技术领域technical field
本发明属于电力电子技术领域，具体涉及一种基于MMC的固态变压器以及控制方法。The invention belongs to the technical field of power electronics, and in particular relates to an MMC-based solid-state transformer and a control method.
背景技术Background technique
固态变压器又称为电力电子变压器或柔性变压器，它是以电力电子变流技术和电磁感应技术为基础的新型变压器，它彻底的改变了传统变压器的系统结构，在实现常规电力变压器电压等级变换、电气隔离和能量传递等基本功能的基础上，还可以实现双向潮流控制、电能质量控制等许多额外功能，是下一代智能电网建设的关键装备。受电力电子元器件发展水平的限制，适应于电网需求的高压、大功率、大电流的满足四象限运行的固态变压器必须采用全控型电力电子器件串、并联或多电平的方式。目前常用的适合于高压大功率场合的固态变压器主电路拓扑主要是基于H桥级联型(如图1)、中点箝位型多电平换流器的固态变压器，这些拓扑结构具有诸多优点，但是也存在着不易模块化构建、控制复杂、所需器件过多等缺点，此类拓扑结构的固态变压器不具备自动抑制电网与负荷间的相互电能质量干扰功能。Solid-state transformer is also called power electronic transformer or flexible transformer. It is a new type of transformer based on power electronic conversion technology and electromagnetic induction technology. It completely changes the system structure of traditional transformers. On the basis of basic functions such as electrical isolation and energy transfer, it can also realize many additional functions such as bidirectional power flow control and power quality control. It is the key equipment for the construction of the next generation of smart grid. Restricted by the development level of power electronic components, solid-state transformers that meet the requirements of the power grid for high voltage, high power, and high current that meet four-quadrant operation must use fully controlled power electronic devices in series, parallel or multi-level mode. At present, the main circuit topology of the solid-state transformer suitable for high-voltage and high-power occasions is mainly based on the H-bridge cascaded type (as shown in Figure 1), and the solid-state transformer of the mid-point clamped multi-level converter. These topological structures have many advantages. , but there are also disadvantages such as difficult modular construction, complex control, and too many components required. The solid-state transformer of this topology does not have the function of automatically suppressing the mutual power quality interference between the grid and the load.
发明内容Contents of the invention
为了克服上述现有技术的不足，本发明提供一种基于MMC的固态变压器以及控制方法，基于MMC结构的互平衡固态变压器可以通过控制高压级公共直流母线电压的恒定，实现抑制三相不平衡负荷对电网的影响，以及电网出现三相不对称对交流负荷的影响。In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a solid-state transformer based on MMC and a control method. The mutual-balanced solid-state transformer based on the MMC structure can realize the suppression of three-phase unbalanced load by controlling the constant voltage of the high-voltage public DC bus. The impact on the power grid, and the impact of the three-phase asymmetry of the power grid on the AC load.
为了实现上述发明目的，本发明采取如下技术方案：In order to realize the above-mentioned purpose of the invention, the present invention takes the following technical solutions:
本发明提供一种基于MMC的固态变压器，所述固态变压器包括高压级AC/DC变换器、隔离级DC/DC变换器和低压级DC/AC变换器；所述高压级AC/DC变换器通过高压直流母线连接隔离级DC/DC变换器，所述隔离级DC/DC变换器通过低压级直流母线并联模块连接低压级DC/AC变换器。The invention provides a solid-state transformer based on MMC, the solid-state transformer includes a high-voltage AC/DC converter, an isolation-level DC/DC converter and a low-voltage DC/AC converter; the high-voltage AC/DC converter passes The high-voltage DC bus is connected to the isolation-level DC/DC converter, and the isolation-level DC/DC converter is connected to the low-voltage DC/AC converter through the low-voltage DC bus parallel module.
所述高压级AC/DC变换器采用MMC，以提高固态变压器输入级的电压等级；The high-voltage AC/DC converter adopts MMC to improve the voltage level of the input stage of the solid-state transformer;
所述高压级AC/DC换流器每个相单元投入的子模块数为2M，上桥臂和下桥臂串联子模块数均为M，且每个子模块均与隔离级高压侧DC/AC变换模块的单相全桥DC/AC变换器通过共用直流电容的方式连接，完成高压直流电压到高频交流方波的变换。The number of sub-modules invested in each phase unit of the high-voltage AC/DC converter is 2M, and the number of sub-modules connected in series on the upper bridge arm and the lower bridge arm is M, and each sub-module is connected to the isolation stage high-voltage side DC/AC The single-phase full-bridge DC/AC converter of the conversion module is connected by sharing a DC capacitor to complete the conversion of high-voltage DC voltage to high-frequency AC square wave.
所述隔离级DC/DC变换器包括隔离级高压侧DC/AC变换模块、隔离级高频变压器和隔离级低压侧AC/DC变换模块；The isolation-level DC/DC converter includes an isolation-level high-voltage side DC/AC conversion module, an isolation-level high-frequency transformer, and an isolation-level low-voltage side AC/DC conversion module;
所述隔离级高频变压器的原边绕组与副边绕组之间变比为2M：3，隔离级低压输出侧AC/DC变换模块的单相全桥AC/DC模块连接低压级直流母线并联模块，完成高频交流方波到低压直流电压的变换。The transformation ratio between the primary winding and the secondary winding of the isolation stage high-frequency transformer is 2M:3, and the single-phase full-bridge AC/DC module of the AC/DC conversion module on the low-voltage output side of the isolation stage is connected to the low-voltage stage DC bus parallel module , to complete the conversion of high-frequency AC square wave to low-voltage DC voltage.
所述低压级DC/AC变换器由低压级直流母线并联模块和三个独立控制的单相全桥逆变器以及对应LC滤波器组成，输出所需要的交流电能，实现固态变压器的电压变换、电能传输和电能质量控制。The low-voltage level DC/AC converter is composed of a low-voltage level DC bus parallel module, three independently controlled single-phase full-bridge inverters and corresponding LC filters, and outputs the required AC power to realize the voltage conversion of the solid-state transformer, Power transmission and power quality control.
