CN101969273B - Asymmetric inverter for single-phase induction motor - Google Patents

Abstract

The invention discloses an asymmetric inverter for a single-phase induction motor, belongs to the field of power electronic technology, and solves the problem that the speed of a single-phase induction motor fluctuates because an inverted power supply is adopted by the single-phase induction motor. The asymmetric inverter comprises two direct current power supplies, a switch tube Sm and a three-phase full-bridge inverter circuit, wherein an output end of the two direct current power supplies which are connected in series is connected with an input end of the three-phase full-bridge inverter circuit, while the other output end is connected with the other input end of the three-phase full-bridge inverter circuit; the switch tube Sm is connected between the two output ends of the first direct current power supply DC1 in parallel for controlling switching state of the switch tube; the number N1 of turns of a main coil is not equal to the number N2 of turns of an auxiliary coil; the coil with greater number of turns of the single-phase induction motor is connected between the output ends of a first bridge arm and a third bridge arm in parallel; and the coil with smaller number of turns of the single-phase induction motor is connected between the output ends of a second bridge arm and the third bridge arm in parallel.

Description

The asymmetric inverter that is used for single phase induction motor

Technical field

The present invention relates to be used for the asymmetric inverter of single phase induction motor, belong to electric and electronic technical field.

Background technology

Single phase induction motor be one type of application time the earliest, the single phase induction motor of the power supply of the widest, the single phase poaer supply of range of application and low-power applications.It is carried out the speed governing transformation, or in the motor of new production the good control system of configuration performance, have the significance that improves runnability and energy savings.Its two groups of stator coil (main coil L _QWith ancillary coil L _D) place with the mode of quadrature usually, the stator power that is added to two coils should have the phase difference of 90 degree, to guarantee that forming the stator rotating magnetic field makes rotor rotation.Fig. 1 is the model sketch map of single-phase asynchronous motor, and wherein two stator winding are used L respectively _QAnd L _DExpression.The rotor winding is represented with α and β.ω is a rotor velocity.The axis of α phase winding and D phase winding L _DThe angle theta angle of axis be the space displacement variable.

Produce two coil orthogonal control voltage method and have two kinds: first method is ancillary coil L _DConnect some electric component again with main coil L _QParallel connection only needs a stator control voltage, therefore can use single phase alternating current power supply; Second method is the stator control voltage that two coils add quadrature respectively, and this just controls respectively in the two-phase alternating current source.

In the prior art, single phase induction motor is carried out two distinguish control mode mutually, its control circuit is referring to shown in Figure 2.

Because the continuous development of Power Electronic Technique and microprocessor technology, be the technology maturation of polyphase ac electric energy from the single phase alternating current power supply commutation inversion, for the two-phase of single phase induction motor respectively control technology technical foundation is provided.And load motor two mutually respectively control technology can save capacitor, be convenient to speed governing, the easy to use and similar control technology of three phase alternating current motor, therefore be widely used in the control of single phase induction motor.

The monophase machine service conditions:

Single phase induction motor has following fundamental relation

$\left\{\begin{array}{c}{\stackrel{\·}{U}}_Q=-{\stackrel{\·}{E}}_Q+j{X}_{\mathrm{Q\σ}}\\ {\stackrel{\·}{U}}_D=-{\stackrel{\·}{E}}_D+j{X}_{\mathrm{D\σ}}\end{array}\right.---\left(1\right)$

Wherein

Be the additional power source voltage of main coil,

Be the induced electromotive force of main coil, X _{Q σ}Be the leakage reactance of main coil,

Be the additional power source voltage of ancillary coil, Be the induced electromotive force of ancillary coil, X _{D σ}It is the leakage reactance of ancillary coil.

The general leakage reactance of thinking two phase windings approx than equal turn ratio square, promptly

X _Qσ/X _Dσ≈(N _Q/N _D) ²(2)

When the monophase machine symmetrical operation, should have

${\stackrel{\·}{E}}_Q/{\stackrel{\·}{E}}_D=j{(N_Q/N_D)}^2---\left(3\right)$

Like this, the voltage conditions when just obtaining symmetrical operation,

${\stackrel{\·}{U}}_D/{\stackrel{\·}{U}}_D=j(N_Q/N_D)---\left(4\right)$

Promptly two voltages that coil bore should be directly proportional with two corresponding numbers of turn of coil.

