CN205430084U

CN205430084U - Many three inverter's on T type of SHEPWM modulation zero sequence circulation restraint system

Info

Publication number: CN205430084U
Application number: CN201620270851.2U
Authority: CN
Inventors: 张承慧; 张桐盛; 陈阿莲; 杜春水; 潘羿威; 邢相洋
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2016-04-01
Filing date: 2016-04-01
Publication date: 2016-08-03
Anticipated expiration: 2026-04-01

Abstract

The utility model discloses a zero-sequence circulation suppression system of multiple T-type three-level inverters modulated by SHEPWM. This method can eliminate more harmonics on the AC side of the system output with the same number of switching angles; when the same number of harmonics is required to be eliminated on the AC side, the number of switching times is lower than that of the traditional system, and the switching loss is smaller. The method effectively suppresses the zero-sequence circulating current between the inverters, and improves the efficiency and stability of the overall operation of the system. This system does not need to add additional devices and control algorithms, it only needs to change the switch angle of SHEPWM pre-stored in the system, which is simple and easy.

Description

Zero-sequence circulating current suppression system for multiple T-type three-level inverters modulated by SHEPWM

技术领域technical field

本实用新型涉及一种SHEPWM调制的多台T型三电平逆变器的零序环流抑制系统。The utility model relates to a zero-sequence circulation suppression system of multiple T-type three-level inverters modulated by SHEPWM.

背景技术Background technique

随着国家对新能源的重视程度不断增加，光伏产业近几年发展非常迅速，在低压可再生能源发电系统中，多电平逆变器得到了越来越广泛的研究和使用。其输出交流电压有较低的dv/dt，较低的谐波畸变率，相比传统两电平逆变器有较低的器件开关应力，并可进一步降低开关器件的电压等级。三电平逆变器的拓扑结构如中点钳位型(NPC)、飞跨电容型和级联H桥型等，其中NPC型使用最为广泛，并以此为基础出现了诸多改进拓扑，特别是近来提出的T型拓扑。With the country's increasing emphasis on new energy, the photovoltaic industry has developed very rapidly in recent years. In low-voltage renewable energy power generation systems, multi-level inverters have been more and more widely researched and used. Its output AC voltage has lower dv/dt, lower harmonic distortion rate, lower device switching stress than traditional two-level inverters, and can further reduce the voltage level of switching devices. The topologies of three-level inverters include neutral point clamp (NPC), flying capacitor and cascaded H-bridge, among which NPC is the most widely used, and based on this, many improved topologies have appeared, especially It is a recently proposed T-type topology.

单台T型三电平逆变器的功率受到器件额定功率等因素的限制，使得面对大功率应用场合时，单台T型三电平逆变器会不能满足要求。对于大功率应用如电机驱动、微电网、分布式发电系统等，逆变器并联是简单有效的方法。逆变器并联通常采用相互隔离的直流母线，或利用变压器产生隔离的交流母线，以切断零序环流的流通路径，达到并联运行目的。但这种硬件隔离的方法会增加系统成本和体积。共交直流母线的并联方法能极大程度减小系统开销，但相应的也会产生零序环流通路，零序环流如果不加以抑制，会产生极大的输出电流畸变，并带来无功和谐波损耗，严重影响系统运行的稳定性，甚至会给逆变器带来损坏。The power of a single T-type three-level inverter is limited by factors such as the rated power of the device, so that when facing high-power applications, a single T-type three-level inverter cannot meet the requirements. For high-power applications such as motor drives, micro-grids, distributed generation systems, etc., paralleling inverters is a simple and effective method. Parallel inverters usually use isolated DC buses, or use transformers to generate isolated AC buses to cut off the circulation path of zero-sequence circulating current and achieve the purpose of parallel operation. But this method of hardware isolation will increase system cost and size. The parallel connection method of the common AC and DC bus can greatly reduce the system overhead, but it will also generate a zero-sequence circulating current path. If the zero-sequence circulating current is not suppressed, it will generate a huge output current distortion and bring reactive power and Harmonic loss will seriously affect the stability of the system operation, and even cause damage to the inverter.

目前已有多种逆变器并联运行的方法。视逆变器控制与调制的方法不同，相应的环流抑制的方法也不相同。逆变器的调制有多种方法如正弦脉宽调制(SPWM)，空间矢量调制(SVPWM)，特定谐波消除法(SHEPWM)等。其中SHEPWM相对于SPWM和SVPWM具有开关频率小，开关损耗低，控制简单，软件开销小的优点；在特定谐波抑制方面，SHEPWM有显著的优点。这些特点使SHEPWM特别适合大功率应用。传统的SHEPWM调制的并联逆变器零序环流抑制的方法有控制零矢量和小矢量的方法，但这种方法提高了逆变器的开关频率。在尽可能保持SHEPWM优点的情况下，最大可能的抑制零序环流，对SHEPWM调制的T型三电平逆变器并联系统意义重大。At present, there are many methods for parallel operation of inverters. Depending on the method of inverter control and modulation, the corresponding methods of circulating current suppression are also different. There are many ways to modulate the inverter, such as sinusoidal pulse width modulation (SPWM), space vector modulation (SVPWM), specific harmonic elimination method (SHEPWM) and so on. Compared with SPWM and SVPWM, SHEPWM has the advantages of small switching frequency, low switching loss, simple control, and small software overhead; in terms of specific harmonic suppression, SHEPWM has significant advantages. These features make SHEPWM especially suitable for high power applications. The traditional SHEPWM modulated parallel inverter zero-sequence circulating current suppression method has the method of controlling zero vector and small vector, but this method increases the switching frequency of the inverter. In the case of keeping the advantages of SHEPWM as much as possible, the maximum possible suppression of zero-sequence circulating current is of great significance to the T-type three-level inverter parallel system modulated by SHEPWM.

实用新型内容Utility model content

本实用新型为了解决上述问题，提出了一种SHEPWM调制的多台T型三电平逆变器的零序环流抑制系统，本实用新型能够很好的提高系统性能，有效抑制并联系统环流。In order to solve the above problems, the utility model proposes a zero-sequence circulating current suppression system of multiple T-type three-level inverters modulated by SHEPWM. The utility model can well improve system performance and effectively suppress parallel system circulating current.

