CN102684581A - Control method of driving duty ratio of permanent magnet motor - Google Patents

Abstract

The invention relates to a control method of the driving duty ratio of a permanent magnet motor and belongs to the technical field of motor driving. The method includes calculating voltage amplitude of a permanent magnet synchronous motor inverter direct current bus and different switch time sequences of a switch tube and further calculating voltage of the switch tube under different duty ratios. Simultaneously, the driving duty ratio of the permanent magnet motor is controlled according to characteristics of the permanent magnet synchronous motor and phase relation between the angle of the permanent magnet synchronous motor and three-phase stator current. The direction of the three-phase stator current is calculated under different magnetic pole angles of the permanent magnet synchronous motor, and voltage is compensated into phase voltage of a three-phase stator according to current direction of the motor. The control method reduces effects of a switch dead area on working performance of a loading system and limited errors of current detection accuracy, improves sine degree of current of the permanent magnet synchronous motor, reduces system noise and optimizes system operation effects.

Description

A kind of magneto drives the control method of duty ratio

Technical field

The present invention relates to the control method that a kind of magneto drives duty ratio, belong to the motor-driven technical field.

Background technology

The driver element of AC servo generally uses the three phase full bridge voltage source inverter.Because be used for two power switchs conducting complementally and shutoff always in the ideal case of a brachium pontis of pulse width modulation inverter.In fact the conducting of power tube and shutoff need the regular hour, and the turn-off time is longer than ON time, and its switching time is uncontrollable.If directly add complementary control signal, will inevitably cause the straight-through of dc bus, burn power component.Therefore, add certain time of delay for the drive signal of power component, when making the switching tube work of same brachium pontis, form one section dead band of closing simultaneously.Always close afterwards earlier with two switching tubes that guarantee same brachium pontis and to lead to, prevented the straight-through phenomenon of full-bridge inverter.

Summary of the invention

The objective of the invention is to propose the control method that a kind of magneto drives duty ratio; The follow-up switch dead-zone compensation method that position-based detects; Utilize the effect of the information raising controller switches dead area compensation of position detection unit; With the sinusoidal degree of effective raising permagnetic synchronous motor electric current, thereby reduce noise.

The magneto that the present invention proposes drives the control method of duty ratio, and two kinds of different schemes are arranged, and first kind of scheme may further comprise the steps:

The DC bus-bar voltage amplitude of (1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter

Then go up switching tube

Turn-off following switching tube

Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube

Body diode The conducting afterflow exists mid point a point voltage clamper

(2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

When the magnetic pole angle is 0<θ<π/3, in the threephase stator electric current, i _a>0, i _b<0, i _c>0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, C phase _Comp, compensate reverse voltage V mutually to B _Comp

When the magnetic pole angle is π/3<θ<2 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub>>0, i<sub >b</sub><0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of B, C phase<sub >Comp</sub>

When the magnetic pole angle is 2 π/3<θ<during π, in the threephase stator electric current, i _a>0, i _b>0, i _c<0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, B phase _Comp, compensation reverse voltage V in the phase voltage of C phase _Comp

When the magnetic pole angle is π<θ<4 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of B phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A, C phase<sub >Comp</sub>

When the magnetic pole angle is 4 π/3<θ<5 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub>>0, then B, C compensate forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A phase<sub >Comp</sub>

When the magnetic pole angle is 5 π/3<θ<during 2 π, in the threephase stator electric current, i _a<0, i _b<0, i _c>0, then C compensates forward voltage V mutually in the permagnetic synchronous motor threephase stator _Comp, compensation reverse voltage V in the phase voltage of A, B phase _Comp

The computing formula of above-mentioned bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, span is 0.6～0.7, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

Second kind of scheme may further comprise the steps:

The DC bus-bar voltage amplitude of (1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter

The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter

Then go up switching tube

Turn-off following switching tube Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube Body diode

The conducting afterflow exists mid point a point voltage clamper

(2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

In magnetic pole angle 0<θ<under the π state, work as i _a>0 o'clock, the A in the permagnetic synchronous motor threephase stator compensated forward voltage V mutually _CompWork as i _a<, compensate reverse voltage V mutually at 0 o'clock to A _Comp

In magnetic pole angle 2 π/3<θ<under 5 π/>3 states, work as i<sub >b</sub>>0 o'clock, B compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>Work as i<sub >b</sub><, compensate reverse voltage V mutually at 0 o'clock to B<sub >Comp</sub>

In magnetic pole angle-2 π/3<θ<under π/>3 states, work as i<sub >c</sub>>0 o'clock, C compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>Work as i<sub >c</sub><, compensate reverse voltage V mutually at 0 o'clock to C<sub >Comp</sub>

Wherein, the amplitude computing formula of bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, value is 0.65, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

The magneto that the present invention proposes drives the control method of duty ratio; Its advantage is: reduced the influence of the switch dead band of permagnetic synchronous motor controller to the load system service behaviour, reduced the restriction error of the current detection accuracy of traditional dead-zone compensation method existence simultaneously.This method can effectively improve the sinusoidal degree of permagnetic synchronous motor electric current, thereby reduces system noise, and effect optimizes the system operation.