In the inverter shown in Figure 2, alternating current is transformed into direct current behind the AC-DC modular converter, promptly is equivalent to DC power supply, this DC power supply through voltage stabilizing, be two winding L that AC signal is added to single phase induction motor respectively through the bridge inverter main circuit inversion again _QAnd L _DOn, because the symmetry of power supply circuits, the amplitude of added alternating voltage is the same on two windings.But; Two windings of single phase induction motor all are asymmetric; Just unequal, this will make the stator of single phase induction motor rotate magnetomotive track is not circular, but oval-shaped; Speed during consequently single phase induction motor turns around when operation is unequal, has velocity perturbation during single phase induction motor operation just.

Summary of the invention

The present invention seeks to cause motor to have the problem of velocity perturbation, a kind of asymmetric inverter that is used for single phase induction motor is provided for the inverter that solves the single phase induction motor employing.

The present invention is used for first kind of scheme of the asymmetric inverter of single phase induction motor:

The asymmetric inverter that is used for single phase induction motor comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit; Another output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected another input of three phase full bridge inverter circuit; Switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1; Be used to control the on off state of the first DC power supply DC1; The main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis; The ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N greater than ancillary coil ₂

The present invention is used for second kind of scheme of the asymmetric inverter of single phase induction motor:

The asymmetric inverter that is used for single phase induction motor comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit; Another output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected another input of three phase full bridge inverter circuit; Switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1; Be used to control the on off state of the first DC power supply DC1; The ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis; The main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N less than ancillary coil ₂

Advantage of the present invention: inverter provided by the invention adds the voltage of different amplitudes according to the number of turn situation of the major-minor coil of single phase induction motor, and the voltage magnitude that promptly is added on the motor windings is directly proportional with the number of turn of winding, bears voltage magnitude and changes the conducting state of first DC power supply of adjusting task according to switching tube in the three phase full bridge; According to satisfactory logical relation; By its switch of switching tube Sm control, like this, the voltage that is loaded on the major-minor coil is along with operating state is clocklike changing; Be not unalterable; Make single phase induction motor to operate steadily, reduce the fluctuation of speed, obtain better operational effect.

Description of drawings

Fig. 1 is a single phase induction motor winding construction sketch map in the background technology;

Fig. 2 is the inverter structure sketch map that single phase induction motor adopted in the background technology;

Fig. 3 is the inverter structure sketch map of single phase induction motor of the present invention;

Fig. 4 is the structural representation of execution mode two;

Fig. 5 is the logic relation picture of each switch.

Embodiment

Embodiment one: this execution mode is described below in conjunction with Fig. 3 and Fig. 5; This execution mode is used for the asymmetric inverter of single phase induction motor; It comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit; Another output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected another input of three phase full bridge inverter circuit; Switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1, is used to control the on off state of the first DC power supply DC1, and the main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis; The ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N greater than ancillary coil ₂Be N ₁＞N ₂

The three phase full bridge inverter circuit is made up of six switching tubes, and six switching tubes are respectively the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅With the 6th switching tube S ₆, the upper and lower position of first brachium pontis is provided with the first switching tube S respectively ₁With second switch pipe S ₂, the upper and lower position of second brachium pontis is provided with the 3rd switching tube S respectively ₃With the 4th switching tube S ₄, the upper and lower position of the 3rd brachium pontis is provided with the 5th switching tube S respectively ₅With the 6th switching tube S ₆, the logical relation between the on off state of the on off state of switching tube Sm and six switching tubes is:

In the formula, the switching tube value is 1 this switching tube conducting of expression, and the switching tube value is that 0 this switching tube of expression turn-offs.We have only utilized two phases wherein the alternating voltage of the three phase full bridge inverter circuit output of this execution mode, and one is carried in the main coil two ends mutually, and another is carried on the ancillary coil mutually.

The first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅, the 6th switching tube S ₆Adopt the switch mosfet pipe that carries the IGBT switching tube of body diode or carry body diode with switching tube Sm.