为了实现上述目的，本实用新型采用如下技术方案：In order to achieve the above object, the utility model adopts the following technical solutions:

一种SHEPWM调制的多台T型三电平逆变器的零序环流抑制系统，包括脉冲信号发生器、控制器、开关角控制器和T型三电平逆变器并联系统，其中，T型三电平逆变器并联系统，包括多个并联的T型三电平逆变器，所有T型三电平逆变器共用交直流母线，且所有T型三电平逆变器直流侧分裂电容的中点相连，所有T型三电平逆变器的交流侧经过滤波器滤波后并联连接；A zero-sequence circulating current suppression system for multiple T-type three-level inverters modulated by SHEPWM, including a pulse signal generator, a controller, a switching angle controller and a parallel connection system of T-type three-level inverters, wherein T Type three-level inverter parallel system, including multiple T-type three-level inverters in parallel, all T-type three-level inverters share the AC and DC bus, and all T-type three-level inverters The midpoints of the split capacitors are connected, and the AC sides of all T-type three-level inverters are filtered by filters and then connected in parallel;

所述脉冲信号发生器产生脉冲信号，发送给每个T型三电平逆变器，所述控制器通过SHEPWM调制方式控制T型三电平逆变器并联系统的开关器件的开断，所述开关角控制器控制每个T型三电平逆变器的开关角，切断零序环流各个频率分量通路。The pulse signal generator generates a pulse signal and sends it to each T-type three-level inverter, and the controller controls the on-off of the switching devices of the T-type three-level inverter parallel system through the SHEPWM modulation mode, so The switching angle controller controls the switching angle of each T-shaped three-level inverter, and cuts off the paths of various frequency components of the zero-sequence circulating current.

所述T型三电平逆变器，包括并联的三相桥臂，每相桥臂包括两个串联的IGBT管，各相桥臂的中点一侧串联两个方向不同的IGBT管，另一侧经滤波器与负载或电网连接；在并联的各桥臂输入端接入输入电压源；每台逆变器输入直流侧并联有两组电容，两组电容连接处连接各相桥臂的两个方向不同IGBT管的一端，各个IGBT管均由控制信号驱动。The T-type three-level inverter includes three-phase bridge arms connected in parallel, each phase bridge arm includes two IGBT tubes connected in series, two IGBT tubes in different directions are connected in series on one side of the midpoint of each phase bridge arm, and the other One side is connected to the load or grid through the filter; the input voltage source is connected to the input terminal of each bridge arm connected in parallel; two sets of capacitors are connected in parallel on the input DC side of each inverter, and the connections of the two sets of capacitors are connected to the bridge arms of each phase One end of the two IGBT tubes in different directions, and each IGBT tube is driven by a control signal.

优选的，所述控制器为解耦控制器，驱动T型三电平逆变器的每个IGBT管。Preferably, the controller is a decoupling controller, which drives each IGBT tube of the T-type three-level inverter.

优选的，所述T型三电平逆变器并联系统采用不同的开关角。Preferably, the T-type three-level inverter parallel system adopts different switching angles.

所述滤波器为电感。The filter is an inductor.

一种SHEPWM调制的多台T型三电平逆变器的零序环流抑制方法，具体包括：多台T型三电平逆变器采用不同的开关模式，即多台T型三电平逆变器的SHEPWM计算出的开关角不完全相同，根据要求的开关角的个数N及T型三电平逆变器的台数p，联立p×N个方程求解出开关角，使得每台T型三电平逆变器每四分之一周期中仍然有N个开关角，控制基波幅值以及N-1个谐波幅值，每台T型三电平逆变器都根据给定基波调制比M产生相同的基波分量后，保证各台T型三电平逆变器具有(N-1)个自由度，消除(N-1)个谐波。A zero-sequence circulating current suppression method for multiple T-type three-level inverters modulated by SHEPWM, specifically including: multiple T-type three-level inverters adopt different switching modes, that is, multiple T-type three-level inverters The switching angles calculated by SHEPWM of the inverter are not exactly the same. According to the required number N of switching angles and the number p of T-type three-level inverters, the switching angles are solved by combining p×N equations, so that each The T-type three-level inverter still has N switching angles in each quarter cycle, and controls the amplitude of the fundamental wave and the amplitude of N-1 harmonics. Each T-type three-level inverter is based on the given After the fundamental wave modulation ratio M is fixed to generate the same fundamental wave component, it is guaranteed that each T-type three-level inverter has (N-1) degrees of freedom and eliminates (N-1) harmonics.

具体的，计算每台T型三电平逆变器的SHEPWM开关角时，要考虑消除(3+6n)次谐波，n＝0,1,2…，要消除零序环流中m个分量，就增加p×m个方程和p×m个未知数，相应的每台T型三电平逆变器增加m个开关角，系统整体增加2m个开关角。Specifically, when calculating the SHEPWM switching angle of each T-type three-level inverter, it is necessary to consider eliminating (3+6n) harmonics, n=0,1,2..., and to eliminate m components in the zero-sequence circulating current , then p×m equations and p×m unknowns are added, correspondingly each T-type three-level inverter adds m switching angles, and the system as a whole increases 2m switching angles.

优选的，每台T型三电平逆变器m个开关角都用来切断零序环流各个频率分量通路，保证环流抑制效果。Preferably, the m switching angles of each T-type three-level inverter are used to cut off the channels of each frequency component of the zero-sequence circulating current to ensure the effect of suppressing the circulating current.

优选的，则p-1台逆变器增加的m个开关角用来切断零序环流各个频率分量通路，剩余一台逆变器增加的m个开关角用来消除交流母线上更多的谐波，保证交流母线电能质量。Preferably, the m switching angles added by p-1 inverters are used to cut off the channels of each frequency component of the zero-sequence circulating current, and the m switching angles added by the remaining one inverter are used to eliminate more harmonics on the AC bus. waves to ensure the power quality of the AC busbar.

