CN105827173A - Waveform modulation method and device of single-phase induction motor - Google Patents

Abstract

The invention discloses a waveform modulation method and device of a single-phase induction motor. The method includes the steps of: locking the on-off state of a certain phase in a three-phase bridge winding circuit to obtain a modulating wave of a secondary winding voltage phase angle in each interval; calculating a critical phase angle when local distortion of a waveform of the modulating wave occurs; and calculating a W phase modulation duty ratio D<W> of the modulating wave again according to the critical phase angle. Implementation of the waveform modulation method has the beneficial effects that by the method of locking the on-off state of a certain phase, the utilization rate of DC bus voltage is improved; and through calculation of D<W> again when distortion of the waveform occurs, i.e., in a waveform recessed interval, the waveform in the vicinity of a wave crest is properly lowered and a recess of another phase is filled, and the voltage waveform is guaranteed to have no jump point, thereby reducing the harmonic distortion rate.

Description

A kind of waveform modulated method and device of single phase induction motor

Technical field

The present invention relates to electrical equipment drive technology field, particularly relate to the waveform modulated method and device of a kind of single phase induction motor.

Background technology

Monocyclic-start induction motor because of simple in construction, need not supporting three-phase electrical source of power, the feature such as easy to use, be used widely in the products such as household electrical appliance with system.In order to realize the target of energy-saving and emission-reduction, in the urgent need to these also being implemented energy-saving and frequency-variable control.Additionally, at new energy field, the application market of photovoltaic water-raising system constantly expands in recent years, variable frequency regulating speed control realize especially MPPT maximum power point tracking control necessary means, and the water pump of below nominal power 2.2kW use monocyclic-start induction motor occupy sizable ratio.But, conventional frequency control is mainly for three phase alternating current motor, and the VFC for monocyclic-start induction motor still lacks further investigation and matured product.

The service requirement stator winding of induction conductivity can provide rotating excitation field, and three phase induction motor passes through stator winding and the input power of three-phase symmetrical, produces preferable rotating excitation field.And the stator of monocyclic-start induction motor generally main winding and auxiliary winding by orthogonal is constituted, if simply just applying single-phase alternating current, can only produce alternation standing wave magnetic field, motor cannot normally start and run.At present, most common method is by auxiliary capacitor of connecting in auxiliary winding so that the phase contrast of master/slave winding current is pi/2 (Fig. 1 a), thus forms rotating excitation field.Therefore, for the variable frequency regulating speed control of monocyclic-start induction motor, there is several alternative.

Scheme 1: do not change structure and the connection type of monocyclic-start induction motor, is provided the single-phase PWM frequency conversion voltage meeting V/f characteristic requirements, it is achieved variable frequency regulating speed control (Fig. 1 b), has circuit structure and the simple advantage of control method by single H bridge converter.But, due to the existence of auxiliary capacitor in auxiliary winding so that the frequency characteristic difference of master/slave winding circuit impedance is big, it is impossible to make both electric currents keep rational phase contrast in whole frequency range, thus affect frequency modulation operation characteristic.Test result indicate that a single-phase deep well submerged pump, even if being configured with optimal auxiliary capacitor, minimum initiation culture is 35Hz, and the minimum operation frequency after startup is 25Hz, it will have a strong impact on range of operation and the efficiency of system.It addition, PWM voltage can cause the increase of pulsating current in auxiliary capacitor, affect its service life.

Scheme 2: remove auxiliary capacitor, biphase inverter circuit (Fig. 1 c), the phase contrast equal in magnitude to main winding and auxiliary winding applying respectively using dual H-bridge is the alternating voltage of pi/2.Have and control the advantage simple, DC bus-bar voltage utilization rate is high.However, it is desirable to use 8 switching devices and implement to control to it, cost is high, poor universality.And one end of master/slave winding is linked togather by major part monocyclic-start induction motor in inside, as public input, site of deployment is difficult to thoroughly separate master/slave winding.

