breaker in middle unit;

Fig. 3 is the circuit diagram of cascaded multiple high-pressure matrix frequency converter;

Fig. 4 is the circuit diagram of Fig. 3 cascade multiple high-voltage matrix frequency converter breaker in middle unit;

Fig. 5 is a kind of circuit diagram of high-pressure matrix frequency converter;

Fig. 6 is the circuit diagram of Fig. 5 mesohigh matrix frequency converter breaker in middle unit;

Fig. 7 is the circuit diagram of bipolar matrix converter;

Fig. 8 is the circuit structure diagram of mesohigh matrix frequency converter of the present invention;

Fig. 9 is the circuit structure diagram of Z source-matrix converter power cell in mesohigh matrix frequency converter of the present invention;

Figure 10 is the structural representation of the asynchronous motor adopting high-pressure matrix inverter supply;

Figure 11 is the circuit diagram of the matrix converter power cell of A phase;

Figure 12 is space vector of voltage schematic diagram;

Figure 13 is the schematic diagram of six-arm dipmeter and voltage and β coordinate system;

Figure 14 is the space vector of voltage schematic diagram of direct torque control switching signal;

Figure 15 is the flow chart of asynchronous motor direct torque control.

Embodiment

Asynchronous motor direct torque control device of the present invention, with reference to Figure 10, comprises asynchronous motor and high-pressure matrix frequency converter, and with reference to Fig. 8, three outputs U, V, W by high-pressure matrix frequency converter are connected with an asynchronous motor.High-pressure matrix frequency converter comprises phase shift isolating transformer, matrixing cell array and master controller, wherein:

1) phase shift isolating transformer

With reference to Fig. 8, phase shift isolating transformer has 3n three-phase secondary winding, and n is natural number, and every 3 secondary winding are one group and have identical phase place, and secondary winding is respectively organized phase place and increased progressively successively, and initial phase is 0 °, and between adjacent, phase difference is 60/n degree.In the embodiment of high-pressure matrix frequency converter of the present invention, n is natural number 3.Three-phase high-voltage alternating current by phase shift isolating transformer with 3 multiple array export, for matrixing cell array is powered.

2) matrixing cell array

With reference to Fig. 8, the array structure that matrixing cell array lines up 3 row × n capable by 3n matrixing power cell is formed, and in the embodiment of high-pressure matrix frequency converter of the present invention, n is natural number 3.It is capable corresponding that phase shift isolating transformer secondary winding is respectively organized respectively with array, and 3 secondary winding often in group are connected with 3 matrixing power cell one_to_one corresponding in every row respectively.In matrixing cell array, the power take-off of each column matrix transform power unit is connected successively, form a phase frequency, alternating voltage that amplitude is all adjustable exports, obtain the ability of superposition output voltage simultaneously, three row of matrixing power cell export and adopt Y connection to form three-phase alternating voltage output, and each converter unit is connected with master controller respectively by signal optical fibre.

3) matrixing power cell

With reference to Fig. 9, matrixing power cell adopts Z source-matrixing power cell, is respectively equipped with input filter and sub-controller.Wherein:

Input filter is made up of three filter resistances R1, R2, R3 and three filter capacitors C3, C4, C5, three filter resistance R1, R2, R3 one end are connected with the input of matrixing power cell respectively, the other end of resistance R1, R2, R3 is corresponding with one end of three filter capacitors C3, C4, C5 respectively connects, and the other end of three filter capacitors C3, C4, C5 is interconnected.

The prime rectifier of Z source-matrixing power cell is 3H bridge construction, comprise 3 brachium pontis, input three-phase alternating voltage, export two-way direct voltage, rear class inverter is 2H bridge construction, comprises 2 brachium pontis, input two-way direct voltage, output single-phase alternating voltage, is connected with Z source network between prime rectifier and rear class inverter.

Z source network is the X-type Z source network be made up of the first inductance L 1, second inductance L 2, first electric capacity C1 and the second electric capacity C2, as the first input end of Z source network after one end of first electric capacity C1 is connected with one end of the first inductance L 1, as the first output of Z source network after the other end of this first inductance L 1 is connected with one end of the second electric capacity C2, as the second input of Z source network after the other end of this second electric capacity C2 is connected with one end of the second inductance L 2, as the second output of Z source network after the other end of this second inductance L 2 is connected with the other end of the first electric capacity C1.The first input end of Z source network is connected with the output of the second input with rectification stage circuit, and the first output of Z source network is connected with the input of the second output with inverse cascade circuit.Based on the voltage transmission of the matrix converter in Z source than being the sensitizing factor of Z source network for 0.866B (B>=1), B, wherein t ₀for the straight-through zero-voltage state time, T _sit is a switch periods.