The body diode that each switching tube carries is the reverse parallel connection setting, and when switching tube adopted the IGBT switching tube, the anode of body diode was connected with the emitter of IGBT switching tube, and the negative electrode of body diode is connected with the collector electrode of IGBT switching tube; When switching tube adopted N type switch mosfet pipe, the anode of body diode was connected with the source electrode of switch mosfet pipe, and the negative electrode of body diode is connected with the drain electrode of switch mosfet pipe; When switching tube adopted P type switch mosfet pipe, the anode of body diode was connected with the drain electrode of switch mosfet pipe, and the negative electrode of body diode is connected with the source electrode of switch mosfet pipe.

The rated voltage value of ac voltage

and that should equal main coil after the inversion of ac voltage after the inversion of DC1

and DC2, promptly

For two voltages that coil bore should be directly proportional with two corresponding numbers of turn of coil, should satisfy following relation

$({\tilde{U}}_1+{\tilde{U}}_2)/{\tilde{U}}_2={\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_1/N_2---\left(6\right)$

Therefore obtain

${\tilde{U}}_1=({\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_1/N_2-1){\&times;\tilde{U}}_2---\left(7\right)$

For satisfying formula (5), fet switch turn-offed when inverter was supplied power to main coil, and fet switch conducting when ancillary coil is supplied power.So the condition of work of SM is: when S1 conducting, S4 conducting and S6 conducting simultaneously, when perhaps S2 conducting, S3 conducting, S5 conducting simultaneously, it is in off state.Can be written as following relation:

$S_m=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_1\&CenterDot;{\mathrm{<figure-callout\; id="4"\; label="S"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_4{\&CenterDot;\mathrm{<figure-callout\; id="6"\; label="S"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_6+{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_3{\&CenterDot;\mathrm{<figure-callout\; id="5"\; label="S"\; filenames="HDA0000029014750000012.png,HDA0000029014750000021.png"\; state="\{\{state\}\}">S</figure-callout>}}_5}---\left(8\right)$

Fig. 5 provides a digital circuit figure suc as formula (8) said logical relation.

Under these conditions, it is as shown in table 1 to be added to the virtual voltage of main coil and ancillary coil:

Table 1

Every kind of state of table 1 is only mentioned the switching tube of three conductings, and NM other three switching tube default conditions are for turn-offing.V _ACRepresent the voltage between first brachium pontis and the 3rd brachium pontis, V _BCRepresent the voltage between second brachium pontis and the 3rd brachium pontis; V _DC1Represent the first DC power supply DC1 voltage, V _DC2Represent the second DC power supply DC2 voltage.

Provide a concrete embodiment below, the rated voltage of single phase induction motor is 220V, and it is the FET of IRF840 that switch adopts model, and its parameter is 8.0A, 500V.The ratio parameter of the major-minor coil of this motor stator is:

K=N ₁/ N ₂=1.1, the number of turn N of the main coil of the single phase induction motor of this motor ₁Number of turn N greater than ancillary coil ₂Be N ₁＞N ₂

Thereby have

${\tilde{U}}_2={\tilde{U}}_1/(1.1-1)$

Therefore, obtain:

By the

and value can be obtained across the first DC power supply DC1 and the second DC voltage value of the voltage across the power supply DC2.

Embodiment two: this execution mode is described below in conjunction with Fig. 4 and Fig. 5; This execution mode is used for the asymmetric inverter of single phase induction motor; It is characterized in that; It comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit, and the first DC power supply DC1 is connected another input of three phase full bridge inverter circuit with another output after the second DC power supply DC2 connects, and switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1; Be used to control the on off state of the first DC power supply DC1; The ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis, and the main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N less than ancillary coil ₂Be N ₁＜N ₂

The three phase full bridge inverter circuit is made up of six switching tubes, and six switching tubes are respectively the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅With the 6th switching tube S ₆, the upper and lower position of first brachium pontis is provided with the first switching tube S respectively ₁With second switch pipe S ₂, the upper and lower position of second brachium pontis is provided with the 3rd switching tube S respectively ₃With the 4th switching tube S ₄, the upper and lower position of the 3rd brachium pontis is provided with the 5th switching tube S respectively ₅With the 6th switching tube S ₆, the logical relation between the on off state of the on off state of switching tube Sm and six switching tubes is:

In the formula, the switching tube value is 1 this switching tube conducting of expression, and the switching tube value is that 0 this switching tube of expression turn-offs.