Scheme 3: utilize existing converter or inverter product, connects with auxiliary winding A, main winding M and the common port C of single-phase electric pump respectively by the outfan (U, V, W) of three-phase inverting circuit, and two windings are applied different voltage (Fig. 1 d).The advantage of its maximum is exactly without new hardware development, and versatility is good.But, the requirement to voltage waveform there occurs change, and due to the existence of common port, it is impossible to realize control completely self-contained to master/slave winding, need to change output waveform modulator approach.

Conventional three phase sine modulation method is the most simple and clear.On the basis of the voltage-phase of auxiliary winding, the delayed pi/2 of main winding voltage-phase, modulating wave is

$\left\{\begin{array}{c}{D}_U=0.5\&times;\&lsqb;1+msin(\mathrm{\&theta;}+\mathrm{\&pi;}/4)\&rsqb;\\ D_V=0.5\&times;\&lsqb;1+msin(\mathrm{\&theta;}+5\mathrm{\&pi;}/4)\&rsqb;\\ D_W=0.5\&times;\&lsqb;1+msin(\mathrm{\&theta;}+3\mathrm{\&pi;}/4)\&rsqb;\end{array}\right.---\left(1\right)$

Biphase sine voltage can be exported.

$\left\{\begin{array}{c}{U}_A=\frac{\sqrt{2}}{2}{\mathrm{mU}}_{dc}\sin \mathrm{\&theta;}\\ U_M=\frac{\sqrt{2}}{2}{\mathrm{mU}}_{dc}\sin (\mathrm{\&theta;}-\mathrm{\&pi;}/2)\end{array}\right.---\left(2\right)$

In formula (1) (2), D_U、D_V、D_W: each phase modulation duty cycle, scope is 0～1；U_M: main winding voltage, unit is V；U_A: auxiliary winding voltage, unit is V；U_dc: DC bus-bar voltage, unit is V；M: modulation rate, scope is 0～1；θ: auxiliary winding voltage phase angle, unit is rad.

Modulating wave and output voltage waveforms are as shown in Fig. 2 a and Fig. 2 b.As can be seen here, voltage waveform is good, but DC bus-bar voltage peak use rate (during m=1) is onlyVoltage request when high frequency runs cannot be met.

The modulating wave of formula (1) is changed into by sinusoidal overshoot method:

$\left\{\begin{array}{c}{D}_U=0.5\&times;\&lsqb;1+\sqrt{2}msin(\mathrm{\&theta;}+\mathrm{\&pi;}/4)\&rsqb;\\ D_V=0.5\&times;\&lsqb;1+\sqrt{2}msin(\mathrm{\&theta;}+5\mathrm{\&pi;}/4)\&rsqb;\\ D_W=0.5\&times;\&lsqb;1+\sqrt{2}msin(\mathrm{\&theta;}+3\mathrm{\&pi;}/4)\&rsqb;\end{array}\right.---\left(3\right)$

WhenTime, output voltage is sinusoidal wave.

$\left\{\begin{array}{c}{U}_A={\mathrm{mU}}_{dc}\sin \mathrm{\&theta;}\\ U_M={\mathrm{mU}}_{dc}\sin (\mathrm{\&theta;}-\mathrm{\&pi;}/2)\end{array}\right.---\left(4\right)$

WhenTime, owing to the adjustable extent of dutycycle is 0～1, D_U、D_VAnd D_WWill be by limit value.Therefore, the peak value of output voltage disclosure satisfy that requirement, but distortion occurs in waveform, and virtual value reduces, as shown in Fig. 3 a and Fig. 3 b.As m=1, output voltage waveforms is close to triangular wave, and percent harmonic distortion is 13.4%, and virtual value is 0.826 times of identical peak value sinusoidal voltage, i.e. by sinusoidal overshoot, can DC bus-bar voltage utilization rate be improved to 0.826 by 0.707.But during high-speed cruising, the problem such as low voltage, harmonic current increase will be faced.

Summary of the invention

It is an object of the invention to provide the waveform modulated method and device of a kind of single phase induction motor, solve the deficiency of various single phase induction motor variable frequency regulating speed control schemes in prior art.

