CN103023393A - Control method of single-inverter bi-motor system - Google Patents

Abstract

The invention discloses a control method of a single-inverter bi-motor system. The method includes: firstly, obtaining a three-phase duty ratio of each three-phase motor according to a traditional SVPWM (space vector pulse width modulation) method; secondly, considering from the perspective of line voltage, tracking to obtain a minimum five-phase bridge arm duty ratio meeting system control requirements; and finally, obtaining a final five-phase bridge arm duty ratio according to an equipartition zero vector principle. The control method is capable of achieving automatic distribution of direct-current bus voltage between the two motors according to needs and bi-motor independent control in the real sense, avoids large storage space occupancy, and can be realized in a three-phase PWM (pulse width modulation) module of a standard DSP (digital signal processor).

Description

A kind of control method of single inverter dual motors system

Technical field

The invention belongs to motor-driven and control technology field, relate to a kind of control method of single inverter bi-motor.

Background technology

Because the extensive use in the industries such as weaving, papermaking, steel rolling and track traffic, multi-motors drive system and control method thereof are the study hotspots that scholars pay close attention to always.Usually in the multi-motors drive system of studying, every three phase electric machine is independently controlled by a three-phase inverter, is referred to as single inverter list electric system, and this also is control structure the most frequently used in the multi-motors drive system.Meanwhile, along with the development of polyphase machine, polyphase inverter is widely applied.So, in order to reduce the usage quantity of switching device, the novel multi-motors drive system control structure based on polyphase inverter has been proposed, namely adopt Five-phase inverter to control simultaneously two three phase electric machines, be referred to as the single inverter dual motors system.Compare with traditional two cover single inverter list electric systems, the salient feature of single inverter dual motors system has been saved two device for power switching exactly.In order to control the single inverter dual motors system, existing scholar has proposed a lot of control methods, such as equisection method, manage in advance, look-up table etc.

The DC bus-bar voltage of equisection method---single inverter dual motors system is given two motors by strict the grade.This method is actually and becomes DC bus-bar voltage to be original half two groups of separate single inverter list electric systems single inverter dual motors system equivalence, and namely the DC bus-bar voltage utilance of every motor only is 50%.

Manage in advance---this method brings up to 86.6% by the method for two electric machine operating characteristics of strict regulations in advance with the DC bus-bar voltage utilance of single inverter dual motors system, but meanwhile lost the independence on two Electric Machine Control.

Look-up table---this method is based on line voltage thought and proposes.For the single inverter dual motors system, phase voltage reflection be separate unit motor, local information of voltage, the reflection of line voltage then be the information of voltage of inverter, two motors, the overall situation.So, based on the look-up table of line voltage can realize DC bus-bar voltage between two motors automatically distribute as required and truly bi-motor is independently controlled.But look-up table need to take a large amount of memory spaces, and is difficult to realize in the three-phase PWM module of standardized digital signal process chip DSP.

Summary of the invention

The problem to be solved in the present invention is: the control method of existing single inverter dual motors system, exist the DC bus-bar voltage utilance of motor not high, or control independence is not enough, or occupying system resources is large, the problem that is difficult to realize in practice.

Technical scheme of the present invention is: a kind of control method of single inverter dual motors system, and adopt Five-phase inverter to control simultaneously two three phase electric machines, described control method comprises the steps:

1) obtains two three phase electric machines three-phase duty cycle, delta separately according to three-phase SVPWM _A1, δ _B1, δ _C1And δ _A2, δ _B2, δ _C2

2) defined parameters line modulation ratio obtains the line modulation ratio of Five-phase inverter brachium pontis according to formula (1):

$\left\{\begin{array}{c}{m}_{\mathrm{AC}}={\mathrm{\δ}}_{A1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{BC}}={\mathrm{\δ}}_{B1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{DC}}={\mathrm{\δ}}_{B2}-{\mathrm{\δ}}_{C2}\\ m_{\mathrm{EC}}={\mathrm{\δ}}_{A2}-{\mathrm{\δ}}_{C2}\end{array}\right.---\left(1\right)$

Wherein, subscript A, B, C, D, E represent five brachium pontis of Five-phase inverter, m _AC, m _BC, m _DC, m _ECBe respectively the line modulation ratio between brachium pontis A-C, brachium pontis B-C, brachium pontis D-C, brachium pontis E-C;