本发明还提供一种基于MMC的固态变压器的控制方法，所述控制方法包括以下步骤：The present invention also provides a kind of control method based on MMC solid-state transformer, and described control method comprises the following steps:
步骤1：高压级AC/DC变换器进行电压和电流的双闭环控制、环流抑制控制和子模块电容电压均衡控制；Step 1: The high-voltage AC/DC converter performs double closed-loop control of voltage and current, circulation suppression control and sub-module capacitor voltage equalization control;
步骤2：隔离级DC/DC变换器进行高压级AC/DC变换器与低压级DC/AC变换器之间的电气隔离以及电压等级变换控制；Step 2: The isolation level DC/DC converter performs electrical isolation between the high-voltage level AC/DC converter and the low-voltage level DC/AC converter and voltage level conversion control;
步骤3：低压级DC/AC变换器进行相电压有效值恒定控制并实现波形正弦化。Step 3: The low-voltage stage DC/AC converter performs constant control of the effective value of the phase voltage and realizes sinusoidal waveform.
所述步骤1中，高压级AC/DC变换器采用定有功功率矢量控制方法在dq坐标系下进行电压和电流的双闭环控制、环流抑制控制和子模块电容电压均衡控制。In the step 1, the high-voltage AC/DC converter adopts the constant active power vector control method to perform double closed-loop control of voltage and current, circulation suppression control and sub-module capacitor voltage equalization control in the dq coordinate system.
所述步骤2中，隔离级DC/DC变换器采用开环控制策略进行高压级AC/DC变换器与低压级DC/AC变换器之间的电气隔离以及电压等级变换控制。In the step 2, the isolation-level DC/DC converter adopts an open-loop control strategy to perform electrical isolation between the high-voltage level AC/DC converter and the low-voltage level DC/AC converter and voltage level conversion control.
所述步骤2包括以下步骤：Described step 2 comprises the following steps:
步骤2-1：高压级AC/DC变换器输出的高压直流电压经隔离级高压侧DC/AC变换模块调制成高频交流方波；Step 2-1: The high-voltage DC voltage output by the high-voltage stage AC/DC converter is modulated into a high-frequency AC square wave by the DC/AC conversion module on the high-voltage side of the isolation stage;
步骤2-2：高频交流方波经隔离级高频变压器同步耦合至隔离级低压侧AC/DC变换模块；Step 2-2: The high-frequency AC square wave is synchronously coupled to the AC/DC conversion module on the low-voltage side of the isolation stage through the isolation-level high-frequency transformer;
步骤2-3：耦合至隔离级低压侧AC/DC变换模块的高频交流方波经隔离级低压侧AC/DC变换模块同步整流为低压直流电压，输出给低压级DC/AC变换器。Step 2-3: The high-frequency AC square wave coupled to the AC/DC conversion module on the low-voltage side of the isolation stage is synchronously rectified into a low-voltage DC voltage by the AC/DC conversion module on the low-voltage side of the isolation stage, and output to the low-voltage DC/AC converter.
所述步骤3中，低压级DC/AC变换器采用双环控制策略进行相电压有效值恒定控制，并实现波形正弦化。In the step 3, the low-voltage stage DC/AC converter adopts a double-loop control strategy to control the effective value of the phase voltage constant, and realizes sinusoidal waveform.
所述步骤3包括以下步骤：Described step 3 comprises the following steps:
步骤3-1：在外环控制策略中，先通过相电压瞬时值得到实际相电压有效值，然后将相电压有效值与相电压指令值进行比较，得到的偏差经过PI控制器后与标准正弦信号相乘，作为内环控制策略中相电压瞬时值的指令值；Step 3-1: In the outer loop control strategy, the actual effective value of the phase voltage is first obtained through the instantaneous value of the phase voltage, and then the effective value of the phase voltage is compared with the command value of the phase voltage, and the obtained deviation is compared with the standard sinusoidal value after passing through the PI controller The signals are multiplied and used as the command value of the instantaneous value of the phase voltage in the inner loop control strategy;
步骤3-2：在内环控制策略中，先将外环控制策略中输出的相电压瞬时值的指令值与反馈的实际相电压瞬时值相比较，然后将其误差量经比例控制器后作为调制波指令信号，最后并将该调制波指令信号与三角载波信号比较，形成脉冲触发信号以触发功率开关器件正确动作。Step 3-2: In the inner loop control strategy, first compare the command value of the instantaneous value of the phase voltage output in the outer loop control strategy with the actual feedback instantaneous value of the phase voltage, and then pass the error amount through the proportional controller as The modulated wave command signal is finally compared with the triangular carrier signal to form a pulse trigger signal to trigger the correct action of the power switching device.
与现有技术相比，本发明的有益效果在于：Compared with prior art, the beneficial effect of the present invention is:
1)MMC电路具有高度模块化，灵活调整投入换流器的子模块个数就可以满足不同功率和不同电压等级的要求，相比其他多电平换流器，在硬件拓扑上具有明显的优势；1) The MMC circuit has a high degree of modularity, and the flexible adjustment of the number of sub-modules put into the converter can meet the requirements of different power and different voltage levels. Compared with other multi-level converters, it has obvious advantages in hardware topology ;
2)与传统VSC的拓扑不同，MMC每个桥臂中都串有桥臂电抗器，桥臂电抗器能够抑制由各并联相单元的直流电压瞬时值不完全相同而造成的相间环流，同时还能够有效减小直流母线发生故障时故障电流的上升率，抑制冲击电流，提高系统的可靠性；2) Different from the topology of the traditional VSC, each bridge arm of the MMC has a bridge arm reactor in series. The bridge arm reactor can suppress the phase-to-phase circulation caused by the instantaneous value of the DC voltage of each parallel phase unit. It can effectively reduce the rising rate of the fault current when the DC bus fails, suppress the inrush current, and improve the reliability of the system;
3)低压级直流侧通过采用直流母线交错并联这种拓扑结构，从而在结构上解决了固态变压器高、低压侧系统不平衡的相互影响，自动提高了供电可靠性‘3) The DC side of the low-voltage level adopts the topology structure of interleaving and paralleling the DC bus, thus structurally solving the mutual influence of the unbalanced system of the high-voltage and low-voltage side of the solid-state transformer, and automatically improving the reliability of power supply'
4)基于MMC结构的互平衡固态变压器可以通过控制高压级公共直流母线电压的恒定，实现抑制三相不平衡负荷对电网的影响，以及电网出现三相不对称对交流负荷的影响。4) The mutual balanced solid-state transformer based on the MMC structure can control the constant voltage of the high-voltage public DC bus to suppress the impact of the three-phase unbalanced load on the power grid, and the impact of the three-phase asymmetry of the power grid on the AC load.