Technical scheme is accomplished by

It is an object of the present invention to provide a kind of waveform modulated method of single phase induction motor, it is provided that three-phase bridge winding circuit, comprise the following steps:

The on off state locking a certain phase in described three-phase bridge winding circuit is in the modulating wave in each interval to obtain auxiliary winding voltage phase angle；

Calculate the critical phase parallactic angle during waveform generation local distortion of described modulating wave；

The W phase modulation duty cycle of described modulating wave is recalculated according to described critical phase parallactic angle.

In waveform modulated method of the present invention, the on off state of a certain phase in described locking described three-phase bridge winding circuit includes following sub-step obtaining the step of the modulating wave of auxiliary winding voltage phase angle in each interval:

Lock the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=mcos\mathrm{\&theta;}\end{array}& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array}\right.;$

Lock the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1\\ D_V=1-m(\sin \mathrm{\&theta;}+\cos \mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array}\right.;$

Lock the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+mcos\mathrm{\&theta;}\end{array}& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array}\right.;$

Lock the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=0\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array}\right.;$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

In waveform modulated method of the present invention, the step of the critical phase parallactic angle when waveform of the described modulating wave of described calculating occurs local distortion includes following sub-step:

When the waveform of described modulating wave occurs local distortion, obtain described modulation rate:

According to m (sin θ₀+cosθ₀The described critical phase parallactic angle of)=1 calculating:

${\mathrm{\&theta;}}_0=arcsin\frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4};$

Wherein, θ₀For critical phase parallactic angle.

In waveform modulated method of the present invention, the step of the described W phase modulation duty cycle recalculating described modulating wave according to described critical phase parallactic angle includes:

Work as θ₀＜ θ ＜ 2-θ₀Time calculate W phase modulation duty cycle:

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0);$

As π+θ₀＜ θ ＜ 3 pi/2-θ₀Time calculate W phase modulation duty cycle:

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0).$

On the other hand, it is provided that the waveform modulated device of a kind of single phase induction motor, including:

Modulating wave acquisition module, is in the modulating wave in each interval for locking the on off state of a certain phase in described three-phase bridge winding circuit to obtain auxiliary winding voltage phase angle；

Critical phase parallactic angle computing module, for calculating the critical phase parallactic angle when waveform of described modulating wave occurs local distortion；

Dutycycle roll back module, for recalculating the W phase modulation duty cycle of described modulating wave according to described critical phase parallactic angle.

In waveform modulated device of the present invention, described modulating wave acquisition module includes:

First interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=mcos\mathrm{\&theta;}\end{array}& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array}\right.;$

Second interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1\\ D_V=1-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array}\right.;$

3rd interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+mcos\mathrm{\&theta;}\end{array}& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array}\right.;$

4th interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=0\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array}\right.;$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

In waveform modulated device of the present invention, described critical phase parallactic angle computing module includes:

Modulation rate obtains submodule, for when the waveform of described modulating wave occurs local distortion, obtains described modulation rate:

Critical phase parallactic angle calculating sub module, for according to m (sin θ₀+cosθ₀The described critical phase parallactic angle of)=1 calculating:

${\mathrm{\&theta;}}_0=arcsin\frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4};$

Wherein, θ₀For critical phase parallactic angle.

In waveform modulated device of the present invention, described dutycycle roll back module includes:

Rerun submodule in first interval, for working as θ₀＜ θ ＜ 2-θ₀Time calculate W phase modulation duty cycle:

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0);$

Rerun submodule in second interval, for as π+θ₀＜ θ ＜ 3 pi/2-θ₀Time calculate W phase modulation duty cycle:

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0).$

Therefore, the invention has the beneficial effects as follows, by the method locking a certain phase on off state, improve DC bus-bar voltage utilization rate；And by when distortion occurs in waveform, i.e. recalculate D in waveform depression interval_W, suitably force down waveform near crest, fill up the depression of another phase, and ensure that voltage waveform does not has jump, thus reduce percent harmonic distortion.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:

Fig. 1 a is the structural representation of the auxiliary winding of single phase induction motor；