3) by formula (2) obtain respectively the maximum m in wired modulation ratio _MaxWith minimum value m _Min:

$\left\{\begin{array}{c}{m}_{\max }=\max \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\\ m_{\min }=\min \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\end{array}\right.---\left(2\right)$

4) the line voltage reference value of single inverter dual motors system is set saturation coefficient λ, wired voltage reference value equal proportion of single inverter dual motors system is reduced, final so that the maximum line voltage reference value is DC bus-bar voltage just:

$\mathrm{\λ}=\frac{1}{\max \{1,m_{\max }-m_{\min }\}}---\left(3\right)$

5) calculate the duty ratio of brachium pontis C according to the saturation coefficient of step 4), obtain the maximum δ in all duty ratios of brachium pontis C according to formula (4) _{C_max}With minimum value δ _{C_min}:

$\left\{\begin{array}{c}{\mathrm{\δ}}_{C\_\max }=\min \{1-\mathrm{\λ}{m}_{\max },1\}\\ {\mathrm{\δ}}_{C\_\min }=\max \{-\mathrm{\λ}{m}_{\min },0\}\end{array}\right.---\left(4\right)$

6) divide the zero vector principle of action time according to waiting, determined the final duty cycle, delta of brachium pontis C by formula (5) _C:

${\mathrm{\δ}}_C=\frac{{\mathrm{\δ}}_{C\_\max }+{\mathrm{\δ}}_{C\_\min }}{2}---\left(5\right)$

7) obtain again the duty ratio of each brachium pontis according to formula (6):

$\left\{\begin{array}{c}{\mathrm{\δ}}_A=\mathrm{\λ}{m}_{\mathrm{AC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_B=\mathrm{\λ}{m}_{\mathrm{BC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_D=\mathrm{\λ}{m}_{\mathrm{DC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_E=\mathrm{\λ}{m}_{\mathrm{EC}}+{\mathrm{\δ}}_C\end{array}\right.---\left(6\right)$

In the formula, δ _A, δ _B, δ _C, δ _D, δ _EBe respectively the duty ratio of brachium pontis A, B, C, D, E, according to the duty ratio of five brachium pontis determining, control when realizing Five-phase inverter to two three phase electric machines.

Beneficial effect: the inventive method is applicable to all Five-phase inverter double three-phase machine systems, simple general-purpose.Specific to technical scheme of the present invention, have following advantage:

1. be used in conjunction with traditional three-phase SVPWM method, the inventive method is simple;

2. compare with equisection method, the inventive method is not restricted to 50% with the voltage utilization of separate unit motor, but automatically distributes according to the voltage requirements of every motor;

With manage in advance the ratio, the inventive method does not need strictly to retrain in advance the operation characteristic of two three phase electric machines, the operation characteristic of two motors can not produce any influencing each other among the present invention in undersaturated situation, can truly realize the independent control of two motors;

4. compare with look-up table, the inventive method does not need to take a large amount of memory spaces, and easily realizes in the three-phase PWM module of standardized digital signal process chip DSP.

Description of drawings

Fig. 1 is the FB(flow block) of the inventive method;

Fig. 2 is the hardware experiment structural representation of the embodiment of the invention;

Fig. 3 is the experimental waveform of two permanent magnet synchronous motors rotating speed in the embodiment of the invention;

Fig. 4 is the duty ratio experimental waveform of permagnetic synchronous motor 1 in the embodiment of the invention;

Fig. 5 is the duty ratio experimental waveform of permagnetic synchronous motor 2 in the embodiment of the invention;

Fig. 6 is the duty ratio experimental waveform of Five-phase inverter in the embodiment of the invention.

Embodiment

The present invention at first obtains the three-phase duty ratio of every three phase electric machine according to traditional space vector pulse width modulation SVPWM (Space Vector Pulse Width Modulation) method; Then, consider from the line level angle, follow the tracks of five phase brachium pontis duty ratios of the minimum that is met system's control requirement; At last, obtain five final phase brachium pontis duty ratios according to the principle that waits minute zero vector.

The present invention will be described below with reference to accompanying drawings.

