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介绍了一种基于数字信号处理器的半导体激光器PWM温度控制系统,给出了一种采用比较放大的热电制冷器驱动电路,能避免MOSFET桥的直通短路。在数字控制系统中,采用32位TMS320F2812芯片作为控制核心,通过其GPIOA0口从数字式温度传感器DS18B20中读取半导体激光器的工作温度,使用事件管理器输出的PWM信号来控制热电制冷器工作。针对半导体激光器对温度稳定性的要求,利用DSP强大的运算能力,采用参数自整定的模糊PID算法实现系统的温度控制。在实验室环境下,采用载波频率为50kHz的PWM控制,系统在2min内成功将半导体激光器的工作温度稳定在25.0±0.1℃,且超调量不大于0.5℃。实验结果证明:采用DSP技术,能更好地实现算法的控制效果,提高系统控制的精确度和稳定度;采用比较放大的TEC驱动电路,能有效解决传统驱动电路的“死区”问题。
A semiconductor laser PWM temperature control system based on digital signal processor is introduced. A thermoelectric cooler drive circuit using a relatively enlarged amplifier is given, which can avoid the direct-flow short circuit of the MOSFET bridge. In the digital control system, the 32-bit TMS320F2812 chip is used as the control core, the operating temperature of the semiconductor laser is read from the digital temperature sensor DS18B20 via its GPIOA0 port, and the PWM signal output by the event manager is used to control the operation of the thermoelectric cooler. Aiming at the requirement of temperature stability of semiconductor laser, DSP is used to realize the temperature control of system by using the powerful arithmetic ability of DSP and the fuzzy PID algorithm of parameter self-tuning. In the lab environment, PWM control with carrier frequency of 50kHz was adopted. The system successfully stabilized the working temperature of semiconductor laser at 25.0 ± 0.1 ℃ in 2min and the overshoot was no more than 0.5 ℃. Experimental results show that using DSP technology can better realize the control effect of the algorithm and improve the accuracy and stability of the system control. By using the amplified TEC drive circuit, the problem of “dead zone” of the conventional drive circuit can be effectively solved .