Fig. 1 b is the structural representation of the H bridge winding of single phase induction motor；

Fig. 1 c is the structural representation of the dual H-bridge winding of single phase induction motor；

Fig. 1 d is the structural representation of the three-phase bridge winding of single phase induction motor；

Phase angle and the Sine Modulated waveform schematic diagram of dutycycle when Fig. 2 a is m=0.9；

Phase angle and the Sine Modulated waveform schematic diagram of output voltage when Fig. 2 b is m=0.9；

Phase angle and the sinusoidal overshoot waveform diagram of dutycycle when Fig. 3 a is m=0.9；

Phase angle and the sinusoidal overshoot waveform diagram of output voltage when Fig. 3 b is m=0.9；

The waveform modulated method flow diagram of a kind of single phase induction motor that Fig. 4 provides for the present invention；

During the m=0.5 that Fig. 5 a provides for the present invention, phase angle clamps modulation waveform schematic diagram with the bus of dutycycle；

During the m=0.5 that Fig. 5 b provides for the present invention, phase angle clamps modulation waveform schematic diagram with the bus of output voltage；

During the m=0.9 that Fig. 5 c provides for the present invention, phase angle clamps modulation waveform schematic diagram with the bus of dutycycle；

During the m=0.9 that Fig. 5 d provides for the present invention, phase angle clamps modulation waveform schematic diagram with the bus of output voltage；

Fig. 6 a is the 30Hz current waveform figure of sinusoidal overshoot method；

Fig. 6 b is the 50Hz current waveform figure of sinusoidal overshoot method；

Fig. 6 c is the 30Hz current waveform figure of bus clamp method；

Fig. 6 d is the 50Hz current waveform figure of bus clamp method.

Detailed description of the invention

In order to the technical characteristic of the present invention, purpose and effect are more clearly understood from detail, below comparison accompanying drawing is described the detailed description of the invention of the present invention.Should be appreciated that being specifically described of the following description only embodiment of the present invention, should not limit the scope of the invention with this.

The present invention provides the waveform modulated method and device of a kind of single phase induction motor, it is intended that improve DC bus-bar voltage utilization rate further, it is provided that a kind of bus clamp modulation method.By the method locking a certain phase on off state, improve DC bus-bar voltage utilization rate；And by when distortion occurs in waveform, i.e. recalculate D in waveform depression interval_W, suitably force down waveform near crest, fill up the depression of another phase, and ensure that voltage waveform does not has jump, thus reduce percent harmonic distortion.

Seeing the waveform modulated method flow diagram of a kind of single phase induction motor that Fig. 4, Fig. 4 provide for the present invention, this waveform modulated method (i.e. bus clamp modulation method) comprises the following steps S1-S3:

S1, the on off state of a certain phase locked in described three-phase bridge winding circuit are in the modulating wave in each interval to obtain auxiliary winding voltage phase angle；This step is by locking the on off state of a certain phase, it is ensured that the output of positive negative peak voltage, and modulating wave calculating formula is as follows:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=m\cos \mathrm{\&theta;}\end{array}& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array}\right.---\left(5\right)$

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1\\ D_V=1-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array}\right.---\left(6\right)$

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+m\cos \mathrm{\&theta;}\end{array}& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array}\right.---\left(7\right)$

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=0\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array}\right.---\left(8\right)$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

S2, calculate described modulating wave waveform occur local distortion time critical phase parallactic angle；Seeing Fig. 5 a-5d, Fig. 5 a-5d is the modulating wave under different modulating rate different modulating rate and output voltage waveforms, whenTime, every section of phase-locked a length of pi/2, it is possible to output is the most sinusoidal wave；WhenTime, every section of phase-locked length is gradually increased, and local distortion occurs in waveform, and has jump；As m=1, every section of phase-locked length increases to 3 π/4, and crest voltage meets the requirements, and dc bus utilization rate reaches 0.957, but voltage waveform distortion is obvious, and percent harmonic distortion is 15.6%.To this, a kind of method proposing improvement, waveform depression interval recalculate D_W, suitably force down waveform near crest, fill up the depression of another phase, and ensure that voltage waveform does not has jump.