附图说明Description of drawings
图1是现有技术中基于H桥级联型固态变压器主电路拓扑结构图；Fig. 1 is the topological structure diagram of the main circuit based on H-bridge cascaded solid-state transformer in the prior art;
图2是本发明实施例中基于MMC的固态变压器主电路拓扑结构图；Fig. 2 is the topological structure diagram of the solid-state transformer main circuit based on MMC in the embodiment of the present invention;
图3是本发明实施例中低压级直流母线接线图；Fig. 3 is a wiring diagram of a low-voltage level DC bus in the embodiment of the present invention;
图4是本发明实施例中MMC主电路拓扑结构图；Fig. 4 is MMC main circuit topological structure figure in the embodiment of the present invention;
图5是本发明实施例中MMC中子模块拓扑结构图；Fig. 5 is the topological structure diagram of MMC neutron module in the embodiment of the present invention;
图6是本发明实施例中高压级AC/DC变换器控制策略图；Fig. 6 is a control strategy diagram of a high-voltage stage AC/DC converter in an embodiment of the present invention;
图7是本发明实施例中电容电压均衡控制框图；7 is a block diagram of capacitor voltage equalization control in an embodiment of the present invention;
图8是本发明实施例中隔离级DC/DC变换器控制框图；FIG. 8 is a control block diagram of an isolation-level DC/DC converter in an embodiment of the present invention;
图9是本发明实施例中低压级DC/AC变换器控制策图。Fig. 9 is a control strategy diagram of the low-voltage stage DC/AC converter in the embodiment of the present invention.
具体实施方式detailed description
下面结合附图对本发明作进一步详细说明。The present invention will be described in further detail below in conjunction with the accompanying drawings.
本发明针对目前固态变压器无法适应高压大功率配电系统，以及不能抑制电网出现三相交流不对称与三相负载不平衡时输入和输出端间的相互影响等问题，提出了一种基于MMC变换器的固态变压器，可以通过调节MMC变换器高压公共直流母线电压的恒定，来抑制三相不平衡负荷对电网的影响，以及电网出现三相不对称对交流负荷的影响，并且，MMC换流器拓扑结构具有高度模块化，通过灵活调整投入的串联子模块个数就可以满足不同功率和不同电压等级场合的需求。以及可以通过调节高压公共直流母线电压的恒定和低压级直流侧采用直流母线交错并联这种拓扑结构，从而使固态变压器即使在电网出现三相交流不对称或是三相不平衡负荷情况下也能实现稳定运行。Aiming at the problems that the current solid-state transformer cannot adapt to the high-voltage and high-power power distribution system, and cannot suppress the mutual influence between the input and output terminals when the three-phase AC asymmetry occurs in the power grid and the three-phase load is unbalanced, the present invention proposes an MMC-based transformation The solid-state transformer of the inverter can suppress the influence of the three-phase unbalanced load on the power grid by adjusting the constant voltage of the high-voltage public DC bus of the MMC converter, and the influence of the three-phase asymmetry of the power grid on the AC load, and the MMC converter The topology is highly modular, and the requirements of different power and voltage levels can be met by flexibly adjusting the number of sub-modules connected in series. And the topology structure of the DC bus can be interleaved and paralleled by adjusting the constant and low-voltage DC side of the high-voltage public DC bus voltage, so that the solid-state transformer can be used even in the case of three-phase AC asymmetry or three-phase unbalanced load in the power grid. achieve stable operation.
本发明提供的一种基于模块化多电平换流器(MMC)的固态变压器以及控制方法，该固态变压器的高压级AC/DC变换器采用MMC换流器来提高固态变压器输入级的电压等级，低压级直流侧通过直流母线并联模块来实现固态变压器的自动互平衡功能。本专利设计的基于MMC换流器的固态变压器可以通过调节高压公共直流母线电压的恒定，来实现抑制三相不平衡负荷对电网的影响，以及电网出现三相不对称对交流负荷的影响，并且，MMC换流器拓扑结构具有高度模块化，通过灵活调整投入的串联子模块个数就可以满足不同功率和不同电压等级场合的需求，相比与其他多电平换流器，在硬件拓扑上具有明显的优势。另外，低压级直流侧采用直流母线交错并联这种拓扑结构，从而在结构上解决了固态变压器高、低压侧系统不平衡的相互影响，自动提高了供电可靠性，只要一个子模块运行正常就能保证基本用电，而且其结构简单、控制方便，这也是本发明设计的固态变压器能够实现自动互平衡功能的关键所在。固态变压器是一种将电力电子变换技术和基于电磁感应原理的电能交换技术相结合，实现将一种电力特征的电能转变为另一种电力特征的电力设备。在结构上，它包含两个基本要素：电力电子变换器和高频变压器，其中电力电子变换器包含主电路部分和控制电路部分；高频变压器实现两侧电力电子变换器的链接，其主要功能是实现电气隔离和电压等级变换，频率通常工作在千赫兹(kHz)级别，高频化的目的主要是大幅缩小变压器的体积、减轻重量、减少散热以及提高变压器容量与效率等。The present invention provides a solid-state transformer based on a modular multilevel converter (MMC) and a control method. The high-voltage AC/DC converter of the solid-state transformer adopts the MMC converter to increase the voltage level of the input stage of the solid-state transformer , the low-voltage level DC side realizes the automatic mutual balance function of the solid-state transformer through the DC bus parallel module. The solid-state transformer based on the MMC converter designed in this patent can suppress the impact of three-phase unbalanced loads on the power grid and the impact of three-phase asymmetry on the AC load by adjusting the constant high-voltage public DC bus voltage, and , the MMC converter topology is highly modular, by flexibly adjusting the number of sub-modules in series to meet the needs of different power and voltage levels, compared with other multi-level converters, in terms of hardware topology has obvious advantages. In addition, the DC side of the low-voltage stage adopts the DC bus interleaved parallel topology, which structurally solves the mutual influence of the high-voltage and low-voltage side systems of the solid-state transformer, and automatically improves the reliability of the power supply. As long as one sub-module operates normally, it can Guarantee basic electricity consumption, and its structure is simple, convenient to control, and this is also the key point that the solid-state transformer designed by the present invention can realize the function of automatic mutual balance. A solid-state transformer is a power device that combines power electronic conversion technology with power exchange technology based on the principle of electromagnetic induction to convert electrical energy of one power characteristic into another power characteristic. Structurally, it contains two basic elements: a power electronic converter and a high-frequency transformer. The power electronic converter includes the main circuit part and the control circuit part; the high-frequency transformer realizes the link between the power electronic converters on both sides, and its main function is It is to achieve electrical isolation and voltage level conversion. The frequency usually works at the kilohertz (kHz) level. The purpose of high frequency is to greatly reduce the size of the transformer, reduce weight, reduce heat dissipation, and improve transformer capacity and efficiency.