The control method of single inverter dual motors system of the present invention as shown in Figure 1, comprises the steps:

1) obtains two three phase electric machines three-phase duty cycle, delta separately according to traditional three-phase SVPWM _A1, δ _B1, δ _C1And δ _A2, δ _B2, δ _C2

2) this parameter of lead-in modulation ratio obtains the line modulation ratio of Five-phase inverter brachium pontis according to formula (1):

$\left\{\begin{array}{c}{m}_{\mathrm{AC}}={\mathrm{\δ}}_{A1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{BC}}={\mathrm{\δ}}_{B1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{DC}}={\mathrm{\δ}}_{B2}-{\mathrm{\δ}}_{C2}\\ m_{\mathrm{EC}}={\mathrm{\δ}}_{A2}-{\mathrm{\δ}}_{C2}\end{array}\right.---\left(1\right)$

Wherein, subscript A, B, C, D, E represent five brachium pontis of Five-phase inverter, m _AC, m _BC, m _DC, m _ECBe respectively the line modulation ratio between brachium pontis A-C, brachium pontis B-C, brachium pontis D-C, brachium pontis E-C;

3) by formula (2) obtain respectively the maximum m in wired modulation ratio _MaxWith minimum value m _Min:

$\left\{\begin{array}{c}{m}_{\max }=\max \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\\ m_{\min }=\min \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\end{array}\right.---\left(2\right)$

4) the line voltage reference value of single inverter dual motors system is set saturation coefficient λ, along with the operation of single inverter dual motors system, wired voltage reference value reduces according to saturation coefficient λ equal proportion:

$\mathrm{\λ}=\frac{1}{\max \{1,m_{\max }-m_{\min }\}}---\left(3\right)$

Maximum line voltage reference value after final so that equal proportion reduces is DC bus-bar voltage just;

5) consider from the line level angle, calculated the duty ratio of brachium pontis C by the saturation coefficient of step 4), follow the tracks of being met the brachium pontis duty ratio that system's control requires,

Obtain the maximum δ in all duty ratios of brachium pontis C according to formula (4) _{C_max}With minimum value δ _{C_min}:

$\left\{\begin{array}{c}{\mathrm{\δ}}_{C\_\max }=\min \{1-\mathrm{\λ}{m}_{\max },1\}\\ {\mathrm{\δ}}_{C\_\min }=\max \{-\mathrm{\λ}{m}_{\min },0\}\end{array}\right.---\left(4\right)$

6) divide the zero vector principle of action time according to waiting, finally determined the δ of brachium pontis C by formula (5) _C:

${\mathrm{\δ}}_C=\frac{{\mathrm{\δ}}_{C\_\max }+{\mathrm{\δ}}_{C\_\min }}{2}---\left(5\right)$

7) obtain again the duty ratio of each brachium pontis according to formula (6):

$\left\{\begin{array}{c}{\mathrm{\δ}}_A=\mathrm{\λ}{m}_{\mathrm{AC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_B=\mathrm{\λ}{m}_{\mathrm{BC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_D=\mathrm{\λ}{m}_{\mathrm{DC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_E=\mathrm{\λ}{m}_{\mathrm{EC}}+{\mathrm{\δ}}_C\end{array}\right.---\left(6\right)$

In the formula, δ _A, δ _B, δ _C, δ _D, δ _EBe respectively the duty ratio of brachium pontis A, B, C, D, E, according to the duty ratio of five brachium pontis determining, control when realizing Five-phase inverter to two three phase electric machines.Electric Machine Control according to duty ratio is as well known to those skilled in the art, no longer describes in detail.

The system hardware structure of embodiments of the invention comprises as shown in Figure 2: direct voltage source, Five-phase inverter, two three-phase permanent magnet synchronous motors.Wherein, two permanent magnet synchronous motors all adopts the i based on SVPWM _d=0 control method, direct voltage source voltage u _Dc=400V, switching frequency 2kHz.Fig. 3 is the experimental waveform of two permanent magnet synchronous motors rotating speed.Fig. 4 is the duty ratio experimental waveform of permagnetic synchronous motor 1.Fig. 5 is the duty ratio experimental waveform of permagnetic synchronous motor 2.Fig. 6 is the duty ratio experimental waveform according to the Five-phase inverter of the inventive method control.By shown in oscillogram as seen, the inventive method can effectively independently be controlled two motors.

