阅读说明：本技术 适用于三相双输入逆变器的扇区自适应空间矢量调制方法 (Sector adaptive space vector modulation method suitable for three-phase dual-input inverter ) 是由 尹航 葛红娟 于兆龙 李言 潘怡晨 李石振 于 2019-09-19 设计创作，主要内容包括：本发明公开了一种针对三相双输入双Buck逆变器的新型子扇区自适应的间矢量脉宽调制技术(SVPWM),属于直-交电能变换技术领域。本发明以双输入高压V<Sub>H</Sub>的值为基础确定六个主扇区的主矢量长度,依据双输入高、低电压源V<Sub>H</Sub>和V<Sub>L</Sub>将每个主扇区划分为四个子扇区,共形成24个子扇区,每个子扇区对应三个长度与V<Sub>H</Sub>和V<Sub>L</Sub>有关的子矢量；以三个子矢量、目标旋转矢量和开关周期为基础,解算每个子矢量的作用时间；根据子矢量的类型和作用时间,确定电压矢量的作用顺序,进行SVPWM调制。与目前的双载波调制方法相比,本发明引入SVPWM技术,提高了直流电压利用率,同时保留了双输入逆变器系统效率高的优点。(The invention discloses a novel sub-sector self-adaptive Space Vector Pulse Width Modulation (SVPWM) technology for a three-phase double-input double-Buck inverter, and belongs to the technical field of direct-alternating current (DC-AC) power conversion. The invention uses double input high voltage V H Determines the lengths of the principal vectors of the six principal sectors based on the values of (V) and (V) of the two input high and low voltage sources H And V L Dividing each main sector into four sub-sectors, forming 24 sub-sectors, each sub-sector corresponding to three lengths and V H And V L A related sub-vector; calculating the action time of each sub-vector on the basis of the three sub-vectors, the target rotation vector and the switching period; and determining the action sequence of the voltage vector according to the type and the action time of the sub-vector, and carrying out SVPWM modulation. Compared with the existing double-carrier modulation method, the SVPWM technology is introduced, the direct-current voltage utilization rate is improved, and the advantage of high efficiency of a double-input inverter system is kept.)

1. The invention discloses a novel sub-sector adaptive Space Vector Pulse Width Modulation (SVPWM) method aiming at a three-phase dual-input dual-Buck inverter topology, which is characterized in that a dual-input high-voltage V is adopted_HDetermining the main vector length of the six main sectors I, II, III, VI, V and VI of the SVPWM on the basis of the value of the SVPWM, and for each main sector, determining the length of the main vector according to a double-input high-low voltage source V_HAnd V_LDividing the sector into four sub-sectors of x-1, x-2, x-3 and x-4, wherein x is an I sector, or II, or III, or VI, or V, or VI sector; according to the rotation vector amplitude V required to be synthesized in SVPWM_refComponent V in the alpha and beta axes, respectively_α、V_βJudging the main sector and the sub-sector to which the rotation vector belongs, wherein each sub-sector is determined by three sub-vectors; three sub-vectors per sub-sector, a target rotation vector and a switching period T_sThe action time T of each sub-vector can be solved₁、T₂And T₃Wherein T is₁Indicating the first within a switching cycleVector of action, T₃A vector representing the last action in a switching cycle; and in a switching period, determining the action sequence of the voltage vector according to the five-segment principle according to the type of the sub-vector in each sub-sector, and then completing SVPWM modulation.

2. The method of claim 1, wherein each main sector is based on a dual input high and low voltage source V_HAnd V_LDividing the vector into four sub-sectors of x-1, x-2, x-3 and x-4, wherein x is an I sector, or II, or III, or IV, or V, or VI sector, and totally 24 sub-sectors, and then according to the amplitude V of the rotation vector_refComponent V in the alpha beta axis respectively_α、V_βThe size of the rotation vector is judged, and the sub-sector V to which the rotation vector belongs is judged_HAnd V_LIs different in size, wherein V is_α、V_βIs determined according to the following formula, where theta is the argument of the rotation vector to be synthesized,

the judgment condition of the sub-sector is as follows:

the judgment of the sub-sectors of the IV, V and VI sectors is respectively symmetrical to the III, II and I sectors about the alpha axis, and only the judgment condition V needs to be considered_βIs replaced by-V_β。

3. The method as claimed in claim 1, wherein the vector of the three vertexes of the sub-sector where the target rotation vector is located is synthesizedRotating the target vector to determine the action time T of three sub-vectors in each sub-sector₁、T₂、T₃Wherein the specific action time of each vector is shown in the following table:

Technical Field

The invention relates to a modulation method of a three-phase dual-input inverter, belongs to the field of power electronics, and particularly relates to the technical field of space vector modulation.

