阅读说明：本技术 一种电磁兼容友好型开绕组拓扑结构 (Electromagnetic compatibility friendly open winding topological structure ) 是由 杨淑英 李�一 王付胜 谢震 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种电磁兼容友好型开绕组拓扑结构,属于开绕组电机控制领域。所述拓扑结构将一个滤波电容的两端分别与两侧三相两电平逆变器的直流母线中点相连,构成中线带滤波电容的共中线开绕组拓扑结构。该拓扑保持了高频信号在中线上的流通,使得两侧三相两电平逆变器母线间不存在高频电压脉动；同时削弱了低频零序环流在中线流通的能力,从而减轻系统控制过程中因抑制低频零序环流而产生的共模电压负担,提高了开绕组系统电磁兼容性,系统的控制性能也得到提升。(The invention discloses an electromagnetic compatibility friendly open winding topological structure, and belongs to the field of open winding motor control. The topological structure is characterized in that two ends of a filter capacitor are respectively connected with the middle points of direct current buses of three-phase two-level inverters on two sides, so that a common neutral line open winding topological structure with a neutral line provided with the filter capacitor is formed. The topology keeps the circulation of high-frequency signals on a central line, so that high-frequency voltage pulsation does not exist between buses of the three-phase two-level inverter on two sides; meanwhile, the circulation capacity of the low-frequency zero-sequence circulation current in the neutral line is weakened, so that the common-mode voltage burden generated by inhibiting the low-frequency zero-sequence circulation current in the control process of the system is reduced, the electromagnetic compatibility of the open winding system is improved, and the control performance of the system is also improved.)

1. An electromagnetic compatibility friendly open winding topological structure is characterized by comprising a direct current source E, a first three-phase two-level inverter VSI1, a second three-phase two-level inverter VSI2, a motor three-phase stator winding D, a neutral line N, a filter capacitor C, an electrolytic capacitor C1, an electrolytic capacitor C2, an electrolytic capacitor C3 and an electrolytic capacitor C4;

the electrolytic capacitor C1 and the electrolytic capacitor C2 are connected in series and then connected between a direct current positive bus P and a direct current negative bus Q of a direct current source E, and a common joint of the electrolytic capacitor C1 and the electrolytic capacitor C2 is marked as a point O1; the electrolytic capacitor C3 is connected with the electrolytic capacitor C4 in series, a common node of the electrolytic capacitor C3 and the electrolytic capacitor C4 is marked as a point O2, the midline N is connected with a point O1 and a point O2, and the filter capacitor C is connected between the point O1 and the point O2 in series;

in the three-phase bridge arm of the first three-phase two-level inverter VSI1, each phase of bridge arm includes 2 switching tubes, that is, the first three-phase two-level inverter VSI1 includes 6 switching tubes, and the 6 switching tubes are respectively marked as S_n1jWherein n represents the phase sequence, n is a, b, c, j represents the serial number of the switching tube, and j is 1, 2; the three-phase bridge arms of the first three-phase two-level inverter VSI1 are connected in parallel between the direct current positive bus P and the direct current negative bus Q, namely a switch tube S_a11、S_b11、S_c11The collectors are connected in parallel and then are connected with a direct current positive bus P and a switching tube S_a12、S_b12、S_c12The emitting electrodes are connected in parallel and then connected with a direct current negative bus Q; in the three-phase leg of the first three-phase two-level inverter VSI1, the switching tube S_a11And a switching tube S_a12Series, switch tube S_b11And a switching tube S_b12Series, switch tube S_c11And a switching tube S_c12The three-phase two-level inverter VSI1 is connected in series, and the connection points of the three-phase two-level inverter VSI1 are respectively marked as three-phase bridge arm middle points a1, b1 and c 1;

in the three-phase bridge arm of the second three-phase two-level inverter VSI2, each phase of bridge arm includes 2 switching tubes, that is, the second three-phase two-level inverter VSI2 includes 6 switching tubes, and the 6 switching tubes are respectively marked as S_n2j(ii) a Switch tube S_a21、S_b21、S_c21The collectors of the three-phase current transformer are connected in parallel and then connected with the anode of an electrolytic capacitor C3 and a switching tube S_a22、S_b22、S_c22The emitters are connected in parallel and then connected with the negative electrode of an electrolytic capacitor C4; in the three-phase leg of the second three-phase two-level inverter VSI2, the switching tube S_a21And a switching tube S_a22Series, switch tube S_b21And a switching tube S_b22Series, switch tube S_c21And a switching tube S_c22The three-phase bridge arms are connected in series, and the connection points of the three-phase bridge arms are respectively marked as three-phase bridge arm middle points a2, b2 and c2 of the second three-phase two-level inverter VSI 2;