The first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅, the 6th switching tube S ₆Adopt the switch mosfet pipe that carries the IGBT switching tube of body diode or carry body diode with switching tube Sm.

Principle of this execution mode and execution mode one are basic identical, and unique difference is N ₁＜N ₂, the location swap that main coil and ancillary coil are provided with gets final product, and in like manner obtains:

${\tilde{U}}_2=({\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000029014750000021.png,HDA0000029014750000022.png"\; state="\{\{state\}\}">N</figure-callout>}}_2/N_1-1)\&times;{\tilde{U}}_1.$

Other is all identical with execution mode one, repeats no more here.

Claims (4)

1. the asymmetric inverter that is used for single phase induction motor; It is characterized in that; It comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit; Another output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected another input of three phase full bridge inverter circuit; Switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1, is used to control the on off state of the first DC power supply DC1, and the main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis; The ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N greater than ancillary coil ₂, the first DC power supply DC1 voltage is greater than the second DC power supply DC2 voltage,

The three phase full bridge inverter circuit is made up of six switching tubes, and six switching tubes are respectively the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅With the 6th switching tube S ₆, the upper and lower position of first brachium pontis is provided with the first switching tube S respectively ₁With second switch pipe S ₂, the upper and lower position of second brachium pontis is provided with the 3rd switching tube S respectively ₃With the 4th switching tube S ₄, the upper and lower position of the 3rd brachium pontis is provided with the 5th switching tube S respectively ₅With the 6th switching tube S ₆, the logical relation between the on off state of the on off state of switching tube Sm and six switching tubes is: $S_m=\stackrel{\&OverBar;}{S_1\&CenterDot;S_4\&CenterDot;S_6+S_2\&CenterDot;S_3\&CenterDot;S_5}.$

2. the asymmetric inverter that is used for single phase induction motor according to claim 1 is characterized in that, the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅, the 6th switching tube S ₆Adopt the switch mosfet pipe that carries the IGBT switching tube of body diode or carry body diode with switching tube Sm.

3. the asymmetric inverter that is used for single phase induction motor; It is characterized in that; It comprises the first DC power supply DC1, the second DC power supply DC2, switching tube Sm and three phase full bridge inverter circuit; An output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected an input of three phase full bridge inverter circuit; Another output after the first DC power supply DC1 and the second DC power supply DC2 series connection is connected another input of three phase full bridge inverter circuit; Switching tube Sm is connected in parallel on two outputs of the first DC power supply DC1, is used to control the on off state of the first DC power supply DC1, and the ancillary coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of first brachium pontis; The main coil of single phase induction motor is connected in parallel between the output of output and the 3rd brachium pontis of second brachium pontis, the number of turn N of the main coil of single phase induction motor ₁Number of turn N less than ancillary coil ₂, the first DC power supply DC1 voltage is greater than the second DC power supply DC2 voltage,

The three phase full bridge inverter circuit is made up of six switching tubes, and six switching tubes are respectively the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅With the 6th switching tube S ₆, the upper and lower position of first brachium pontis is provided with the first switching tube S respectively ₁With second switch pipe S ₂, the upper and lower position of second brachium pontis is provided with the 3rd switching tube S respectively ₃With the 4th switching tube S ₄, the upper and lower position of the 3rd brachium pontis is provided with the 5th switching tube S respectively ₅With the 6th switching tube S ₆, the logical relation between the on off state of the on off state of switching tube Sm and six switching tubes is: $S_m=\stackrel{\&OverBar;}{S_1\&CenterDot;S_4\&CenterDot;S_6+S_2\&CenterDot;S_3\&CenterDot;S_5}.$

4. the asymmetric inverter that is used for single phase induction motor according to claim 3 is characterized in that, the first switching tube S ₁, second switch pipe S ₂, the 3rd switching tube S ₃, the 4th switching tube S ₄, the 5th switching tube S ₅, the 6th switching tube S ₆Adopt the switch mosfet pipe that carries the IGBT switching tube of body diode or carry body diode with switching tube Sm.

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