Sub-controller power line is connected with any two-phase in the input of the prime three-phase bridge rectifier circuit in array of power switches or three-phase; sub-controller holding wire is connected with rear class inverter with prime rectifier simultaneously; be responsible for the power device switching rule controlling each unit, realize the functions such as detection, protection, driving.

Master controller and each sub-controller, by Fiber connection, are responsible for the operation conditions of each sub-controller of cooperation control, and with reference to Figure 15, the step that master controller performs direct torque control comprises:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β}.

In the embodiment of asynchronous motor direct torque control device of the present invention, specifically comprise and adopt instrument transformer to measure asynchronous motor stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _c, utilize formula (1) and formula (2) to stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _ccarry out 3/2 conversion:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e.

In the embodiment of asynchronous motor direct torque control device of the present invention, specifically comprise and detect stator measuring resistance R _s, utilize formula (3) and formula (4) by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain the stator magnetic linkage ψ of motor _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cNwith the stator voltage vector of correspondence

In the embodiment of asynchronous motor direct torque control device of the present invention, specifically comprise and first utilize formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$

Selecting properly space vector of voltage, can form hexagon stator magnetic linkage or loop circle flux.Due to the restriction of the switching loss of high-pressure matrix frequency converter, its switching frequency can not be too high, therefore selects space vector of voltage to form six-arm dipmeter here.

Namely space vector of voltage selecting properly comprises the selection of space vector of voltage order, also comprises the selection that space vector of voltage provides the moment.

With reference to Figure 12 and Figure 13, to hexagon rotary flux linkage vector, set up and threephase stator voltage (A phase, B phase and C phase) perpendicular β coordinate system, stator magnetic linkage rotating space vector projects on β coordinate system, obtains the ψ of the one-period as Suo Shi (a) in Figure 14 under β coordinate system _{β A}, ψ _{β B}and ψ _{β C}waveform, ± ψ _sgfor flux linkage set value.By ψ _{β A}, ψ _{β B}and ψ _{β C}with ± ψ _sgrelatively, magnetic linkage switching signal is obtained for A phase magnetic linkage, by ψ _{β A}with ± ψ _sgcompare, work as ψ _{β A}be greater than ψ _sgtime, export as low level; Work as ψ _{β A}be less than-ψ _sgtime, for exporting as high level.B phase magnetic linkage and C phase magnetic linkage and ± ψ _sgmode is relatively similar with the mode in A phase, compares gained magnetic linkage switching signal as shown in (b) in Figure 14.The magnetic linkage switch represented by formula group (6) with voltage switching signal can be obtained respectively with its switching sequence figure is as shown in (c) in Figure 14.

$\begin{array}{c}\stackrel{\‾}{{\mathrm{S\ψ}}_A}=\stackrel{\‾}{S_{CN},}\\ \stackrel{\‾}{{\mathrm{S\ψ}}_B}=\stackrel{\‾}{S_{AN}}\\ \stackrel{\‾}{{\mathrm{S\ψ}}_C}=\stackrel{\‾}{S_{BN}}\end{array}---\left(6\right)$

Will with anti-phase, voltage control signal S can be obtained _aN, S _bN, S _cN, as shown in (d) in Figure 14.

Step 4 controls and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

In Study on direct torque control technology, its control mechanism is by constantly switching stator voltage space vector to adjust with the rotary speed controlling stator magnetic linkage.In the embodiment of asynchronous motor direct torque control device of the present invention, specifically comprise and first determine voltage switch vector table.For A phase, matrixing power cell each in Fig. 8 is launched, after expansion as shown in figure 11.B phase and C phase demodulation figure and A similar, just switch reference numerals is different, launches no longer one by one here.