本实用新型的有益效果为：The beneficial effects of the utility model are:

(1)在同样开关频率下，和传统方案相比，本实用新型可以在交流侧公共连接点出消除更多低次谐波；在交流侧要求同样谐波消除效果的情况下，本实用新型比传统方案开关次数更低，开关损耗更小；(1) Under the same switching frequency, compared with the traditional scheme, the utility model can eliminate more low-order harmonics at the common connection point of the AC side; when the AC side requires the same harmonic elimination effect, the utility model Compared with the traditional scheme, the switching times are lower and the switching loss is smaller;

(2)本实用新型可以对逆变器之间零序环流进行有效抑制，增强三电平逆变器并联运行的稳定性，提高系统整体运行的效率；(2) The utility model can effectively suppress the zero-sequence circulating current between the inverters, enhance the stability of the parallel operation of the three-level inverters, and improve the efficiency of the overall operation of the system;

(3)本实用新型无需增加额外器件和控制算法，只需要更改系统中预存的SHEPWM开关角度，简单易行。(3) The utility model does not need to add additional devices and control algorithms, and only needs to change the SHEPWM switch angle prestored in the system, which is simple and easy to implement.

附图说明Description of drawings

图1为多台T型三电平逆变器并联系统拓扑图；Figure 1 is a topology diagram of a parallel system with multiple T-type three-level inverters;

图2为两台T型三电平逆变器并联系统拓扑图；Figure 2 is a topology diagram of a parallel system with two T-type three-level inverters;

图3为三电平逆变器拓扑图；Figure 3 is a topology diagram of a three-level inverter;

图4为T型三电平逆变器SHEPWM的典型波形；Figure 4 is a typical waveform of the T-type three-level inverter SHEPWM;

图5(a)为方法一下第一台逆变器的输出线电压的仿真结果；Fig. 5(a) is the simulation result of the output line voltage of the first inverter;

图5(b)为方法一下第一台逆变器的输出线电压仿真结果的FFT分析；Figure 5(b) shows the FFT analysis of the output line voltage simulation results of the first inverter;

图6(a)为方法一下第二台逆变器的输出线电压的仿真结果；Fig. 6 (a) is the simulation result of the output line voltage of the second inverter;

图6(b)为方法一下第二台逆变器的输出线电压仿真结果的FFT分析；Figure 6(b) shows the FFT analysis of the simulation results of the output line voltage of the second inverter;

图7(a)为方法一下并联逆变器输出公共连接点处线电压的仿真结果；Fig. 7(a) is the simulation result of the line voltage at the output common connection point of parallel inverters in the first method;

图7(b)为方法一下并联逆变器输出公共连接点处线电压仿真结果的FFT分析；Figure 7(b) is the FFT analysis of the simulation results of the line voltage at the output common connection point of parallel inverters;

图8(a)为方法一下并联逆变器交流母线A相电流波形的仿真结果；Fig. 8 (a) is the simulation result of the A-phase current waveform of the parallel inverter AC bus;

图8(b)为方法一下并联逆变器交流母线A相电流波形仿真结果的FFT分析；Figure 8(b) is the FFT analysis of the simulation results of the A-phase current waveform of the parallel inverter AC bus;

图9(a)为方法一下并联逆变器没有抑制环流的仿真结果；Fig. 9(a) is the simulation result of the method 1 parallel inverter not suppressing the circulating current;

图9(b)为方法一下并联逆变器采用本实用新型的环流抑制方法后的仿真结果；Fig. 9 (b) is the simulation result after the parallel inverter adopts the circulation suppression method of the present utility model;

图10(a)为方法二下第一台逆变器的输出线电压的仿真结果；Fig. 10(a) is the simulation result of the output line voltage of the first inverter under the second method;

图10(b)为方法二下第一台逆变器的输出线电压仿真结果的FFT分析；Figure 10(b) is the FFT analysis of the simulation results of the output line voltage of the first inverter under the second method;

图11(a)为方法二下第二台逆变器的输出线电压的仿真结果；Fig. 11(a) is the simulation result of the output line voltage of the second inverter under the second method;

图11(b)为方法二下第二台逆变器的输出线电压仿真结果的FFT分析；Figure 11(b) is the FFT analysis of the simulation results of the output line voltage of the second inverter under the second method;

图12(a)为方法二下并联逆变器输出公共连接点处线电压的仿真结果；Fig. 12(a) is the simulation result of the line voltage at the output common connection point of parallel inverters under the second method;

图12(b)为方法二下并联逆变器输出公共连接点处线电压仿真结果的FFT分析；Figure 12(b) is the FFT analysis of the simulation results of the line voltage at the output common connection point of parallel inverters under the second method;

图13(a)为方法二下并联逆变器交流母线A相电流波形的仿真结果；Fig. 13(a) is the simulation result of the A-phase current waveform of the parallel inverter AC bus under the second method;

图13(b)为方法二下并联逆变器交流母线A相电流波形仿真结果的FFT分析；Figure 13(b) is the FFT analysis of the simulation results of the A-phase current waveform of the AC bus of the parallel inverter under the second method;

图14(a)为方法二下并联逆变器没有抑制环流的仿真结果；Fig. 14(a) is the simulation result of the parallel inverter not suppressing the circulating current under the second method;

图14(b)为方法二下并联逆变器采用本实用新型的环流抑制方法后的仿真结果。Fig. 14(b) is the simulation result after the parallel inverter adopts the circulating current suppression method of the utility model under the second method.

具体实施方式：detailed description:

下面结合附图与实施例对本实用新型作进一步说明。Below in conjunction with accompanying drawing and embodiment the utility model is further described.

多台三电平逆变器并联系统拓扑图如图1所示，在本实用新型中为了验证方法的可行性采用两台三电平逆变器并联系统拓扑图如图2所示，逆变器通过输出滤波电感共享交直流母线，P、N为并联系统的正负直流母线；A、B、C为并联系统的三相并网点；aj、bj、cj为第j台逆变器输出的交流端，滤波器采用L滤波器，滤波电感为L_j(j＝1,2,3,……p)，交流侧并网滤波电容为C_m，i_mj为第j台逆变器的m相输出电流，m＝a、b、c，j＝1,2,3,……p；i_A、i_B、i_C为系统并网电流。i_zj为第j台逆变器中的零序环流。The topology diagram of the parallel system of multiple three-level inverters is shown in Figure 1. In this utility model, the topology diagram of the parallel connection system of two three-level inverters is shown in Figure 2 in order to verify the feasibility of the method. The inverter shares the AC and DC buses through the output filter inductor, P and N are the positive and negative DC buses of the parallel system; A, B, and C are the three-phase grid connection points of the parallel system; aj, bj, and cj are the output of the jth inverter At the AC side, the filter adopts an L filter, the filter inductance is L _j (j=1,2,3,...p), the AC side grid-connected filter capacitor is C _m , and i _mj is the m of the jth inverter Phase output current, m=a, b, c, j=1,2,3,...p; i _A , i _B , i _C are grid-connected currents of the system. i _zj is the zero-sequence circulating current in the jth inverter.

