﻿ 一种基于PQ控制的DG逆变器模型 A DG Inverter Model Based on PQ Control

Journal of Electrical Engineering
Vol.05 No.02(2017), Article ID:20903,6 pages
10.12677/JEE.2017.52020

A DG Inverter Model Based on PQ Control

Jiangang Du1, Hong Zhang2

1State Grid Chengdu Electric Power Supply Company, Chengdu Sichuan

2School of Electrical and Information Engineering, Southwest Petroleum University, Chengdu Sichuan

Received: May 21st, 2017; accepted: Jun. 6th, 2017; published: Jun. 9th, 2017

ABSTRACT

Grid-connected inverter as a link between the distributed power supply and power grid, plays a key role to the distributed power supply and the network performance. In this paper, a DG inverter model based on PQ control is designed. The inverter is selected by using the three-phase bridge PWM inverter, and the KCL and KVL are used to model the mathematical model. The mathematical model is analyzed by the mathematical model so as to carry out the design of the inverter controller. PQ control module (Controller) provides the dq conversion module mainly by the frequency tracking effect of the SPLL and coordinate transformation (SPLL/dq_transform); it can get the reference current dq component (iLdref, iLqref), power and power factor control (P/Q control) module, and the final can be 6-way PWM control signal current control (I Control) module. The simulation results show that the DG inverter model based on PQ control is excellent in performance.

Keywords:PQ Control, DG Inverter, SPWM Modulation

1国家电网成都供电公司，四川 成都

2西南石油大学电气信息学院，四川 成都

1. 引言

2. 逆变模块主电路搭建

3. PQ控制模块(Controller)搭建

PQ控制模块(Controller)主要由具有频率跟踪作用的SPLL与提供坐标变换的dq变换模块(SPLL/dq_transform)、能够得到参考电流dq分量(iLdref, iLqref)的功率及功率因数控制(P/Q Control)模块、以及最终能够得到6路PWM控制信号的电流控制(I Control)模块，Controller的仿真模型如图2所示。

Figure 1. Three phase PWM inverter main circuit

Figure 2. Controller model

SPLL/dq_transform锁相环节能够有效的跟踪输入电压uabc(不易受电压扰动的影响)，兼具良好的滤波效果，达到实时跟踪电网频率，同时为dq环节提供参考角频率ω(使uq = 0)的目的，dq坐标变换由abc_to_dq0 Transformation模块提供 [6] 。其仿真模型如图3所示，图4为SPLL模块频率跟踪仿真图。

I Control模块内部只要包括PI环节(Discrete PI Controller模块)、电压前馈补偿、dq变换环节，得到参考电压udref、uqref，通过坐标变换(abc_to_dq0 Transformtion模块)，得到所需的Uref，经PWM发生器，生成6路PWM控制信号。其中Discrete PI Controller模块中KpP = KpQ = 0.5，KiP = KiQ = 20。其仿真模型如图6所示。

Figure 3. SPLL/dq_transform model

Figure 4. SPLL module frequency tracking simulation

Figure 5. P/Q Control model

Figure 6. I Control model

Figure 7. Open loop frequency response

4. 结论

1) 针对电流内环控制系统的开环频域响应仿真曲线可知，在该控制系统中加入PI环节后，控制系统的相角裕度相应增加，因而使得控制系统稳定性得以提高。

Figure 8. Closed loop frequency response

2) 针对电流内环控制系统的闭环频域响应仿真曲线可以看出，在该控制系统中加入PI环节后，控制系统的截止频率f0相应下降(从图中可以看出其数量级由104减小至103)，从而使得系统在高频时性能得以提升。

A DG Inverter Model Based on PQ Control[J]. 电气工程, 2017, 05(02): 167-172. http://dx.doi.org/10.12677/JEE.2017.52020

1. 1. 华志强. 含分布式发电系统的配电网无功优化研究[D]: [硕士学位论文]. 西安: 西安理工大学, 2011.

2. 2. 陈明军, 连新凯, 黄飞腾, 等. 含DG的多电源配电系统的故障分析[J]. 机电工程, 2012, 29(10): 1205-1208.

3. 3. 丁明, 王敏. 分布式发电技术[C]//中国高等学校电力系统及其自动化专业学术年会. 中国高等学校电力系统及其自动化专业第20届学术年会论文集(上册). 2004.

4. 4. 潘国清, 曾德辉, 王钢, 等. 含PQ控制逆变型分布式电源的配电网故障分析方法[J]. 中国电机工程学报, 2014, 34(4): 555-561.

5. 5. 潘国清. 含PQ控制逆变型分布式电源的配电网故障分析[D]: [硕士学位论文]. 广州: 华南理工大学, 2014.

6. 6. 吉正华, 韦芬卿, 杨海英. 基于dq变换的三相软件锁相环设计[J]. 电力自动化设备, 2011, 31(4): 104-107.