the motor three-phase stator winding D comprises three-phase windings, namely an A-phase winding, a B-phase winding and a C-phase winding, wherein:

the left port of the A-phase winding is connected with a three-phase bridge arm midpoint a1 of a first three-phase two-level inverter VSI1, and the right port of the A-phase winding is connected with a three-phase bridge arm midpoint a2 of a second three-phase two-level inverter VSI 2;

the left port of the B-phase winding is connected with a three-phase bridge arm midpoint B1 of a first three-phase two-level inverter VSI1, and the right port of the B-phase winding is connected with a three-phase bridge arm midpoint B2 of a second three-phase two-level inverter VSI 2;

the left port of the C-phase winding is connected with a three-phase bridge arm midpoint C1 of the first three-phase two-level inverter VSI1, and the right port of the C-phase winding is connected with a three-phase bridge arm midpoint C2 of the second three-phase two-level inverter VSI 2.

Technical Field

The invention relates to the field of open winding motor control, in particular to an electromagnetic compatibility friendly open winding topological structure.

Background

Compared with the traditional single inverter system, the open winding motor system has the advantages of higher voltage utilization rate, easiness in realizing multi-source hybrid driving and the like, and is widely concerned by a plurality of scholars at home and abroad in recent years. At present, a common direct-current bus topological structure and an independent direct-current bus topological structure are mostly used for an open winding motor system, and for the common direct-current bus topological structure, multi-source hybrid driving cannot be realized; high-frequency voltage pulsation exists between buses of the independent direct-current bus topology, and safety problems such as electromagnetic interference and shaft current are caused. The common neutral line topology inhibits high-frequency voltage pulsation between buses by directly connecting the midpoints of the bus power supplies on the two sides, and has the advantages of a common direct current bus topology structure and an independent direct current bus topology structure. However, because a zero-sequence path still exists in the open-winding motor system under the common neutral line topology, the circulation of zero-sequence circulation in the system becomes possible, the electromagnetic compatibility becomes poor, and the zero-sequence circulation can cause the distortion of motor phase current, and extra loss and torque pulsation are generated when the motor phase current is serious.

An article entitled "open winding asynchronous motor control strategy research based on common neutral topology" (the Chinese Motor engineering journal, No. 40, No. 11, 3681 and page 3691 in 2020). The article analyzes and researches the control strategy of the open-winding asynchronous motor under the common neutral line topology, zero-sequence circulation current still needs to be restrained due to the existence of a zero-sequence path under the topology, and the restraining method is basically similar to the common direct current bus topology.

An article entitled "Zero-Sequence Current Suppression Strategy With Common DC Bus Based on Zero Vector Redistribution" (Y.ZHOU and H.Nian, IEEE Transactions on Industrial Electronics, vol.62, No.6, pp.3399-3408, June 2015.) ("Zero-Sequence circulation Suppression Strategy for a Common DC Open-Winding permanent magnet synchronous Motor Based on Zero Vector Redistribution" (Y.ZHOU and H.Nian, proceedings of the institute of Electrical and Electronics Engineers industries, 2015 vol.62, No.6, No. 3399-3408)). The paper analyzes a zero sequence equivalent circuit of the open winding permanent magnet synchronous motor and indicates that the influence factors of the zero sequence circulation of the open winding permanent magnet synchronous motor are different from those of an asynchronous motor. Due to the existence of the three zero-sequence counter electromotive forces in the permanent magnet motor, the suppression of the zero-sequence circulating current is more complex compared with an asynchronous motor.