WhenTime, by m (sin θ₀+cosθ₀)=1, can obtain

${\mathrm{\&theta;}}_0=arcsin\frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4}---\left(9\right)$

S3, recalculate the W phase modulation duty cycle of described modulating wave according to described critical phase parallactic angle.Need to recalculate D_WInterval and computing formula as follows:

Interval 1: θ₀＜ θ ＜ pi/2-θ₀

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0)---\left(10\right)$

Interval 2: π+θ₀＜ θ ＜ 3 pi/2-θ₀

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0)---\left(11\right)$

Therefore formula (5)～formula (11) constitute the core of the present invention.Fig. 5 a-5d is the modulating wave under different modulating rate and output voltage waveforms, main winding voltage occurs distorting with the partial section in negative half period uphill process, auxiliary winding voltage partial section during positive half cycle rises and negative half period declines in the decline of positive half cycle, the sinusoidal wave form that rest interval holding is good.As m=1, every half cycle voltage waveform is made up of triangular wave and sine wave.Compared with bus clamper method, DC bus-bar voltage utilization rate reduces to 0.913, but percent harmonic distortion significantly reduces to 8.7%.

Additionally, the present invention also provides for the waveform modulated device of a kind of single phase induction motor, this device can be completed by computer software, and this device includes:

Modulating wave acquisition module, is in the modulating wave in each interval for locking the on off state of a certain phase in described three-phase bridge winding circuit to obtain auxiliary winding voltage phase angle；

Critical phase parallactic angle computing module, for calculating the critical phase parallactic angle when waveform of described modulating wave occurs local distortion；

Dutycycle roll back module, for recalculating the W phase modulation duty cycle of described modulating wave according to described critical phase parallactic angle.

Preferably, described modulating wave acquisition module includes:

First interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=mcos\mathrm{\&theta;}\end{array}& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array}\right.;$

Second interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1\\ D_V=1-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array}\right.;$

3rd interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+mcos\mathrm{\&theta;}\end{array}& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array}\right.;$

4th interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\left\{\begin{array}{cc}\begin{array}{c}{D}_U=0\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array}\right.;$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

Preferably, described critical phase parallactic angle computing module includes:

Modulation rate obtains submodule, for when the waveform of described modulating wave occurs local distortion, obtains described modulation rate:

Critical phase parallactic angle calculating sub module, for according to m (sin θ₀+cosθ₀The described critical phase parallactic angle of)=1 calculating:

${\mathrm{\&theta;}}_0=arcsin\frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4};$

Wherein, θ₀For critical phase parallactic angle.

Preferably, described dutycycle roll back module includes:

Rerun submodule in first interval, for working as θ₀＜ θ ＜ 2-θ₀Time calculate W phase modulation duty cycle:

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0);$

Rerun submodule in second interval, for as π+θ₀＜ θ ＜ 3 pi/2-θ₀Time calculate W phase modulation duty cycle:

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0).$

The method and device of the present invention is applicable to three phase converter or the inverter of routine, can be easily achieved by corresponding software program.

The present invention also provides for a specific embodiment: the system of embodiment constitutes identical with Fig. 1 d, and load is a nominal power 750W, lift 56m, flow 2m³The single-phase deep well submerged pump of/h.In order to compare and verify the effect of control mode of the present invention, clamp method with sinusoidal overshoot method and bus respectively and water pump is implemented variable frequency regulating speed control (5～50Hz), system all energy stable operation, experimental result is as shown in table 1, and wherein phase contrast refers to the phase contrast of main winding current and auxiliary winding electric current.Fig. 6 a-6d is portion current waveforms.During less than 40Hz, current waveform is good, and the phase contrast of master/slave winding current is stable about pi/2；During higher than 40Hz, voltage waveform distortion causes current waveform to distort, and current and phase difference changes the most therewith；Affected by DC bus-bar voltage utilization rate, during 50Hz the output voltage of sine overshoot method be 169V, water pump input power be 1287W, and bus clamp method output voltage be 196V, water pump input power be 1405W, and current waveform be improved significantly.

