Abstract Pulse Width Modulation (PWM) is widely used for controlling electronic signal transmission, particularly in direct current (DC) motor control. This paper focuses on the application of PWM in controlling DC motors. The operating principle of PWM reveals that the frequency plays a crucial role in determining the precision of DC motor control. Generally, higher PWM frequencies result in smoother and more accurate motor operation. However, simulation experiments in this paper indicate that excessively high PWM frequencies can disrupt the linear relationship between control precision and frequency, leading to a significant decrease in motor speed. Based on the experiment conducted under Proteus simulation software and using an 8051 series microcontroller to generate PWM signals at various frequencies, this paper explores the impact of PWM frequency on DC motor speed. The analysis of simulated components demonstrates that at high PWM frequencies, the integrated circuit L293D experiences increased switching losses, and higher power dissipated. Additionally, the self-inductance phenomenon in DC motors becomes more pronounced with high-frequency signal transitions. Both the switching losses and self-inductance ultimately contribute to the reduction in motor speed, compromising control precision.
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