本发明提供一种基于MMC的固态变压器，如图2，所述固态变压器包括高压级AC/DC变换器、隔离级DC/DC变换器和低压级DC/AC变换器；所述高压级AC/DC变换器通过高压直流母线连接隔离级DC/DC变换器，所述隔离级DC/DC变换器通过低压级直流母线并联模块连接低压级DC/AC变换器。The present invention provides a solid-state transformer based on MMC, as shown in Figure 2, the solid-state transformer includes a high-voltage stage AC/DC converter, an isolation stage DC/DC converter and a low-voltage stage DC/AC converter; the high-voltage stage AC/DC converter The DC converter is connected to the isolation-level DC/DC converter through the high-voltage DC bus, and the isolation-level DC/DC converter is connected to the low-voltage DC/AC converter through the low-voltage DC bus parallel module.
所述高压级AC/DC变换器采用MMC，以提高固态变压器输入级的电压等级；The high-voltage AC/DC converter adopts MMC to improve the voltage level of the input stage of the solid-state transformer;
所述高压级AC/DC换流器每个相单元投入的子模块数为2M，上桥臂和下桥臂串联子模块数均为M，且每个子模块均与隔离级高压侧DC/AC变换模块的单相全桥DC/AC变换器通过共用直流电容的方式连接，完成高压直流电压到高频交流方波的变换。The number of sub-modules invested in each phase unit of the high-voltage AC/DC converter is 2M, and the number of sub-modules connected in series on the upper bridge arm and the lower bridge arm is M, and each sub-module is connected to the isolation stage high-voltage side DC/AC The single-phase full-bridge DC/AC converter of the conversion module is connected by sharing a DC capacitor to complete the conversion of high-voltage DC voltage to high-frequency AC square wave.
低压级直流母线并联模块接线图如附图3所示，隔离级低压侧3个单相全桥变流器模块的直流输出DCAi、DCBi、DCCi(i＝1，2，3)对应地并联在一起，组成固态变压器低压级3个单相全桥逆变模块的直流母线DCa、DCb、DCc。这种低压侧直流母线交错并联的最大优点是从结构上解决了固态变压器高、低压侧系统不平衡的相互影响，而且自动提高了供电可靠性，只要一个子模块运行正常就能保证基本用电，而且其结构简单、控制方便，这也是本专利设计的固态变压器能够实现自动互平衡功能的关键所在。The wiring diagram of the low-voltage level DC bus parallel module is shown in Figure 3. The DC outputs DCAi , DCBi , and DCCi (i=1, 2, 3) of the three single-phase full-bridge converter modules on the low-voltage side of the isolation stage correspond to The ground and ground are connected in parallel to form the DC busbars DCa , DCb , and DCc of the three single-phase full-bridge inverter modules of the low-voltage stage of the solid-state transformer. The biggest advantage of the staggered parallel connection of DC busbars on the low-voltage side is that it structurally solves the mutual influence of the unbalanced high-voltage and low-voltage side systems of the solid-state transformer, and automatically improves the reliability of power supply. As long as one sub-module operates normally, the basic power consumption can be guaranteed. , and its structure is simple and easy to control, which is also the key to the automatic mutual balancing function of the solid-state transformer designed by this patent.
模块化多电平换流器(MMC)的主电路拓扑结构如附图4所示，其中，图4为三相MMC换流器的主电路拓扑，主要由A、B、C三个相单元并联组成，每个相单元包含上下两个桥臂单元，上下桥臂单元均由M个相同的子模块和一个桥臂电抗器串联组成。其中，桥臂电抗器的作用是抑制由各并联相单元的直流电压瞬时值不完全相同而造成的相间环流，同时还能够有效减小直流母线发生故障时故障电流的上升率，抑制冲击电流，从而提高系统的可靠性。图5为子模块的主电路拓扑结构，其中，j＝p，n；k＝1，2...M；z＝a，b，c。主要由两个可控开关器件及反并联二极管和一个直流储能电容组成，其中K1为高速旁路开关，主要有两方面作用：一是当子模块内部出现故障时，如IGBT的损坏，K1闭合旁路故障子模块，使得MMC不必为单个子模块的故障而停机中断；二是为MMC提供冗余子模块，当有故障的子模块被旁路时，冗余子模块投入工作，提高了系统的可靠性。K2为压接式封装晶闸管，其特点是允许通过较大的电流，当MMC直流侧发生短路故障时，首先封锁开关器件，其次导通K2，使三相The main circuit topology of the modular multilevel converter (MMC) is shown in Figure 4, where Figure 4 is the main circuit topology of the three-phase MMC converter, mainly composed of three phase units A, B, and C Composed in parallel, each phase unit contains two upper and lower bridge arm units, and the upper and lower bridge arm units are composed of M identical sub-modules and a bridge arm reactor in series. Among them, the role of the bridge arm reactor is to suppress the phase-to-phase circulation caused by the instantaneous value of the DC voltage of each parallel phase unit is not completely the same, and at the same time, it can effectively reduce the rise rate of the fault current when the DC bus fails, and suppress the inrush current. Thereby improving the reliability of the system. Fig. 5 is the main circuit topology of the sub-module, where j=p, n; k=1, 2...M; z=a, b, c. It is mainly composed of two controllable switching devices, anti-parallel diodes and a DC energy storage capacitor, among which K1 is a high-speed bypass switch, which mainly has two functions: one is when a fault occurs inside the sub-module, such as IGBT damage, K1 Close the bypass fault sub-module, so that the MMC does not have to stop and interrupt for the failure of a single sub-module; the second is to provide redundant sub-modules for the MMC, when the faulty sub-module is bypassed, the redundant sub-module is put into work, which improves the System reliability. K2 is a crimp-packaged thyristor, which is characterized by allowing a large current to pass through. When a short-circuit fault occurs on the MMC DC side, the switching device will be blocked first, and then K2 will be turned on to make the three-phase
的故障电流更多的流过K2，保护反并联的二极管，增强系统的抗故障能力。More fault current flows through K2 to protect the anti-parallel diodes and enhance the system's anti-fault capability.