The experimental result of 1 two kinds of modulator approaches of table

There is provided herein the various operations of embodiment.In one embodiment, described one or more operations may be constructed the computer-readable instruction of storage on one or more computer-readable medium, and it will make calculating equipment perform described operation when being performed by electronic equipment.Describing the order of some or all of operation, to should not be construed as to imply that these operations the most order dependent.It will be appreciated by those skilled in the art that the alternative sequence of the benefit with this specification.Furthermore, it is to be understood that not all operation must exist in each embodiment provided in this article.

And, word used herein " preferably " means serving as example, example or illustration.Feng Wen is described as " preferably " any aspect or design is not necessarily to be construed as more favourable than other aspects or design.On the contrary, the use of word " preferably " is intended to propose in a concrete fashion concept."or" that as used in this application term "or" is intended to mean to comprise and non-excluded "or".I.e., unless otherwise or the clearest, " X uses A or B " means that nature includes any one of arrangement.That is, if X uses A；X uses B；Or X uses A and B both, then " X uses A or B " is met in aforementioned any example.

And, although illustrate and describing the disclosure relative to one or more implementations, but those skilled in the art will appreciate that equivalent variations and amendment based on to reading and the understanding of the specification and drawings.The disclosure includes all such amendments and modification, and is limited only by the scope of the following claims.Particularly with the various functions performed by said modules (such as element, resource etc.), the random component (unless otherwise instructed) of the appointment function (such as it is functionally of equal value) corresponding to performing described assembly it is intended to, even if structurally the open structure with the function in the exemplary implementations performing the disclosure shown in this article is not equal to for describing the term of such assembly.Although additionally, the special characteristic of the disclosure is disclosed relative to the only one in some implementations, but this feature can combine with other features one or more that can be such as expectation and other favourable implementations for given or application-specific.And, term " is included ", " having ", " containing " or its deformation be used in detailed description of the invention or claim for, such term be intended to by " comprise " to term similar in the way of include.

Each functional unit in the embodiment of the present invention can be integrated in a processing module, it is also possible to is that unit is individually physically present, it is also possible to two or more unit are integrated in a module.Above-mentioned integrated module both can realize to use the form of hardware, it would however also be possible to employ the form of software function module realizes.If described integrated module is using the form realization of software function module and as independent production marketing or use, it is also possible to be stored in a computer read/write memory medium.Storage medium mentioned above can be read only memory, disk or CD etc..Above-mentioned each device or system, can perform the method in correlation method embodiment.

In sum; although the present invention is disclosed above with preferred embodiment; but above preferred embodiment also is not used to limit the present invention; those of ordinary skill in the art; without departing from the spirit and scope of the present invention; all can make various change and retouching, therefore protection scope of the present invention defines in the range of standard with claim.

Claims (8)

1. the waveform modulated method of a single phase induction motor, it is provided that three-phase bridge winding circuit, it is characterised in that comprise the following steps:

The on off state locking a certain phase in described three-phase bridge winding circuit is in the modulating wave in each interval to obtain auxiliary winding voltage phase angle；

Calculate the critical phase parallactic angle during waveform generation local distortion of described modulating wave；

The W phase modulation duty cycle of described modulating wave is recalculated according to described critical phase parallactic angle.

Waveform modulated method the most according to claim 1, it is characterised in that the on off state of a certain phase in described locking described three-phase bridge winding circuit includes following sub-step obtaining the step of the modulating wave of auxiliary winding voltage phase angle in each interval:

Lock the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=mcos\mathrm{\&theta;}\end{array}\right.& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array};$

Lock the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=1\\ D_V=1-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}\right.& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array};$

Lock the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+mcos\mathrm{\&theta;}\end{array}\right.& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array};$

Lock the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=0\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}\right.& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array};$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

Waveform modulated method the most according to claim 2, it is characterised in that the step of the critical phase parallactic angle when waveform of the described modulating wave of described calculating occurs local distortion includes following sub-step:

When the waveform of described modulating wave occurs local distortion, obtain described modulation rate:

According to m (sin θ₀+cosθ₀The described critical phase parallactic angle of)=1 calculating:

${\mathrm{\&theta;}}_0=\arcsin \frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4};$

Wherein, θ₀For critical phase parallactic angle.