Background

Because the output voltage is closer to a sine wave, the voltage stress borne by a switching device is smaller, the output current waveform quality is high and the like, the multi-level inverter becomes the hot invention content of people research gradually in recent years, and is widely applied to the power electronic application fields of solar energy, wind energy, electric transmission and the like.

On the other hand, patent "publication No.: CN105099249A "proposes a concept of a dual-input inverter, in which an auxiliary dc voltage source with a lower amplitude than a main dc voltage source is added to form a three-port converter, and the inverter can output three different levels by using two input sources, thereby reducing the harmonic content of the output voltage.

The common modulation method is divided into SPWM modulation and SVPWM space vector modulation, the existing modulation method of the inverter is dual-carrier modulation based on SPWM, however, the space vector modulation has the advantages of high direct-current voltage utilization rate, easier digitization of the modulation process and the like, and therefore, the inverter is widely applied.

Disclosure of Invention

The invention discloses a novel sub-sector adaptive Space Vector Pulse Width Modulation (SVPWM) method aiming at a three-phase dual-input dual-Buck inverter topology, which is characterized in that a dual-input high-voltage V is adopted_HDetermining the main vector length of the six main sectors I, II, III, VI, V and VI of the SVPWM on the basis of the value of the SVPWM, and for each main sector, determining the length of the main vector according to a double-input high-low voltage source V_HAnd V_LDividing the sector into four sub-sectors of x-1, x-2, x-3 and x-4, wherein x is an I sector, or II, or III, or VI, or V, or VI sector; according to the rotation vector amplitude V required to be synthesized in SVPWM_refComponent V in the alpha and beta axes, respectively_α、V_βJudging the main sector and the sub-sector to which the rotation vector belongs, wherein each sub-sector is determined by three sub-vectors; three sub-vectors per sub-sector, a target rotation vector and a switching period T_sThe action time T of each sub-vector can be solved₁、T₂And T₃Wherein T is₁Vector, T, representing the first contribution in a switching cycle₃Representing a switching cycleVector of inner last effort; and in a switching period, determining the action sequence of the voltage vector according to the five-segment principle according to the type of the sub-vector in each sub-sector, and then completing SVPWM modulation.

According to the sub-sector adaptive space vector pulse width modulation method, for each main sector, a dual-input high and low voltage source V can be used_HAnd V_LDividing the vector into four sub-sectors of x-1, x-2, x-3 and x-4, wherein x is an I sector, or II, or III, or IV, or V, or VI sector, and totally 24 sub-sectors, and then according to the amplitude V of the rotation vector_refComponent V in the alpha beta axis respectively_α、V_βIs determined, the sub-sector to which the rotation vector belongs, where V_HAnd V_LIs different in size, wherein V is_α、V_βDetermining according to the following formula, wherein theta is the amplitude angle of the rotation vector required to be synthesized;

the judgment condition of the sub-sector is as follows:

the judgment of the sub-sectors of the IV, V and VI sectors is respectively symmetrical to the III, II and I sectors about the Y axis, and only the judgment condition V needs to be considered_βIs replaced by-V_β。

According to the above-mentioned sub-sector adaptive space vector pulse width modulation method, the target rotation vector is synthesized by the vectors of the three vertexes of the sub-sector where the target rotation vector is located, thereby determining the action time T of the three sub-vectors in each sub-sector₁、T₂、T₃Wherein the specific action time of each vector is shown in the following table:

has the advantages that:

(1) the invention enriches the modulation strategy of the double-input three-phase inverter, improves the utilization rate of direct-current voltage, has lower switching loss and lower harmonic content.

(2) The invention is suitable for various types of double-input three-phase inverters, has wide application range and is easy to understand, and provides great convenience for the subsequent fault-tolerant control research due to the existence of the redundant vector.

(3) The modulation method avoids the use of a voltage division capacitor, not only reduces the volume and weight of the inverter, but also does not need to consider the voltage balance problem of the voltage division capacitor.

(4) The invention has strong practicability, convenient digital realization, good use effect and convenient popularization and use.

Drawings

FIG. 1 is a schematic diagram of a first dual-input three-phase dual-Buck inverter circuit to which the present invention is applied;

FIG. 2 is a schematic diagram of a second dual-input three-phase dual-Buck inverter circuit to which the present invention is applied;

FIG. 3 is a schematic diagram of a third dual-input three-phase dual-Buck inverter circuit to which the present invention is applied;

FIG. 4 is a schematic voltage vector space diagram of a dual-input three-phase dual-Buck inverter circuit;

FIG. 5 is a sub-sector division diagram of a voltage vector space of a dual-input three-phase dual-Buck inverter circuit in an I sector;

FIG. 6 is a SVPWM waveform diagram for sector I-2;

Detailed Description

The modulation technique of the present invention will be described in detail below with reference to the drawings.