以如图3所示单台逆变器结构阐述逆变器控制策略。单台T型三电平逆变器相电压V_xZ的SHEPWM波形如图4所示。波形四分之一周期对称，可消除电压波形中的偶次谐波分量。若指定四分之一周期内N个开关角，则基波与n次谐波的的幅值可利用傅里叶级数展开得到。对于图4所示SHEPWM波形，设波形具有单位幅值，该波形中基波与n次谐波幅值分别如式(1)、(2)。其中M为基波幅值调制比。The inverter control strategy is described with a single inverter structure as shown in Figure 3. The SHEPWM waveform of the phase voltage V _xZ of a single T-type three-level inverter is shown in Figure 4. The waveform is quarter-cycle symmetrical, which can eliminate even harmonic components in the voltage waveform. If N switching angles within a quarter cycle are specified, the amplitudes of the fundamental wave and the nth harmonic can be obtained by Fourier series expansion. For the SHEPWM waveform shown in Figure 4, it is assumed that the waveform has a unit amplitude, and the amplitudes of the fundamental wave and the nth harmonic in this waveform are shown in formulas (1) and (2) respectively. Where M is the modulation ratio of the fundamental amplitude.

$\frac{44}{π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} {cosα cosα}_{k k})) = = M m - - - - - - ((11))$

$\frac{44}{n no π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} c c o o s the s (({nα nα}_{k k})))) = = 00,, n no = = 55,, 77,, ... ...,, 33 N N - - 22 - - - - - - ((22))$

由于三相电压中三次谐波相位相同，故3次谐波与3的倍次谐波不考虑。所以四分之一周期中N个开关角可以控制基波幅值以及N-1个谐波幅值。定义为该SHEPWM具有(N–1)个自由度。多台逆变器都按照式(1)(2)计算出来的开关角进行开关，进而并联，即是传统的SHEPWM调制的三电平T型并联逆变器运行方法。在公共交流母线上可消除N-1个谐波。Since the phase of the third harmonic in the three-phase voltage is the same, the third harmonic and the third harmonic are not considered. So N switching angles in a quarter cycle can control the amplitude of the fundamental wave and the amplitude of N-1 harmonics. Defined as the SHEPWM has (N-1) degrees of freedom. Multiple inverters are switched according to the switching angle calculated by formula (1) (2), and then connected in parallel, which is the traditional operation method of three-level T-type parallel inverters modulated by SHEPWM. N-1 harmonics can be eliminated on the common AC bus.

本方案中，多台逆变器工作在不同的开关模式下，在开关角个数相同的情况下，尽可能多的消除公共交流母线上的特定谐波。这些特定谐波在公共交流母线上不存在，但可能会在单台逆变器的输出中存在。每台逆变器每四分之一周期中仍然有N个开关角，控制基波幅值以及N-1个谐波幅值。每台逆变器都根据给定基波调制比M产生相同的基波分量后，各台逆变器还有(N-1)个自由度，可消除(N-1)个谐波。这样p台并联系统在公共交流母线上可消除p×(N-1)个谐波，即有p×(N-1)个自由度。为了能消除p×(N-1)个谐波并控制基波分量，需要联立p×N个方程解出p×N个角，p×N个解中每台逆变器有N个开关角。系统整体开关频率不变，但可消除的谐波量增加数倍。以p＝2，N＝3为例，求解两台逆变器开关角的方程如式(3)。In this solution, multiple inverters work in different switching modes, and the specific harmonics on the common AC bus are eliminated as much as possible under the condition that the number of switching angles is the same. These specific harmonics do not exist on the common AC bus, but may exist in the output of a single inverter. Each inverter still has N switching angles in each quarter cycle to control the amplitude of the fundamental wave and the amplitude of N-1 harmonics. After each inverter generates the same fundamental wave component according to a given fundamental wave modulation ratio M, each inverter still has (N-1) degrees of freedom to eliminate (N-1) harmonics. In this way, p parallel systems can eliminate p×(N-1) harmonics on the common AC bus, that is, there are p×(N-1) degrees of freedom. In order to eliminate p×(N-1) harmonics and control the fundamental component, p×N equations need to be solved simultaneously to solve p×N angles, and each inverter has N switches in the p×N solutions horn. The overall switching frequency of the system remains unchanged, but the amount of harmonics that can be eliminated increases several times. Taking p=2, N=3 as an example, the equation (3) for solving the switching angle of the two inverters is shown.

$\begin{matrix} \frac{44}{π π} [[cos cos (({α α}_{1111})) - - cos cos (({α α}_{1212})) + + cos cos (({α α}_{1313}))]] = = M m \\ \frac{44}{π π} [[cos cos (({α α}_{21 twenty one})) - - cos cos (({α α}_{22 twenty two})) + + cos cos (({α α}_{23 twenty three}))]] = = M m \\ \frac{44}{55 π π} [\begin{matrix} cos cos ((55 {α α}_{1111})) - - cos cos ((55 {α α}_{1212})) + + cos cos ((55 {α α}_{1313})) \\ + + cos cos ((55 {α α}_{21 twenty one})) - - cos cos ((55 {α α}_{22 twenty two})) + + cos cos ((55 {α α}_{23 twenty three})) \end{matrix}] = = 00 \\ \frac{44}{77 π π} [\begin{matrix} cos cos ((77 {α α}_{1111})) - - cos cos ((77 {α α}_{1212})) + + cos cos ((77 {α α}_{1313})) \\ + + cos cos ((77 {α α}_{21 twenty one})) - - cos cos ((77 {α α}_{22 twenty two})) + + cos cos ((77 {α α}_{23 twenty three})) \end{matrix}] = = 00 \\ \frac{44}{1111 π π} [\begin{matrix} cos cos ((1111 {α α}_{1111})) - - cos cos ((1111 {α α}_{1212})) + + cos cos ((1111 {α α}_{1313})) \\ + + cos cos ((1111 {α α}_{21 twenty one})) - - cos cos ((1111 {α α}_{22 twenty two})) + + cos cos ((1111 {α α}_{23 twenty three})) \end{matrix}] = = 00 \\ \frac{44}{1313 π π} [\begin{matrix} cos cos ((1313 {α α}_{1111})) - - cos cos ((1313 {α α}_{1212})) + + cos cos ((1313 {α α}_{1313})) \\ + + cos cos ((1313 {α α}_{21 twenty one})) - - cos cos ((1313 {α α}_{22 twenty two})) + + cos cos ((1313 {α α}_{23 twenty three})) \end{matrix}] = = 00 \end{matrix} - - - - - - ((33))$