Description of drawings

Fig. 1 is in the inventive method, the adding mode of Dead Time.

Fig. 2 is in the inventive method, has the sequential chart of the inverter pulse-width modulation of Dead Time.

Fig. 3 is the current waveform of existing no dead area compensation.

Fig. 4 is to use the current waveform of band dead area compensation after the inventive method.

Embodiment

The magneto that the present invention proposes drives the control method of duty ratio, and two kinds of different schemes are arranged, and first kind of scheme may further comprise the steps:

The DC bus-bar voltage amplitude of (1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter

The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter

Then go up switching tube Turn-off following switching tube

Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube

Body diode

The conducting afterflow exists mid point a point voltage clamper Shown in Figure 2 is the inverter pulse-width modulation sequential chart that has Dead Time.

(2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

When the magnetic pole angle is 0<θ<π/3, in the threephase stator electric current, i _a>0, i _b<0, i _c>0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, C phase _Comp, compensate reverse voltage V mutually to B _Comp

When the magnetic pole angle is π/3<θ<2 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub>>0, i<sub >b</sub><0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of B, C phase<sub >Comp</sub>

When the magnetic pole angle is 2 π/3<θ<during π, in the threephase stator electric current, i _a>0, i _b>0, i _c<0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, B phase _Comp, compensation reverse voltage V in the phase voltage of C phase _Comp

When the magnetic pole angle is π<θ<4 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of B phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A, C phase<sub >Comp</sub>

When the magnetic pole angle is 4 π/3<θ<5 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub>>0, then B, C compensate forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A phase<sub >Comp</sub>

When the magnetic pole angle is 5 π/3<θ<during 2 π, in the threephase stator electric current, i _a<0, i _b<0, i _c>0, then C compensates forward voltage V mutually in the permagnetic synchronous motor threephase stator _Comp, compensation reverse voltage V in the phase voltage of A, B phase _Comp

The computing formula of above-mentioned bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, span is 0.6～0.7, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

Second kind of scheme may further comprise the steps:

The DC bus-bar voltage amplitude of (1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter

The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter Then go up switching tube

Turn-off following switching tube

Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube

Body diode

The conducting afterflow exists mid point a point voltage clamper

The sequential chart that has the inverter pulse-width modulation of Dead Time.

(2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

In magnetic pole angle 0<θ<under the π state, work as i _a>0 o'clock, the A in the permagnetic synchronous motor threephase stator compensated forward voltage V mutually _CompWork as i _a<, compensate reverse voltage V mutually at 0 o'clock to A _Comp

In magnetic pole angle 2 π/3<θ<under 5 π/>3 states, work as i<sub >b</sub>>0 o'clock, B compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>Work as i<sub >b</sub><, compensate reverse voltage V mutually at 0 o'clock to B<sub >Comp</sub>

In magnetic pole angle-2 π/3<θ<under π/3 states, as ic>0 o'clock, C compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>Work as i<sub >c</sub><, compensate reverse voltage V mutually at 0 o'clock to C<sub >Comp</sub>

Wherein, the amplitude computing formula of bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, value is 0.65, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

In the said method, because the three-phase of inverter and permagnetic synchronous motor is symmetrical, the description of said method is that example is carried out with A mutually.

Below in conjunction with accompanying drawing, introduce the operation principle of the inventive method:

The adding mode of inverter Dead Time is as shown in Figure 1; Because the existence of delay time, the fundamental voltage output of voltage of inverter is lower than the output of expectation, shows non-linear; And because error voltage first-harmonic size is certain, so desired output voltage non-linear apparent in view when low.

The switch dead band causes the inverter output voltage waveform to distort, and causes output current wave to produce distortion, the i.e. intermodulation distortion of electric current.

1, Dead Time is long more, and the loss of inverter output fundamental voltage is big more, and the voltage waveform distortion degree is big more; Load fundamental current amplitude descends many more, and the current waveform distortion is also serious more.

2, for the Dead Time of confirming, when the power-factor of load diminishes, inverter output fundamental voltage amplitude is increased, voltage-form distortion rate diminishes, and the fundamental current amplitude reduces, and it is big that the current waveform aberration rate becomes.

3, when output voltage was low, the space voltage vector amplitude was very little, and the relative ON time of three road and bridge arms shortens, and it is big that the influence of Dead Time becomes.

