基于单周控制技术的逆变电源研究

摘要随着现代新能源的开发和利用，新的逆变技术不断的出现和发展。

功率变换技术是现代逆变系统中最重要的技术之一，而脉冲宽度调制（PWM）技术则是主要的功率变换技术。

各种在概念上和性能上不同的PWM技术，设计电压源逆变器时，选择功率变换技术的主要依据是负载类型、功率级、功率变换器的功率开关器件等等因素。

对于具体的应用而言，选择一种PWM控制技术的最终决定因素是性能要求及成本标准。

单周控制技术是1991年由Keyue M.Smedley和Slobodan Cuk首次提出的大信号非线性控制技术，它主要是恒频开关工作的PWM 技术。

单周控制技术恰好克服了常规PWM技术固有的缺点：单周控制的开关频率是固定的，既改善了输出波形的质量，又降低了输出波形的谐波含量；单周控制的开关变量平均值在一个开关周期内严格跟踪参考给定，且开关变量平均值与控制参考之间既没有稳态误差，也没有暂态误差。

针对工业应用的实际需要，将单周控制技术应用于逆变电源中，给负载提供所需要的交流电压源。

文章根据单周控制原理，解决了两个关键性的问题。

首先，用双通道积分器交互工作解决了积分器的复位问题；再用增加直流偏移量解决实际电路中遇到的电压测量问题。

对逆变电源电路而言，提高直流电压利用率可以提高逆变器的输出能力，减少逆变器开关的动作次数，就能减少开关损耗。

采用双通道积分器单周控制的电压型逆变电源，其硬件电路结构简单，输出电压幅值和频率可调，具有快速的动态响应，较强的抑制电源扰动能力和抗负载扰动能力，直流电压利用率可达到92.8%，电压总谐波畸变率（THD）最小为0.2559%，降低了谐波损耗。

本文就是在单周控制技术的基础上，对单相逆变电源系统进行了详细的仿真分析，且与基于SPWM技术的单相逆变电源性能进行了仿真结果比较，最后对基于这两种技术的三相逆变电源也简单的进行仿真比较分析。

从仿真结果知道，在理想的开关条件下，单周控制技术逆变电源与SPWM逆变电源的输出电压波形性能相当；但在考虑实际器件的死区影响时，单周控制技术的优点就明显体现出来了。

为了验证理论的可行性，本文还对基于单周控制技术的单相逆变电源进行了实验。

实验结果和仿真结果是一致的，从而说明了单周控制技术用于逆变电源的优越性。

通过理论研究及实验验证，单周控制技术适用于电压源型逆变电源系统，且该逆变电源是一种较标准的交流电源。

关键词：可调交流电源，单周控制，逆变器ABSTRACTThe power converter technique is one of the most important inverter techniques. And the pulse-width modulation techniques are the major part of the power converter techniques,which have been the subject of intensive research during the last few decades.A large variety of methods,different in concept and performance,have been newly developed and described.Their implementation in the design of the voltage source inverters depends on the load types,the power level,and the semiconductor devices used in the power converter.It is lastly performance and cost criteria to determine the choice of a PWM method in a specific application.A new nonlinear control technique is proposed to control the duty-ratio of the switch such that in each cycle the average value of the switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient.It improves the output waveform quality,and also abates the undesired harmonic contents.However,the one-cycle control(OCC)technique has shown excellent improvement compared with conventional sinusoidal pulse width modulation (SPWM).By using of one-cycle control theory,a novel voltage source inverter is proposed. The conventional one-cycle control technique needs that the integrator is reset instantaneously.But it is very difficult to realize by hardware due to the finite time constant of the reset circuitry.Therefore,based on the one-cycle control technique,the paper gives a new control scheme to resolve the problem with dual channel integrator, and the performance of the integrators is close to ideal.The paper also uses the dc offset to implement the voltage measurement.Further more,the amplitude and frequency of the output voltage are effectively adjustable.Based on the one-cycle control technique,this paper gives the simulation details of the one-phase source, whose simulation results compare with the voltage source inverter based on the SPWM. And the paper simply shows the simulation results of three-phase voltage inverter source based on the one-cycle technique and the SPWM.For the voltage source inverter,the most important point is the performance of the output voltage.And the key factor is the harmonic distortion and the modulation index of the inverter. Comparative studies are conducted to characterize the output distortions of the voltage source inverters which controlled by SPWM and one-cycle control technique.Simulation results with a10kHz switching frequency have shown that OCC has better performances.By comparison,in the ideal switch conditions,both two methods are about the same performances of output voltages.When we consider the influence of switching dead time,SPWM controlled inverter is worse than OCC controlled inverter. The one-cycle control technique not only provides fast dynamic response,but also can admirably suppress the perturbation yielded by dc source and abate the undesired harmonic contents.Simulation studies were performed to prove the proposed scheme. The results show that the one-cycle control based voltage source inverter makes good use of dc-link voltage that is92.8%and THD is only0.2559%.In conclusion,the simulation and experiment results demonstrate that the one-cycle control technique is suitable and feasible for power converter or voltage source inverter.Keywords:adjustable ac source,one-cycle control,voltage source inverter1绪论1.1逆变电源技术的现状与发展随着各行各业控制技术的发展和对操作性能要求的提高，许多行业的用电设备都不是直接使用通用交流电网提供的交流电作为电能源，而是通过各种形式对其进行变换，从而得到各自所需的电能形式。