其中α₁₁，α₁₂，α₁₃为逆变器1四分之一周期内的开关角，α₂₁，α₂₂，α₂₃为逆变器2四分之一周期内的开关角，如图2和图4所示。对于特定的调制比M，5、7、11和13次谐波可在输出公共交流母线上消除。Among them, α ₁₁ , α ₁₂ , and α ₁₃ are the switching angles within a quarter cycle of inverter 1, and α ₂₁ , α ₂₂ , and α ₂₃ are the switching angles within a quarter cycle of inverter 2, as shown in Figure 2 and shown in Figure 4. For a specific modulation ratio M, the 5th, 7th, 11th and 13th harmonics can be eliminated on the output common AC bus.

如图4所示的SHEPWM可以控制基波分量并消除正序和负序谐波分量，但零序分量会存在于单台逆变器的相电压中。零序分量主要是输出电压频率的(3+6n)次谐波，n＝0,1,2…。当逆变器共交直流母线直接并联运行时，逆变器之间会存在零序环流通路。第j台逆变器的零序环流定义为式(4)，其中j＝1,2,3,……p。SHEPWM as shown in Figure 4 can control the fundamental wave component and eliminate the positive and negative sequence harmonic components, but the zero sequence component will exist in the phase voltage of a single inverter. The zero-sequence component is mainly the (3+6n) harmonic of the output voltage frequency, n=0,1,2.... When the inverters are directly connected in parallel with the AC and DC bus, there will be a zero-sequence circulating current path between the inverters. The zero-sequence circulating current of the jth inverter is defined as formula (4), where j=1,2,3,...p.

i_0j＝i_aj+i_bj+i_cj(4)i _0j ＝i _aj +i _bj +i _cj (4)

本实用新型提出了适用于SHEPWM调制的多台并联T型三电平逆变器零序环流抑制方法，即切断逆变器之间零序环流的各个频率分量的流通路径。通过切断多台逆变器之间分量较大的低频环流流通路径，达到抑制环流的目的。本实用新型采用两种方法实现抑制环流：The utility model proposes a method for suppressing zero-sequence circulating current of multiple parallel T-type three-level inverters suitable for SHEPWM modulation, that is, cutting off the flow path of each frequency component of the zero-sequence circulating current between the inverters. By cutting off the low-frequency circulation path with a large component between multiple inverters, the purpose of suppressing the circulation is achieved. The utility model adopts two methods to realize the suppression of circulation:

方法一：p台逆变器中，每台逆变器的输出相电压中都要消除3次和9次谐波，这两个分量在零序环流中占有比例较大。以上述p＝2，N＝3为例，在逆变器输出电压中，这两个谐波完全得到消除，故3次和9次谐波也不会在逆变器之间流动，从而达到抑制环流的目的。每台逆变器都要完全消除这两个谐波，故每台逆变器都需要增加两个开关角，即N＝5，同时保持并联系统自由度为4，即其可消除5、7、11、13次谐波。为求解开关角，可列方程(5)(6)。求解该方程即可得到两台逆变器的开关角。Method 1: Among the p inverters, the 3rd and 9th harmonics must be eliminated in the output phase voltage of each inverter, and these two components occupy a large proportion in the zero-sequence circulating current. Taking the above p=2, N=3 as an example, in the output voltage of the inverter, these two harmonics are completely eliminated, so the 3rd and 9th harmonics will not flow between the inverters, thus achieving The purpose of suppressing circulation. Each inverter must completely eliminate these two harmonics, so each inverter needs to increase two switching angles, that is, N=5, while maintaining a parallel system with 4 degrees of freedom, that is, it can eliminate 5, 7 , 11, 13 harmonics. In order to solve the switching angle, equations (5) (6) can be listed. Solving this equation yields the switching angles of the two inverters.

$\begin{matrix} \frac{44}{π π} [[cos cos (({α α}_{j j 11})) - - cos cos (({α α}_{j j 22})) + + cos cos (({α α}_{j j 33})) - - cos cos (({α α}_{j j 44})) + + cos cos (({α α}_{j j 55}))]] = = M m,, j j = = 11,, 22 \\ \frac{44}{n no π π} [\begin{matrix} cos cos (({nα nα}_{1111})) - - cos cos (({nα nα}_{1212})) + + cos cos (({nα nα}_{1313})) - - cos cos (({nα nα}_{1414})) + + cos cos (({nα nα}_{1515})) \\ + + cos cos (({nα nα}_{21 twenty one})) - - cos cos (({nα nα}_{22 twenty two})) + + cos cos (({nα nα}_{23 twenty three})) - - cos cos (({nα nα}_{24 twenty four})) + + cos cos (({nα nα}_{2525})) \end{matrix}] = = 00,, n no = = 55,, 77,, 1111,, 1313 \end{matrix} - - - - - - ((55))$

$\frac{44}{n no π π} [[c c o o s the s (({nα nα}_{j j 11})) - - c c o o s the s (({nα nα}_{j j 22})) + + c c o o s the s (({nα nα}_{j j 33})) - - c c o o s the s (({nx nx}_{j j 44})) + + c c o o s the s (({nα nα}_{j j 55}))]] = = 00,, j j = = 11,, 22;; n no = = 33,, 99 - - - - - - ((66))$

零序环流成分主要是输出电压频率的(3+6n)次谐波，消除的谐波次数越高，零序环流抑制效果越好。如果要消除m个(3+6n)次谐波分量，每台逆变器每四分之一周期就需要增加m个开关角，系统需要整体增加p×m个开关角，求解开关角的方程组中需要增加p×m个未知数和p×m个方程。m越大，零序环流抑制效果就越好。The zero-sequence circulating current component is mainly the (3+6n) harmonic of the output voltage frequency. The higher the harmonic order eliminated, the better the zero-sequence circulating current suppression effect. If m (3+6n) harmonic components are to be eliminated, each inverter needs to increase m switching angles every quarter cycle, and the system needs to increase p×m switching angles as a whole, and solve the switching angle equation The group needs to add p×m unknowns and p×m equations. The larger m is, the better the zero-sequence circulation suppression effect will be.