所述隔离级DC/DC变换器包括隔离级高压侧DC/AC变换模块、隔离级高频变压器和隔离级低压侧AC/DC变换模块；The isolation-level DC/DC converter includes an isolation-level high-voltage side DC/AC conversion module, an isolation-level high-frequency transformer, and an isolation-level low-voltage side AC/DC conversion module;
所述隔离级高频变压器的原边绕组与副边绕组之间变比为2M：3，隔离级低压输出侧AC/DC变换模块的单相全桥AC/DC模块连接低压级直流母线并联模块，完成高频交流方波到低压直流电压的变换。The transformation ratio between the primary winding and the secondary winding of the isolation stage high-frequency transformer is 2M:3, and the single-phase full-bridge AC/DC module of the AC/DC conversion module on the low-voltage output side of the isolation stage is connected to the low-voltage stage DC bus parallel module , to complete the conversion of high-frequency AC square wave to low-voltage DC voltage.
所述低压级DC/AC变换器由低压级直流母线并联模块和三个独立控制的单相全桥逆变器以及对应LC滤波器组成，输出所需要的交流电能，实现固态变压器的电压变换、电能传输和电能质量控制。The low-voltage level DC/AC converter is composed of a low-voltage level DC bus parallel module, three independently controlled single-phase full-bridge inverters and corresponding LC filters, and outputs the required AC power to realize the voltage conversion of the solid-state transformer, Power transmission and power quality control.
本发明还提供一种基于MMC的固态变压器的控制方法，所述控制方法包括以下步骤：The present invention also provides a kind of control method based on MMC solid-state transformer, and described control method comprises the following steps:
步骤1：高压级AC/DC变换器进行电压和电流的双闭环控制、环流抑制控制和子模块电容电压均衡控制；Step 1: The high-voltage AC/DC converter performs double closed-loop control of voltage and current, circulation suppression control and sub-module capacitor voltage equalization control;
所述步骤1中，高压级AC/DC变换器采用定有功功率矢量控制方法在dq坐标系下进行电压和电流的双闭环控制、环流抑制控制和子模块电容电压均衡控制，如图6和图7所示。In the step 1, the high-voltage AC/DC converter adopts the constant active power vector control method to perform double closed-loop control of voltage and current, circulation suppression control and sub-module capacitor voltage equalization control in the dq coordinate system, as shown in Figure 6 and Figure 7 shown.
其中，同步旋转坐标系下的电压和电流双闭环控制策略是为了实现交流输入电流正弦化和单位功率因数控制；子模块电容电压均衡控制是为了实现维持高压侧直流母线电压恒定和MMC电路各子模块直流电容电压均衡；环流抑制控制的作用是按照电压外环输出的有功电流指令值进行输入电流控制。Among them, the voltage and current double closed-loop control strategy under the synchronous rotating coordinate system is to realize the sinusoidalization of the AC input current and unit power factor control; The DC capacitor voltage of the module is balanced; the function of the circulation suppression control is to control the input current according to the active current command value output by the voltage outer loop.
电网电流控制环的作用是按照电压外环输出的有功电流指令值进行输入电流控制，如图6所示，采用电网电压前馈解耦控制使三相AC/DC换流器电流内环(iGd、iGq)实现解耦，并且可消除电网电压扰动。输入电网电流环的输出经等功率坐标变换矩阵后得到abc坐标系下MMC换流器三相交流输出电压给定值emfz。其中，udc为MMC型固态变压器高压侧直流母线电压值；为高压侧直流母线电压参考值；Lg为桥臂电感和电网侧滤波电感之后；uGd和uGq为电网电压的d轴和q轴分量；iGd和iGq为电网电流的d轴和q轴分量；电压外环和电流内环均采用比例积分(PI)控制。The function of the grid current control loop is to control the input current according to the active current command value output by the voltage outer loop, as shown in Fig.Gd , iGq ) realize decoupling, and can eliminate grid voltage disturbance. The output of the input grid current loop is transformed through the equal power coordinate transformation matrix to obtain the given value emfz of the three-phase AC output voltage of the MMC converter in the abc coordinate system. Among them, udc is the DC bus voltage value of the high-voltage side of the MMC solid-state transformer; is the reference value of DC bus voltage on the high-voltage side; Lg is the bridge arm inductance and after the grid side filter inductance; uGd and uGq are the d-axis and q-axis components of the grid voltage; iGd and iGq are the d-axis and q-axis components of the grid current The q-axis component; the voltage outer loop and the current inner loop are both proportional-integral (PI) controlled.
高压级AC/DC变换器采用的环流抑制控制策略框图如图6所示，求解三相桥臂电流ipz和inz的平均值即得三相上、下桥臂环流idiffz。经过负序二倍频旋转坐标变换矩阵T′abc/dq后，得到上下桥臂环流的d、q轴分量icid和iciq，将它们与d、q轴环流的参考值和相比较后，经过PI调节器，并引入2ωLr·icid2和2ωLr·iciq2，以消除MMC环流模型中的dq轴耦合项，即可求得内部不平衡压降d、q轴分量的参考值udiffd2ref和udiffq2ref。为了减小环流的大小，取和均为零。经公式(1)、(2)分别求得上、下桥臂子模块电容电压参考值upz和unz。The block diagram of the circulation suppression control strategy adopted by the high-voltage AC/DC converter is shown in Figure 6. The average value of the three-phase bridge arm currents ipz and inz is calculated to obtain the three-phase upper and lower bridge arm circulation current idiffz . After the negative-sequence double-frequency rotation coordinate transformation matrix T′abc/dq , the d, q-axis components icid and iciq of the upper and lower bridge arm circulation are obtained, and they are compared with the reference values of d, q-axis circulation and After comparison, through the PI regulator and the introduction of 2ωLr icid2 and 2ωLr iciq2 to eliminate the dq-axis coupling item in the MMC circulation model, the internal unbalanced pressure drop d and q-axis components can be obtained Reference values udiffd2ref and udiffq2ref . In order to reduce the size of the circulation, take and are all zero. The reference values upz and unz of the capacitor voltage of the upper and lower bridge arm sub-modules are obtained respectively by formulas (1) and (2).
