数字式单相逆变电源优化控制技术的研究

发布时间：2019-06-25 18:46

【摘要】：在逆变器发展初期,大多采用模拟电路和开环控制,这种方式的电路结构简单、成本低,但是输出电压的波形发生了明显畸变,总谐波系数(THD)大、输出电压波形受负载影响大且不可控。因此,在对输出电压质量要求不高的场合,可以使用开环控制系统,而对电能质量要求较高的场合,必须使用闭环控制系统。随着数字信号处理器(DSP)的发展,逆变电源的数字化电路设计成为可能。数字化控制系统的可靠性高、硬件电路结构简单、能够方便实现实时控制和多种控制算法。本文对单相全桥逆变电路的三种正弦脉冲宽度调制(SPWM)方式进行了理论分析与仿真对比[1],得出单极性倍频SPWM技术能够更好地抑制负载端输出电压的谐波。为了实现逆变电源的数字化控制,分析了规则采样法和自然采样法。文章对单相全桥逆变电路的数字控制系统进行了仿真研究,设计PI控制外环和重复控制内环组成的双闭环控制系统,该数字控制系统将负载端的输出电压作为被控量和参考标准。其中,PI外环是对负载端输出电压的均值进行控制,重复控制内环是对其瞬时值进行校正,PI外环可以根据负载的变化来相应地调节重复控制内环的给定值,从而使单相全桥逆变电路的输出电压波形有了很大的改进。以TMS320F2812DSP为核心的数字控制系统,熟悉整个硬件电路和软件程序的设计,包括逆变电源主电路、电源结构、驱动电路、保护电路和滤波电路等。软件设计采用模块化程序结构,包括主程序、A/D、产生SPWM波形等子程序模块。最后,在TMS320F2812DSP为控制芯片的实验平台上,完成该数字控制系统的调试。实验结果表明该数字控制系统能够产生比较理想的输出电压波形,证明了其控制系统的可行性和有效性。
[Abstract]:In the early stage of inverter development, analog circuits and open-loop control are mostly used. The circuit structure of this method is simple and the cost is low, but the waveform of output voltage has been obviously distorted, the total harmonic coefficient (THD) is large, and the output voltage waveform is greatly affected by load and uncontrollable. Therefore, the open-loop control system can be used in the case of low output voltage quality, but the closed-loop control system must be used in the case of high power quality requirements. With the development of digital signal processor (DSP), the digital circuit design of inverter power supply is possible. The digital control system has high reliability and simple hardware circuit structure, and can easily realize real-time control and various control algorithms. In this paper, three sinusoidal pulse width modulation (SPWM) methods for single-phase full-bridge inverter circuits are theoretically analyzed and compared with simulation [1]. It is concluded that unipolar frequency doubling SPWM technology can better suppress the harmonics of the output voltage at the load end. In order to realize the digital control of inverter power supply, the regular sampling method and natural sampling method are analyzed. In this paper, the digital control system of single-phase full-bridge inverter circuit is simulated and studied, and a double closed-loop control system composed of PI control outer loop and repeated control inner loop is designed. The digital control system takes the output voltage at the load end as the controlled quantity and reference standard. Among them, the PI outer loop controls the mean output voltage of the load terminal, and the repetitive control inner loop corrects its instantaneous value. The PI outer loop can adjust the given value of the repetitive control inner loop according to the change of the load, so that the output voltage waveform of the single-phase full-bridge inverter circuit has been greatly improved. The digital control system based on TMS320F2812DSP is familiar with the design of the whole hardware circuit and software program, including the main circuit of inverter power supply, power structure, driving circuit, protection circuit and filter circuit. The software design adopts modular program structure, including main program, A / D, generating SPWM waveform and other subroutine modules. Finally, the digital control system is debugged on the experimental platform of TMS320F2812DSP as the control chip. The experimental results show that the digital control system can produce ideal output voltage waveform, which proves the feasibility and effectiveness of the control system.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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