在MATLAB/simulink2012B中，以图2所示的两台三电平逆变器并联系统拓扑结构对本实用新型提出的控制策略进行仿真研究。仿真中，直流侧电压为200V，输出频率为50Hz，电容C_A、C_B、C_C为14μF。输出滤波电感L₁、L₂为5mH。在M＝1，N＝5时，第一台逆变器的输出线电压和FFT分析如图5(a)、(b)所示；第二台逆变器的输出线电压和FFT分析如图6(a)、(b)所示；公共连接点处线电压V_AB及其FFT分析如图7(a)、(b)。并联系统输出A相电流及其FFT分析见图8(a)、(b)。可见，三电平T型并联系统的输出电压和相电流中均不含较低的5、7、11和13次谐波，取得了比较满意的特定谐波消除效果。In MATLAB/simulink2012B, the control strategy proposed by the utility model is simulated and studied with the topology structure of the parallel system of two three-level inverters shown in Fig. 2 . In the simulation, the DC side voltage is 200V, the output frequency is 50Hz, and the capacitances C _A , C _B , and C _C are 14 μF. The output filter inductors L ₁ and L ₂ are 5mH. When M=1, N=5, the output line voltage and FFT analysis of the first inverter are shown in Fig. 5(a) and (b); the output line voltage and FFT analysis of the second inverter are shown as Figure 6 (a), (b) shown; common connection point line voltage V _AB and its FFT analysis shown in Figure 7 (a), (b). The output A-phase current of the parallel system and its FFT analysis are shown in Fig. 8(a), (b). It can be seen that the output voltage and phase current of the three-level T-type parallel system do not contain the lower harmonics of the 5th, 7th, 11th and 13th orders, and a satisfactory specific harmonic elimination effect has been achieved.

图9(a)为并联逆变器没有抑制环流的仿真结果，图9(b)为并联逆变器采用本实用新型的环流抑制方法后的仿真结果。可见，没有抑制环流时零序环流幅值约14A，将会严重影响系统运行的稳定性；环流抑制后零序环流幅值约为1.4A，幅值缩小为抑制前的1/10。说明本实用新型的环流抑制方法能够有效抑制SHEPWM调制的多台T型三电平逆变器并联系统的零序环流。Fig. 9(a) is the simulation result of the parallel inverter without suppressing the circulating current, and Fig. 9(b) is the simulation result of the parallel inverter adopting the circulating current suppressing method of the utility model. It can be seen that the zero-sequence circulating current amplitude is about 14A when the circulating current is not suppressed, which will seriously affect the stability of the system operation; after the circulating current is suppressed, the zero-sequence circulating current amplitude is about 1.4A, and the amplitude is reduced to 1/10 of that before suppression. It shows that the circulating current suppression method of the utility model can effectively suppress the zero-sequence circulating current of the parallel system of multiple T-type three-level inverters modulated by SHEPWM.

对于p台逆变器，根据方法一，系统根据公式(7)和(8)即可算出开关角度。For p inverters, according to method one, the system can calculate the switching angle according to formulas (7) and (8).

$\begin{matrix} \frac{44}{π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} {cosα cosα}_{j j k k})) = = M m,, j j = = 11,, 22,, ... ... p p \\ \frac{44}{n no π π} (({Σ Σ}_{j j = = 11}^{p p} [[{Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} cos cos (({nα nα}_{j j k k}))]])) = = 00,, n no = = 55,, 77,, ... ... \end{matrix} - - - - - - ((77))$

$\frac{44}{n no π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} c c o o s the s (({nα nα}_{j j k k})))) = = 00,, n no = = 33,, 99;; j j = = 11,, 22,, ... ...,, p p - - - - - - ((88))$

方法二：在p台逆变器中，其中前p-1台逆变器的输出相电压中都要消除3次和9次谐波，这两个分量在零序环流中占有比例较大，由于p-1台逆变器的输出相电压中都要消除3次和9次谐波，所以第p台逆变器就消除了3次和9次谐波回路，第p台逆变器也不会含有3次和9次谐波，达到抑制环流的目的。前p-1台逆变器都要完全消除这两个谐波，故每台逆变器都需要增加两个开关角，而第p台逆变器不用消除3次和9次谐波，所以系统多了两个自由度，就可以多消除两个谐波。以上述p＝2，N＝3为例，在逆变器输出电压中，由于在一台逆变器中这两个谐波完全得到消除，从而对于另外一台逆变器来说消除了3次和9次谐波回路，故3次和9次谐波也不会在逆变器之间流动，从而达到抑制环流的目的。第一台逆变器都要完全消除这两个谐波，故第一台逆变器都需要增加两个开关角，为了使两台逆变器开关频率相同，使N＝5，即并联系统增加了两个自由度，增加为6，即其可消除5、7、11、13、17、19次谐波。为求解开关角，可列方程(9)(10)。求解该方程即可得到两台逆变器的开关角。Method 2: Among the p inverters, the 3rd and 9th harmonics must be eliminated in the output phase voltage of the first p-1 inverters. These two components occupy a large proportion in the zero-sequence circulating current. Since the 3rd and 9th harmonics must be eliminated in the output phase voltage of p-1 inverters, the pth inverter eliminates the 3rd and 9th harmonic loops, and the pth inverter also It will not contain the 3rd and 9th harmonics to achieve the purpose of suppressing the circulation. The first p-1 inverters must completely eliminate these two harmonics, so each inverter needs to increase two switching angles, and the pth inverter does not need to eliminate the 3rd and 9th harmonics, so With two more degrees of freedom in the system, two more harmonics can be eliminated. Taking the above p=2, N=3 as an example, in the output voltage of the inverter, since these two harmonics are completely eliminated in one inverter, 3 harmonics are eliminated for the other inverter. The 3rd and 9th harmonic loops, so the 3rd and 9th harmonics will not flow between the inverters, so as to achieve the purpose of suppressing the circulation. The first inverter must completely eliminate these two harmonics, so the first inverter needs to increase two switching angles. In order to make the switching frequency of the two inverters the same, make N=5, that is, a parallel system Two degrees of freedom are added, and the increase is 6, that is, it can eliminate the 5th, 7th, 11th, 13th, 17th, and 19th harmonics. In order to solve the switching angle, equations (9) (10) can be listed. Solving this equation yields the switching angles of the two inverters.