其中，ud0为高压侧直流母线电压初始值；Among them, ud0 is the initial value of the DC bus voltage on the high voltage side;
负序二倍频旋转坐标变换矩阵T′abc/dq为：The negative sequence double frequency rotation coordinate transformation matrix T′abc/dq is:
高压级AC/DC变换器各子模块直流电容电压的均衡控制策略采用叠加均衡分量法，其控制策略框图如图7所示。该方法是在电压参考信号中叠加均压分量后，除以各子模块各自电容电压值，重新生成每个子模块的调制波。其控制目的是使每个桥臂上所有子模块的电容电压跟踪其参考值。控制器采用单比例调节器，控制每个子模块电容电压跟踪电容电压给定值，其输出uv-jkz为子模块电容电压均衡控制叠加量。根据子模块的工作原理可知，当桥臂电流为充电电流时，为保持各子模块电容电压均衡，应增加电压较低的子模块投入时间，让其充电，因此子模块电容电压均衡控制叠加量取为正。反之亦然。采用载波移相调制策略，每个子模块的调制波与各自的三角载波进行比较发波，产生触发脉冲。The balanced control strategy of the DC capacitor voltage of each sub-module of the high-voltage AC/DC converter adopts the superposition balanced component method, and the control strategy block diagram is shown in Figure 7. In this method, the voltage equalization component is superimposed on the voltage reference signal, and then divided by the respective capacitor voltage values of each sub-module to regenerate the modulation wave of each sub-module. Its control purpose is to make the capacitor voltages of all sub-modules on each bridge arm track its reference value. The controller adopts a single proportional regulator to control the capacitor voltage of each sub-module to track the given value of the capacitor voltage, and its output uv-jkz is the superposition amount of sub-module capacitor voltage equalization control. According to the working principle of the sub-module, when the bridge arm current is the charging current, in order to maintain the balance of the capacitor voltage of each sub-module, the sub-module with a lower voltage should be invested in time to charge it, so the sub-module capacitor voltage balance controls the superposition amount Take as positive. vice versa. Using the carrier phase-shift modulation strategy, the modulation wave of each sub-module is compared with its own triangular carrier wave to generate a trigger pulse.
所述步骤2中，隔离级DC/DC变换器采用开环控制策略进行高压级AC/DC变换器与低压级DC/AC变换器之间的电气隔离以及电压等级变换控制，如图8所示。步骤2包括以下步骤：In the step 2, the isolation-level DC/DC converter adopts an open-loop control strategy to perform electrical isolation and voltage level conversion control between the high-voltage level AC/DC converter and the low-voltage level DC/AC converter, as shown in Figure 8 . Step 2 consists of the following steps:
步骤2-1：高压级AC/DC变换器输出的高压直流电压经隔离级高压侧DC/AC变换模块调制成高频交流方波；Step 2-1: The high-voltage DC voltage output by the high-voltage stage AC/DC converter is modulated into a high-frequency AC square wave by the DC/AC conversion module on the high-voltage side of the isolation stage;
步骤2-2：高频交流方波经隔离级高频变压器同步耦合至隔离级低压侧AC/DC变换模块；Step 2-2: The high-frequency AC square wave is synchronously coupled to the AC/DC conversion module on the low-voltage side of the isolation stage through the isolation-level high-frequency transformer;
步骤2-3：耦合至隔离级低压侧AC/DC变换模块的高频交流方波经隔离级低压侧AC/DC变换模块同步整流为低压直流电压，输出给低压级DC/AC变换器。Step 2-3: The high-frequency AC square wave coupled to the AC/DC conversion module on the low-voltage side of the isolation stage is synchronously rectified into a low-voltage DC voltage by the AC/DC conversion module on the low-voltage side of the isolation stage, and output to the low-voltage DC/AC converter.
所述步骤3中，低压级DC/AC变换器采用双环控制策略进行相电压有效值恒定控制，并实现波形正弦化。In the step 3, the low-voltage stage DC/AC converter adopts a double-loop control strategy to control the effective value of the phase voltage constant, and realizes sinusoidal waveform.
步骤3：低压级DC/AC变换器进行相电压有效值恒定控制并实现波形正弦化，如图9所示，外环为相电压有效值控制环，保持输出电压有效值不变，内环为相电压瞬时值控制环，使得相电压跟踪给定正弦波电压，维持输出波形的良好正弦性。Step 3: The low-voltage level DC/AC converter performs constant control of the effective value of the phase voltage and realizes sinusoidal waveform, as shown in Figure 9, the outer loop is the control loop of the effective value of the phase voltage to keep the effective value of the output voltage unchanged, and the inner loop is The phase voltage instantaneous value control loop makes the phase voltage track the given sine wave voltage and maintains the good sine of the output waveform.
所述步骤3包括以下步骤：Described step 3 comprises the following steps:
步骤3-1：在外环控制策略中，先通过相电压瞬时值得到实际相电压有效值，然后将相电压有效值与相电压指令值进行比较，得到的偏差经过PI控制器后与标准正弦信号相乘，作为内环控制策略中相电压瞬时值的指令值；Step 3-1: In the outer loop control strategy, the actual effective value of the phase voltage is first obtained through the instantaneous value of the phase voltage, and then the effective value of the phase voltage is compared with the command value of the phase voltage, and the obtained deviation is compared with the standard sinusoidal value after passing through the PI controller The signals are multiplied and used as the command value of the instantaneous value of the phase voltage in the inner loop control strategy;
步骤3-2：在内环控制策略中，先将外环控制策略中输出的相电压瞬时值的指令值与反馈的实际相电压瞬时值相比较，然后将其误差量经比例控制器后作为调制波指令信号，最后并将该调制波指令信号与三角载波信号比较，形成脉冲触发信号以触发功率开关器件正确动作。Step 3-2: In the inner loop control strategy, first compare the command value of the instantaneous value of the phase voltage output in the outer loop control strategy with the actual feedback instantaneous value of the phase voltage, and then pass the error amount through the proportional controller as The modulated wave command signal is finally compared with the triangular carrier signal to form a pulse trigger signal to trigger the correct action of the power switching device.