An article entitled "Control Strategies for Open-End Winding Operating in the Flux-influencing Region" (Sandulescu, f.meidinguet, x.kesteyn, e.semail and a.bruy fre, IEEE Transactions on Power Electronics, vol.29, No.9, pp.4829-4842, sept.2014.) ("weak magnetic area Open Winding drive Control strategy" (Sandulescu, f.meidinguet, x.kesteyn, e.semai and a.bruy tre, institute of electrical and Electronics engineers, vol.29, No.9, No. 4829-4842)). The article proposes that when an open-winding permanent magnet synchronous motor under a common direct current bus topology works in a weak magnetic region, zero-sequence circulating current of the motor is increased, so that the requirement of common-mode voltage modulation is increased, and the direct current voltage utilization rate is influenced.

In summary, the existing topology has the following problems:

1. similar to the common direct current bus topology, for a common neutral line topology open winding motor system, particularly for a permanent magnet synchronous motor system, a zero sequence loop contains a third harmonic back electromotive force generated by a rotor permanent magnet flux linkage, so that the suppression of zero sequence circulating current becomes difficult; when the motor operates under the working condition of large zero-sequence circulating current, the large zero-sequence circulating current is restrained by only depending on a control means, the electromagnetic compatibility is deteriorated at the cost of modulating large common-mode voltage by the inverter, and the modulation of differential-mode voltage is influenced, so that the control performance of a motor system is deteriorated.

Disclosure of Invention

The invention aims to solve the problem of zero-sequence circulating current of a common neutral open-winding motor system, inhibit the circulating capacity of low-frequency zero-sequence circulating current in the system and reduce the common-mode voltage modulation burden caused by the inhibition of the low-frequency zero-sequence circulating current in the control process of the system.

The invention aims to realize the purpose, two ends of a filter capacitor are respectively connected with the middle points of direct current buses of three-phase two-level inverters at two sides, so that the filter capacitor keeps the circulation of high-frequency signals and inhibits the circulation of low-frequency zero-sequence signals, and a topological structure with the filter capacitor at the center line and capable of inhibiting the low-frequency zero-sequence circulating current of a common-center-line open-winding motor is formed.

Specifically, the invention provides an electromagnetic compatibility friendly open winding topological structure, which comprises a direct current source E, a first three-phase two-level inverter VSI1, a second three-phase two-level inverter VSI2, a motor three-phase stator winding D, a neutral line N, a filter capacitor C, an electrolytic capacitor C1, an electrolytic capacitor C2, an electrolytic capacitor C3 and an electrolytic capacitor C4;

the electrolytic capacitor C1 and the electrolytic capacitor C2 are connected in series and then connected between a direct current positive bus P and a direct current negative bus Q of a direct current source E, and a common joint of the electrolytic capacitor C1 and the electrolytic capacitor C2 is marked as a point O1; the electrolytic capacitor C3 is connected with the electrolytic capacitor C4 in series, a common node of the electrolytic capacitor C3 and the electrolytic capacitor C4 is marked as a point O2, the midline N is connected with a point O1 and a point O2, and the filter capacitor C is connected between the point O1 and the point O2 in series;

in the three-phase bridge arm of the first three-phase two-level inverter VSI1, each phase of bridge arm includes 2 switching tubes, that is, the first three-phase two-level inverter VSI1 includes 6 switching tubes, and the 6 switching tubes are respectively marked as S_n1jWherein n represents the phase sequence, n is a, b, c, j represents the serial number of the switching tube, and j is 1, 2; the three-phase bridge arms of the first three-phase two-level inverter VSI1 are connected in parallel between the direct current positive bus P and the direct current negative bus Q, namely a switch tube S_a11、S_b11、S_c11The collectors are connected in parallel and then are connected with a direct current positive bus P and a switching tube S_a12、S_b12、S_c12The emitting electrodes are connected in parallel and then connected with a direct current negative bus Q; in the three-phase leg of the first three-phase two-level inverter VSI1, the switching tube S_a11And a switching tube S_a12Series, switch tube S_b11And a switching tube S_b12Series, switch tube S_c11And a switching tube S_c12The three-phase two-level inverter VSI1 is connected in series, and the connection points of the three-phase two-level inverter VSI1 are respectively marked as three-phase bridge arm middle points a1, b1 and c 1;

