【作者】 辛爱芹；

【导师】 王萍；

【作者基本信息】 天津大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 电力电子技术的发展一方面给电能变换和应用带来了方便,另一方面带来了电能质量问题。例如:谐波污染、无功问题、三相不平衡、电压波动、电压骤降等。有源滤波技术在改善电能质量中得到了广泛的应用,其中统一电能质量调节器(UPQC)不仅能够实现畸变波形的补偿,而且能够实现动态电压恢复。本文将统一电能质量调节器分为电压补偿部分和电流补偿部分,探索了一种新的拓扑结构及其控制方法。本文的主要内容有:电压补偿主电路采用电压源型逆变器通过单相升压变压器串联接入电网,电流补偿主电路设计了一种三相切换电容主电路并联接入电网,这样的拓扑结构电压补偿部分需要的直流电压较小,相应的电容也会减小,且切换电容电路中的电感、电容远比电压源型逆变器主电路的小,因此大大减小了UPQC的体积与成本。研究了一种UPQC补偿参考信号与电网电压的软件同步的方法,以简化硬件电路设计。软件算法是基于傅立叶分析和对称分量法得到相电压单位基波分量或基波正序分量,以此作为电压补偿和电流补偿共同的同步信号,以实现两者的同步协调。电压补偿部分采用人为设定负载期望有效值的方法进一步获得标准电压信号,从而获得电压补偿参考信号,而电流补偿部分采用瞬时无功功率理论的i_p-i_q运算方式获得电流标准信号,从而获得电流补偿参考信号。电压补偿控制策略是一种简单快速SVPWM方法;电流补偿控制策略探索了一种神经网络滞环控制。在Matlab的Simulink仿真环境下,建立了仿真模型,仿真结果显示此种策略的统一电能质量调节器控制效果良好。更多还原

【Abstract】 The popularity of power electronics brings convenience to energy conversion and utilization on one hand and also brings negative impact to power quality on the other hand, such as harmonic contamination, excessive reactive power consumption, unbalance, voltage fluctuation and voltage sag. Active power filter technique plays a major role in solving the problem. Unified power quality controller (UPQC) is one of the examples. It not only compensates the distortion of waveform, but also serves as dynamic voltage restorer. This paper discusses a new topology of UPQC, in which the conventional UPQC was divided into a voltage compensation section and a current compensation section respectively.The voltage compensation section comprises a voltage source inverter connected to grid in series by a single-phase step-up transformer. The current compensation section employs a three-phase switched capacitor connected in parallel to the grid. Such topology requires lower DC voltage, so the capacitance of the capacitor and then the total costs can be effectively reduced.This paper also developed a software-based synchronize method for determining the compensation signal according to the grid voltage. This software-based method, attempt to derive the unity fundamental component or positive sequence fundamental component of the phase voltage by using Fourier analysis and symmetric component method, helps to simplify the hardware design. Then the synchronizing signal can be calculated to realize the synchronization of voltage and current compensation. In the voltage compensation section, the reference signal is calculated according to the standard voltage signal which is determined by a preset desired RMS load. In the current compensation section, the standard current is calculated using the i_p-i_q calculation method in the instantaneous reactive power theory. Then the current compensation reference signal can be derived.The voltage compensation strategy is a renovated SVPWM method, which is more simple and faster. The current compensation strategy is a novel control method based on neural network hysteresis loop. All these control strategies were simulated using the Matlab, and fairly satisfactory results were showed in the simulation.更多还原