Waveform modulated method the most according to claim 3, it is characterised in that the step of the described W phase modulation duty cycle recalculating described modulating wave according to described critical phase parallactic angle includes:

Work as θ₀＜ θ ＜ 2-θ₀Time calculate W phase modulation duty cycle:

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0);$

As π+θ₀＜ θ ＜ 3 pi/2-θ₀Time calculate W phase modulation duty cycle:

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0).$

5. the waveform modulated device of a single phase induction motor, it is characterised in that including:

Modulating wave acquisition module, is in the modulating wave in each interval for locking the on off state of a certain phase in described three-phase bridge winding circuit to obtain auxiliary winding voltage phase angle；

Critical phase parallactic angle computing module, for calculating the critical phase parallactic angle when waveform of described modulating wave occurs local distortion；

Dutycycle roll back module, for recalculating the W phase modulation duty cycle of described modulating wave according to described critical phase parallactic angle.

Waveform modulated device the most according to claim 5, it is characterised in that described modulating wave acquisition module includes:

First interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=0\\ D_W=mcos\mathrm{\&theta;}\end{array}\right.& -\frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{\mathrm{\&pi;}}{4}\end{array};$

Second interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=1\\ D_V=1-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=1-m\sin \mathrm{\&theta;}\end{array}\right.& \frac{\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{3\mathrm{\&pi;}}{4}\end{array};$

3rd interval modulation submodule, for locking the on off state of the V phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=1+m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_V=1\\ D_W=1+mcos\mathrm{\&theta;}\end{array}\right.& \frac{3\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{5\mathrm{\&pi;}}{4}\end{array};$

4th interval modulation submodule, for locking the on off state of the U phase in described three-phase bridge winding circuit to obtainModulating wave in interval:

$\begin{array}{cc}\left\{\begin{array}{c}{D}_U=1\\ D_V=-m(sin\mathrm{\&theta;}+cos\mathrm{\&theta;})\\ D_W=-m\sin \mathrm{\&theta;}\end{array}\right.& \frac{5\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}<\frac{7\mathrm{\&pi;}}{4}\end{array};$

Wherein, θ is auxiliary winding voltage phase angle, D_UFor U phase modulation duty cycle, D_VFor V phase modulation duty cycle, D_WFor W phase modulation duty cycle, m is modulation rate.

Waveform modulated device the most according to claim 6, it is characterised in that described critical phase parallactic angle computing module includes:

Modulation rate obtains submodule, for when the waveform of described modulating wave occurs local distortion, obtains described modulation rate:

Critical phase parallactic angle calculating sub module, for according to m (sin θ₀+cosθ₀The described critical phase parallactic angle of)=1 calculating:

${\mathrm{\&theta;}}_0=\arcsin \frac{1}{\sqrt{2}m}-\frac{\mathrm{\&pi;}}{4};$

Wherein, θ₀For critical phase parallactic angle.

Waveform modulated device the most according to claim 7, it is characterised in that described dutycycle roll back module includes:

Rerun submodule in first interval, for working as θ₀＜ θ ＜ 2-θ₀Time calculate W phase modulation duty cycle:

$D_W={\mathrm{mcos\&theta;}}_0-\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-{\mathrm{\&theta;}}_0);$

Rerun submodule in second interval, for as π+θ₀＜ θ ＜ 3 pi/2-θ₀Time calculate W phase modulation duty cycle:

$D_W=1-{\mathrm{mcos\&theta;}}_0+\frac{{\mathrm{mcos\&theta;}}_0-0.5}{\mathrm{\&pi;}/4-{\mathrm{\&theta;}}_0}(\mathrm{\&theta;}-\mathrm{\&pi;}-{\mathrm{\&theta;}}_0).$