three of the second three-phase two-level inverter VSI2In the phase bridge arms, each phase bridge arm includes 2 switching tubes, that is, the second three-phase two-level inverter VSI2 includes 6 switching tubes in total, and the 6 switching tubes are respectively marked as S_n2j(ii) a Switch tube S_a21、S_b21、S_c21The collectors of the three-phase current transformer are connected in parallel and then connected with the anode of an electrolytic capacitor C3 and a switching tube S_a22、S_b22、S_c22The emitters are connected in parallel and then connected with the negative electrode of an electrolytic capacitor C4; in the three-phase leg of the second three-phase two-level inverter VSI2, the switching tube S_a21And a switching tube S_a22Series, switch tube S_b21And a switching tube S_b22Series, switch tube S_c21And a switching tube S_c22The three-phase bridge arms are connected in series, and the connection points of the three-phase bridge arms are respectively marked as three-phase bridge arm middle points a2, b2 and c2 of the second three-phase two-level inverter VSI 2;

the motor three-phase stator winding D comprises three-phase windings, namely an A-phase winding, a B-phase winding and a C-phase winding, wherein:

the left port of the A-phase winding is connected with a three-phase bridge arm midpoint a1 of a first three-phase two-level inverter VSI1, and the right port of the A-phase winding is connected with a three-phase bridge arm midpoint a2 of a second three-phase two-level inverter VSI 2;

the left port of the B-phase winding is connected with a three-phase bridge arm midpoint B1 of a first three-phase two-level inverter VSI1, and the right port of the B-phase winding is connected with a three-phase bridge arm midpoint B2 of a second three-phase two-level inverter VSI 2;

the left port of the C-phase winding is connected with a three-phase bridge arm midpoint C1 of the first three-phase two-level inverter VSI1, and the right port of the C-phase winding is connected with a three-phase bridge arm midpoint C2 of the second three-phase two-level inverter VSI 2.

Compared with the prior art, the invention has the beneficial effects that:

1. compared with the existing common neutral line topology open-winding motor system, the topology can inhibit the circulation capacity of low-frequency zero-sequence circulating current in the system, the amplitude of the required common-mode voltage is lower under the same operation condition, and the electromagnetic compatibility is better;

2. the lower common mode voltage modulation requirement improves the control performance of the system.

Drawings

Fig. 1 is a topological structure diagram of an electromagnetic compatibility friendly open winding topological structure of the present invention.

Fig. 2 shows the experimental results of zero-sequence circulating current and common-mode voltage in the existing common-neutral-line topology open-winding permanent magnet synchronous motor control system.

Fig. 3 is a result of the zero-sequence circulating current and common-mode voltage experiment in the topology open-winding permanent magnet synchronous motor control system of the present invention under the same experimental conditions as fig. 2.

Detailed Description

The following describes an electromagnetic compatibility friendly open winding topology according to the present invention in detail with reference to the accompanying drawings and embodiments.

Fig. 1 is a topological structure diagram of an electromagnetic compatibility friendly open winding topological structure of the present invention. As can be seen from fig. 1, the invention provides an electromagnetic compatibility friendly open winding topology structure, which comprises a direct current source E, a first three-phase two-level inverter VSI1, a second three-phase two-level inverter VSI2, a motor three-phase stator winding D, a neutral line N, a filter capacitor C, an electrolytic capacitor C1, an electrolytic capacitor C2, an electrolytic capacitor C3 and an electrolytic capacitor C4.

The electrolytic capacitor C1 and the electrolytic capacitor C2 are connected in series and then connected between a direct current positive bus P and a direct current negative bus Q of a direct current source E, and a common joint of the electrolytic capacitor C1 and the electrolytic capacitor C2 is marked as a point O1; the electrolytic capacitor C3 is connected with the electrolytic capacitor C4 in series, a common node of the electrolytic capacitor C3 and the electrolytic capacitor C4 is marked as a point O2, the midline N is connected with a point O1 and a point O2, and the filter capacitor C is connected between the point O1 and the point O2 in series.