For the class high voltage converter adopting high-pressure matrix inverter supply, if adopt direct torque control to be obviously inappropriate, because single power cell inverse cascade can only form 2 space vectors to the inverse cascade of each high-voltage matrix converter power cell.The power cell of the A phase be cascaded into, B phase, C phase considers by the present invention.For A phase, because the control action of power cell each in A phase is identical, therefore the inverter of A phase three power cells synthesizes 2 space vector of voltage, as in Figure 11, as the switching voltage status signal S in power cell A1-A3 _{7, A1}, S _{10, A1}, S _{7, A2}, S _{10, A2}, S _{7, A3}, S _{10, A3}synthesize a space vector time closed, high voltage " 1 " can be represented; S _{8, A1}, S _{9, A1}, S _{8, A2}, S _{9, A2}, S _{8, A3}, S _{9, A3}synthesize another space vector time closed, low-voltage " 0 " can be represented.In like manner, B phase and C phase also synthesize 2 space vector of voltage respectively.A phase,

B phase, C are mutually combined, can form 8 space vector of voltage that Direct Torque needs, as shown in table 1.

Table 1 voltage switch vector table

In table: U _dA=V _{d, A1}+ V _{d, A2}+ V _{d, A3}; U _dB=V _{d, B1}+ V _{d, B2}+ V _{d, B3}; U _dC=V _{d, C1}+ V _{d, C2}+ V _{d, C3}.

U under three phase mains symmetric case _dA=U _dB=U _dC=U _d, inverter 8 three dimensional vector diagrams as shown in figure 12, corresponding stator voltage vector u _sas shown in table 1.S in each space vector of voltage and step 3 _aN, S _bN, S _cNon off state is corresponding, as shown in (e) He table 1 in Figure 14.

After determining voltage switch vector table, according to S _aN, S _bN, S _cNand voltage vector option table 1 breaker in middle state, the switch motion of control inverter, thus the stator voltage changing motor, because stator voltage affects the stator magnetic linkage of motor and then the angle theta changed between stator magnetic linkage and rotor flux linkage vector, reach the object controlling motor torque, the final rotating speed controlling motor.

The present invention gives the embodiment of asynchronous motor direct torque control method, the method for direct torque control is described as follows:

The principle of direct torque control

According to manufacturing technique requirent, the rotating speed of control and adjustment motor is final purpose.But rotating speed is controlled by the torque of motor.And the Formula of Electromagnetic of motor is

In formula, K _mproportionality coefficient, with be stator magnetic linkage vector rotor flux linkage vector respectively, θ is with between angle.From above formula, the magnetic linkage of motor and the runnability of motor closely related, the essence of direct torque control is the rotary speed of the stator magnetic linkage by controlling motor, realizes changing with angle theta between vector, reaches the object controlling motor torque, thus controls rotating speed.

And the pass between stator magnetic linkage and stator voltage is when motor stable operation is in higher rotation speed, ignore stator pressure drop R _si _simpact, then visible, stator magnetic linkage can be controlled by controlling stator voltage.

The method of direct torque control

As shown in figure 15, the control method of asynchronous motor direct torque control device of the present invention, comprises the following steps:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β}.

In the embodiment of asynchronous motor direct torque control method of the present invention, specifically comprise and adopt instrument transformer to measure asynchronous motor stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _c, utilize formula (1) and formula (2) to stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _ccarry out 3/2 conversion, obtain the current value i under the α β coordinate system of equivalence _{s α}, i _{s β}with magnitude of voltage u _{s α}, u _{s β}:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e.

In the embodiment of asynchronous motor direct torque control method of the present invention, specifically comprise and detect stator measuring resistance R _s, by the stator current value i obtained _{s α}, i _{s β}with magnitude of voltage u _{s α}, u _{s β}, utilize formula (3) and formula (4) by rotating vector and obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cNwith the stator voltage vector of correspondence

In the embodiment of asynchronous motor direct torque control method of the present invention, specifically comprise and first utilize formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion, obtain the projection ψ at β coordinate system _{β A}, ψ _{β B}, ψ _{β C}:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$

Step 4 controls and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

With reference to Figure 12 and Figure 13, to hexagon rotary flux linkage vector, set up and A phase, B phase and the perpendicular β coordinate system of C phase threephase stator voltage, stator magnetic linkage rotating space vector projects on β coordinate system, obtains the ψ of the one-period as Suo Shi (a) in Figure 14 under β coordinate system _{β A}, ψ _{β B}and ψ _{β C}waveform, ± ψ _sgfor flux linkage set value.By ψ _{β A}, ψ _{β B}and ψ _{β C}with ± ψ _sgrelatively, magnetic linkage switching signal is obtained with for A phase magnetic linkage, by ψ _{β A}with ± ψ _sgcompare, work as ψ _{β A}be greater than ψ _sgtime, export as low level; Work as ψ _{β A}be less than-ψ _sgtime, for exporting as high level.B phase magnetic linkage and C phase magnetic linkage and ± ψ _sgmode is relatively similar with the mode in A phase, compares gained magnetic linkage switching signal as shown in (b) in Figure 14.The magnetic linkage switch represented by formula group (6) with voltage switching signal can be obtained respectively with its switching sequence figure is as shown in (c) in Figure 14.