理论上，输出级通过相电压有效值外环控制，可以实现输出电压有效值稳态无差，从而保证当负载变化或系统受干扰时，输出电压有效值不变。而内环对输出电压瞬时值进行控制，使得相电压跟踪给定正弦波电压，维持输出波形的良好正弦性。Theoretically, the output stage is controlled by the outer loop of the effective value of the phase voltage, so that the effective value of the output voltage can be stabilized without any difference, so as to ensure that the effective value of the output voltage remains unchanged when the load changes or the system is disturbed. The inner loop controls the instantaneous value of the output voltage so that the phase voltage tracks the given sine wave voltage and maintains the good sine of the output waveform.
最后应当说明的是：以上实施例仅用以说明本发明的技术方案而非对其限制，所属领域的普通技术人员参照上述实施例依然可以对本发明的具体实施方式进行修改或者等同替换，这些未脱离本发明精神和范围的任何修改或者等同替换，均在申请待批的本发明的权利要求保护范围之内。Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Those of ordinary skill in the art can still modify or equivalently replace the specific implementation methods of the present invention with reference to the above embodiments. Any modifications or equivalent replacements departing from the spirit and scope of the present invention are within the protection scope of the claims of the pending application of the present invention.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106026685A (en)* | 2016-05-23 | 2016-10-12 | 清华大学 | Topological structure of three-phase power electronic transformer employing low-fluctuation DC bus capacitors |
| CN106452099A (en)* | 2016-10-10 | 2017-02-22 | 中国矿业大学(北京) | Novel connection method of three-phase cascade convertor and working mode during power supply or load fault |
| CN106655239A (en)* | 2017-01-06 | 2017-05-10 | 许继电气股份有限公司 | Combined current converter and internal DC voltage balance control method thereof |
| CN106997012A (en)* | 2017-04-28 | 2017-08-01 | 荣信汇科电气技术有限责任公司 | The converter valve Tests at Steady State device and method of bias voltage is undertaken using electric capacity |
| CN107045092A (en)* | 2017-05-16 | 2017-08-15 | 广东电网有限责任公司惠州供电局 | One kind station change low-voltage alternating-current looped network intelligent detection device and method |
| CN107370392A (en)* | 2017-07-05 | 2017-11-21 | 东南大学 | Towards the electric power electric transformer of mesohigh intelligent distribution network |
| CN108418221A (en)* | 2018-03-07 | 2018-08-17 | 许继电气股份有限公司 | An AC voltage control method and device applied to a flexible direct current transmission system |
| CN108768191A (en)* | 2018-07-10 | 2018-11-06 | 南京工业大学 | Control method for voltage sharing of rectifying stages of single-phase multi-module cascade solid-state transformer |
| CN109217695A (en)* | 2017-06-29 | 2019-01-15 | 中车株洲电力机车研究所有限公司 | The pressure equalizing control method of cascade solid-state transformer |
| CN109950923A (en)* | 2019-03-26 | 2019-06-28 | 国网北京市电力公司 | AC-AC conversion device, grid connection method and device |
| CN110112942A (en)* | 2019-04-22 | 2019-08-09 | 上海交通大学 | The control method of voltage fluctuation of capacitor in suppression module solid-state transformer |
| CN110336462A (en)* | 2019-06-19 | 2019-10-15 | 平高集团有限公司 | A DC power electronic transformer and its control method and device |
| CN110829865A (en)* | 2019-11-07 | 2020-02-21 | 国网江苏省电力有限公司电力科学研究院 | Self-adaptive switching method, device and system suitable for power electronic transformer |
| CN111262425A (en)* | 2020-03-31 | 2020-06-09 | 安可达技术(苏州)有限公司 | Control system and method of staggered totem-pole power factor correction circuit |
| CN111384718A (en)* | 2020-02-27 | 2020-07-07 | 华为技术有限公司 | Power supply device, power supply system and data center |
| CN111600494A (en)* | 2019-08-09 | 2020-08-28 | 青岛鼎信通讯股份有限公司 | Control method for improving running performance of power electronic transformer after redundancy |
| CN111817599A (en)* | 2020-07-16 | 2020-10-23 | 哈尔滨工业大学 | Multiport power router and control method thereof |
| CN112039314A (en)* | 2020-09-07 | 2020-12-04 | 华中科技大学 | Load current feedforward control strategy and system for MMC type power electronic transformers |
| CN112953254A (en)* | 2021-03-29 | 2021-06-11 | 山东电工电气集团有限公司 | Three-phase power electronic transformer topology and control method thereof |
| CN113241962A (en)* | 2021-06-07 | 2021-08-10 | 昆明理工大学 | Power electronic transformer based on three-phase four-leg MMC and control method thereof |
| WO2022068531A1 (en)* | 2020-09-30 | 2022-04-07 | 阳光电源股份有限公司 | Cascaded multi-port converter and three-phase medium-voltage input system |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101917126A (en)* | 2010-07-30 | 2010-12-15 | 浙江大学 | A control method for voltage equalization and power equalization of multi-module cascaded solid-state transformers |
| CN103208929A (en)* | 2013-04-22 | 2013-07-17 | 广东电网公司电力科学研究院 | Electronic power transformer based on multi-media card (MMC) |
| CN103516230A (en)* | 2013-10-14 | 2014-01-15 | 国家电网公司 | Bi-directional power flow controlled multi-level mutual balance solid state transformer and realization method thereof |
| CN104638940A (en)* | 2015-03-02 | 2015-05-20 | 东南大学 | Modular multi-level power electronic transformer based on cascading |
| US20150155716A1 (en)* | 2013-12-03 | 2015-06-04 | Board Of Trustees Of The University Of Arkansas | Power Electronic Interface for Connecting Two AC Systems |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101917126A (en)* | 2010-07-30 | 2010-12-15 | 浙江大学 | A control method for voltage equalization and power equalization of multi-module cascaded solid-state transformers |