In the three-phase bridge arm of the first three-phase two-level inverter VSI1, each phase of bridge arm includes 2 switching tubes, that is, the first three-phase two-level inverter VSI1 includes 6 switching tubes, and the 6 switching tubes are respectively marked as S_n1jWherein n represents the phase sequence, n is a, b, c, j represents the serial number of the switching tube, and j is 1, 2; the three-phase bridge arms of the first three-phase two-level inverter VSI1 are connected in parallel between the direct current positive bus P and the direct current negative bus Q, namely a switch tube S_a11、S_b11、S_c11The collectors are connected in parallel and then are connected with a direct current positive bus P and a switching tube S_a12、S_b12、S_c12The emitting electrodes are connected in parallel and then connected with a direct current negative bus Q; in the first three-phase two-phaseIn three-phase bridge arm of flat inverter VSI1, switching tube S_a11And a switching tube S_a12Series, switch tube S_b11And a switching tube S_b12Series, switch tube S_c11And a switching tube S_c12The connection points of the series are respectively marked as three-phase arm middle points a1, b1 and c1 of the first three-phase two-level inverter VSI 1.

In the three-phase bridge arm of the second three-phase two-level inverter VSI2, each phase of bridge arm includes 2 switching tubes, that is, the second three-phase two-level inverter VSI2 includes 6 switching tubes, and the 6 switching tubes are respectively marked as S_n2j(ii) a Switch tube S_a21、S_b21、S_c21The collectors of the three-phase current transformer are connected in parallel and then connected with the anode of an electrolytic capacitor C3 and a switching tube S_a22、S_b22、S_c22The emitters are connected in parallel and then connected with the negative electrode of an electrolytic capacitor C4; in the three-phase leg of the second three-phase two-level inverter VSI2, the switching tube S_a21And a switching tube S_a22Series, switch tube S_b21And a switching tube S_b22Series, switch tube S_c21And a switching tube S_c22The connection points of the series are respectively marked as three-phase arm middle points a2, b2 and c2 of the second three-phase two-level inverter VSI 2.

The motor three-phase stator winding D comprises three-phase windings, namely an A-phase winding, a B-phase winding and a C-phase winding, wherein:

the left port of the A-phase winding is connected with a three-phase bridge arm midpoint a1 of a first three-phase two-level inverter VSI1, and the right port of the A-phase winding is connected with a three-phase bridge arm midpoint a2 of a second three-phase two-level inverter VSI 2;

the left port of the B-phase winding is connected with a three-phase bridge arm midpoint B1 of a first three-phase two-level inverter VSI1, and the right port of the B-phase winding is connected with a three-phase bridge arm midpoint B2 of a second three-phase two-level inverter VSI 2;

the left port of the C-phase winding is connected with a three-phase bridge arm midpoint C1 of the first three-phase two-level inverter VSI1, and the right port of the C-phase winding is connected with a three-phase bridge arm midpoint C2 of the second three-phase two-level inverter VSI 2.

In order to verify the effectiveness of the invention, the invention was experimentally verified. The parameters of the experimental system are as follows: the direct current source E is 400V, the direct current voltage on the VSI2 side of the second three-phase two-level inverter is set to be 400V, the capacitance values of the electrolytic capacitor C1, the electrolytic capacitor C2, the electrolytic capacitor C3 and the electrolytic capacitor C4 are all 2048 muF, and the neutral filter capacitor C is designed to be 3.3 muF. The results of the experiment were recorded when the motor was operated at 30 hz.

Fig. 2 shows the experimental results of zero-sequence circulating current and common-mode voltage in the existing common-neutral-line topology open-winding permanent magnet synchronous motor control system.

Fig. 3 is a result of the zero-sequence circulating current and common-mode voltage experiment in the topology open-winding permanent magnet synchronous motor control system of the present invention under the same experimental conditions as fig. 2.

Comparing the experimental results of fig. 2 and fig. 3, it is seen that, due to the effect of the filter capacitor C in the topology of the present invention, while the zero-sequence circulating current fluctuates substantially near 0A, the amplitude of the common-mode voltage in the existing common-neutral line topology is about 45V, while the amplitude of the common-mode voltage in the topology of the present invention is only about 15V; the counter electromotive force of the experimental motor comprises 3-order and 15-order harmonics, and it can be seen from fig. 2 and 3 that the common-mode voltage is represented by the superposition of the 3-order and 15-order harmonics, which indicates that both the low-frequency zero-sequence components can be suppressed.

The application of the topological structure is explained to be capable of effectively inhibiting low-frequency zero-sequence circulating currents in the open-winding motor system, and the common-mode voltage amplitude value generated by inhibiting the low-frequency zero-sequence circulating currents in the system is greatly reduced, so that the electromagnetic interference generated by common-mode signals is weakened, and the control performance of the system is also improved.