The converter applied by the invention mainly comprises three topologies shown in fig. 1, 2 and 3, and is composed of a dual-input source (V)_H、V_L) 12 switch tubes (S)_a1～S_a4、S_b1～S_b4、S_c1～S_c4) 12 diodes (D)_a1～D_a4、D_b1～D_b4、D_c1～D_c4) 6 filter inductors and 3 filter capacitors, wherein the A-phase bridge arm consists of S_a1、S_a2、S_a3、S_a4、D_a1、D_a2、D_a3、D_a4The bridge arm output is via L_a1、L_a2The filter inductor outputs the filter inductor to a load; bridge arm of B phase is composed of S_b1、S_b2、S_b3、S_b4、D_b1、D_b2、D_b3、D_b4The bridge arm output is via L_b1、L_b2The filter inductor outputs the filter inductor to a load; c-phase bridge arm composed of S_c1、S_c2、S_c3、S_c4、D_c1、D_c2、D_c3、D_c4The bridge arm output is via L_c1、L_c2The filter inductor outputs to the load.

For a double-input three-phase inverter, each bridge arm can output three voltages, respectively V_H、V_LAnd 0, analyzing the topological switch mode to obtain the relation between the topological switch mode and the bridge arm output, which is shown in the following table:

Sx1	Sx2	Sx3	Sx4	bridge arm output
					1	1	0	0	VH
0	1	1	0	VL
					0	0	1	1	0

Wherein 1 represents that the switch is closed, 0 represents that the switch is opened, and x can be any one of a, b and c.

Each bridge arm can output three levels according to a voltage vector calculation formula

Can calculate 3³All vectors are shown in fig. 4, where 6 are the main vectors and the magnitude is 27There are 12 short vectors, of which 6 have amplitudes ofAnother 6 amplitudes areThe number of the medium vectors is 6, and the amplitude isThere are 3 zero vectors. For convenience of explanation, the magnitude relation of two short vectors on each main vector is specified, and requirements are madeCan obtain

And then, carrying out main sector division, wherein the main sector division is carried out according to the following division conditions:

sector area	Range of central angle
		I	0°＜θ≤60°
II	60°＜θ≤120°
		III	120°＜θ≤180°
IV	180°＜θ≤240°
		V	240°＜θ≤300°
VI	300°＜θ≤360°

Where θ is the argument of the desired resultant voltage vector.

After the division of the main sector is finished, the sub-sector division is carried out, the division is divided in a plane rectangular coordinate system according to the following sector allocation table, and the coordinate (V) of the reference vector in an alpha beta coordinate system is calculated by the following formula_α，V_β) Wherein V is_refIs the magnitude of the desired resultant voltage vector.

Sub-sector judgment table:

the judgment of the sub-sectors of the IV, V and VI sectors is respectively symmetrical to the III, II and I sectors about the alpha axis, and only the judgment condition V needs to be considered_βIs replaced by-V_βThe result of the sub-sector division is shown in fig. 5.

After the sector is judged, synthesizing a reference vector by using the sub-vectors of three vertexes of a triangle where the vector is located according to the volt-second balance principle, for example, in an I-2 sector, synthesizing a target vector by using a PON, an OON and a POO, and synthesizing according to a formula T_s·V_ref＝T₁·V₁+T₂·V₂+T₃·V₃To determine the action time T of three sub-vectors₁、T₂、T₃：

Determining a vector sending sequence according to a five-segment formula according to the type of each sub-sector action vector, wherein the vector sending sequence is shown in the following table,

after the vector sending sequence is determined, the conduction time of each switch tube is determined according to the action time of each vector, and FIG. 6 is an SVPWM waveform diagram of a reference vector in an I-2 area, wherein T is a triangular carrier wave and a three-phase output voltage waveform_a1、T_b1、T_c1、T_a2、T_b2、T_c2Three comparison values respectively compared with the triangular carrier wave to generate the PWM waveCorresponding to switch S_a1、S_b1、S_c1、S_a2、S_b2、S_c2The remaining S_a3、S_b3、S_c3、S_a4、S_b4、S_c4Driving PWM wave of different from S_a1、S_b1、S_c1、S_a2、S_b2、S_c2Complementation is therefore not described. Supposing that the amplitude and the period of the triangular carrier wave are equal, when the carrier wave is larger than the counting value, a high level is output, otherwise, a low level is output, the area is specifically explained, the reference vector is synthesized by three base vectors of POO, PON and OON in the area, and T is provided for the duration time of each vector_a1＝T₁、T_a2＝0，T_b1＝T_s，T_b2＝0，T_c1＝T_s，T_b2＝T_s-T₃. Wherein T is₁Is the vector OON action time, T₃Is the vector POO action time. Finally, SVPWM modulation can be completed according to the illustration principle, and the modulation principle of each other sub-sector is the same.