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实践证明,用脉冲调宽放大器驱动直流电机较比例放大器具有很多的优点。本文的目的就是为了更充分地了解和利用这些优点。本文首先论述了脉冲调宽放大器的基本原理和特性。通过放大器的简化模型,列出单向和双向的放大器——电机系统的微分方程。这些数学模型为放大器带电感性负载(如直流电机)的稳态电流波形提供了分析工具。研究了串联电感对稳态电流的影响。最后,讨论了脉冲调宽放大器中引入的电流反馈对闭环系统动态特性的影响及其短路保护作用。
Practice has proved that using a pulse width modulated amplifier to drive a DC motor has many advantages over a proportional amplifier. The purpose of this article is to get a fuller understanding and use of these benefits. This paper first discusses the basic principle and characteristics of pulse width modulation amplifier. A simplified model of the amplifier lists the differential equations of the uni-directional and bi-directional amplifier-motor system. These mathematical models provide the analytical tools for the amplifier’s steady-state current waveforms with inductive loads such as DC motors. The effect of series inductance on steady-state current is studied. Finally, the influence of the current feedback introduced in the pulse width-modulated amplifier on the dynamic characteristics of the closed-loop system and its short-circuit protection are discussed.