This concept of lead-in modulation ratio of the present invention, consider to obtain the brachium pontis duty ratio of Five-phase inverter from the line level angle, do not limit the DC bus-bar voltage utilance of motor, can effectively independently control two motors, and as seen do not need to take a large amount of memory spaces by computational process yet.

The above only is better embodiment of the present invention; protection scope of the present invention is not limited with above-mentioned execution mode; as long as the equivalence that those of ordinary skills do according to disclosed content is modified or changed, all should include in the protection range of putting down in writing in claims.

Claims (1)

1. the control method of a single inverter dual motors system adopts Five-phase inverter to control simultaneously two three phase electric machines, it is characterized in that described control method comprises the steps:

1) obtains two three phase electric machines three-phase duty cycle, delta separately by three-phase SVPWM _A1, δ _B1, δ _C1And δ _A2, δ _B2, δ _C2

2) defined parameters line modulation ratio obtains the line modulation ratio of Five-phase inverter brachium pontis according to formula (1):

$\left\{\begin{array}{c}{m}_{\mathrm{AC}}={\mathrm{\δ}}_{A1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{BC}}={\mathrm{\δ}}_{B1}-{\mathrm{\δ}}_{C1}\\ m_{\mathrm{DC}}={\mathrm{\δ}}_{B2}-{\mathrm{\δ}}_{C2}\\ m_{\mathrm{EC}}={\mathrm{\δ}}_{A2}-{\mathrm{\δ}}_{C2}\end{array}\right.---\left(1\right)$

Wherein, subscript A, B, C, D, E represent five brachium pontis of Five-phase inverter, m _AC, m _BC, m _DC, m _ECBe respectively the line modulation ratio between brachium pontis A-C, brachium pontis B-C, brachium pontis D-C, brachium pontis E-C;

3) by formula (2) obtain respectively the maximum m in wired modulation ratio _MaxWith minimum value m _Min:

$\left\{\begin{array}{c}{m}_{\max }=\max \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\\ m_{\min }=\min \{m_{\mathrm{AC}},m_{\mathrm{BC}},m_{\mathrm{DC}},m_{\mathrm{EC}}\}\end{array}\right.---\left(2\right)$

4) the line voltage reference value of single inverter dual motors system is set saturation coefficient λ, wired voltage reference value equal proportion of single inverter dual motors system is reduced, final so that the maximum line voltage reference value is DC bus-bar voltage just:

$\mathrm{\λ}=\frac{1}{\max \{1,m_{\max }-m_{\min }\}}---\left(3\right)$

5) calculate the duty ratio of brachium pontis C according to the saturation coefficient of step 4), obtain the maximum δ in all duty ratios of brachium pontis C according to formula (4) _{C_max}With minimum value δ _{C_min}:

$\left\{\begin{array}{c}{\mathrm{\δ}}_{C\_\max }=\min \{1-\mathrm{\λ}{m}_{\max },1\}\\ {\mathrm{\δ}}_{C\_\min }=\max \{-\mathrm{\λ}{m}_{\min },0\}\end{array}\right.---\left(4\right)$

6) divide the zero vector principle of action time according to waiting, determined the final duty cycle, delta of brachium pontis C by formula (5) _C:

${\mathrm{\δ}}_C=\frac{{\mathrm{\δ}}_{C\_\max }+{\mathrm{\δ}}_{C\_\min }}{2}---\left(5\right)$

7) obtain again the duty ratio of each brachium pontis according to formula (6):

$\left\{\begin{array}{c}{\mathrm{\δ}}_A=\mathrm{\λ}{m}_{\mathrm{AC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_B=\mathrm{\λ}{m}_{\mathrm{BC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_D=\mathrm{\λ}{m}_{\mathrm{DC}}+{\mathrm{\δ}}_C\\ {\mathrm{\δ}}_E=\mathrm{\λ}{m}_{\mathrm{EC}}+{\mathrm{\δ}}_C\end{array}\right.---\left(6\right)$

In the formula, δ _A, δ _B, δ _C, δ _D, δ _EBe respectively the duty ratio of brachium pontis A, B, C, D, E, according to the duty ratio of five brachium pontis determining, control when realizing Five-phase inverter to two three phase electric machines.

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