Will with anti-phase, voltage switching signal S can be obtained _aN, S _bN, S _cN, as shown in (d) in Figure 14.

Step 4 controls and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

The power cell of the A phase be cascaded into, B phase, C phase considers by the present invention.For A phase, because the control action of power cell each in A phase is identical, therefore the inverter of three power cells synthesizes 2 space vector of voltage, as in Figure 10, as the switching voltage status signal S in power cell A1-A3 _{7, A1}, S _{10, A1}, S _{7, A2}, S _{10, A2}, S _{7, A3}, S _{10, A3}synthesize a space vector time closed, high voltage " 1 " can be represented; S _{8, A1}, S _{9, A1}, S _{8, A2}, S _{9, A2}, S _{8, A3}, S _{9, A3}synthesize another space vector time closed, low-voltage " 0 " can be represented.In like manner, B phase and C phase also synthesize 2 space vector of voltage respectively.A phase, B phase, C are mutually combined, can form 8 space vector of voltage that Direct Torque needs, as shown in table 1.

U under three phase mains symmetric case _dA=U _dB=U _dC=U _d, inverter 8 three dimensional vector diagrams as shown in figure 12, corresponding stator voltage vector as shown in table 1.S in each space vector of voltage and step 3 _aN, S _bN, S _cNon off state is corresponding, as shown in (e) in Figure 14 and table 1.

After determining voltage switch vector table, according to S _aN, S _bN, S _cNand voltage vector option table 1 breaker in middle state, the switch motion of control inverter, thus the stator voltage changing motor, because stator voltage affects the stator magnetic linkage of motor and then the angle theta changed between stator magnetic linkage and rotor flux linkage vector, reach the object controlling motor torque, the final rotating speed controlling motor.

Embodiment recited above is only be described the preferred embodiment of the present invention; not the spirit and scope of the present invention are limited; do not departing under design prerequisite of the present invention; the various modification that in this area, common engineers and technicians make technical scheme of the present invention and improvement; protection scope of the present invention all should be fallen into; the technology contents of request protection of the present invention, all records in detail in the claims.

Claims (9)

1. an asynchronous motor direct torque control device, comprises asynchronous motor, it is characterized in that: also comprise high-pressure matrix frequency converter, and described high-pressure matrix frequency converter comprises phase shift isolating transformer, matrixing cell array and master controller, wherein:

Described phase shift isolating transformer has 3n three-phase secondary winding, and n is natural number, and every 3 secondary winding are one group and have identical phase place, and secondary winding is respectively organized phase place and increased progressively successively, and initial phase is 0 °, and between adjacent, phase difference is 60/n degree; Three-phase high-voltage alternating current by described phase shift isolating transformer with 3 multiple array export, for described matrixing cell array is powered;

Described matrixing cell array comprises 3n matrixing power cell, line up 3 row × n capable, it is capable corresponding that described phase shift isolating transformer secondary winding is respectively organized respectively with array, 3 secondary winding often in group respectively with often row in 3 described matrixing power cell one_to_one corresponding be connected, in described matrixing cell array, each power take-off arranging described matrixing power cell is connected successively, and three row of described matrixing power cell export and adopt Y connection to form three-phase alternating voltage output;

Described matrixing power cell is Z source-matrixing power cell, wherein prime rectifier is 3H bridge construction, comprise 3 brachium pontis, input three-phase alternating voltage, export two-way direct voltage, rear class inverter is 2H bridge construction, comprise 2 brachium pontis, input two-way direct voltage, output single-phase alternating voltage, is connected with Z source network between prime rectifier and rear class inverter, described Z source network is by the first inductance L 1, second inductance L 2, the X-type Z source network that first electric capacity C1 and the second electric capacity C2 forms, as the first input end of Z source network after one end of described first electric capacity C1 is connected with one end of described first inductance L 1, as the first output of Z source network after the other end of described first inductance L 1 is connected with one end of described second electric capacity C2, as the second input of Z source network after the other end of described second electric capacity C2 is connected with one end of described second inductance L 2, as the second output of Z source network after the other end of described second inductance L 2 is connected with the other end of described first electric capacity C1, the first input end of described Z source network is connected with the output of the second input with rectification stage circuit, first output of Z source network is connected with the input of the second output with inverse cascade circuit,