$\begin{matrix} \frac{44}{π π} [[cos cos (({α α}_{j j 11})) - - cos cos (({α α}_{j j 22})) + + cos cos (({α α}_{j j 33})) - - cos cos (({α α}_{j j 44})) + + cos cos (({α α}_{j j 55}))]] = = M m,, j j = = 11,, 22 \\ \frac{44}{n no π π} [\begin{matrix} cos cos (({nα nα}_{1111})) - - cos cos (({nα nα}_{1212})) + + cos cos (({nα nα}_{1313})) - - cos cos (({nα nα}_{1414})) + + cos cos (({nα nα}_{1515})) \\ + + cos cos (({nα nα}_{21 twenty one})) - - cos cos (({nα nα}_{22 twenty two})) + + cos cos (({nα nα}_{23 twenty three})) - - cos cos (({nα nα}_{24 twenty four})) + + cos cos (({nα nα}_{2525})) \end{matrix}] = = 00,, n no = = 55,, 77,, 1111,, 1313,, 1717,, 1919 \end{matrix} - - - - - - ((99))$

$\frac{44}{n no π π} [[c c o o s the s (({nα nα}_{1111})) - - c c o o s the s (({nα nα}_{1212})) + + c c o o s the s (({nα nα}_{1313})) - - c c o o s the s (({nα nα}_{1414})) + + c c o o s the s (({nα nα}_{1515}))]] = = 00,, n no = = 33,, 99 - - - - - - ((1010))$

零序环流成分主要是输出电压频率的(3+6n)次谐波，消除的谐波次数越高，零序环流抑制效果越好。如果要消除m个(3+6n)次谐波分量，每台逆变器每四分之一周期就需要增加m个开关角，其中p-1台逆变器利用增加的m个开关角切断零序环流的m个低频分量，剩余1台逆变器利用增加的m个开关角进一步消除m个谐波。系统需要整体增加p×m个开关角，求解开关角的方程组中需要增加p×m个未知数和p×m个方程。m越大，零序环流抑制效果就越好，同时公共交流母线上谐波消除效果越好。相比方法一，在开关角数量相同的情况下，方法二可以在公共交流母线上消除更多谐波。The zero-sequence circulating current component is mainly the (3+6n) harmonic of the output voltage frequency. The higher the harmonic order eliminated, the better the zero-sequence circulating current suppression effect. If it is necessary to eliminate m (3+6n) harmonic components, each inverter needs to increase m switching angles every quarter cycle, and p-1 inverters use the increased m switching angles to cut off For the m low-frequency components of the zero-sequence circulating current, the remaining one inverter further eliminates the m harmonics by using the increased m switching angles. The system needs to add p×m switching angles as a whole, and p×m unknowns and p×m equations need to be added to the equation system for solving the switching angles. The larger m is, the better the zero-sequence circulation suppression effect is, and the better the harmonic elimination effect is on the public AC bus. Compared with method 1, method 2 can eliminate more harmonics on the common AC bus with the same number of switching angles.

在MATLAB/simulink2012B中，以图2所示的两台三电平逆变器并联系统拓扑结构对本实用新型提出的控制策略进行仿真研究。仿真中，直流侧电压为200V，输出频率为50Hz，电容C_A、C_B、C_C为14μF。输出滤波电感L₁、L₂为5mH。在M＝1，N＝5时，第一台逆变器的输出线电压和FFT分析如图10(a)、(b)所示；第二台逆变器的输出线电压和FFT分析如图11(a)、(b)所示；公共连接点处线电压V_AB及其FFT分析如图12(a)、(b)。并联系统输出A相电流及其FFT分析见图13(a)、(b)。可见，三电平T型并联系统的输出电压和相电流中均不含较低的5、7、11、13、17和19次谐波，取得了比较满意的特定谐波消除效果。In MATLAB/simulink2012B, the control strategy proposed by the utility model is simulated and studied with the topology structure of the parallel system of two three-level inverters shown in Fig. 2 . In the simulation, the DC side voltage is 200V, the output frequency is 50Hz, and the capacitances C _A , C _B , and C _C are 14 μF. The output filter inductors L ₁ and L ₂ are 5mH. When M=1, N=5, the output line voltage and FFT analysis of the first inverter are shown in Figure 10(a) and (b); the output line voltage and FFT analysis of the second inverter are as follows Figure 11 (a), (b) shown; the line voltage V _AB at the common connection point and its FFT analysis are shown in Figure 12 (a), (b). The output A-phase current of the parallel system and its FFT analysis are shown in Fig. 13(a), (b). It can be seen that the output voltage and phase current of the three-level T-type parallel system do not contain the lower 5th, 7th, 11th, 13th, 17th and 19th harmonics, and a satisfactory specific harmonic elimination effect has been achieved.

图14(a)为并联逆变器没有抑制环流的仿真结果，图14(b)为并联逆变器采用本实用新型的环流抑制方法后的仿真结果。可见，没有抑制环流时零序环流幅值约14A，将会严重影响系统运行的稳定性；环流抑制后零序环流幅值约为2.1A，幅值缩小为抑制前的将近1/7。说明本实用新型的环流抑制方法能够有效抑制SHEPWM调制的多台T型三电平逆变器并联系统的零序环流。Fig. 14(a) is the simulation result of the parallel inverter without suppressing the circulating current, and Fig. 14(b) is the simulation result of the parallel inverter adopting the circulating current suppressing method of the utility model. It can be seen that the zero-sequence circulating current amplitude is about 14A when the circulating current is not suppressed, which will seriously affect the stability of the system operation; after the circulating current is suppressed, the zero-sequence circulating current amplitude is about 2.1A, and the amplitude is reduced to nearly 1/7 of that before suppression. It shows that the circulating current suppression method of the utility model can effectively suppress the zero-sequence circulating current of the parallel system of multiple T-type three-level inverters modulated by SHEPWM.