4, the dead band not only influences output voltage amplitude, also influences its phase place; The dead band makes pulse-width modulation waveform no longer be symmetrical in the center, and therefore, the amplitude of space voltage vector produces deviation, and phase place also changes.

Fig. 3 is the current waveform of no dead area compensation, and as can be seen from the figure the phase current waveform of permagnetic synchronous motor has certain distortion, can bring the additional noise and the vibration of motor operation.Fig. 4 is the current waveform of band dead area compensation, can find out among the figure that through adopt compensation method of the present invention, the sinusoidal degree of current of electric obviously improves, and effectively reduces current distortion, reduces electromagnetic noise.

Claims (2)

1. a magneto drives the control method of duty ratio, it is characterized in that this method may further comprise the steps:

The DC bus-bar voltage amplitude of (1-1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter

The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter

Then go up switching tube

Turn-off following switching tube

Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube

Body diode

The conducting afterflow exists mid point a point voltage clamper

(1-2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

When the magnetic pole angle is 0<θ<π/3, in the threephase stator electric current, i _a>0, i _b<0, i _c>0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, C phase _Comp, compensate reverse voltage V mutually to B _Comp

When the magnetic pole angle is π/3<θ<2 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub>>0, i<sub >b</sub><0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of B, C phase<sub >Comp</sub>

When the magnetic pole angle is 2 π/3<θ<during π, in the threephase stator electric current, i _a>0, i _b>0, i _c<0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of A, B phase _Comp, compensation reverse voltage V in the phase voltage of C phase _Comp

When the magnetic pole angle is π<θ<4 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub><0, then in the permagnetic synchronous motor threephase stator, compensate forward voltage V in the phase voltage of B phase<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A, C phase<sub >Comp</sub>

When the magnetic pole angle is 4 π/3<θ<5 π/>3 o'clock, in the threephase stator electric current, i<sub >a</sub><0, i<sub >b</sub>>0, i<sub >c</sub>>0, then B, C compensate forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>, compensation reverse voltage V in the phase voltage of A phase<sub >Comp</sub>

When the magnetic pole angle is 5 π/3<θ<during 2 π, in the threephase stator electric current, i _a<0, i _b<0, i _c>0, then C compensates forward voltage V mutually in the permagnetic synchronous motor threephase stator _Comp, compensation reverse voltage V in the phase voltage of A, B phase _Comp

The computing formula of above-mentioned bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, span is 0.6～0.7, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

2. a magneto drives the control method of duty ratio, it is characterized in that this method may further comprise the steps:

The DC bus-bar voltage amplitude of (2-1) establishing the inverter that drives magneto is V _d, the direction that electric current flows out inverter is a forward, switching tube on electric current is flowed through inverter The time, the voltage of the mid point a of one group of upper and lower switching tube does in the inverter

Then go up switching tube

Turn-off following switching tube

Conducting; As the Dead Time T that is in switching tube, descends switching tube to turn-off simultaneously _D1The time, then descend switching tube Body diode The conducting afterflow exists mid point a point voltage clamper

(2-2) phase relation of the angle of the characteristic of permagnetic synchronous motor and permagnetic synchronous motor magnetic pole and threephase stator electric current drives duty ratio to magneto and controls as follows:

In magnetic pole angle 0<θ<under the π state, work as i _a>0 o'clock, the A in the permagnetic synchronous motor threephase stator compensated forward voltage V mutually _CompWork as i _a<, compensate reverse voltage V mutually at 0 o'clock to A _Comp

In magnetic pole angle 2 π/3<θ<under 5 π/>3 states, work as i<sub >b</sub>>0 o'clock, B compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Cpmp</sub>Work as i<sub >b</sub><, compensate reverse voltage V mutually at 0 o'clock to B<sub >Comp</sub>

In magnetic pole angle-2 π/3<θ<under π/>3 states, work as i<sub >c</sub>>0 o'clock, C compensated forward voltage V mutually in the permagnetic synchronous motor threephase stator<sub >Comp</sub>Work as i<sub >c</sub><, compensate reverse voltage V mutually at 0 o'clock to C<sub >Comp</sub>

Wherein, the amplitude computing formula of bucking voltage is:

$V_{\mathrm{comp}}=\mathrm{Factor}*V_d*\left(\frac{T_d}{T_{\mathrm{period}}}\right)$

T wherein _PeriodThe cycle of each compensation, i.e. the inverse of the switching frequency of permagnetic synchronous motor controller, Factor is the adjustment coefficient, value is 0.65, T _dBe Dead Time, span is 0.02～0.06 times of controller pwm switch cycle, V _dBe the inverter DC bus-bar voltage.

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