Described each matrixing power cell is connected with a sub-controller respectively, and described master controller is connected with each described matrixing unit and each sub-controller respectively by signal optical fibre, and the step that described master controller performs direct torque control comprises:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β};

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e;

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cN, according to S _aN, S _bN, S _cNthe switch motion controlling converter inverse cascade obtains corresponding stator voltage vector

Step 4 is by controlling and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

2. asynchronous motor direct torque control device according to claim 1, it is characterized in that: wherein said matrixing power cell also comprises input filter, described input filter is by three filter resistance R1, R2, R3 and three filter capacitor C3, C4, C5 is formed, three described filter resistance R1, R2, R3 one end is connected with the input of matrixing power cell respectively, three described filter resistance R1, R2, the other end described filter capacitor C3 with three respectively of R3, C4, one end correspondence series connection of C5, three described filter capacitor C3, C4, the other end of C5 is interconnected.

3. asynchronous motor direct torque control device according to claim 2, is characterized in that: in wherein said step 1, utilizes formula (1) and formula (2) to stator current i _a, i _b, i _cwith stator voltage u _a, u _b, u _ccarry out 3/2 conversion:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

4. asynchronous motor direct torque control device according to claim 3, is characterized in that: in wherein said step 2, utilizes formula (3) and formula (4) by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain the stator magnetic linkage ψ of motor _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

5. asynchronous motor direct torque control device according to claim 4, is characterized in that: in wherein said step 3, utilizes formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$

6., according to the control method of the arbitrary described asynchronous motor direct torque control device of claim 1-5, it is characterized in that: the method comprises the following steps:

Step 1 detects motor stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _cand carry out 3/2 conversion, obtain the rotating vector u under two-phase rest frame _{s α}, u _{s β}and i _{s α}, i _{s β};

Step 2 is by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain stator magnetic linkage ψ _{s α}, ψ _{s β}with electromagnetic torque T _e;

Step 3 couple stator magnetic linkage ψ _{s α}, ψ _{s β}adopt 2/3 conversion, obtain the ψ that to project on β coordinate system _{β A}, ψ _{β B}, ψ _{β C}, obtain magnetic linkage switching signal through Schmidt trigger and by magnetic linkage switching signal determine voltage switching signal and then obtain S _aN, S _bN, S _cN, according to S _aN, S _bN, S _cNthe switch motion controlling converter inverse cascade obtains corresponding stator voltage vector

Step 4 is by controlling and S _aN, S _bN, S _cNcorresponding stator voltage, makes the angle theta between stator voltage change stator magnetic linkage and rotor flux linkage vector, thus controls motor torque, the final rotating speed controlling motor.

7. control method according to claim 6, is characterized in that: in wherein said step 1, utilizes formula (1) and formula (2) to stator voltage u _a, u _b, u _cwith stator current i _a, i _b, i _ccarry out 3/2 conversion:

$\left[\begin{array}{c}{i}_{s\mathrm{\α}}\\ i_{s\mathrm{\β}}\\ 0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]---\left(1\right)$

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

8. control method according to claim 7, is characterized in that: in wherein said step 2, utilizes formula (3) and formula (4) by rotating vector u _{s α}, u _{s β}and i _{s α}, i _{s β}obtain the stator magnetic linkage ψ of motor _{s α}, ψ _{s β}with electromagnetic torque T _e:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{s\mathrm{\α}}}{dt}=-R_s{i}_{s\mathrm{\α}}+u_{s\mathrm{\α}}\\ \frac{{\mathrm{d\ψ}}_{s\mathrm{\β}}}{dt}=-R_s{i}_{s\mathrm{\β}}+u_{s\mathrm{\β}}\end{array}\right.---\left(3\right)$

T _e＝n _p(i _sβψ _sα-i _sαψ _sβ)(4)

Wherein, n _pfor number of pole-pairs.

9. control method according to claim 8, is characterized in that: in wherein said step 3, utilizes formula (5) to stator magnetic linkage ψ _{s α}, ψ _{s β}carry out 2/3 conversion:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\β}A}\\ {\mathrm{\ψ}}_{\mathrm{\β}B}\\ {\mathrm{\ψ}}_{\mathrm{\β}C}\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{s\mathrm{\α}}\\ {\mathrm{\ψ}}_{s\mathrm{\β}}\end{array}\right]---\left(5\right).$