对于p台逆变器，根据方法二，系统根据公式(11)和(12)即可算出开关角度。For p inverters, according to the second method, the system can calculate the switching angle according to formulas (11) and (12).

$\begin{matrix} \frac{44}{π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} {cosα cosα}_{j j k k})) = = M m,, j j = = 11,, 22,, ... ...,, p p \\ \frac{44}{n no π π} (({Σ Σ}_{j j = = 11}^{p p} [[{Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} cos cos (({nα nα}_{j j k k}))]])) = = 00,, n no = = 55,, 77,, ... ... \end{matrix} - - - - - - ((1111))$

$\frac{44}{n no π π} (({Σ Σ}_{k k = = 11}^{N N} {((- - 11))}^{k k + + 11} c c o o s the s (({nα nα}_{j j k k})))) = = 00,, n no = = 33,, 99;; j j = = 11,, 22,, ... ...,, p p - - 11 - - - - - - ((1212))$

通过以上仿真结果可知，相比于方法二，方法一能实现逆变器之间环流更小，但消除的谐波比方法二少两个，所以采用方法一时系统输出电流不如方法二。方法二改善输出波形的代价是零序环流会略有增加，这是因为开关角并不能够精确的将3次、9次等低次谐波完全消除。零序环流增加的量相对于系统输出来说非常小，几乎可以忽略，对系统稳定性没有影响。但与此同时，交流母线上消除了更多的谐波，提高了输出波形质量。因此方法二比方法一实用意义更大。方法一和方法二都对环流进行了有效的抑制，效果明显，且消除的谐波个数比普通的SHEPWM更多，系统输出波形效果更好。本实用新型采用SHEPWM的多台T型三电平逆变器并联系统能保持SHEPWM消除特定谐波的能力，在每四分之一周期开关角相同的情况下，并联系统可以消除更多的谐波。本实用新型中多台逆变器之间的环流也得到有效抑制。From the above simulation results, it can be seen that compared with method 2, method 1 can achieve smaller circulating current between inverters, but eliminates two less harmonics than method 2, so the system output current is not as good as method 2 when method 1 is adopted. The cost of method 2 to improve the output waveform is that the zero-sequence circulating current will increase slightly, because the switching angle cannot completely eliminate the 3rd, 9th and other low-order harmonics. The increase of the zero-sequence circulating current is very small relative to the system output, almost negligible, and has no effect on the system stability. But at the same time, more harmonics are eliminated on the AC bus, which improves the output waveform quality. Therefore, Method 2 is more practical than Method 1. Both method 1 and method 2 have effectively suppressed the circulating current, the effect is obvious, and the number of harmonics eliminated is more than that of ordinary SHEPWM, and the system output waveform effect is better. The utility model adopts the multiple T-type three-level inverter parallel system of SHEPWM, which can maintain the ability of SHEPWM to eliminate specific harmonics. In the case of the same switching angle every quarter cycle, the parallel system can eliminate more harmonics. Wave. The circulating current between multiple inverters in the utility model is also effectively suppressed.

本方法易于实现，不需要对逆变器的硬件和软件进行大量改动，只需要改变预存的SHEPWM开关角数组表，或在实际产品中设计多种查表备选方案，通过人为的模式切换，以适应单台或多台运行的环境，具有简单易行和便于模块化扩展的优点。This method is easy to implement, does not need to make a lot of changes to the hardware and software of the inverter, only needs to change the pre-stored SHEPWM switch angle array table, or design a variety of look-up table alternatives in the actual product, through artificial mode switching, To adapt to the single or multiple operating environment, it has the advantages of simple operation and easy modular expansion.

上述虽然结合附图对本实用新型的具体实施方式进行了描述，但并非对本实用新型保护范围的限制，所属领域技术人员应该明白，在本实用新型的技术方案的基础上，本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本实用新型的保护范围以内。Although the specific implementation of the utility model has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the utility model. Those skilled in the art should understand that on the basis of the technical solution of the utility model, those skilled in the art do not need to Various modifications or deformations that can be made with creative efforts are still within the protection scope of the present utility model.

Claims

1. the zero sequence loop current suppression system of the T-shaped three-level inverter of multiple stage of a SHEPWM modulation, it is characterized in that: include pulse signal generator, controller, switching angle controller and T-shaped three-level inverter parallel system, wherein, T-shaped three-level inverter parallel system, T-shaped three-level inverter including multiple parallel connections, all T-shaped three-level inverters share alternating current-direct current bus, and the midpoint of all T-shaped three-level inverter DC side split capacitors is connected, it is connected in parallel after the AC device after filtering filtering of all T-shaped three-level inverters；

Described pulse signal generator produces pulse signal, it is sent to each T-shaped three-level inverter, described controller controls cut-offfing of the switching device of T-shaped three-level inverter parallel system by SHEPWM modulation system, described switching angle controller controls the switching angle of each T-shaped three-level inverter, cuts off each frequency component path of zero sequence circulation.

The zero sequence loop current suppression system of the T-shaped three-level inverter of multiple stage of a kind of SHEPWM the most as claimed in claim 1 modulation, it is characterized in that: described T-shaped three-level inverter, including three-phase brachium pontis in parallel, every phase brachium pontis includes two IGBT pipes connected, the IGBT that side, the midpoint series connection both direction of each phase brachium pontis is different manages, and the filtered device of opposite side is connected with load or electrical network；Input voltage source is accessed at each brachium pontis input in parallel；Every inverter input direct-current side is parallel with two groups of electric capacity, and one end of the both direction difference IGBT pipe of two groups of each phase brachium pontis of electric capacity junction connection, each IGBT pipe is driven by control signal.

The zero sequence loop current suppression system of the T-shaped three-level inverter of multiple stage of a kind of SHEPWM the most as claimed in claim 2 modulation, is characterized in that: described controller is decoupling controller, drives each IGBT of T-shaped three-level inverter to manage.

The zero sequence loop current suppression system of the T-shaped three-level inverter of multiple stage of a kind of SHEPWM the most as claimed in claim 1 modulation, is characterized in that: described T-shaped three-level inverter parallel system uses different switching angles.

The zero sequence loop current suppression system of the T-shaped three-level inverter of multiple stage of a kind of SHEPWM the most as claimed in claim 1 modulation, is characterized in that: described wave filter is inductance.