| CN103208929A (en)* | 2013-04-22 | 2013-07-17 | 广东电网公司电力科学研究院 | Electronic power transformer based on multi-media card (MMC) |
| CN103516230A (en)* | 2013-10-14 | 2014-01-15 | 国家电网公司 | Bi-directional power flow controlled multi-level mutual balance solid state transformer and realization method thereof |
| US20150155716A1 (en)* | 2013-12-03 | 2015-06-04 | Board Of Trustees Of The University Of Arkansas | Power Electronic Interface for Connecting Two AC Systems |
| CN104638940A (en)* | 2015-03-02 | 2015-05-20 | 东南大学 | Modular multi-level power electronic transformer based on cascading |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106026685A (en)* | 2016-05-23 | 2016-10-12 | 清华大学 | Topological structure of three-phase power electronic transformer employing low-fluctuation DC bus capacitors |
| CN106452099A (en)* | 2016-10-10 | 2017-02-22 | 中国矿业大学(北京) | Novel connection method of three-phase cascade convertor and working mode during power supply or load fault |
| CN106655239A (en)* | 2017-01-06 | 2017-05-10 | 许继电气股份有限公司 | Combined current converter and internal DC voltage balance control method thereof |
| CN106997012A (en)* | 2017-04-28 | 2017-08-01 | 荣信汇科电气技术有限责任公司 | The converter valve Tests at Steady State device and method of bias voltage is undertaken using electric capacity |
| CN106997012B (en)* | 2017-04-28 | 2023-07-14 | 荣信汇科电气股份有限公司 | Device and method for steady-state operation test of converter valve using capacitor to bear bias voltage |
| CN107045092A (en)* | 2017-05-16 | 2017-08-15 | 广东电网有限责任公司惠州供电局 | One kind station change low-voltage alternating-current looped network intelligent detection device and method |
| CN107045092B (en)* | 2017-05-16 | 2023-04-07 | 广东电网有限责任公司惠州供电局 | Intelligent detection device and method for low-voltage alternating-current ring network for station |
| CN109217695A (en)* | 2017-06-29 | 2019-01-15 | 中车株洲电力机车研究所有限公司 | The pressure equalizing control method of cascade solid-state transformer |
| CN107370392B (en)* | 2017-07-05 | 2019-03-29 | 东南大学 | Electric power electric transformer towards mesohigh intelligent distribution network |
| CN107370392A (en)* | 2017-07-05 | 2017-11-21 | 东南大学 | Towards the electric power electric transformer of mesohigh intelligent distribution network |
| CN108418221B (en)* | 2018-03-07 | 2020-01-10 | 许继电气股份有限公司 | Alternating current voltage control method and device applied to flexible direct current transmission system |
| CN108418221A (en)* | 2018-03-07 | 2018-08-17 | 许继电气股份有限公司 | An AC voltage control method and device applied to a flexible direct current transmission system |
| CN108768191A (en)* | 2018-07-10 | 2018-11-06 | 南京工业大学 | Control method for voltage sharing of rectifying stages of single-phase multi-module cascade solid-state transformer |
| CN109950923A (en)* | 2019-03-26 | 2019-06-28 | 国网北京市电力公司 | AC-AC conversion device, grid connection method and device |
| CN110112942B (en)* | 2019-04-22 | 2020-10-30 | 上海交通大学 | Control Method for Suppressing Capacitor Voltage Fluctuation in Modular Solid State Transformer |
| CN110112942A (en)* | 2019-04-22 | 2019-08-09 | 上海交通大学 | The control method of voltage fluctuation of capacitor in suppression module solid-state transformer |
| CN110336462A (en)* | 2019-06-19 | 2019-10-15 | 平高集团有限公司 | A DC power electronic transformer and its control method and device |
| CN111600494A (en)* | 2019-08-09 | 2020-08-28 | 青岛鼎信通讯股份有限公司 | Control method for improving running performance of power electronic transformer after redundancy |
| CN110829865A (en)* | 2019-11-07 | 2020-02-21 | 国网江苏省电力有限公司电力科学研究院 | Self-adaptive switching method, device and system suitable for power electronic transformer |
| CN110829865B (en)* | 2019-11-07 | 2021-04-13 | 国网江苏省电力有限公司电力科学研究院 | Self-adaptive switching method, device and system suitable for power electronic transformer |
| CN111384718A (en)* | 2020-02-27 | 2020-07-07 | 华为技术有限公司 | Power supply device, power supply system and data center |
| US12169428B2 (en) | 2020-02-27 | 2024-12-17 | Huawei Digital Power Technologies Co., Ltd. | Power supply apparatus, power supply system, and data center |
| CN111262425B (en)* | 2020-03-31 | 2021-03-09 | 安可达技术(苏州)有限公司 | Control system and method of staggered totem-pole power factor correction circuit |
| CN111262425A (en)* | 2020-03-31 | 2020-06-09 | 安可达技术(苏州)有限公司 | Control system and method of staggered totem-pole power factor correction circuit |
| CN111817599A (en)* | 2020-07-16 | 2020-10-23 | 哈尔滨工业大学 | Multiport power router and control method thereof |
| CN112039314A (en)* | 2020-09-07 | 2020-12-04 | 华中科技大学 | Load current feedforward control strategy and system for MMC type power electronic transformers |
| WO2022068531A1 (en)* | 2020-09-30 | 2022-04-07 | 阳光电源股份有限公司 | Cascaded multi-port converter and three-phase medium-voltage input system |
| CN112953254A (en)* | 2021-03-29 | 2021-06-11 | 山东电工电气集团有限公司 | Three-phase power electronic transformer topology and control method thereof |
| CN113241962A (en)* | 2021-06-07 | 2021-08-10 | 昆明理工大学 | Power electronic transformer based on three-phase four-leg MMC and control method thereof |
| CN113241962B (en)* | 2021-06-07 | 2023-11-28 | 昆明理工大学 | Power electronic transformer based on three-phase four-bridge arm MMC and control method thereof |
| Publication number | Publication date |
|---|---|
| CN105490552B (en) | 2019-08-16 |
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